How Humans WorkLisa Shue

Period 6

Table of Systems

Nervous Integumentary Respiratory Circulatory Digestive Skeletal Excretory Reproductive Endocrine Muscular Immune

Nervous System What is it made of? brain, spinal cord, and peripheral nerves.

What does it do? Controls the body in response to internal and external environments.

Standards? b. Students know how the nervous system mediates communication between

different parts of the body and the body's interactions with the environment. c. Students know how feedback loops in the nervous and endocrine systems regulate

conditions in the body. d. Students know the functions of the nervous system and the role of neurons in

transmitting electrochemical impulses. e. Students know the roles of sensory neurons, interneurons, and motor neurons in

sensation, thought, and response.

2 Main Sections

The nervous system is divided into 2 sections: the central nervous system (brain and spinal cord) and peripheral nervous system. (everything outside the central nervous sys).

The CNS – central nervous system – is the control center for the body. This part of the nervous system sends, analyzes, and processes messages to and from the rest of the body. The spinal cord is the way that the brain controls and sends information to the rest of the body.

central nervous system->

The PNS – peripheral nervous system –

is the part of the nervous system where it comes

into contact with the environment. It is whatever

Is not in the CNS.

2 Parts of the Peripheral System.

Somatic nervous system: controls VOLUNTARY actions. Motor neurons send information from the brain and spinal cord to control actions like moving legs and hands. These are all actions that occur under conscious control.-sometimes- there are rapid responses that happen so quick, people don’t think about it before movement takes place. This is a reflex: when neurons in the spinal cord automatically make certain motor neurons take action. Reflexes keep a person from harm. Example: if you touch something hot, you automatically back off so you do not get burned!

On the other hand…

The autonomic nervous system controls AUTOMATIC activities – like the beating of the heart and the person’s breathing. This system help keeps the body alive without making the person to always have to think about it

How the Nervous System Works

Neurons are essential in this system. They send impulses – messages in the form of electric signals – to the rest of the body.

Sensory neurons (afferent): send messages from sense organs TO the central nervous system. This is how humans sense their surroundings. There are pain receptors, thermoreceptors - temperature, mechanoreceptors –

sounds, touch, and motion, chemoreceptors – chemicals, tastes, and photoreceptors - light.

Motor neurons (efferent): bring messages FROM the brain and spinal cord to muscles and glands. This is how people’s muscles and glands take action.

Interneurons: connect the two types of neurons and send impulses between the two.

What are Neurons Made of? Neurons have a cell body which has the nucleus and most of the cytoplasm.

NEURONS HAVE DENDRITES AND AXIONS. Dendrites carry impulses to the cell body of the neuron. Axons carry impulses away from the cell body.

Some neurons have a membrane called the myelin sheath around the axon. The membrane has gaps in it, which are called nodes. Because of this, when an impulse is sent, the impulse jumps from node to node on the axon membrane RATHER THAN moving along the membrane: this makes it faster.

CLICK HERE.

Synapses…? The nervous system communicates with the whole body with the help of neurons. Neurons send

information to other neurons – without even touching each other! HOW? SYNAPSES. A synapse is a gap that separates each neuron from another neuron. An axon terminal is

the end of a neuron; the synapse is in between the axon terminal of one neuron and the dendrites of a different neuron or cell. Since the two cells do not touch, a neuron must send neurotransmitters across the synapse – (chemicals that send the impulse).

The impulse is then changed from an electrical impulse to a chemical impulse. Synapses are essential so that impulses do not travel backwards.- they only go in one direction.

The nervous system adjusts to the feedback loops it receives. Based on if it is good or bad feedback, the nervous system turns certain actions on and certain actions off to maintain homeostasis.

Ex: if something is bitter, the body will not want to eat that thing again, based on the bad feedback.

To keep the body alive and to survive, the brain forces people to do certain actions. This helps promote and keep homeostasis.

Ex: In the medulla oblongata in the brain, impulses are sent that FORCE you to breathe…because breathing is so important!

Integumentary System

What is it made of? skin and nails, hair and glands, andnerve receptors.

