reproductive system Flashcards
testes
male gonads that produce sperm
components of system of ducts
epididymis, ductus deferens, ejaculatory ducts, urethra
Accessory glands
seminal vesicles, prostate, and bulbourethral glands
the function of the scrotum
- scrotal location and muscle contraction regulate the temperature of testes
- normal sperm production occurs 2-3 degrees lower than normal body temp
- response to a cooler temperature
muscles contract to pull testes close to the body - in warmer temp - reverse
structure of the testes
- one teste in each sac of the scrotum
- tunica albuginea is located deep to tunica vaginalis which form lobules that contain seminiferous tubules (spermeogenesis)
structure of epididymis
Head, body and tail
Spermatogenic cells
begin sperm production at puberty
Sertoli cells
nourish spermatogenetic cells
Leydig cells
secrete testosterone
structure of spermatozoon
Head - nucleus - acrosome Mid-piece - mitochondria Flagellar Tail
How is spermatogenesis hormonally controlled?
- negative feedback loops control testosterone release and spermatogenesis
- GnRH = increased production at puberty and stimulates secretion of LH and FSH
- LH = secretes testosterone
- FSH = secret ABP
Testosterone
suppresses LH and GnRH secretion
DHT
stimulates the development of external genitals
ABP
binds to and keeps testosterone levels high
inhibin
inhibits FSH secretion
major effects of testosterone and DHT
- prenatal development
- development of male sexual characteristics and sexual function
- stimulation of anabolism
duct of testis
seminiferous tubules
epididymis
- site of sperm maturation and storage
- consists of ductus epididymis
ductus deferens
- terminal portion is the ampulla
- conveys sperm from epididymis towards the urethra
- storage and re-absorption of sperm
spermatic cord
- supporting structure ascends out of the scrotum
- contains duct deferens, blood vessels, nerves, lymphatic vessels, cremaster muscles
ejaculatory ducts
- formed by the duct of seminal vesicle and ampulla of ductus deferens
- eject sperm and seminal vesicle secretion from urethra to exterior
urethra
- shared by reproductive and urinary systems
seminal vesicles function
- alkaline fluid
- fructose
- prostaglandins
- clotting proteins
bulbourethral glands function
- pea-sized glands
- alkaline fluid
- secrete lubricating mucus
what is semen?
- combination of sperm and seminal fluid
structure of the penis
- contains urethra
- passage from sperm and urine
- 3 erectile tissue
- during erection, the erectile tissues become engorged with blood
Erection
- somatic and visceral fibres transmit sexual sensations to the brain
- parasympathetic NS mostly causes vasodilation of penile arterioles
- superficial venules compress = helps maintain erection
the function of the female reproductive system
- produces female gonads
- provides a site for fertilisation
- provides a site for the development of the concepts
- allows birth
- provides nourishment for the new-born
components of the female reproductive system
- ovaries produce oocytes and hormones
- Uterine tubes (fallopian tubes) transport fertilised ova
- uterus where foetal development occurs
- mammary glands produce milk
structure of the ovarian cortex
contains ovarian follicles
ovarian medulla
contains blood vessels, lymphatics and nerves
ovarian follicle
consist of oocytes and associated cells in various stages of development.
- mature follicles expels a secondary oocyte by a process called ovulation
corpus luteum
- develops from the remnants of an ovulated follicle
- produces progesterone, oestrogens and inhibin
- degenerates into a corpus albicans
what is oogenesis?
- occurs in ovaries. It results in the formation of a single haploid secondary oocyte
- involves mitosis, meiosis and differentiation
stages of the ovarian cycle
1, primordial follicles in an egg nest
- formation of primary follicles
- formation of secondary follicle
- formation of tertiary follicle
- ovulation
- formation of corpus luteum
- formation of corpus albicans
events in oogenesis
- prenatal stage
- primary oocyte grow and from epithelium from cells such as granular cells - Antral stage
The fluid-filled area, present with granulosa cells, combines to form a central fluid-filled space called the antrum (secondary follicles) which develop due to FSH and LH. - Ovulation
ovulation in oogenesis
- primary oocytes grow bigger and follicle cells rise in number, causing the follicle to grow larger too (meiosis 1)
- Once the primary oocytes mature and become secondary oocyte =, the follicle breaks and the secondary oocyte is liberated in the fallopian tube (mataphase2)
zona pellucida
- clear area between oocyte and granulosa cells
corona radiata
- granulosa cells attached to zona pellucid - still attached to oocyte at ovulation
antrum
- formed by granulosa and secretes fluid
structure of oviducts
- narrow tubes extend laterally from the uterus
- not directly connected to the ovaries
Fimbriae (finger-like opens near ovary)
Ampulla (central region)
Isthmus (narrowest portion near uterus)
function of oviduct
- transport ova from the ovaries to the uterus and are site of fertilization
- lumen is lined with ciliated epithelium with secretory cells that provide nutrients
- In the wall of the uterine tube is smooth muscle
Peristalsis helps move the ovum down to the uterus
events occurring in the uterine tube (oviduct)
- fimbriae sweep oocyte unto tube
- cilia and peristalsis move it along
- sperm reaches oocyte in the ampulla, fertilisation occurs
- zygote reaches the uterus
function of uterus
- transport of sperm
- menstruation
- implantation of a fertilized ovum
- development of a foetus during pregnancy
Uterine wall
- blood supply to the endometrial layers alters throughout the uterine cycle
- 3 layers
1. endometrium
epithelial layer - stratum functionalis - shed during menstruation
- stratum basalis - replaces stratum functionalis each month
2. myometrium - smooth muscle
3. perimetrium - visceral peritoneum
the function of the vagina
passageway for sperm and menstral flow and lower portion of the birth canal.
Vagina histology
- muscosal epithelial layer
- smooth muscle allows for considerable stretch
- loose connective tissue that binds it with other organs
between urinary bladder and the rectum
structure of vulva
- external genitalia of the female
- mon pubis - fatty pad over the public symphysis
- labia majora and minora - folds of skin encircling vestibule
- the urethral and vaginal openings = within the vestibule
- clitoris - small mass of erectile tissue
Each breast contains
- nipple - pigmented protection
- areola - pink area around the nipple
- lateritious ducts - releases milk
- mammary glands = synthesis of milk, secretion and ejection of milk
menstrual cycle
- involves changes in the endometrium of the uterus
- precipitation of uterus to receive a fertilized ovum
- if implantation doesn’t occur, the stratum functional is shed during menstration.
GnRH in the reproductive system
- secreted by the hypothalamus
- stimulates the release of FSH and LH by the anterior pituitary gland
FSH role in the reproductive system
growth of follicles that secrete oestrogen
LH role in the reproductive system
stimulates ovulation and promotes the formation of the corpus luteum which secretes oestrogen, progesterone and inhibin.
role of progesterone in the reproductive system
prepares the uterus for implantation and the mammary glands for milk secretion
inhibin in the reproductive system
inhibits the secretion of FSH
function of oestrogen
- promotion of the development and maintenance of female reproductive structures, secondary sex characteristics.
- increase protein anabolism
- inhibit the release of GnRH
- with progesterone, prepares the endometrium for implantation
