9- Intro to Metabolism Flashcards
Some hormones are released in response to
sensing of a condition by the very tissue that
synthesizes and secretes the hormone. Give an
example of such a hormone and name the tissue
that secretes it. What is one stimulus of this
hormone release?
Glucose goes to pancreatic Beta cell, which releases Insulin. The detection of high extracellular glucose concentrations stimulates insulin release.
What are the two hormones that largely control
blood glucose? Which is secreted in response to
high blood glucose, and brings blood glucose
down? Which is secreted in response to low blood
glucose, and then increases blood glucose?
glucagon and insulin.
Insulin is released in response to high blood glucose to bring down blood glucose levels.
Glucagon is released in response to low blood glucose to raise blood glucose levels.
Other hormones have a more complicated
stimulation, a cascade involving sensing of a
stimulus, release of a factor from one tissue, the
hormone stimulates release of another factor from
another tissue, and so on… Give an example of
such a hormone and name the tissue that secretes it.
What is the stimulus of this hormone release?
Stress (i.e. pain, hemorrhage, infection, hypoglycemia, exams, …) can elicit a hormone cascade. Stress will stimulate the brain to cause releasing factors to be secreted from the hypothalamus. These releasing factors, will act on the anterior pituitary to secrete corticotropin. Corticotropin acts on the adrenal cortex. Finally, Cortisol is released from the adrenal cortex.
What is the name that describes the chemical
process by which energy is obtained from
biological fuels such as the carbon skeletons of
carbs, fatty acids, or amino acids (or any fuel)?
OXIDATION (of C-skeletons)
We get much of what we are made along with
the energy to keep us going from what we eat. We
can also synthesize from scratch much of what we
get in our diet. Give three examples of nutrient
types animals cannot synthesize themselves that
must be obtained from plant or microbial sources
- vitamins (are required for life)
- essential amino acids
- essential fatty acids.
Why are all tissues outside the liver often called
extrahepatic tissues with respect to metabolism?
That is because extrahepatic means literally “outside the liver”.
The carbon skeletons of amino acids are
degraded to intermediates of carbohydrate
metabolic pathways. A different pathway is
involved in degrading the other important group on
amino acids. What is the other amino acid
component group, and what is the pathway that
carries this out? Give an example of organs that cooperate with each other in handling amino acids.
What are the two organelles that co-operate by
participating in this pathway?
Nitrile group.
The urea cycle takes care of the ammonia that is left over from amino acid degradation.
Organs that cooperate include the liver and the skeletal muscle (and maybe the bladder?)
The organelles that cooperate by participating in this pathway include mitochondria and cytesol
What metabolic pathways are used for energy
by skeletal muscles (both at rest and during contractile activity lasting various lengths of time)?
For each pathway, what limits the utilization of the
pathway (what causes the switch to the next
pathway as the time of intense muscular activity
goes on)? In terms of the rate of energy supplied as
ATP, rank the pathways highest rate to lowest.
- stored ATP
- stored creatine phosphate
- glycolysis (anaerobically)
- carbs (aerobically)
- fatty acids
They switch to the next pathway is time to fully be consumed.
What organ has priority over all the others for the
supply of fuel?
The brain has priority over all others for the supply of fuel.
What organ can be said to be the “brain” of metabolism?
The Liver.
What organ can be said to be the “king” of metabolism?
The heart.
