Diabetes and Endocrinology

Question 1

Define endocrine communication

Answer 1

Hormones will travel through the blood until they reach a target cell which has a receptor for that specific hormone (No receptor = no response)

Question 2

Define neuro-endocrine communication

Answer 2

The release of neuro-homrones from the posterior pituitary gland which travel directly into the blood to target organs which have a receptor for that hormone

Question 3

What is the purpose of a hormone binding to a cell receptor

Answer 3

To alter the activity within that cell

Question 4

Where are the receptors for peptide hormones found?

Answer 4

On the cell surface

Question 5

What are autocrine signals?

Answer 5

Where cells secrete chemicals which bind to their own cell

Question 6

What are paracrine signals?

Answer 6

Where chemicals diffuse within the ECF to bind to a neighboring cell

Question 7

What are peptide hormone comprised of?

Answer 7

Chains of amino acids

Question 8

Which kind of hormone is the most common?

Answer 8

Peptide hormones

Question 9

What are peptide hormones synthesised as in advance of their requirement and then what are they cleaved into?

Answer 9

preprohormone

Prohormone

Question 10

In what form are peptide hormones stored as?

Answer 10

Prohormone

Question 11

What is released into the blood alongside the peptide hormones and why is this clinically useful?

Answer 11

Peptide fragments

Inactive fragments (C-peptide) can be measured clinically

Question 12

Why is C-peptide measured within the body and what is it ?

Answer 12

An inactive peptide fragments

Insulin is metabolized faster than C-peptide therefore it is easier to measure

Question 13

What is the fastest channel found om the cell surface?

Answer 13

Ion channels

Question 14

What 2 kind of cell surface receptors are found to be areas where peptide hormones bind?

Answer 14

G-coupled channels

Tyrosine kinase receptors

Question 15

When a peptide hormone binds to the cell surface receptors what occurs within the cell?

Answer 15

2nd messenger system is activated which opens the ion channel
Altering of gene expression

Question 16

What are the majority of amine hormones derived from?

Answer 16

Tyrosine

Question 17

What is melatonin derived from?

Answer 17

Tryptophan

Question 18

What are steroid hormones derived from?

Answer 18

Cholesterol

Question 19

What kind of hormones arent stored and why ?

Answer 19

Steroid hormones, lipophillic nature would cause them to diffuse out of the cell

Question 20

How do steroid hormones travel through the blood stream?

Answer 20

Steroid hormones must be bound to a carrier protein in order to travel through the blood i.e. Albumin.

This also prevents them from degradation and increases their half-life (longer duration of action)

Question 21

What tissues produce steroid hormones?

Answer 21

Gonads (Testes and ovaries)
Adrenal cortex (Corticosteroids)
Placenta (HCG and sex steroids)
Kidney (Vitamin D3)

Question 22

Where are the cell receptors for steroid hormones found?

Answer 22

Within the cell

Question 23

Which are faster cell surface or intracellular receptors ?

Answer 23

Cell surface receptors

Question 24

in order for a steroid hormone to pass the cell surface it needs to be ________

Answer 24

Unbound

Question 25

What is the ratio of unbound to bound plasma within the blood and the cell

Answer 25

The ratio is much in favour of bound steroid hormone, although there has to be a small amount of unbound present to maintain homeostasis

Question 26

What is the law of mass action?

Answer 26

As free hormone leaves the plasma more hormone is released from the carriers in the blood, this is to maintain homeostasis.

Question 27

In what form are steroid proteins stored in the blood and what is this called?

Answer 27

steroid-protein complexes

Resevoir of hormone