L8 - Somatosensory Systems and Chemoreception

Question 1

What components make up sensory systems? (3)

Answer 1

1) Sensory receptors
2) Neural pathways that conduct information to the brain
3) Processing areas in the brain (higher centres)

Question 2

Not all sensory information reaches consciousness. What is the term for when sensory information is taken to higher centres but is not yet processed?

Answer 2

Sensation

Question 3

What is the term for when sensory information from a stimulus is taken to the higher centres and processed to give meaning?

Answer 3

Perception

Question 4

What are examples of senses that are normally processed consciously?

Answer 4

Vision, Hearing, touch, temperature, pain, itch, proprioception etc.

Question 5

What are examples of senses that are normally processed subconsciously?

Answer 5

BP
Muscle length and tension
Blood glucose concentrations
Lung Inflations etc.

Question 6

What are the three components of the sensory system where stimuli get processed into formats that the nervous system can understand?

Answer 6

1) Tissues/Cells that surround the nerve/sensory cell
2) Receptor membrane of the sensory cell
3) Membrane of the sensory nerve fibre

Question 7

At which component of the sensory system does the stimulus get modified?

Answer 7

1st component - tissues/cells surrounding the sensory cell

Question 8

At which component of the sensory system does the modified stimulus get further transduced/amplified?

Answer 8

2nd component - receptor systems on the neuron membrane

Question 9

At which component of the sensory system does the transduced signal become coded by graded receptor potential?

Answer 9

3rd component - The membranes of the sensory nerve fibre.

Question 10

What are cortical areas?

Answer 10

Regions in the brain that are involved in understanding sensory information

Question 11

Where are cortical regions found?

Answer 11

In the different lobes of the brain.

Question 12

What are the 4 lobes of the brain?

Answer 12

Frontal Lobe
Parietal Lobe
Occipital Lobe
Temporal Lobe

Question 13

Which cortex is involved in the conscious experience of sensory input perception?

Answer 13

Cerebral Cortex

Question 14

What is an association cortex?

Answer 14

Cortical areas that lie outside the primary cortical sensory areas
- secondary cortexes, tertiary cortexes

Question 15

What is the role of an association cortex?

Answer 15

• plays a role in complex analysis of incoming information

- brings refinement by which sensory info can be processed

Question 16

What is a cortical map?

Answer 16

Neural representation of regions in the brain where certain processing activities occur.

Question 17

What is the name for the cortical map of humans?

Answer 17

Homunuculus

Question 18

What is the name for the cortical map of cats?

Answer 18

Felunculus

Question 19

What is the name for the cortical map of dogs?

Answer 19

Cannunculus

Question 20

The amount of space on the sensory cortex devoted to each body part is _______ to the sensitivity of that part.

Answer 20

Proportional

Question 21

How many categories are the neuronal pathways within the sensory system divided into?

Answer 21

2

Question 22

What are the major categories of neuronal pathways in the sensory system?

Answer 22

1) Spinothalamic tract

2) Dorsal Colum

Question 23

What makes the dorsal colum sensory tract different from the Spinothalamic tract?

Answer 23

Dorsal Colum has an additional synapse at the brain stem and medulla region

Spinothalamic tract synapses directly at the spinal cord level and then the cerebral cortex in the thalamus. (No synapse in the medulla/brain stem)

Question 24

What are sensory nerve tracts?

Answer 24

Tracts involved in converting sensory input and taking it to the higher centres of the brain for processing.
- ascending pathways

Question 25

What are motor nerve tracts?

Answer 25

Tracts involved in taking motor output to end organs

- descending pathways

Question 26

What are the two motor nerve tracts?

Answer 26

1) Pyramidal Tract

2) Extrapyramidal Tract

Question 27

Which motor nerve tract has an extra synapse in the brain stem and medulla region?

Answer 27

Extrapyramidal Tract

Question 28

How many extrapyramidal tracts are there?

Answer 28

4

Question 29

What are the different types of extrapyramidal tracts?

Answer 29

1) Rubrospinal tracts
2) Vestibuolospinal tracts
3) Reticulospinal tracts
4) Tectospinal Tracts

Question 30

Which type of motor tracts are corticospinal tracts?

Answer 30

Pyramidal tracts

Question 31

Which motor tract is responsible for fine motor control skills?

Answer 31

Corticospinal Tract (pyramidal)

Question 32

Which motor tract is responsible for automatic orientation of head and eyes to auditory and visual stimuli?

Answer 32

Tectospinal Tracts

Question 33

Which motor tracts are responsible for subconscious and upright balanced position and wakefulness?

Answer 33

Reticulospinal tracts (wakefulness) and Vestibuolospinal tracts

Question 34

Which motor tract is responsible for voluntary and skilled movements?

Answer 34

Rubrospinal Tracts

Question 35

Why are the direct influence of strokes minimal in vet species unlike humans?

Answer 35

Majority of motor functions in humans are from pyramidal tracts but in domestic species, most are extrapyramidal.