Body Senses

Question 0

Tactile receptors

Answer 0

Meissners corpuscles
Merkels disks
Ruffini’s corpuscles
Pacinian corpuscles

Question 1

Somatosensory system (3)

Answer 1

1 touch

2. Proprioception = position of body parts
3. Kinesthesis = movement of body parts

Question 2

Where are the tactile receptors in layers of skin

Answer 2

Meissners corpuscles EDIPERMIS
Merkels disks EDIPERMIS
Ruffini’s corpuscles DERMIS
Pacinian corpuscles SUBCUTIS

Question 3

Superficial tactile receptors

Answer 3

Meissner/merkel

Respond best to LIGHT TOUCH

Question 4

Deep tactile receptors

Answer 4

Pacinian/ruffini

Respond best to PRESSURE and STRETCH

Question 5

Thermoreceptors (free nerve endings)

Answer 5

WARMTH FIBRES
Signal an increase in skin temp
COLD FIBRES
Signal decrease in skin temp

Question 6

Proprioception/kinaesthesia receptors

3

Answer 6

Muscle spindles
Golgi tendon organs (muscle tension/in tendon)
Joint receptors

Question 7

Slower somatosensory pathway

Answer 7

SPINOTHALAMIC PATHWAY

carries slow temperature signals from free nerve endings

Question 8

Faster somatosensory pathway

Answer 8

LEMNISCAL PATHWAY

Carries fast signals from mechanoreceptors (touch, proprioception)

Question 9

Both pathways have branching circuits in ________ for ______

Answer 9

Spinal cord

Reflex responses

Question 10

Somatotropin organisation

Answer 10

Bits next to eachother on the body are represented next to each other in the cortex.

Question 11

Somatosensory homunculus

Answer 11

Illustrates somatotopic organisation and corticalagnification

Question 12

What has a small receptive field

Answer 12

Mouth/fingers

Think foveal vision, more densely packed

Question 13

Variation in acuity with body location mirrors…..

Answer 13

Cortical magnification

Question 14

vestibular system?

Answer 14

signals head’s acceleration and altitude relative to gravitational verticle

Question 15

what makes up the vestibular labryinth?

Answer 15

3 semicircular canals: posterioir, anterioir & lateral
2 otolith organs: utricle & saccule

2 vestibular labrynths

Question 16

the body can move linearly accross 3 possible axes.

these are…

Answer 16

z (frontal, roll rotation)
y (median, pitch)
x (transverse, yaw)

Question 17

how many degrees of freedom? possible ways the body can move

Answer 17

6 completely independent of others

Question 18

vestibular transduction

Answer 18

head acceleration of static tilts causes minute displacements if hair cells (stereocillia towards kinocillium) that activates sensory nerves

Question 19

capula

Answer 19

bundle of hair cells in each semicircular canal

Question 20

macula

Answer 20

patch of hair cells in both the utricle and saccule

Question 21

what part of vesitbular labrynth deals with which axes

Answer 21

utricle & saccule = x (linear acceleration), y (static tilt)

semicircular canals = z (rotational acceleration)

Question 22

vestibular system cant tell the difference between which 2 axes and why

Answer 22

linear acceleration and static stilt/ x and y

because they are equivalent stimuli. each respond to motion in various directions along the flat plane of the otolithic membrane

Question 23

kinocillium

Answer 23

a single tall hair in the hair cell

Question 24

stereocillia

Answer 24

the smaller hairs in a hair cell

Question 25

vestibular hierarchy what happens from sensory nerve fibres...

Answer 25

sensory nerve fibres from the hair cells project to the vestibular nuclei of the brainstem, then go 4 ways 1. VESTIBULO- CEREBELLAR; posture, movement 2. VESTIBULO-THALAMIC; balance 3. VESTIBULO-SPINAL; limb movements 4. VESTIBULO-OCULAR; eye movements

Question 26

oculogyral illusion

Answer 26

spin around, stop, feel like your going other way. explanation....... due to inertia, fluid in the semicircular canals decelerates more slowly than the canals when spin stops

Question 27

oculogravic illusion

Answer 27

when body undergoes linear acceleration, an illusory impression of body tilt occurs (think plane take off)

Question 28

Where are the cell bodies of mechanoreceptors

Answer 28

In the dorsal root ganglia just outside the spinal column. Their peripheral axons end below the surface of the skin, and their central axons project towards the brain

Question 29

haptic perception

Answer 29

touch + kinesthesis

Question 30

myelinated neurons are?

Answer 30

in the lemniscal pathway

Question 31

where is the primary somatosensory cortex

Answer 31

thin strip running over the top of the head, ear to ear | cells near left ear have rfs near right side of the mouth and face

Question 32

vertical oriented groups in the cortex?

Answer 32

yes horizontally and vertically organised. | vertical for cortical cells that connect to the same type of somatosensory receptor in the same region of the body

Question 33

hair cells and axons and action potentials

Answer 33

hair cells have no axons or action potentials

Question 34

when is inertia evident

Answer 34

only evident during acceleration or deceleration. once a constant velocity is reached all fluids/membranes travel at the same speed, and there is no basis for hair cell deflection

Question 35

how many dif types of receptors in the somatosensory system

Answer 35

8