Human Physiology:Human Physiology:

The Systems of the BodyThe Systems of the Body

By Mindy ChenBy Mindy Chen

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The Human Body: Systems MenuThe Human Body: Systems Menu

Nervous SystemNervous System

Circulatory SystemCirculatory System

Skeletal SystemSkeletal System

Muscular SystemMuscular System

Reproductive SystemReproductive System

Digestive SystemDigestive System

Excretory SystemExcretory System

Respiratory SystemRespiratory System

Integumentary SystemIntegumentary System

Immune SystemImmune System

Endocrine SystemEndocrine System

EXITEXIT

The Nervous System: StandardsThe Nervous System: Standards

Standards:Standards: b. Students know how the nervous system mediates b. Students know how the nervous system mediates

communication between different parts of the body and communication between different parts of the body and the body’s interactions with the environmentthe body’s interactions with the environment

c. Students know how feedback loops in the nervous c. Students know how feedback loops in the nervous and endocrine systems regulate conditions in the bodyand endocrine systems regulate conditions in the body

d. Students know the functions of the nervous system d. Students know the functions of the nervous system and the role of neurons in transmitting electrochemical and the role of neurons in transmitting electrochemical impulsesimpulses

e. Students know the roles of sensory neurons, e. Students know the roles of sensory neurons, interneurons, and motor neurons in sensation, thought, interneurons, and motor neurons in sensation, thought, and responseand response

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The Nervous System: IntroductionThe Nervous System: Introduction

This system is made up of:This system is made up of: nervous tissue nervous tissue

BrainBrain

Spinal cord Spinal cord

Peripheral nervesPeripheral nerves

All other body systems may be present, but humans would essentially be nothing except for a body if not for the nervous system, which, by responding to stimulus from both the outside and inside of the body allows for proper, healthy function. The nervous system processes this information to help a person survive, either voluntarily (as in day-to-day actions) or involuntarily (as in constant breathing, digestion, or heart function). It is also essential for memory.

The Nervous System: NeuronsThe Nervous System: Neurons

Neurons are…Neurons are… Basic units of the nervous systemBasic units of the nervous system Control functions and movements Control functions and movements

of the bodyof the body Carry impulses (electrical signals Carry impulses (electrical signals

of the nervous system)of the nervous system)

The 3 kinds of neuronsThe 3 kinds of neurons Sensory neuronsSensory neurons

Responsible for bringing impulses detected by sense organs to the Responsible for bringing impulses detected by sense organs to the brain and spinal cordbrain and spinal cord

InterneuronsInterneurons

Act as a “middle-man” by relaying impulses between sensory and Act as a “middle-man” by relaying impulses between sensory and motor neuronsmotor neurons

Motor neuronsMotor neurons

Responsible for bringing impulses from the brain and spinal cord to Responsible for bringing impulses from the brain and spinal cord to the various muscles and glands of the bodythe various muscles and glands of the body

a neuron

The Nervous System: Nerve ImpulseThe Nervous System: Nerve ImpulseOnce an (electrical) nerve Once an (electrical) nerve impulse is initiated, it travels all impulse is initiated, it travels all the way in whatever direction it the way in whatever direction it is movingis moving

How it basically worksHow it basically works Sodium ions (a positive Sodium ions (a positive

charge) change the charge) change the charges of neuron’s cell’s charges of neuron’s cell’s membranesmembranes

The impulse is conveyed The impulse is conveyed along, the opposite charge along, the opposite charge on the outside of the on the outside of the membrane is turned membrane is turned negativenegative

Nerve impulses travel along neurons which are connected in long pathways called nerves. If there is damage, as shown in the neuron on the right side, then an impulse cannot be delivered.

The Nervous System: The Nervous System: Sectors of the SystemSectors of the System

Central Nervous SystemCentral Nervous System Made up of: brain, spinal cordMade up of: brain, spinal cord This is the main central system of the This is the main central system of the

nervous system and functions to deal nervous system and functions to deal with and work with informationwith and work with information

Peripheral Nervous SystemPeripheral Nervous System Made up of: all nerves and related Made up of: all nerves and related

cells (not including brain and spinal cells (not including brain and spinal cord)cord)

Sensory divisionSensory division Conveys impulses to the Conveys impulses to the

central nervous system from central nervous system from the body’s sense organsthe body’s sense organs

Motor divisionMotor division Conveys impulses to the Conveys impulses to the

muscles or glands that are muscles or glands that are sent from the central sent from the central nervous systemnervous system

Autonomic Nervous systemAutonomic Nervous system Deals with the involuntary functions Deals with the involuntary functions

and workings of the human bodyand workings of the human bodyThis graphic demonstrates the parts of the brain and the branches of the nervous system.

The Circulatory System: StandardsThe Circulatory System: Standards

Standards:Standards:– a. Students know how the complementary a. Students know how the complementary

activity of major body systems provides cells activity of major body systems provides cells with oxygen and nutrients and removes toxic with oxygen and nutrients and removes toxic waste products such as carbon dioxidewaste products such as carbon dioxide

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The Circulatory System: The Circulatory System: IntroductionIntroduction

This system is made up of:This system is made up of:– HeartHeart– Blood VesselsBlood Vessels– BloodBlood

Without the circulatory system constantly working, one would soon die. That is because all the cells in a human body need the oxygen and nutrients that the circulatory system brings to them. Also, the cells produce wastes including carbon dioxide that can only be effectively removed through the circulatory system.

Blood is pumped through the blood vessels by the heart to every reach of the body’s cells.

The Circulatory System: The HeartThe Circulatory System: The Heart The HeartThe Heart

– A hollow organA hollow organ– About the size of a person’s fistAbout the size of a person’s fist– Contracts (or beats) to pump blood to Contracts (or beats) to pump blood to

all of the various parts of the body via all of the various parts of the body via blood vessels.blood vessels.

– Completely surrounded by pericardium Completely surrounded by pericardium which is a sac of tissue that protects the which is a sac of tissue that protects the heartheart

How the Heart Beats (turn up the volume!)How the Heart Beats (turn up the volume!)– Also known as the pacemaker, the small Also known as the pacemaker, the small

group of cardiac muscle cells (in the right group of cardiac muscle cells (in the right atrium) called the sinoatrial node set the atrium) called the sinoatrial node set the entire heart’s beating rhythmentire heart’s beating rhythm

– The heart pumps blood faster or more slowly The heart pumps blood faster or more slowly depending on the body’s needs for depending on the body’s needs for oxygen/nutrientsoxygen/nutrients

Diagram labeling the various areas of the heart and the direction of blood flow.

