Senses

Question 1

What is the sensation associated with touch?

Answer 1

Somatosensation

Question 2

What is sensation?

Answer 2

The registration of physical stimuli from the environment by the sensory organs

Question 3

What is perception?

Answer 3

The interpretation of sensations by the brain

Question 4

Why do sound waves not necessarily equal sound?

Answer 4

Our version of reality is our perception of the sensory world
- Not sound unless our brain perceives it

Question 5

What does nocioception relate to?

Answer 5

Pain and temperature

Question 6

What does proprioception relate to?

Answer 6

Body awareness

Question 7

How does nocioception happen?

Answer 7

Damage to the dendrite or to surrounding cells releases chemicals that stimulate the dendrite to produce AP’s

Question 8

How does hapsis (touch) happen?

Answer 8

Pressure on the various types of tissue capsules mechanically stimulates the dendrites within them to produce AP’s

Question 9

How does proprioception happen?

Answer 9

Movements stretch the receptors to mechanically stimulate the dendrites within them to produce AP’s

Question 10

What do the free nerve endings for pain tell you about?

Answer 10

Sharp and dull pain

Question 11

What do the free nerve endings for temperature tell you about?

Answer 11

Heat or coldness

Question 12

What does Meissner’s corpuscle tell you about?

Answer 12

Touch

Question 13

What does Pacinian’s corpuscle tell you about?

Answer 13

Flutter

Question 14

What does Ruffini corpuscle tell you about?

Answer 14

Vibration

Question 15

What does Merkel’s receptor tell you about?

Answer 15

Steady skin indentation

Question 16

What do hair receptors tell you about?

Answer 16

Flutter or steady skin indentation

Question 17

What do muscle spindles tell you about?

Answer 17

Muscle stretch

Question 18

What do Golgi tendon organs tell you about?

Answer 18

Tendon stretch

Question 19

What do joint receptors tell you about?

Answer 19

Joint movement

Question 20

What is the function of the specialised dendrites in the sensory receptors?

Answer 20

They will open ion channels if stimulated by the appropriate external stimulus

Question 21

What happens when a feather rubs a hair on the skin?

Answer 21

• The dendrite of a touch receptor is stretched when the hair moves
• Causes stretch-sensitive channels on dendrite to open, allowing Na+ influx
• This Na+ influx causes voltage-sensitive Na+ and K+ channels to open, producing a nerve impulse

Question 22

What happens when photoreceptors absorb light?

Answer 22

• Causes a change in the shape of light sensitive pigments

- Ultimately result in ion channels opening

Question 23

What do dorsal-root ganglion neurons respond to?

Answer 23

• Fine touch and pressure
• Joint/tendon/muscle change
• Pain and temperature

Question 24

What is the medial lemniscus?

Answer 24

The pathway that the ventral spinothalamic tract joins to

Question 25

What does the ventral spinothalamic tract recieve input from?

Answer 25

Pain and temperature neurons

Question 26

What does the dorsal-column nuclei relay?

Answer 26

Fine touch and pressure sensations

Question 27

What does the medial lemniscus contain?

Answer 27

Axons that carry sensory information to the ventrolateral thalamus

Question 28

What does the ventrolateral thalamus relay?

Answer 28

Sensory information to the somatosensory cortex

Question 29

What does unilateral damage to the spinal chord cause?

Answer 29

- Loss of fine-touch and pressure sensation on the same side of the body below the cut - Loss of pain and temperature sensation on the opposite side of the body below the cut

Question 30

What can our sense of somatic sensation be divided into?

Answer 30

1) Touch (mechanical stimulation) 2) Pain (heat, chemical, or mechanical stimulation) 3) Limb proprioception (muscle, joint stimulation)

Question 31

What type of axons carry pain?

Answer 31

Unmyelinated | - other somatosensory neurons are myelinated

Question 32

What is a receptive field?

Answer 32

Each sensory receptor is sensitive to physical stimuli that impinge on a circumscribed area of the body, and this area is known as the receptive field

Question 33

What is the receptive field of a touch (somatosensory) neuron?

Answer 33

The portion of skin that stimulates the (dendritic) processes of receptor neuron

Question 34

Why is the size of the receptive field an important factor in determining sensitivity of a sensory system?

Answer 34

Receptor neurons with smaller receptive fields allow greater sensitivity

Question 35

How do sensory receptors indicate how strong a stimulus is?

Answer 35

No. Of AP’s they fire

Question 36

Where is vision processed?

Answer 36

Occipital/temporal/parietal

Question 37

Where is hearing processed?

Answer 37

Temporal

Question 38

Where is touch processed?

Answer 38

Parietal

Question 39

Where is taste processed?

Answer 39

Frontal

Question 40

How are sensory pathways from periphery to the cerebral cortex organised?

Answer 40

To preserve the spatial relations of adjacent receptors in the body

Question 41

Why do some parts of the body have more cortical space than others?

Answer 41

There are more receptors in the hands and face than in other areas of the brain

Question 42

In olfaction, what are changes in the membrane potential meditated by?

Answer 42

Metabotropic ion channels

Question 43

During olfaction, what does scent interact with?

Answer 43

Chemical receptors

Question 44

During olfaction, what do chemicals dissolve in and interact with?

Answer 44

Mucosa and the cilia

Question 45

What allows perception of a particular smell?

Answer 45

Neurons respond to a range of odours, and summer activity over a range of neurons allows perception of a particular smell

Question 46

Where do smell signals go once they have entered the brain (unlike other senses)?

Answer 46

Bypass the thalamus and go directly to the amygdala and pyriform areas

Question 47

Where are odours entering one nostril processed?

Answer 47

The same side of the brain

Question 48

What does the limbic system give in response to odours?

Answer 48

Emotional response

Question 49

What does the orbitofrontal region give in response to odours?

Answer 49

Conscious perception of odours

Question 50

What are pheromones?

Answer 50

Chemicals that are not perceived consciously as smells, but do nevertheless influence behaviour - Chemical substance released into environment

Question 51

What are taste stimuli (tastants)?

Answer 51

Chemicals that are detected by taste receptors on the tongue

Question 52

What can damage to the frontal lobe of the right hemisphere lead to (in terms of taste)?

Answer 52

Gourmand syndrome | - Previously normal people into fanatical seekers of fine food

Question 53

How are taste receptors grouped?

Answer 53

Into taste buds with several receptor types

Question 54

What does the opening of ion channels on the microvilli lead to (taste)?

Answer 54

Membrane potential changes

Question 55

What cranial nerves form the main gustatory nerve, the solitary tract?

Answer 55

Facial, glossopharangeal, and vagus

Question 56

What does the solitary tract divide into?

Answer 56

2 pathways: 1) Sensation 2) Emotional/hormonal response

Question 57

What combines to give us flavour?

Answer 57

Taste and olfaction

Question 58

What does mastication do?

Answer 58

Unlocks odours from food and mixes them with air | - Holding your nose whilst eating inhibits flavour

Question 59

What 2 odours can the brain distinguish between?

Answer 59

Orthonasal and Retronasal

Question 60

What is one explanation for synesthesia?

Answer 60

Signals from receptors in one sensory system have diverted to the wrong part of the brain