Lec 25- Male Reproductive System Flashcards
Gametes
Reproductive or germ cells.
Sperm or eggs are formed in gonads by meiosis
Haploid
23 chromosomes
Fertilization
fusion of sperm and egg
Diploid
46 chromosomes
Chromosomes
a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
Homologous chromosome
Homologous chromosomes are made up of chromosome pairs of approximately the same length, centromere position, and staining pattern, for genes with the same corresponding loci. One homologous chromosome is inherited from the organism’s mother; the other is inherited from the organism’s father.
Autosomal chromosomes
22 of the 23 chromosomes from each parent.
Sex chomosomes
The 23rd pair are sex chromosomes.
XX = female
XY = male
The medical determination of sex is determined by the individuals genotype.
Barr body
Only 1 of 2 X’s in females become active.
Other forms clump of inactive heterochromatin called Barr body.
Used as test for chromosomal sex.
Gonads
Primary reproductive organs.
Will become testes in males; ovaries in females.
Testosterone
In absence of this, female sex organs will eventually develop.
TDF - testis determining factor
In the first trimester, the Y chromosome produces this compound which will convert the gonads to testes.
Produced by an SRY gene (sex-determining region of the Y chromosome)
SRY - sex determining region of the Y chromosme
Produces TDF (Testis-determining factor) which will convert the gonads to testes.
Sperm
Carry 23 chromosomes.
Ovum
Carry 23 chromosomes
Seminiferous tubules
In testes, where spermatogenesis occurs and interstitial tissue housing T-secreting Leydig cells.
Leydig cells
In testes, where spermatogenesis occurs and interstitial tissue housing T-secreting Leydig cells.
Ovarian follicles
An ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It secretes hormones that influence stages of the menstrual cycle. Women begin puberty with about 400,000 follicles, each with the potential to release an egg cell (ovum) at ovulation for fertilization.
cryptochidism
a condition in which one or both of the testes fail to descend from the abdomen into the scrotum.
Accessory sex organs
In males include; epididymis, vas deferens, seminal vesicles, and ejaculatory duct.
In females; uterus and fallopian tubes
Wolffian ducts
Male accessory sex organs are derived from wolffian ducts.
Epididymis
a highly convoluted duct behind the testis, along which sperm passes to the vas deferens.
vas deferens
the duct which conveys sperm from the testicle to the urethra.
seminal vesicles
The seminal vesicles (Latin: glandulae vesiculosae), vesicular glands, or seminal glands, are a pair of simple tubular glands posteroinferior to the urinary bladder of some male mammals. Seminal vesicles are located within the pelvis. They secrete fluid that partly composes the semen.
Ejaculatory duct
The ejaculatory ducts (ductus ejaculatorii) are paired structures in male anatomy. Each ejaculatory duct is formed by the union of the vas deferens with the duct of the seminal vesicle. They pass through the prostate, and open into the urethra at the seminal colliculus.
Mullerian ducts
Female accessory sex organs are derived from Mullerian ducts and include uterus and fallopian tubes.
Uterus
the organ in the lower body of a woman or female mammal where offspring are conceived and in which they gestate before birth; the womb.
Fallopian tubes
One of the two Fallopian tubes that transport the egg from the ovary to the uterus (the womb). In the diagram, the Fallopian tubes are not labeled but are well shown running between the uterus and ovaries. The Fallopian tubes have small hair-like projections called cilia on the cells of the lining.
External genitelia
The external genitalia are the accessory structures of the female reproductive system that are external to the vagina. They are also referred to as the vulva or pudendum. The external genitalia include the labia majora, mons pubis, labia minora, clitoris, and glands within the vestibule.
Penis
Testis secretions (testosterone) masculinize to form penis, male urethra and scortum.
Male urethra
Tube from bladder to external environment.
Scortum
Holds the testis
Homologous structures
In absence of testosterone, clitoris forms instead of penis and labia instead of scrotum. (are homologous structures)
Puberty
Both testes and ovaries remain inactive after birth until puberty.
At puberty hypothalamus increases GnRH secretion.
This stimulates increased LH and FSH.
Which stimulates sex steroid secretion.
Which drives changes in secondary sex characteristics and menarche (1st menstral flow)
Inhibin
Inhibin from Sertolis provides negative feedback on FSH.
Estradiol
Estrogen (Estradiol - 17B) and its derivatives are produced by the enzyme aromatase.
Aromatase
Enzyme
Estrogen (Estradiol - 17B) and its derivatives are produced by the enzyme aromatase.
Sertoli cells
of STs (seminiferous tubules) contain receptors for FSH.
Spermatogenesis
Creation of sperm. Stimulated by FSH.
Spermatogonia
are embedded in and nurtured by adjacent Sertolis cells.
Meiosis
stage 2 of spermatogenesis
Blood-testes barrier
prevents autoimmune destruction, created by sertolis cells.
ABP - androgen binding protein
Sertolis secretes ABP into lumen of STs. Binds stestosterone, concentrating it in tubules.
Acrosome
Tip of head of sperm
Rete testis
Spermatozoa and fluids exit ST’s via rete testes.
Efferent ductules
Pass through this to epididymis.
Prostate
Where ejaculatory duct and urethra merge.
Semen
Ejaculatory fluid
Oligospermia
Sperm count less than 20 million
Gossypol
interferes with sperm development
Vasectemy
each vas deferen is cut and tied.
