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16 terms

Lecture 38: Reproductive systems: Male A&P

Seminal vesicles
--- ---:
Contribute 60% semen volume
-Viscous seminal fluid
-Fructose (provides energy)
-Prostaglandins (Aid sperm transport)
-Fibrinogen (Aids coagulation of sperm in female reproductive tract)
--- ---:
Contributes 30% semen volume
-Thin seminal fluid
-slightly acidic pH (citric acid used by sperm for ATP production)
-Proteolytic enzymes (breakdown clotting proteins)
-Plasmin (Antibiotic destroys bacteria)
Bulbourethral gland
--- (Cowper's) ---:
Mucous-like fluid (lubricant that minimizes damage to sperm)
Alkaline (protects sperm from acids in urine)
Testis and --- of sperm:
Seminiferous tubules
Straight tubules
Rete testis
Efferent Ducts
Ductus epididymis
Ductus (vas) deferens
conversion of undifferentiated germ cells (spermatogonia) into specialized, motile sperm (spermatozoa)
1 spermatocyte
2 spermatocyte
Sperm cell
Sertoli cells
-Nurse cells
Support sperm production
Support sperm development within densely packed seminiferous tubules
-Columnar with adjoining lateral
-Extend from basal lamina to lumen
Leydig Cells
-Testosterone producing portion of testis
-Located in connective (interstitial) tissue
-Between loops of seminiferous tubules
-"Spermatogonia" serve as stem cells
-During mitosis one remains a spermatogonium while the other gets ready for meiosis and subsequent differentiation of spermatozoa
-Meiosis involves 2 rounds of cell division
-Chromosome number is halved
-4 spermatids result from meiosis
-Differentiate into sperm cells spermatozoa
Differentiation and packaging: ---
-Morphological changes allow motility and protection of chromosomes against environmental change
-Spermiation is release of mature spermatozoa into lumen of seminiferous tubule
-Capacitation or final maturation of the sperm occurs within female reproductive tract
Sperm motility defects due to loss of "CATSPER" channel. CATSPER proteins are expressed in the principal piece of the sperm flagellum (box). Sperm deficient for CATSPER channels can move through the extracellular matrix (ECM) of the oocyte but cannot penetrate due to failure to achieve Ca2+ dependent hyperactivated motility
Anterior pituitary
--- --- synthesizes hormones (LH and FSH) that modulate activity of sertoli and leydig cells
Luteinizing Hormone
stimulates testosterone production by leydig cells
Follicle stimulating hormone
stimulates production of sperm in conjunction with testosterone by regulating activity of sertoli cells
"Summary" hormonal regulation of male reproductive function
Sertoli cells stimulated by FSH and testosterone release androgen binding protein which binds testosterone; thereby increasing testosterone concentration within the seminiferous tubules and stimulating spermatogenesis
Inhibin Hormone
--When sperm production is sufficient
-sertoli cells release inhibin
-inhibits FSH secretion by the anterior pituitary
-decreases sperm production
--When Sperm production is proceeding too slowly
-less inhibin is released by the sertoli cells
-more FSH will be secreted
-Sperm production will be increased
gene expression
-Testosterone and dihydrotestosterone bind to receptors in cell nucleus to alter --- ---
-During prenatal development this leads to the differentiation of male structures
-At puberty, these hormones cause development of secondary sexual characteristics and maturation of the adult reproductive system
-sexual behavior and libido
-male metabolism (bone and muscle mass heavier)
-deepening of the voice