Male reproductive system
- Created by: Saoirse
- Created on: 22-12-14 11:15
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- Male reproductive system
- Internal anatomy of penis
- parasympathetic fibres from sacral portion of spinal cord initiate and maintain erection
- Release and stimulate local production of NO - nitric oxide
- NO relaxes smooth muscle of arterioles in erectile tissue
- Relaxation of blood vessel = increased blood flow = erection of penis
- Spermatogenesis
- Process of spermatozoa (mature gamete) production
- Occurs in seminiferous tubes - proceeds from outer layer to lumen
- Involves: mitosis, meiosis, spermiogenesis
- Spermatogonia develop from primordial germ cells during week 5 of development
- Spermiogenesis - formantion of acrosome, development of flagella and multiplication of mitochondria
- Sperm are haploid (n), unable to swim at this point and incapable of fertilisation
- Anatomy of spermatozoon
- lacks many organelles - reduces size/mass, increasing mobility and speed
- 4 distinct regions
- Head: densely packed chromosomes, acrosome contains enzymes for fertilisation
- Neck: centrioles and original spermatid
- Middle piece: mitochondria
- Tail: flagellum
- Becoming fully functional
- Epididymis
- Cilia in efferent ductules move immobile spermatozoa into epididymis
- Has a head body and tail bound to posterior region of each teste
- Spermatozoa mainly stored in tail
- Site of sperm functional maturation
- Peristaltic contractions of smooth muscle and moving fluid transports spermatozoa along epididymis to ductus deferens
- Ductus deferens
- transport and storage of spermatozoa
- Epididymis
- Anatomy
- Testes
- Spermatic cord: muscle enclosing ductus deferens, blood vessels, nerves and lymphatic system supplying testes
- Cremaster and dartos muscles: allow accent/descent of testes
- Rafe: raised thickening of scrotum, externally divides 2 testes
- Histology
- Septa subdivide into 200-300 lobules
- each lobule contains 1-3 seminiferous tubules
- interstitial (leydig) cells between tubules produce androgens
- Septa subdivide into 200-300 lobules
- Seminiferous tubules
- Site of spermatogenesis
- Spermatogenic cells: spem forming cells
- Sertoli cells: support spermatogenesis
- Nurture and provide structural support for sperm during development
- Roles
- phagocytosis of degenerated germ cells
- promotion of mitosis and meiosis (stimulated by FSH and testosterone)
- Blood-testes barrier- controls composition of fluid in tubule by regulating transport from blood
- produce inhibin and androgen binding protein (ABP)
- Seminal vesicles (glands)
- Active secretory glands = 60% semen vol
- Alkaline secretion to neutralise acids
- High conc of fructose
- Prostaglandins: stimulate smooth muscle contraction
- Fibrinogen: formation of temporary semen clot upon ***********
- Prostate gland
- Prostatic fluid (20-30% of semen vol)
- Proteolytic enzymes help break down clotting proteins from seminal fluid
- Citric acid: used by sperm for ATP production via Krebs cycle
- Seminal plasmin: protein with antibiotic properties
- pH 6.5
- Prostatic fluid (20-30% of semen vol)
- Testes
- Semen
- Alkaline pH 7.2-7.7
- Composed of spermatozoa and seminal fluid
- Untitled
- Internal anatomy of penis
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