16 | Reproduction in humans Flashcards
Function of testis
produces sperms and male sex hormones such as testosterone
function of epididymis
stores inactive sperms from testis
function of spermatic cord
supplies blood to testis
function of scrotum
keeps the testes outside the main body so that sperms can develop properly at lower temperature
function of sperm duct (vas deferens)
transport sperms from testes to the urethra
function of seminal vesicle
stores sperms temporarily before they are released into the urethra
function of prostate gland, cowper’s gland and seminal vesicle
release fluids that contain nutrients and enzymes that are needed to activate the sperm cells
function of prostate gland
produces alkaline, milky fluid that contains nutrients and enzymes which nourish and activates the sperms and helps them to swim towards the egg.
function of urethra
extends from the urinary bladder, through the penis, to the outside of the body where urine and semen are passed out.
function of penis
erectile organ that becomes hard during sexual intercourse in order to enter the vagina to deposit semen containing sperm.
parts of the sperm
head
middle piece
tail or flagellum
head of the sperm
- about 2.5um wide
- contains a large nucleus with a small amount of cytoplasm. The nucleus carries a haploid set f chromosomes.
- an acrosome is also present. The acrosome is a vesicle containing enzymes. These enzymes break down part of the egg membrane so that the sperm can penetrate the egg during fertilisation
function of middle piece of sperm
contain numerous mitochondria to provide energy for the sperm to swim towards the egg.
function of tail or flagellum of sperm
enables sperm to swim towards the egg
function of ovary
produce eggs/ova (singular: ovum) and female sex hormones such as oestrogen and progesterone
function of oviduct (fallopian tube)
- narrow muscular tube leading from the ovary to the terus. It has a funnel-like opening close to the ovary. This makes it easier for the egg to enter the oviduct.
- transport eggs to the uterus by peristalsis of the muscular wall and sweeping action of the cilia.
- site of fertilisation
function of the uterus.
- a muscular organ with thick walls that are rich in blood capillaries.
- contains soft and smooth uterine lining that allows the implantation of embryo
- site of implantation of embryo and fetus development during pregnancy.
function of cervix
- a circular ring of muscles at the lower end of the uterus.
- allows menstrual bllood to flow out into the vagina during menstruation
- enlarges to allow passage of the fetus during birth
function of vagina (birth canal)
where semen is deposited during sexual intercourse
function of vulva
opening of the vagina
ovum
- has a large nucleus containing one haploid set of chromosomes
- has abundant cytoplasm which may contain a small amount of yolk
- surrounded by a cell surface membrane which in turn is surrounded by an outer membrane.
difference between male and female gamete
SMN
structure
motility
numbers
define puberty
puberty is the stage of human growth and development in which a person’s body bcomes capable of reproduction
what happens during puberty
during this period, the sex organs mature and sex hormones are released. The release of sex hormones result in the development of secondary sexual characteristics.
what is menstruation?
menstruation is the process whereby blood is discharged from the uterus via the vagina.
what is the average menstrual cycle?
28 days
what is the range for the menstrual cycle
the menstrual cycle can range from 21 to 33 days
changes in a follicle during the menstrual cycle
OVOC
stages of the menstrual cycle
- menstrual flow (day 1-5)
- follicle stage (day 6-13)
- ovulation (day 14)
- corpus luteum stage (day 15-28)
what is the first day of the menstrual cycle?
the first day of menstruation is the first day of the menstrual cycle
What happens during day 1-5?
- menstruation occurs
- during menstruation, the uterine lining breaks down and flows out throught the vagina.
- low levels of estrogen and progesterone
- follicle-stimulating hormone (FSH) released by anterior pituitary gland into bloodstream which stimulates follicle development and oestrogen secretion by the follicles.
What happens during day 6-13?
- FSH stimulates development of follicles in the ovaries and secretion of oestrogen.
- oestrogen causes the repair and growth of the uterine lining. The uterine lining becomes thick and spongy with blood vessels.
- oestrogen when present in high concentration inhibits FSH production, preventing maturation and development of more follicles.
