Week 12 Science and Scholarship: Reproduction Flashcards
list the functions of the male reproductive system
sperm cell production
sperm cell transfer
sex hormone production
Describe sperm cell production as a function of the male reproductive system
spermatogenesis in the seminiferous tubes of the testes
describe sperm cell transfer as a function of the male reproductive system
sperm transport through the vas deferens and urethra during ejaculation
Describe sex hormone production as a function of the male reproductive system
testosterone secretion by leydig cells in the testes
what are primary vs secondary sex organs
-Primary sex organs are the gonads; produce gametes and sex hormones; includes testes which produce sperm and androgens
-secondary sex organs are essential for caring and transporting sperm cells, include ducts (eg epididymites) which transport sperm, and accessory sex glands (eg prostate) which sustain sperm, and the penis which transfers sperm
what are secondary sex characteristics
features that are not essential for the reproductive process, but are generally considered social attractants eg body physique, hair and voice pitch or fat to breasts/abdomen and hips
name the male secondary sex characteristics
libido
growth of larynx and deeper voice
facial/body hair
developing muscle mass
external genitalia development
function of the testes
male reproductive organs that are responsible for producing sperm cells and testosterone (hormone)
describe scrotum
pouch of skin that houses and protects the testes in the male reproductive system
describe epididymis
a coiled tube located on outer posterior of each testicle, where sperm cells mature and are stored, transports sperm from testes to vas deferens
describe vas deferens
long fibromuscular tube that transport mature sperm cells from the epididymis to ejaculatory duct
describe ejaculatory ducts
short ducts formed by union of vas deferens and seminal vesicles, through which sperm and seminal fluid pass during ejaculation
describe seminal vesicle
sac-like structure that secrete a fluid (60-70% of volume of semen) rich in nutrients and fructose,
describe prostate gland
walnut-sized gland located below bladder that produces milky fluid containing enzymes, added to semen during ejaculation (contributes 20-30% of semen volume)
describe urethra
tube serving as a common passageway for both semen and urine. running through the penis (base to tip) and allowing elimination of waste and release of sperm
describe bulbourethral gland
aka Cowper’s gland, peas sized and paired,
-secretes a clear fluid that lubricates
-neutralises acidity of urethra prior to ejaculation by releasing alkaline mucous
describe penis
male external sex organ, responsible for transferring sperm into female reproductive system in sexual intercourse
name the components of male reproductive system
testes
scrotum
vas deferens
prostate gland
penis
epididymis
seminal vesicles
ejaculatory ducts
urethra
bulbourethral gland
structure of scrotum
-layer of smooth muscle (dartos)
-two skeletal cremaster muscles that descend from the abdomen and cover each teste, like a muscular net
-rich blood and nerve supply
function of scrotum
-to support and protect the testes
-to help regulate temperature of testes (35 degrees)
optimal temperature of testes
35 degrees ( 2 degree below normal)
why do testes require a temperature of 35 degrees
-enables optimal sperm production and testicular function
-ensures normal metabolism
-decreases risk of testicular cancer
name the mechanisms to regulate temperature of testes
-external location
-cremaster muscle
-dartos muscle
-counter-current heat exchange
how does external location regulate taste temperature
testes are located externally, away from warm pelvic cavity
how does cremaster muscle regulate testes temperature
-contracts to lift testes closer to pelvis (increasing temp)
-relaxes to drop testes away from pelvis (decreasing temp)
how does dartos muscle regulate testes temperature
-contracts (wrinkles) to reduce surface area for less heat loss
-relaxes (un-wrinkles) to increase surface area for more heat loss
how does counter-current heat exchange regulate testes temperature
-As the warm arterial blood descends into the scrotum, it passes through the pampiniform plexus.
