Reproductive System Flashcards
What are the ovaries?
Where the egg is produced in the process of oogenesis. The outer layer of the ovaries produces primary oocytes and follicle cells surrounding it called a primary follicle. Follicle cells form a wall many cells thick and fluid collects inside it to make a Graafian follicle. The mature follicle forms a blister on the surface of the oocyte is released. After puberty one primary follicle develops a month.
What are the oviducts?
Extends from the ovaries to the uterus. They are fringed with fimbriae. The lining of them is ciliated
and muscular and the movements of the cilia and the muscles move the oocyte towards the uterus. Fertilisation takes place in the Fallopian tubes.
What is the uterus?
Where the fertilised egg develops. It has the endometrium, inner layer rich in blood vessels, and the myometrium, the middle layer composed of smooth muscle. The endometrium builds a lining periodically which is shed if no fertilisation occurs. The function is to carry the foetus through pregnancy.
What is the cervix?
The lower portion of the uterus which forms the neck of the uterus and opens into the vagina. The narrow opening of the cervix is called the os which allows menstrual blood to flow out. During pregnancy it closes to keep the foetus in. It also dilates during labour to allow the foetus out. It is covered by epithelium (squamous or columnar).
What is the vagina?
A muscular tube containing elastic tissue and a folded lining so it can enlarge. It is the birth canal. The epithelium lining the vagina secretes an acidic fluid preventing the growth of harmful organisms.
What are the testes?
Composed or many seminiferous tubules which are tightly coiled tubes where spermatogenesis occurs. It takes place fro the outer layer of tubules, the germinal epithelium, towards the centre of the tube where sperm break away and move to the epididymis. Between the tubules are connective tissue, blood vessels and instertitial cells/cells of Leydig which secrete testosterone. Testosterone enters the seminiferous tubules in the testes and stimulates cells associated with spermatogenesis.
What is the epididymis?
Coiled tube at the posterior of the testis. It’s function is storage, maturation and transport of sperm. It connect the ducts of the testis to the vas deferens. Some fluid is reabsorbed making sperm more concentrate. The sperm become mobile here.
What is the prostate gland?
A compound wrapped around the urethra and placed just below the bladder, secreting alkaline fluid to neutralise the acidity of the vagina, forming parts of the seminal fluid.
What are the seminal vesicles?
Glands formed as pockets in the walls of the vas deferens. The fluid in the seminal vesicles is the seminal fluid which is alkaline and contains proteins, enzymes, fructose for energy and mucus.
What is the vas deferens?
Tubes carrying sperm from the testis to the urethra. Each tube has smooth muscle which contracts to move sperm forward.
What is the urethra?
Runs from the bladder to the end of the penis. Carries urine and sperm out.
What is the penis?
Has an internal structure of erectile tissue composed of a number of blood spaces separated by sheets of connective tissue. The penis contains the urethra. It introduces semen into the vagina and is the route of urine.
What does FSH and LH do?
FSH = made by the pituitary gland, stimulates follicle growth LH = produces by the pituitary gland and causes ovulation
What does oestrogen and progesterone do?
Oestrogen is produced by follicle cells and causes a build up of endometrium.
Progesterone is produced by the corpus luteum and maintains the endometrium.
Describe the menstrual cycle.
FSH causes an egg and follicle to mature - oestrogen is released - oestrogen inhibits FSH and builds up the endometrium making it more vascular - stimulates LH - causes ovulation - leaves the Graafian follicle which degenerates into the corpus luteum - releases progesterone - maintains the endometrium - if no egg is fertilised the CL breaks down and progesterone stops - endometrium breaks down.
Describe fertilisation.
Sperm are deposited at the top of the vagina near the cervix (most leak out). The cervix is blocked by mucus and this is only thin enough to allow the passage of sperm during the first part of the menstrual cycle. The movement of the sperm to the oviducts are due to the tails and the cilia of the tubes. Fertilisation takes place in the oviducts. Many sperm surround the ovum and penetrate the outer layers which are made of follicle cells. Sperm must undergo the acrosome reaction to get into the egg where enzymes are released, allowing the sperm in. The sperm nucleus and the ovum nucleus fuse.
