human body systems- skeletal, muscular, integumentary, nervous

7/30/2019 Human Body Systems- Skeletal, Muscular, Integumentary, Nervous

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Conceptual Learning Objectives for Human Body Systems Unit 1

Skeletal, Muscle, Integumentary, & Nervous Systems

Themes of unit:

Recognize that the bodys systems interact to maintain homeostasis. Be able to

distinguish different forms of homeostatic imbalance and how disruption of

specific anatomical structure leads to the loss of specific physiological functions.

Homeostasis is the normal functioning of the human body, or of any of its systems or organs.

Homeostatic imbalance can occur due to illness, or due to physical ailments such as a broken

bone or a cut or bruise. Anatomy is the structure of an organism and its parts, physiology is the

study of what the parts do, and how they do it. This is why disruption of anatomical structure can

lead to disruption of physiological functions.

Explain how the muscular/skeletal system (skeletal, smooth and cardiac muscles,

bones, cartilage, ligaments, tendons) works with other systems to support the

body and allow for movement. Recognize that bones produce blood cells.

The skeleton is the sturdy frame of the body, and muscles are the organs which move the

skeleton through joints, tendons, and ligaments. Joints connect different bones and allow

movement with the help of muscles (pivot, ball and socket, gliding, hinge joints). Ligaments are a

connective tissue that hold bones into the movable joints. Tendons are another type of

connective tissue that connect muscles to bones. An exception is the eye ligament.

Name and describe the 6 main functions of the skeletal system.

The skeleton provides a strong frame for the body. It houses and protects the soft organs of the

body, such as the heart, lungs, and brain. The skeleton also aids in movement, giving muscles a

place to attach to. The skeleton helps maintain mineral homeostasis, releasing calcium and

phosphorus into the blood when needed. The skeleton produces new red blood cells through red

bone marrow. Yellow bone marrow serves as storage for fats and lipids. So, the six main

functions are support, protection, movement, mineral homeostasis, blood cell production, and

storage. Babies are mostly made of cartilage though.


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Describe the anatomy of a typical long bone (such as a femur).

Bone is a solid network of living cells and fibers that are supported by bone matrix. Bone matrix

is made of the hard mineral made of calcium phosphate and flexible fibers of the protein

collagen. A sheet of fibrous connective tissue surrounds the bone and helps it heal from a

fracture. Cartilage cushions the joints. The shaft of the bone has a central cavity filled with yellow

bone marrow. Yellow bone marrow stores fat. Spongy bone is located at the ends of the bone

and contains red bone marrow, which produces new blood cells.

Distinguish the different types of bone cells and their specific functions.

There are four types of bone cells. First, Osteocytes. These cells maintain the mineral and

protein content of the bone is in the inside and compact bone on the outside. The longer part is

the Periosteum and bone marrow lies on the inside surrounding bone, they cannot divide, and

participate in the repair of damaged bone. Osteoblasts produce more Osteocytes in a process

called Osteogenesis. Osteoprogenitor cells are stem cells that divide into Osteoblasts. They

maintain the number of Osteoblasts and aid in the repair of damaged bone. Osteoclasts remove

and recycle bone matter. they do this by secreting acids and enzymes to dissolve the bone in

order for new bone matter to be produced. This Process is called Osteolysis. So to recap, the

four cells are Osteocytes, Osteoblasts, Osteoprogenitors, and Osteoclasts.

Explain how skeletons are held together and how bones connect to muscles.

Bones are held together with joints. some joints allow for no movement such as the joints of the

ribs and spine, or the bones in the skull. other joints allow for some range of motion, such as the

joint in the knee, or the joint in the shoulder or pelvis. In these joints the bones are held together

by a fibrous connective tissue called a ligament. Bones have bumps on them, where a different

connective tissue called a tendon attaches the bone to the muscle.

Distinguish between the three types of muscle.

The three types of muscle are skeletal, smooth, and cardiac. Skeletal muscles are

attached to the skeleton, and for the mostpart, are under conscious control (voluntary muscles). Smooth muscle surrounds soft organs

such as the stomach, and the intestines. Cardiac muscle is the muscle that pumps the heart.

Smooth and cardiac muscles do not require conscious control to function (involuntary muscles).

Skeletal muscle cells are long and cylinder shaped, with striations due to the sarcomeres.

Smooth muscles have spindle shaped cells, being tapered at the end. Cardiac muscle cells


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make branching connections with each other.

Explain what happens when a muscle contracts.

