Human Reproduction Flashcards
What is the role of the testis?
To produce sperm and testosterone.
What is the role of the epididymis?
Matures and stores sperm
What is the role of the sperm duct?
Carries sperm from the epididymis to the urethra.
What are the roles of the seminal vesicles, Cowper’s gland and prostate gland?
-Produce seminal fluid which feeds the sperm and allows them to swim. Sperm and seminal fluid are collectively called semen.
What is the role of the urethra?
Allows the passage of either urine or sperm.
What is the role of the penis?
Places sperm inside the body of a female
What is the role of the scrotum?
Keeps testes at a lower temperature.
What is the optimum temperature for male gamete meiosis?
35 degrees
What is a gonad?
Is an organ that produces sex cells in animals
What is testosterone?
Is the male hormone responsible for the development of primary and secondary sexual characteristics.
What are primary sexual characteristics?
Are the presence of the male and female reproductive parts
What are secondary sexual characteristics?
Refer to features that distinguish males from females, apart from the sex organs themselves.
What are male secondary sexual characteristics?
- Growth of pubic, facial and body hair
- Enlargement of larynx, breaking of voice
- Increased muscular development and bone development
- Growth spurt at puberty
- Increased secretion of sebum in the skin
What does each sperm contain?
- Acrosome
- Nucleus
- Midpiece
- Tail
What is the role of the acrosome in sperm?
Contains enzymes that can digest the membrane of the egg.
What is the role of the ovary?
To produce the egg (ova)
To produce the hormones oestrogen and progesterone
What is the role of the Fallopian tube (oviduct)?
Catches the egg from the ovary and transports it to the uterus.
Where is the site of fertilisation?
Fallopian tube
What is the role of the uterus?
Site of implantation, holds the developing embryo.
Has a lining (endometrium) enriched with blood vessels to nourish the embryo. Forms the placenta
What is the role of the vagina?
Allows entry of sperm and exit of baby at birth.
What are the female hormones?
Oestrogen and progesterone
What does a combination of oestrogen and progesterone cause at the onset of puberty?
Causes the development of the secondary female characteristics
What the are the secondary female characteristics?
- The maturing and enlargement of breasts
- Widening of the pelvis to allow for birth
- The growth of pubic and underarm hair
- A growth spurt
What happens once the meiosis of the egg is complete?
The egg is surrounded in a structure called the Graafian Follicle
What happens when the egg is mature?
The follicle forms a swelling on the outside of the ovary. It bursts at ovulation to release the egg.
What happens to the follicle after ovulation?
Fills with yellow cells and becomes the Corpus Luteum
What hormone does the corpus luteum secrete?
Progesterone
What hormones does the Graafian follicle produce?s
Oestrogen
What is the menstrual cycle?
Is a 28 day sequence of event that produce an egg and prepares the body for pregnancy.
When does the menstrual cycle begin and end?
- Begins at puberty
- Ends with the menopause
What happens through days 1-5 in the menstrual cycle?
- The old lining of the uterus breaks down and is shed from the body.
- A new egg is produced in the ovary by meiosis and this new egg is surrounded by the graafian follicle
What happens through days 6-14 in the menstrual cycle?
- Hormone oestrogen produced by developing graafian follicle
- Hormone has two functions: causes lining of endometrium to build up in preparation for pregnancy
- Prevents the development of any more eggs
What happens on day 14 of the menstrual cycle?
Ovulation
What happens between days 14-28 of the menstrual cycle?
- Graafian follicle develops into corpus luteum.
- Corpus luteum produces progesterone
- Two functions
- Prevents breakdown of endometrium
- Prevents new eggs from forming
What happens by day 22 to the corpus luteum if fertilisation has not taken place?
It breaks down, resulting in a reduction of progesterone levels.
Where is follicle-stimulating hormone (FSH) produced?
The pituitary gland
When is the (FSH) produced?
Between days 1-5 in the menstrual cycle
What is the function of FSH?
- Stimulates a few potential eggs to develop, surrounded by Graafian follicles.
- Each Graafian follicle produces oestrogen, so that FSH can be said to cause the production of oestrogen.
Where is oestrogen produced?
Produced by the graafian follicle in the ovary
When is oestrogen produced?
Between days 5 to 14 in the menstrual cycle
What is the function of oestrogen in the menstrual cycle?
- Causes endometrium to develop
- Inhibits FSH, no more eggs developing
- High levels of oestrogen just before day 14 stimulate the release of the next hormone
Where is luteinising hormone (LH) produced?
Pituitary gland
When is LH produced?
Produced on day 14
What is the function of LH?
Causes ovulation
Causes remains of Graafian follicle to develop in corpus luteum
Where is progesterone produced?
Corpus luteum in the ovary
When is progesterone produced?
Days 14 to 28
What is the function of progesterone?
- Maintains structure of endometrium
- Inhibits production of LSH
- Inhibits production of LH
- Progesterone also prevents contractions of the uterus
What happens by day 28 if no fertilisation has occurred?
- Due to the corpus luteum degrading by day 22, Low leves of progesterone produce the following effects:
- FSH secretion by the pituitary gland- new eggs begin to develop
- Uterus contracts and period starts
What is insemination?
Is the release of sperm into the female.
What is the name of the chemicals that the egg releases to attract sperm?
Chemotaxis
What is fertilisation?
Is the fusion of the egg and sperm nuclei to form a diploid zygote.
How long can the egg survive unfertilised?
2 days
How long can the sperm survive in the female body?
7 days
When is the fertile period?
12-18
Fertilisation may occur between days 7-18 (irregular cycles)
What is implantation?
Is the embedding of the fertilised egg into the lining of the uterus
When does implantation occur?
6-9 days after implantation
