32. Specialized Tissues, Stem Cells And Tissue Renewal

Question 1

What is the role of the sensory cells that are present in the sensory epithelia?

Answer 1

1. Act as transducer

2. Convert environmental signal to electrical form, for CNS interpretation

Question 2

Are the sensory epithelial cells highly conserved throughout evolution?

Answer 2

Yes

Question 3

What are the sensory cells in the nose?

Answer 3

1. Olfactory sensory neurons

Question 4

What are the sensory cells present in the ear?

Answer 4

Auditory hair cells

Question 5

What are the sensory cells present in the eyes?

Answer 5

Photoreceptors

Question 6

What is located on the apical end of the sensory cells?

Answer 6

Structure that will detect the external stimulus and convert it to change the membrane potential

Question 7

What is located at the basal end of the sensory cells?

Answer 7

Synapses with neurons to specific brain regions

Question 8

What are bipolar neurons with a dendrite facing the extracellular environment, and where does the axon travel?

Answer 8

1. Olfactory neurons

2. Axon travels along olfactory nerve to the olfactory bulb

Question 9

What type of neuron is the olfactory neuron and how does it run to the brain?

Answer 9

1. Bipolar neuron, with dendrites facing the extracellular environment
2. Axons run with the olfactory nerve to the olfactory bulb

Question 10

What are the olfactory neuron supporting cells?

Answer 10

1. Cells present between neurons that anchor and separate neurons from one another.

Question 11

What are the cells that are in contact with the basal lamina referred to as?

Answer 11

Stem cells

Question 12

Where are odorant receptor proteins found in olfactory receptors?

Answer 12

Found on free surfaces of cilia

Question 13

What type of receptor are the odorant receptors that are located on free cilia surfaces?

Answer 13

G protein coupled receptors

Question 14

How do olfactory neurons generate an action potential when that specific odorant receptor is bound with an odor?

Answer 14

1. GPCR are activated to form cAMP
2. cAMP opens ion channels allowing sodium/calcium influx into cell
3. Forming action potential

Question 15

What do the olfactory neuron action potentials act on?

Answer 15

1. Act on glomeruli located on olfactory bulbs on each side of brain

Question 16

What is the average turn over for an olfactory neuron?

Answer 16

30 days

Question 17

What is the rare case of adult neurogenesis, specifically in the CNS?

Answer 17

1. Regeneration of olfactory axons, receptors, and bulb attachment

Question 18

Why is olfaction considered to be linked with neurodegenerative disorders?

Answer 18

1. Aging individuals display reduced activity in olfaction

Question 19

What is an initial clinical finding in cases of idiopathic Parkinson’s disease?

Answer 19

1. Reduced sense of smell

Question 20

What parts of the brain have been shown to contain stem cells?

Answer 20

1. Ventricles of forebrain. These migrate to olfactory bulb

2. Hippocampus. Memory and learning region

Question 21

What are neurospheres (clusters of neural stem cells) able to differentiate into?

Answer 21

1. Neurons

2. Glial cells

Question 22

How are some non-mammalian animals able to regenerate amputated limbs?

Answer 22

1. Cells de-differentiate to embryonic cells
2. Embryonic cells proliferate to form limb bud.
3. Cells then re-differentiate to tissue specific

Question 23

What is the sensory epithelium?

Answer 23

Specialized epithelium covering nose, eyes and ears