An animation showing the direction of blood flows through the heart

The Circulatory System: Blood The Circulatory System: Blood VesselsVessels

ArteriesArteries- thick walled, large, hollow blood vessels that carry oxygen-rich - thick walled, large, hollow blood vessels that carry oxygen-rich blood (except for pulmonary arteries which carry oxygen-depleted blood blood (except for pulmonary arteries which carry oxygen-depleted blood from the heart to the lungs)from the heart to the lungs)

CapillariesCapillaries- tiny blood vessels in which the key workings of the circulatory - tiny blood vessels in which the key workings of the circulatory system is carried out; this is where cells exchange their waste products system is carried out; this is where cells exchange their waste products (including carbon dioxide) for nutrients, and most importantly, oxygen(including carbon dioxide) for nutrients, and most importantly, oxygen

VeinsVeins- valves in these blood vessels help to prevent gravity from getting in - valves in these blood vessels help to prevent gravity from getting in the way of conveying nutrient depleted blood back to the heartthe way of conveying nutrient depleted blood back to the heart

The Circulatory System:The Circulatory System: Paths of Paths of CirculationCirculation

Pulmonary circulationPulmonary circulation (contact w/ (contact w/ respiration)respiration)– Direction blood is pumped: from right Direction blood is pumped: from right

side of the heart to lungsside of the heart to lungs– At lungs, carbon dioxide is removed from At lungs, carbon dioxide is removed from

the blood and the oxygen is replenishedthe blood and the oxygen is replenished

Systemic circulationSystemic circulation– Oxygenated blood (that is back from the Oxygenated blood (that is back from the

lungs) returns to the lungs) returns to the left sideleft side of the of the heart and is pumped and released to the heart and is pumped and released to the rest of the bodyrest of the body

– The bod’s cells take in the oxygenated The bod’s cells take in the oxygenated and nutrient filled blood while putting and nutrient filled blood while putting out their carbon dioxide into the out their carbon dioxide into the bloodstreambloodstream

– This causes the blood to become oxygen This causes the blood to become oxygen depleted eventually depleted eventually

– The The oxygen depletedoxygen depleted blood makes its blood makes its rounds back to the rounds back to the right side of the right side of the heartheart for pulmonary circulation to begin for pulmonary circulation to begin again.again.

CLICK HERE to view animation on circulatory pathways as shown in image below

The Skeletal System: The Skeletal System: ComponentsComponents

This system is made up of:This system is made up of: BonesBones Other connective tissue such as:Other connective tissue such as:

cartilage – strong and flexible cartilage – strong and flexible connective tissue connective tissue

ligament – very tough and strong ligament – very tough and strong band of connective tissue that band of connective tissue that attaches to bones to keep them attaches to bones to keep them togethertogether

Femur, or thigh bone, as seen in an ultrasound image

Click on the walking skeleton above to view another animation that also realistically simulates human movement

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The Skeletal System: FunctionThe Skeletal System: Function FunctionsFunctions

Supports the body by Supports the body by providing a sturdy providing a sturdy frameworkframework

Provides protection for Provides protection for vital internal organs with, vital internal organs with, for example, the rib bonesfor example, the rib bones

Allows for movement when Allows for movement when muscles attached to them muscles attached to them as a result of jointsas a result of joints

Stores minerals Stores minerals Produces red blood cells in Produces red blood cells in

the marrow of the bonesthe marrow of the bones

Diagram of a human skeleton with the names of the bones labeled

The Skeletal System: Bone The Skeletal System: Bone StructureStructure

Diagram of a bone.

Bones have a hard, yet semi-flexible surface and are a frame for the human body. Inside the bone is a hollow region which contains bone

marrow, where red and most white blood cells and platelets are created.

The Skeletal System: JointsThe Skeletal System: Joints

Joints – site where bones Joints – site where bones attach to each otherattach to each other TypesTypes

Immovable Joints – (a.k.a. fixed Immovable Joints – (a.k.a. fixed joints) – these don’t allow motionjoints) – these don’t allow motion

Example: joints of the skullExample: joints of the skull Slightly Moveable Joints – allows Slightly Moveable Joints – allows

for some, but limited motionfor some, but limited motion Example: joints of the spine Example: joints of the spine

between the vertebraebetween the vertebrae Freely Moveable Joints – allows Freely Moveable Joints – allows

for motion in one or even more for motion in one or even more waysways

Example: knee joint, Example: knee joint, shoulder/hip jointshoulder/hip joint

This is a labeled diagram of a knee joint (one example of a freely movable joint

The Muscular System: StandardsThe Muscular System: Standards

Standards:Standards:– h. Students know the cellular and molecular basis of h. Students know the cellular and molecular basis of

muscle contraction, including the roles of actin, muscle contraction, including the roles of actin, myosin, Camyosin, Ca+2+2, and ATP, and ATP

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The Muscular System: IntroductionThe Muscular System: Introduction

This system consists of:This system consists of:– Muscle tissue (of the three different kinds) all throughout Muscle tissue (of the three different kinds) all throughout

the body which total up to more than 40% of the mass of the body which total up to more than 40% of the mass of an average humanan average human

Without the muscular system, humans could not move. The runner in the slide background could not run and much less hold a starting position. Though the skeleton gives a framework to human bodies, muscles are required to provide the movement factor.

The Muscular System: The Muscular System: Muscle Tissue 1 – Skeletal MusclesMuscle Tissue 1 – Skeletal Muscles

These are usually found These are usually found attached to bones and carry attached to bones and carry out the voluntary motions of a out the voluntary motions of a humanhuman

Consists of long, striped, Consists of long, striped, striated (meaning the striated (meaning the alternating dark and light alternating dark and light bands one would see going bands one would see going across the cell), across the cell), multinucleated cells – these multinucleated cells – these properties, especially the fact properties, especially the fact that the cells are narrow and that the cells are narrow and lengthy have caused them to lengthy have caused them to also be called also be called muscle fibersmuscle fibers

This image shows the front an back view of a person in terms of skeletal muscles

Skeletal muscles, as seen under microscope

The Muscular System: The Muscular System: Muscle Tissue 2 – Smooth MusclesMuscle Tissue 2 – Smooth Muscles

These usually carry out These usually carry out actions that are involuntary actions that are involuntary (uncontrollable by the (uncontrollable by the human’s will)human’s will)

Examples of where these Examples of where these are located: hollow are located: hollow structures such as stomach, structures such as stomach, intestines (both small and intestines (both small and large) and blood vesselslarge) and blood vessels

The cells that form smooth The cells that form smooth muscles have: single muscles have: single nucleus, no striations, and nucleus, no striations, and can function without nerve can function without nerve stimulationstimulation

