Proprioception, Interoception And Temperature Sensation

Question 1

What is proprioception?

Answer 1

Proprioception is the sense though which we perceive the position and movement of our body, including our sense of equilibrium and balance, senses that depend on the notion of force
- Proprioceptive senses, particularly of limb position and movement, deteriorate with age and are associated with an increased risk of falls in the elderly

Question 2

Name kinesthetic receptors?

Answer 2

Muscle spindles
Golgi tendon organs
Joint receptors
Skin receptors

Question 3

Name the endings of joint receptors?

Answer 3

Joint receptors include several types of encapsulated endings
1. Ruffini endings
2. tendon organ-like endings
3. Pacinian corpuscle
4. smaller paciniform endings

Question 4

What are the 4 classes of mechanoreceptors in the skin?

Answer 4

1. Meissner’s corpuscles (fast-adapting type I, FAI)
2. Pacinian corpuscles (fast-adapting type II, FAII)
3. Merkel’s disks (slowly adapting type I, SAI)
4. Ruffini endings (slowly adapting type II, SAIl).

Question 5

State the location and function of the Meissners corpuscles?

Answer 5

1. Location
   Found in the upper dermis but project into the epidermis.
2. Skin type
   Primarily in the glabrous (non-hairy) skin and are particularly abundant in the fingertips, lips, and other areas of the skin where one’s ability to discern spatial location of touch sensations is highly developed
3. Function
   Respond to fine touch pressure, low-frequency vibration or flutter

Question 6

State the location and function of the Pacinian corpuscles?

Answer 6

1. Location
   - Lie deep in the dermis and can be as long as 2 mm and almost 1 mm in diameter
   - Found throughout the whole body but the highest densities are in the fingers
2. Function
   - Sense vibration and deep pressure

Question 7

State the location and function of the Merkels discs?

Answer 7

1. Function
   Respond to touch
2. Location
   Found in the upper layers of skin near the base of the epidermis, both in hairy and glabrous skin
   Densely distributed in the fingertips and lips

Question 8

State the location and function of Ruffini endings?

Answer 8

1. Location
   Found in both glabrous and hairy skin
2. Function
   Detect skin stretch, deformations within joints, and warmth
   Note: that these warmth detectors are situated deeper in the skin than are the cold detectors.

Question 9

What are the pathways of proprioception?

Answer 9

1. Conscious
2. Unconscious

Question 10

Describe the pathway of conscious proprioception?

Answer 10

travels in the DCML
- deals with aspects such as judging the weight of an object or where a person’s limbs are in space

Question 11

Describe the pathway for unconscious proprioceotion?

Answer 11

travels in the spinocerebellar tract and serves as an important backup to conscious proprioception
- involved in the acquisition and maintenance of complex, skilled movements such as walking, talking and writing.

Question 12

What is interoception?

Answer 12

Interoception is the perception of sensations from inside the body
E.g. heart beat, respiration, satiety, as well as the ANS activity related to emotions

Question 13

Interoception encompasses?

Answer 13

(1) the afferent (body-to-brain) signalling through distinct neural and humoral (including immune and endocrine) channels
(2) the neural encoding, representation, and integration of this information concerning internal bodily state
(3) the influence of such information on other perceptions, cognitions, and behaviours
(4) and the psychological expression of these representations as consciously accessible physical sensations and feeling

Question 14

Function of interoception?

Answer 14

Helps maintain homeostasis and interpret physical sensations to guide health-related behaviour

Question 15

Name interoceptive homeostatic emotions?

Answer 15

Hunger
Fullnes
Thirst
Sensory overload
Pain
Illness
Body temperature
Physical exertion
Sleepiness
Need for the bathroom

Question 16

Name interoceptive affective emotions?

Answer 16

Excitement
Distraction
Joy
Frustration
Calmness
Fear
Safety
Sadness
Love
Focus
Anxiety
Boredom
Energized

Question 17

Importance of interoceptive awareness?

Answer 17

• Helps us self-regulate
• One is able to identify and manage how one feels

Question 18

What contributes to our perception of temperature?

Answer 18

Thermoreceptors in the skin
Note: temperature sensitivity is not spread uniformly across the skin

Question 19

How do different regions of skin show distinctly different sensitivities to temperature?

Answer 19

• There are six distinct transient receptor potential (TRP) channels in thermoreceptors that confer different temperature sensitivities
• As a rule, each thermoreceptive neuron appears to express only a single type of channel

Question 20

Compare the difference in numbers between cold and warm receptors?

Answer 20

Cold receptors outnumber warm receptors by a ratio of 4:1

Question 21

What is the adaptation zone for both warm and cold sensations?

Answer 21

For both cold and warm sensations, the range of temperatures between 29 and 37 °C is an adaptation zone
- Application of an experimental stimulus or natural object within the adaptation zone to skin or mucosa is initially felt as warm or cold, but becomes neutral within minutes

Question 22

What temperatures are considered painful?

Answer 22

Temperatures above 45 °C
and below 15 °C
Note: that temperatures above
50 °C and below 0 °C can cause significant tissue damage.

Question 23

Describe the thermoreception pathways?

Answer 23

• Carried in the lateral spinothalamic tract
• “Pa-Te-La” (Pain, Temperature via Lateral
•spinothalamic).
• Any stimulus that is too intense can be perceived as pain because temperature sensations are conducted along the same pathways that carry pain sensations