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Anatomy Chapter 35 BIO Cheat Sheet Cheat Sheet by

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Human Organ Systems

- nervous system: recognizes and coordi­nates the body's response to changes in its internal and external enviro­nments
- integu­mentary system: serves as a barrier against infection and injury; helps to regulate body temper­ature; provides protection against UV from the sun
- respir­atory system: provides oxygen needed for cellular respir­ation and removes excess carbon dioxide from the body
- digestive system: converts foods into simpler molecules that can be used by the cells of the body; absorbs food; eliminates wastes
- excertory system: eliminates waste products from the body in ways that mantain homeos­tasis
- skeletal system: supports the body; protects internal organs; allows movement; stores mineral reserves; provides a site for blood cell formation
- muscular system: works with skeletal system to produce voluntary movement; helps to circulate blood and move food through the digestive system
- circul­atory system: brings oxygen, nutrients, and hormones to cells; fights infection; removes cell wastes; helps to regulate body temper­ature
- endocrine system: controls growth, develo­pment, and metabo­lism; mantains homeos­tasis
- reprod­uctive system: produces reprod­uctive cells; in females, nurtures and protects developing embryo
- lympha­tic­/immune systems: helps protect the body from disease; collects fuid lost from blood vessels and returns the fluid to the circul­atory system

Organi­zation of the Body

- levels of organi­zation in a multic­ellular organism: cells, tissues, organs, and organ systems

- cells: basic unit of function in living things
- specalized cells: uniquely suited to perform a specific function

- tissues: group of cells that perform a single function; ex: connecting a muscle to a bone
- four types of tissue:
1) epithelial tissue: glands and tissues that cover interior and exterior body surfaces
2) connective tissue: provides support for the body and connects its parts
3) nervous tissue: transmits nerve impulses throughout body
4) muscle tissue: enables body to move

- organs: group of different types of tissues that perform a complex function; ex: sight

- organ systems: group of organs that perform closely related functions

Mainta­ining Homeos­tasis

- homeos­tasis: organisms keep internal conditions relatively constant despite changes in external enviro­nments
- maintained by feedback loops

- heating system controlled y feedback inhibition
- feedback inhibi­tion: negative feedback; stimulus produces a response that opposes the original stimulus

- mantaining of homeos­tasis -> integr­ation of all organ systems
- ex: body temp. (below 37°C -> hypoth­almus speeds up activi­ties, abole 37°C -> hypoth­almus slows down activi­ties)


- nervous system: controls and coordi­nates functions throughout the body and responds to internal and external stimuli

Neurons – cells that transmit impulses – bundles of neurons
make up nerves
1. sensory – from enviro­nment to brain
2. motor – from brain to muscles & glands
3. intern­eurons – connect sensory & motor

Parts of a Neuron
1. Cell Body – nucleus here; most metabolic activity
2. Dendrites – small “branches” (carries impulses toward cell body)
3. Axon – a long fiber “tail” (carries impulses away from cell body)
4. Myelin sheath – insulating membrane; creates gaps called nodes

Nerve Impulse

- resting nueron: negative charge inside, positive charge outside (sodium ions out; potassium ions in)
- resting potential: electrical charge throughout cell membrane of a nueron in its resting state
- moving nerve impulse: begins when a neuron is stimulated by another neuron or by its enviro­nment
- action potential: positive inside, negative outside
- threshold: all or nothing; minimum level of stimulus needed to produce an impulse

Central Nervous System

- central nervous system: relays messages, processes inform­ation, and analyzes inform­ation
- meninges: three layers of connective tissue that the brain and spinal cord are wrapped in
- cerebr­ospinal fluid: space btwn meninges and central nervous system that acts as as a shock absorber -> protects central nervous system; allows for exchange of nutrients and waste products btwn blood & tissue

The Synapse

- synapse: location where nueron cantra­nsfer impulse to another cell
- ex: moton nuerons pass impulse -> muscle cells
- synaptic cleft: seperates axon terminal fom dendrites
- use neurot­ran­smi­tters to send impulse

The Brain

- brain: place where impulses originate and flow
- approx 100 billion nuerons & is about 1.4 kilograms

1. The Cerebrum – voluntary activities of the brain
- right and eft hems. connected by corpus callousm
- hems deal with opposite sides of body
- outer layer (cerebral cortex) -> grey matter - desnly packed nerve cell bodies
- inner layer -> white matter - bundles of axons & myelin sheaths
2. The Cerebellum – coordi­nates muscles
- located at back of skull
3. The Brain Stem – controls uncons­cious activity
- connects brain and spinal cord
a. Pons – upper part – sensory control
b. Medulla Oblongata – lower part – uncons­cious
4. The Thalamus and Hypoth­alamus
a. thalmus: recieves messages from sensory recpts. & relays to cerebelum
b. hypoth­almus: control center for recog. & analysis for hunger, thirst, fatigue, anger, body temp.

The Spinal Cord

- reflex: quick, automatic response to a stimulus

The Peripheral Nervous System

somatic nervous system:
autonomic nervous system:
- regulates activities under conscious control
- controls functions not in concious control
- reflex arc
- sympat­hetic and parasy­mpa­thetic nervous system
- transmits impulses from sense organs to central nervous system

The Senses

- sensory recepts: millions of nuerons that react directly to stimuli fro enviro­nment
- five catego­ries: pain receptors, thermo­rec­eptors, mechan­ore­cep­tors, chemor­ece­ptors, and photor­ece­ptors


- pupil: small opening in middle of iris
- lens: behind iris
- retina: lens focuses light on retina
- two types of photor­ece­ptors:
a. rods - sensitive to light; do not distin­guish colors
b. cones - less sensitive to light; color vision


- vibrations of oval window create pressure waves in cochlea
- semici­rcular canals mantain equili­brium

Smell & Taste

- taste buds: sense organs that detect taste


- skin contains sensory receptors
- greatest density of touch: fingers, toes, and face

Drugs That Affect the Synapse

- stimulants increase heart rate, blood pressure, and breathing rate; increase the release of neurot­ran­smi­tters at some synapses in the brain
- depres­sants slow down heart rate and breathing rate, lower blood pressure, relax muscles, and relieve tension
- cocaine causes the sudden release of a neurot­ran­smitter in the brain called dopamine
- opiates mimic natural chemicals in the brain known as endorp­hins, which normally help to overcome sensations of pain
- marijuana comes from THC and is bad for lungs & memory loss
- alcohol is a depres­sant, and even small amounts of alcohol slow down the rate at which the nervous system functions -> FAS, liver failure, death
- FAS -> heart defects, malformed faces, delayed growth

Drug Abuse

- drug abuse: intent­ional misuse of any drug for nonmedical purposes
- addiction: uncont­rol­lable dependence on a drug

Drug Abuse

- drug abuse: intent­ional misuse of any drug for nonmedical purposes
- addiction: uncont­rol­lable dependence on a drug


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