Reproductive physiology Flashcards
What is Biological sex?
Identifies gender
Results from chromosomes
Results in production of gametes i.e. Sperm/ Ova
What is the result of sexual reproduction
Offspring that differ genetically from both parents.
List 4 functions of sexual intercourse
Required for sexual reproduction
Sexual activity
Sexual pleasure
Human bonding
Which 3 systems are linked to parenting, fertilitly, reward and pleasure?
Control of movements by nigrostriatal tract;
Pathways for reward + pleasure in mesolimbic dopaminergic system.
Neuroendocrine pathways regulating fertility + parenting
What encourages procreation?
Activation of pleasure pathways in the brain
What is penile erection controlled by?
Thoughts in the brain (limbic system) via the spinal cord + efferent nervous system.
Tactile stimulus can activate the afferent system via the pudendal nerve, feeding into the spinal cord
Describe the changes that occur during penile erection
Increased PNS activity to smooth muscle of pudendal artery
Increases NO, which increases production of cGMP
Induces dilation of arterial smooth muscle
Counteracts SNS maintained myogenic tone
Increases blood flow in corpus cavernosum, compresses dorsal vein, restricting outflow of blood
Urethra protected from increased pressure by surrounding corpus spongiosum
What reverses the changes leading to penile erection? How can this mechanism be utilised therapeutically?
cGMP being de-activated by a phosphodiesterase
Viagra inhibits the phosphodiesterase, thus potentiating the effects of cGMP
What is the female erectile tissue? What occurs during erection?
Clitoris
Increases in size due to increased blood flow
Same mechanism as penile executive tissue
What are the main functions of the Male reproductive system?
Provision of androgens: to initiate + sustain male phenotype
Production of mature sperm
Describe the function and contents of the Testis and Epididymis.
Testis: contains seminiferous tubules (produce sperm) + Leydig cells (produce testosterone)
Epididymis: store sperm prior to ejaculation.
Describe the passage of sperm at ejaculation
Sperm pass through the vas deferens + mix with fluid from seminal vesicles.
Fluid leaves ejaculatory duct + passes to urethra where it mixes with secretions from prostate gland.
How does spermatogenesis occur through life?
Starts at puberty + is continuous
Sperm quantity + quality decrease with age
200 million/ day
Describe the HPG axis in males
Hypothalamus releases GnRH
GnRH stimulates anterior pituitary secretion of FSH + LH
FSH stimulates SERTOLLI cells to grow, produce androgen binding protein + Inhibin
LH stimulates LEYDIG cells to produce testosterone
Describe the feedback effects in the HPG axis in males
Testosterone downregulates production of GnRH, LH + FSH
Inhibin downregulates production of LH + FSH