HOMEOSTASIS
Why is it important to maintain blood glucose
If blood glucose conc is too high then water potential of blood = reducedso water molecules diffuse out of cells and into blood by osmosis. This causes the cells to shrivel up and die. If glucose is too low cells= unable to carry out normal activities as theere isnt enough glucose for respiration to provide energy.
what isnt possitive feedback involved in and why
homeostasis because it doesnt keep your internal environment constant
What is the optimum PH
usually 7 but in the stomach its lower
When else can possitive feedback occur
when a homeostatic system breaks down
What is homeostasis
The process by which organisms maintain a relatively stable internal environment.
what do possitive feedback mechanisms do
amplify a change from the normal level, some changes trigger a p. feedback
What does homeostasis involve
control systems that keep your internal environment roughly constant with certain limits
What do homeostatic Systems do
detect a change and respond by negative feedback
What do multiple negative feeback mechanisms do
give more control
Hypethermia and possitive feedback
heat is lost quicker than it can be produced as temp falls brain doesnt work so shiverong stopscausing temp to fall further possitive feedback occurs and takes level further away from the normal level and continues to decrease unless action is taken.
Why is it important to maintain blood PH
if blood ph is too high or low enzymes become dennatured. The H bonds are effected and the 3D shape is changed changing the shape of the active site meaning the enzyme no longer works as a catalyst. Therefore metabollic reactions are less efficient.
Why is it important to maintain body temp
if temp becomes to high enzymes become dennatured. Enzymes molecules vibrate too much and the H bonds that hold their 3D shape break changing the shape of the active site so enzyme can no longer work as a catalyst. Therefore metabollic reactions are less efficient.
What does the homeostatic system involve
receptors a coomunication system and effectors
What are the three key things that are important to maintain
temperature ph and glucose
How does a possitive feedback work
the effector responds to further increase the level away from the normal level
What is negative feedback
the mechanism that restores the level to normal receptors detect whether the levels of something are too high the nervous system or hormonal system send info to the effectors and the effectors respond to counteract the change
Why have multiple negative feedback mechanisms
to actively increase or decrease a level so it returns to normal
Why does homeostasis involve multiple negative feedback mechanisms
to control each thing because more than one mechanism gives more control over the changes in the internal environment
Why is it vital to keep your internal evironment constant
to keep cells functioning normally and to prevent damage
what is possitive feedback useful for
to rapidly activate something e.g a blood clot after an injury
Where does negative feedback work
within certain limits if the change is too big the effectors wont be able to counteract it
What would happen if you only had one negativive feeback mechanism
you could only turn it on or off youd only be able to change a level in one direction so it returns to normal it gives a slower response and less control