Male and Female Reproductive system

functions of the female reproductive system

• gamete production

• fertilisation (and intercourse)

• support of a developing embryo

• the structure(s) of the female reproductive system support one or more of these functions

• additionally, it responds to and secretes hormones

female reproductive system structures

• internal: ovaries, flimbriae, fallopian/uterine tubes (oviducts), uterus, endometrium, cervix, vagina

• external (vulva): labia minora and majora, clitorus

ovaries

• paired organs, located in the pelvic cavity (lower left and right abdomen)

  • supported by ligaments that maintain their position in the pelvic cavity

function of ovaries

• gamete production → oogenesis: produces oocytes (immature eggs)

• secrete oestrogen and progesterone (hormones)

• follicles mature and release an egg during ovulation

structure of ovaries supports its function

• they have a rich blood supply

• ovaries respond to luteninizing and follicle stimulating hormones

• they are located at the ends of the fallopian tube (oviduct)

fallopian tube structure

• infudibulum:

  • thin walled for flexibility to ‘catch’ the ovum

  • lined with cilia to sweep the egg

  • terminated in fimbriae to create currents to draw egg into fallopian tube

• ampulla:

  • usual site of fertilisation

  • thin walled with extensive, folded mucosa increasing surface area

  • cilia act to sweep egg towards uterus

• isthmus:

  • thick muscular walls

  • peristaltic contractions to drive zygote (if fertilised) towards uterus

• intramural:

  • shortest, narrowest section through muscular lining of uterine wall

fallopian tube function

• fertilisation → union of gametes (sperm and egg) forming a zygote

• move early embryo to uterus

structure of fallopian tube supports its function

• oviducts lined with cilia → sweet zygote (or ova) towards the uterus

• narrow and muscular → propel zygote (or ova) towards the uterus

fimbriae

• fimbriae are the finger like progections of oviduct nearest to the ovary

  • function: sweep across ovaries to guide ova into oviduct

uterus and endometrium

• muscular, pear shaped organ

• structures of the uterus include → uterine cavity, endometrium, cervix

• the endometrium lines the uterine wall, has a rich blood supply and thickens in preparation for implantation

function of uterus and endometrium

site of implantation and development of early embryo to foetus

structure of the uterus and endometrium support its function

• walls are flexible but strong → facilitate foetal development and childbirth

• lining is sensitive to hormonal signals → supporting healthy pregnancy

cervix

• lower, narrow portion of uterus

• connects uterus to vagina

• produces mucus that changes consistency during ovulatory and menstural cycles

• during labour, cervix dilates to allow childbirth

structure of the cervix supports its function

• narrow and flexible → dilates during childbirth

• hormone sensitive glands → modify mucus production to facilitate or inhibit sperm movement

  • ovulation: thin, watery and alkaline

  • menstruation: thick, cloudy and acidic

vagina

• muscular, elastic canal extending from the external vaginal opening to the cervix of the uterus

• lined with mucous membrane

• numerous rugae (folds) to allow for stretching

function of the vagina

• receives the penis during sexual intercourse

• provides a passage for menstrual flow from the uterus

• serves as the birth canal during labour and delivery

• supports self - cleaning through acidic secretions (low pH) that helps prevent infection

vulva

the collective term for the external genital structures of the female reproductive system. It includes the labia majora, labia minora, clitoris, vaginal opening, urethral opening, and associated glands and tissue

labia majora

• structure → thick, fatty outer folds of skin with covering of pubic hair after puberty

• function → protect inner structures (labia minora, vaginal opening, clitorus) from injury and infection

labia minora

• structure → thin, hairless inner folds located within the labia majora

• function → encloses and protects urethral and vaginal openings

clitoris

• structure → small, erectile structure with rich nerv and blood supply

• function → facilitates female sexual arousal and sexual response which can promote fertilisation

female reproductive system summary

organ	key structures	function(s)
ovary	oocytes (developing eggs) follicles	site of oogenesis (egg production) produces oestrogen and progesterone to regulate the menstrual and ovarian cycles
fallopian tube	fimbriae ciliated epithelium narrow muscular tube	fimbriae sweep ova into the tube after ovulation cilia and muscle contractions move ova (or zygote) towards uterus site of fertilisation
uterus	muscular wall (myometrium) endometrium	supports and protects a developing foetus responds to hormonal signals by thickening and shedding endometrium contracts during labour to aid delivery
cervix	cervical canal mucus producing glands	regulates sperm entry through mucus changes dilates during labour protects uterus from pathogens
vagina	muscular walls mucous membrane → rugae (folds)	receives the penis during intercourse passageway for menstrual flow and childbirth maintains acidic environment to reduce infection
vulva	labia majora labia minora clitoris urethral and vaginal openings	labia protect internal genital structures clitoris provides sexual arousal through nerve stimulation allows access to urinary and reproductive tracts

functions of the male reproductive system

• produces male gametes sperm through spermatogenesis

• secretes testosterone, the main male sex hormone

• stores, matures, and delivers sperm to the female reproductive tract to support and enable fertilisation

male reproductive system structures

• testes

• seminiferous tubules

• epididymis

• vas deferens

• seminal vesicles

• prostate glands

• urethra

• penis

• scrotum

testes

• microscopic structure: composed of many seminiferous tubules, tightly coiled and lined with

