reproduction and embryology Flashcards
what are the male gonads called
testes
two functional components of testes
seminiferous tubules and interstitial cells
seminiferous tubules
production of sperm occurs
cells of leydig
also called interstitial cells. secrete testosterone and other androgens (male sex hormones)
sertoli cells
nourish sperm in the seminiferous tubules
where are the testes located?
in the scrotum
epididymis
as sperm mature they pass through epididymis and gain motility (flagellum) and stored
what happens during ejaculation?
sperm travels through ejaculatory duct and urethra
what is semen?
sperm mixed with seminal fluid.
seminal fluid is produced by?
seminal vesicles, prostate gland, bulbourethral gland.seminal vesicles nourish sperm with fructose and prostate gland gives the fluid alkaline properties
what is spermatogenesis and where does it occur?
formation of haploid sperm through meiosis. occurs in seminiferous tubules
spermatogonia
diploid stem cells
differentiation
process by which spermatogonia replicate genetic material and develop into diploid primary spermatocytes
secondary spermatocytes
product of first meiotic division
spermatids
product of meiosis 2
spermatozoa
after spermatids undergo maturation, they become spermatozoa
structure of sperm
head (containing genetic material) midpiece (generate energy from fructose for motility) and a flagellum or tail. sperm head is covered by a cap called acrosome - necessary to penetrate ovum
female gonads (what do they produce?)
ovaries-produce estrogen and progesterone
follicles
multilayered sacs that contain, nourish, and protect immature ova (ovaries contain thousands of follicles)
fallopian tube
one egg per month is released into peritoneal sac and then moves into fallopian tube. also known oviduct
cervix
lower end of uterus connects to vaginal canal
stages of oogenesis
- at birth, females have predifferentiated cells called primary oocytes (diploid) frozen in prophase 1.
- after menarchy (first period) one primary oocyte per month completes meiosis 1 ad becomes a secondary oocyte (plus polar body) frozen in metaphase II
- fertilization secondary oocyte completes meiosis II
- menopaus. ovaries less sensitive to FSH and LH and then atrophy
oocyte structure
surrounded by 2 cell layers (zona pellucida and corona radiata
cleavage
zygote goes through many cycles of mitosis
morula
when zygote is comprised of 8 or more cells
blastocyst
fluid filled ball
implantation
blastocyst lodges in the uterus
human chorionic gonadotropin
prevents the degeneration of corpus luteum and maintains secretion of estrogen and progesterone, if this is not produced then pregnancy will not persist beyond the fourth week
gastrula
forms after 2nd week through gastulation
ectoderm
epidermis, hair, nails epithelium of nose mouth and anal canal, lens of eye, nervous system
mesoderm
musculoskeletal system, circulatory system, excretory system, gonads, muscular and connective tissue coats of digestive and respiratory systems
endoderm
epithelial linings of digestive and respiratory tracts parts of the liver, pancreas, thyroid, bladder, and distal urinary and reproductive areas
neurulation
development of nervous system
notechord
induces the overlying ectoderm to thicken and form neural plate–eventual degenerates while a neural tube forms to become spinal cord
formation of neural tube
notecord forms and induces formation of neural folds which surround a neural groove–Neurual folds grow inward until they become tube.
neural crest cells-
Cells at the tip of each nerual fold which become peripheral nervous system
