Physiology & Health Flashcards
What does sexual reproduction require?
The joining of two gametes.
What are the male gametes in humans?
Sperm.
What are the female gametes in humans?
Ovum/Ova
What are gametes made from?
Germline cells, they can differentiate to make sperm or ova.
What are germline cells?
Cells that can differentiate to become sperm or ova.
What is the function of the testes?
They produce sperm.
What is the function of the sperm duct?
It carries sperm from the testes to the penis.
What is the function of the prostate gland/seminal vesicles?
They secrete fluids which maintain the mobility and viability of sperm.
What is the function of the penis?
Carries sperm out of the body.
What are sperm cells made from?
Germline cells, called sperm mother cells, in the seminiferous tubules.
Where are interstitial cells found?
In between the seminiferous tubules.
What causes puberty to begin?
The hypothalamus produces a releaser hormone.
What effect does the releaser hormone have?
It acts on the pituitary gland and makes it release FSH and ICSH/LH
What does FSH do in males?
It promotes the production of sperm from germline cells in seminiferous tubules.
What does ICSH/LH do in males?
It stimulates the interstitial cells to produce testosterone which acts on the seminal vesicles to stimulate sperm production.
What does testosterone do?
Activates the prostate gland and seminal vesicles to produce their secretions.
What happens if testosterone builds up to a high level?
Negative feedback takes place. It inhibits the production of the two pituitary gland hormones, FSH and ICSH/LH.
What effect does negative feedback have?
It ensures that hormone levels remain more or less constant.
Why are males described as ‘continually fertile’?
They produce sperm from puberty onwards.
What do the ovaries contain?
Immature ova which are surrounded by follicles.
What is the function of follicles?
They protect the ovum and secrete oestrogen.
What is ovulation?
When a mature ovum is released and it enters one of the oviducts.
What does the follicle become after ovulation?
A corpus luteum.
What is a corpus luteum?
Follicles become corpus luteums after ovulation, they produce progesterone.
How long does the menstrual cycle take?
28 days.
What is day 1 of the menstrual cycle?
The first day of menstruation, the start of the period.
What are the two phases of the menstrual cycle?
The follicular phase and the luteal phase.
What happens in the follicular phase?
The follicle develops around an ovum, starting with day 1 and finishing with day 14. FSH is released by the pituitary gland which stimulates the follicle to develop - Follicle Stimulating Hormone. Oestrogen is produced by the follicle. Oestrogen stimulates proliferation of the endometrium and thins the cervical mucus. Low levels of LH are produced until a surge of LH is caused by a peak in Oestrogen. This causes ovulation.
What is FSH’s role in the follicular phase?
It stimulates the development of the follicle around the ovum.
What is Oestrogen’s role in the follicular phase?
It is produced buy the follicle and stimulates proliferation of the endometrium, allowing for implantation of the embryo, and thins the cervical mucus, allowing sperm to pass through more easily.
What is LH’s role in the follicular phase?
It is produced at low levels until a surge in Oestrogen causes a surge in LH, this causes ovulation.
What happens in the luteal phase?
The follicle develops into a corpus luteum which secretes progesterone. Progesterone promotes the vascularisation of the endometrium to prepare it for implantation of the blastocyst.
What is progesterone’s role in the luteal phase?
It is secreted from the corpus luteum and it stimulates the vascularisation of the endometrium to prepare it for implantation of a blastocyst.
What order do the female hormones peak in?
FSH, Oestrogen, LH, Progesterone.
FOLP
When does FSH peak?
During menstruation, when the follicle is developing. Around days 2-4.
When does Oestrogen peak?
Just before ovulation when proliferation of the endometrium is taking place. Around day 12.
When does LH peak?
During ovulation. Around day 14.
When does progesterone peak?
When the corpus luteum is disintegrating. Days 22-24.
What happens if the ovum is fertilised?
It becomes a zygote. Mitosis takes place. It becomes a blastocyst after 4-5 days. It implants in the endometrium and forms a placenta.
What happens if the ovum is not fertilised?
The corpus luteum starts to disintegrate. The levels of the two ovarian hormones start to fall and the endometrium fades away, the women has her period.
What is the negative feedback effect in women?
The pituitary gland produces FSH which causes the follicle to develop. The follicle produces oestrogen and the oestrogen causes the pituitary to stop making FSH and LH.
What happens once the corpus luteum disintegrates?
Oestrogen and progesterone levels fall and the pituitary starts making FSH again.
What is cyclical fertility?
Females have cyclical fertility. They are only fertile for 2 days in every 28 day cycle when the ovum is in the oviduct.
