The Human Reproductive System Flashcards
puberty
the beginning of sexual maturity
primary sexual characteristics
features that are essential for reproduction, ie ovaries, testes
secondary sexual characteristics
physical features that distinguish males from females, not including the sex organs
males - deep voice, facial hair
females - enlargement of breasts, widening of pelvis
semen
fluid containing sperm and seminal fluid
gamete
sex cell
haploid
one of each type of chromosome in the nucleus
n=23
diploid
two of each type of chromosome in the nucleus
n=46
mitosis
a form of nuclear division in which one nucleus divides to form two nuclei, each containing identical sets of chromosomes
meiosis
a form of nuclear division in which the daughter nuclei contain half the chromosome number of the parent nucleus
ovulation
the release of an egg from an ovary
implantation
the embedding of the fertilised egg into the endometrium
the menstrual cycle
a monthly cycle that occurs in females if fertilisation has not taken place
its role is to produce eggs and prepare the uterus for pregnancy
menstruation
the shedding of the endometrium during days 1-5 of the menstrual cycle
hormones
chemical messengers, produced in specialised glands, and transported in the blood to a target organ where they have their effect
chemical nature: made of protein
feedback
production (or inhibition) of one hormone inhibits (or stimulates) the production of itself (or another hormone)
negative feedback
when a high level of a hormone in the blood inhibits the production of another hormone
menopause
when ovulation and menstruation stop happening in a female
fertilisation
the fusion of the egg and sperm nuclei to form a diploid zygote
fertile period
the time during the menstrual cycle when an egg may be fertilised
infertility
the inability to produce gametes or offspring
in-vitro fertilisation
removing the gametes (egg and sperm) and fertilising (fusing) them outside the body
copulation
the act of sexual reproduction
ejaculation
the release of semen into the vagina
birth control
methods employed to limit the number of children that are born
contraception
preventing the egg and sperm from meeting
morula
a solid ball of cells
blastocyst
fluid filled ball of cells
lactation
the secretion of milk from the mammary glands
breastfeeding
the feeding of a baby/infant directly from the breast
testes
produce sperm by meiosis (exocrine function) and testosterone (endocrine function)
scrotum
hold testes at 2°C lower than body temp. for optimum sperm production
epididymus
stores sperm and allow them to mature
sperm ducts (vas deferens)
carry sperm from the epididymus to the urethra
seminal vesicles/prostate gland/cowper’s gland
add seminal fluid to the sperm to form semen
seminal fluid
contains fructose to nourish the sperm
medium for sperm to swim
urethra
transports semen through penis
testosterone
male hormone responsible for sperm production and development of secondary sexual characteristics
sperm lifecycle in the female reproductive system
up to seven days
sperm structure
head - acrosome (contains digestive enzymes required to enter the egg)
middle - midpiece (contains mitochondria to provide energy)
tail - flagellum (allows sperm to swim)
ovary
produces the egg by meiosis (exocrine) and the hormones oestrogen and progesterone (endocrine)
fallopian tube
site of fertilisation
transports the egg to the uterus
uterus
holds the developing embryo during pregnancy
endometrium
site of implantation
enriched with blood vessels to nourish the embryo
forms the placenta
cervix
closes during pregnancy
vagina
holds the penis during sexual intercourse
is the birth canal
egg lifecycle once released from ovary
2 days
male infertility disorder
what: low sperm count, producing low numbers of sperm
cause: low hormone levels, genetically inherited, smoking
treatment: hormone treatment, assisted reproductive technology
female infertility disorder
what: inability to produce eggs or ovulate due to endocrine gland failure (hormonal imbalance)
cause: lack of hormones FSH and LH
treatment: hormone supplements, in-vitro fertilisation
menstrual cycle disorder
fibroids
what: benign tumours of the uterus
cause: abnormal response to oestrogen, genetically inherited
symptoms: pain, miscarriage, infertility
treatment: surgery, hysterectomy
hormones involved in menstrual cycle
follicle stimulating hormone
oestrogen
luteinising hormone
progesterone
each hormone causes the production of the hormone following it and inhibits the hormone preceding it
day 1-5
menstruation:old lining of uterus breaks down
new egg produced my meiosis
hormone FSH increases
FSH
site of production: pituitary gland
function: causes maturation of the egg by stimulating the development of the Graafian follicle which surrounds the egg
day 6-13
Graafian follicle develops
hormone oestrogen increases
oestrogen
site of production: Graafian follicle in the ovary
functions: causes endometrium to thicken and repair
inhibits the production of FSH and stimulates the production of LH
day 14
Hormone LH increases
ovulation occurs
Graafian follicle develops into Corpus Luteum (yellow body)
day 14-28
hormone progesterone increases
fertile period: days 12-16
egg dies if fertilisation does not occur, progesterone levels decrease
luteinising hormone
site of production: pituitary gland
function: stimulates ovulation
progesterone
site of production: Corpus Luteum
functions:
- maintains the endometrium during the latter part of the cycle (and during pregnancy)
- inhibits Lh production (no ovulation occurs) inhibits FSH (negative feedback, no eggs develop)
days 22-28
hormones oestrogen and progesterone levels decrease as fertilisation has not occurred:
causes endometrium to begin to break down
stimulates FSH production
