BIO 181 ASU EXAM 3 Short Answers
Briefly explain why the action potential flows only from the axon hillock to the
terminal web.
The action potential originates from the axon hillock which initiates the flow of the action
potential because of the presence of higher density voltage-gated ion channels.
List the 4 types of glial cells and list a phrase to describe their function.
- Microglia: cleans up cellular debris
- Astrocytes: support and repair neurons
- Schwann Cells: myelinates axons of the neurons in the PNS
- Satellite: form the brain-blood barrier within the CNS
How do the glial cells (i.e., myelin sheath) speed up the firing of neurons?
The cell wraps extensions of a fatty insulating substance (myelin) around the axons of
neurons.
What could the stress of taking an exam do to your glucose levels in various
parts of the body?
It can raise the glucose levels in your blood
When epinephrine is released it triggers activation of which part of the Autonomic
Nervous System?
The adrenal medulla, which then triggers the hypothalamus
Where do fats in the body play a role in balance between glucose and glycogen
When blood glucose levels fall, the pancreas stops releasing insulin, and cells switch to
using glycogen and fat for energy
Explain how insulin and glucagon regulate the balance (i.e, homeostasis)
between glycogen and glucose when epinephrine (i.e., adrenalin) is not involved.
Insulin and glucagon work in what's called a negative feedback loop. During this
process, one event triggers another, which triggers another, and so on, to keep your
blood sugar levels balanced.
During digestion, foods that contain carbohydrates are converted into glucose. Most of
this glucose is sent into your bloodstream, causing a rise in blood glucose levels. This
increase in blood glucose signals your pancreas to produce insulin.
The insulin tells cells throughout your body to take in glucose from your bloodstream. As
the glucose moves into your cells, your blood glucose levels go down. Some cells use
the glucose as energy. Other cells, such as in your liver and muscles, store any excess
glucose as a substance called glycogen. Your body uses glycogen for fuel between
meals.
Glucagon works to counterbalance the actions of insulin.
About four to six hours after you eat, the glucose levels in your blood decrease,
triggering your pancreas to produce glucagon. This hormone signals your liver and
muscle cells to change the stored glycogen back into glucose. These cells then release
the glucose into your bloodstream so your other cells can use it for energy.
Briefly explain why the action potential flows only from the axon hillock to the
terminal web.
The action potential originates from the axon hillock which initiates the flow of the action
potential because of the presence of higher density voltage-gated ion channels.
List the 4 types of glial cells and list a phrase to describe their function.
- Microglia: cleans up cellular debris
- Astrocytes: support and repair neurons
- Schwann Cells: myelinates axons of the neurons in the PNS
- Satellite: form the brain-blood barrier within the CNS
How do the glial cells (i.e., myelin sheath) speed up the firing of neurons?
The cell wraps extensions of a fatty insulating substance (myelin) around the axons of
neurons.
What could the stress of taking an exam do to your glucose levels in various
parts of the body?
It can raise the glucose levels in your blood
When epinephrine is released it triggers activation of which part of the Autonomic
Nervous System?
The adrenal medulla, which then triggers the hypothalamus
Where do fats in the body play a role in balance between glucose and glycogen
When blood glucose levels fall, the pancreas stops releasing insulin, and cells switch to
using glycogen and fat for energy
Explain how insulin and glucagon regulate the balance (i.e, homeostasis)
between glycogen and glucose when epinephrine (i.e., adrenalin) is not involved.
Insulin and glucagon work in what's called a negative feedback loop. During this
process, one event triggers another, which triggers another, and so on, to keep your
blood sugar levels balanced.
During digestion, foods that contain carbohydrates are converted into glucose. Most of
this glucose is sent into your bloodstream, causing a rise in blood glucose levels. This
increase in blood glucose signals your pancreas to produce insulin.
The insulin tells cells throughout your body to take in glucose from your bloodstream. As
the glucose moves into your cells, your blood glucose levels go down. Some cells use
the glucose as energy. Other cells, such as in your liver and muscles, store any excess
glucose as a substance called glycogen. Your body uses glycogen for fuel between
meals.
Glucagon works to counterbalance the actions of insulin.
About four to six hours after you eat, the glucose levels in your blood decrease,
triggering your pancreas to produce glucagon. This hormone signals your liver and
muscle cells to change the stored glycogen back into glucose. These cells then release
the glucose into your bloodstream so your other cells can use it for energy.
