The senses

Question 1

what is a sensation

Answer 1

conscious and subconscious awareness of change in the internal and external environment

Question 2

Perception

Answer 2

conscious awareness and interpretation of sensations.

- primary function of the cerebral cortex

Question 3

4 elements for sensation

Answer 3

1. stimulation of sensory receptor
2. Trabsduction of the stimulus (change in membrane potential)
3. Generation of nerve impulses
4. Integration of sensory input

Question 4

Sensory receptors - free nerve endings

Answer 4

bare dendrites, lack any obvious structural specialisation

Question 5

encapsulated nerve endings

Answer 5

dendrites enclosed

Question 6

separate cells

Answer 6

receptors for taste, olfaction, vision and hearing

Question 7

exteroreceptors

Answer 7

• located at the external surface of the body
• ## respond to stimuli that originate from outside the body

Question 8

Interoreceptors

Answer 8

• located in blood vessels, muscles and in the nervous system
• monitor the internal environment

Question 9

Proprioreceptors

Answer 9

• located in the muscles, tendons and joints

- provide info. about body position, muscle length and tension

Question 10

mechanoreceptors

Answer 10

• respond to mechanical stimulation such as stretching or bending of cells

Question 11

thermoreceptors

Answer 11

• respond to changes in temperature

Question 12

Nocioreceptors

Answer 12

• respond to painful stimuli in the mouth, nose and body fluid

Question 13

photoreceptors

Answer 13

respond to light

Question 14

chemoreceptors

Answer 14

respond to chemicals in the mouth, nose and bodily fluids

Question 15

osmoreceptors

Answer 15

respond to changes in the osmotic pressure of body fluids

Question 16

Adaptation

Answer 16

where the response produced by the sensory receptor (e.g. the graded potential) becomes smaller when the stimulus is presented over a prolonged, sustained period. Thus, the number of action potential reduces.

Question 17

somatic sensations

Answer 17

sensations that arise from receptors

- skin, mucous membranes, muscles, tendons, joints

Question 18

Tactile sensations

Answer 18

touch 
pressure
vibration
itch
tickle 
by mechanical stimuli

Question 19

receptors in the skin responding to touch

Answer 19

corpuscle of touch
hair root plexuses
type 1 and 2 cutaneous mechanoreceptors

Question 20

receptors that respond to pressure

Answer 20

• corsucle of tuch
• type 1 cutaneous mechanoreceptors
  lamellated corpsucles

Question 21

receptors that respond to vibration

Answer 21

corpsucle of touch

Lamellated corpsucle

Question 22

respond to itch and tickles

Answer 22

• free nerve endings

- for itch, the free nerve endings respnds to chemicals released during inflammatory response

Question 23

respond to thermal sensation?

Answer 23

thermoreceptors

Question 24

painful stimuli ?

Answer 24

nocioreceptors

Question 25

2 types of pain

Answer 25

slow pain - pain begins seconds after stimulus and gradually increases in intensity over the course of seconds to minutes e.g. burning, throbbing. Fast pain - acute, sharp. pain occurs rapidly after stimulus.

Question 26

superficial somatic pain

Answer 26

pain that arises from stimulation of nocioreceptors in the skin

Question 27

deep somatic pain

Answer 27

pain that arises from stimulation of nocioreceptors in skeletal muscle joints/tendons

Question 28

Visceral pain

Answer 28

pain that arises from the stimulation of nocioreceptors present in visceral organs

Question 29

function of propriorecptors

Answer 29

enable us to determine the location of our body in space | - found in muscles and tendons and degree of stretch and contraction.

Question 30

Proprioreceptors in muscles ?

Answer 30

- muscle spindles | monitor changes in length of skeletal muscles and stretch reflexes

Question 31

proprioreceptors in tendons

Answer 31

tendon organs | provide information related to muscle tension

Question 32

Proprioreceptors in joints

Answer 32

Joint kinaesthetic receptors - sense joint position and movement - respond to joint pressure, and the acceleration and deceleration of joints during movements

Question 33

What type of stimuli respond to taste and small

Answer 33

chemical senses Due to interactions of oderants and tastants involves 3 types of cells

Question 34

olfactory cells

Answer 34

- bipolar cells (one dendrite + one axons) - involves the olfactory bulb - by the axon - olfactory epithelium - where oderants are detected

Question 35

supporting cell

Answer 35

epithelial cells of mucous membrane ling the nose | - provide physical support, nutrients and electrical insulation for olfactory cells

Question 36

basal stem cells

Answer 36

continually undergoes cell division | responsible for the continued production of new olfactory receptor cells

Question 37

Olfactory glands

Answer 37

- produce mucous that is secreted onto the olfactory epithelium - the mucus moistens the epithelium and dissolves oderants

Question 38

effect of an oderant binding to an olfactory receptor

Answer 38

- leads to generation of a depolarising graded potential | - if the depolarisation is large enough, action potentials are generated and nerve impulses are sent to CNS

Question 39

Role of olfactory nerve

Answer 39

- pathway of olfactory information to the CNS. - the axons in the olfactory nerves terminate in the frontal lobes. - axons travelling in the olfactory tract project to the primary olfactory area of the cerebral cortex. Others goes to hypothalamus involved in memories and emotion

Question 40

5 primary tastes

Answer 40

- bitter - sour - salty - sweet - msg

Question 41

receptors of taste

Answer 41

- supporting cells = surround the gustatory cells and provide support - gustatory receptor cells - responsible for detecting chemicals. - basal cells - stem cells that provide supporting cells

Question 42

effect of the binding of a tastant (chemical dissolved in saliva) to a taste receptor ?

Answer 42

- generation of depolarising graded potentials and the release of transmitter = stimulates sensory neurons that project to the CNS

Question 43

Pathway of gustatory information to the CNS ?

Answer 43

1. 3 cranial nerves = vagus, glassopharyngeal nerve and facial nerve. 2. medulla oblongata 3. hypothalamus and thalamus 4. cortex