Dat Bio Ch 7 Nervous System

Front 1

function of the nervous system

Back 1

to receive and respond to stimuli from internal and external environments

Front 2

functioning unit of the nervous system

Back 2

neuron

Front 3

what do neurons convert stimuli into

Back 3

electrochemical signals, faster response than endocrine system

Front 4

structure of neuron

Back 4

elongated, having a cell body, axon, and several dendrites

Front 5

what is the function of dendrites

Back 5

receive info and transmit it to the cell body

Front 6

function of soma

Back 6

cell body, contains nucleus and controls metabolic activity of neuron

Front 7

function of axon

Back 7

transmits impulses away from the cell body

Front 8

axon insulating sheath, function

Back 8

myelin allows axons to conduct impulses faster

Front 9

glial cell function

Back 9

produce myelin

Front 10

glial cells of CNS

Back 10

oligodendrocytes

Front 11

glial cells of PNS

Back 11

Schwann cells

Front 12

function of synaptic terminals

Back 12

release neurotransmitters into synapse, the gap between end of axon and next neuron's dendrites

Front 13

action potential

Back 13

impulses that travel the length of the axon and signal release of neurotransmitters

Front 14

resting potential

Back 14

potential difference between extracellular space and intracellular space

Front 15

typical resting membrane potential

Back 15

-70 millivolts

Front 16

at resting potential, which side of the membrane is negative?

Back 16

inside the neuron

Front 17

what maintains the polarized state of the neuron?

Back 17

active transport by a Na+/K+ pump

Front 18

which ion is permeable to the neuron membrane? which is impermeable?

Back 18

permeable: K+

impermeable: Na+

Front 19

How is the resting negative charge inside the cell maintained?

Back 19

the Na/K pump uses ATP to push 3 Na out for every 2 K brought in. K then diffuses out of the cell down its concentration gradient, leaving the inside of the cell negative.

Front 20

what is threshold?

Back 20

the minimum membrane potential level at which an action potential is initiated

Front 21

What causes a neuron to reach threshold?

Back 21

It receives impulses from other neurons, causing it to become excited or depolarized.

Front 22

When does a voltage-gated Na+ channel open?

Back 22

as a response to depolarization, begins an action potential by allowing Na+ to rapidly enter the cell down its electrochemical gradient

Front 23

What happens during repolarization?

Back 23

voltage-gated K+ channles open, allowing K+ to rush out of the cell down its electrochemical gradient. the cell interior returns to a more negative potential

Front 24

hyperpolarization

Back 24

when repolarization makes the neuron more negative than it was at resting potential

Front 25

refractory period

Back 25

period of time that the neuron can't initiate another action potential

Front 26

how is the action potential an all-or-none response?

Back 26

if threshold is reached an action potential is produced with a consistent size and duration. maximum nerve firing or none at all

Front 27

how is stimulus intensity encoded?

Back 27

more intensity = greater frequency of action potentials

Front 28

what determines the speed at which an action potential travels down the axon

Back 28

greater diameter = faster
more myelin = faster

Front 29

nodes of Ranvier

Back 29

gaps between myelin segments

Front 30

what is the location of a synapse

Back 30

gap between axon terminal of presynaptic neuron and dendrites of the postsynaptic neuron

Front 31

neurons only communicate with other neurons. T/F?

Back 31

false. postsynaptic cells may be other than neurons, such as muscle or glands. these are called effector cells

Front 32

how are neurotransmitters released

Back 32

action potential arrives at the axon terminal, synaptic vesicles are depolarized, they fuse with the presynaptic membrane and release neurotransmitters

Front 33

what are the fates of neurotransmitters

Back 33

absorbed into postsynaptic neuron to be recycled or degraded, degraded by an enzyme in the synapse, diffuse out of the synapse

Front 34

effect of curare

Back 34

blocks postsynaptic acetylcholine receptors from receiving the neurotransmitter, results in paralysis by blocking nerve impulses to muscles

Front 35

effect of botulism toxin

Back 35

prevent release of acetcholine from presynaptic membrane, results in paralysis

Front 36

effect of anticholinesterases

Back 36

inhibit acetylcholinesterase from degrading acetylcholine in synapse. loss of coordinated muscle contractions

Front 37

afferent neurons

Back 37

sensory neurons

Front 38

efferent neurons

Back 38

motor neurons

Front 39

interneurons

Back 39

linking neurons, link sensory and motor neurons to the brain and spinal cord

Front 40

nerve structure

Back 40

bundle of axons

Front 41

plexus

Back 41

network of nerve fibers

Front 42

ganglia

Back 42

cluster of neuronal cell bodies in PNS, called nuclei in CNS

Front 43

central nervous system components

Back 43

brain and spinal cord

Front 44

gray matter

Back 44

outer portion of brain made up of cell bodies

Front 45

white matter

Back 45

inner portion of brain made up of myelinated axons

Front 46

forebrain components

Back 46

telencephalon and diencephalon

Front 47

cerebral cortex

Back 47

part of telencephalon
processes and integrates sensory input and motor responses.
important for memory and creative thought

