A&P Lab Exercise 16

Question 1

What is a reflex arc?

Answer 1

The pathway over which an impulse travels

Question 2

What is the simplest type of nerve pathway found in the body?

Answer 2

Reflex arc

Question 3

What are the five components of a reflex arc?

Answer 3

1. Receptor
2. Sensory neuron
3. Integrating center
4. Motor neuron
5. Effector

Question 4

What is a reflex?

Answer 4

A rapid, automatic response to a stimulus

Question 5

What are the two types of reflexes?

Answer 5

Visceral or autonomic

Question 6

What is a cranial reflex?

Answer 6

It involves the cranial nerves and an integrating center in the brainstem

Question 7

What are somatic reflexes?

Answer 7

Those that involve the contractions of skeletal muscles

Question 8

Are somatic reflexes cranial or spinal?

Answer 8

Spinal reflexes

Question 9

What is a receptor?

Answer 9

A structure that reacts to a stimulus such as: pressure, pain, heat, cold, light, or sound. The nerve impulse begins with the receptor

Question 10

What is a sensory neuron?

Answer 10

The neuron that conducts the afferent impulse from the receptor to the spinal cord or to the brain

Question 11

What is an integrating center?

Answer 11

The area in the spinal cord or brain where the incoming impulse is transmitted to other neurons. The center usually contains association neurons (interneurons)

Question 12

What is a motor neuron?

Answer 12

The neuron that conducts the efferent impulse from the integrating center to the part of the body that will respond

Question 13

What is the effector?

Answer 13

The muscle fiber of the body that responds to the efferent impulse by contracting or the gland that responds to the impulse by secreting.

Question 14

Is a motor neuron afferent or efferent?

Answer 14

Efferent

Question 15

Is a sensory neuron afferent of efferent?

Answer 15

Afferent

Question 16

What is reciprocal inhibition?

Answer 16

During a knee jerk reflex, the stretch reflex contracts the quads but inhibits and relaxes the hamstrings

Question 17

What would happen if both muscles contracted?

Answer 17

No movement would occur

Question 18

How many neurons are involved in the stretch reflex?

Answer 18

2

Question 19

Is a stretch reflex mono/polysynaptic?

Answer 19

Monosynaptic

Question 20

What is the sensor that detects that the muscle is being stretched?

Answer 20

Muscle spindle

Question 21

Which side of the body would be affected by a spinal cord injury?

Answer 21

Both sides

Question 22

What side of the body would be affected by damage to the right cortex?

Answer 22

Left side of the body

Question 23

What is clonus?

Answer 23

Oscillating movement that results from the hammer stimulation

Question 24

What are the steps to the stretch reflex?

Answer 24

1. Extensor muscle stretched
2. Muscle spindle stimulated
3. Primary afferent neuron excited
4. Afferent neuron stimulates alpha motor neuron to extensor muscle
5. Alpha motor neuron stimulates extensor muscle to contract
6. Afferent neuron stimulates inhibitory interneuron
7. Interneuron inhibits alpha motor neuron to flexor muscle
8. Flexor muscle (antagonist) relaxes

Question 25

What is the Babinski reflex?

Answer 25

The foot when tickled should curl the toes or point down, but in the Babinski reflex, the foot flexes up and the toes fan out (indicating corticospinal tract damage)