What does it do? Protects the body, regulates temperature, protects pigments from UV rays, and produces vitamin D.

What does this SKIN do?

~the nerve receptors help let the body identify thefeel of things, temperature, pain, and pressure.~without these receptors, people would not realizewhen they are in harm and can hurt their bodyvery badly.~keeps important materials in and harmful thingsout! It is a barrier between the outside world andthe inside of the body.

~regulates body temp ~it can produce vitamin D.~ it can help control the body’s temperature.~insulates body with a layer of fat+loose connectivetissue underneath the surface.~ Sweat can control body temperatures, but also help get rid of unwantedchemicals in the body.

What does skin do

~it’s waterproof and it can heal itself!!~protects pigments from UV rays- Melanin keeps skinfrom burning

The epidermis has melanocytes. (cells that make melanin.) Melanin is pigment in the skin. People’s skin color are different, even though everybody has the same amount of melanocytes. In darker people, the melanocytes just produce MORE melanin.

Melanin absorbs UV radiation to protect the body, but too much is not good!

~to protect the body from harmful things, the skincreates oils. It makes the skin soft--However, toomuch can result in acne!

Layers

Skin is made of 2 main layers. Epidermis + dermis. Epidermis=outer layer, thin, mostly dead cells The epidermis reproduces/divides rapidly because skin cells fall off constantly Older cells are pushed to the surface when newer ones are formed. The older cells are forced to be flat, and they lose their cell contents and make KERATIN-strong

protein that has many fibers and is part of the basic structure of hair and nails. Keratincytes-cells that make keratin- they die, and when they do, they become a waterproof

covering for the skin. This is how skin is waterproof and protects the body. Keratin also makes the skin flexible and tough so it doesn’t break easily.

DERMIS= thick layer of skin. Living cells. under the Epidermis. The dermis has blood vessels, nerve endings, glands, sense organs, smooth muscles, and hair

follicles.

Dermis

Helps monitor body temperatures. When it is cold, the dermis’ blood vessels narrow. This way, it helps the body keep its heat, and

there is less heat loss. When it is hot, the vessels grow larger. This makes the body warm and heat is released so the

body will lose heat.

The layer of loose connective tissues is in the hypodermis, which is under the dermis. This layer helps conserve the body’s heat.

The dermis has 2 main types of glands. Sweat and sebaceous (oil) glands They release their contents through tiny holes in the epidermis. Sweat glands produce + release sweat (99% water, 1% salts and fats) to cool the body because

the evaporation takes heat away. Sebaceous glands make sebum (an oily secretion made of fats, waxes, & hydrocarbons). Sebum

keeps the epidermis flexible & waterproof. Sebaceous glands also secrete oils to keep the condition of the hair moist.

Hair

HAIR – made of dead cells that are filled with keratin Made by cells called hair follicles (epidermal cells that reach into the dermis) Protects the head from the sun’s harmful light Hair in the nose, ears, and around eyes keeps particles from entering. It traps them. Eyebrows & eyelashes keep sweat from getting into eyes. Hair helps insulate the body from coldness.

Nails

Nails grow from the nail root. The nail root is an area of cells growing very fast. When the cells divide, the nail root cells fill up on keratin and make strong nails that help protect fingers + toes.

They also help mammals get a good grasp on items and help them to be able to scratch.

Respiratory System

What is it made of? Nose, pharynx, larynx, trachea, bronchi, branchioles, lungs

What does it do? Brings in oxygen for the body and gets rid of carbon dioxide waste.

Standards? a. Students know how the complementary activity of major body systems provides cells with

oxygen and nutrients and removes toxic waste products such as carbon dioxide.

Starting at the mouth…

Air goes in through the pharynx – a tube in the back of the mouth. It then moves to the trachea – the wind pipe. On top of the trachea is the larynx – which contains the vocal cords. From the layrnx, the air

journeys through the trachea to 2 bronchi. These are large passageways in the chest cavity, each leading to a lung. In the lung, the bronchi extend to become smaller bronchi called bronchioles; then the bronchioles divide into alveoli – tiny air sacs in clusters, surrounded by capillaries.