Front 48

olfactory bulb

Back 48

located in cerebral cortex

reception and integration of olfactory input

Front 49

parts of diencephalon

Back 49

thalamus and hypothalamus

Front 50

thalamus

Back 50

relay and integration center for spinal cord and cerebral cortex

Front 51

hypothalamus

Back 51

controls visceral functions such as hunger, thirst, sex drive, water balance, blood pressure, and temp regulation. also important in endocrine system

Front 52

midbrain

Back 52

relay center for visual and auditory impulses. part of motor control

Front 53

hindbrain parts

Back 53

cerebellum, pons, medulla

Front 54

cerebellum

Back 54

modulates motor impulses initiated by the cerebral cortex.
balance, hand-eye coordination, timing of rapid movements

Front 55

pons

Back 55

relay center between cerebral cortex and cerebellum

Front 56

medulla oblongata

Back 56

controls vital functions
breathing, heart rate, gastrointestinal activity

Front 57

brainstem

Back 57

midbrain, pons, medulla

Front 58

spinal cord

Back 58

conduit for sensory input to the brain and motor impulses from the brain. can integrate simple motor reflexes by itself

Front 59

dorsal horn

Back 59

spinal cord sensory input entrance

Front 60

ventral horn

Back 60

motor information exit of spinal cord

Front 61

peripheral nervous system

Back 61

nerves and ganglia

Front 62

divisions of PNS

Back 62

somatic and autonomic nervous systems

Front 63

SNS

Back 63

voluntary movement of skeletal muscles

Front 64

ANS

Back 64

involuntary control of body's internal environment
controls cardiac and smooth muscle

Front 65

subdivisions of ANS

Back 65

sympathetic nervous system and parasympathetic nervous system

Front 66

sympathetic nervous system

Back 66

fight or flight response
norepinephrine is primary neurotransmitter

Front 67

parasympathetic nervous system

Back 67

rest and digest, conserves energy and restores body to resting activity after exertion

acetylcholine is primary neurotransmitter

Front 68

vagus nerve

Back 68

primary parasympathetic nerve

Front 69

structure of the eye

Back 69

sclera - white of the eye
choroid layer - supplies retina with blood
retina - contains photoreceptors
cornea - transparent pupil cover, focuses light
pupil - opening that allows light in
iris - controls size of pupil according to light intensity
lens - focuses image on retina
ciliary muscles - control lens

Front 70

cones

Back 70

respond to high-intensity illumination, color sensitive

Front 71

rods

Back 71

detect low-intensity light, important in night vision

Front 72

rhodopsin

Back 72

rod pigment

Front 73

why does the eye have a blind spot?

Back 73

area of the eye where the optic nerve exits, no photoreceptors

Front 74

fovea

Back 74

high cone density area of retina, important for high-acuity vision

Front 75

vitreous humor

Back 75

eye jelly, keeps eye in proper shape and gives optimal light transmission

Front 76

myopia

Back 76

nearsightedness, image is focuses in front of the retina

Front 77

hyperopia

Back 77

farsightedness, image is focused behind the retina

Front 78

astigmatism

Back 78

irregularly shaped cornea

Front 79

cataracts

Back 79

opaque lenses, can cause blindness

Front 80

glaucoma

Back 80

increase pressure in eye due to blocking of aqueous humor outflow

Front 81

outer ear

Back 81

auricle and auditory calan

Front 82

middle ear

Back 82

tympanic membrane (eardrum), ossicles (malleus, incus, and stapes)

Front 83

inner ear

Back 83

cochlea and vestibular apparatus

Front 84

path of sound through ear

Back 84

auditory canal, vibrates tympanic membrane, vibrates ossicles and is amplified, through oval window into cochlea, vibrations create waves in fluid, stimulating hair cells in basilar membrane, converted to action potentials sent to auditory nerve to brain

Front 85

function of vestibular apparatus

Back 85

maintaining equilibrium

Front 86

do protozoa have a nervous system?

Back 86

no organized nervous system in unicellular organisms

Front 87

nervous system of cnidarians

Back 87

nerve net - simple network of nerve cells with little centralization

Front 88

nervous sytem of annelids

Back 88

primitive CNS with a ventral nerve cord, "brain" of fused ganglia, and definite nerve pathways

Front 89

nervous system of arthropods

Back 89

similar to annelids, have specialized sense organs such as simple or compound eyes and a tympanum