- oestrogen at high concentration also stimulates the pituitary gland to secrete luteinising hormone (LH)
what happens on day 14?
- LH causes ovulation and formation of corpus luteum from the remains of the Graafian follicle
- the corpus luteum secretes progesterone and some oestrogen.
what happens on days 15-28?
- progesterone maintains the uterine lining by causing it to thicken further and be richly supplied with blood capillaries, preparing it for the implantation of the embryo
– inhibits ovulation
– inhibits FSH production
what happens if fertilisation occurs?
if fertilisation occurs, the embryo secretes a hormone that prevents the corpus luteum from breaking down
what happens if fertilisation does not occur?
If fertilisation does not occur, the corpus luteum will break down and hence, the uterine lining will not be maintained. It will be discharged throught the vagina (menstruation starts again)
How long can an egg survive in the female reproductive system?
24h
How long can a sperm survive in the female reproductive system?
approximately 3-4 days
when is the fertile period?
days 11-16
when does ovulation usually occur?
day 14
what happens during the fertile period?
the chance of getting pregnant is higher between days 11-16 (fertile period).
- the rest of the days in the menstrual cycle is known as the infertile period
Define fertilisation
fertilisation is the process involving the fusion of the nucleus of a haploid male gamete and the nucleus of a haploid female gamete to form a diploid zygote
Process of fertilisation
notes
what is the amniotic sac?
- An amniotic sac develops and encases the embryo
- the amniotic sac contains amniotic fluid, which allows the fetus to move within
functions of the amniotic sac?
SLAPMT
- support and cushions fetus before birth (S)
- lubricates and reduces friction in the vagina during birth (L)
- absorbs shock (if mother has a fall) (A)
- protects fetus from physical injury (P)
- allows fetus to move freely during growth, promoting muscular development (M)
- prevent temperatre fluctuations (T)
what is the fetal blood system?
the fetal blood system is separated from the maternal blood system. This is because the
- mother’s blood pressure is too high for the fetus
- mother and fetus may have different blood types, and agglutination may occur.
function of placenta
OF - ME - A - P
- Allows oxygen and dissolved food substances to diffuse from mother’s blood into fetus’s blood (OF)
- Allows metabolic waste or excretory products to diffuse from the fetus’s blood into the mother’s blood (ME)
- allows antibodies to diffuse from the mother’s blood into fetus’s blood to protect the fetus against diseases (A)
- produces progesterone which maintains the uterine lining in a healthy state during pregnancy (P)
Functions of the umbilical cord
DM - OF
- contains 2 umbilical arteries that transports deoxygenated blood and metabolic waste products from the fetus to the placenta (DM)
- contains 1 umbilical vein that transports oxygenated blood adn food substances from the placenta to the fetus (OF)
How can an STI be transmitted from an infected person to an uninfected person
via
- semen or vaginal fluid
- blood
what is acquired immunodeficiency syndrome (AIDS)?
AIDS is a STI that is caused by the human immunodeficiency virus (HIV)
what are the symptoms of AIDS?
FDPKBT
- chronic or persistent fever (F)
- severe diarrhoea that lasts for months (D)
- Pneumonia (P)
- Kaposi’s sarcoma (K)
- Brain infection (B)
- Widespread tuberculosis
How can aids be transmitted?
UHBP
- Unprotected sexual intercourse with an infected person (U)
- sharing of hypodermic needle with an infected person (H)
- through blood transfusion with blood from an infected person (B)
- substance exchange at the placenta (from infected mother to fetus) during pregnancy. (P)
Prevention and control of HIV?
SCOBD
- making sure needles used for hypodermic purposes are sterilised (e.g. for ear piercing or tattooing) (S)
- using a condom during sexual intercourse (C)
- keeping to a single sex partner, or abstaining from sex (O)
- Do not share instruments that can break skin and get contaminated with
blood (e.g. razors and toothbrushes) (B)
- not abusing drugs as drug abusers are in the habit of sharing needles (D)
