Homeostasis

Question 1

Homeostasis

Answer 1

The maintenance of a relatively constant internal environment

Question 2

Factors that need to be kept stable

Answer 2

Intersitial fluid plasma
Ph
Temperature
Hormone levels
Blood gases such as o2 or co2

Question 3

Normal levels of potassium

Answer 3

3.5-4.5 mM

Question 4

What’s considered Hyperkalaemia

Answer 4

Concentration of k+ ions exceeds 5.0mM

Question 5

Above what concentration of K+ is considered a medical emergency

Answer 5

6.5mM

Question 6

Elements of a control centre

Answer 6

-detector
-comparator/control centre
-effectors which make a change such as a muscle contraction

Question 7

Regulated variable

Answer 7

Sensor exists to keep this variable within limits

Question 8

Non regulated variable

Answer 8

Can change to achieve control of regulated variable. Eg Herat rate changing which affects blood pressure

Question 9

Equation for dissociation of co2

Answer 9

Co2 +h20=h202=h+ +hco3-

Question 10

Examples of pyrogens

Answer 10

Eg bacteria

Question 11

Positive feedback mechanism

Answer 11

Amplifies the change eg child birth, the fetus pressing the cervix causes afferent signal to the hypothalamus which caused the secretion of the oxytocin by posterior pituitary causing more contractions.( positive reinforcement|)

Question 12

Feedforward

Answer 12

Limits change
Anticipatory behaviour =acts to minimise disruption to set points

Question 13

What does loss of homeo stasis results in

Answer 13

Disease

Question 14

Negative feedback example

Answer 14

Sensors such as carotid and aortic baroreceptots detect change
Comparator such as brain stem and The nucleus of the tract is solitarius
Effectors such as cardiac or smooth muscle result in vasoconstriction and incresed co which reduces body pressure back to 120/80