homeostatic mechanisms

Question 1

what is homeostasis

Answer 1

maintaining constant internal environment of the body

Question 2

role of skin in overheating

Answer 2

1.vasodilation of the blood cells, more blood reaches the surface of the skin, increase heat lost by radiation
2.sweat gland secrete waste, which evaporates, which cools down the body

Question 3

role of skin in overcooling

Answer 3

1.vasoconstriction of the blood cells, less blood reaches the surface of the skin, reduce heat loss by radiation
2.sweat glands stop sweat secretion
3.hair erects to trap air which acts like an insulator to reduce heat loss
4.muscle shiver, increasing respiration rate to release heat

Question 4

what is excretion

Answer 4

removal of metabolic wastes, toxic and excess substances

Question 5

what is ultrafiltration

Answer 5

a passive process where urea, water, salts, glucose and amino acids pass from blood into nephron due to the high blood pressure, forming a fluid called “glomerular filtrate”. (blood cells and plasma proteins don’t pass due to their large size)

Question 6

what is selective reabsorption

Answer 6

1.active process where useful substances are reabsorbed and pass from nephron to blood.
2.all glucose, all amino acids, and some salts are reabsorbed at proximal convoluted tube by active transport
3.water is reabsorbed in the loop of henle by osmosis

Question 7

osmoregulation

Answer 7

1.water loss in sweat increases plasma concentration
2.receptors in the hypothalamus detect increase in plasma concentration
3.hypothalamus sends impulses to the pituitary gland to release ADH
4.ADH increases permeability of the collecting duct, increasing permeability to water, so water is reabsorbed back to the blood
5.volume of urine decreases and becomes more concentrated

Question 8

kidney failure treatment

Answer 8

kidney transplant

Question 9

what is tissue typing

Answer 9

classify the patient’s tissues to find a match genetically similar

Question 10

what is immune suppressive drugs

Answer 10

supress immune system until the kidney is accepted by the body, however they leave the patient more likely to catch infectious diseases

Question 11

advantages of kidney transplant

Answer 11

1.long term solution
2.time saving
3.free lifestyle

Question 12

disadvantages of kidney transplant

Answer 12

1.difficulty to find donor
2.risk of surgery
3.possibility of tissue rejection
4.immunosuppressive drugs

Question 13

disadvantages of renal dialysis

Answer 13

1.time consuming
2.expensive
3.damage to arteries and veins