Biology Questions and Answers

Biology Questions and Answers

gonadotropic hormone that acts upon

the ovariovulation anes of women to stimulated the formation of the (^)
corpus luteum (that secretes estrogen)
and in men upon the testiclesstimulate the production of to
testosterone.

15. What is the relation
    between the thyroid and the
    hypophysis?

The hypophysis secretes TSH, thyroid-
stimulating hhastens the secretion ormone. This hormoneof thyroid
hormones (triiodothyronine and
thyroxine, or T3 and T4).
When the plasma concentration of

thyroid hormones is hiinformation is detected bgh thisy the (^)
hypothalamus and by the hypophysis
and this gsecretion. Wland reduces then the thyroihe TSHd hormone (^)
levels are low the TSH secretion
increases. It is thfeedback. us a negative
Injuries oTSH hyposecretiof the hypophysis that causen (for example, in case (^)
of tissue destruction) or hypersecretion
(in case, e,proliferation or g., of excessivecancer) can cellchange the (^)
functionincompletely.g of the thyroid gland

16. What are some diseases
    caused by abnormal GH
    secretion by the hypophysis?

In childhood deficient GH lead to delayed growth and in severesecretion may

cases to nanism (dwarfism). Excessive

production oexaggerated osseof GH in childrus growth anen may caused

gigantism. In adults GH excess (for

example, people that wrongly ingest GH as ain hypophiseal cancer or in

nutritional supplement) may lead to

acromegaly, edisproportional gxcessiverowth o andf the bone (^)
extremities, like the skull, the
maxillaries, the hands and the feet.

17. What are the target
    tissues and target organs of
    each adenohypophyseal
    hormone?
    GH: bones, cartilages and muscles.
    Prolactin: mammary glacortical portion of the adrenals. TSH:nds. ACTH: the
    thyroid gland. FSH and LH: ovaries and
    testicles.


18. What are the hormones
    secreted by the
    neurohypophysis? What are
    their respective functions?
    The neurohypophysis secretes oxytocin
    and the antidiuretic hormone (ADH).
    Oxytocin is secreted in women during

delivery frequency of to increase the uterine contractionsthe strength and (^)
and thus to help the baby’s birth.
During the lactationsucking action on the moth period the infant’ser’s nipples
stimulatesthat then increases th the production e secretioof oxytocinn of milk (^)
by the mammary glands.
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