Azantee Yazmie Abdul WahabDept. of Obstetrics & GynaecologyKulliyyah of MedicineIIUM Kuantan

Adolescence Puberty Burst of hormones activate maturation of the gonads: testesBegins: 9 14 yrs of age

PubertyPhases of growth between childhood and adulthoodDefined as the period when endocrine and gametogenic functions of the gonads have first developed to a point where reproduction is possible

General physical changes Enlargement of the external and internal genitaliaVoice changesHair growthMental changes Changes in body conformation and skinSebaceous gland secretions thicken/increase acne

Puberty Phases or stages are :- 1. Pre adolescent stage (7.5 yrs) 2. Genital development begins(12yrs) 3. Axillary and pubic hair start appearing also enlargement of penis is there(14yrs) 4. Further growth of testis,penis and genitalia and sudden increase in height spurt(15yrs) 5. Adult genitalia and secondary sexual characters(16.5yrs)

Delayed or absent pubertyThe normal variation in the age at which adolescent changes occur is so wide that puberty cannot be considered to be pathologically delayed until the menarche has failed to occur by the age of 17 or testicular development by the age of 20. Causes can be:-1. Failure of hypothalamus to secrete gonadotrophins 2. Primary gonadal failure kleinfelters syndrome and turners syndrome 3. Deficiency of enzymes for steroid synthesis 4. Deficiency of specific receptors in the target tissues

Hormones: Testosterone- essential for growth of germinal testicular cellsLuteinizing hormone - stimulates the Leydig cells to secrete testosterone. Follicle-stimulating hormone -for conversion of the spermatids to sperm (the process of spermiogenesis). Estrogens essential for spermiogenesis. Growth hormone (as well as most of the other body hormones) is necessary for controlling background metabolic functions of the testes.

Endocrine RegulationNegative feedback:Inhibits GnRH from hypothalamus.Inhibits anterior pituitary response to GnRH.Inhibin secretion inhibits anterior pituitary release of FSH.Female: Estrogen and progesterone.Male: Testosterone.

Androgen hormones TestosteroneDihydrotestosterone

Effect on androgen hormones:Prenatal development- testosterone stimulate male reproductive system ducts & descent of testis - DHT stimulate development of external genitals Development of male sexual characteristic- puberty: testosterone & DHT develop & enlargement of male sex organs & masculine secondary sexual characteristic Development of sexual function- male sexual behavior, spermatogenesis & libido

TestosteroneInterstitial Cells of Leydig in the TestesThe concentration of estrogens in the fluid of the seminiferous tubules is quite high and probably plays an important role in Spermiogenesis. This estrogen is believed to be formed by the Sertoli cells by converting testosterone to estradiol

Control of testosterone secretionNegative feedback:Testosterone inhibits LH and GnRH production.Maintain relatively constant secretion of LH and FSH.Declines gradually in men over 50 years of age.Testosterone converted to DHT, which inhibits LH.Inhibin inhibits FSH secretion

TESTOSTERONE - FUNCTIONS1. INITIATION & MAINTAINANCE OF SPERMATOGENESIS.2. GnRH FROM THE HYPOTHALAMUS3. INHIBITS LH SECRETION VIA ANTERIOR PITUITARY.4. DIFFERENTIATION & MAINTAINANCE OF MALE SEXUAL CHARACTERISTICS5. INDUCES DIFFERENTIATION & MAINTAINS ACCESSORY REPRODUCTIVE ORGANS.6. STIMULATES PROTEIN ANABOLISM, BONE GROWTH & ITS CESSATION.7. ENHANCES LIBIDO & AGGRESSIVE MASCULIN BEHAVIOUR

Hypogonadismdue to absent or deficient testicular functionsCongenital nonfunctioning of testisUnderdeveloped testis due to absence of HCG in fetal lifeAbsence of androgen receptors in testis

HypergonadismDue to excessive secretion of male sex hormones as in tumors of Leydig cells.Features:- rapid growth of musculature and bones - height is less due to early closure of epiphysis - excessive development of sexual characters - secrete estrogens which causes gynaecomastia

Testicular temperatureSpermatogenesis requires a temperature considerably lower than that of the interior of the body. The testes are normally maintained at a temperature of about 32 C. High temp stops spermatogenesis and increases cancer risk

Spermatogenesis

Spermiogenesis Maturation of spermatozoa. Phagocytosis of cytoplasm by the Sertoli cells.Cytoplasm is eliminated.

Spermatid undergo change in shape and orientation of organelles:- a) nucleus undergo condensation and forms head.b) golgi apparatus forms the acrosome c) mitochondria forms the tail part provide energy for movement

Sperm movement Back-and-forth movement of the tail (flagellar movement) provides motility for the sperm. This movement results from a rhythmical longitudinal. The energy for this process is supplied in the form of adenosine triphosphate that is synthesized by the mitochondria in the body of the tail.

Normal sperm move in a fluid medium at a velocity of 1 to 4 mm/min.