^THIS IS WHERE GAS EXCHANGE OCCURS!!

Gas Exchange In the Alveoli…

OXYGEN dissolves because of the moisture in the inner part of the alveoli. The oxygen then diffuses across the capillary walls into the bloodstream.

Carbon dioxide, on the other hand, diffuses in the opposite direction, from the blood to the alveoli. So then the air is exhaled….getting rid of the CO2!

Inhaling

When you breathe, air pressure, not muscle, is what moves the air into the lungs. However, muscle is needed to inflate lungs.

Lungs are in 2 sacs in the chest cavity. There is a muscle under the chest cavity that expands the chest cavity volume when

the person is inhaling. This produces a partial vacuum in the chest cavity! This only will happen if the cavity is sealed, because a puncture to the chest can cause air to leak, and breathing would not work!

Exhaling

As the diaphragm relaxes, the person exhales. This is because the pressure in the cavity is GREATER than the outside atmospheric pressure. Air must come back out from the lungs.

However, even though exhaling is usually passive, if you voluntarily exhale, more muscle and force is required. Therefore, there are muscles around the chest cavity that contract as the diaphragm relaxes. These muscles help make enough force to blow air out.

Video---CLICK HERE.

Animation

Circulatory System

What is it made of? Heart, blood vessels, blood

Function? To circulate blood through everywhere in the body. To get rid of wastes (Co2) and supply oxygen to all organs and tissues.

Standards? a. Students know how the complementary activity of major body systems

provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide.

Heart.

Structure of the heart muscle: Septum/wall – separates the LEFT section from the RIGHT Upper chamber: receives blood from the body (atrium) Lower chamber: pumps blood out to the body (ventricle) There are 4 chambers. Two of each kind. (A right and left for

each)

Types of circulation

There is two types of circulation. Pulmonary circulation: on the right side of the heart. Pumps oxygen – deprived blood from the

HEART to LUNGS.

At the lungs, carbon dioxide leaves the blood and oxygen is now in the blood. The oxygen-full blood then goes into the heart’s left side, and is pumped to the rest of the body.

Systemic circulation: left side of the heart. Pumps oxygen-RICH blood that came from the lungs to the HEART and to the WHOLE BODY.

When the cells take oxygen from the blood, the blood now is poor in oxygen. The blood then goes back to the right side of the heart and is pumped to the lungs.

Valves in the heart (flaps of connective tissue) are very useful in this system. They keep the oxygen-rich and oxygen-poor blood from mixing. Furthermore, they prevent blood flowing out the heart from flowing back in. Valves in veins also keep blood from flowing the wrong way.

Animation

(Animation from here)

How does the heart beat?

Both the atria and the ventricles have a network of muscle fibers. Whenever one fiber is stimulated, the whole network is.

A group of cardiac muscle cells (sinoatrial node in the right atrium) gives the signal to contract. The Atrium contracts.

Then the signal is picked up by a network of fibers in the atria called atrioventricular node. The signal is then transferred to a network of fibers in the ventricles..which causes the ventricles to contract.

Here’s the pattern: Network in atria contracts-> blood goes out ventricles From ventricles-> blood moves out of the heart and through the body.

Animation

Blood vesselsBlood vessels

Blood vessels are how the blood gets around the body.

3 types: ARTERIES, VEINS, CAPILLARIES.

Arteries: are big vessels. They carry oxygen rich blood TO the body (except for pulmonary arteries). Thick walls withstand pressure that the heart creates when it pushes blood into these arteries. Elasticity helps it withstand pressure.

Capillaries

Capillaries: smallest blood vessels. Only 1 cell wide…so blood cells must line up in single file before going through the capillaries. These vessels are important because they are the site where oxygen and carbon dioxide are exchanged from the alveoli to blood cells, and vice versa.

