Homeostasis And Disease Presentation

Question 0

What is serum osmolality?

Answer 0

A measure of the number of dissolved particles per unit of water in serum

Question 1

What is the amin of fluid balance?

Answer 1

Maintain normal fluid volume and plasma osmolality

Question 2

How is fluid lost?

Answer 2

Infection
Decreased aldosteronism
Decreased ADH
GI losses

Question 3

What does aldosterone cause?

Answer 3

Salt and water retention in the kidneys

Question 4

What is homeostasis achieved by?

Answer 4

Thirst
Anti-diuretic hormone –> makes you hold on to water and salt
Renin-angiotensin aldosterone system (RAAS)
Atrial natriuretic peptide

Question 5

What triggers thirst?

Answer 5

Hypovolaemia

Hypotension

Question 6

What senses hypovolaemia?

Answer 6

Vascular stretch receptors which then causes vagus stimulation which in turn stimulates the hypothalamus
Angiotensin 2 directly stimulates the hypothalamus

Question 7

What is thirst stimulated by?

Answer 7

Cellular degradation in central brain osmoreceptors which lie outside the blood brain barrier

Question 8

What is the order of the renin-angiotensin aldosterone system?

Answer 8

Angiotensinogen –> angiotensin 1 by renin

Angiotensin 1 –> angiotensin 2 by ace (angiotensin converting enzyme)

Question 9

What is the atrial natriuretic peptide?

Answer 9

Produced, stored and secreted by the muscle cells of the atria
Released in response to atrial stretch
Inhibits renin which causes the decrease in aldosterone secretion, stadium reabsorption and increase in water excretion

Question 10

What changes occur in the kidney with ageing?

Answer 10

Decreases in size and weight
Hyalinosis of arterial walls
Decreased renal blood flow
Decrease in the number and size of nephrons
Increase thickness of basal membrane
Decreased serum renin and aldosterone synthesis
Decreased ability to concentrate urine

Question 11

Thermoregulation changes in ageing

Answer 11

Delay in response to temperature
Impaired shivering
Impaired cutaneous vasoconstriction and slower
Impaired vasodilatation and slower

Question 12

What are the 5 geriatric giants?

Answer 12

Immobility
Instability 
Intellectual impairment 
Incontinence 
Lacrogenic

Question 13

What causes immobility and instability in ageing?

Answer 13

Falls
Due to drugs such as anti histamines
Decreased strength in muscles such as quads
Gait