In a muscle, the functional unit is the sarcomere. The sarcomere is composed of two types of

filaments, thin and thick. the thin filament is composed of the protein actin, while the thick

filaments are composed of the protein myosin. First the myosin heads bind to the thin filaments,

then the myosin heads bend, pulling the thin filaments towards the center of the sarcomere. ATP

then binds to each myosin head, releasing it from the thin filament. the myosin head can now

attach to a new spot further down the thin filament and pull it farther along. creating a contraction.

Distinguish between abduction and adduction.

Abduction is muscle movement away from the body and adduction is movement towards the

body. For example, lifting your arm is adduction, and putting it down is abduction.

Explain how the skin is constructed of multiple layers of tissue and functions as a

barrier between the bodys internal and external environment.

Skin is constructed in three layers. From outside to inside: the epidermis, the dermis, and the

hypodermis. It functions as a barrier between the internal and external environment by acting as

a barrier to infections, a regulator of body temperature, a remover of waste products (sweat),

and a protector against UV radiation.

describe the 4 major functions of the Integumentary system.

The integumentary system is your bodys outer covering that physically separates the body fromthe external environment. It helps regulate body temperature through sweating and insulating, it

protects from UV radiation (hair), it also acts as a barrier to infection (physical barrier of skin),

and it is a remover of waste product.

Distinguish between the 3 different layers of skin.

Epidermis- Outermost layer, mostly dead cells that flake off as new cells replace them

Dermis- Middle layer, contains hair follicles, oil and sweat glands, muscles, nerves, and blood

vessels.

Hypodermis- innermost layer, fat storing cells and blood vessels.

Explain how the body regulates temperature.

In order to regulate temperature the body, when hot, the body dilates the blood vessels and the

blood temperature decreases, the blood signals the brain, which signals the skin via nerves to


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open up pores in order to release sweat. When air blows over the sweat, it leaves a cooling

sensation. When cold, blood temperature increases, blood vessels constrict and this signals the

skin to close the pores which are letting out sweat. Also the muscles start contracting rapidly

(shivering) in order to generate heat.

Explain how the nervous system (brain, spinal cord, sensory neurons, motor

neurons) mediates communication among different parts of the body and

mediates the bodys interactions with the environment. Identify the basic unit of

the nervous system, the neuron, and explain generally how it works.

This answer may or may not be complete BS...well that doesnt make me confident... Nerve

cells are located in the dermis of the skin, as well as in various other tissue types. Receptors

sensing heat (thermoreceptors), chemicals (chemoreceptors), touch (mechanoreceptors), light

(photoreceptors), pain (pain receptors) receive environmental signals, and transmit these

signals to the brain through a series of action potentials. The brain, in turn, will send signals to

the motor division of the body part that sent the signal to perform some action to respond to the

stimulus. The brains response to this stimulus depends on the frequency of the stimulus (higher

frequency = more powerful stimulus). In this way, the nervous system is able to communicate

signals throughout the body.

The neurons basic parts are the cell body (with a nucleus), dendrites, and an axon. Dendrites

receive impulses from other neurons and carry them to the cell body. Axons carry impulses from

the cell body to other neurons. Axons are surrounded by many myelin sheaths with spaces in

between called nodes. Action potentials cannot travel across myelin sheaths, so they jump

between nodes. This speeds the transmission of signals because the action potential doesnt

have to move across a great deal more axon to get where it needs to go.

Explain, in general terms, the functions of the major parts of the brain.

Cerebrum - is the most complex it regulates memory, and long term storage of information it is

also the brains main processor. It is divided into two hemispheres: the left controls the right side

of the body, and vice versa. Left side controls logical thinking, right side controls creativethinking.

Hypothalamus - controls body temperature, thirst, hunger, water balance, and emotions.

Brain Stem (pons/medulla oblongata) - this part regulates body processes that are involuntary

and are not consciously controlled, like the heart beating. (smooth and cardiac muscle)

Cerebellum - controls all voluntary body movement (skeletal muscle)


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Thalamus - sorts all information coming into the brain

Diagram the main sensory and motor pathways involved in a reflex arc.

Identify the parts of a neuron and show the direction in which a nerveimpulse passes.

The first part of a neuron is the cell body and the nucleus. Branching from the cell body are the

dendrites which carry signals toward the cell body. Axons then carry these signals (action

potentials) away from the cell body. The axons are insulated by myelin sheaths, which allows the

signal to hop from node to node speeding the transmission process and carrying the signal to

the next neuron faster (we didnt learn this, but the myelin sheaths cover things called Schwann

cells, or neurolemmocytes). The cell body is nucleated.