These parts of the digestive system shown are all examples of locations where smooth muscles do their work

Smooth muscle, as seen under microscope

The Muscular System: The Muscular System: Muscle Tissue 3 – Cardiac MusclesMuscle Tissue 3 – Cardiac Muscles

The only place you can find The only place you can find these are in the heartthese are in the heart

Cardiac muscle cells: have Cardiac muscle cells: have striations, but only one striations, but only one nucleus and only nucleus and only occasionally two nucleioccasionally two nuclei

Obviously the cells must be Obviously the cells must be run in an involuntary manner run in an involuntary manner so as to keep the heart so as to keep the heart pumping and the person pumping and the person alivealive

Cardiac muscles, as seen under a microscope

Animation of a pumping heart-

powered by cardiac

muscles

The Muscular System: How Muscles ContractThe Muscular System: How Muscles ContractMuscle ContractionMuscle Contraction– How does a muscle fiber contract?How does a muscle fiber contract?

Simply put, the thin filaments called Simply put, the thin filaments called actinactin slide across and over the slide across and over the thicker filaments called thicker filaments called myosinmyosinATPATP that can be made by either that can be made by either cellular respiration or fermentation cellular respiration or fermentation on the part of cells, serves as the on the part of cells, serves as the fuel for powering muscle fiber fuel for powering muscle fiber contraction contraction

– From where does this contraction arise? From where does this contraction arise? (What triggers it?)(What triggers it?)

Calcium ions (CaCalcium ions (Ca+2)+2) are stimulated to are stimulated to be released in a muscle fiber by the be released in a muscle fiber by the impulse resulting from a certain impulse resulting from a certain neurotransmitter’s (called neurotransmitter’s (called acetylcholine) presenceacetylcholine) presenceThese calcium ions affect certain These calcium ions affect certain regulatory proteins that are regulatory proteins that are responsible for letting actin-myosin responsible for letting actin-myosin interaction happeninteraction happen

– When does the muscle relax?When does the muscle relax?When acetylcholine is no longer When acetylcholine is no longer present, or an enzyme blocks the present, or an enzyme blocks the passage of acetylcholine to the cellpassage of acetylcholine to the cell

The location of actin and myosin is demonstrated above

Animation above shows how the actin (the thinner lilac colored filaments) and myosin (thicker pink colored filaments) interact to contract and relax at the minute level.

The Integumentary System:The Integumentary System: ComponentsComponents

• This system is made up of:This system is made up of:– SkinSkin– HairHair– NailsNails– Various glandsVarious glands

This is a cross-section of skin as viewed under a microscope. Notice the hair and the hair follicle.

The surface of the skin is covered with pores.

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The Integumentary System: The Integumentary System: The SkinThe Skin

SkinSkin (largest component (largest component of integumentary system)of integumentary system)– Many Protective FunctionsMany Protective Functions

• Helps prevent infections, injuriesHelps prevent infections, injuries• Maintains body temperature- layer Maintains body temperature- layer

of fat beneath the skin layers of fat beneath the skin layers helps to insulate the bodyhelps to insulate the body

• Removes wastes from the body Removes wastes from the body passed out through the porespassed out through the pores

• Protection against ultraviolet sun Protection against ultraviolet sun radiation- significant amount of radiation- significant amount of radiation deflectedradiation deflected

– Contains sensory receptors that can Contains sensory receptors that can detect sensations from the outside detect sensations from the outside world (including heat, cold, pain, world (including heat, cold, pain, pressure, etc.)pressure, etc.)

Layer of skin as viewed under a microscope. Evident are the layers of skin: upper, lower, and the layer of fat beneath them.

The Integumentary System:The Integumentary System: Layers Layers of the Skin - 1of the Skin - 1

EpidermisEpidermis – the outermost, exposed layer of skin – the outermost, exposed layer of skin– 2 layers of epidermis2 layers of epidermis

– Inner layer- made up of living cells Inner layer- made up of living cells that divide quickly and push the older that divide quickly and push the older cells upwardscells upwards

• The older cells’ organelles The older cells’ organelles disintegrate; they begin to produce disintegrate; they begin to produce keratin, a tough fiber-like proteinkeratin, a tough fiber-like protein

– Outer layer- made up of the older cells Outer layer- made up of the older cells after they die (dead cells)after they die (dead cells)

• Very flexible yet tough and water-Very flexible yet tough and water-resistantresistant

• A new outer layer is exposed in the A new outer layer is exposed in the time of once every four or five time of once every four or five weeksweeks

– Does not contain blood vessels, so small Does not contain blood vessels, so small scratch or cut on the skin’s surface causes no scratch or cut on the skin’s surface causes no bleedingbleeding

– Contains melanocytes, cells that produce Contains melanocytes, cells that produce dark brown pigment called melanin dark brown pigment called melanin responsible for coloring people’s skinresponsible for coloring people’s skin

The epidermis is the uppermost layer of the skin and is exposed to the outside world.

The Integumentary System:The Integumentary System: Layers of Layers of the Skin - 2the Skin - 2

DermisDermis- inner layer of skin underneath - inner layer of skin underneath the epidermisthe epidermis– This layer contains…This layer contains…

- Collagen fibers - Sense - Collagen fibers - Sense organsorgans

- Blood vessels - Smooth - Blood vessels - Smooth musclesmuscles

- Nerve endings - Hair - Nerve endings - Hair folliclesfollicles

- Glands- Glands– Different types glands in the dermisDifferent types glands in the dermis

– Sweat glands: perspiration to Sweat glands: perspiration to cools body (sweat cools body (sweat evaporation removes heat)evaporation removes heat)

– Sebaceous (oil) glands: Sebaceous (oil) glands: makes oily substance makes oily substance (sebum) that spreads out on (sebum) that spreads out on the skin’s surface to help the skin’s surface to help maintain the epidermis’ maintain the epidermis’ (outer skin layer’s) pliable (outer skin layer’s) pliable and water-resistant qualitiesand water-resistant qualities

The dermis contains many glands, blood vessels, and

other structures.

- Function of Blood Vessels - Function of Blood Vessels - widen to allow more - widen to allow more conveyance of heat from conveyance of heat from within the body in warm or within the body in warm or hot conditions and narrow hot conditions and narrow to prevent excessive heat to prevent excessive heat loss on cold daysloss on cold days

The Integumentary System:The Integumentary System:Hair and NailsHair and Nails

• Hair and Nails (both formed by keratin)Hair and Nails (both formed by keratin)– HairHair

• Protects body in variety of ways including from sun’s Protects body in variety of ways including from sun’s UV (Ultraviolet) rays, heat, cold, and dirt/dustUV (Ultraviolet) rays, heat, cold, and dirt/dust

– NailsNails• Protect the ends of people’s fingers and toesProtect the ends of people’s fingers and toes

On the left are pictures of nails which demonstrate their distinct and necessary location.

