Human Reproductive Flashcards
Functions of testes
- Produces sperm
- Produces male sex hormone, testosterone, from puberty onwards - responsible for development and maintenance of secondary sexual characteristics
Functions of epididymis
Stores inactive sperms from the testes temporarily before they entire sperm duct
Functions of scrotum
- Pouch-like sac that holds the testes
- Outside main body cavity to keep testes slightly below body temp for sperm development
Functions of sperm duct/vas deferens
Carries sperms from testis to the urethra
Functions of urethra
A tube which passes from bladder to centre of penis to outside of body
Provides common passage for discharge of semen and urine
Function of prostate gland
Secretes fluid to: activate+nourish sperms, neutralise acidity in female reproductive tract, provide medium for sperm to swim, mixture of fluid and sperms called semen
Function of penis
Erectile organ which enters vagina of woman during sexual intercourse to deposit semen
Function of sperm(head)
Head contains large nucleus with small amount of cytoplasm, carried haploid set of chromosomes, acrosome containing enzymes is present, enzymes break down part of egg membrane to allow sperm to penetrate egg during fertilisation
Function of sperm(middle piece)
Contains many mitochondria to provide energy for sperms to swim towards the egg
Function of sperm(flagellum
Beating movement of flagellum enables sperm to swim towards the egg
Function of ovary
Produces ovum- released from ovaries once matured
Produces female sex hormones, responsible for menstrual cycle and development and maintenance of secondary sexual characteristics in females
Function of oviduct(fallopian tube)
Narrow muscular tube leading from ovaries to uterus, with funnel-like opening lying close to ovaries. Transports ovum to uterus by beating of cilia lining wall of oviduct, site of fertilisation
Function of uterus
Site of implantation of fertilised egg and fetal development
Offers protection + stable internal environment for embryo to develop
Inner lining forms part of placenta to supply nutrients of oxygen to fetus and remove carbon dioxide and nitrogenous waste from fetus
Muscular wall contracts, expels fetus at birth
Functions of cervix
Connects uterus to vagina
Function of vagina
Holds penis during copulation to receive sperm, birth canal for fetus
Structure of ovum
Abundant cytoplasm containing small amount of yolk, provide nutrients for embryo before implantation, spherical with large nucleus containing haploid set of chromosomes, surrounded by additional outer membrane
Difference in function between sperm and ovum
Sperm: Fertilise ovum
Ovum: Provide nutrients for development of the embryo before implantation
Similarities between sperm and ovum
Both provides haploid set of chromosomes (23 chromosomes)
What happens in day 1-5 of menstrual cycle
Low levels of oestrogen and progesterone causes uterine lining to break down and shed in the form of menstrual blood out of the body through the vagina
What happens in day 6-13 of the menstrual cycle
Ovary produces hormone called oestrogen, which stimulates repair and growth of uterine lining. Uterine lining becomes thick and spongy with blood vessels
What happens during day 14 of menstruation
One of the two ovaries releases an ovum into the oviduct, known as ovulation
What happens during day 15-28 of menstruation
Ovary produces a hormone called progesterone
(Effect of progesterone)
Oestrogen production decreases
If ovum is not fertilised, progesterone levels decreases and uterine lining break downs.
What is the effect of progesterone
Stimulates uterus to maintain uterine lining by causing it to thicken further and be supplied with blood capillaries, preparing for implantation of embryo. Inhibits ovulation and further development of the ova.
What happens when ovum is fertilised
Embryo secretes human chorionic gonadotropin, which maintains secretion of progesterone by the ovary
What factors affect the length of the menstrual cycle
Stress, tiredness, unbalanced diet or malnutrition
Why is the fertile period from day 11 to day 16
Ovum can survive one to two days in oviduct, sperm can live for three to four days in female reproductive system, sperms released into vagina around day 11 have a chance to fertilise the ovum
What happens during fertilisation
- surrounded by few layers of follicle cells
- penetrate, acrosome, enzymes, disperse follicle cells, break down
- Only one sperm, haploid sperm, fuses, haploid ovum, diploid zygote
- As soon as, membrane changes, no other sperms, eventually die
What happens during implantation
- Cilia lining oviduct sweep zygote along oviduct
- Peristaltic movement of oviduct helped move zygote towards uterus
- Zygote divides by mitosis to form hollow ball of cells called embryo
- Five days embryo to reach uterus
- Developing embryo moves down uterus and embeds itself in uterine lining, known as implantation
Describe development of placenta and amniotic sac
Implantation, villi, grow
Villi, uterine lining, embedded, make up placenta
Umbilical cord, attaches, placenta
Membrane, amniotic sac, develops
Encloses embryo, amniotic cavity
Fluid is amniotic fluid
Function of the amniotic fluid
absorb shock, support and cushion the fetus before birth
as cannot be compressed, protects fetus against mechanically injury
allows the fetus a certain degree of movement, promotes muscle dvlp
lubricates reduces friction in vagina or birth canal during birth
Functions of placenta
- Performs functions of nutrition, gaseous exchange and excretion
- It allows oxygen and nutrient to diffuse through placenta from m-f
- Allows CO2 and urea to diffuse through placenta from f-m
- Protective antibodies to diffuse from m-f blood protect against certain diseases
- Produces progesterone which maintains uterine lining in healthy state during pregnancy
Go study structure of placenta
ok!
Functions of umbilical cord
Attaches fetus to the placenta
Contains two umbilical arteries transports deoxygenated blood and metabolic waste products from f-p
Contains one umbilical veins that transports oxygenated blood and food substances to fetus
Define sexually transmitted infection
A disease that spreads through sexual intercourse
How can STIs be transmitted
Through semen, fluid in vagina, and blood
How does HIV destroy the body
- destroys lymphocytes
- unable to produce sufficient antibodies to protect from other infections
- may take months to years before HIV develops to AIDS, normally mild infections become fatal
What are the modes of transmission of HIV
- Unprotected sexual intercourse with an infected person
- Passed from m-f during pregnancy
- Blood transfusion with blood an infected person
- Sharing of hypodermic needles
How to prevent HIV infection
- Educating public on how its spread and precautions
- Keep to one sex partner
- Using condom
- Do not abuse drugs, drug addicts tend to share needles
- Needles used are sterilised
- Do not share instruments that break skin, contaminated w blood
