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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!!

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