Male Reproductive System II PDF

HUMAN PHYSIOLOGY II COURSE CODE: 1601106 3 credit Units Male Reproductive System II Tutors Dr Kasimu Ibrahim Dr Ata Ali  Week 4, Lecture 2 At the end of this lecture, year 2 DDS students should be able to; 1. Describe the endocrine functions of the testes 2...

HUMAN PHYSIOLOGY II COURSE CODE: 1601106 3 credit Units Male Reproductive System II Tutors Dr Kasimu Ibrahim Dr Ata Ali  Week 4, Lecture 2 At the end of this lecture, year 2 DDS students should be able to; 1. Describe the endocrine functions of the testes 2. Describe the semen and its composition 3. Explain male climacteric 8/10/2024 2  gens I melt by a ed mostpotent i ENDOCRINE FUNCTIONS OF TESTIS i Ei he Testis secretes male sex hormones so.me which are collectively called the androgens, that are produced by testes (95%) and adrenal cortex (5%), Including: 4 1. Testosterone I If EEE 2. Dihydrotestosterone 3. Androstenedione Testosterone is secreted in fetal life and adult life test In childhood, practically no testosterone is secreted pay pff At puberty the testosterone secretion starts stonate if becomes almost zero by Ian The secretion starts decreasing after 40 years and the age of 90 years 8/10/2024 it permffqe.gg tesseron 3 spermatogene V9 fetal if 5s tell Functions of Testosterone in Fetal Life I IT III The fetal testes begin to secrete testosterone at about 2nd to 4th month of fetal life under the influence of Human Chorionic Gonadotrophin (hCG). 5580 to Tes 11 a Hypothalamy pinting saw Testosterone performs three functions in fetus 1. Sex differentiation in fetus (Inhibition of Müllerian duct). 2. Development of accessory sex organs and external genitalia. 3. Descent of the testes (the failure cause Cryptorchidism) 8/10/2024 4  adrenalcortex Functions of Testosterone in Adult Life idiodo Testosterone has two important functions in adult: 1. Effect on sex organs Testosterone increases the size of penis, scrotum and the testes after puberty. It is also necessary for spermatogenesis. iq 2. Effect on secondary sexual characters Muscular and bone growth (epiphyseal plates fusion) Shoulder and pelvis bones (Funnel shape pelvis) Skin ( thicker, acne, more melanin) 8 8/10/2024 is 5  I 16 58 Effect on secondary sexual characters (cont.) Hair distribution (pubic, arm pit and facial hair) I Deepening of the voice (thickened vocal cords) Basal metabolic rate (increased) Ear Blood (mild increase RBC count) Electrolyte and water balance (increase ECF by Na and water reabsorption) 8/10/2024 6  To 4,98 8/10/2024 7  i.de vaeror ROLE OF HORMONES IN SPERMATOGENESIS c Spermatogenesis is influenced by many hormones which act either directly or indirectly in The hormones necessary for spermatogenesis are: 1. Follicle-Stimulating hormone (FSH) Responsible for the initiation of spermatogenesis time It binds with Sertoli cells and spermatogonia and induces the proliferation of spermatogonia Stimulates formation of estrogen and androgen binding protein from Sertoli cells 8/10/2024 8  2. Luitinizing Hormone (LH) In males this hormone is called interstitial cell stimulating hormone It is essential for the secretion of testosterone from Leydig cells vi 3. Growth Hormone (GH) Essential for the general metabolic processes in testis g Necessary for proliferation of spermatogonia twitter.iq 4. Testosterone Responsible for sequence of remaining stages in spermatogenesis Responsible for maintenance of spermatogenesis Its activity is largely influenced by androgen binding protein 7 jul 8/10/2024 9  I 2 5. Estrogen It is formed from testosterone in Sertoli cells and necessary for spermiogenesis 6. Inhibin It is secreted by Sertoli cells says 1 Its secretion is stimulated by FSH inhibits FSH secretion through feedback mechanism leading to decrease in the Fs pace of spermatogenesis 7. Activin feedBack Has opposite actions of inhibin and increases secretion of FSH and accelerates spermatogenesis µ 8/10/2024 10  Feedback Control 3 Or sector 1 8/10/2024 11 Semen Organic fluid, also known as seminal fluid, that usually contains spermatozoa (sperm) (consists 10%) with a pH (7.2 – 7.6). i The components of semen come from two sources: sperm, and seminal plasma. Seminal plasma, in turn, is produced by contributions from the seminal vesicle, prostate, and bulbourethral glands The process of discharge semen is called ejaculation. A man usually ejaculates 2-6 mL of semen The seminal plasma provides a nutritive and protective medium for the spermatozoa during their journey through the female reproductive tract. 8/10/2024 12  Prostaglandins in the semen cause thinning of the mucus at the opening of the uterus and stimulate contractions of the uterine muscles, which help move the semen up the uterus. and involved in suppressing an immune response by the female against the foreign semen The alkalinity of the semen helps neutralize the acidic environment of the vagina, protecting the sperm and increasing their motility. Relaxin: enhance motility. Seminalplasmin: antibiotic. i.ir Eetvogaijgfs'semen 8 When first ejaculated, the semen coagulates, making it easier for Yr uterine contractions to move it along; then anticoagulants liquefy the semen, and the sperm begin swimming through the female tract in 8/10/2024 13  MALE CLIMACTERIC 540 b middle age f Male andropause (viropause) or climacteric is the condition in men characterized by emotional and physical changes in the body due to crises low androgen level with aging Testosterone secretion starts declining because of decrease in number and secretory activity of Leydig cells In general if the testosterone level is low at any stage of life, it is called Hypogonadism ( the opposite is Hypergonadism) I s 8/10/2024 14