To the right is a diagram of a hair in its hair follicle

The Respiratory System: The Respiratory System: StandardsStandards

Standards:Standards: a. Students know how the complementary a. Students know how the complementary

activity of major body systems provides cells activity of major body systems provides cells with oxygen and nutrients and removes toxic with oxygen and nutrients and removes toxic waste products such as carbon dioxidewaste products such as carbon dioxide

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The Respiratory System:The Respiratory System:IntroductionIntroduction

This system is made up of:This system is made up of: NoseNose PharynxPharynx LarynxLarynx TracheaTrachea BronchiBronchi LungsLungs

What is the main purpose of human’s having a respiratory system?

Basically, the respiratory system allows humans to exchange carbon dioxide, the waste product of many body functions, for oxygen, which powers many human processes.

The Respiratory System: The Respiratory System: The Process of The Process of

Breathing/Respiration - 1Breathing/Respiration - 1 How a person breathes to take in air and exhales How a person breathes to take in air and exhales

to get rid of “used” airto get rid of “used” air The chest cavity containing the lungs is The chest cavity containing the lungs is

completely sealed up, so when the diaphragm, completely sealed up, so when the diaphragm, a long, flat muscle beneath the cavity contracts a long, flat muscle beneath the cavity contracts (downward), like a vacuum, a person (downward), like a vacuum, a person immediately sucks in air into their lungsimmediately sucks in air into their lungs

To exhale, the diaphragm relaxes (upward) and To exhale, the diaphragm relaxes (upward) and thereby forces air out of the lungsthereby forces air out of the lungs

Let’s follow the journey of breathed air:Let’s follow the journey of breathed air: Upper Respiratory SystemUpper Respiratory System

1. enter through the nose1. enter through the nose 2. passes through the pharynx (tube for both food 2. passes through the pharynx (tube for both food

and air)and air) 3. goes through pharynx where the vocal cords 3. goes through pharynx where the vocal cords

are located and into the trachea toward the lungsare located and into the trachea toward the lungs

All along the way, measures are taken to All along the way, measures are taken to ensure the cleanest air reaches the lungsensure the cleanest air reaches the lungs

Air must be slightly heated, made moister, Air must be slightly heated, made moister, and screenedand screened

Dust particles filtered out by small Dust particles filtered out by small hairshairs

Mucus produced to trap particles and Mucus produced to trap particles and make the air moistmake the air moist

The Upper Respiratory System

CLICK HERE and scroll down to view an animation of how the diaphragm works

The Respiratory System: The Respiratory System: The Process of The Process of

Breathing/Respirations - 2Breathing/Respirations - 2 Let’s continue following the journey of Let’s continue following the journey of

breathed air:breathed air: 4. the air flows down the trachea4. the air flows down the trachea 5. then it reaches the bronchi, two 5. then it reaches the bronchi, two

large tube-like passageways, each large tube-like passageways, each of which leads to one of the two of which leads to one of the two lungslungs

6. the air continues on into smaller 6. the air continues on into smaller and smaller passageways called and smaller passageways called bronchiolesbronchioles

7. the air reaches the alveoli, the 7. the air reaches the alveoli, the millions of minute and bunched millions of minute and bunched together air sacs (alveoli are air together air sacs (alveoli are air sacs which are seemingly covered sacs which are seemingly covered in nets of tiny capillariesin nets of tiny capillaries

8. at the alveoli, an exchange of 8. at the alveoli, an exchange of gases occurs, which will be gases occurs, which will be explained in the next slide.explained in the next slide.

Notice how the lungs contain many tubes called bronchioles that branch out from the bronchi

The Respiratory System:The Respiratory System:How oxygen taken in; carbon How oxygen taken in; carbon

dioxide removeddioxide removed This exchange of gases is This exchange of gases is

carried out at the alveoli (small carried out at the alveoli (small sacs of air)sacs of air) In a normal, properly In a normal, properly

functioning healthy lung functioning healthy lung there exists around 350 there exists around 350 million of these alveolimillion of these alveoli

How is oxygen switched with How is oxygen switched with carbon dioxide?carbon dioxide?

The carbon dioxide The carbon dioxide diffuses across the diffuses across the alveoli’s membrane and alveoli’s membrane and into the air sac to be into the air sac to be exhaledexhaled

The inhaled oxygen in the The inhaled oxygen in the alveoli’s air sac diffuses alveoli’s air sac diffuses across the membranes across the membranes the other way- into the the other way- into the bloodstream to be bloodstream to be circulated throughout the circulated throughout the body body

Above is a an alveoli. The (blue) blood arriving is oxygen-deprived. At the alveoli, oxygen diffuses into the blood and carbon dioxide diffuses out. This leaves the blood replenished with oxygen as it leaves (red).

The Excretory System: StandardsThe Excretory System: Standards

Standards:Standards:– a. Students know how the complementary activity a. Students know how the complementary activity

of major body systems provides cells with oxygen of major body systems provides cells with oxygen and nutrients and removes toxic waste products and nutrients and removes toxic waste products such as carbon dioxidesuch as carbon dioxide

– g. Students know the homeostatic role of the g. Students know the homeostatic role of the kidneys in the removal of nitrogenous wastes and kidneys in the removal of nitrogenous wastes and the role of the liver in blood detoxification and the role of the liver in blood detoxification and glucose balanceglucose balance

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The Excretory System: IntroductionThe Excretory System: Introduction

This system is made up of the:This system is made up of the:– SkinSkin– LungsLungs– KidneysKidneys (main organs of the (main organs of the

excretory system)excretory system)– And the organs that are And the organs that are

related/connected in function to related/connected in function to themthem

Why do we need an excretory Why do we need an excretory system? system? – Human body needs this system to Human body needs this system to

carry out carry out homeostasishomeostasis, (process , (process constantly being carried with goal constantly being carried with goal of an internal balance within the of an internal balance within the body. body.

– excretory system promotes this excretory system promotes this healthy balance by removing from healthy balance by removing from the body toxic and/or harmful the body toxic and/or harmful waste in various ways as waste in various ways as discussed in the following slides…discussed in the following slides…

The image above shows oxygen and nutrients absorbed by cells, while wastes are passed out to be taken care of by the excretory system. Next to it is a chart which matches wastes with its various associations.

