(a). Describe the mammalian male urinogenital system (10 marks). (b) Describe the role of each of the following hormones in the human menstrual cycle (i). Oestrogen (3 marks)(ii). Progesterone (3 marks)(iii). Luteinising hormone (3 marks)

(a). Describe the mammalian male urinogenital system (10 marks)

(i). Testes.
-Is a pair of cream-coloured ovoid structures situated in the lower abdomen.
-ln mature mammals they descend into a pair of sacs on either side of the penis, the scrotal sacs/scrotum.
-The testes are connected to the scrotal walls by a tissue called gubernaculum.

Functions of the scrotum
-Suspends the testes outside the body providing a cooler environment for the production and storage of sperms and hormones.
-Protects the testes from external mechanical damage.

(ii). Seminiferous tubules.
-Are several highly coiled tubules, which are the ones that make up the testes.
Function.
-Have actively dividing cells which ultimately give rise to sperms

(iii) Epidydimis
-Is a much coiled tubule, about 1.6 cm long when fully stretched; formed from the union of seminiferous tubules.
-It lies outside and found on the surface of the testes.
Function.
-Storage of sperms;
-Has smooth muscles that contract to force sperms into the vas deferens during ejaculation;

(iv). Sperm ducts/vas deferens/vas deferentia;
-Is a tube which connects the epidydimis to the urethra; the ejaculatory tube.

(v). The urethra.
-ls the ejaculatory duct and is continuous with the urinary bladder and traverse the penis.
-The two vas deferentia (Ieft and right) join and open into the urethral opening i.e. at the junction of the urethra and the urinary bladder.
Function.
-It is urinogenital; since it forms a tube for the passage of urine, and during ejaculation sperms.

(vi). Seminal vesicle.
-is a blinding end sac, which also opens into the urethra at the above junction.
Function.
-Secretes a fluid which forms part of semen into the sperm duct, which provides a favourable medium for the motility/swimming of the sperms.
-Its secretions contain sucrose and prostaglandins
-Sucrose provides a source of energy for the sperm cells;
-Prostaglandins act as a chemical signal in the female system, triggering the rhythmic contraction of smooth muscle along the reproductive tract;

(vii). Prostrate gland.
-It is a tiny gland just below the seminal vesicle. It surrounds the urethra.
Function.
- Secretes a fluid mixture which forms part of the seminal f1uid.
-Its secretes an alkaline buffer that protects sperm cells against the acidic environment of the vagina;

(viii).Cowper’s glands.
-Are also called bulbourethral glands. Function.
-Secretes mucus which lubricates the urethral walls providing a conducive surface for swimming of
sperms.

(ix). The penis.
-Is an erectile intermitted organ through which the urethra passes, and projects from the body. At the tip it has a retractable skin covering called the glans penis.
-It is made up of spongy tissue muscle and blood vessels, which forms the erectile tissue.
Note: -During sexual activity the penis erects by having the spaces in its spongy tissue gouged with blood.
Function;
-It is the male copulatory organ for ejaculation of sperm cells into the female reproductive tract; provides passage for urethra for elimination of urine out of the body;

(b) Describe the role of each of the following hormones in the human menstrual cycle 

(i). Oestrogen (3 marks)

-Healing and repair of the uterine wall following menstruation: stimulates the pituitary glands; to secrete luteinising hormone;

(ii). Progesterone (3 marks)

-Facilitates proliferation (thickening) of the uterine wall and maintains the thickened uterine wall in readiness for implantation; inhibits the pituitary gland from secreting the follicle stimulating hormone and hence no ovulation occurs during pregnancy;

(iii). Luteinising hormone (3 marks)

- Stimulates the mature Graafian follicle to rapture and release the secondary oocyte (ovum) i.e. ovulation; stimulates the remnants of the Graafian follicle to reorganize and transform into corpus luteum; stimulates the corpus luteum to start secreting progesterone;