Veins

Veins: bring back oxygen to the heart. Many veins are located near skeletal muscles, because the movement of blood in veins is against gravity. Muscles contracting help move the blood. Also, that is why in large veins, there are valves to prevent blood from flowing back down.

Example of a vein and a valve that controls the blood flow->

Digestive System

Function: to break down food into pieces so that the body’s cells can use it more easier to make it into energy.

Composed of: mouth, pharynx, esophagus, stomach, small and large intestines, salivary glands, pancreas, liver.

Standards f.Students know the individual functions and sites of secretion of digestive enzymes (amylases,

proteases, nucleases, lipases), stomach acid, and bile salts. g.Students know the homeostatic role of the kidneys in the removal of nitrogenous wastes and

the role of the liver in blood detoxification and glucose balance.

Traveling through the digestive system…. First, we start at the mouth. The mouth mechanically breaks food into smaller pieces with strong

teeth. In the mouth, salivary glands release saliva, which makes food easier to eat. It also begins

digesting food. Saliva has an enzyme – amylase- which breaks down starches and breaks chemical bonds between sugar and starches.

The Esophagus

The food next goes down the esophagus.. Into the stomach. The esophagus is a tube that transports food – it’s smooth muscles push the food down.

A cardiac sphincter prevents food from coming back up the esophagus, but overeating can make it open.

In the stomach…

The contractions from its smooth muscles help mix the food. The stomach lining has gastriac glands that release secretions..

Mucus: protects stomach wall Hydrochloric acid: makes stomach contents acidic Pepsin: enzyme that digests protein

Stomach acids & fluids mixed together….= CHYME~

After the stomach, the chyme goes into the duodenum, the 1st part of the small intestine. Here, most of the chemical digestionoccurs.

The chyme is mixed with enzymes and secretions from the pancreas, liver, and drodenum lining.

The chyme is still being digested .. . . . .

Extra Info..

Pancreas: below the stomach. It is a gland that makes hormones to control blood sugar levels. It makes enzymes that break down carbohydrates, proteins, lipids, and nucleic

acids. (proteases, nucleases, lipases) Kidneys: homeostatic role: removes waste as urine Liver: above the stomach.

Makes bile fluid with lipids and salts in it to dissolve fats, store glucose, and break down toxic substances. The bile fluid is stored in an organ called the gall gladder.

Intestines

Small Intestines The chyme, now, is mostly digested! The small intestine absorbs the nutrients from the chyme. The surface of the intestine is

covered in villi and microvilli. Each villus is a network of blood capillaries and vessels that absorb and transport nutrients. The small intestine uses its smooth muscles to contract and move the chyme.

Last stop – large intestines!

Large Intestines

it is the large intestine’s job to remove water from what is left of the cells. After water is moved across the large intestine wall, what is left is waste. The waste materials pass the rectum and into the toilet.

Skeletal SystemFUNCTIONS! It supports the body to stand up and supports soft tissues. It’s the

framework of the body. Gives muscles something to attach to, so it helps movement. Bones are the things that move when muscles contract. Bones can act as levers.

-to protect internal organs from damage. -bones store and release chemicals and helps maintain the amount of

chemicals.

Made of: BONES AND CARTILAGE, TENDONS, AND LIGAMENTS

Bones. Bones are active tissues. They are made of special cells (found only in bones) and protein fibers.

Calcium salts surround those cells.

Periosteum is a connective tissue that covers the bone. In this cover, there are blood vessels that transport oxygen and nutrients to bone.

Compact bone is right under of the periosteum. But it is not SOLID. It is made of tubes of Mineral Crystals and Protein Fibers.

Spongy bone is inside the outer layer of the compact bone. Spongy bone is arranged at points of stress so that they can support a lot of force. They are NOT

really ‘spongy’. But-they are strong and not as heavy as the dense compact bone.

Why are bones not solid? They’d be way too heavy! Then It would be too hard to move.

Bone Marrow

In bones, there is bone marrow. Bone marrow is soft tissue found in bone cavities and there are 2 types. These two are important in the body.

-red bone marrow produces red blood cells. white blood cells, and platelets made in the spongy bone.

