Lecture 2

Question 1

receptors

Answer 1

stimulus energy to electric potentials can be transmitted and interpreted by the nervous system

Question 2

sensory neuron

Answer 2

pns pathway to cns

Question 3

mechanoreceptors-
photoreceptors-
chemoreceptors-
thermoreceptors -

Answer 3

mechanical energy
light nergy
chemical energy
thermal energy

Question 4

common to all sensory receptors

Answer 4

mechanisms by wich the stimulus energy leads to change in the electrochemicla state of the cell or axon

a mechanism to convert passive receptor potientials into an action potential

Question 5

how are receptor potentionals generated

Answer 5

gerenarated by the influx and efflux of ions

Question 6

how are action potentioan generated

Answer 6

generated by the influx efflux of ions and are kept alive bc they regenerate

Question 7

types of stimulus segregation by receoptors

Answer 7

• type
• duration, onnset, offset
• intensity
• location

Question 8

Stimulus modality stuff

Answer 8

somatosensory
vestibular
visual
auditory

Question 9

somatosensory

Answer 9

any mechanoreceptors or themoreceptros or nociceptors that are in skin, fatty tisue beneath the skin, muscle or muscle tissue

Question 10

Vestibular

Answer 10

mechanoreceptors in the otoliths/labrynths of the inner ear

Question 11

Visual

Answer 11

photoreceptors located in the retina

Question 12

auditory

Answer 12

mechanoreceptors located in the cochlea of the ear.

Question 13

fast adapting and slow adapting sensory responces

Answer 13

Fast adapting is vigorous but transient. responds to sudden changes in the stimulus energy

Slow addapting is measured but sustained and responds to a constant stimulus energy.

Question 14

how does photoreceptors work

Answer 14

absorb photons from visible light wavelenghths leading to a chemical reaction that generates the receptro potential

Question 15

pathway for photo receptors when light hits them

Answer 15

pigment absorbs light

Na+ gated ion chanels are cloosed

this decreases the receptor potential

this releases less nuerotransitters

Question 16

how does photoreceptors work with bipolar cells

Answer 16

they use bipolar cells to sned a clear stimulus to the ganglia wich is the sensory nerve. The smaller the receptor potential the stronger the stimulus energy

Question 17

the two types of photoreceptors

how much they represent

where they located

what they have

what colours they do

Answer 17

rods and conses

96 % rods 4% cones

Rods: along the border of the retina
Cones: in the middle of the retina

Rods: have rhodhopsin
Cones: have iodopsin

Rods: cyan/green
cones: there are three types each representing thier own waveleghnths

Question 18

what are hair cells and what do they mediate

Answer 18

mechanorepceptors that mediate audio and vestibular senses

embedded in the semicircular canals mediate out sense of angular head rotation

Question 19

The tonotopic map

Answer 19

generated by the differential composition of the basilar membrane as it winds around the cochlea

The locations of the specific axons generating action potentials represents a specific frequency of sound

Question 20

Semi circuluar canals that mediate sense of angular head rotation

Answer 20

Horizantal canal - Head yaw (head side to side)
Superior canal - Head pitch (nodding of the head)
Posterior canal - Head roll (moving the head to touch shoulder)

Question 21

Hair cells embedded in the otolith organs (mechanoreceptors: hair cells)

Answer 21

Hair cells embedded in the otolith organs mediate our perception of head translation and gravitational forces

Question 22

Otolith organs: Utricle (Hair cells)

Answer 22

responsible for horizantal acceleration of the head

Question 23

Otolith organs: Saccule (Hair cells)

Answer 23

responsible for the vertical acceleration of the head (relative to gravity)

Question 24

Mechanoreceptors: Cutaneous receptors

Answer 24

translate mechanical forces acting on the skin into receptor potential through mechanically gated ion channels

Question 25

What are the cutaneous mechanoreceptors

Answer 25

Meissner’s corpuscles Pacinian corpuscle Merkel disk receptor Ruffini ending (SA)

Question 26

Cutaneous mechanoreceptors : corpuscles

Answer 26

Na+ and Ca2+ ions channels on an exposed nerve ending are mechanically deformed as corpuscle is compressed

Question 27

Merkel disk and Ruffini endings

Answer 27

Na+ and Ca2+ ions channels on an exposed nerve ending are mechanically deformed as skin is stretched Mechanical deformation creates a pore for ions to flow through

Question 28

What are the superficial cutanous receptors (1)

Answer 28

Messner corpuscles (RA1) Merkel disk (SA1)

Question 29

what are the fast adapting cutaneous receptors (RA)

Answer 29

Meissner corpuscles (RA 1) Pacinian corpuscle (RA 2)

Question 29

What are the deep cutaneous receptors (2)

Answer 29

Pacinian corpuscle (RA2) Ruffini ending (SA2)

Question 30

What are the slow adapting (SA)

Answer 30

Merkel disk (SA1) Ruffini ending (SA2)

Question 31

Superficial cutaneous receptors

Answer 31

Have small receptive fields Are densely populated in areas of the skin used to explore objects

Question 32

Deep receptors

Answer 32

Have larger receptive fields Are best situated to detect vibrations in objects (shifting liquid inside a water bottle)k

Question 33

Mechanoreceptors: Proprioceptors

Answer 33

Proprioceptors translate mechanical forces generated by the body’s own position and movement Internal sense of body

Question 34

Proprioceptors: Golgi tendon organ

Answer 34

Tuned to sense muscle force

Question 35

Proprioceptors: muscle spindle fibers

Answer 35

Tuned to sense muscle length (sensitive to stretch)

Question 36

Proprioreceptors: Joint receptors

Answer 36

Tuned to sense (extreme) joint angles Protective against injury

Question 37

Orientation of spindle fibers (proprioceptors)

Answer 37

Spindle fibers (intradusal muscle fibers) are positioned parallel to standard skeletal muscles fibers (extrafusal muscle fibers) Lengthen and shorten as extrafusal fibers contract and relax

Question 38

What happens when muscle relaxation stretches the spindle fibers (proprioceptors)

Answer 38

tension on the spindle fiber surface pulls open the mechanically gated ion channels influx of ions generates a receptor potential

Question 39

What happens when muscle contraction releases stretch tension

Answer 39

mechanically gated ion channels fold in on themselves Ions channels become less permeable, decreasing the receptor potential

Question 40

What are the two classes of spindle fibers (proprioceptors)

Answer 40

Dynamic Group Activity is a function of both muscle length and rate of change in muscle length Static Group Activity is a function of muscle length

Question 41

Where are the Golgi Tendon Organs and how do they work???

Answer 41

located in series between the muscle fibers and the muscle tendon Forces generated by the mucles and transmitted to the bone (via the tendon) must act on the GTO

Question 42

Mechanoreceptors: Nociceptive receptors

Answer 42

Nociceptive mechanoreceptors translate mechanical, chemical and thermal forces from damaged tissue or the threat of damage to tissue bare nerve endings

Question 44

Nociceptors are senstivie to..

Answer 44

Thermal - activated by extreme temperatures Mechanical - activated by intense pressure on the skin Chemical - activated by internal or external toxins Polymodal - activated by chemical, thermal or mechanical stimuli