I know how overwhelming it is to stare at a thick pile of notes and not know where to start. Well, start here. I condensed all of strand 2 into just a few pages (without leaving out any important information). These notes helped me achieve 95% in Life Science for matric and I hope they'll help you ...
endocrine system pancreas
Homeostasis Co-ordination
=maintainence of a constant internal env despite ∆s in the external env Endocrine+Nervous: operate tog to ensure integrated control to mantain homeostasis condition: diabetes mellitus 4. pancreas
what is internal env: immediate surroundings of living cells called tissue [stimulus-> receptor->control centre-> effector(muscle/gland)->response] =chronic disease characterised by high lvls of glucose in the b due to *endocrine(ductless)+exocrine(ducted)
fluid in multicellular orgs undersecretion/problem with insulin [- In SA about 6 mil sudder, 90% adults] 1. exocrine: secretion of pancreatic juice
flows along pancreatic duct into duodenum- helps with chem digestion
how is tissue fluid formed: part of blood(plasma) that leaks out of arterial Hormone 2. endocrine: secretion of hormones by I.L
capillaries due to filtration under pressure into spaces btw cells Type 1: insulin dpndt
a chemical messenger secreted by one endocrine gland or cell into the bloodstream and bcs p not make insulin- glucose remians in b
targeted towards cells in another organ stream instead of moving into cells location Islets of Langerhans(endocrine cells in p)
importance
hormones - alpha cells secrete glucagon
1. mantain internal env of orgs esp higher vertebrates in steady+balc state 1.released from endocrine glands directly into blood
- beta cells secrete insulin
2. establish optimum condition of orgs[conc of water, oxygen...] 2. travel in blood to target organs[affect certain cells, do not last long- broken down
target organ liver(both)+muscles(only insulin)
enzymes]
Feedback mechanisms 3. causes a response ie metabolic reaction
[Response is slower but longer lasting than nervous system] glucose
-> negative
4. hyperactive:Too much of the hormone being secreted -> hypersecretion - simple form of sugar(monosac)
-control mechanism whereby a ∆ from set point of any factor is corrected by
hypoactive: Too little of the hormone being->hyposecretion -soluble- transport in b
bring about a change in the oppdirection back to the normal - fuel for c.r., only enters cells if insulin present
e.g. TSH+thyroxin, insulin+glucagon, pit gland +ovaries, testes
exocrine- secretions carried in ducts where needed e.g. salivary glands, liver, pancreas
endocrine glands do not have ducts+secretions are carried in bloodstream to target org poor management: serious life-threatening implication glycogen
->positive -insoluble polysac
Endocrine glands: vascular, ductless glands that secrete hormones directly into the - short term: large quant dilute urine, extreme thirst, nausea, vomiting, coma
A deviation from norm continues in the same direction - long-term goals: prolong life+prevent complication e.g. blindness, kidney failure, -storage from of glucose in a
bloodstream to reach their target organs.]
ie.continues to get more/ less[not mantain homeostasis instead amplifies amputation of limbs+incr risk of heart attack+stroke
- found abundantly in liver+muscle
responses+processes, moving system further away from starting cond. ] -future cures on horizon- pancreas transplants
e.g. *Contractions during labour, Breast feeding function
control lvl of b glucose in blood[normal btw 3.5 and 5.5 mmol/l of b]
1. receptor: detects c∆ from set point-> control centre, processes Type 2: non-insulin dpnt[insulin resistant]
info+activates corrective mechanism -> effector responds+corrects change
insulin:lowers lvl of glucose in b
- by stimulating glucose to be absorbed from b by cells(esp muscle) makes c.m. more
permeable
.location,hormone,target organ, function , abnormality+symptoms
-be converted into storage form as glycogen in liver+muscles[also to fat- store under skin]
-glycagon raises lvl of glucose in b[ antagonistic effects- opposite]
- by stimulating glycogen stored in liver to break down into glucose
endocrine glands - glucose is released into b+incrs lvl[converts stored fat into glucose]
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