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52 terms

Reproduction

STUDY
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Spermatogenesis
the process of making sperm
Parts of sperm (3)
Head (Caput)- contains nucleus
Body (Corpus)- mitochondria
Tail ( Cauda)
Acrosome
Membrane bound sac around the head of a sperm
-bag of enzymes that digest its way around the egg so it can get in
Sperm
motile cell that delivers genetic material to an egg
Testis functions
1. gametogenisis- production of gametes(sperm & ~egg)
2. endocrine: MALE: testosterone FEMALE: Progesterone & Estradiol (estrogen)
Scrotum
-holds the testis
-very muscular
-the muscles can help regulate temperature
Inguinal Canal
area in scrotum above the testis
Testis tissues
1. Interstitial tissue
2. Seminiferous tubules
testis descent
when the testis decend after fetal development
Cryptorchidism
-1% of children
-when the scrotum doesnt drop out and stay in the kidney area
-CANNOT create sperm here
-more likely to get testicular cancer
-hormone production can still occur
Interstitial tissue
-contains arteries, lymphatics, and nerves
-contains the Leydig cell
leydig cell
specific cell that produces testosterone
-Pituitary controls
seminiferous tubules
tissue within the testis
-they are looped in a messy fashion
-they have 2 ends and open up to top clear spaces structure(Rete testis)
epididymus
like an extention to the seminiferous tubules
-has head(Caput), body(), and tail(Cauda)
-sperm takes 1-2 weeks to travel from head to tail
-absorbtion of fluids here
-secretion of exocrine
What happens if you tie off tubules?
-testis expand to 3x normal size
-creates a back pressure of fluids » the pressure will eventually stop sperm production » testis will shrink to 1/3 of its original size
Cauda epididymus
resivoir for sperm
-sperm here are motile and capable of fertilization
Vasa Efferenta
connects rete testis and Caput epididymus
-efferent duct
-absorb fluid (70-90%) thickness
Efferent Duct Ligation (EDL)
-will stop producing sperm
-similar to vasectomy
prostate
little ducts that secrete into the urethra
-provides energy source for sperm
Vas Deferens
sperm goes through if ejaculation occurs
Vasectomy
-vas deferens are tied off
-dont get build up pressure
-the sperm is instead reabsorbed into body through caput epdidymus
accessory sex organs require ______?
all require testosterone or else will not function or maintain
Heat treatment
stop sperm produciton
Vitamin deficiency
stops sperm production
pampiniform plexus
mixture of veins and arteries
seminal vesicles
bulk of fluid in semen comes from here
How many days does it take to make sperm in a human?
64 days
when does sperm production start?
at puberty
How far into fetal development are germ cells produced?
6-6.5 weeks
Fetal testis charecteristics
-enormous embryonic cells (not temperature sensitive) dispersed throughout
-doesnt have lumen
-testis is called a sex cord
-The 'enormous embryonic cells' can be called: 1. Gonocytes 2. premordiol cells 3. pre-spermatogonia
embryonic cells at puberty:
they divide and form smaller cells
-they are now referred to as spermatogonia and are always found on the outer rimof the testis
spermatogonia
[2N] [mitosis]
refers to the first 4 generations in sperm development
Intermediate spermatogonia (In)
[2N] [mitosis]
-5th generation in sperm development
at A4 division, nucleous starts to look different
Primary Spermatocyte
[2N] [Meiosis] [64]
- 7th generation in sperm development/ forms after 6th division
Secondary Spermatocyte
[N] [Meiosis] [128]
-8th generation in sperm development/ forms after 7th division
-these are only around for a few hours!!
-goes on to "Reduction Division"
Spermatids
[N] [Meiosis] [256]
-9th generation in sperm development/ forms after reduction divsion
Reduction Division
7th and 8th division (Meiosis)
(primary spermatocyte » spermatids)
Spermatogenesis
the process from 1 diploid cell to sperm
-takes place outside of the lumen
Spermiogenesis
When the speramtids transform from simple cells looking to resembliing an actual sperm
Spermatizoa
Sperm that has at least entered the lumen
LeBlond theory
(theory explaining how you get a continuous production of sperm)
STEM CELL RENEWAL
"Only 7/8 goes from A4 generation to In generation, the other 1/8 goes back to being A1 generation"
Incomplete cytokinesis
when one cell divideds you get complete division of the nucleous, but only partial division of the cytoplasm
Cell differentiation between the boundary tissue and the lumen
there will be 4 layers
-the outside layer is always going to be Spermatogonia
-the next layer medialy will always be Spermatocytes
-the next layer medialy to that will either be spermatocytes OR spermatids
-the last layer next to the lumen will always be Spermatids
1. Lumen
2. Boundary Tissue
3. Simple cell
4.Spermatid
1. Tail
2. Mitochondria
3. Head
4. Acrosome
1. Spermatogonia
2. Spermatocytes
3. Spermatids
1. Testis
2. Cauda epididymus
3. Vas Deferens
4. Seminal Vesicles
5. Prostate
6. Penis
7. Urethra
1. Testis
2. Seminiferous tubules
3. Rete Testis
4. spermatid
5. Vasa Efferenta
6. Caput epididymus
7. Corpus epididymus
8. Cauda epididymus
1. Scrotum
2. Testis
3. Inguinal canal
Ways to stop sperm production
1. Heat
2. Vitamin deficiency
3. Efferent duct ligation (EDL)
4. Cryptochidism
5. X-ray
Regulation od LH [pic]
negative feedback!!
Regulaion of FSH [pic]
Negative feedback!!