reproduction Flashcards
asexual reproduction
requires 1 parent organism
sexual reproduction
requires 2 parent organisms and the fusion of male and female gametes to form a zygote
fission
the separation of a parent into two or more individuals of approximately the same size
parthenogenesis
a process in which an egg develops without being fertilized
semelparity
single reproductive episode before death
iteroparity
multiple reproductive episodes over life span
simultaneous hermaphroditism
self-fertilisation - both gametes present
sequential hermaphroditism
protandrous: male first
protogynous: female first
Oviparity
eggs laid outside the body
Ovoviviparity
eggs hatch in mothers uterus. nutrients stored in egg
vivipartity
no eggs. embryo develops inside the mother
what are some examples of asexual reproduction
fission, budding, fragmentation and parthenogenesis
explain external fertilisation
eggs shed by the female are fertilised by sperm in the external environment
explain internal fertilization
sperm are deposited in or near the female reproductive tract, fertilization occurs within the tract
what are reproductive cycles controlled by?
hormones and environmental cues
mammalian reproduction: males
the testes consist of many highly coiled tubes surrounded by several layers of connective tissue. the tupers are seminiferous tubules where sperm form. The sperm pass into the coiled tubules of the epididymis.
what happens during ejacualtion in males?
sperm are propelled through the muscular vas deferens, the ejactulatory duct, and exit the penis through the urethra
what are the glands in the male reproductive system?
seminal vesicles, prostate gland and bulbourethral gland
Seminal vesicles
behind the bladder. Contributes about 60% of the total volume of semen
The prostate gland
Secretes its products directly into the urethra through several small ducts.
the bulbourethral gland
secretes a clear mucus before ejaculation that neutralises acidic urine remaining in the urethra
what does seman consist of ?
sperm cells
fructose and other energy sources for the sperm
acid-base buffers that create a suitable environment for the sperm
testosterone
sperm production, secondary sex characteristics and sex drive
the ovaries
lie in the abdominal cavity. each ovary is enclosed by a tough capsule and contains many follicles
what does a follicle consist of?
one egg cell surrounded by one or more layers of follicle cells
what does ovulation do?
expels the egg cell from the follicle
corpus luteum
secretes hormones depending on whether or not pregnancy occurs
estrogen
involved in ovulation and pregnancy
progesterone
prepares uterus for pregnancy
what happens if the oocyte in the oviduct is not fertilised?
the corpus luteum degenerates
what happens if fertilisation occurs?
the corpus luteum grows and continues to secrete hormones.
what does estrogen secreted by follicles and corpus luteum stimulate the growth of
the endometrium of the uterus and the production of progesterone receptors in the endometrium
why is the corpus luteum essential?
for establishing conditions that permit pregnancy and implantation
describe the acrosome reaction
when sperm makes contact with the eggs plasma membrane, it triggers a release of calcium from internal organelles starting at the point of sperm entry. Changes membrane potential of egg, prevents other sperm from fusing with egg
