Hormonal control of reproduction

Question 1

What does ICSH stand for?

Answer 1

Interstitial cell stimulating hormone

Question 2

What are hormones?

Answer 2

Chemical messengers produced by the endocrine glands

Question 3

Where are hormones directly released?

Answer 3

Into the bloodstream and travel to their target tissue or organ where they have their effect

Question 4

What do hormones control?

Answer 4

The onset of puberty, sperm production and the menstrual cycle

Question 5

At puberty what does the hypothalamus in the brain secret?

Answer 5

A releaser hormone that targets the pituitary gland

Question 6

What is the pituitary gland stimulated to release?

Answer 6

One hormone called the follicle stimulating hormone (FSH) and a second hormone called luteinising hormone (LH) in women and interstitial cell stimulating hormone (ICSH) in men. By a releaser hormone produced in the hypothalamus. This triggers the onset of puberty.

Question 7

In males what does FSH promote?

Answer 7

Sperm production in the seminiferous tubules of the testes

Question 8

In males what does ICSH stimulate?

Answer 8

The interstitial cells in the testes to produce the male sex hormone called testosterone

Question 9

What does testosterone stimulate?

Answer 9

Sperm production in the seminiferous tubules and also activates the prostate gland and the seminal vesicles to produce their fluid secretions

Question 10

What happens if there is an overproduction of testosterone

Answer 10

Negative feedback mechanism controls FSH and LCSH

Question 11

What does high levels of testosterone inhibit?

Answer 11

The secretion of FSH and LCSH from the pituitary gland, resulting in a decrease in the production of testosterone by the interstitial cells

Question 12

What do seminiferous tubules unite to form?

Answer 12

Coiled tubes that connect to the sperm duct-free swimming sperm leave the testes in the sperm duct

Question 13

what does semen contain?

Answer 13

Sperm and the fluid from the seminal vesicles and the prostate gland

Question 14

what does seminal vesicles secrete?

Answer 14

A liquid rich in fructose to provide energy for sperm motility

Question 15

What does the seminal vesicles liquid contain?

Answer 15

Hormone like compounds that stimulate contraction of the female reproductive tract

Question 16

What does contractions of the seminal vesicles do?

Answer 16

Help the sperm reach the oviduct (where fertilisation takes place) quicker than ‘swimming’ alone

Question 17

What does the prostate gland secrete?

Answer 17

Lubricating liquid containing enzymes of a thin consistency for the sperm to swim through the oviduct

Question 18

what do the enzymes of the prostate gland do?

Answer 18

Maintain the fluid at optimum viscosity for sperm motility

Question 19

Just before ovulation what do the cells lining the female cervox secret?

Answer 19

Watery mucus

Question 20

What can the watery mucus do?

Answer 20

Be easily penetrated by sperm

Question 21

What does GRH stimulate ?

Answer 21

The pituitary gland

Question 22

What is produced at puberty

Answer 22

Gonad Releasing hormones (GRH)

Question 23

What hormone is produced from the pituitary gland?

Answer 23

FSH/LH (ICSH)

Question 24

After interstitial cells produces testosterone what does is help to do?

Answer 24

Helps FSH to produce sperm

Question 25

What happens if there isn't a constant concentration of testosterone?

Answer 25

The pituitary monitors this to then make ICSH increase or decrease testosterone production

Question 26

When is the hypothalamus stimulated?

Answer 26

When it produces GRH

Question 27

When are males fertile?

Answer 27

All the time

Question 28

Where are interstitial cells found ?

Answer 28

Surrounding the sperm producing tubules of the testes

Question 29

How are sperm formed?

Answer 29

from germline cells in tiny tubes called seminiferous tubules

Question 30

How many days does the menstrual cycle take?

Answer 30

Approximately 28 days with the first day of menstruation regarded as day one of the cycle

Question 31

What pituitary hormones are associated with the menstrual cycle?

