The Nervous System

Question 1

nervous system functions

Answer 1

sensory input
integration of sensory input
homeostasis
mental activity
muscle control

Question 2

Nerve impulse

Answer 2

the electrical charge that passes btwn neurons until it reaches a terminal

Question 3

polar

Answer 3

more negative

Question 4

resting membrane charge

Answer 4

-77 mv

Question 5

at what value is an action potential generated

Answer 5

-55 mv

Question 6

graded potential

Answer 6

a local event (involving one neuron) where there is an incomplete depolarization and no AP is generated

Question 7

Propagation

Answer 7

movement of AP down the axon

Question 8

myelin sheath

Answer 8

the covering on an axon that speeds up propagation

Question 9

nodes of ranvier

Answer 9

the gaps between myelin sheath

Question 10

saltatory conduction

Answer 10

jumping of an impulse between the nodes of ranvier

Question 11

how does diameter affect propagation

Answer 11

larger diameter neurons conduct faster impulses

Question 12

absolute refractory period

Answer 12

point at which the cell has fully depolarized, making it impossible for action potential to travel the opposite way up the axon

Question 13

synapse

Answer 13

the gap btwn neurons, communication site

Question 14

synapse components

Answer 14

1. axon terminals of pre-synaptic neuron
2. receptor sites of post-synaptic neuron
3. synaptic cleft

Question 15

which neurotransmitters are used for neurons ?

Answer 15

acetylcholine (primary for motor neurons of skeletal muscle)
norepinephrine + epinephrine used fir sympathetic nerve endings

Question 16

what are the two types of incoming post-synaptic response, and what do they lead to?

Answer 16

1. excitatory: membrane depolarization, influx of Na+
2. inhibitory: hyper polarization, influx of k+

Question 17

summation

Answer 17

an adding of all EPSP and IPSP’s, performed by the axon hillock

Question 18

where on the muscles do NT’s bind?

Answer 18

receptor sarcolemmas of the muscle

Question 19

neuromuscular junction

Answer 19

space between axon terminal motor end plates and the muscle fiber

Question 19

refractory period

Answer 19

time during depolarization where muscle fibers are unable to respond to other stimuli

Question 20

Nervous system organization

Answer 20

-central: brain and spine
-peripheral
-afferent/sensory
-efferent/motor:
-somatic
-autonomic:
-sympathetic
-parasympathetic

Question 21

lobes of the cerebrum

Answer 21

-frontal
-occipital
-parietal
-temporal
-insular (emotion/self perception, sensorimotor processing)
-cerebral cortex (memory, thinking, learning, reasoning)
-motor cortex (voluntary muscle control, skill acquisition)

Question 22

diencephalon

Answer 22

portion of the brain which contains the thalamus (sensory input center) and hypothalamus (endocrine control, autonomic NS, homeostasis)

Question 23

cerebellum

Answer 23

portion of the brain which coordinates complex movement, accounts for body position/timing

Question 24

brainstem

Answer 24

connects cerebrum to spinal cord, houses all sensory and motor nerves, contains pons, midbrain, and medulla

Question 25

spinal cord

Answer 25

connects to midbrain, allows for 2 way nerve impulse conduction

Question 26

sensory fibers

Answer 26

afferent, carry signals from sensory receptors to higher levels of CNS (dorsal root)

Question 27

motor fibers

Answer 27

efferent, carry impulses from brain to spinal cord to target organs (ventral root)

Question 28

joint kinesthetic receptors

Answer 28

receptors of the sensory NS w/in the joint capsule, sensitive to joint angle changes

Question 29

muscle spindles

Answer 29

receptors of the sensory NS, relay info ab how much a muscle is stretched

Question 30

Golgi tendon organs

Answer 30

receptors of the sensory NS, measure tension applied to tendons

Question 31

autonomic nervous system

Answer 31

innervates involuntary muscle/glands

Question 32

sympathetic nervous system

Answer 32

prepares the body for exercise by increasing HR, respiration, blood pressure thru broncho and vaso dilation

Question 33

parasympathetic ns

Answer 33

active during rest, decreases HR, respiration , blood pressure thru broncho and vaso restriction

Question 34

dual innervation

Answer 34

the autonomic NS is innervated with both sympathetic and parasympathetic divisions

Question 35

cholinergic neurons

Answer 35

bind acetylcholine for use by the ANS, can be either nicotinic or muscarinic

Question 36

adrenergic neurons

Answer 36

bind norepinephrine and epinephrine for use by the ANS

Question 36

what reflex lowers HR?

Answer 36

parasympathetic of vagus nerve

Question 37

what reflex raises HR?

Answer 37

symp reflex of cardiac accelerator

Question 38

sensory input process

Answer 38

1. receptors detect sensation 2. sensory input travels to CNS (via afferent neurons) 3. Impulse terminates in one of 5 integration centers

Question 39

what are the 5 integration centers?

Answer 39

1. spinal cord (simple reflex) 2. lower brain stem (subconscious motor rxns) 3. cerebellum (subconscious gross motor) 4. thalamus (conscious movement, response to stimuli) 5. cerebral cortex (learned response)

Question 40

reflex arc

Answer 40

1. sensory impulse terminates in the spinal cord 2. impulse is transmitted to motor neuron 3. impulse transmitted to muscle for involuntary reaction

Question 41

what receptors initiate reflex response

Answer 41

proprioceptors and chemoreceptors

Question 42

chemoreceptors

Answer 42

specialized free nerve endings, - muscle spindles: info on muscle length - Golgi tendon organs: muscle tension

Question 43

proprioceptors

Answer 43

same as joint kinesthetic receptors, sense body position and limb movement, divided into free nerve endings, pacinian corpuscles, and Golgi receptors

Question 44

Muscle spindles

Answer 44

type of chemoreceptor found between muscle fibers, sends info about length, contractile state, rate of change, resist over stretching

Question 45

Golgi tendon organs

Answer 45

sensory receptors imbedded in tendons, sensitive to tension in the muscle, inhibit agonists and excite antagonists when stimulated by excessive tension