Homostasis

Question 1

What is homostasis?

Answer 1

• The ability to maintain a relativly stable enviroment in an ever changing world.

Question 2

what are the three components of control mechanisms?

Answer 2

1- Receptor that moniters the enviroment and responds to change
2-control centre that determines the set point at which the varible is maintained
3-effector which provides the means to repond to stimulus

Question 3

What is negative feedback?

Answer 3

• the output shuts off the original stimulus. Examples of this would be regualtion of glucose or body temp

Question 4

What is positive feedback?

Answer 4

• the output enhances or exagerates the original stimulus, to bring changes to the body. An example of this is breastfeeding

Question 5

What is the normal body tempreture?

Answer 5

• 35.6 to 37.8C

Question 6

What is homostatic imbalance?

Answer 6

• a fluctaution in the ability to maitain equilbruim and a constant envoment within the body.
• An example of this someone may not sweat properly and this would cause them to overheat whcih can lead to hyperthermia/ heatstroke

Question 7

how does ageing effect homeostatic effeciency?

Answer 7

• Loss of neurons/ neurotransmitters = memory loss
• reduced periphral circulation= hypotention, conory heart disease
• decreased bone density
• decreased immunity

Question 8

What is haemostasis?

Answer 8

• the mechanism that leads to the stopping of bleeding from a blood vessel.

Question 9

What are the three stages of haemostasis?

Answer 9

• vascular stage
• Platlet stage
• Coagulation stage

Question 10

what happens in the Vascular stage of hemostasis?

Answer 10

• When a vessel is severed or damaged a vascular spasm occurs. In this, the smooth muscles in the walls of the vessel contract dramatically.

Question 11

what happens in the platlet stage of hemostasis?

Answer 11

• in the second step, platlets bind together when they recognise damaged blood vessels.
• they begin to attach themsleves to endothelial surfaces and expose collogen fibres
• these form a platlet plug which may close the break in the vessel wall

Question 12

What is the coagulation stage in hemostasis?

Answer 12

• this does not start until 30 seconds after injury
• It is when the fibrin network grows, blood cells and more platlets are trapped in the fibroustangle which then forms a blood clot that seal off a portion of the damaged blood vessel