-bones are where blood cells are made! Blood cells – made in soft marrow tissue inside the bones.

-when bones grow old the red bone marrow turns yellow, and the yellow marrow is important because it stores chemical energy. Stores fat. Yellow marrow can also change into red marrow if there is a lot of blood loss in the body. Now it can make blood cells.

-bones have storages of minerals, mainly calcium salts, that are significant to processes of the body.

Special Bone Cells

OSTEOCLASTS-from the bone marrow; formed from 2 cells joining together. DISSOLVE BONE when bone is broken, damaged, etc so new healthy bone can be formed.

OSTEOBLASTS- from bone marrow; create NEW bone. These cells work with each other in teams to make new bone. These cells release mineral deposits that forms bone tissue. This bone tissue replaces cartilage. The osteoblasts turn into osteocytes when they are surrounded by bone tissue – this is how they know their job is successful and complete.

OSTEOCYTES- inside the bone; these cells are in charge of the growth and changing the shape of bones. They maintain the actions of the other cells. Osteocytes know when there is damage or cracks in the bone. Then, these cells tell the osteoclasts where to dissolve the bone.

^those cells take part in ossification- when cartilage is replaced by bone. This happens in all humans, when they are babies.

What’s cartilage? Tendons? Ligaments? Cartilage: made of collagen fibers and elastin. Cartilage absorbs shock, helps places

of the body become flexible (EX: NOSE & EARS), Cartilage is found on the ends of jointed bones, creates an elastic surface for joints so they can move smoothly.

*CARTILAGE IS ALSO IN BABIES. When they’re just born. When they grow, bone replaces the cartilage. HOWEVER------cartilage has no blood vessels, so it needs diffusion to transport Nutrients from (CAPILLARIES) into it.

Tendons: attach muscle to bone. Tendons also send energy and force from them muscles to the bone.

Ligaments connect bone to bone so they stay together.

Joints JOINTS: are places where one bone attaches to another. Joints help MOVEMENT happen

without hurting the bone. Joints keep bones apart so they don’t hit, and they also hold bones in place.

Three types of joints:

Slightly moveable-lets movement happen, but has limits. Bones are separated. Immovable joints-bones are fused together or connected by connective tissue. EX: SKULL! The bones must be joined together to provide full protecting for the brain

Freely movable-these joints let movement go in 1+ directions. Ex: ball & socket, pivot, saddle, hinge.

Excretory System Function: maintains homeostasis. Gets rid of wastes (salts, CO2,

urea)

Made of: skin, lungs, kidney, bladder, urethra.

Standards a. Students know how the complementary activity of major body

systems provides cells with oxygen and nutrients and removes toxic waste products such as carbon dioxide.

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

Kidney

Kidneys are the main organs of this system. It filters blood with wastes in it; the kidney takes out the wastes, excess water, and urea as it passes through the kidney’s artery. Then the clean blood returns to the bloodstream to circulate the body.

A nephron is a unit in a kidney that does work. Each is independent and has its own blood supply. Blood enters through an arteriole. When it goes through the capillaries, the blood is filtered. Waste products are collected in a collecting duct. The waste is then led to the ureter. The cleaned blood leaves the nephron through the venule.

Blood filtration in the kidneys Filtration: Occurs in glomerulus (network of capillaries by a structure called

Bowman’s capsule). Pressure in the blood makes water, salt, glucose, amino acids, and urea to go to the Bowman’s capsule; however, since proteins, plasma, and platelets are too large to pass the permeable membrane, they stay in the blood. The materials that are filtered into the capsule are called “FILTRATES”

Reabsorption: Most of the filtrate goes back into the blood by reabsorption. Not all of it is excreted. Nutrients and water are removed from the filtrate and are reabsorbed by capillaries, back into the blood. What is left behind is urine.

Secretion: as water and nutrients are reabsorbed into the bloodstream, secreted materials are being put into the filtrate from the capillaries. Hydrogen ions are transferred from the blood into the filtrate.

After reabsorption

After reabsorption, urine, which is made of excess salts and water, is emptied into the collecting duct (then later out the body).