Explain the transmission of nerve impulses along a neuron.

There are more positive ions outside the cell than inside, creating potential energy. When the cell

is hit by a stimulus, the membrane of the cell becomes more permeable and more NA+ ions

diffuse into the cell, causing depolarization and then more NA+ ions are let into the cell by

channel gates, which causes action potential. This is a big chain reaction which moves across

the axon towards other cells. K+ are potassium ions while NA+ are sodium ions.

Describe how nerve impulses cross a synapse.

1. action potential causes vesicles to release chemical signals called neurotransmitters.

2. neurotransmitters cross through the tiny space called the synaptic cleft

3. receptor molecules on the receiving neuron accept the neurotransmitter and may create a

new action potential, but the synapse has been crossed.

Explain how the human eye works.

Light enters the eye through the cornea, next through the aqueous humor, then through the pupil


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which is a hole. The pupil gets larger and smaller based on the availability of light. It is

surrounded by the Iris which is the colored part of an eye. The light next hits your lens, which

directs and bends the light to your retina which receives the signal and delivers it to the optic

nerve. The optic nerve then sends it to the brain. When light is closer the lens is more bent and

when its farther away the lens flattens out. Cones in the eye respond to blue, red and green.

Rods are more sensitive and help you see in the dark, however can not distinguish between

colors.

Explain how the human ear works.

Sound, which consists of sound waves, makes its way to the ear, the sound comes in through

the ear canal travels down to the eardrum, which makes the eardrum vibrate. This vibration

passes through the ossicles (ear bones) and into the cochlea. In the cochlea, the vibrations pass

through the fluid and that makes the hair cells move. The hair movement in the cochlea makes

an electric signal pass through the auditory nerve and to the brain. The semicircular canals aid in

balance because the are located in the X, Y and Z planes, so when the head tilts a certain way,

the hair cells detect the movement.

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Integumentary system: covers the body and protects it from injury, infection, excessive heat orcold, and drying out.

Skeletal system: provides body support, protects certain organs such as the brain and lungs,and works w/ the muscular system in body movements.

Muscular system: enables body movement and facial expressions essential to humancommunication.

Nervous system: coordinates bodys activities by detecting stimuli and directing the bodys

responses.

Anatomy: study of an organism's structure.

Physiology: study of functions or processes in an organism.

Tissue: co-operating unit of many similar cells that perform a specific function.


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Organ: unit consisting of several tissues that together perform a specific task.

Organ system: unit of multiple organs that together perform a vital body function.

Epithelial tissue: sheets of closely packed cells that cover the surface of the body and line the

internal organs.

Connective tissue: groups of cells that hold together and support other tissues and cushion,

insulate, and connect organs.

Nervous tissue: tissue that transmits signals in the body in response to changes in the

environment.

Neuron: nerve cell basic unit of nervous tissue.

Skeletal muscle: voluntary muscle attached to the skeleton that allows movement of the body.

They are composed of skeletal muscle tissue.

Cardiac muscle: involuntary muscle that causes the heart to pump blood.

Smooth muscle: involuntary muscle found in most organs of the body.

Homeostasis: internal stability or "steady state" maintained by the body.

Hormone: signal molecule released into the bloodstream that triggers particular responses.

Interstitial fluid: aqueous solution that fills the gaps between cells in a tissue.

Integumentarysystem: outer covering that physically separates the body from the external

environment.

Epidermis: outermost layer of skin.

Melanin: pigmented protein that gives skin its color.

Dermis: layer of skin beneath and supporting the epidermis, made up mostly of fibrous

connective tissue that gives the skin its strength and elasticity.

Hypodermis: tissue layer beneath the dermis contains adipose tissue, a connective tissue that

includes fat-storing cells and blood vessels.

Vertebra: segment of the backbone encloses and protects the nerve cord.

Cartilage: type of connective tissue softer than bone.

Marrow: specialized tissue found in bone yellow bone marrow consists of stored fat that serves

as an energy reserve red bone marrow makes cells that develop into blood cells.

Joint: area where one bone meets another.

Ligament: strong fibrous connective tissue that holds together the bones in movable joints.

Arthritis: group of skeletal disorders characterized by inflamed joints.

Osteoporosis: disorder in which bones become thinner, more porous, and more easily broken.


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Tendon: dense connective tissue that attaches a muscle to a bone.

Musclefiber: single, long cylindrical muscle cell containing many nuclei.

