Endocrinology

Question 1

Prolactin

Answer 1

• Anterior pituitary - milk secretion?

Question 2

GHRH

Answer 2

• Hypothalamus
• Increase growth hormone
• peptide

Question 3

Somatastatin

Answer 3

• hypothalamus
• Decrease growth hormone

Question 4

Cortisol

1. What triggers release?
2. Pathway for Cortisol production
3. Type of Hormone
4. What it does

Answer 4

1. Stress and low blood glucose. (if we are ready for fight-or-flight, we better make sugar for energy)
2. CRH release(hypothalamus) → ACTH production(adrenal medulla) → Cortisol release(blood)
3. Peptide
4. Facilitates gluconeogenesis, suppresses immune system. As fasting continues, protein and fat breakdown can occur.

Question 5

ADH

Answer 5

• Posterior Pituitary
• increase Aquaporins on the collecting duct
• triggered by osmoreceptors in the hypothalamus

First, it increases the amount of solute-free water reabsorbed back into the circulation from the filtrate in the kidney tubules of the nephrons. Second, AVP constricts arterioles, which increases peripheral vascular resistance and raises arterial blood pressure.[6][7][8]

Question 6

Oxytocin

Answer 6

• Posterior Pituitary
• causes the uterus to contract

Question 7

T3 and T4

1. What triggers release?
2. Give the pathway for T3 and T4 release
3. Type of Hormone (hydrophillicity)
4. What it does

Answer 7

1. Low T3 levels and low metabolic rate
2. TRH release (Hypothalamus) → TSH release (Anterior pituitary) → T3, T4 release (Thyroid)
3. Phobic thyroid
4. It increases the body’s metabolic rate.

T3 is an important factor in metabolism as it regulates many protein syntheses

Question 8

How does the body regulate Ca²⁺ levels? (Use low Ca²⁺ levels as an example)

1. What are the 3 major hormones at play?
2. Describe the pathway

Answer 8

1. PTH (parathyroid), vitamin D (kidneys), Calcitonin
2. Low Ca²⁺ levels →
   
   • Increased PTH release from parathyroid leads to 2 effects:
     
     • Increased Vitamin D from) kidney (to aid active Ca²⁺ reabsorption
     • Decreased Calcitonin from the C cells of the thyroid (when calcitonin is around, osteoclasts are inhibited)

Question 9

Insulin

Answer 9

• Pancreas
• Decrease blood glucose levels, by letting into tissues

Question 10

1. Describe the production of T3 and T4 in follicle cells and
2. It’s entrance into up-regulated cells

Answer 10

1. Iodine is sequestered in the lumen of the thyroid follicles at all times. I₂ is made in this thyroid lumen and interconverted into an iodized product. It is then re-uptaken into the follicle cell cytoplasm where it is cleaved into T4 and T3
2. T4 and T3 are put into the blood at a ratio of 70% : 30%. T4 is inactive, T3 is active. T4 is transported into a cell and interconverted into active T3. It is then sent to the Nucleous for DNA influence on protein synthesis.

Question 11

1. Explain Short feedback and Long feedback Loops.
2. Give 2 major examples

Answer 11

1. Short feedback loops are when the AP hormone turns off the Hypothalamus. Long feedback loops are when the 3rd hormone acts on the AP and/or the Hypothalamus.
2. Thyroid control and Growth hormones
   
   • T3 and T4 shut down is Long feedback. It’s presence shuts down Hypo. and AP.
   • Reproductive organs secrete 2 different feedback hormones.

Question 12

Describe feedback loops as they pertain to reproductive hormones

Answer 12

1. Males: GnRH (Hypo.) → LH and FSH (AP) → Testosterone and inhibin (Testis)
   
   • Testosterone imposes a long neg. feedback on both glands
   • Inhibin imposes a long neg. feedback on AP only
2. Females: GnRH (Hypo.) → LH and FSH (AP) → Progesterone, Inhibin and Estrogen (Ovaries)
   
   • Progesterone imposes a long neg. feedback on both glands
   • Inhibin imposes a long neg. feedback on AP
   • Estrogen imposes a long pos. feedback on Hypothalamus

Question 13

FSH and LH

1. What triggers release?
2. Give the pathway for FSH and LH release and where its signal effects
3. Type of Hormone (hydrophillicity)
4. What it does

Answer 13

1. Growth and development
2. GnRH (Hypo.) → FSH and LH (AP) → testosterone and inhibin (testis) or Progesterone, Inhibin and Estrogen (ovaries)
3. Hydrophillic
4. It Triggers release of hormones that are required for growth and development

Question 14

How does growth hormone influence our body?

Answer 14

• It influences metabolism similar to Cortisol

Question 15

Explain the Insulin pathway

Answer 15

• Insulin acts as a ligand, binds to the outside of the cell.
• the insulin receptor is a tyrosine ligase, which activates vesicles that are full of GLUT 4
• GLUT 4 vesicle is excreted onto the membrane and this places facilitated transporters on the membrane for glucose

Question 16

Compare GLUT 4 with other GLUTs

1. type of transporter
2. location
3. what is needed for it to function?

Answer 16

• GLUT 4
  
  • is a facilitated transporter
  • Skeletal, cardiac and fat tissue
  • gradient and insulin
• GLUT 2 (nonspecific; glucose or galactose) and GLUT 5 (specific; fructose)
  
  • are carrier proteins for glucose on the membrane
  • small intestine, liver and other places….
  • gradient only dog!

Question 17

What inflences to increase Insulin secretion (from islet beta cells)?

Answer 17

1. Incretins secreted from the GI tract in anticipation of glucose. Increases insulin
2. Sympathetic nerves fire when glucose is too low to stimulate glucose release from the liver

Question 18

Describe permissive effects in the body (hormone interactions)

Answer 18

• Epi release causes changes in metabolism
• Thyroid release causes changes in metabolism
• Epi + Thyroid release causes huge changes in metabolism

Question 19

What are Islet cells and what do they do in the Pancreas?

Answer 19

2 Types:

• Alpha - release glucagon
• Beta - release insulin

Question 20

As far as metabolism goes, what can you associate the “fight-or-flight” response with?

Answer 20

• increased Glucose metabolism, *protein metabolism and *fat metabolism

*keep in mind that glucose is primarily effected

Question 21

What is the difference between Type 1 and Type 2 diabetes?

Answer 21

1. Type 1 is an innate lack of insulin
2. Type 2 is receptor insensitivity to insulin

Question 22

For Energy homeostasis in Excercise and Stress: draw 3 graphs plotting Glucose, Glucagon and Insulin over time.

Answer 22

Question 23

What 3 issuse are associated with diabetes?

Answer 23

1. Stroke
2. Heart attack
3. Peripheral artery disease
   
   • Poor blood flow will cause cell damage in capillaries. This is like having a rubber band on your finger for a long time

Question 24

Diabetes Mellitus vs. Diabetes Insipidous

What can diabetes insipidous cause that is really bad?

Answer 24

• diabetes mellitus is a problem

Question 25

Where is Epinephrine secreted? What is its affect?

Answer 25

Adrenal gland * **Chromaffin cells** in Adrenal medulla Affects: 1. Increase HR 2. Dilate Bronchioles 3. Dilate Arteries 4. Stimulate Glycogen breakdown (increase BG)

Question 26

Where is Norepinephrine secreted? What is its affect?

Answer 26

Adrenal Gland * Chromaffin cells of Adrenal medulla Affects: 1. Constrict vessels of digestive and skin. This increases blood to heart, muscles and brain 2. Stimulate Glycogen breakdown (increase BG)