The Excretory System: Skin and LungsThe Excretory System: Skin and Lungs

SkinSkin– Excretes sweat out of the body Excretes sweat out of the body

through its numerous sweat poresthrough its numerous sweat pores Contained in the sweat is:Contained in the sweat is:

– extra or excess water and extra or excess water and saltsalt

– a little urea (a toxic a little urea (a toxic compound that forms compound that forms resulting from amino acids resulting from amino acids being used for energy)being used for energy) The red arrow points to a sweat

gland which secretes waste, when necessary, through the sweat pore at the surface.

Above is an image depicting the lungs, where wastes as carbon dioxide are removed from the bloodstream.

LungsLungs– The lungs excrete carbon dioxide, The lungs excrete carbon dioxide,

which is produced as a waste which is produced as a waste product resulting from energy product resulting from energy capturing from compounds in foodscapturing from compounds in foods

The Excretory System: Kidneys The Excretory System: Kidneys

The two kidneys are the main organs of the excretory The two kidneys are the main organs of the excretory system. What do they do?system. What do they do?

– Waste-filled blood flows into the kidney Waste-filled blood flows into the kidney through renal artery (arteries carry through renal artery (arteries carry blood away from heart)blood away from heart)

– In kidney, the wastes including excess In kidney, the wastes including excess water, salts, urea filtered outwater, salts, urea filtered out

– The cleansed blood then continues to The cleansed blood then continues to circulate onward, leaving the kidney circulate onward, leaving the kidney through the renal veinthrough the renal vein

– Wastes that include urea, salts, water, Wastes that include urea, salts, water, and others flow down the ureters to the and others flow down the ureters to the bladder and then are released from the bladder and then are released from the body in urine through the urethrabody in urine through the urethra

Above at the left is a labeled diagram of a kidney, where blood filtering takes place.

At the right is the actual urinary system which shows the location of the two kidneys and other components.

The Excretory System: The Excretory System: Homeostatic Function of KidneysHomeostatic Function of Kidneys

Those functions are extremely important because a Those functions are extremely important because a person can be in a fatal condition in the event of damage person can be in a fatal condition in the event of damage or disease affecting the kidneysor disease affecting the kidneys

In that case, one would need to either get a new In that case, one would need to either get a new transplanted kidney from a donor (the ideal, but difficult transplanted kidney from a donor (the ideal, but difficult to get solution) or undergo dialysis. A kidney dialysis to get solution) or undergo dialysis. A kidney dialysis machine, though time consuming for a patient, works machine, though time consuming for a patient, works similar to a kidney and cleanses blood to keep the person similar to a kidney and cleanses blood to keep the person alive.alive.

So, in exactly what ways do the kidneys maintain the stable So, in exactly what ways do the kidneys maintain the stable internal balance achieved by hinternal balance achieved by homeostasisomeostasis?? They… They…– Maintain and control the amount of water in the blood which directly Maintain and control the amount of water in the blood which directly

correlates with blood volumecorrelates with blood volume– Maintain a specific pH for bloodMaintain a specific pH for blood– Prevents waste from accumulating by taking them out of the bloodstream Prevents waste from accumulating by taking them out of the bloodstream

and then out of the bodyand then out of the body

Man hooked up to kidney dialysis machine

The Endocrine System: StandardsThe Endocrine System: Standards

Standards:Standards: c. Students know how feedback loops in the nervous c. Students know how feedback loops in the nervous

and endocrine systems regulate conditions in the and endocrine systems regulate conditions in the bodybody

g. Students know the homeostatic role of the kidneys g. Students know the homeostatic role of the kidneys in the removal of nitrogenous wastes and the role of in the removal of nitrogenous wastes and the role of the liver in blood detoxification and glucose balancethe liver in blood detoxification and glucose balance

i. Students know how hormones (including digestive, i. Students know how hormones (including digestive, reproductive, osmoregulatory) provides internal reproductive, osmoregulatory) provides internal feedback mechanisms for homeostasis at the cellular feedback mechanisms for homeostasis at the cellular level and in whole organismslevel and in whole organisms

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The Endocrine System: IntroductionThe Endocrine System: Introduction

This system is made up of:This system is made up of: Hormone producing, Hormone producing,

ductless glands ductless glands

The endocrine system’s glands are illustrated at the right. These glands are necessary to control the rate of metabolism of a body, rate or growth, and sexual development/ function. All are controlled by a feedback mechanism that maintains the balanced condition of homeostasis in response to both outside and inside stimulus.

The Endocrine System: The Endocrine System: Feedback Mechanisms Control FunctionFeedback Mechanisms Control Function

Hypothalamus, a part of the brain, will Hypothalamus, a part of the brain, will sense if there is excessive or too little sense if there is excessive or too little amounts of hormones in the blood amounts of hormones in the blood and signal the pituitary glands to and signal the pituitary glands to produce more or less of trophic, or produce more or less of trophic, or gland-stimulating, hormonegland-stimulating, hormone If a gland is making too much of a If a gland is making too much of a

hormone:hormone: Pituitary gland signaled by Pituitary gland signaled by

hypothalamus to produce hypothalamus to produce less less trophic hormonetrophic hormone to normalize to normalize situationsituation

If a gland is making too little of a If a gland is making too little of a hormone:hormone: Pituitary gland signaled by Pituitary gland signaled by

hypothalamus to produce hypothalamus to produce more trophic hormonemore trophic hormone to to normalize situationnormalize situation

This flow chart demonstrates one of the feedback systems that helps control the amounts of hormone in response to cold.

The Endocrine System:The Endocrine System: Glands and Parts (1)Glands and Parts (1)

Pituitary GlandPituitary Gland Connected to Connected to

hypothalamushypothalamus Nine different hormones Nine different hormones

are secreted by this are secreted by this gland- these function to gland- these function to maintain bodily functions maintain bodily functions and keep under control and keep under control some of the other glands some of the other glands that are part of the that are part of the endocrine systemendocrine system

Hypothalamus (NOT A Hypothalamus (NOT A GLAND)GLAND) Part of the brain that Part of the brain that

controls the functions controls the functions and actions of the and actions of the pituitary glandpituitary gland

Location and parts of the pituitary gland and hypothalamus

The Endocrine System:The Endocrine System: Glands and Parts (2) Glands and Parts (2)

Thyroid GlandThyroid Gland Controls and maintains Controls and maintains

body metabolismbody metabolism Produces thyroxine, a Produces thyroxine, a

hormone, in a carefully hormone, in a carefully controlled manner to controlled manner to maintain level of maintain level of metabolism of (most of metabolism of (most of the) cells all around the the) cells all around the bodybody

Parathyroid GlandsParathyroid Glands There are four of these There are four of these

glandsglands Produce hormones, along Produce hormones, along

with the thyroid gland, that with the thyroid gland, that regulate calcium levels in regulate calcium levels in the blood for homeostasisthe blood for homeostasis

The location of the thyroid and parathyroid glands in the neck.

