Hormones and Receptors Flashcards Preview

Endocrine > Hormones and Receptors > Flashcards

Flashcards in Hormones and Receptors Deck (21):
1

What are the major endocrine glands in the body?

Thyroid and parathyroid
Pancreas
Hypothalamus and pitutary gland
adrenal glands
ovaries/testes
placenta in pregnant female

2

What does "paracrine" mean?

specialised cells releases substance and act locally to adjacent cells

3

What does "autocrine" mean?

cells release chemical substance which has effect limited to the cell which released it – numerous white blood cells use this

4

List the chemical classes of hormone

Glucoproteins and peptides
Steroids
Tyrosin and trytophan derivatives (amines)

5

Describe the general idea of the endocrine system

Communication between glands and other tissues achieved by the secretion of a hormone into the blood stream and transport to a target site.
Glands are anatomically distinct but form a functional system.

6

How is specificity of signalling achieved?

- chemically distinc hormones
- specific receptors for each hormone
- distinct distribution of receptors across target cells

7

What are the 6 overall functions of the endocrine system?

- regulation of nutrient metabolism, H20 and electrolyte balance
- enabling changes to stress
- promoting growth and development
- conrolling reproduction
- regulating red blood cell production
- controlling and integrating the activites of the cardiovascular and digestive systems

8

In terms of synthesis, storage, release and transport what happens to amine hormones?

pre-synthesised, stored in vesicles
released in response to increased intracellular Ca2+ - Ca2+ dependent exocytosis
hydrophilic - transported mainly free in plasma

9

In terms of synthesis, storage, release and transport what happens to peptides and proteins hormones?

pre-synthesised (usually from a longer precursor) stored in vesicles
released in response to increased intracellular Ca2+ - Ca2+ dependent exocytosis
hydrophilic - transported mainly free in plasma

10

What synthesises the precursor protein in peptide and protein hormone synthesis?

Rough ER

11

In terms of synthesis, storage, release and transport what happens to peptides and proteins hormones?

Synthesised and secreted on demand (not stored in vesicles!)
Hydrophobic and transported in plasma mainly bound (~90%) to plasma proteins - only "free" is biologicaly active

12

What are all steroid hormones derived from?

Cholesterol

13

What is the purpose of carrier proteins?

-increase amount transported in blood
-prevent rapid excretion by filtration at the kidney

14

Give some exaples of important general carrier proteins.

Albumin and transthyretin

15

Name 3 importat specific carrier proteins.

Cortisol-binding globulin
Thyroxine-binding globulin
Sex steroid- binding globulin

16

Give another function of circulating carrier proteins?

Act as a buffer and reervoir that helps to maintain relatively constant concentrations of free lipophiic hormone in the blood - free and bound hormone are in equilibrium

17

What are the 3 methods of control of hormonal levels?

- negative feedback
- neuroendocrine (elicits a sudden burst in secretion to meet a specfic stimulus)
- diurnal rhythm

18

What are the 3 groups of hormone receptors?

GPCR
Receptor kinases
Nuclear receptors (3 classes)

19

Of the 3 types of hormone receptor, which one is the odd one out and why?

Nuclear receptors - they are intracellular receptors whereas GPCR and receptor kinases are cell surface receptors

20

Which class of nuclear receptors is when unbound, found in the cytoplasm bound to inhibitory heat shock protein?

Class 1

21

Which class of nuclear receptors does thyroiod hormone bind to?

Hybrid class