Reproductive System Flashcards
Sexual Reproduction
- differs from asexual reproduction in that the genetic material of two organisms combine and results in a genetically unique offspring
- occurs via the fusion of two gametes, specialized sex cells produced by each parent
What does sexual reproduction require
- the production of functional sex cells or gametes by adult organisms
- the union of these cells (fertilization and conjugation) to form a zygote
- the development of the zygote into another adult, completing the cycle
Gonads
specialized organs that the gametes are produced in
- male gonads, the TESTES, produce sperm in the tighly coiled seminiferous tubules
- The female gonads, the OVARIES, produce OOCYTES (EGGS)
Hermaphrodites
possess both functional male and female gonads,
-include the hydra and the earthworm
Gametogenesis
- the production of functional sex cells
- In males, the process is called SPERMATOGENESIS or sperm production and occurs in the seminiferous tubules of the testes
- In females, the process is called OOGENESIS, or egg production, and occurs in the ovaries
Fertilization
the union of the egg and sperm nuclei to form a zygote with a diploid number of chromosomes
Internal fertilization
- practiced by terrestrial vertebrates
- provides a direct route for sperm to reach the egg cell
- this increases the chances of fertilization success, and females produce fewer eggs
Where are the testes located?
in the SCROTUM
scrotum
and external pouch that maintains the testes temp @ 2-4 degrees celsius lower than the body temp–essential for sperm survival
What is the passageway for sperm?
- sperm passes the testes through the VAS DEFERENS, to the EJACULATORY DUCT, and then to the URETHRA
- the urethra passes through the penis until it terminates with an external opening at the GLANS of the penis
Testes
also the site of production of testosterone
testosterone
regulates secondary secondary male sex characteristics including facial and pubic hair, and voice changes
Spermatogenesis
sperm production
Where does spermatogenesis occur?
occurs at the seminiferous tubules
what does the head of the sperm consist of?
the nucleus
The purpose of the tail of the sperm
propels the sperm
What does the neck of the sperm contain
the mitochondria which provides energy for locomotion
Acrosome
- cap like structure derived from the golgi apparatus
- develops over the anterior half of the head
- contains enzymes need to penetrate the tough outer covering of the ovum
Where are the ovaries found?
found in the abdominal cavity below the digestive system
What do the ovaries consist of
follicles
follicle
a multilayered sac of cells that contains, nourishes, and protects the immature ovum
-produce estrogen
uterus
each fallopian tube opens into the upper end of a muscular chamber called the uterus which is the site of fetal development
Where is a inmature ovum drawn to when released?
is released from the ovary into the abdominal cavity and is drawn by cilia into the nearby OVIDUCT, also known as a FOLLOPIAN TUBE
Cervix
lower narrow end of the uteris
-connects with the vaginal canal
Vaginal Canal
site of sperm deposition during intercourse
-also the passageway through which a baby is expelled during child birth
Oogenesis
-the production of female gametes
where does oogenesis occur?
ovarian follicles
What are inmature ova known as?
primary oocytes–diploid cells that form by mitosis in the ovary
What surrounds the oocyte cell membrane
INNER ZONA PELLUCIDA LAYER
CORONA RADIATA LAYER (OUTER LAYER)
what does the mature ovum contain?
cytoplasm, RNA, organelles, and nutrients needed by the developing embryo
What regulates the Leteinizing hormones (LH) and follicle stimulating hormone (STH)?
gonadotropin-releasing hormone (GnRH)
Estrogen
- steroid hormone necessary for normal female maturation
- stimulate the development of the female reproductive tract, contribute to the development of secondary sexual characteristics, and influence libido
- responsible for the thickening of the endometrium (the inner lining of the uterine wall)
- secreted by the ovarian follicles and corpus Leteum
Progesterone
- a steroid hormone secreted by the corpus Luteum during the Leutel phase of the menstrual cycle
- stimulates the development and maintenance of the endometrium in prep for implantation
What are the different stages of the menstrual Cycle
- follicular phase
- ovulation
- leutal phase
- menstruation
Follicular Phase
- begins with the ending of the menstruation flow form the previous cycle
- FSH from the anterior pituitary promotes the development of the follicle, which grows and begins secreting estrogen
Ovulation
- midway through the cycle, ovulation occurs
- a mature ovarian follicle bursts and releases an ovum
- ovulation is caused by a surge in LH and is preceded by a peak in estrogen levels
How often do women ovulate
once every 4 weeks (unless pregnant or lactating) until menopause, which typically occurs between ages 45 and 50
Menopause
the ovaries become less sensitive to the hormones that stimulate follicle development (FSH and LH) and eventually atrophy
- the remaining follicles disappear
- the remaining estrogen and progesterone levels greatly decline and ovulation stops
- the profound changes in hormone levels are often accompanied by physiological and psychological changes that persist until a new balance is reached
Luteal Phase
after ovulation, LH maintains the remnant of the rupture follicle called the Corpus Leteum which secretes estrogen and progesterone
What is essential for the maintenance of the endometrium?
progesterone and estrogen