The Endocrine System:The Endocrine System: Glands and Parts (3) Glands and Parts (3)

Adrenal GlandsAdrenal Glands Responsible for Responsible for

regulating some kidney regulating some kidney function and secreting function and secreting hormones that prepare a hormones that prepare a person for stressful person for stressful situations (which may situations (which may call for a, for instance, call for a, for instance, “fight of flight” response“fight of flight” response

Adrenal gland as seen under high magnification

The adrenal glands are located right on top of the kidneys.

The Endocrine System:The Endocrine System: Glands and Parts (3) Glands and Parts (3)

Pancreas (NOT A GLAND)Pancreas (NOT A GLAND) Secretes insulin, Secretes insulin,

glucagon to maintain glucagon to maintain healthy blood sugar (or healthy blood sugar (or glucose) levelsglucose) levels

Reproductive Glands (Gonads)Reproductive Glands (Gonads) MaleMale

Testes- make spermTestes- make sperm FemaleFemale

Ovaries- make eggs (also Ovaries- make eggs (also known as ova)known as ova)

The pancreas’ location is shown here. (It also has functions in the digestive system as shown by its proximities and connections.

The Endocrine System: LiverThe Endocrine System: Liver Liver – some of its functions allow it to be considered Liver – some of its functions allow it to be considered

a member of the endocrine systema member of the endocrine system Blood detoxificationBlood detoxification

Liver gets blood from the intestines that Liver gets blood from the intestines that contains many nutrients, but along with that contains many nutrients, but along with that toxins and chemicals that are potentially toxins and chemicals that are potentially harmfulharmful

Before this blood can re-enter the circulatory Before this blood can re-enter the circulatory system, the liver cleanses out those toxins system, the liver cleanses out those toxins and therefore plays a key role in cleaning the and therefore plays a key role in cleaning the bloodblood

This is why liver failure or poor function is This is why liver failure or poor function is devastating to healthy function; the liver devastating to healthy function; the liver prevents waste accumulationprevents waste accumulation Glucose balanceGlucose balance

When there is too much glucose in the blood then the body’s cells need, the liver When there is too much glucose in the blood then the body’s cells need, the liver converts the glucose into glycogen, which it stores converts the glucose into glycogen, which it stores

When glucose is needed, then, (under stimulation from hormones), the liver will When glucose is needed, then, (under stimulation from hormones), the liver will reconvert the glycogen back into glucose and release the glucose back into the reconvert the glycogen back into glucose and release the glucose back into the bloodstream for cell’s usebloodstream for cell’s use

Other balancing actsOther balancing acts Controlling and maintaining other items, such as amino acidsControlling and maintaining other items, such as amino acids Works constantly to clear poisonous substances such as alcoholWorks constantly to clear poisonous substances such as alcohol Makes proteinsMakes proteins

Anatomy of the liver

The Digestive System: The Digestive System: StandardsStandards

Standards:Standards: a. Students know how the complementary activity of a. Students know how the complementary activity of

major body systems provides cells with oxygen and major body systems provides cells with oxygen and nutrients and removes toxic waste products such as nutrients and removes toxic waste products such as carbon dioxidecarbon dioxide

f. Students know the individual functions and sites of f. Students know the individual functions and sites of secretion of digestive enzymes (amylases, secretion of digestive enzymes (amylases, proteases, nucleases, lipases), stomach acid, and proteases, nucleases, lipases), stomach acid, and bile saltsbile salts

MENUMENU

The Digestive System: ComponentsThe Digestive System: Components

This system is made up of:This system is made up of: MouthMouth EsophagusEsophagus StomachStomach LiverLiver PancreasPancreas GallbladderGallbladder Small and large intestinesSmall and large intestines

The main function of the digestive system is to change the foods humans eat into much smaller molecules that cells can actually absorb and use.

The following slides takes this process step by step by location…

The Digestive System -The Digestive System - The Process of Digesting: The Process of Digesting:

# 1 # 1 The MouthThe Mouth

Mouth – the first step of the digestive system Mouth – the first step of the digestive system

TeethTeeth Carry out the “physical” work of initial digestionCarry out the “physical” work of initial digestion They are bones that have their bases attached to They are bones that have their bases attached to

the jaw bone, but are much stronger than regular the jaw bone, but are much stronger than regular bones so as to give them the ability to grind up bones so as to give them the ability to grind up food as thoroughly as possible into small piecesfood as thoroughly as possible into small pieces

Salivary GlandsSalivary Glands Controlled by the nervous system to secrete saliva Controlled by the nervous system to secrete saliva

that aids in moistening the food to help the person that aids in moistening the food to help the person chew easierchew easier

Saliva contains amylase- enzyme that breaks down Saliva contains amylase- enzyme that breaks down starchstarch

Saliva also contains lysozyme- enzyme that counters Saliva also contains lysozyme- enzyme that counters infection by destroying bacteria’s cell wallsinfection by destroying bacteria’s cell walls

The Digestive System -The Digestive System - The Process of Digesting: The Process of Digesting:

# 2 # 2 The EsophagusThe Esophagus

After being chewed up, a clump of After being chewed up, a clump of food is then called a bolusfood is then called a bolus

This bolus is pushed down into the This bolus is pushed down into the throat and down into the throat and down into the esophagus esophagus

In the esophagus, the bolus is not In the esophagus, the bolus is not gravitationally drawn toward the gravitationally drawn toward the stomach, but instead, the stomach, but instead, the esophagus carries out esophagus carries out contractions called peristalsis, contractions called peristalsis, which gradually squeezes the which gradually squeezes the bolus down into the stomachbolus down into the stomach

The multi-image graphic at the right shows the relative location of the esophagus and depicts how peristalsis works

To see a short video following a bolus down the esophagus into the stomach, click here and click on the large image on the page.