Result: filtered blood reenters the bloodstream. Urine is released through urethra.

Kidneys are important in homeostasis Kidneys are important in controlling homeostasis. Kidneys can monitor things in the blood. Activity is controlled mostly by what is in the blood. The kidney can realize if there is

an increase in water in the blood. It can make water reabsorption decrease. The kidney then makes less water go back into the blood (because there is already and increase) & more excess water is disposed of.

Reproductive

Function: to make children To make sex cells – gametes

In females… function: to nurture the baby and protect it when it is developing.

Organs: testes, epididymis, vas deferens, urethra, penis - male

Ovaries, Fallopian tubes, uterus, vagina - female

Creation of Children

This system is essential to create children. It is NOT essential for a human to survive, but it IS essential for

the species to live on. This system creates gametes -> sex cells. Gametes are special

from other cells of the body because it has half the # of chromosomes.

When an ovum and a sperm combine, it fertilizes and eventually becomes a new human being!!

This system can only create active reproductive cells – gametes - once the person reaches puberty…and that is when their reproductive organs are fully developed and functioning.

Puberty

FOR BOTH THE MALE & FEMALE! :

Puberty starts when pituary glands are signaled to create higher amounts of hormones. The hormones FSH and LH change the person’s appearance, and also change their reproductive organs to be more mature and developed.

Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)

Male

LH makes cells in the seminiferous tubules to release testosterone. FSH helps sperm mature

When hormones from puberty are released, the male’s body creates testosterone -> male sex hormone. Testosterone makes males grow more body hair, grow in size, and have a deeper voice.

TESTES = male gonads. Gonads are sex organs.

The new hormones, including testosterone, also make the body create sperm. Sperm is the male reproductive gamete (sex cell) and are created in seminiferous tubules, which are small tubules in the testes. The testes are in a scrotum. The scrotum is a sac, part of the reproductive organs, which contains the testes. The scrotum moves up towards the body for heat when it is cold, or when it is hot, the sac moves down. The scrotum is in charge of keeping a proper temperature for the sperm to be created. Sperm is produced in the process of meiosis.

Journey of the Sperm

The sperm then travels to the epididymis, where the sperm is stored and matures. Then, the sperm moves through the vas deferens (tube) that later joins together with another tube called the urethra. As the sperm travels to the end of the penis, seminal vesicles, the prostate gland, and the bulbourethral gland release seminal fluid. The seminal fluid combines with the sperm – creating semen. Through the urethra, the semen then is ejaculated out of the body through the penis.

Semen is released by the automatic nervous system of the man’s body when he is sexually excited. It happens automatically, usually not voluntarily, when a male and female are in the act of reproducing.

Female

Female:: the released FSH makes cells in the ovaries of the woman to make estrogen….female sex hormone. The female develops physical characteristics – wider hips, growth in breasts.

Only one egg – ovum (female gamete) is made each month.

Female gonad: OVARY

There are two ovaries, and in each ovary, there are around 400,000 primary follicles (premature eggs) – unlike men, women do not make new eggs. They are born with what they have. A follicle is a developing egg surrounded by follicle cells. Follicle cells help an egg mature. Eggs mature in their follicles.

Female pt 2 Caused by the hormone FSH, about every month, a follicle grows bigger and the egg

goes through meiosis.

Then, a large egg (containing ½ the number of regular chromosomes – HAPLOID) and 3 smaller cells – polar bodies- will be created… however, the polar bodies are not important and will become cell waste.

Now, the follicle has matured and breaks open, letting the egg travel from the ovaries one of the 2 Fallopian tubes. This is ovulation. Tiny hairs in the tube help move the egg into the uterus.

The uterus’ thick and muscular lining is prepared to receive and nurture a fertilized egg until it grows into a baby – but if fertilization did not occur, the egg and the lining are disposed of through the vagina.

This menstrual cycle (when an egg develops, is released, goes to the uterus, and goes out of the vagina), is also called a period.