-The cooler venous blood in the plexus absorbs heat from the arterial blood via conduction.
describe structure of testes
-elliptical
-divided into 300-400 compartments (lobules)
-each lobule contains a long tube (seminiferous tubule) which sperm are produced
what cells are found within the seminiferous tubules
spermatogenic cells and Sertoli cells
function of spermatogenic cells
evolve into sperm cells via spermiogenesis (mitosis then meiosis)
identify function of Sertoli cells
-support
-nutrient provision
-hromone secretion
-blood testis barrier
what structures are found between seminiferous tubules
leydig cells and blood vessels
function of leydig cells
produce androgens eg testosterone
function of blood vessels (interstitial)
exit pathway for androgens
define spermatogenesis
process by which sperm cells are formed
list the events of spermatogenesis
mitosis
meiosis I
meiosis II
maturation
define spermatogonia
undifferentiated male germ cells located in testes that are responsible for production of sperm cells via spermatogenesis
(2n)
define primary spermatocyte
specialised diploid cell that is formed from spermatogonia and undergoes meiosis I to produce two haploid secondary spermatocytes
(2n)
define secondary spermatocyte
haploid cells resulting from meiosis I division of primary spermatocytes which further undergo meiosis II to produce spermatids
(n)
define spermatid
immature haploid cells derived from secondary spermatocytes that undergo a series of morphological changes; form a tail, to eventually develop into mature sperm cells
(n)
define sperm cell
mature male reproductive cells produced through spermatogenesis, characterised by their elongated shape, a head containing genetic material and tail that facilitates movement (fertilisation)
(n)
describe the lineage of cells to make a sperm cell
spermatogonia
primary spermatocyte
secondary spermatocyte
spermatid
sperm cell
whats the difference between spermatogenesis and spermiogenesis
-spermatogenesis is the overall process by which sperm cells form
-spermiogenesis is the final stage of spermatogenesis where:
-acrosome (digestive enzyme)
-flagellum
-condensation of nucleus
-shedding excess cytoplasm
ALL develop
how do Sertoli cells provide ‘support’
physical support and protection for developing sperm cells within the SN tubules
how do Sertoli cells provide ‘nutrient provision’
provide nutrient and metabolic support to developing sperm cells, enduring proper growth and maturation
how do Sertoli cells provide ‘hormone secretion’
secrete hormones such as inhibin, which plays a role in slowing spermatogenesis
how do Sertoli cells play a role in ‘blood testis barrier’
separate sperm from bloodstream, preventing autoimmune response
where are Sertoli cells found
within SN tubules
name the major parts of sperm
acrosome
flagellum
axial filament
mid-piece
head
tail
end piece
function of acrosome of sperm
contains enzymes necessary for penetrating and fertilising the egg during fertilisation
function of flagellum of sperm
enables motility an propels sperm toward egg during fertilisation
function of axial filament of sperm
provides structural support and enables movement
function of head of sperm
essential for delivering genetic material to egg in fertilisation
function of mid piece of sperm
providing energy needed for sperms movement and mobility
function of tail of sperm
propels sperm forward
function of end piece of sperm
aids in propulsion and movement of sperm towards egg
identify each segment of male duct system
epididymis
vas deferens
ejaculatory duct
urethra
seminiferous tubules
reste testis
efferent ducts
function of seminiferous tubules
site of sperm and hormone production in testes
function of reste testis
networks of tubules that carry sperm from testes to efferent ducts
function of efferent ducts
connects reste testis to epididymis
list the changes that occur in sperm cells while in epididymis
-monitor and adjusting fluid composition
-recycling debris and damaged sperm
-protection of sperm in a conducive environment
-functional maturation (enable motility)
How does functional maturation occur in the epididymis
-variety of proteins that bind to sperm provide stability and protection and trigger flagellum movement
-initiated by androgens
list the constituents of semens
sperm cells (4%)
bulbourethral gland fluid (<1%)
seminal vesicle fluid (65%)
prostate gland fluid (30%)
name the three segments of the penis
root
body
glans
structure of the root of the penis
located at the base of the penis
-inside the body and not visible
structure of the body of the penis
-elongated component that is composed of three cylindrical columns of erectile tissue
-two large corpora cavernosa (on sides of penis)
-single corpus spongiosum on underside of penis that surrounds urethra
Describe the processes of orgasm in relation to erectile tissue
-sexual stimulation
