Unit 5 Nervous system

Question 1

innate reflexes vs acquired reflexes

Answer 1

Innate: an automatic instinctive unlearned reaction to a stimulus
Acquired: an acquired response that is under the control of (conditional on the occurrence of) a stimulus

Question 2

basic components of reflex arc

Answer 2

recpector, sensory neurons, integration center, motor neuron, and effector

Question 3

Monosynaptic reflex arc

Answer 3

one synapse, no interneuron

Question 4

polysynaptic reflex arc

Answer 4

2 or more synapses

Question 5

intersegmental relex arc

Answer 5

a reflex involving several segments of spinal cord

Question 6

why do we need polysynaptic reflexes?

Answer 6

for withdrawl responses

Question 7

ipsilateral vs contralateral

Answer 7

ispilateral: same side
contralateral: oposite sides

Question 8

what stimulates a stretch reflex (deep tendon reflex)?

Answer 8

an external force (load) or internal force (neurons being stimulated from within)

Question 9

reciprocal inhibition

Answer 9

prevents muscles from working against each other when external loads are encountered

Question 10

Answer 10

flexor withdrawal reflex

Question 11

stretch reflex

Answer 11

causes contraction of a skeletal muscle in response to the stretching of the same muscle. It occurs via a monosynaptic reflex arc. An example of a stretch reflex is the patellar reflex (knee jerk).

Question 12

tendon reflex

Answer 12

when a tendon is stretched, the muscle pulling the tendon relaxes. It is a polysynaptic reflex arc. The tendon reflex can cause you to drop a heavy weight when tension is great.

Question 13

Flexor (withdrawl) reflex

Answer 13

causes you to immediately withdraw from a painful stimulus. This reflex involves a polysynaptic reflex arc, and like the first two, it is ipsilateral

Question 14

crossed extensor reflex

Answer 14

when you step on a tack you may also lose your balance if your body weight shifts to the other foot. In addition to initiating the withdrawal of the limb, the pain impulse initiates a crossed extensor reflex to activate the muscles on the other side of the body and maintain balance. This is a polysynaptic reflex arc. Unlike the first three spinal reflexes, this reflex involves a contralateral response

Question 15

brain stem function

Answer 15

The brain stem is responsible for regulating most of the body’s automatic functions that are essential for life.

Question 16

3 parts of brain stem

Answer 16

midbrain, pons, medulla oblongata

Question 17

Spinothalamic pathway

Answer 17

conscious info (itch, tickle, pain, crude touch)
crosses in spinal cord, synapes in spinal cord and thalamus

Question 18

Posterior column medial lemniscus pathway

Answer 18

(fine touch, pressure, vibration, proprioception)
synapses and crosses at medulla oblongata, 2nd synapse in thalamus

Question 19

spinocerebellar pathway

Answer 19

proprioception, 1st synapse in the spinal cord, ends in the cerebellum, not consciously perceived, and doesn’t cross over, only 2 neurons

Question 20

what are some cranial nerve reflexes?

Answer 20

gag reflex, corneal reflex (blink)