homeostasis

Question 1

What are the three types of hormones?

Answer 1

peptide, steroid amino acid derivative

Question 2

What are some examples of a peptide hormone and how does it differ to the others?

Answer 2

Peptide - insulin, growth hormone, TSH ● From short chain of AA to small proteins ● Some glycoproteins ● Hydrophilic - receptor

Question 3

Some examples of amino acid derivatives and how they differ?

Answer 3

Amino-acid derivative- adrenaline, T4, T3 ● synthesised from tyrosine

Question 4

Definition of osmolality and osmolarity

Answer 4

Osmolality - measure of the number of dissolved particles per kg of fluid.
Osmolarity - measure of the number of dissolved particles per L of fluid.

Question 5

define oncotic pressure

Answer 5

a form of osmotic pressure derived from proteins mostly albumin

Question 6

What is the homeostasis mechanism of water loss from the extracellular fluid?

Answer 6

Water loss from ECF ●
↑ solute or ↓ fluid results in an ↑ osmolality
● Detected by osmoreceptors in hypothalamus
● Release of antidiuretic hormone (ADH) from posterior pituitary
● ADH acts by increasing water reabsorption in the kidneys ● Dilutes solute and returns ECF water to normal.

Question 7

What is the homeostasis mechanism of decreased renal blood flow?

Answer 7

Decreased renal blood flow
● ↓ water in ECF results in ↓ circulating volume results in ↓ renal blood flow
● Kidney release of Renin and activation of RAAS
● Angiotensin II and aldosterone increase Na+ reabsorption (exchange K+ and H+) bringing water. Also stimulates ADH

Question 8

What are three causes of water excess?

Answer 8

high intake
decreased loss
decrease adh

Question 9

What is oedema and name some types

Answer 9

Oedema - excess water in the intercellular tissue space

inflammatory (leakage), Venous (increased end pressure), Lymphatic (blocked), Hypoalbuminaemic

Question 10

What is serous effusion?

Answer 10

Excess water inbody cavity

Question 11

Types of cell communication

Answer 11

Enodcrine
Nervous
Immune

Question 12

Water distribution in the body

Answer 12

Total is 42L 60% of body weight
40% intracellular
20% extracellular 14L
Interstitial 10
Plasma 3
Transcellular 1

Question 13

What is hypernatraemia

Answer 13

Excess sodium

Question 14

What is hypercalacaemia

Answer 14

Excess calcium

Question 15

raas system

Answer 15

renin released from kidney and converts angiotensinogen to angiotensin 1
ace from lungs convertes ang 1 to ang2
ang 2 can activate adh , aldosterone and sympathetic ns

Question 16

how is raas system activated

Answer 16

when bp decreases , detected by juxtaglomerular cells in afferent arteriole of kidneys
or decrease in nacl detected by macula densa of distal convoluted tube
renin in then released from kidneys

Question 17

How does raas system increase blood pressure

Answer 17

Ang2 is a vasoconstrictor causes blood vessels to narrow

Ang2 also increases secretion of hormone aldosterone from adrenal cortex

Question 18

3 modes of communication and how

Answer 18

autocrine- acts on the same cell
paracrine- secrete into ECF acts on neighbouring cells
enodcrine- secretion into blood acts on distant cell

Question 19

characteristics of peptide hormone

Answer 19

water soluble
binds to cell surface membrane
fast acting
premade and stored in vesicles

Question 20

what does adh do

Answer 20

act on ap 2 receptors on collecting ducts

increased permeability of collecting ducts , more ecf higher bp

Question 21

characteristics of steroid hormone

Answer 21

made from lipid cholestrol
lipid soluble
diffuse through cell surface membrane 
slow acting
oestrogen and testosterone

Question 22

main intracellular and extracellular ion ion

Answer 22

K+ intra

Na+ extra

Question 23

role of aldosterone

Answer 23

increase na reabsorption in ascending limb of LOH

Question 24

obligatory h20 movement

Answer 24

h2o follows na+

Question 25

Difference between endocrine and exocrine

Answer 25

Endocrine is released into blood not via a duct

Exocrine released into blood via a duct