-parasympathetic neuron’s release nitric oxide, this causes dilation of the arteries supplying the penis, thereby increasing blood flow to penis
-increasing pressure of arterial blood entering vascular spaces of erectile tissue compresses the veins of the penis, reducing flow of venous blood away from the penis
-follwoing orgasm sympathetic nerves contract the central artery of the penis and contract smooth muscle around the erectile tissues, which expels blood away from penis
describe the function of the corpus cavernosa
responsible for the rigidity of the penis during erection
describe the function of the corpus spongiosum
-protect the urethra
-less significant contributor to erection
where is testosterone produced
leydig cells in the testes
what are the functions of testosterone
-spermatogenesis
-sex drive
-secondary sex characteristics
how is testosterones function linked to spermatogenesis
testosterone initiates and maintains spermatogenesis; preventing infertility due to low testosterone
how does testosterone contribute to sex drive
maintains male sex drive (libido) so that reproduction and sexual desire are produced
how does testosterone contribute to secondary sex characteristics
-forms secondary sex characteristics, to increase attractive appeal and generate ‘male’ characteristic features
Describe the hormonal regulation of testosterone and sperm development
- hypothalamus initiates spermatogenesis by secreting GnRH, which stimulates the anterior pituitary gland to secrete FSH and LH
2.LH stimulates leydig cells to secrete testosterone, FHS stimulates Sertoli cells to secrete androgen-binding protein (ABP), ABP binds to testosterone, which allows it to become more concentrated in the SN tubules and maintains high testosterone levels
3.Increased levels of testosterone initiate spermatogenesis, this also has negative feedback on GnRH
4.Sertoli cells respond to rising sperm levels by secreting inhibin, this inhibits FSH secretion from the anterior pituitary gland thereby having negative feedback
5.Ciruclating testosterone stimulates sex drive (libido) and development of secondary sex characteristics
List the functions of the female reproductive system
oocyte production
hormone production
sperm reception
pregnancy/birth
describe oocyte production as a function of female reproductive system
production of oocytes (eggs) in ovaries (these are female gametes)
describe hormone production as a function of female reproductive system
-production of female sex hormones, including oestrogen and progesterone
-essential to normal function of reproductive system, and reproductive behaviour
describe sperm reception as a function of female reproductive system
-reception of spermatozoa from the male;
-includes structures that receive sperm and transport sperm to site of fertilisation
describe pregnancy/birth as a function of female reproductive system
-development and nourishment of a new individual, nurtures in uterus until birth
-provides nourishment (milk) after birth
what is the function of primary sex organ in females
the gonads are ovaries (produce oocytes and female sex hormones-progesterone and oestrogen)
what are secondary sex organs (female system)
-structures essential to: fertilisation of an oocyte, implantation of a fertilised oocyte; development of individual; parturition (childbirth)
-eg uterine tubules, uterus, vagina and mammary glands
list the structures that make up female reproductive system
ovaries
fallopian tubes
uterus
cervix
vagina
vulva
mammary glands
function of fallopian tubes
-site of fertilisation (ampulla)
-site of sperm maturation (isthmus)
function of uterus
-mechanical protection for embryo
-nutritional support for embryo
-waste removal for embryo
-contracts during birth
describe cervix
-lower part of uterus that connects to vagina
-passageway for sperm and plays role in childbirth
list functions of vagina
menstrual fluid
intercourse
childbirth
what is vulva
-external genitalia
-includes labia mojora, labia minora, clitoris and vaginal opening
function of mammary glands
-glands responsible for producing and secreting milk to nourish newborns after childbirth
Describe position of ovaries
-upper pelvic cavity
-either lateral side of uterus
structure of ovaries
-two ligaments (suspensory and ovarian ligament) support position of ovaries
-ovoid organs, nodular consistency
-outer cortex
-inner medulla
describe cortex (ovary)
-outer region
-contains oocytes and follicular cells that aggregate to from follicles
-site of folliculogenesis and oogenesis
-made of dense CT
describe medulla (ovary)
-inner central region
-contains blood vessels and nerves, this enables follicular hormones (oestrogen) to exit ovary and enter systemic circulation
-made of loose CT
define ovarian cycle
a series of hormonal and physiological changes that occur in the ovaries to prepare for the possibility of fertilization and pregnancy.
name the two processes in ovarian cycle
oogenesis and folliculogenesis