Myofibril: unit of muscle fiber made up of smaller units that contract (sarcomeres).

Sarcomere: unit of contraction in a muscle fiber.

Actin: twisted, thin filament in a muscle fiber.

Myosin: thick filament in a muscle fiber has bump-like projections.

Centralnervoussystem (CNS): the body's primary information processing system includes

the brain and spinal cord.

Peripheral nervous system (PNS): network of nerves carrying signals into and out of the

central nervous system (nerve tissue outside the CNS).

Nerve: bundle or bundles of neuron fibers surrounded by connective tissue.

Stimulus: environmental change that triggers a response.Sensoryneuron: nerve cell that carries information from the environment to the central nervous

system.

Sensoryreceptor: specialized cell that transmits signals to sensory neurons.

Interneuron: nerve cell located entirely in the central nervous system that integrates sensory

information and sends motor commands.

Motorneuron: nerve cell that carries signals from the central nervous system to muscle or

gland cells.

Reflex: rapid, automatic response to a stimulus.

Dendrite: neuron fiber that receives signals and carries them toward the cell body.

Axon: neuron fiber that carries electric impulses away from the cell body and toward other cells.

Myelin sheath: thick coat of material that surrounds and insulates the axon of some neurons.

Node: uninsulated spaces between the "beads" of a myelin sheath where an action potential can

be transmitted.

Resting potential: voltage across the plasma membrane of a resting neuron.

Depolarization: voltage change that occurs when the difference in charge across a membrane

decreases.

Threshold: minimum change in a membrane's voltage that must occur to generate an action

potential.

Actionpotential: change in voltage across the plasma membrane of a neuron resulting in a

nerve signal.


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Synapse: junction between two neurons or a neuron and another cell where electrical or

chemical signals are relayed.

Synapticcleft: tiny space separating a knob of a transmitting neuron from a receiving neuron or

other cell.

Neurotransmitter: chemical messenger that carries information from one neuron to another or

to another cell (small, nitrogen-containing organic compound).

Somaticnervoussystem: subdivision of the motor division of the peripheral nervous system

that controls the voluntary movement of skeletal muscles.

Autonomic nervous system: subdivision of the motor division of the peripheral nervous system

that regulates the internal environment.

Sympathetic division: division of the autonomic nervous system that generally prepares the

body for energy-consuming activities. Basically, if you find yourself in a situation which requires

quick responses and reactions, the sympathetic nervous system lowers digestive functions, etc.

and the liver converts glycogen into glucose for use by the body. The body also begins to

produce more adrenaline to heighten awareness of the surroundings. Fight or Flight

Parasympathetic division: division of the autonomic nervous system that conserves energy.

This is as opposed to the sympathetic NS. The parasympathetic NS calms the body down,

restarts body maintenance functions, and reduces adrenaline levels in the bloodstream.

Cerebrum: largest and most complex part of the brain, made up of the left and right

hemispheres.Corpuscallosum: band of nerve fibers that support communication between the two cerebral

hemispheres.

Cerebralcortex: outer region of cerebrum containing integration centers for higher brain

functions.

Cerebellum: part of the brain located below the cerebrum and above the spinal cord planning

center that coordinates body movement.

Brainstem: lower section of the brain including the medulla oblongata, pons, and midbrain that

filters information going to and from the brain.

Thalamus: brain region that sorts and exerts some control over information going to and from

the cerebral cortex.

Hypothalamus: region of the brain that is the "master control center" of the endocrine system

functions in maintaining homeostasis by regulating temperature, blood pressure, and other


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conditions.

Limbicsystem: system of regions of the brain that interact with the cerebral cortex in emotion

and memory. Involves several different areas that integrate and relay info, including the

amygdala, hippocampus, and parts of the cerebral cortex, hypothalamus, and thalamus.

Sensation: awareness of sensory stimuli.

Perception: meaningful interpretation of sensory data by the central nervous system.

Cornea: transparent area at the front of the eye through which light enters.

Iris: colored part of the eye controls the amount of light that enters the eye by regulating the size

of the pupil.

Pupil: opening in the iris that admits light into the eye.

Retina: inner surface of the eye that is lined with millions of photoreceptor cells.

Cone: photoreceptor cell in the retina that is stimulated in bright light, enabling color vision.

Rod: photoreceptor in the retina that enables vision in dim light.

Auditory canal: part of the outer ear that channels sounds from the outside to the eardrum.

Eardrum: sheet of tissue separating the outer ear from the middle ear that vibrates when

stimulated by sound waves.