Endocrine System

Made of the following glands: pituitary gland, parathyroid gland, pineal gland, the hypothalamus, thyroid, adrenal, pancreas and the ovaries/testes.

Function: controls growth, metabolism, and reproduction. This system watches over the processes and growth of the human over time.

Standards? a. Students know how the complementary activity of major body systems provides cells with

oxygen and nutrients and removes toxic waste products such as carbon dioxide. c. Students know how feedback loops in the nervous and endocrine systems regulate conditions

in the body. i.Students know how hormones (including digestive, reproductive, osmoregulatory) provide

internal feedback mechanisms for homeostasis at the cellular level and in whole organisms.

Glands

2 types of glands. EXOCRINE: release products through

tubes, ex: sweat and tears. ENDOCRINE: release products into

bloodstream. (endocrine glands secrete hormones).

Hormones

Hormones affect our whole body. They are chemicals that transmit information to only certain cells that are meant to receive the message. Hormones cause changes in people’s bodies when they are growing in age. They travel to a specific place…called target cells. The shape of the hormone must match the shape of the target cell so they can fit together.

Once the receptor protein/target cell is activated by the protein, its activities change (because its shape changed!) It’s like an on/off switch activated by the hormone.

Picture of hormones going to their target cells->

Hormones

2 types of hormones: steroid – these hormones can cross cell membranes of target cells easily. They attach to a DNA control sequence and can directly turn on or turn off certain genes of the cell.

Nonsteroid hormones: usually cannot pass through cell membranes, so it is harder for them to reach their target cells. The hormone attaches to receptors on the cell membrane, activating an enzyme that then activates more messengers that carry the message to the inside of the cell.

Glands’ functions Some functions for the glands of the system: Hypothalamus: makes hormones that control pituitary gland. Pituitary gland: makes hormones that regulate other endocrine glands. Parathyroid glands: secrete a parathyroid hormone –controls amount of calcium in blood. Thymus: releases thymosin during a person’s childhood to activate the creation of more T cells. Adrenal glands: release hormones that help the body handle stress. Thyroid: makes thyroxine – monitors metabolism Pancreas: makes insulin and glucagon – monitors amount of glucose in blood.

Reproductive gonads (sex organs) – -Female: ovaries make progesterone and estrogen.

Estrogen gives the woman more female characteristics (wider hips and development of breasts) and also help the eggsdevelop. Progesterone helps make the uterus ready for a fertilizedegg.

- Male: Testis: make testosterone, which make the male gain more size, hair, and have a deeper voice.

Homeostasis The Endocrine System is important in keeping homeostasis stable because it affects

the affects cells’, tissues’ and organs’ activities everywhere in the body. Hormones give feedback to the endocrine system to keep the body at a well-monitored state.

There is negative and positive feedback. Most hormone systems use negative feedback to control the amount of hormone

released. In negative feedback, substances are released to stop the release of a certain hormone.

In positive feedback, substances are release to activate the release of a certain hormone.

This is how the body knows when to release hormones and when to stop. Thus, the body also maintains homeostasis.

EX: puberty. The endocrine system gets a signal for when to start releasing hormones. Another example: release of sweat when the body is hot. = maintaining homeostasis.

Muscular System

Purpose: to let the body be able to move, to help move food through the digestive system, and to regulate blood pressure.

Made of 3 types of muscles: skeletal, smooth, cardiac Standards:

h.Students know the cellular and molecular basis of muscle contraction, including the roles of actin, myosin,

Ca+2, and ATP.

What the different types of muscles do.Smooth muscles are usually not voluntarily controlled. Smooth muscles are in the

stomach, blood vessels, and intestines and they move food through the digestive system. They are connected to one another by gap junctions – this lets electric impulses be transferred from one muscle to another one.

Cardiac muscles

Cardiac muscles are only in the heart. They are not under complete voluntary control of the central nervous system. We do not have to think about using these muscles. Cardiac muscles are connected to each other also by gap junctions

Skeletal Muscles

Skeletal muscles are made from alternating thicknesses of filaments. Thick =contains myosin (a protein). Thin = made of mainly actin

THESE TWO PROTEINS MAKE MUSCLES CONTRACT! The muscles contract when thin filaments slide over thick ones.