The Digestive System -The Digestive System - The Process of Digesting: The Process of Digesting:

# 3 # 3 The StomachThe Stomach The food that has been consumed now enters the stomach which The food that has been consumed now enters the stomach which

continues digesting itcontinues digesting it Chemical DigestionChemical Digestion

The lining of the stomach containsThe lining of the stomach contains Glands that make Glands that make mucusmucus that function to lubricate and thus that function to lubricate and thus

prevent damage to the stomach wallprevent damage to the stomach wall Glands that make Glands that make hydrochloric acidhydrochloric acid (or stomach acid), a very (or stomach acid), a very

acidic acid which thereby makes the stomach a very acidic acidic acid which thereby makes the stomach a very acidic place and the enzyme place and the enzyme nucleasenuclease, which works on breaking , which works on breaking down nucleic acid into smaller nucleotidesdown nucleic acid into smaller nucleotides

Presence of hydrochloric acid activates Presence of hydrochloric acid activates pepsinpepsin, an enzyme , an enzyme that, with hydrochloric acid, begins the process of digesting that, with hydrochloric acid, begins the process of digesting proteinsproteins

Mechanical DigestionMechanical Digestion Since the stomach is a hollow muscular organ, it is able to churn Since the stomach is a hollow muscular organ, it is able to churn

the fluids and food contents within itthe fluids and food contents within it This produces chyme, the mixture of such stomach fluids and foodThis produces chyme, the mixture of such stomach fluids and food After about 1-2 hours, the pyloric valve, which, when closed After about 1-2 hours, the pyloric valve, which, when closed

prevents stomach content from spilling into the small intestine prevents stomach content from spilling into the small intestine prematurely, opens and chyme can then enter the small intestinesprematurely, opens and chyme can then enter the small intestines

A labeled stomach. Notice the multiple strong muscle layers/

The Digestive System -The Digestive System - The Process of Digesting: The Process of Digesting:

# 4 # 4 The Pancreas The Pancreas

From the stomach, chyme enters the From the stomach, chyme enters the duodenum, the first section of small intestines duodenum, the first section of small intestines where a significant amount of chemical where a significant amount of chemical digestion occurs:digestion occurs: The PancreasThe Pancreas

Is a gland that makesIs a gland that makes Enzymes that help disintegrate Enzymes that help disintegrate

carbohydrates, nucleic acids, carbohydrates, nucleic acids, proteins, lipids – these include…proteins, lipids – these include…

Amylase, which works on Amylase, which works on breaking down starchbreaking down starch

Protease, which works on Protease, which works on breaking down proteinbreaking down protein

Trypsin (an example of a Trypsin (an example of a protease), which works on protease), which works on breaking down proteinbreaking down protein

Lipase, which works on breaking Lipase, which works on breaking down fatdown fat

This diagram shows the location of the pancreas. Ducts in the pancreas pass enzymes into the duodenum

The Digestive System -The Digestive System - The Process of Digesting: The Process of Digesting:

# 4 (continued) # 4 (continued) The LiverThe Liver

From the stomach, chyme enters the From the stomach, chyme enters the duodenum, the first section of small duodenum, the first section of small intestines where a significant amount of intestines where a significant amount of chemical digestion occurs:chemical digestion occurs: The LiverThe Liver

Makes bile salts (bile is a fluid that Makes bile salts (bile is a fluid that contains a lot of lipids and salts, contains a lot of lipids and salts, which separates, and dissolves which separates, and dissolves droplets of fat so that enzymes droplets of fat so that enzymes can get to them)can get to them)

Bile salts are then stored in the Bile salts are then stored in the gall bladder to be released into gall bladder to be released into the duodenum through the bile the duodenum through the bile ductduct

The liver and its generalized processes are depicted above.

Small IntestinesSmall Intestines Approximately three meters long- a lot longer compared to Approximately three meters long- a lot longer compared to

the initial duodenumthe initial duodenum When chyme enters this organ, chemical digestion is pretty When chyme enters this organ, chemical digestion is pretty

much completemuch complete Villi, tiny protruding structures, absorb the nutrient Villi, tiny protruding structures, absorb the nutrient

molecules in the chyme as the muscles contract to move molecules in the chyme as the muscles contract to move the chyme alongthe chyme along

The capillaries in the villi absorb the materials that resulted The capillaries in the villi absorb the materials that resulted from carbohydrates and protein digestionfrom carbohydrates and protein digestion

Some fatty acids and undigested fat molecules are also Some fatty acids and undigested fat molecules are also absorbed into lacteals, which are lymph vesselsabsorbed into lacteals, which are lymph vessels

Large IntestinesLarge Intestines What was once food is now nutrient-less matter that passes What was once food is now nutrient-less matter that passes

into the large intestinesinto the large intestines Through the large intestines, solid waste (unneeded by the Through the large intestines, solid waste (unneeded by the

body or excreted if recognized to be harmful or toxic) is body or excreted if recognized to be harmful or toxic) is passed out of the bodypassed out of the body

The Digestive System -The Digestive System - The Process of Digesting: The Process of Digesting:

# 5 # 5 The IntestinesThe Intestines (Small and Large)(Small and Large)

This is an electron micrograph of villi in the small intestines

Location of the small and large intestines

The Reproductive SystemThe Reproductive System

The primary function of the reproductive system is to help ensure The primary function of the reproductive system is to help ensure the continual survival of a species, in this case, humansthe continual survival of a species, in this case, humans

What makes this system one of the most, if not the most vital system for the human race? The reproductive system is responsible for making, holding, and releasing gametes, specialized cells. The male gamete is called the sperm and the female gamete is called the egg. When fertilization occurs, that is, a sperm successfully makes contact with an egg and enters it to fertilize it, a zygote is produced. From the zygote, the single fertilized egg, a baby soon develops.

MENUMENU

The Reproductive System: HormonesThe Reproductive System: Hormones Primary reproductive organs are called Primary reproductive organs are called gonadsgonads

• In the Male they are the In the Male they are the testestestes Releases male sex hormone: testosteroneReleases male sex hormone: testosterone

• Produces spermProduces sperm• Promotes male physical characteristics and Promotes male physical characteristics and

developmentdevelopment

• In the Female they are the In the Female they are the ovariesovaries Releases female sex hormones: estrogen, progesteroneReleases female sex hormones: estrogen, progesterone

• EstrogenEstrogen Needed for eggs to developNeeded for eggs to develop Promotes female physical characteristics and Promotes female physical characteristics and

developmentdevelopment• ProgesteroneProgesterone

Readies the uterus for developing embryoReadies the uterus for developing embryo

Sperm cells

Egg cells

The Reproductive System: FertilizationThe Reproductive System: Fertilization

If an egg is located in a female’s If an egg is located in a female’s Fallopian tube (there are two of Fallopian tube (there are two of these connected to the upper these connected to the upper region of the uterus) chances are region of the uterus) chances are good that it will be fertilized in the good that it will be fertilized in the presence of spermpresence of sperm

Only about 1% of sperm ever reach Only about 1% of sperm ever reach the egg cell and only one may the egg cell and only one may fertilize the egg cellfertilize the egg cell

As soon as the single sperm As soon as the single sperm attaches to the egg, it enters and attaches to the egg, it enters and conjoins its nucleus with the egg’s conjoins its nucleus with the egg’s (after the breakdown of the nuclear (after the breakdown of the nuclear membranes of both gametes)membranes of both gametes)

Now the egg has been fertilized. Now the egg has been fertilized.

