11.2 Flashcards
(30 cards)
What is spermatogenesis?
The process of production of sperm
What is the process of the production of sperm?
Simple, round cell becomes an elaborate, highly specialised cell
Besings in outermost layer of seminiferous tubules and proceeded towards the lumen
Takes approx 65-75 days
What are the three elements of spermatogenesis?
1: mitotic proliferation: produces large number of cells
2: meiotic division: generated genetic diversity and halves number of chromosomes
3: spermatogensis: morphological change
What is the final stage of spermiogensis?
Round spermatid into elongated spermatozoa
Adapted from reading and penetrating an oocyte 300 million sperm produced per day
What are the 4 key events in spermiogenesis?
- development of acrosome (over anterior nucleus, vesicle of digestive enzymes, help sperm penetrate oocyte)
- Development of tail (sperm motility, help sperm penetrate oocyte)
- Condensation of nucleus (DNA undergoes packaging, becoming highly condensed protect DNA)
- Shedding of excess cytoplasm (taken up by Sertoli cells, streamlined sperm, mitochondria remain around tail to power mobility
How many sperm are produced for every spermatiogonium?
4 sperm
Begins at puberty
Ends at death
What is the role of the testes?
Produce physically mature sperm that are incapable of fertilising an oocyte
What is the role of tracts (ducts)
Responsible for functional maturation, nourishment, storage and transport of sperm
What is the role of seminiferous tubules?
Site of sperm and hormone production
What is the role of the rete testis?
Network of tubules that carry sperm from the testes to the efferent ducts
What is the role of the efferent ducts?
Connect the rete tests to the epididymis
Where is the epididymis located and what does it look like?
Posterior side of the testis
7cm long tubule
Soiled and twisted to take up less space
3 segments (head, body, tail)
12-14 days for sperm to travel through the epididymis
What are the 5 functions of the epididymis?
- Monitors and adjusts the composition of fluid produced by the seminiferous tubules
- Recycling centre for damaged sperm - resort and breakdown cellular debris and damaged sperm
- Stores and protects sperm
- Concentrates sperm
- Site of functional maturation of sperm
How does functional maturations occur?
Spididymis secrets a variety of proteins that bind to sperm
This stabilises sperm so it can withstand forces during ejaculation
What does sperm maturation depend on?
Androgens
Bind to and stimulate epididymis cell
Where is the ductus deferens (vas deferens) located?
Begins at the tail of epididymis
Ascends posterior side of testis
Joints spermatic cord
Ascends though the inguinal canal into abdominal cavity
Passes along lateral surface of the bladder
Approaches superior and posterior prostate gland
End enlarges from ampulla of the ductus deferens.
What does the ductus deferens contain and how does it propel sperm along duct?
Contains a thick layer of smooth muscle
Peristaltic contractions propel sperm and fluid along duct
Where can sperm be stored for several months?
In the ductus deferens contain
What is the ejaculatory duct?
A short duct ant connects to the ampulla of ductus deferens and duct of seminal vesicle gland where sperm combine with seminal vesicle fluid.
Where is the male urethra located?
Extends from bladder to the end of penis
What are the three parts of the male urethra?
1: prostatic urethra: passes through prostate
2: membranous urethra: passes through floor of pelvis and is surrounded by external urethral sphincter
3: spongy urethra: passes through the penis
What is the function of the male urethra?
Passageway for both urine and semen
What are the three male accessory glands?
Seminal vesicles x2
Prostate
Bulbourethral glands x2
Describe the seminal vesicles
Paired vesicles
5cm long
Located posterior wall of bladder
Very active secretory glands
Contribute 60% volume of seem
Thick mucus like alkaline fluid
Neutralise acidic environment
