Male Reproductive System Flashcards
What are the functions of the male reproductive system?
1) To produce male andrgoens (sex hormones)
2) To produce, store and nourish male gamates (sex cells)
3) To introduce gamates into the female reproductive tract
Where are the testes located and what is produced inside them?
The testes are located within the scrotum. Sperm is produced within the testes and sperm will then travel through a series of ducts.
Where is the scrotum located and what is the benefit of this?
The scrotum is located just outside the abdominal/pelvic cavity. This allows for the sperm within the testes (inside the scrotum) to be stored at a temp. lower than body temp.
What muscles are responsible for determining how close the scrotum is to the body?
Cremasteric muscles
Where is the spermatic cord’s location?
Passes into the abdominal cod via the inguinal canal
What does the spermatic cord contain?
Blood vessels, lymphatic vessels and nerves
What is the function of the spermatic cord?
To suspend the testes in the scrotum
Length and width of the testes:
L: 4cm
W: 2.5cm
What are the 7 contents of the testes?
1) Blood vessels
2) Lymphatic vessels
3) Cremaster muscle
4) Cremaster artery
5) Testicular artery
6) Testicular venous plexus
7) Vas deferens
What is the function of the scrotal septum?
To seperate the scrotum into 2 compartments
What are the fasical layers that surround the testes?
1) Outer layer = Tunica Vaginalis
- Double layer
- Thin
- Derived from the peritoneum
2) Inner layer = Tunica Albuginea
- Thick
- “white coat”
- Seperates the testes into testicular lobules
How many testicular lobules does the tunica albuginea divide EACH testes?
250 - 300 testicular lobules
How many seminiferous tubules come from each testicular lobule?
1 to 4
What happens in mitosis and what is produced?
The parent cell is divided into 2 daughter (diploid) daughter cells. The daughter cells are identical to the parent and to each other.
What happens in meiosis and what is produced?
The parent cell is divided into 4 daughter (haploid) cells. These form the gametes.
Which cells undergo meiosis?
Germ cells
Where in the testes is the sperm produced?
Seminiferous tubules
What is the term used for the production of sperm?
Spermatogenesis
What cells form the walls of the seminiferous tubules and what do they secrete?
Sertoli cells secrete:
1) Nutrients that well help the development of the spermatogonium.
2) Testicular fluid - helps to transport the developed spermatids to the lumen of the seminiferous tubules.
Where are the spermatogonium cells stored?
Inside the walls of the seminiferous tubules. At the basement membrane the spermatogonium cells are immature and they will develop and become more mature the further towards the lumen of the seminiferous tubules they get.
When they are fully matured (spermatids) = they can be released into the lumen.
Where are the leydig cells located and what do they secrete?
Leydig cells are found near the capillaries and secrete androgenic steroids near the capillaries.
What % does the sertoli cells take up of the overall cells in the testes?
10%
What are the 3 substances that are contained in the testicular fluid (secreted from the Sertoli cells)?
1) Inhibin (protein hormone) = This is secreted due to a high sperm count to reduce spermatogeneisis.
2) Androgen-binding hormone = Encourages the developing sperm to bind to the androgens which will encourage spermatogenesis.
3) Mullerin - inhibiting substance
The structure of the sertoli cells?
Tall and columner
The 2 compartments of the sertoli cells?
1) Adluminal compartment
2) Basal compartment
What is the function of the tight junction that separates the 2 compartments of the sertoli cells?
It acts as a blood-testis barrier. Sperm isn’t produced at birth so the body doesn’t recognise it as a self cell. The tight junction prevents any sperm from entering the blood so that the body doesn’t carry out an immune defence on its own sperm.
Steps of the life cycle:
1) 2 multicellular diploid adults
2) Germ cells from both adults undergo meiosis to form gamates (haploid)
3) The 2 haploid gametes fuse at fertilisation
4) Zygote is formed
5) The zygote develops into the foetus via mitosis
Zygote
Fused cell which develops into the foetus
How long does it take for spermatogenesis to take place?
62-74 days
What are the 2 types of germ cells?
Type A = stay within the basal membrane of the seminiferous tubules Type B (spermatogonium) = undergo spermatogenesis
Spermatogonium
Type B germ cells (diploid) and they undergo spermatogenesis
What are the steps of spermatogenesis?
1) Spermatogonium (Type B diploid germ cells) will undergo mitosis.
2) Primary spermatocytes and formed (diploid)
3) Meiosis 1: Primary spermatocytes undergo meiosis and form 2 daughter haploid cells (secondary spermatocytes)
4) Meiosis 2: Secondary spermatocytes undergo meiosis to form overall 4 daughter haploid cells (spermatids)
5) Spermiogenesis: Spermatids develop into the mature spermatozoa.
What are the final mature sperm cells called?
Spermatozoa
In what part of the sperm’s structure are the enzymes?
Acrosome
In what part of the sperm’s structure is the genetic material?
Inside the nucleus inside the head
Why is the middle part important of the sperm’s structure?
Contains spiral mitochondria
GnRH
Gonadotropin - releasing hormone
Endocrine functions on the male reproductive system:
1) Hypothalamus releasing GnRH
2) Stimulates the anterior pituitary gland to secrete LH and FSH
What does FSH stimulate and what are the 3 effects?
Stimulates: Seminiferous tububle which then stimulates the Sertoli cells
3 effect of this:
1) Stimulates the synthesis of androgen-binding protein
2) Stimulates spermatogenesis and spermiogenesis
3) Stimulates the sertoli cells to secrete inhibin.
4) Inhibin will have a negative feedback effect on the anterior pituatory gland - to stop releasing FSH.
What does LH stimulate and what are it’s 5 effects?
Stimulates: Leydig cells.
4 effects of this:
1) Acts on the CNS.
2) Stimulates the growth of muscles and bones
3) Establishes and maintains the secondary male sex characteristics.
4) Maintains the accessory organs and glands
Stimulates: Sertoli cells (directly)
(same 3 effects as FSH)
What 3 things are involved in temperature control of the testes:
1) Heat exchange with the pampiniform plexus (a network of veins surrounding the arteries going into the testes).
2) Cremaster muscles will contract to bring the testes closer to the body (to warm them in the cold)
3) Dartos muscles will contract which wrinkles the skin which lowers the surface area of the scrotum so that less heat is exchanged with the env (in the cold)
What does the duct system do?
Allows for the mature sperm (created during spermatogenesis in the seminiferous tubules) to escape.
What is the escape route for the mature sperm out of the testes?
1) Straight tubules
2) Rete testis (gaps in between the seminiferous tubules)
3) Efferent ductules
4) Epididymis
5) Vas deferens
6) Ejaculatory duct
7) Urethra
Where is the epididymis?
Attached to the posterior surface of the testes