Answer 31

FSH and LH and the ovarian hormones oestrogen and progesterone

Question 32

What happens in the follicular phase (first half of the cycle)

Answer 32

FSH stimulates the development and maturation of a follicle surrounding the ovum and the production of the sex hormone oestrogen by the follicle

Question 33

What does oestrogen stimulate?

Answer 33

The repair and vascularisation of the endometrium, thickening it and preparing it for the implant

Question 34

What does high levels of oestrogen stimulate?

Answer 34

The secretion of LH by the pituitary gland

Question 35

What happens in the luteal phase (second stage of the cycle)

Answer 35

A surge in LH triggers ovulation and then stimulates the development of the the corpus luteum from the follicle which secretes progesterone

Question 36

What does LH also stimulate?

Answer 36

The corpus luteum to secrete the sex hormone progesterone

Question 37

What does progesterone promote?

Answer 37

Further development and vascularisation of the endometrium, preparing it for the implantation of a blastocyst, if fertilisation occurs

Question 38

What does high levels of oestrogen and progesterone inhibit?

Answer 38

The secretion of FSH and LH by the pituitary gland, which prevents further follicles from developing

Question 39

What does oestrogen do to the cervical mucus?

Answer 39

It thins the cervical mucus making it more easily penetrated by sperm

Question 40

What does a peak level of oestrogen stimulate?

Answer 40

A surge in the secretion of LH

Question 41

What does the surge in LH trigger?

Answer 41

It triggers ovulation

Question 42

What is ovulation?

Answer 42

The release of an egg (ovum) from a follicle in the ovary

Question 43

When does ovulation occur?

Answer 43

Around mid-point of the menstrual cycle

Question 44

What happens when there's a lack of LH?

Answer 44

A degeneration of the corpus luteum with a subsequent drop in progesterone levels leading to menstruation

Question 45

Give an account of gamete production in the testes

Answer 45

Sperm are produced in the seminiferous tubules Gametes are formed from germline cells Germline cells are formed in the seminiferous tubules of the testes Germline cells divide by mitosis then meiosis to produce sperm Testosterone stimulates sperm production in the seminiferous tubules

Question 46

Give the location of fertilisation in the female reproductive system

Answer 46

Oviduct

Question 47

Where is FSH produced in the body?

Answer 47

The pituitary gland

Question 48

How is the concentration of testosterone in the blood prevented from becoming too high?

Answer 48

As testosterone production increase negative feedback to the pituitary inhibits ICSH production Testosterone concentration decrease and ICSH production increases when testosterone drops

Question 49

What indicates ovulation is likely to occur

Answer 49

Cervical mucus becomes watery and body temperature rises

Question 50

What is an ovum surrounded by as it develops in the ovary

Answer 50

A follicle

Question 51

When there's a peak of oestrogen what starts to increase

Answer 51

progesterone

Question 52

Describe the role of the secretion from the seminal vesicles

Answer 52

Produce fructose for energy Enzymes to thin mucus chemicals to produce contractions of oviduct

Question 53

state an effect of oestrogen on the pituitary gland

Answer 53

stimulates LH production

Question 54

Explain why the rise of ovarian hormones in the blood has a contraceptive effect

Answer 54

Ovarian hormones will inhibit FSH production and so no follicles containing ovules will develop

Question 55

what day does ovulation occur?

Answer 55

Just after a peak of LH which stimulates ovulation

Question 56

State one function of progesterone during early pregnancy?

Answer 56

Vascularisation of the endometrium

Question 57

Describe two ways that the pituitary gland stimulates sperm production in the seminiferous tubules

Answer 57

FSH stimulates sperm production | ICSH stimulates testosterone production. Testosterone then stimulates sperm production

Question 58

What effect does oestrogen have on the uterus between days 4 and 12

Answer 58

proliferation of endometrium

Question 59

What effect does oestrogen have on the pituitary gland on day 12

Answer 59

stimulates LH production

Question 60

How does FSH affect the structure of the follicle

Answer 60

Stimulates follicle development

Question 61

How does lH affect the structure of the corpus luteum

Answer 61

Stimulates progesterone production