Chapter 13

Question 1

The three ways to classify sensory receptors

Answer 1

1. by the type of stimulus they detect
2. by their body location
3. by their structural complexity

Question 2

Mechanoreceptors (type)

Answer 2

respond to mechanical force such as touch, pressure (including blood pressure), vibration, and stretch

Question 3

Thermoreceptors (type)

Answer 3

respond to temperature changes

Question 4

Photoreceptors (type)

Answer 4

such as those of the retina of the eye, respond to light

Question 5

Chemoreceptors (type)

Answer 5

respond to chemicals in solution (molecules smelled or tasted, or changes in blood or interstitial fluid chemistry)

Question 6

Nociceptors (type)

Answer 6

respond to potentially damaging stimuli that result in pain.

Question 7

Exteroceptors (location)

Answer 7

sensitive to stimuli arising outside the body

Question 8

Interoceptors a.c. visceroceptors (location)

Answer 8

respond to stimuli within the body

Question 9

Proprioceptors (location)

Answer 9

Respond to internal stimuli
* Occur in skeletal muscles, tendons, joints, ligaments, and connective tissue
coverings of bones and muscles
* Constantly advise the brain of our body movements by monitoring how much the
organs containing these receptors are stretched

Question 10

Receptors for special senses

Answer 10

vision, hearing, equilibrium, smell, & taste) - special sense organs

Question 11

Nonencapsulated (Free) Nerve Endings (Receptor Structure)

Answer 11

• abundant in epithelia & c.t.
• Mostly nonmyelinated & small diameter
  -Thermoreceptors: Cold (10-40C & superficial dermis) & Heat (32-48C & deep dermis)
• Nociceptors
• Light pressure receptors: Tactile (Merkel discs) & Hair follicle receptors (detect bending of hairs)

Question 12

Encapsulated nerve endings (structure)

Answer 12

• all consist of one or more fiber terminals of sensory neurons enclosed in a c.t. capsule.
• All are mechanoreceptors

Question 13

Types of Encapsulated nerve endings

Answer 13

Muscle spindles - detect muscle stretch & reflex that resists stretch
Tendon organs - initiates a reflex that causes a contracting muscle to relax

Question 14

somatosensory system

Answer 14

the part of the sensory system dealing with reception in the body walls & limbs; receives inputs from exteroceptors, proprioceptors, & interoceptors

Question 15

Pain Threshold

Answer 15

Perception of pain at roughly the same stimulus intensity ( we all share this)

Question 16

Pain tolerance

Answer 16

varies widely

Question 17

Visceral pain

Answer 17

Usually a vague sensation of dull aching, gnawing, or burning
Important stim for visceral pain are extreme stretching of tissue, ischemia (low blood flow), irritating chemicals, & muscle spasm

Question 18

Referred pain

Answer 18

pain stimuli arising in one part of the body are perceived as coming from another part

Question 19

Sensory Cranial Nerves

Answer 19

Olfactory I, Optic II, Vestibulocochlear VIII

Question 20

All 12 Cranial Nerves

Answer 20

Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, & Hypoglossal

Question 21

Important nerves of the brachial plexus & upper limb

Answer 21

Axillary, Musculocutaneous, Median, Ulnar, Radial

Question 21

Flowchart of relationships within brachial plexus

Answer 21

Roots, Upper middle & lower Trunks, Anterior & posterior divisions, Lateral medial & posterior Cords, & Major terminal branches order (peripheral nerves

Question 22

Axillary Nerve

Answer 22

innervated the deltoid & teres minor muscles & the skin & joint capsule of the shoulder

Question 23

Musculocutaneous nerve

Answer 23

supplying motor fibers to the biceps, & coracobrachialis muscles

Question 24

Median Nerve

Answer 24

median nerve activates muscles that pronate the forearm, flex the hand & fingers, & oppose the thumb

Question 25

Ulnar nerve

Answer 25

supplies the flexor carpi ulnaris & the medial part of the flexor digitorum. innervates most intrinsic hand muscles & skin of the medial aspect of the hand

Question 26

radial

Answer 26

posterior arm skin & all extensor muscles of upper limb

Question 27

Dermatone

Answer 27

is an area of the skin innervated by the cutaneous branches of a single spinal nerve

Question 28

inborn (intrinsic) reflex

Answer 28

a rapid, predictable motor response to a stimulus. Unlearned, unpremeditated and involuntary

Question 29

Learned (acquired) reflexes

Answer 29

from practice or repetition

Question 30

types of reflexes

Answer 30

Somatic reflexes - activate skeletal muscle Autonomic (visceral) reflexes - activate visceral effectors (smooth or cardiac muscle or glands)

Question 31

Stretch and tendon reflexes

Answer 31

to smoothly coordinate s.m.

Question 32

Two types of information about the current state of a muscle are required for stretch & tendon reflexes

Answer 32

The length of the muscle (comes from muscle spindles in skeletal muscles) The amount of tension in the muscle and associated tendons (tendon organs provide

Question 33

Reciprocal inhibition

Answer 33

Branches of afferent fibers also synapse w/ interneurons that inhibit motor neurons controlling antagonistic muscles Consequently, the stretch stimulus causes the antagonists to relax so that they cannot resist the shortening of the stretched muscle caused by the main reflex arc.

Question 34

Importance of Stretch reflexes

Answer 34

monosynaptic & ipsilateral proves that sensory & motor connections are intact degree of excitability of the spinal cord can be measured

Question 35

Tendon Reflexes

Answer 35

Polysynaptic reflexes help to prevent damage due to excessive stretch Muscles relax & lengthen in response to tension

Question 36

Flexor (withdrawal) reflex

Answer 36

Initiated by a painful stimulus Causes automatic withdrawal of the threatened body part

Question 37

Crossed extensor reflex

Answer 37

accompanies the flexor reflex in weight-bearing limbs maintain balance stim side is withdrawn contralateral side is extended

Question 38

Superficial reflexes

Answer 38

elicited by gentle cutaneous stimulation Depend on upper motor pathways & cord-level reflex arcs Abdominal & Plantar reflexes