General Senses and Pain (2)

Question 1

Sensory Receptors definition

Answer 1

any structure specialized to detect a stimulus

Question 2

What are the two types of sensory receptors?

Answer 2

1. Simple: bare nerve endings
2. Complex: sense organ-structure composed of nervous tissue and other tissue types (enhance responses to specific stimuli)

Question 3

What is the purpose of sensory receptors?

Answer 3

transduction

Question 4

Transduction definition

Answer 4

conversion of one form of energy to another

conversion of stimulus energy into nerve signals

Question 5

Receptor Potential definition

Answer 5

small local electrical change on a receptor cell (neuron/ epithelial cell) brought about by a stimulus

Question 6

strong stimuli = ___ ___

Answer 6

action potential

release neurotransmitter = generates nerve signal to CNS

Question 7

Sensation definition

Answer 7

awareness of a stimulus

majority is filtered

Question 8

What are the four kinds of information that transmit through receptors?

Answer 8

1. Modality (type)
2. Location
3. Intensity
4. Duration

Question 9

What is Modality (type)?

Answer 9

hearing, taste, vision

determined by where sensory signals end in brain

Question 10

What is Location?

Answer 10

which nerve fibers are sending signals

receptive field- area within which a sensory neuron detects stimuli

Question 11

What is Intensity?

Answer 11

encoded in three ways:

1. how fast are neurons firing
2. number of neurons firing
3. which neurons are firing

Question 12

What is Duration?

Answer 12

how long stimulus lasts

changes in firing frequency over time

Question 13

Phasic Receptors definition

Answer 13

adapt rapidly: generate bursts of action potentials when first stimulated

Question 14

Tonic Receptors definition

Answer 14

adapt slowly: generate nerve signals more steadily throughout presence of stimulus

Question 15

What are the 5 classifications of receptors by modality?

Answer 15

1. Mechanoreceptors
2. Thermoreceptors
3. Pain Receptors
4. Chemoreceptors
5. Photoreceptors

Question 16

What are Mechanoreceptors?

Answer 16

stimulated by changes in pressure or body movement

prioreceptors- specialized stretch receptors in muscle

Question 17

What are Thermoreceptors?

Answer 17

stimulated by changed in the external or internal temperature
(primarily in the skin)

Question 18

What are Pain Receptors?

Answer 18

stimulated by damage or oxygen deprivation to the tissues

skin- respond to chemicals released by injured tissue

Question 19

What are Chemoreceptors?

Answer 19

Stimulated by changes in the chemical concentrations of substances
tastes buds/ olfactory receptors)

Question 20

What are Photoreceptors?

Answer 20

stimulated by light energy

only in eye

Question 21

What are the two ways receptors are classified?

Answer 21

1. Origin of stimuli

2. Distribution

Question 22

What are Exteroceptors?

Answer 22

detect external stimuli

vision, hearing, taste, touch, smell, temperature, pain

Question 23

What are Interoceptors?

Answer 23

detect internal stimuli

hunger, stretch receptors, pressure receptors, visceral pain, nausea

Question 24

What are Proprioceptors?

Answer 24

sense body position/movement

muscles tendons, joints

Question 25

General (somatosensory) senses are ___ distributed

Answer 25

widely

Question 26

Special sense are limited to ___

Answer 26

head | vision, hearing, taste, smell, equilibrium

Question 27

What are the special senses?

Answer 27

1. vision 2. hearing 3. taste 4. smell 5. equilibrium

Question 28

Free nerve ending are for ___ and ____

Answer 28

pain (nociceptors) | temperature (warm/ cold receptors)

Question 29

Bare dendrites have no ___ ____

Answer 29

special associates

Question 30

Skin and mucous membrane branch between ___

Answer 30

cells

Question 31

Somatosensory Projection Pathways definition

Answer 31

transmission of info from receptors to final destination in brain

Question 32

Most somatosensory signals travel by way of three neuron. What are they?

Answer 32

1. First order neurons 2. Second order neurons 3. Third order neurons

Question 33

Pain definition

Answer 33

Discomfort caused by tissue injury or noxious stimulation | results in evasive action

Question 34

Nociceptors definition

Answer 34

specialized nerve fibers

Question 35

What are the two types of nociceptors?

Answer 35

1. First (fast) Pain: myelinated fibers at 12 to 30 m/s (sharp, sudden, instantaneous- localized stabbing pain) 2. Slow (second) Pain: unmyelinated fibers at 0.5 to 2 m/s (long lasting, dull, continuous)

Question 36

What is nociceptive pain?

Answer 36

- superficial somatic pain (skin) - deep somatic pain (bones, muscles, joints) - visceral pain (organs)

Question 37

Neuropathic Pain definition

Answer 37

nerves, spinal cord, meninges or brain | --stabbing, burning, or tingling

Question 38

Injured tissues release chemicals that ____ pain fibers

Answer 38

stimulate

Question 39

What are the three ascending tracts of the projection pathways for pain

Answer 39

- spinothalamic tract - spinoreticular tract - gracile fasciculus

Question 40

What is the spinothalamic tract?

Answer 40

most significant pain pathway (Carries most somatic pain signals) (cerebral cortex)

Question 41

What is the spin-reticular tract?

Answer 41

activated visceral, emotional, and behavioral reactions to pain (limbic system, hypothalamus)

Question 42

What is the gracile fasciculus?

Answer 42

carries signals for visceral pain (stomach ache, kidney stones) (thalamus)

Question 43

Referred Pain definition

Answer 43

pain in viscera often mistakenly thought to come from the skin or other superficial site

Question 44

What are endogenous opioids?

Answer 44

"internally produced opium-like substances"

Question 45

Enkephalins definition

Answer 45

two analgesic oligopeptides with 200x potency of morphine

Question 46

Endorphins definition

Answer 46

larger analgesic neuropeptides

Question 47

Spinal Gating definition

Answer 47

stops pain signals in spinal cord (posterior horn)

Question 48

Facts of descending analgesic fibers

Answer 48

- arise in brainstem - descend in a spinal cord (reticulospinal tract) - block pain signals from traveling up spinal cord