Module 11 - Male Reproduction Flashcards
Male Reproductive Organs
Male Reproductive Organs
Testes – production of sperm & androgens
System of ducts
Accessory sex glands
Supporting structure - Penis
System of ducts
System of ducts
Ductus epididymis
Ductus deferens
Ejaculatory duct
Urethra
Accessory Sex Glands
Accessory sex glands
Seminal vesicles
Prostate gland
Bulbourethral glands
Scrotum
Scrotum
Cutaneous outpouching
Muscular sack – extending from body behind penis
Supports testes within
Outside body for temp regulation
Dartos muscles
Scrotal septum
Cremaster muscles
Raphe
Scrotum - Temp Regulation
Outside body for temp regulation – body temp too warm – 2-4C lower
Too cold – brings testes towards pelvic cavity - cremaster muscles
Warm – scrotum relaxes – promotes heat loss – away from pelvic cavity
Scrotum - Dartos Muscle
Dartos muscles – subcutaneous muscle layer
Scrotum - Cremaster Muscles
Cremaster muscles – 2 – internal oblique muscles of ab wall – cover each testis – muscular net
Regulates temp of testes
Scrotum - Scrotal Septum
Scrotal septum – divides into 2 compartments – muscular partition
Scrotum - Raphe
Raphe – externally – raised medial thickening on surfaces – base of penis to anus
Fusion line of two compartments
Testes
Testes
Male gonads
Produce sperm and androgens – testosterone
Paired ovals – 4-5cm
Housed in scrotum
Testes - Hormones
Stim’ed by anterior pituitary gland hormones
Follicle stimulating hormones – Sertoli
Luteinizing – stims Leydig cells
Testes - Surrounding Layers
Surrounding layers of connective tissue – protection
Outer tunic vaginalis – serous membrane
Parietal
Thin visceral
Tunic albuginea – tough white, dense connective – covering testes – forms septa
Septa – divides testis into 300-400 lobules
Seminiferous tubules
Seminiferous tubules – within lobules – sperms cells made here
Tightly coiled convoluted tubules
Developing sperm cells – surrounded lumen
Lumen – hollow center of tubule – formed sperm released into duct system
Cells:
Sertoli cells
Germ cells
Leydig cells
Sertoli Cells
Sertoli cells – supporting cells – sustentacular cells
Surround all stages of developing sperm cells
Branching
Nourish all germ cells as they differentiate
Produces androgen bind protein
Secrete signaling molecules
Promote sperm production – follicle-stimulating hormone
Control germ cells lifecycle
Control movement and release into lumen
Secrete fluid for sperm transport and hormone inhibin
Extend from germ cells – peripheral basement membrane
Tight junctions – blood-testis barrier
Testes - Sertoli Cells - Blood-testis barrier
Tight junctions – blood-testis barrier
Keep bloodborne substances out
Keeps surface antigens on developing sperm from bloodstream
Prevent immune response
Germ Cells
Germ cells
Spermatogonia – line basement membrane inside tubule
Stem cells of testis
Spermatogenesis – process of sperm development
Spermatogenesis - Cell differentiation
Primary
Secondary spermatocytes
Spermatids
Sperm
Spermatogenesis – process of sperm development
Leydig cells
Leydig cells – spaces b/w seminiferous tubules – Produce and secrete testosterone Luteinizing hormone controls
Meiosis
Meiosis
Meiosis – special type of nuclear division
Cell cycle in gonads producing gametes
Gametes – 23 chromosomes – one of each pair to be delivered to female
Reduces 46 chromosomes to 23
Diploid – 46 – complete copy of father’s genetic material
Haploid – 23 – result 4 haploid cells
Mitosis
Cell undergoes two rounds of division
Meiosis I and Meiosis II – phases: PMAT
Result – four haploid daughter cells – spermatids
Mitosis - Meiosis
Mitosis – spermatogonia stem cell – single division
Two identical diploid daughter cells
Spermatogonia to primary spermatocyte
Meiosis I
Meiosis I – primary spermatocyte to secondary
Prophase I – homologous chromosomes pair and exchange genetic info
Metaphase I – homologous chromosomes line up at equator
Tetrads line up – centers of pairs
Anaphase I – chromosomes move to opposite poles
Telophase I – spilt into two cells
Prophase - Crossing Over
Crossing over – shuffles genes b/w non-sister chromatids of homologous (same pattern of genes) chromosomes – genetic recombination – exchange pieces of chromatids
Meiosis II
Meiosis II – secondary spermatocyte to spermatid – two cells follow same
Prophase II – chromatin condense
Metaphase II – line at center
Anaphase II – sister chromatids spilt and move to opposite dies
