Homostasis

Question 1

Maintaining balance ( negative feedback )

Answer 1

Homeostasis maintains body’s internal environment within normal limits deposited external changes.

This control is brought about by systems that detect and respond to internal changes. Usually these systems are negative feedback mechanisms.

Question 2

What is positive feedback

Answer 2

Control certain facors such as blood clotting but are less common

Question 3

What is negative feedback ( blood pressure)

Answer 3

Reverse deviations from physiological norms.
If abnormal state is detected such as fall in blood pressure , there is a response to stimulus
The body takes action to correct the imbalance ( raise the blood pressure)

Question 4

Normal blood pressure

Answer 4

1. Receptors detect change and cause decrease heart rate and increase blood vessels diameter
2. Blood pressure decreases towards normal
3. Returns to normal
4. Deviation from normal
5. Blood pressure increase above normal
   ( opposite)

Question 5

What is Body temperature and what is it regulated by

Answer 5

• regulated by negative feedback
  Usally 36-37.5 degrees
  ( regulated by hypothalamus in brain )

Question 6

What is COLD blood and warm blood

Answer 6

Cool blood: hypothalamus sends nerve impulses via the autonomic nervous system to contrict the skin arterioles to prevent heat loss , and to contract strained muscles (shivering) to produce heat.

Hot blood: hypothalamus sends nerve impulses to dilate the skins aterioles, enabling loss of heat, and stimulates sweat glands to increase perspiration,

Question 7

What is heat in body produced by and when does heat loss occur

Answer 7

Heat is produced by
Contractions of staiarted muscle
Metabolic reactions from liver
Peristalsis and chemical reactions in digestive system

Heat loss
- through the skin
In exhaled breath , urine and faeces

Question 8

How is glucose controlled

Answer 8

Mainly controlled By opposing action of two hormones insulin and glycogen witch is made in the pancreas

Question 9

Insulin

Answer 9

Insulin - secreted by islets of langerhans in pancreas, reduces blood glucose levels .
Secretions of insulin is stimulated by an increase of blood glucose level . E.g, when eating meat by

Question 10

Glucogen
What is the normal rate of blood glucose levels

Answer 10

Glucogen increases blood glucose levels . It is secreted in response to low blood glucose and exercise . THE LIVER is the site of action for Glucogen
Usally 3.5-5.5 mmol/liter before meal and
8 mmol/ litre after meal