Module 6

Question 1

What are the special senses? (5)

Answer 1

• vision
• hearing
• taste
• smell
• equilibrium

Question 2

What are the somatic senses? (5)

Answer 2

• touch
• temperature
• pain
• itch
• proprioception

Question 3

What are the somatic stimuli? (2)

Answer 3

• muscle length and tension

- proprioception

Question 4

What are the visceral stimuli? (8)

Answer 4

• blood pressure
• distensions of gastrointestinal tract
• blood glucose concentration
• internal body temperature
• osmolarity of body fluids
• lung inflation
• pH of cerebrospinal fluid
• pH and oxygen content of blood

Question 5

What does a sensory neuron generally do? How does this occur?

Answer 5

A sensory neuron with a transducer (receptor) converts a physical stimulus into an intracellular signal.
This usually occurs through the opening or closing of gated channels.

Question 6

What receptors are chemoreceptors? (4)

Answer 6

• blood chemoreceptors
• nociceptors
• hypothalamic glucose sensing neurons
• taste, smell

Question 7

What receptors are mechanoreceptors? (5)

Answer 7

• touch
• proprioceptors
• nociceptors
• auditory (hair cells)
• balance (cupula)

Question 8

What receptors are photoreceptors? (1)

Answer 8

vision (rods and cones)

Question 9

What receptors are thermoreceptors? (2)

Answer 9

• thermal receptors

- nociceptors

Question 10

Where is visceral sensory information integrated?

Answer 10

In the brainstem and spinal cord.

Question 11

Where are almost all special and somatic sensory neurons routed?

Answer 11

Through the thalamus

Question 12

special senses vs somatic senses

Answer 12

special senses have dedicated cortical regions.

somatic senses are integrated in the primary somatosensory cortex.

Question 13

What are the 4 properties of a stimulus that the CNS distinguishes?

Answer 13

1. modality
2. location
3. intensity
4. duration

Question 14

What is meant by modality?

Answer 14

The physical stimuli being sensed, determined by sensory receptor being activated, temperature vs touch receptor, and where the pathways terminate in the brain.

Question 15

Why is the location of a stimulus important?

Answer 15

Stimuli are coded according to which receptive fields are being activated. Most sensory stimuli for specific regions of the body are projected to particular areas of the somatosensory cortex.

Question 16

What does sound localization depend on?

Answer 16

The timing in which sound reaches the auditory cortex from each ear.

Question 17

What is intensity of a stimulus determined by?

Answer 17

The number of receptors being activated (population coding) and the frequency of action potentials coming from those receptors (frequency coding).

Question 18

How is the duration of a stimulus determined?

Answer 18

determined by how long action potentials are being activated.

Question 19

tonic receptors vs phasic receptors

Answer 19

Tonic receptors are slowly adapting receptors that respond for the duration of the stimulus.
Phasic receptors rapidly adapt to a constant stimulus and turn off.

Question 20

What does the autonomic nervous system control?

Answer 20

Involuntary control of smooth muscle, cardiac muscle, many glands, and some adipose tissue.

Question 21

sympathetic vs parasympathetic

Answer 21

Sympathetic: fight or flight
Parasympathetic: rest and digest

Question 22

what do autonomic pathways consist of?

Answer 22

Two neurons that synapse in an autonomic ganglion.

Question 23

Preganglionic neuron vs postganglionic neuron

Answer 23

Preganglionic neuron: extends out toward periphery

Postganglionic neuron: communicates with target cell

Question 24

What is more common in autonomic pathways: convergence or divergence?

Answer 24

Divergence is more common. 1 preganglionic neuron will synapse with 8 or 9 postganglionic neurons.

Question 25

Where are ganglia found in the sympathetic pathway? Where do they originate? How do the sizes of pre and post ganglionic neurons differ?

Answer 25

- Ganglia are mainly found in two ganglion chains running alongside the vertebral column - preganglionic neurons originate in the thoracic and lumbar regions - short preganglionic neurons, long postganglionic neurons

Question 26

Where do ganglia originate in the parasympathetic pathway? Where are they located? How do the sizes of pre and post ganglionic neurons differ?

Answer 26

- preganglionic neurons originate in the brainstem and exit via cranial nerves or from the sacral region of the spinal cord. - mainly located on or near their target organs. - long preganglionic neurons, short postganglionic neurons.

Question 27

Which cranial nerve contains 75% of all parasympathetic neurons?

Answer 27

Cranial nerve X (vagus nerve)

Question 28

What chemical signals do sympathetic pathways use? (2)

Answer 28

acetylcholine and norepinephrine

Question 29

What chemical signals do parasympathetic pathways use?

Answer 29

acetylcholine

Question 30

What is the adrenal medulla? What is it associated with?

Answer 30

a specialized neuroendocrine structure associated with the sympathetic nervous system.

Question 31

What are catecholamines?

Answer 31

Signal molecules formed from tyrosine; include epinephrine, norepinephrine, and dopamine.

Question 32

What do autonomic pathways target? Where are receptors located?

Answer 32

- target smooth and cardiac muscle, many exocrine glands, a few endocrine glands, lymphoid tissue, and some adipose tissue. - receptors are not clustered under varicosities, neurotransmitter diffuses to receptors.

Question 33

What are the primary autonomic neurotransmitters? Where can they be synthesized?

Answer 33

- primary neurotransmitters are acetylcholine and norepinephrine - can be synthesized in the varicosities

Question 34

What are sympathetic adrenergic (NE and E) receptors?

Answer 34

- sympathetic adrenergic (NE and E) receptors are all g-protein coupled receptors (metabotropic receptors). - two main categories are alpha (most common) and beta with multiple subtypes.

Question 35

What are parasympathetic cholinergic (ACh) receptors?

Answer 35

- all g-protein coupled receptors | - 5 subtypes

Question 36

Where is receptor M1 of the parasympathetic cholinergic receptors found? What does it do?

Answer 36

- found in the stomach and in salivary glands | - activates phospholipase C

Question 37

Where is receptor M2 of the parasympathetic cholinergic receptors found? What does it do?

Answer 37

- found in the heart | - decreases cAMP, inhibits voltage gated calcium channels, and activates K+ channels

Question 38

Where is receptor M3 of the parasympathetic cholinergic receptor found? What does it do?

Answer 38

- found in the smooth muscle of some organs, the airways, and glands - activates phospholipase C

Question 39

What does the interaction of G-protein coupled receptors with ion channels lead to?

Answer 39

Opening or closing of a channel depending on the g-protein (gi or gs)

Question 40

What does the interaction of G-protein coupled receptors with membrane bound enzymes do? (2 types)

Answer 40

1. Phospholipase C signal transduction pathway: increase in intracellular Ca^2+ mediates a cellular response 2. adenylyl cyclase signal transduction pathway: PKA phosphorylates proteins to cause a cellular response