Reproductive System. Male Reproductive Physiology . DR. ZAHOOR ALI DR. AMEL EASSAWI. Objectives. Describe the physiological functions of the major components of the male reproductive system.
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Male Reproductive Physiology
DR. ZAHOOR ALI
DR. AMEL EASSAWI
Primary Sex Organs: Testes
Exocrine Function (spermatogenesis)
Endocrine Function: Leydigcells (interstitial cells). Androgen Secretion (mainly testosterone)
PRODUCTION RATE (mg/day)
300TOTAL ANDROGEN PLASMA LEVELS AND PRODUCTION RATES IN MEN
Small amount produce by adrenal cortex
A portion of the testosterone secreted by the testes is converted to estrogen outside the testes by the enzyme aromatase, which is widely distributed but most abundant in adipose tissue
Testosterone serves as a prohormone for some activities
Three major stages
1. Complex process by which diploid primordial germ cells (spermatogonia) are converted into motile haploid spermatozoa (sperm).
2. It takes 64 days for development of mature sperm from spermatogonium (several hundred million sperm may reach maturity daily)
Spermatogenesis: Spermatids to Sperm
Consists of four parts
descent of testes is incomplete, testes remain in the abdomen.
1. Bilateral: Impaired Testosterone secretion and spermatogenesis.
2. Unilateral :Normal Testosterone and impaired spermatogenesis.
2. 5Reductase Deficiency
1. True Precocious Puberty
Premature activation of hypothalamic-pituitary axis. Early virilization and spermatogenesis.
Leydigcell tumors (a rare condition) leads to precocious pseudopuberty in prepubertal boys. Premature virilization without spermatogenesis.
3. Feminizing States
4. Delayed or Deficient Puberty
1. Isolated Gonadotropin deficiency(KALLMANN SYNDROME)
2. CNS disorders.
3. Testicular diseases.
1. Infertility Under androgenization
Panhypopituitarism, Cushing disease, Hyper-prolactinemia.
2. Testicular disorders
47, XXY – CLASSIC FORM
46, XY – MOSAIC FORMS
48, XXYY, 48XXXY – VARIETY OF MOSAIC FORMS
HIGHER FREQUENCY SYNDROMES
3. Acquired Defects
1. Viral Orchiditis
2. Trauma (Physical and Temperature)
3. Drugs (Alcohol, Marijuana)
4. Systemic diseases (Liver, Renal, Sickle Cell)
2. Infertility with Normal Virilization
1. Hypothalamic-Pituitary disorders
2. Testicular disorders
*Varicocele, Immotile Cilia Syndrome, Germinal Cell Aplasia
3. Acquired defects
4. Systemic diseases
5. Impaired sperm Transport
* HIGHER FREQUENCY SYNDROMES
Erectile dysfunction or Impotence:
Failure to achieve or maintain an erection suitable for sexual intercourse. Affect 50% of men between 40 and 70 years old. May be due to:
1. Psychological factors.
2. Physical factors.
A. Nerve damage
B. Medication that interfere with autonomic function
C. Problem with blood flow to the penis.
Sildenafil (Vigra): prescribed to treat erectile dysfunction. It does not produce an erection but it amplifies and prolongs an erectile response triggered by usual means of stimulation.