hormones

Question 1

Function of hormones

Answer 1

Regulate: chemical composition of internal environment, immune activities, glandular secretions, metabolism, contraction of smooth and cardiac muscle fibres
Growth and repair
Operation of reproductive systems

Question 2

Types of hormones

Answer 2

Lipid soluble = enter cell and alter gene expression
Water soluble = bind to receptor on plasma membrane or on nucleus, producing a secondary messenger

Question 3

examples of lipid soluble hormones

Answer 3

steroids, thyroid and nitric oxide

Question 4

Examples of water soluble hormones

Answer 4

amino acids
peptides
proteins
e.g. human growth hormone, insulin, EPO

Question 5

What stimulates release of hormones

Answer 5

nerve impulse
blood chemistry
other hormones

Question 6

Process of lipid soluble hormone signalling

Answer 6

Hormone diffuses into cell
Hormone binds to receptor within cell forming hormone receptor complex
Hormone receptor complex functions as transcription factor affecting the production of mRNA
This altered gene expression affects the functioning of the cell

Question 7

What are the different messengers in the water soluble hormone response

Answer 7

1st messenger = hormone receptor complex

2nd messenger = cyclic AMP

Question 8

Water soluble hormone cell signalling process
1st step - activation of membrane proteins

Answer 8

Hormone binds to receptor on cell membrane or nucleus
This hormone receptor complex activates G protein
The G protein will activate adenyl cyclase

Question 9

2nd step water soluble hormones signalling

Answer 9

Adenyl cyclase (enzyme embedded in membrane) converts ATP into cyclic AMP

Occurs in the cytosol

Question 10

3rd step water soluble hormones signalling

Answer 10

cyclic AMP will activate protein kinases
Activated protein kinases phosphorylates cellular proteins (adds a phosphate group - from ATP) this will either activate or deactivate the protein
This deactivation and activation will alter cell functioning

Question 11

How are different response to a hormone caused between cells and organelles

Answer 11

different protein kinases are activated in different cells and different organelles

Question 12

4th step water soluble hormones signalling

Answer 12

phosphodiesterase inactivates cAMP so the cells response is deactivated

Question 13

How else can the peptide homrone response stop

Answer 13

Hormones does not continually bind to cell receptor so less activation of adenyl cyclase so less cyclic AMP produced so a reduced response

Question 14

Thymosin function and gland

Answer 14

promotes maturation of T cells
secreted from thymus

Question 15

gastrin function and source

Answer 15

Promotes secretion of gastric juices
Promotes movement of stomach wall

secreted from G cells

Question 16

glucose dependent insulinotropic peptide function and source

Answer 16

stimulates release of insulin from pancreatic beta cells

Source: k cells in the small intestine

Question 17

secretin function and source

Answer 17

Stimulates pancreatic juice (rich in bicarbonate ions) to be released from pancreas (neutralise acidic chyme)

enhances bile production

released from S cells

Question 18

CCK function and source

Answer 18

regulates release of pancreatic enzymes and bile from gallbladder
Causes feeling of fullness
Source = CCK cells from SI

Question 19

EPO function and source

Answer 19

secreted from kidneys
increases rate of conversion of proerythroblasts to reticulocytes

Question 20

function of atrial natriuretic peptide (ANP) and source

Answer 20

decreases blood pressure by vasodilation and causing kidney to secrete water and Na+
released from cells in atria after it has been stretched when accommodating blood

Question 21

Leptin function and source

Answer 21

Hormone for energy balance, secreted when more triglycerides are stored.
Act on circuits that increase energy expenditure.
secreted from adipose tissue

increases activity of FSH and LH

Question 22

Human chorionic gonadotropic (hCG) function and source

Answer 22

stimulates ovary to continue production of progesterone and oestrogen during pregnancy
released from = placenta

Question 23

Aldosterone function

Answer 23

In kidneys, aldosterone stimulates absorption of Na+ which in turn increases water reabsorption
Stimulates the secretion of K+ and H+ ions from kidneys into urine

The increased water reabsorption increases blood volume

Question 24

What is a mineralocorticoid

Answer 24

Steroid hormone released from adrenal cortex that plays a role in regulating levels of salt and minerals in the body

e.g. aldosterone

Question 25

What stimulates the secretion of aldosterone

Answer 25

When BP low, cells in the kidneys secrete renin Renin is an enzyme that converts angiotensinogen into angiotensin I Angiotensin converting enzyme converts angiotensin I to angiotensin II When angiotensin II levels are high in blood, aldosterone is secreted

Question 26

Antidiuretic hormone

Answer 26

secreted from posterior pituaitary enhances water reabsorption from kidneys and causes vasoconstriction to increase BP

Question 27

Growth hormone function

Answer 27

indirectly increases growth by insulin like growth factors to increase protein synthesis for the growth of cells in soft tissue, stimulate osteoblast and growth at epiphysial plate and decreases breakdown of protein for production of ATP GH causes: decreases glucose uptake by body cells so glucose can be used by nerve cells for ATP production, increase lipid breakdown for atp production, = insulin antagonist as it increases blood glucose