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What is homeostasis?
it is a constant maintenance of internal environment, with the activation of corrective mechanisms to return a parameter towards its reference point. This is to regulate and hence self-regulating and it is also controlled by negative feedback mechanism.
what is endocrine system?
A physiologically inter connected system and endocrine gland which are ductless and secrete hormones directly into the bloodstream to affect target cells to carry out.
what is hormones?
specific chemical substances produced by endocrine glands and are transported to the blood, to other tissues [ target cells] where they exert a specific regulatory effect on the body. only target cells will have receptors sites for the hormones.
increase in e blood conc is detected by beta-cells of islets of Langerhands
Insulin: decrease in the blood glucose conc.
1) increase in the rate of absorption of glucose.
- binds to the receptor
- triggers the vescles containing glucose transporters to fuse with plasma mbm
- inserting glucose transporters to plasma mbm.
- permeability of liver and muscle cells increases
- more glucose will be taken up
2) increase in the conversion of glucose to glycogen
-activate glycogen synthase in liver and muscle
- to synthesize glycogen from glucose
- decreases the breakdown of glycogen
3) increase in the rate of use of glucose in cell metabolism
- speed up kreb cycle and glycolysis in e liver and muscle cells
- to produce ATP
4) Increasing e rate of fats synthesis
-liver capable in sotring glycogen up to 5 %
-more glucose are then shunted from entering into liver cells
- leading to synthesis of fatty acids
- used by adipose to synthesis triglycerides for storage
-also facilitate the entry of glucose into adipose tissues, which are then used to make glycerol.
- glycerol + fatty acids ----> triglycerides
- promote accumulation of fats in adipose tissue
- inhibits lipolysis
alpha cells of islets of langerhands detect low blood conc.
- glucagon which is pre-synthesized and stored in vesicles is released out of alpha cell via exocytosis into blood circulation.
help to increase in the blood glucose level
1) stimulate the breakdown of glycogen into glucose
-only in liver
2)activate hepatic gluconeogenesis
-stimulate the breakdown of proteins and fats in the liver
- den converted into glucose
3) stimulate lipolysis of triglyceride in adipose tissue
conserving glucose by providing fatty acids to respire.
importance
1) glucose is the main respiratory substrate. ( source of energy)
2) brain and nervous sys can only metoblise glucose
3) will cause cells to lose water by exosmosis
4) conc of blood glucose affects water potential in da vody
- low amt of glucose is reabsorbed into kidneys
- excessive glucose will present in the renal filtrate
destruction of beta cells
-hyperglycemia [ high blod sugar]
-glycosuria [ glucose in urine]
-diuresis [ diluted urine, dehydration of body]
dietary therapy!! TREATMENT (=