Telophase II – pinch in center and divide
Result – four haploid daughter cells – spermatids
Spermatogenesis
Spermatogenesis
in seminiferous tubules
Begins at puberty – constant through man’s life
Produces haploid sperm
Begins with mitosis of diploid spermatogonia – complete copies of father’s DNA
Results – 2 diploid cells
One remains spermatogonium – stem cell
Other – primary spermatocyte – DNA is replicated
Meiosis I – 23 pairs of chromosomes separate
Results – secondary spermatocytes
Meiosis II – each divide – similar to mitosis
Results – 4 haploid cells – Spermatids
Final stage – maturation of spermatids into sperm – reducing cytoplasm – tail development
Sperm
Sperm
100-300 million produced daily
Wants to fertilize a secondary oocyte
48hr lifespan in woman
Head
Haploid nucleus – little cytoplasm
Acrosome – covering – filled with lysosomal enzymes – help with fertilization
Middle
Packed with mitochondria – power tail – flagellum
Tail
Flagellum – tail – produces movement of sperm
Hormone Control
Hormones
Negative feedback loop – control of testosterone and inhibin
Hypothalamus and anterior pituitary gland – main control center
Gonadotropin-releasing hormone (GnRH)
stims release from pituitary gland
Anterior pituitary gland stims release of
Follicle-stimulating Hormone
Luteinizing Hormone
Follicle-stimulating Hormone
Follicle-stimulating Hormone
Binds to Sertoli cells
Initiates spermatogenesis
Sertoli cells produce Inhibin
Regulates rate of spermatogenesis
Stims pituitary to slow testosterone secretion
Luteinizing Hormone
Luteinizing Hormone
Low testosterone in blood stims release of GnRH -hypothalamus
Stims pituitary gland to release LH
Binds to Leydig cells
Stims production of Testosterone
Asist w/ spermatogenesis
Ductus epididymis
Ductus epididymis – sperm maturity
Long very coiled tubule attached to testis
Sperm enters the head of epididymis from
seminiferous tubules
Matures as it travels to the tail
Moves sperm by contraction of smooth muscle – cannot move independently till mature
Testosterone
Testosterone
Growth, development, function
Maintenance of sex organs
Stim’s bone growth,
protein anabolism,
sperm maturation
Secondary male sex
characteristics
Ductus (vas) Deferens
Ductus (vas) Deferens – stores sperm
Coiled tubule
Move it forward for ejaculation
Sperm exit tail for epididymis – pushed from contraction
To ductus deferens
Ductus (Vas) Deferens - Pathway
Pathway
Exits scrotum by spermatic cord
Contains connective tissue, blood vessels, nerves
Extends too inguinal canal – in abdominal wall
Weak spot – where spermatic cord passes
Ampulla – enlarged end of duct
sperm reservoir
Units Ampulla of ductus deference w/ seminal vesicles
Make Semen
Fluid mixture with sperm – fructose – used from sperm mitochondria for ATP – Power to move
Ejaculatory duct – ampulla and seminal vesicle unit and turn into
Function is ejection of spermatozoa into urethra
Urethra – passageway for semen and urine
Penis
Penis
Organ of copulation (intercourse)
- delivers spermatozoa into vagina
Flaccid – non-sexual action – urination
Erect – sexual action
Penis gets dilated by nitric oxide (NO) – causes vasodilation – blood fills the penis
Root
Body – arteries – corpora cavernosa & cavernosal – 3 columns of erectile tissue – around urethra
Glans penis – end – concentration of nerve endings
Seminal Vesicle
Seminal Vesicle
Secrete alkaline, viscous fluid
Neutralize acid in male urethra and female tract
Fructose
Prostaglandins
Clotting proteins
Seminal Vesicle - Fructose
Fructose – ATP for sperm – power to move independently
Seminal Vesicles - Prostaglandins
Prostaglandins
Sperm motility and viability
Facilitates uterine contraction during intercourse – influences movement into female tract
Seminal Vesicles - Clotting Proteins
Clotting proteins – Semenogelin
Coagulation after ejaculation
Helps immobilize sperm – glue hold them together – gives them a better change in female tract
Prostate Gland
Prostate Gland
Secretes milk, slight acidic fluid
Citric acid – ATP for sperm
Acid phosphate
Proteolytic enzymes – liquefy coagulated semen
Bulbourethral (Cowper’s) Gland
Bulbourethral (Cowper’s) Gland
Secretes alkaline mucus for lubrication and acid neutralization
Semen - Final Product - ejaculation
Semen – results
Mixture of spermatozoa and gland secretions
Ejaculation
Coagulated w/in 5 minutes – clotting proteins – seminal vesicles
10-20, re-liquified b/c enzymes from prostate
