PNS and reflex activity (ch 13)

Question 1

the CNS sends info

Answer 1

out

Question 2

effectors are activated when

Answer 2

a NT is secreted onto an effector organ

Question 3

where does innervation of skeletal muscle take place

Answer 3

at the level of the neuromusculojunction (NMJ)

Question 4

what is the neurotransmitter involved in skeletal muscle innervation

Answer 4

Acetylcholine (ACh)

Question 5

steps of skeletal muscle innervation

Answer 5

nerve impulse reaches axon terminal to release ACh, which binds to receptors and results in excitation (movement of Na+/K+ across the membrane, depolarization of muscle cell), end plate potential triggers an AP in the cell, resulting in contraction

Question 6

autonomic motor endings and visceral effectors are _____ than somatic junctions

Answer 6

simpler

Question 7

steps of visceral muscle and gland innervation

Answer 7

branches form synapses en passant via varicosities, two different NTs (ACh and NE(norepinephrine)) act indirectly via second messenger systems

Question 8

compared to somatic, visceral motor responses are

Answer 8

slower

Question 9

in skeletal muscle, the cerebellum and basal nuclei are

Answer 9

the main coordinators of muscle control

Question 10

_____ motor behavior depends on _____ patterns of control

Answer 10

complex, complex

Question 11

what are the three levels of motor control in skeletal muscle

Answer 11

segmental, projection, pre-command

Question 12

the segmental level of motor control is

Answer 12

the lowest level of motor hierarchy

Question 13

the segmental level involves

Answer 13

reflexes, spinal cord circuits, and central pattern generators (CPGs)

Question 14

T/F: the segmental level is not conscious

Answer 14

true

Question 15

CPGs are

Answer 15

segmental circuits that activate networks of ventral horn neurons to stimulate specific groups of muscles

Question 16

the projection level of motor control consists of

Answer 16

the precentral gyrus (cortex, brain stem motor areas)

Question 17

the cortex contains _____ that initiate the _____

Answer 17

upper motor neurons, direct (pyramidal) system

Question 18

the brain stem motor areas oversee the _____

Answer 18

indirect (extrapyramidal) system

Question 19

the direct pyramidal system involves

Answer 19

voluntary movement

Question 20

the indirect (extrapyramidal) system involves

Answer 20

reflexes and CPGs

Question 21

projection level motor pathways send information to _____ and let _____ know what is happening

Answer 21

lower motor neurons, higher command levels

Question 22

the precommand level is

Answer 22

the highest level of motor control

Question 23

what occurs in the precommand level

Answer 23

neurons in the cerebellum and basal nuclei control outputs of the cortex and brainstem

Question 24

functions of the cerebellum

Answer 24

• act on motor pathways through projection areas located in the brainstem
• act on motor cortex via the thalamus (sensory relay station)

Question 25

functions of the basal nuclei

Answer 25

- at rest, acts to inhibit motor centers - when you need to move of change movement, it stops motor inhibition

Question 26

parkinson's results in

Answer 26

a resting tremor and stiffness/lack of movement

Question 27

a reflex is

Answer 27

a rapid, predictable, involuntary motor response to a given stimulus

Question 28

two categories of reflexes

Answer 28

autonomic and somatic

Question 29

there are more of this type of reflex

Answer 29

autonomic

Question 30

autonomic reflexes involve

Answer 30

smooth muscle, cardiac muscle, and glands

Question 31

examples of autonomic reflexes

Answer 31

sweating when hot, increasing heart rate when exercising, salivating when eating

Question 32

somatic reflexes involve

Answer 32

skeletal muscle

Question 33

examples of somatic reflexes

Answer 33

knee jerk, shivering, cough, sneeze

Question 34

steps of the reflex arc

Answer 34

receptor picks up a stimulus, sensory neurons carry the info (APs) to the CNS, integration of synapses occurs in the CNS, motor neurons carry APs away from the CNS, effector gives a response

Question 35

speed of skeletal muscle

Answer 35

quick

Question 36

parts of the muscle stretch reflex

Answer 36

muscle spindle (receptor), alpha motor neurons (outside)

Question 37

parts of the muscle spindle

Answer 37

- intrafusal muscle fibers (made of skeletal muscle cells) - sensory neurons - motor neurons

Question 38

types of sensory neurons and their functions

Answer 38

- type I responds to stretch speed - type II responds to stretch degree/amount

Question 39

function of gamma motor neurons

Answer 39

adjust spindle/intrafusal therefore adjusting the spindle response

Question 40

function of alpha motor neurons

Answer 40

acts on extrafusal fibers

Question 41

alpha and gamma motor neurons are stimulated _____ so _____

Answer 41

together, the spindle can still respond at various muscle lengths

Question 42

events of the muscle stretch reflex

Answer 42

stretched muscle increases APs to CNS via a sensory neuron, sensory neuron synapses with alpha motor neuron of the stretched muscle and inhibitory interneuron to inhibit the alpha motor neuron of the antagonist muscle, stretched muscle contracts and the antagonist relaxes

Question 43

example of muscle stretch reflex

Answer 43

knee jerk reflex (knee/quads contract, hamstrings relax)

Question 44

examples of somatic reflexes

Answer 44

- withdrawal reflex - crossed extensor reflex - golgi tendon organ reflex - superficial spinal reflexes (babinski)

Question 45

the withdrawal reflex is

Answer 45

pulling away from painful stimuli

Question 46

the crossed extensor reflex is

Answer 46

where one side flexes and the other side extends

Question 47

the crossed extensor reflex is

Answer 47

where one side flexes and the other side extends

Question 48

the golgi tendon reflex

Answer 48

acts to inhibit the muscle from pulling too hard on a tendon

Question 49

the babinski reflex is

Answer 49

when the toes flex in response to a stimulus on the bottom of the foot

Question 50

the babinski reflex develops around age

Answer 50

1-2

Question 51

examples of autonomic reflexes

Answer 51

digestive - stomach stretch moves colon cardiovascular - heart rate, BP, vessel flow integument/skin - sweat, goosebumps senses (eyes) - pupil, focus urinary - bladder contracts reproductive - childbirth, orgasm

Question 52

what information is gained by testing the reflexes

Answer 52

- function of nerves - spinal cord/brain function at various levels - degree of stimulation or inhibition of motor areas from brain