Homeostasis Flashcards
Define homeostasis
The maintenance of ideal or optimal conditions in the body
To maintain homeostasis there has to be some means of monitoring to detect any deviation from the optimum and allowing for correction
This is done through effectors and feedback mechanisms
What are some of the ways we can monitor homeostasis?
pulse rate
BP
body temperature
respiratory rate
what is negative feedback?
A reaction that causes a decrease in function. It occurs in response to some kind of stimulus. Often it causes the output of a system to be lessened, so the feedback tends to stabilize the system. This is homeostasis
What is negative feedback in terms of glucose, insulin and glycogen?
the glucose norm- glucose increase- pancreas receptors-(more insulin) liver-glucose>glycogen- glucose norm
NO DEVIATION
the glucose norm- glucose decrease-pancreas receptors (more glucagon (a hormone formed in the pancreas which promotes the breakdown of glycogen to glucose in the liver))-liver-glycogen(liver storage version)>glucose- glucose norm
How is glucose regulated?
Within the pancreas and the cells that produce the pancreatic fluid (including digestive enzymes), are special groups of cells- the islets of Langerhans which contain two types of cell that produce the hormones insulin and glucagon
These islet cells detect rises in blood glucose levels and release insulin. This enables cells to take up glucose from the blood so it drops the level again
Within the muscle and liver cells, the absorbed glucose is built up by specific enzymes into a carbohydrates storage molecule called glycogen
The resulting decrease in blood sugar level is monitored by the pancreas and insulin production reduces and stops
if as a result of normal metabolism and cellular respiration glucose levels drop, the islet cells again detect this change but this time releases glucagon, which enters the liver and muscle cells and activates enzymes that break glycogen back down into glucose, which exits cells and raises blood sugar levels again
upon detecting the rise, the pancreas stops the production of glucagon
what happens when there is too much or too little glucose?
too little glucose = fainting, coma and death
too much or widely fluctuating levels results in glucose being lost in the urine and damage to blood vessels, leading to heart and kidney disease, blindness, strokes and amputations as a result of tissue damage, especially in the limbs.
