Biology Questions and Answers
- Where are the adrenal
glands located? How many are
they and what are their
portions?
Each adrof each kidenal gland is located oney (forming a hat-liken the top
structure two glands. The adrenal parenchymalfor the kidneys), so there are
structure is divided into two portions:
the most pportion, or adrenal cortex, aneripheral is the corticald the (^)
central is the medullary portion, or
adrenal medulla.
- What are the hormones
secreted by the adrenal
medulla? What are their
respective functions?
The medullary portion of the adrenals
secretes hormones of the catecholaminegroup: adrenaline (also known as
epinephrine) and noradrenaline (also
known as norepinephrine). Besidhormonal function, adrenaline andes their
noradrenaline act as neurotransmitters
too. The neurons that usneurotransmitters are called e them asadrenergic (^)
neurons.
Adrenaline ibreaking into glucose (glyconcreases the glycogenolysis)gen (^)
thus increasinmetabolic rate of the body. Adrenalineg glycemia and the basal
and noradrenaline are released during
situations of response) and they intensify thdanger (fightfight or e flight
strength and rate of the heartbeat andselectively modulate the blood irrigation (^)
in some tissues by selective vasodilation
and selectivevasodilation they increase th vasoconstriction.e blood By (^)
supply to the brain, the muscles and the
heart anreduce the blood supply to thd by vasoconstrictione kidneys, they (^)
the skin and the gastrointestinal tract.
Substancesnoradrenaline that p like adrenaline aromote vasodilationnd (^)
or vasoconstrictionsubstances. are called vasoactive
- What are the hormones
secreted by the adrenal
cortex? What are their
respective functions?
The corticalsecretes hormones of the corticoid portion of the adrenals (or (^)
corticosteroid) group, derived from
cholesterol: gmineralocorticoidslucocorticoid, and cortical (^) sex
hormones.
The glucocorticoids arcortisone. The glucocorticoidse cortisol stimulate and (^)
the formation odegradation of proteins of the musclef glucose from the (^)
tissue (help to increase glycemia. Tgluconeogenesis) and so thhese ey
hormones play an important
immunosuppressantreduce the action of the immu role, i.e., theyne system (^)
and for this reason they are used as
medicine autoimmunto treat ine diseases and rejection oflammatory and (^) f
transplanted organs.
The mineralocorticoidsdeoxycorticosterone regulate the aldosteron e and
sodium aconcentration and potassiumnd thus they control th blood (^) e
water level of the extracellular space.
Aldosteronresorption e increases the sodiumand thus the water resor (^) ption
in the renal tubules and it also
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