Reproduction

Question 1

Semineferous tubules

Answer 1

produce gametes called sperm. To do this, the tubules have specialised germline cells which can carry out meiosis – a special form of cell division that produces gametes only.

Question 2

Interstitial cells

Answer 2

Are found in the area between the semineferous tubules in the testes and they produce a male sex hormone called testosterone

Question 3

Glands found in reproductive system and function

Answer 3

The prostate gland and seminal vesicles secrete fluids that maintain the mobility and viability of the sperm.These fluids along with sperm, make up liquid called semen

Question 4

Name main structures of the Female Reproductive System

Answer 4

Uterus
Endometrium
Ovary
Vagina
Cervix

Question 5

Ovaries

Answer 5

-Contain immature ova(egg cell)
-Various stages of development
-Each ovum is surrounded by a follicle that protects it whilst it is developing
-follicle secretes hormones
-many stages in maturation of each ova
-Mature ova are released into the oviduct where they may be fertilised by sperm to form a zygote
-if fertilisation does not take place, the ovum will be shed along with the endometrium and the time of the women’s period

Question 6

Target Tissues

Answer 6

Each hormone has a specific target tissue which means when a hormone reaches a specific target tissue, it brings about a specific effect

Question 7

Hypothalamulus

Answer 7

A gland found in the brain and produces a hormone called release hormone which triggers onset of puberty

Question 8

Releaser hormone stimulates the pituitary gland to release which hormones

Answer 8

Follicle stimulating hormone(FSH)
Interstitial cell stimulating hormone(ICSH)

Question 9

FSH in males

Answer 9

-promotes sperm production in the semineferous tubules
-FSH is a pituitary hormone

Question 10

ICSH

Answer 10

-stimulates the interstitial cells to produce testosterone
-ICSH is a pituitary hormone

Question 11

Testosterone

Answer 11

-male sex hormone
-produced by interstitial cells in the testes
-stimulate sperm production same as FSH
-also activates the prostate gland and seminal vesicles to produce their secretions

Question 12

Negative Feedback Control of Testosterone by FSH and ICSH

Answer 12

As the concentration of testosterone builds up in the bloodstream, it reaches a level whereby it inhibits the secretion of FSH and ICSH by the pituitary gland.

This leads to a decrease in testosterone concentration.

As testosterone concentration decreases, inhibition of the pituitary gland slows and both FSH and ICSH production increases again.

This type of self-regulating mechanism is called negative feedback

Question 13

Hypothalamus in females

Answer 13

This gland also produces a hormone called releaser hormone in females which triggers the onset of puberty

Question 14

Releaser hormone stimulates the pituitary gland to release 2 hormones in females:

Answer 14

-Follicle stimulating hormone(FSH)
=Luitenising hormone(LH)

Question 15

Menstrual Cycle

Answer 15

-the menstrual cycle begins in females at puberty. An average cycle takes approximately 28 days with the first day of menstruation regarded as day one of the cycle
-2 phases=
The Follicular Phase
The Luteal Phase

Question 16

Follicular Phase(1-14 days)

Answer 16

-The pituitary gland is the site of production for FSH(pituitary gland)
-FSH stimulates the development of a follicle
-Oestrogen is produced by tissues in the ovaries
-Oestrogen stimulates the proliferation of the endometrium preparing it for implantation
-it makes cervical mucus thinner making it more easily penetrated by sperm
-Peak levels of estrogen stimulate a surge in the secretion of a hormone called LH

Question 17

Ovulation(around day 14)

Answer 17

-Ovulation is a process where an egg is release from a follicle in the ovary. It usually occurs around the mid-point of the menstrual cycle.
-LH(pituitary hormone) is produced by pituitary gland
-Peak levels of estrogen stimulate a “surge” in the secretion of LH
-This surge in LH is the direct cause of ovulation as it cause the blister-like wall of the follicle to rupture and release the egg.

Question 18

The Luteal Phase(around DAY 14-28)

Answer 18

-LH stimulates the follicle to develop in a corpus luteum(ovulation occurs)
-The structure secretes the hormone progesterone(some oestrogen also continues to be released)
-Progesterone(an ovarian hormone) promotes further development and vascularisation of the endometrium preparing it for implantation if fertilisation occurs

Question 19

Negative feedback effect of ovarian hormones

Answer 19

These hormones inhibit the pituitary gland in the following manner: -

1. High levels of oestrogen reducesthe secretion of FSH preventing further follicles from developing.
2. High levels of progesterone reduces the secretion of LH which leads to degeneration of the corpus luteum with a subsequent drop in progesterone levels leading to menstruation.

Finally, when menstruation begins this indicates that the next cycle has now begun!