3

Question 1

There are 5 main homeostatic systems:

Answer 1

Temperature control 
Osmolality (ADH pathway) 
Glucose (blood sugar level) 
Oxygen homeostasis 
Coagulation 

think of “TOGO C’est”

Question 2

what is homeostasis

Answer 2

The physiological process by which the internal systems of the body are maintained at equilibrium despite variations in the external conditions. NOT unchanging state but a dynamic state of equilibrium.

Question 3

What are the three factors on which homeostatic control depends on =

Answer 3

sensor
control centre
effector

Question 4

Give an example of a negative feedback homeostatic mechanism and how does it work?

Answer 4

Temperature control:

Increased body temperature
Sensor: hypothalamus’ heat centers

Control Centre: causing vasodilation to emit heat and sweating to cool down.

Effector:

Decreased body temperature

Sensor: hypothalamus

Control Centre: causing the contraction of peripheral vessels and shivering

Effector: generates heat

Question 5

explain how glucose control works

Answer 5

rising blood glucose level lead to the release of insulin by the pancreas. this will promote glucose transformation to glycogen int he lier and stimulates glucose uptake by cell.

decreased blood glucose leads to pancreatic release of glucagon which stimulates glycogen breakdown into glucose from the liver

Question 6

What is the normal blood glucose level

Answer 6

90mg/100mL

Question 7

explain how oxygen levels are controlled

Answer 7

Detection of low oxygen:

Sensor: carotid bodies (bifurcation of carotid artery)/renal cortex

Control centre: Erythropoietin production (EPO) from the kidneys stimulate the bone marrow to produce more RBCs

Effector: so increase the oxygen carrying capacity and correct hypoxia. When physiological levels are established, EPO production ceases.

Question 8

How is osmolality controlled

Answer 8

Sensor: in hypothalamus – supraoptic nucleus (SON)
•Rise in concentration of extracellular fluid leads to
•Secretion of ADH (same thing as vasopressin) from posterior pituitary
•Correct concentration of ECF detected by SON
•ADH turned off
•Renal absorption of water reduced.

ADH opens up pores to let water be absorbed back into the body.

Question 9

What is diabetes insipidus

Answer 9

In diabetes insipidus, the lack of production of AVP means the kidney cannot make enough concentrated urine and too much water is passed from the body. So main symptom is polyuria (peeing a lot) and extreme thirst, polydipsia.

Question 10

Explain blood clotting mechanisms

Answer 10

blood vessels tears, platelets are recruited to site of injury and release of chemicals to clot.