Auditory tube: air passage between the middle ear and throat that equalizes air pressure on

either side of the eardrum also called the Eustachian tube.

Cochlea: coiled tube in the inner ear containing hairlike projections that function in hearing.

Tolerance: resistance to a drug's effects such that more of the drug is needed to produce the

same effect.

Addiction: uncontrollable dependence on a drug.

Withdrawal: psychological and/or physical symptoms experienced when a person stops taking

a drug to which he or she is addicted.

Stimulant: drug, such as caffeine, nicotine, and cocaine, which generally increases activity in

the central nervous system.

Depressant: drug such as alcohol or tranquilizers that, in general, slows central nervous

system activity.

Marijuana: drug made from dried pieces of the hemp plant.

Opiate: narcotic, such as morphine or heroin, which is derived from opium poppies.

Hallucinogen: drug that causes a person to see, hear, and perceive things that do not exist.

Ecstasy: synthetic drug that causes stimulant-like and hallucinogenic-like effects in the user.


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Inhalant: substance, such as certain aerosols, whose vapors produce mind-altering effects.

Sources of Homeostatic Imbalance

Trauma Acute injuries, such as a car crash, or repetitive injuries, such

as tendonitis, lead to damaged tissue.

Environmental Influences Solar Radiation or a high sugar diet can

damage tissues or stress body systems

Genetic Variation Some genes, such as sickle cell trait, alter oxygen

capacity, but provide for malaria resistance. Others, like Cystic Fibrosis,

provide no benefit.

Parasites & Viruses Parasites like tapeworms or bacterial infections

consume human tissues for energy. Viruses turn cells into virus

factories. In both cases, tissues are damaged and energy is lost.

Design Compromises & Evolutionary Legacies Humans are bipedal

which allows for using their hands for carrying objects, but predisposes us

to back pain. Unlike most other mammals, humans are not able to

manufacture Vitamin C and therefore must consume it regularly. These

evolutionary vestiges leave humans vulnerable to homeostatic imbalance.

Joints

Ball and Socket Joint (shoulder) - bones can rotate back and forth and side to side

Hinge Joint (knee) - allows movement back and forth in one plane

Pivot Joint (top of neck and base of skull) - one bone rotates around another

Immovable Joint (bones of skull, ribs, pelvis) - bones are fused together and cant move.


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Anatomy of an Ear

Auditory canal - the tube through which sound travels to the eardrum.

Eardrum - a thin membrane that vibrates when sound waves reach it.

Hammer- a tiny bone that passes vibrations from the eardrum to the anvil.

Anvil - a tiny bone that passes vibrations from the hammer to the stirrup.

Stirrup - a tiny, U-shaped bone that passes vibrations from the stirrup to the cochlea. This is the

smallest bone in the human body.

Cochlea - a spiral-shaped, fluid-filled inner ear structure it is lined with cilia (tiny hairs) that

move when vibrated and cause a nerve impulse to form.

Auditory nerves - these carry electro-chemical signals from the inner ear (the cochlea) to the

brain.

Auditory tube - a tube that connects the middle ear to the back of the nose it equalizes the

pressure between the middle ear and the air outside. When you "pop" your ears as you change

altitude (going up a mountain or in an airplane), you are equalizing the air pressure in your middle

ear. Also known as the Eustachian tube

Semicircular canals - three loops of fluid-filled tubes that are attached to the cochlea in the

inner ear. They help us maintain our sense of balance.


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Anatomy of an Eye

Sclera - tough layer of connective tissue forming the outer white covering of the eye.

Cornea - the clear, dome-shaped tissue covering the front of the eye.

Iris - the colored part of the eye - it controls the amount of light that enters the eye by changing

the size of the pupil.

Lens - a crystalline structure located just behind the iris - it focuses light onto the retina.

Optic nerve - the nerve that transmits electrical impulses from the retina to the brain.

Pupil - the opening in the center of the iris- it changes size as the amount of light changes (the

more light, the smaller the hole).

Retina - sensory tissue that lines the back of the eye. It contains millions of photoreceptors that

convert light rays into electrical impulses that are relayed to the brain via the optic nerve.

Rods - Photoreceptors in the retina that sense red, green, and blue light.

Cones - Photoreceptors in the retina that are very sensitive to light, allowing you to see pretty

well in the dark, but only in grayscale.

Ligaments in the eye connect muscle to muscle, unlike other ligaments which connect bones to

bones.

human body systems- skeletal, muscular, integumentary, nervous

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