Introduction to endocronology Flashcards Preview

Kidneys and Hormones > Introduction to endocronology > Flashcards

Flashcards in Introduction to endocronology Deck (24):
1

What are the different types of cell to cell communication?

Endocrine signalling
Autocrine signalling
Paracrine signalling
Neural signalling

2

What are the 3 categories of chemical structure of hormones?

Protein or small peptides = ADH

Steroids = cholesterol derivatives

Amines = derivatives of amino acids

3

What are examples of steroid hormones?

Mineralocorticoids - aldosterone

Glucocorticoids - cortisol

Androgens - oestrogen

4

Is cholesterol a hormone?

No - it is a common precursor for many steroid hormones

5

What are examples of amines?

Epinephrine - adrenaline

Thyroxin

6

What do epinephrine and thyroxin have in common?

Both derive from the amino acid tyrosine

7

What determines the way hormones are transported in the blood?

Chemical structure

8

How do peptide hormones and amines travel?

They are hydrophilic

Travel free in solution

9

How do steroid and thyroid hormones travel?

They are hydrophobic

Carried bound to plasma proteins

10

Are protein bound hormones filtered easier at the kidney glomerulus than free floating hormones?

No

11

What types of bonds hold the proteins and the hormones together?

Van der Waals forces

12

Names of proteins that bind to hormones

Sex hormone-binding proteins

Thyroxin-binding protein

Albumin

13

Where are the hormones receptors found?

Some are on the CSM and Some are on nucleus

14

What types of hormones have receptors on CSM?

Hydrophylic hormones

15

What happens when hydrophilic hormones bind to their receptor on CSM?

They relay the information outside the cell into an intracellular response

Interaction of receptor and hormone results in a conformational change in the protein shape

This activates intracellular proteins and releases second messengers that bring about cell responses

Second messengers affect targets inside the cell

16

What are common second messengers?

cAMP

CGMP

Ca2+

IP3

17

What happens when hydrophobic hormones enter cells?

Can cross the nuclear membrane

Interact with genetic material to enhance or decrease gene expression

18

How does oestrogen bring about changes in the cell?

Activates receptors in the cell nucleus

Activated receptors dimerise

These receptors directly affect gene expression - no need for second messengers

19

What are the two types of cell membrane receptors?

Tyrosine kinase receptors
G-protein coupled receptors

20

How does activation of the G-protein coupled receptors bring about cellular changes?

Interaction of hormone with the receptor brings about a change in shape

There is separation of the subunits of the G-proteins - alpha, beta and gamma

G - protein alpha targets the protein adenynyl cyclase which catalyses formation of cAMP

cAMP carries out different funcitons

21

What are the structural features of G-protein coupled receptors

They cross the membrane 7 times

Linked to G-proteins via GDP

G-protein is made of 3 sub-untis: alpha, beta and gamma

22

What effect does cAMP have in different tissues?

In cardiac cells - increases heart rate and contractility

In lung cells - causes bronchodilation via relaxation of bronchial smooth muscle

In liver - enhances glycogenolysis to increase blood glucose

23

What happens upon activation of tyrosine kinase receptors?

Two subunits form the receptor - dimerise when hormone activates it

Dimerised receptors catalyse phosphorylation of proteins

When proteins become phosphorylated = become active and activates other proteins inside the cell

24

What is a kinase?

Enzyme that catalyses the transfer of phosphate group s from high energy molecules to proteins