Ch. 21 Brain Structure and Function Flashcards Preview

Human Biology > Ch. 21 Brain Structure and Function > Flashcards

Flashcards in Ch. 21 Brain Structure and Function Deck (58):
1

nervous system

receives and interprets messages and decides how to respond

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neurons

carry electrical and chemical messages. bundles into nerves

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effectors

responsive tissue to nerve impulses

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nerve impulse

chemical changes as ion concentrations change to pass message

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neurotransmitters

chemicals released from nerve cell

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sensory neurons

carry info to CNS. input detected by sensory receptors

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sensory receptors

neurons or other cells that communicate with sensory neaurons. when stimulated, signals are generated and carried to brain.

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general senses

temperature, pain, pressure, and body position. proprioception. scattered in body

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special senses

smell, taste, equilibrium, hearing, and vision. gound in sense organs in head

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motor neurons

carry info away from CNS to effector tissues

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interneurons

between sensory and motor neurons

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spinal cord

main nerve pathway. contains reflex arc

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reflex

automatic response to stimuli

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reflex arc

prewired circuit of neurons to allow quick reactions to dangerous stimuli

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peripheral nervous system (PNS)

network of nerves outside brain and spinal cord

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glial cells

10x more than neurons in brain. dont carry messages. supply nutrients to neurons, help them repair, and attack invading bacteria

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cerebrum

fills whole upper skull. 2 hemispheres, each with 4 lobes.

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temporal lobe

processes auditory and olfactory information. important for memory and emotion

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occipital lobe

processes visual information from eyes

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parietal lobe

processes touch and involved in self awareness

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frontal lobe

processes voluntary movements. planning and organizing future expressive behavior

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cerebral cortex

wrinkled outer surface of cerebrum

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corpus callosum

bundle of nerve fibers that communicates between hemispheres

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caudate nuclei

paired structures in each hemisphere. part of pathway coordinating movement

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thalamus

relays info between cerebrum and spinal cord. first to receive messages signaling sensations. thalamus suppresses some and enhances others, then are relayed to cerebrum where is processes signals and responds. located between hemispheres

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hypothalamus

located under thalamus. control center for sex drive, pleasure, pain, hunger, thirst, BP, temp. releases hormaones that regulate sperm and egg production and menstrual cycle

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cerebellum

controls balance, muscle movement, coordination. ensures smooth contractions and relaxations. under hemispheres of cerebrum. has hemispheres as well

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brain stem

below thalamus and hypothalamus. governs reflexes and spontaneous functions like heartbeat, resp, swallowing, and coughing

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midbrain

adjusts sensitivity of eyes to light and ears to sound

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pons

bridge. allows messages to travel between cord and brain

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medulla oblongata

controls heart rate. conveys info from cord to parts of brain

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left hemisphere

controls right side of body, speech, reading, and ability to solve math problems

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right hemisphere

controls left side of body, spatial perception (understanding shape and form), and musical and artistic creations

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reticular formation

in medulla. network of neurons radiating toward cerebral cortex. function as filter for sensory input. decides what stimuli require response. prevents brain from reacting to repetitive stimuli (traffic sounds or music while sleeping)

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dendrites

branches off of neuron cell body

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neuron cell body

contains nucleus

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terminal boutons

knobby structures at end of neuron

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axon

long wire like. protected by myelin sheath

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myelin sheath

formed by schwann cells. mostly lipids

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white matter

brain tissue composed of myelinated cells

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nodes of ranvier

small patches uncovered by myelin in between schwann cells. impulse jumps from node to node and 200 mph

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gray matter

brain tissue of unmyelinated cells

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action potential

transmitting signal through breif reversal of electrical charge of nerve cell membrane. wave of electrical current through neuron

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polarization

resting neuron has different charge accross membrane. higher K+ inside than Na+ on outside

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sodium potassium pump

uses ATP to move 3 Na+ out of cell for every 2 K+ put back inside. returns potassium into cell to maintain gradient

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depolarization

decrease of charge difference. activates Na+ channels and lets Na+ enter cel and lowers negative state of polarization. if a critical point is reached, channels open completely and Na+ rushes into cell, eliminating charge difference.

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repolarization

Na+ channels close and K+ channel open, allowing K+ out of cell, making inside of cell more negative than outside

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synapse

space between neurons

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vesicles

sacs at end of terminal boutons filled with neurotransmitters

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synaptic transmission

when signal reaches end of presynaptic neuron, wesicle releases neurotransmitters that diffuse across synapse to specific receptors on membrane of postsynaptic neuron.
once across synapse and in receptor, stimulates rapid change in uptake of Na+ causing depolarization and generating an action potential
cycle occurs until signal reaches effector tissue

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reuptake

reabsorption of neurotransmitters. presynaptic cell allows reentry and reuses them

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neurotransmitters after signal has passed

broken down by enzymes in synapse or taken up by presynaptic cell through reuptake to ensure stimulation stops on postsynaptic cell

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alzheimers

impaired function of neurotransmitter acetylcholine in some neurons

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depression

thought to be imbalance of neurotransmitters serotonin, dopamine, and norepinephrine

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parkinson's

malfunctioning of neurons that produce dopamine. loss of dopamine causes cells to fire without regulation

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ADD

decreased dopamine levels. dopamine suppresses responsiveness to new stimuli. may also have increased number of reuptake receptors on presynaptic neuron and remove dopamine quickly

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ritalin

decreases impact of reuptake receptors, letting dopamine stay in synapse longer

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Adderall and dexedrine

increase levels of dopamine