Nervous System

structures that make up a neuron

axon, dendrite, myelin sheath, cell body, axon terminal, Schwann cell

dendrite

conducts impulses and receives impulses toward cell body

cell body

middle, dedrite sends signal to

axon

conducts impulses away from cell body

Schwann cell

makes the myelin sheath, longer section of axon

axon terminal

end of axon

myelin sheath

fatty substance that insulates axons

what are the general regions of the brain?

diencephalon, cerebellum, cerebrum

Diencephalon

Contains thalamus and hypothalamus and pineal gland

cerebellum

coordinates all motor activity

cerebrum

largest part of brain, perception, reasoning, and memory

oligodendrocytes

form myeline sheath that speeds up neuron transmission

astrocytes

star shaped, anchor neurons to blood vessels

microglia

act as main source of immune defense against invading microbes in CNS

ependymal cells

produce cerebrospinal fluid

steps in a reflex arc

1. Sensory reception(receptor)

2. Afferent neuron

3. Association center

4. Efferent neuron

5. Effector (muscle)

what ions flow into the cell during action potential?

-depolarization: Na+ enter cell

what ions flow out of the cell during action potential?

falling phase: K+ ions leave the inner cell + hyper polarization

how are neurotransmitters released from the synaptic vesicles during transmission of a nerve impulse?

an action potenial reaches the presynaptic vesicles, causing calcium ion gates to enter the terminal, which causes the vesicles to fuse with the presynaptic membrane, releasing neurotransmitters into synaptic cleft

what are the two sections of the PNS?

somatic nervous system- voluntary

automatic nervous system- involuntary

what is the function of cerebral spinal fluid?

cushions CNS, delivers nutrients, removes wastes

gyrus

surface folds of brain

sulci

shallow grooves in brain

dura mater

outermost protective layer, made of connective tissue in meninges

pia mater

thin inner layer of meninges

arachnoid mater

middle layer of the meninges