  • spermatogenetic (germ) cells → undergo mitosis/meiosis to form sperm

  • sertoli cells → nourish developing sperm and form the blood-testis barrier

• between tubules: interstitial leydig cells → secrete testosterone

function of testes

• produce sperm through spermatogenesis

• secrete testosterone, which regulates sperm production and male secondary sex characteristics

testes structure supports function

• highly coiled tubules → large surface area for sperm production

• sertoli cells → essential for sperm development and immune protection

• leydig cells close by local hormonal control

epididymis

• single long coiled duct (up to 6 meters if uncoiled), lined with epithelial tissue

• surrounded by smooth muscle

epididymis function

stores sperm and allows them to mature and gain motility

epididymis structure supports function

• length + coiling → prolonged contact time for sperm maturation

• epithelial lining → absorbs excess fluid, secrete substances for sperm development

• muscular wall → aids in sperm movement during ejaculation

vas deferens

• thick muscular tube

• layers of smooth muscle (longitudinal + circular)

epididymis function

transports sperm from epididymis to ejaculatory duct during ejaculation

structure of epididymis supports function

thick muscular walls → strong peristaltic contractions to propel sperm

seminal vesicles

• glandular tissue with folded mucosa

• lined with secretory epithelial tissue

function of seminal vesicles

• secretes 60% of the semen volume

• fructose (sperm energy)

• prostaglandins (stimulate female reproductive contractions)

• alkaline fluid (to buffer vaginal acidity)

structure of seminal vesicles supports function

• folded mucosa → increases surface area for fluid secretion

• alkaline and nourish secretions → enhance sperm viability

prostate gland

• lined with secretory epithelium

• surrounded by smooth muscle and connective tissue

prostate gland function

• secretes alkaline fluid (25-30% of semen)

• fluid contains enzymes (e.g. PSA) that → maintain liquid nature of sperm, neutralise acidic vaginal secretions

• fluid also contains citric acid to nourish sperm (literally for the krebs cycle)

structure of prostate glands supports function

• enzyme rich secretion → liquefies semen post-ejaculation for sperm motility

• alkaline pH → protects sperm in vaginal environment

bulbourethral (Cowper’s) gland

• small glands beneath the prostate

• lined with mucous - secreting epithelium

function of bulbourethral gland

• secretes mucus rich, alkaline fluid prior to ejaculation

• lubricates urethra and neutralises acidity of male urethra

structure of bulbourethral glands supports function

• small to obstruction, but located at urethra to maintain efficiency

• secretion clears and prepares urethra for sperm passage

urethra

• prostatic urethra: through prostate

• membranous urethra: through pelvic floor

• penile urethra: through penis

function of urethra

common duct for semen and urine

structure of urethra supports function

protects from mechanical and chemical damage, supports passage of semen of to female reproductive tract

penis

• erectile tissue → corpora cavernosa (2), sorpus spongiosum ( 1 surrounding urethra)

• lined with vascular spaces that fill with blood during erection

function of penis

• allows penetration during intercourse

• delivers semen into the female reproductive tract

structure of penis supports its function

• vascular spaces engorge to produce erection

• corpus spongiosum ensures the urethra remains open during ejaculation

scotrum

• skin, connective tissue, and smooth muscle layers

• contains testes and spermatic cord (contains blood and lymphatic vessel, nerves and vas deferens)

function of scrotum

maintains testes at a lower temperature (34ºC) required for sperm development

structure supports function

• muscles respond to temperature → contract in cold, relax in heat

• external positioning → cooler environment

testes → ejaculatory duct

• seminiferous tubules: site of spermatogenesis

  • sertoli cells → support and nourish developing sperm

  • leydig cells → secrete testosterone at site of spermatogenesis

• epididymis: storage and maturation of sperm cells

• vas deferns

• ejaculatory duct

summary of male reproductive system

structure	function
testes	produce sperm (via spermatogenesis) and secrete testosterone
seminiferous tubules	lined with germ cells and sertoli cells → site of sperm production
instersitial leydig cells	located between seminiferous tubules → produces testosterone
epididymis	stores and matures sperm after production
vas deferns	thick muscuar tube that transports sperm from epididmysis to ejaculatory duct
seminal vesiscles	secrete fructose rich fluid (energy for sperm) and prostaglandins (stimulate uterine contractions)
prostate gland	secretes alkaline fluid with enzyme to liquefy semen and support sperm survival
bulbourethral (cowper’s) glands	secrete alkaline mucus (pre-ejaculate) to lubricate and neutralise urine residue in the urethra
urethra	carries urine and semen to the outside of the body (shared duct)
penis	erectile organ penetration and semen delivery
scrotum	holds testes outside body to maintain cooler temperature (34º) essential for sperm development