KP222 Lecture Notes - Lecture 3: Aquaporin, Resting Potential, Sensory Neuron
Lecture 3:
Negative feedback
Concentration of hormones in blood depends on:
1. Rate of hormone secretion
- Stimulation or inhibited by neural or humoral signals (signal in the blood)
- Adrenal gland (kidney): outer (adrenal cortex), inside
- Neural signal: stimulating the release of a hormone (epinephrine from the adrenal
medulla)
- Adrenal gland: helps regulate blood potassium (increase) and the blood is going into the
kidney and the adrenal gland and the increase in blood potassium when it reaches the
adrenal gland causes the release of aldosterone (because blood potassium is too high)
and that signals the kidney to release more potassium in the filtrate (in pee) so you have
a reduction in the potassium of the blood that is leaving the kidney
2. Transport by carrier proteins in blood
3. Metabolism
Case study:
Growth hormone inhibiting hormone (GHIH) is also known as somatostatin, a hormone
released from delta cells of the pancreas. Explain why hypothalamic somatostatin produces
greater inhibition of growth hormone release from the anterior pituitary compared to
pancreatic somatostatin.
- Direct conduit (portal system)
- Somatostatin enters the capillary bed and hormone goes through the portal system so
the hormone is delivered with the same concentration (high)
- Pancreas releases the signal it needs to travel through the body
- Somatostatin: hydrophobic, attaches to another protein which functions as a carrier
- Some are floating free
- Some of the hormones are broken down in the liver so there is degradation in the liver
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1. Degradation by proteolytic enzymes
2. Degradation in the liver
3. Will make it to the target organs (anterior pituitary)
What happens when it reaches the target cell:
- When the receptor receives the hormone it will go through endocytosis (pulled into the
cell)
- Broken down by enzymes then digested
- Taken out of the blood stream
- Somatostatin: digestion as well
Eric Case Study
a. Thyroid gland is not functioning properly
- Not because it is terminal hormone
- There were many hormones between the pituitary
b. Adrenal glands are cancerous
- Sits on top of the kidney, none of the hormones listed on the chart
c. Testes didn’t mature
- Explains reduction in testosterone
d. Pituitary gland is not functioning properly
There was a tumour in the pituitary gland: Cell that produces growth hormone
- Single cell, genetic mutation
- Sites on top of the sella turcia bone: no space to grow
- Binging on the soft tissue of the optic nerves (crossing)
- Osteoporosis: excess hormone growth, not enough testosterone
- Carpal tunnel syndrome: bone that grow the most in the hands they compress the soft
tissue and the median nerve
Make it more difficult for the cells to divide
ACTH: cushions disease
Prolactin: proclatinomia
Treatment:
a benign pituitary tumor had put pressure on the pituitary and disrupted its function
the boy was treated with irradiation (aiming from the left, the right, and the front) to kill
the pituitary and any tumor associated with it
He had an operation to repair the damage to his knee cartilage to put metal pins in both
hips to hold the ball and socket joint together
Success
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The good news was that everything seemed to be working. The patient was 6'4" now,
and had put on muscle, and he now weighed over 220 lbs. X-rays of the skull showed
that the bone saddle the pituitary rested in, which had been pitted, was now healing
over, which indicated that the tumor was no longer putting pressure on the bone and
therefore had probably been destroyed. His hormone levels had stabilized. Of course,
he would need replacement hormones for the rest of his life, especially cortisone,
thyroid, and testosterone, and they had used a growth hormone suppressant for a year.
What treatment could be used to reverse Erics sterility?
a. Growth hormone
b. Luteinizing Hormone
- Enhances testosterone secretion
- Tropic hormone: effects on other hormones
- Production of sexual characteristics
FSH
- Acts on sperm production
- HCG prescribed medication: acts on the same receptors (produced by placenta), allow
for sperm production and motility
c. Thyroid-stimulating hormone
d. Prolactin
Why FSH and LH
Because luteinizing hormone and follicle-stimulating hormones are hormones released
by the pituitary that trigger a variety of events in the testes, including production of
testosterone and production of sperm. Testosterone is made by the testes, and does not
control the testes’ production of sperm.
Now needs jaw surgery
Testosterone?
Growth hormone
- Acromegaly: excess bone growth
Complications or Unrelated
•Woke up one morning unable to see from one eye
- Radiation damaged blood vessels
•Two years later suffered from a stroke (while in a jungle in Costa Rica)
- Related, high blood pressure from drugs
•tested positive for tuberculosis after a trip to China
- unrelated
•Came home from the Marshall Islands with beaver fever, and from Costa Rica with
parasitic botflies burrowing under his skin.
- Unrelated
•At 45 years old, 6'6", 310 lbs complains of frequent night-time waking to urinate
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Document Summary
Concentration of hormones in blood depends on: rate of hormone secretion. Neural signal: stimulating the release of a hormone (epinephrine from the adrenal. Stimulation or inhibited by neural or humoral signals (signal in the blood) Adrenal gland (kidney): outer (adrenal cortex), inside medulla) Growth hormone inhibiting hormone (ghih) is also known as somatostatin, a hormone released from delta cells of the pancreas. Explain why hypothalamic somatostatin produces greater inhibition of growth hormone release from the anterior pituitary compared to pancreatic somatostatin. Somatostatin enters the capillary bed and hormone goes through the portal system so the hormone is delivered with the same concentration (high) Pancreas releases the signal it needs to travel through the body. Somatostatin: hydrophobic, attaches to another protein which functions as a carrier. Some of the hormones are broken down in the liver so there is degradation in the liver: degradation by proteolytic enzymes, degradation in the liver, will make it to the target organs (anterior pituitary)
