Reflexes

Question 1

What is the basic structural unit of the nervous system?

Answer 1

Neuron

Question 2

What is the basic funcitonal unit of the nervous system?

Answer 2

Reflex arc - the mslalest, simplest portion capable of receiving a stimulus and producing a reponse

Question 3

5 components of the reflex arc

Answer 3

1) sensory receptor
20 sensory neuron
3) interneuron
4) motor neuron
5) effector organ

Question 4

reflex

Answer 4

automatic response to a stimulus produced by a reflex arc. Occurs w/o conscious thought

Question 5

Autonomic v. somatic reflexes

Answer 5

Autonomic - responsible for maintaining blood pressure, blood CO2 levels, etc.
Somatic - move the body away from stimuli that would cause tissue damage or keep the body from falling or moving bc of external forces.

Question 6

Monosynaptic reflexes v. polysynaptic reflexes

Answer 6

Mono - simple neural pathways - sensory neurons synapse directly with motor neurons
Poly - more complex pathways, must synapse w/ interneurons

Question 7

3 major spinal cord reflexes

Answer 7

Stretch reflex
Golgi tendon reflex
Withdrawal reflex

Question 8

Stretch reflex

Answer 8

simplest reflex.
Muscle contracts in response to a stretching force.
Eg - knee-jerk reflex

Question 9

Golgi tendon reflex

Answer 9

Prevent contracting muscles from applying excessive tension to tendons.

Stimulates inhibitory neurotransmitters to the muscles, causing it to relax, which reduces the tension applied to the muscle.

Protects muscles and tendons from damage caused by excessive tension. EG - weight lifters who suddenly drop a heavy weight

Question 10

Golgi tendon organs

Answer 10

Encapsulated nerve endings, located near the muscle-tendon junction.

Have high threshold, only sensitive to intense stretch

Question 11

Withdrawal reflex

Answer 11

remove a limb or another body part from a painful stimulus.

Question 12

Reciprocal innervation

Answer 12

reinforces the efficiency of withdrawal reflex by coordinating the contraction of flexor muscles and relaxation of opposing extensor muscles.

Question 13

Crossed extensor reflex

Answer 13

Associated w/ withdrawal reflex
Occurs on opposite side of the body from stimulus
Helps prevent falls (eg - if you step on a tack, you shift your weight to the other limb so you don’t fall)