Animal Hormones Flashcards

All 15 cards in this deck

Which endocrine gland is situated in the head, attached to the brain?

The pituitary gland.
The thyroid gland is in the neck; the pancreas and adrenal glands are in the abdomen.

Which endocrine gland produces insulin, and what are its target organs?

The pancreas; its target organs are the liver and muscles.

True or false? Hormones are carried from endocrine glands to their target organs by red blood cells.

False. Hormones are transported dissolved in the blood plasma.

What happens during menstruation (around days 1–5 of the menstrual cycle)?

The lining of the uterus breaks down and is lost through the vagina.

What happens at ovulation, around day 14 of the menstrual cycle?

An egg (ovum) is released from a follicle in the ovary.

What is the role of oestrogen in the menstrual cycle?

It makes the uterus lining repair and thicken after menstruation.
Oestrogen is produced in the ovaries.

State two effects of progesterone on the uterus lining.

The lining is maintained/thickened, and the number and size of its blood vessels increase, preparing it for an ovum to implant.

True or false? The contraceptive pill protects the user against sexually transmitted infections (STIs).

False. Only barrier methods such as the condom give protection from STIs.

Give two ways that hormonal contraception, such as the pill, prevents pregnancy.

It prevents ovulation, and it thickens the mucus so sperm cannot reach or fertilise the ovum.
The pill contains oestrogen and/or progesterone.

How does a barrier method such as a condom prevent pregnancy?

It stops the sperm reaching the ovum, so fertilisation cannot happen.

Give one advantage and one disadvantage of using a condom as a method of contraception.

Advantage: gives protection from STIs (also non-prescription, easy to use, does not affect fertility).
Disadvantage: can split (also less effective past its use-by date, latex allergy, reduced sensitivity).

What is a hormone?

A chemical messenger, made by an endocrine gland, that is carried in the blood plasma to its target organs.

Which hormone do the testes produce?

Testosterone. It controls male development at puberty and the production of sperm.

What happens to the uterus lining when the level of progesterone falls?

It breaks down and is lost, so menstruation begins.

Give one advantage of hormonal contraception compared with barrier methods.

Either: when used correctly it is more effective at preventing pregnancy; or nothing needs to be done at the time of sex.