Chapter 4 - Reproduction & Development Flashcards
Gonadotropin Releasing Hormone (GnRH)
released from hypothalamus, signals anterior pituitary to release gonadotropins: LH and FSH
Luteinizing Hormone (LH)
travel to gonads
Follicle Stimulating Hormone (FSH)
travel to gonads
Spermatozoa
male germ cells
Ova
female germ cells
Spermatogenesis
production of sperm, requires temp lower than that of body temperature
Seminiferous Tubules
convoluted tubules that contain spermatogenic cells
Leydig Cells
interstitial cells that synthesize testosterone from cholesterol
Sertoli Cell
testosterone binds to a specific receptor and is converted to a compound called dihydrotestosterone (dHT)
Spermatogonia
they have 46 chromosomes, reside towards basement membrane, divide by mitosis
Inhibin
acts as a negative modulator of the anterior pituitary
What happens when testosterone is too high?
Feedback mechanism will decrease the levels of LH
What happens when levels of dihydrotestosterone are too high?
increase in inhibin synthesis, which results in a decrease in levels of FSH
Secondary Oocyte
has 23 chromosomes
Follicular Phase
developing time period, lasts up to 14th day of woman’s monthly cycle
Zona Pellucida
membrane surrounding the primary oocyte
Granulosa cells
analogous to Sertoli cells in male
Theca cells
analogous to Leydig cells in male, convert cholesterol to testosterone—diffuses into follicle cells where it’s converted to estrogen
Antrum
formed by fluid building up in primary follicle
LH Surge
this surge causes the primary oocyte to undergo first meiotic division
Corpus Luteum
produce estrogen and progesterone
Luteal Phase
point of ovulation (about 14th day) until the beginning of menstrual flow
Chorionic Gonadotropin (CG)
synthesized by placenta, stimulates the corpus luteum to make estrogen and progesterone—one of the best pregnancy tests is to see if CG is present in blood
Coelom
body cavity, divided into upper thoracic cavity and lower abdominal cavity
What are the stages of development?
- Fertilization
- Cleavage (of zygote)
- Gastrulation (formation of 3 germ layers)
- Neurulation - formation of nervous system
- Neural Crest Formation
- Organogenesis
Blastomeres
the individual cells involved in growth/cleavage of zygote in half. cleaves 5 times to get a morula (32 cells)
Morula
a small, solid ball of cells
Gastrula
means gastrulation has already taken place
What are the 3 cell layers during development?
Ectoderm, mesoderm, and endoderm
Ectoderm
developmental fate, differentiates into skin, lens of eye, brain, nervous system
Mesoderm
notochord, heart, skeleton, muscle, and outer coverings of internal organs, and reproductive organs
Endoderm
inner lining of digestive tract and respiratory tract, major glands of body like liver and pancrease
What is the neural plate?
mass of ectodermal cells superior to notochord, plate will begin to fold in on itself and form the neural groove, edges of plate fuse and become neural tube