This is an electron micrograph showing that several sperm have succeeded in reaching the egg. However, only one will be successful in actually fertilizing the egg.

The Reproductive System: The Reproductive System: Embryonic DevelopmentEmbryonic Development

From the singled celled zygote, or fertilized egg, From the singled celled zygote, or fertilized egg, the cell continues to divide. the cell continues to divide. In the animation to In the animation to the right, the first six weeks from fertilization are the right, the first six weeks from fertilization are depicted.depicted. (If the animation is not working click on (If the animation is not working click on it.) The wall-like place that the embryo is seen it.) The wall-like place that the embryo is seen implanting itself is the uterine wall of the pregnant implanting itself is the uterine wall of the pregnant woman.woman.

Eventually, after about 9 months following Eventually, after about 9 months following fertilization, the fetus (what the embryo is called fertilization, the fetus (what the embryo is called after more than eight weeks) has been prepared after more than eight weeks) has been prepared physically for birth.physically for birth.

Contractions of the uterus, in which the baby has Contractions of the uterus, in which the baby has been in for almost all of the woman’s pregnancy, been in for almost all of the woman’s pregnancy, forces the baby out into the world to begin its life forces the baby out into the world to begin its life as a new human being.as a new human being.

A newborn baby

Early development - from zygote to (early) embryo

The Immune Response System: Standards Standards:

Organisms have a variety of mechanisms to combat disease. As a basis for understanding the human immune response:

a. Students know the role of the skin in providing nonspecific defenses against infection

b. Students know the role of antibodies in the body’s response to infection c. Students know how vaccination protects an individual from infectious

diseases d. Students know there are important differences between bacteria and

viruses with respect to their requirements for growth and replication, the body’s primary defenses against bacterial and viral infection, and effective treatments of these infections

e. Students know why an individual with a compromised immune system (for example, a person with AIDS) may be unable to fight off and survive infections by microorganisms that are usually benign

f. Students know the roles of phagocytes, B-lymphocytes, and T-lymphocytes in the immune system

MENUMENU

The Immune Response System: Components

This system is made up of: The cells and proteins that work together to protect the body from

Any suspected microorganisms (examples: viruses, fungi, bacteria) that may be harmful and infectious

Main Body Structures (External) Eyes Nose Mouth Respiratory tract Stomach and intestines Genitourinary system Skin

The Immune System: Nonspecific (or Innate) Immunity

This is the nonspecific and quickly- responding immune response that humans are born with and includes..

Barriers (both chemical and physical) The skin is the first defense against pathogens Inflammatory response occurs if pathogen gets

past skin Blood vessels by open wound enlarge to

allow the white blood cells to leak into the tissue that is infected

Phagocytes White blood cells that engulf a recognized

foreign body and then digest the foreign body with enzymes (within the cell’s lysosomes)

Interferons Virus-resistant proteins (acts to slow virus to

allow more time for the immune system to respond)

If the skin, a major defense, is broken the inflammatory response takes effect…

Notice how the inflammation functions to allow pathogen and foreign body fighting white blood cells into the affected tissue.

The Immune System:Humoral Immunity Provides bacterial defense

Recognition process: since there are so many varieties of B-lymphocytes, only some will be stimulated by antigens.

T-lymphocytes help to keep a control on this process to ensure workings

These T-lymphocytes, or helper T cells help B-lymphocytes, or B cells become antibody making plasma cells which produce many antibodies to counter the bacteria

Antibodies, in the future, will respond to the same antigen to disable them

A close-up view of a T-lymphocyte

Phagocytes engulfing bacterium to initiate the humoral immunity process.

The Nervous System: Vaccination

This is one of the ways a person can strengthen their immune systems to protect them better

How it works Weakened or dead microorganisms

(responsible for causing a specific disease such as measles or influenza, etc.) are introduced to the body

Those microorganisms are not strong enough to cause disease, but do trigger an immune response that makes antibodies against the microorganism

In a future exposure to the microorganism, those antibodies will be activated and counter the microorganism effectively

Vaccination is important because it helps a human’s body be better prepared for countering harmful disease.

The Immune System:Virus vs. Bacteria

Virus Are not alive, parasitic (depend

on host for survival, replication Can lay dormant and be

reactivated Replicates by using a cell it has

entered, cell bursts and many more viruses emerge

Body’s primary defense: white cells (macrophages) engulf viral particles, lymphocytes make antibodies countering virus

Effective treatment: more difficult to fight a virus caused disease than bacterial; help patient’s symptoms and hope immune system strong enough (in some cases), immunization (sometimes)

Bacteria Single-cell microorganisms (so are alive) Reduction (sometimes full) in strength

after time Some are beneficial to humans Multiply and live in warm, wet conditions

and cannot move on their own Reproduce much less rapidly then viruses

because, as cells, they can only double in a given time period

Body’s primary defense: enzymes and acid which kill bacteria, white blood cells engulf them, antibodies

Effective treatment: improve hygiene, immunization

For Venn Diagram (that is not made by this powerpoint author) view the next slide…

virus bacteria

Venn Diagram: Comparing Virus and Bacteria

The Immune System:Disorders and Consequences

Allergies Allergy inducing antigen attach to

mast cells, (which are common in the body’s nasal passage)

The mast cells are then stimulated to make histamines, a chemical that causes the irritations that result from allergies.

Autoimmune Disease Occurs when the immune system

mistakes the bodies cells for its enemies

AIDS (Acquired Immune Deficiency Syndrome) which makes person’s immune system dysfunctional; they will contract illnesses normally easily fended off by healthy immune system

In this case, the women’s allergies are perhaps caused by allergens in her pet’s hair.

Structure of an HIV virus which is the cause of AIDS.

The Human Body: Systems MenuNervous SystemNervous System

Circulatory SystemCirculatory System

Skeletal SystemSkeletal System

Muscular SystemMuscular System

Reproductive SystemReproductive System

Digestive SystemDigestive System

Excretory SystemExcretory System

Respiratory SystemRespiratory System

Integumentary SystemIntegumentary System

Immune SystemImmune System

Endocrine SystemEndocrine System

EXITEXITAre you sure?Are you sure?YesYes NoNo

THE ENDTHE END