How muscles contract:: In muscle contraction, myosin filaments attach to a binding site on an

actin. This is called a cross bridge. With the help of ATP, the myosin crossbridge changes shape. It then

pulls the actin toward the center, and the crossbridge is broken. Then myosin bonds to another actin, and the cycle starts again.

Skeletal muscle contractions are controlled by impulses from motor neurons. The impulses tell the muscles what to do.

Muscle contraction needs ATP energy!Muscle contraction needs ATP energy!

Calcium ions control regulatory proteins – those regulatory proteins allow actin and myosin to interact with one another.

Immune System

Made of: white blood cells, t cells, b cells. Function: to protect the body from and to get rid of harmful bacteria and viruses. Standards: 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 infections, 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.

Defense.

Non specific defenses block everything out First line of defense: keeps pathogens out

Skin – prevents things from entering the body Mucus, sweat, saliva, and tears can keep them from

entering

Hairs can keep dust from entering the body

Skin->

2nd line of defense

2nd line of defense: inflammatory responseinflammatory response: a reaction to pathogens entering the body and a response to tissue damage. In this response, phagocytes (cells that engulf other cells to destroy them) track and try to kill the pathogens.

White blood cells fight invaders.

The immune system can also make the temperature of the body rise to kill pathogens and slow them down from spreading .. This is a fever.

Specific Defenses

When a pathogen makes it across the nonspecific defenses, it now faces specific ones. (this is called an immune response).

ANTIGENS trigger the response. lymphocytes (type of white blood cell) make ANTIBODIES to fight

the pathogens. Antibodies track certain antigens down. The antibodies attach to the pathogen with a certain, specific antigen.

There are antigen bonding sites on the antibody, where they attach. Antibodies help destroy antigens by clumping the antigens into a big group.

This big clump will draw in phagocytes – and the phagocytes will “eat” and get rid of the whole clump of antibodies and antigens.

How are SPECIFIC antibodies made?

There are millions of B cells (AKA B lymphocytes – type of white blood cell) in our body. When they develop, each cell’s genes slightly change. Therefore, each cell can make a different antibody .. But the differences are small.

When a pathogen gets into the body, the antigens on the pathogen are detected by SOME of the B cells – only some, because all of them are slightly not the same. When this certain group of B cells senses a specific antigen, it produces very quickly and releases plasma cells.

Plasma cells are specialized B cells. Plasma cells release antibodies to clump the pathogens and get rid of them.

T cells (T lymphocytes – another white blood cell) help activate plasma cells.

Why do people stay immune to a pathogen if they have already had it? People stay immune to previously experienced pathogens because… their T cells and B cells

remember how to fight against it. Because of this, the T cells and B cells can quickly get rid of the pathogens when it is detected.

Vaccines

Active Immunity is when the body receives a WEAKER form of a pathogen and becomes immune to it. B cells can detect certain antigens, and when it does, it creates many plasma cells that release antibodies to destroy the pathogen. When a weaker form of a pathogen is entered into the body (a vaccine) the B cells can make antibodies against it to protect the body without having the body being harmed!

HIV/AIDS

When a person’s immune system is compromised, the body can no longer fight the disease as well. Therefore, the person may die from a disease that their white blood cells cannot fight off.

What’s the Difference?

What’s the difference between bacteria and viruses?

BACTERIA: living things. They can be killed by antibiotics and medicines.

VIRUSES: are not living. To get rid of them, rest and help your immune system do the job for you.

Sources

Sources used: http://www.sirinet.net http://www.besthealth.com/ http://www.drstandley.com/ http://www.ivy-rose.co.uk/ http://depts.washington.edu/ http://www.emc.maricopa.edu/ http://www.kidshealth.org http://faculty.washington.edu http://www.estrellamountain.edu/ http://www.thinkmuscle.com Prentice Hall Biology Book Mr. Thiel (on the previous slide)