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A Handbook of Biology
Regulate the water (body fluid volume), electrolytic balance,
osmotic pressure and blood pressure. Aldosterone stimulates the
reabsorption of Na+ & water from renal tubules and excretion of
K+ and phosphate ions.
2. MÏÑËRÅLØÇØRTÏÇØÏDS (MÅÏÑLÝ ÅLDØSTËRØÑË):
3. ÅÑDRØGËÑÏÇ ÇØRTÏÇØÏDS:
For growth of axial hair, pubic hair and facial hair during puberty.
Deficiency of corticoid hormones affects carbohydrate metabolism. It
causes acute weakness and fatigue. This condition is called Addison's
disease. (NEET 2020)
B. ÅDRËÑÅL MËDÜLLÅ
Produces
catecholamine
hormones such
as adrenaline
(epinephrine) &
noradrenaline
(norepinephrine).
They are rapidly
secreted in
response to stress
or emergency
situations, thus
called emergency
hormones
(hormones of Fight
or Flight).
These increase alertness,
pupillary dilation,
piloerection (rising of
hairs), sweating, heartbeat,
heart contraction and
respiratory rate. Stimulate
glycogenolysis to increase
glucose in blood. Also
stimulate lipolysis and
proteolysis.
1
2
3
8. PÅÑÇRËÅS (ÏSLËTS ØF LÅÑGËRHÅÑS)
A composite (heterocrine) gland i.e. exocrine + endocrine.
Islets of Langerhans are the endocrine part. There are about 1-2% million
Islets ( 1-2 of pancreatic tissue).
The two main type of cells in the islet of langerhans are α-cell and β-cell.
α-cell and β-cell secrete peptide hormones such as glucagon and
insulin respectively. They maintain glucose homeostasis in blood.
Glucagon: Hyperglycemic factor. It acts on hepatocytes and stimulates
glycogenolysis resulting in an increased blood sugar (hyperglycemia).
Stimulates gluconeogenesis.
(NEET 2020)
Reduces the cellular glucose uptake and utilization.