Neuro Ch 9 Sensory Pathways

Front 1

Sensory Receptors

Back 1

cells that detect various stimuli and produce receptor potentials

Front 2

How are receptors classified

Back 2

by the form of stimulus energy that is most effective at the receptor surface

Front 3

Chemoreceptors

Back 3

respond to biochemical stimuli such as, smell, taste, internal pH, and metabolites, changes in blood chemistry

Front 4

Photoreceptors

Back 4

-respond to light
-rods and comes in retina

Front 5

Thermoreceptors

Back 5

-respond to temperature
-usually at free nerve endings in the skin

Front 6

mecahnoreceptors

Back 6

-respond to physical deformation
-Touch, pressure, vibration, muscle length and tension, auditory and vestibular receptors

Front 7

Nocioreceptors

Back 7

-respond to pain
-examples include: extreme heat or cold, excessive pressure or inflammatory chemicals

Front 8

Sensory transduction

Back 8

the process by which sensory receptor cells convert stimulus energy into an electrical signal

Front 9

Receptor potential

Back 9

-local, graded potentials
-may be depolarizing or hyper polarizing
-can be direct ion channels or G-protein channels

Front 10

Adaptation

Back 10

-become less sensitive to stimuli over time; there is decreased receptor potential overtime

Front 11

slow adapting

Back 11

better for sustained stimulus

Front 12

rapid adapting

Back 12

better for changing stimulus or sensing the beginning and end of stimulus

Front 13

All ______ receptors produce receptor _____________.

Back 13

1. sensory
2. potentials
-includes Photoreceptors, auditory, vestibular receptors

Front 14

How do sensory receptors produce receptor potentials?

Back 14

local potential spreads passively to the synapse -->postsynaptic potential -->trigger zone --> change AP frequency

Front 15

What types of sensory receptors can produce action potentials?

Back 15

- those that must convey information over long distances
-Receptor is capable of propagating an AP (AP freq. is modulated by receptor potential)
-there is no peripheral synapse
-trigger zone is part of the same neuron that contains receptor ending

Front 16

Somatosensory receptors

Back 16

-aka skin
-includes many different types of receptors with specific stimuli, eg touch, temperature, vibration
-all are pseudounipolar neurons with central process that terminate in the CNS and peripheral receptive endings

Front 17

Encapsulated somatosensory receptors

Back 17

-meissner's corpuscle
-pacinian corpuscle
-ruffinni ending

Front 18

meissner's corpuscle

Back 18

-rapid adaptation
-fine touch

Front 19

pacinian corpuscle

Back 19

-rapid adaptation
-vibration

Front 20

ruffinni ending

Back 20

-slow adaptation
-pressure

Front 21

Non-encapsulated somatosensory receptors

Back 21

-hair follicle receptor
-merkel ending
-free nerve ending
-nocioceptor

Front 22

hair follicle receptor

Back 22

- movement/touch
-rapid adaptation, quick touch

Front 23

merkel ending

Back 23

-slow adaptation
-sustained touch

Front 24

free nerve ending

Back 24

-pain/touch
-some are mechanoreceptors
-temperature receptors

Front 25

nocioceptor

Back 25

-respond to intense mechanical stimuli (such as pinching), extreme temperature, chemicals
-fast pain
-slow pain

Front 26

fast pain

Back 26

-delta pain
-fast, sharp, well localized pain (mylinated)

Front 27

slow pain

Back 27

slow, dull, aching, longer-lasting pain - (unmyelinated)

Front 28

Muscle Spindle

Back 28

- a few fibers within a muscle spindle that are responsive to stretch, limb position and movement
-Contributes MOST to kinesthesia (the conscious awareness of movement)
-alpha motor neurons & gamma motor neurons; these are coactivated

Front 29

primary endings muscle spindle

Back 29

-respond to onset of stretch
-rapidly adapt

Front 30

secondary endings muscle spindle

Back 30

-respond to sustained stretch
-slowly adapt

Front 31

Alpha motor neurons

Back 31

-source of motor innervation to extrafusal muscle – for contraction

Front 32

Gamma motor neurons

Back 32

source of motor innervation to(intrafusal) muscle spindle – for sensitivity maintenance in contracted muscle

Front 33

Golgi Tendon Organ

Back 33

-spindle shaped receptor an musculotendinous junction
-tell the brain the amt of tension in muscles and tendons
-Contributes MOST to the sense of force exerted during movement

Front 34

Joint Receptors

Back 34

-similar to those found in skin and muscle
-Free nerve endings, golgi tendon organs, and pacinian corpuscles

Front 35

Mechanoreceptors of hollow organs (aorta)

Back 35

-visceral receptor
– monitor blood pressure/volume

Front 36

Chemoreceptors (carotid body/sinus)

Back 36

-visceral receptor
– monitor blood gases and pH

Front 37

Nociceptors (organ capsule)

Back 37

-visceral receptor
– monitor distention

Front 38

Endoneurium

Back 38

-connective tissue covering of a nerve
- loose connective tissue that encloses axons and their myelin sheaths

Front 39

Perineurium

Back 39

-connective tissue covering of a nerve
- coarse connective tissue that bundles fibers into fascicles

Front 40

Epineurium

Back 40

-connective tissue covering of a nerve
-tough fibrous sheath around a nerve

Front 41

A fibers

Back 41

- myelinated sensory and motor fibers
-subdivided into alpha and delta fibers

Front 42

A alpha fiber

Back 42

largest and most rapidly conducting

Front 43

A delta fiber

Back 43

smallest and slowest of group A

Front 44

B fibers

Back 44

-myelinated visceral fibers
-(preganglionic autonomic and afferents)

Front 45

C fibers

Back 45

unmylinated

Front 46

2nd classification system of nerve fiber diameter is based on what?

Back 46

direct measurements of axonal diameter

Front 47

What are the 2nd classifications of nerve fiber diameter?

Back 47

-I, II, III are larger number = smaller size
-IV are unmyelinated