Endocrinology Intro

Question 1

How does endocrine signalling work

Answer 1

A hormone is released by a cell and circulated in the blood to target specific receptors on target organs

Question 2

Name the endocrine glands in the body which release hormones from specialised cells

Answer 2

Hypothalamus + pituitary glands

Thyroid glands and parathyroid

Adrenal glands

Pancreas

Ovaries / testes

Question 3

What is another word for ovaries and testes

Answer 3

The gonads

Question 4

It was found that not only endocrine glands release hormones: what else (specialised tissues)

Answer 4

Kidney, platelets , WBC’s , heart muscle

Question 5

Name the 4 ways hormones can interact and explain them

Answer 5

1- SYNERGISTIC : 2 hormones will increase the cellular response instead of 1

2- PERMISSIVE : a presence of 1 hormone will allow the other to work

3- ANTAGONISTIC : 2 hormones which oppose effect

4- COMPETITIVE : 2 hormones similar in structure compete to bind to receptor

Question 6

Give an example of antagonistic hormones

Answer 6

Insulin and glucagon

Question 7

Give an example of competitive hormones

Answer 7

Epinephrine and norepinephrine

Question 8

Name the 3 classes of hormone and what synthesises them

Answer 8

Steroid - produce by modified cholesterol

Peptide - produced by amino acids

Amino acid - produced by modification of tyrosine amino acid

Question 9

Which type of hormone acts on intracellular receptors (hydrophobic)

Answer 9

Steroid - cholesterol is hydrophobic so can pass membrane

Question 10

Which type of hormone is fully hydrophilic so can act on cell surface receptors

Answer 10

Peptide hormones

Question 11

Is amino acid hormones hydrophobic or hydrophilic

Answer 11

Can be both depending on type

Question 12

What modifies cholesterol into steroid hormones

Answer 12

Enzymes

Question 13

Why is steroid hormones bound to proteins when produced

Answer 13

Because they are hydrophobic

Question 14

When are steroid hormones produced

Answer 14

When a hormone is in demand - they ARE NOT STORED

Question 15

How can steroids produce both gonad hormones such as testosterone and also adrenal gland hormones like cortisol for stress?

Answer 15

Because they will have different enzymes in the different glands to modify cholesterol into different hormones

Question 16

Name the types of receptor a steroid hormone can activate / bind to (intracellular)

Answer 16

Ligand receptor complex inducing transcription (TF receptor)

Question 17

What are the 3 domains of a ligand binding TF receptor

Answer 17

Dna binding

Ligand / hormone binding

Transcription inducing domain

Question 18

Explain what happens to a receptor in the cell when steroid hormones bind

Answer 18

There is a conformational change when it binds to the domain

Hinge region changes and opens up the receptor to expose the dna binding site and transcription inducer

Enters nucleus and allows transcription

Question 19

What stops steroid hormones binding to intracellular receptors when transcription isn’t needed

Answer 19

Hsp70 protein inhibitor (blocks the hormone binding domain)

Question 20

Which hormone is stored prior to release

Answer 20

Peptide hormones

Question 21

What is the inactive form of a peptide hormone called

Answer 21

Prepro hormone

Question 22

Where are prepro hormones stored before release

Answer 22

In vesicles

Question 23

What type of receptors do peptide hormones usually bind to which then activates what…

Answer 23

Cell surface G protein coupled receptors

Activating usual cascade then secondary messengers which then allow phosphorylation

And cellular response

Question 24

Are amino acids released immediately like the steroid hormones?

Answer 24

Yes. They release as soon as made from tyrosine

Question 25

Name an example of an amino acid hormone which acts intracellular

And another that’s cell surface

Answer 25

Thyroid hormone = intracellular

Epinephrine (also thyroid gland) = cell surface

Question 26

What would be a short term response example by cells when hormones bind

Answer 26

Change in metabolism eg change in glucose conc when insulin binds

Question 27

What would be a long term response example by a cell

Answer 27

Gene expression eg when steroid hormones bind

Question 28

Name the 4 ways hormones can be released and explain

Answer 28

1- continuous release

2- pulsatile : in short bursts

3- circadian : according to cycles eg day and night

4- released by stimulus : when stimulus is detected cause release eg glucose levels

Question 29

Give an example of circadian hormones

Answer 29

Melatonin release only at night

Question 30

Which hormone is released in short bursts (PULSATILE)

Answer 30

Gonadoptrophin releasing hormone

Question 31

Which hormone is released continuously

Answer 31

Thyroid hormone

Question 32

How are hormones activated and give an example

Answer 32

Post release modifications such as oestrogen modified from androgens

Question 33

How are peptide hormones activated

Answer 33

Cleaving of amino acids

Question 34

Name 5 ways to control hormones

Answer 34

1- modification : increase eg by cleaving peptides and decrease activity too

2- degradation/ excretion

3- receptor desensitisation

4- termination of intracellular responses

5- negative feedback

Question 35

Give an example of a hormone receptor which gets desensitised to control the effect of hormone

Answer 35

Androgenic receptors stop effect of adrenaline

Question 36

Give an example of how intracellular responses can be terminated to control hormone effect

Answer 36

Phosphatase / de phosphorylation of proteins

Question 37

Name 3 ways negative feedback works

Answer 37

1- metabolites : eg glucose level detected and = insulin release

2- by hormone level itself

3- by a tropic hormone which is released by pituitary/hypothalamus

Question 38

Where are androgens like testosterone produced

Answer 38

Gonads and also adrenal glands (they are steroid hormones)