Physiology of the Endocrine system( Prof Joji)

Question 1

List 5 functions of hormones

Answer 1

Growth
Development
Reproduction
Homeostasis
Response to external stimuli and stress

Question 2

Name 8 NB endocrine glands

Answer 2

Pineal gland
Pituitary gland
Parathyroids
Thyroid gland
Adrenals
Pancreas
Ovaries
Testes

Question 3

Classifications of hormones according to how they act, explain(3)

Answer 3

Paracrine hormones- made and act locally.
Autocrine hormones- act on the cell that synthesized them and neighbouring cells of the same type.
Endocrine hormones- released into the bloodstream to other tissues or organs.

Question 4

What is the active form of testosterone

Answer 4

Dihydrotestosterone

Question 5

Name the protein that hormones binds to for transportation purposes

Answer 5

Albumin

Question 6

Name two types of hormones

Answer 6

Steroid hormones
Peptide hormones

Question 7

Parent of all steroid hormones

Answer 7

Cholesterol

Question 8

Name the transport systems for thyroxine and cortisol.

Answer 8

Thyroid-binding globulins
Cortisol-binding globulins

Question 9

Which types of hormones have a longer half life

Answer 9

Steroid hormones

Question 10

How do the two types of hormones exert their functions on cells

Answer 10

Peptide hormones bind to the receptors found on the cell membrane.
Steroid hormones bind to receptors found in the cytosol or nucleus.

Question 11

How are hormones inactivated?

Answer 11

They are metabolised and the metabolites are excreted.

Question 12

Briefly explain the process of steroid hormone mode of action

Answer 12

Some steroid hormones move on their own in blood plasma to the cell, some uses protein carriers.
Some steroid hormones bind to the cell surface receptor that use second messenger systems producing rapid cellular responses.
Some diffuse into the cell and either bind to the cytoplasmic receptor or nuclear receptor.
The receptor-hormone complex inside the nucleus binds to the DNA and activates or represses one or more genes.
The activated genes create mRNA which then moves out of the nucleus and proceeds with translation forming new proteins for cell processes.

Question 13

Explain the processes that take place in the post-translational modification of hormones

Answer 13

1.mRNA in the ribosome binds amino acids to a peptide chain called preprohormone, the signal sequence of amino acids guide the peptide chain into the ER lumen.
2. Enzymes in the ER lumen chop off the signal sequence of aa creating an inactive prohormone.
3. The prohormone then passes from the ER through the golgi.
4. The secretory vesicle containing the prohormone and enzymes buds off the golgi. The enzymes chop off the prohormone into active peptides plus additional peptide fragments.
5. The secretory vesicle releases its content into the extracellular space via exocytosis.
6. The hormone then moves into the circulation for transport to its target.

Question 14

Name 3 ways in which hormonal control can occur

Answer 14

Negative feedback
Specific components
Sympathetic nervous system