Male Reproductive System

MALE REPRODUCTIVE SYSTEM Reproduction is a process of giving rise to offspring. Male Reproductive System CONSISTS OF 1. Testes (two) 2. several accessory glands 3. a duct system 4. A penis TESTES Secretes spermatozoa and testosterone , which is the male sex hormone .Both testes remain suspended in a pouch called as scrotum which lies outside the abdominal cavity . The temperature of scrotum is little lower then that of normal body temperature which is essential for the production of spermatozoa. THE DUCT SYSTEM It starts with vasa efferentia which arise from the testis and helps in conducting sperm out of the testes. These becomes coiled tube behind the testes called as epididymis , which helps in storing the sperm temporarily. From each epididymis, a partially called vas- deferens ascends into the abdomen, passes over the urinary bladder and receives the duct from seminal vesicles behind the urinary bladder to form an ejaculatory duct. It then passes through the prostate gland and open into urethra. The urethra receives the ducts of the prostate and Cowper's glands and passes through penis to open outside. PENIS It is muscular organ made up of spongy muscular tissue which is used in mating.

ACCESSORY GLANDS These consist of prostate, two seminal vesicles and two Cowper glands. The prostate is present around the urethra. The seminal vesicles are present behind the urinary bladder and their secretion enters the vas- deferens through their ducts. The Cowper's glands are situated behind the urethra into which their ducts open. SEMEN is fluid mixture of spermatozoa and the secretion of the accessory glands. NOTE LEYDIG CELLS secrete testosterone Sertoli cells secrete oestrogen and androgen binding protein. SPERMATOGENESIS Process of formation of mature functional spermatozoa. Spermatogenesis starts at the puberty under influence of of gonadotrophins secreted from the anterior pituitary gland. Seminiferous tubules consist of germinal epithelial cells which undergo first mitotic division and forms primary spermatocyte. The primary spermatocytes then undergo first meiotic division to form secondary spermatocytes. The primary spermatocytes contain 46 chromosomes, which are reduced to 23 by the meiotic division. Secondary spermatocytes again undergo meiotic division. The cells formed are known as spermatids, which after maturation give rise to spermatozoa. In humans, Spermatogenesis takes about 74 days.

Spermatogenesis takes place in Sertoli cells FEED BACK MECHANISM HYPOTHALAMUS ↓ GNRH Anterior pituitary INHIBIN hormone

FSH

LH

interstial cell stimulating

INHIBITIRY EFFECT Leydigs cells secrete

Testosterone inhibitory effect on anterior pit, and hypothalamus Stimulate Spermatogenesis

SEMINAL FLUID FEATURES Contains products of seminiferous tubules Sperm count -- 80 – 100 million/ml Volume 2-3 ml White in colour Componenets Fructose Phosphoryl choline Asdorbic acid Flavins Prostaglandins Sperminine Citric acid Cholesterol Fibrinolysin Zinc Acid phosphatase Bicarbonate Hyaluronidase Fluid part of semen is mainly secreted by prostate and seminal vesicles TESTOSTERONE Source It is synthesized from cholesterol Site Leydig cells of testis Stimulated by LH Mechanism of action

Converted inside the cells into dihydrotestostreone (DHT) which is more potetnt then testosterone

ACTIONS 1. For Spermatogenesis 2. Development of secondary sexual characters and accessory sex organs 3. Anabolic effect. i. Retention of calcium ,phosphorous, sodium , potassium,water ii. Needed for growth iii. Nitrogen retention