Exam 2

Question 1

Name the 5 types of sensory receptors as categorized by type of stimulus & describe what each responds to.

Answer 1

1. Mechanoreceptors: respond to mechanical force (touch, pressure, vibration, stretch); 2. Thermoreceptors: respond to temperature changes; 3. Photoreceptors: respond to light (in retina); 4. Chemoreceptors: respond to chemicals (smell, taste, blood chemistry); 5. Nociceptors: respond to pain-causing stimuli (extreme heat, pressure, inflammation).

Question 2

Name the 3 types of sensory receptors by location & describe each.

Answer 2

1. Exteroceptors: respond to stimuli outside the body (touch, pressure, pain, temperature, special senses); 2. Interoceptors (visceroceptors): respond to internal stimuli (chemical changes, tissue stretch); 3. Proprioceptors: respond to internal stimuli but specifically monitor body position/movement (skeletal muscles, joints).

Question 3

Name the 3 types of nonencapsulated sensory receptors & describe:

Answer 3

1. Free nerve endings: detect temperature, pain, itch; 2. Merkel discs: light touch; 3. Hair follicle receptors: detect hair movement.

Question 4

Name the 6 types of encapsulated sensory receptors & describe:

Answer 4

1. Meissner’s corpuscles: light touch in hairless skin; 2. Pacinian corpuscles: deep pressure and vibration; 3. Ruffini endings: deep continuous pressure; 4. Muscle spindles: muscle stretch; 5. Golgi tendon organs: tension in tendons; 6. Joint kinesthetic receptors: monitor stretch in joints.

Question 5

What is the difference between intrinsic and acquired reflexes? Give an example of each.

Answer 5

Intrinsic reflexes are rapid, involuntary, predictable motor responses to stimuli (e.g., knee-jerk reflex). Acquired reflexes are learned through practice or repetition (e.g., driving).

Question 6

Describe how a reflex arc occurs

Answer 6

A stimulus activates a receptor → sensory neuron transmits signal to CNS → integration center processes it → motor neuron carries response signal → effector muscle/gland responds.

Question 7

Explain how a stretch reflex occurs; in the knee jerk response, what happens to the quadriceps & the hamstring?

Answer 7

Stretch receptors in the quadriceps are activated → signal sent to spinal cord → motor neuron stimulates quadriceps to contract → interneuron inhibits hamstring motor neuron, causing hamstring to relax.

Question 8

List all 12 cranial nerves; give the name, number & what each does. Be sure to review roman numerals for each!

Answer 8

I - Olfactory (smell), II - Optic (vision), III - Oculomotor (eye movement, pupil constriction), IV - Trochlear (eye movement), V - Trigeminal (facial sensation, chewing), VI - Abducens (eye movement), VII - Facial (facial expression, taste), VIII - Vestibulocochlear (hearing, balance), IX - Glossopharyngeal (taste, swallowing), X - Vagus (parasympathetic control), XI - Accessory (neck muscles), XII - Hypoglossal (tongue movement).

Question 9

Which cranial nerve is the longest?

Answer 9

X - Vagus nerve.

Question 10

Which cranial nerve is the largest?

Answer 10

V - Trigeminal nerve.

Question 11

Which cranial nerves innervate the tongue?

Answer 11

VII - Facial, IX - Glossopharyngeal, XII - Hypoglossal.

Question 12

Which cranial nerves innervate the eyes?

Answer 12

III - Oculomotor, IV - Trochlear, VI - Abducens.

Question 13

Which cranial nerves are involved in the ANS?

Answer 13

III - Oculomotor, VII - Facial, IX - Glossopharyngeal, X - Vagus.

Question 14

Where do all the cranial nerves originate?

Answer 14

All except I (Olfactory) and II (Optic) originate from the brainstem.

Question 15

How many pairs of spinal nerves are there?

Answer 15

31 pairs.

Question 16

Why is there a C8 spinal nerve?

Answer 16

Because there are 8 cervical nerves but only 7 cervical vertebrae; C8 exits below C7 and above T1.

Question 17

What are dorsal root ganglia?

Answer 17

Clusters of sensory neuron cell bodies located in the dorsal root of spinal nerves.

Question 18

Where do nerve roots connect to the spinal cord?

Answer 18

Nerve roots attach to the spinal cord at the dorsal (sensory) and ventral (motor) roots.

Question 19

Which nerve root carries motor? Sensory?

Answer 19

Dorsal root = sensory; Ventral root = motor.

Question 20

How do the nerve roots relate to the spinal nerves and to the spinal nerve rami?

Answer 20

The dorsal and ventral roots merge to form spinal nerves, which then split into rami (dorsal and ventral branches).

Question 21

Do the spinal nerves carry motor or sensory? What about the rami?

Answer 21

Spinal nerves carry both motor and sensory fibers; Rami also carry both types.

Question 22

What do the ventral rami innervate?

Answer 22

Ventral rami innervate the limbs and anterior trunk.

Question 23

What do the dorsal rami innervate?

Answer 23

Dorsal rami innervate the posterior trunk muscles and skin.

Question 24

What is a nerve plexus & why is it important?

Answer 24

A network of intersecting nerves from ventral rami that allows for redundancy and coordination in innervation, especially for limbs.

Question 25

Which nerve roots innervate the phrenic nerve?

Answer 25

C3, C4, and C5 nerve roots ("C3, 4, 5 keep the diaphragm alive").

Question 26

From medial to lateral, list the subdivisions of the brachial plexus (there are 5):

Answer 26

Roots, Trunks, Divisions, Cords, Branches.

Question 27

What are dermatomes?

Answer 27

Skin areas innervated by sensory fibers of a single spinal nerve.

Question 28

Describe the autonomic nervous system (ANS): is it motor or sensory, what does it innervate?

Answer 28

Motor; it innervates smooth muscle, cardiac muscle, and glands.

Question 29

How do the effectors of the ANS and the somatic nervous system differ?

Answer 29

Somatic system innervates skeletal muscles (voluntary); ANS innervates smooth and cardiac muscle and glands (involuntary).

Question 30

How do the efferent pathways & ganglia of the ANS & somatic nervous system differ (how many neurons, what are the axons like, what neurotransmitters are used, which has faster conduction)?

Answer 30

Somatic: single motor neuron, thick myelinated axon, ACh, fast conduction. ANS: two-neuron chain (preganglionic and postganglionic), thin lightly or unmyelinated axons, ACh and norepinephrine, slower conduction.

Question 31

What are the two divisions of the ANS? Describe their key functions (what is each one’s “catchphrase?”).

Answer 31

Sympathetic (fight or flight) and Parasympathetic (rest and digest).

Question 32

Describe the difference between the sites of origin & locations of ganglia for the two divisions of the ANS:

Answer 32

Sympathetic: thoracolumbar origin, ganglia near spinal cord. Parasympathetic: craniosacral origin, ganglia near or in target organs.

Question 33

What are parasympathetic actions throughout the body?

Answer 33

Constriction of pupils, decreased heart rate, increased digestive activity, urination, erection.

Question 34

What are sympathetic actions throughout the body?

Answer 34

Dilated pupils, increased heart rate, decreased digestion, release of glucose, sweating, ejaculation.

Question 35

What is the difference in the breadth & duration of response between the sympathetic & parasympathetic divisions?

Answer 35

Sympathetic responses are more widespread and longer-lasting due to hormone release (e.g., adrenaline); Parasympathetic responses are more localized and short-lived.