Male Reproductive Tract Anatomy Flashcards
What are the characteristics of squamous epithelial cells?
Flat and wider than they are tall.
What are the characteristics of cuboidal epithelial cells?
Relatively cube-shaped.
What are the characteristics of columnar epithelial cells?
- Level nuclei.
- Ciliated, stereociliated (epididymis only), or non-ciliated.
- Absorption, movement, etc.
What are the major components of the male reproductive tract?
- Penis: Delivery system.
- Accessory sex glands: Produces seminal plasma.
- Spermatic cord: Transport duct, pampiniform plexus.
- Testis: Main sex organ, produces sperm, produces testosterone.
- Excurrent duct system: Brings the sperm to the accessory glands and out through the penis.
- Scrotum: The skin and muscle surrounding the testis.
*PASTES
What occurs during the first step of spermatogenesis?
- Called high-speed manufacturing.
- 35,000-200,000 sperm are produced every second.
- Testes must be kept slightly below body temperature.
- Sperm are non-motile and infertile.
- Occurs in testes.
What occurs during the second step of spermatogenesis?
- Called the finishing shops.
- Sperm finish maturing in the head and body epididymis (membrane changes, motility, flagellar and nuclear stabilization, and cytoplasmic droplet translocation).
- Fluid absorption.
- Stored in the tail of the epididymis. Motile and fertile.
- 8-25 billion sperm.
What occurs during the third step of spermatogenesis?
- Called warehouse and shipping.
- Stores 10-50 billion sperm (about 5-10, sometimes 12, ejaculations).
- Stored in the tail of the epididymis.
- Released when nervous stimulation triggers smooth muscle contractions.
What occurs during the fourth step of spermatogenesis?
- Called final alterations and packing.
- Occurs in the pelvic urethra.
- Vas deferens moves the sperm to the pelvic urethra to mix with accessory sex glands (Prostate, seminal vesicles, bulbourethral gland) secretions.
- The secretions contain metabolic substrates and surface coatings to protect the sperm.
- Sperm is now semen.
What occurs during the fifth step of spermatogenesis?
- Erection.
- Protrusion.
- Emission.
- Ejaculation.
What is the process of erection?
The penis becomes firmer and elongates—parasympathetic nervous system stimulation originating from the spine.
“Point”.
Species-dependent and unconscious.
What is the process of protrusion?
When the penis protrudes from the sheath due to the elongation occurring during the erection process. Occurs simultaneously with an erection.
What is the process of emission?
Seminal plasma is secreted from the accessory sex gland(s). Sperm moves from the tail of the epididymis to the pelvic urethra.
What is the process of ejaculation?
Expulsion of semen through the penile urethra-parasympathetic nervous system stimulation.
“Shoot”.
What is semen?
When sperm/spermatozoa mix with seminal plasma.
Which accessory sex gland always appear in pairs?
Seminal vesicles.
Why is the gubernaculum important?
It anchors the testis and the epididymal tail to the scrotum. This helps prevent overheating of the testicle, reascending of the testicle, and testicular torsion.
What is the function of the cremaster muscle?
The skeletal muscle that raises and lowers the testis.
What is the function of the vas deferens?
To carry the sperm from the tail of the epididymis to the pelvic urethra.
Where is the excurrent duct system located?
Between the seminiferous tubules and the epididymis.
At what temperature is spermatogenesis optimized?
4-6 degrees below body temperature or 31-35 degrees Celcius.
What are the structures involved in testicular thermoregulation?
- Pampiniform Plexus (PPP).
- Tunica Dartos.
- Scrotal Skin.
- Cremaster Muscle.
Why is it best to store the sperm as far away from the body as possible (tail of the epididymis)?
Keeping the sperm as cool as possible keeps their metabolism low, which prevents harmful metabolic byproducts from being released and altering the pH of the sperm.
What three types of tissue are found in the spermatic cord?
- Lymphatic.
- Nervous.
- Vascular.
What acts as the heat exchanger in the spermatic cord?
PPP.
What muscle is housed in the spermatic cord?
The cremaster muscle.
What is the pampiniform plexus (PPP), and what is its function?
An elaborate intertwining of testicular arteries and veins that allows for the counter-current exchange of T and heat.
The testicular veins surround the arteries bringing blood from the body.
How does the counter-current exchange of heat work in the PPP?
As the blood in the arteries flows down to the testicles, cooler blood from the testicles flows toward the body via testicular veins. As the two types of vasculature pass each other, the temperature difference causes the heat from the arterial blood to be absorbed by the vein blood. This cools the arterial blood to a temperature appropriate for spermatogenesis, and the vein blood moves the heat away from the testicles.
How does the counter-current exchange of T work in the PPP?
T being brought to the body by testicular veins as they pass by testicular arteries that contain a lower concentration of T than the testicular veins. This difference forms a concentration gradient that leads to the diffusion of T from the testicular veins into the testicular arteries (high concentration to low concentration). This allows the testicles to maintain a high concentration of T, allowing for normal function.
How does the scrotal skin contribute to the thermoregulation of the testes?
The scrotal skin contains temperature sensors that send messages to the CNS when the testes need to be raised or lowered. The message from the CNS causes the directional movement of the tunica dartos.
What happens when the temperature is too cold for the testes?
The tunica dartos contracts and pushes the testis toward the body. The scrotal skin wrinkles, decreasing its SA and blocking many sweat glands.
What happens when the temperature is too hot for the testes?
The tunica dartos relaxes and allows the testicles to move away from the body. The scrotal skin smoothes, increasing surface area and exposing sweat glands.
What direction does the tunica dartos contract?
Directionally from the bottom up.
What are the characteristics of the cremaster muscle?
- Located in the spermatic cord.
- Composed of striated muscle.
- Attaches to the parietal tunica vaginalis.
- Is continuous with the internal oblique muscle.
- Elevates the testes for short periods during excitement or fear.
- When it contracts, it limits blood flow through the pampiniform plexus. This aids in thermal regulation. (Helps keep the testes cool because they are near the body?)
What are the characteristics of the tunica dartos?
- Located in the scrotal sac.
- Composed of smooth muscle.
- Androgen dependent (T and Dihydrotestosterone or DHT).
- Sustained contraction(s).
Why are the testes the primary sex organ?
They produce male gametes and primarily T (some DHT as well).
What are the layers of the scrotum from outermost to innermost?
- Parietal Tunica Vaginalis.
- Visceral Tunica Vaginalis.
- Tunica Albuginea.
What are the location and function of the parietal tunica vaginalis
Surrounds the testicle and connects to the cremaster muscle. Is a sac-like connective tissue. Is folded.
What are the location and function of the visceral tunica vaginalis?
It is attached to the testis and covers the testis and the epididymis. Contains vasculature.
What are the location and function of the tunica albuginea?
Closest to the testis and projects into the testicular parenchyma. Is a white membrane.
What is the testicular parenchyma?
The functional part of the testicle that produces sperm and T.
What is the mediastinum of the testis?
A piece of connective tissue that contains the rete tubules.
What are the rete tubules?
The portion of the excurrent duct system that moves sperm from the seminiferous tubules to the mediastinum and into the head of the epididymis.
What happens to the sperm in the cauda epididymis as more sperm is produced?
It gets pushed up the vas deferens and slowly degrades along the way until it is excreted in the urine.
What is the shape of the efferent duct in the epididymis?
A tube the folds on itself over and over again.
How long does it take sperm to travel the length of the epididymis?
9-10 days.
What is proud cutting?
When a stallion is gelded in a way that leaves a portion of the epididymis behind so that the horse maintains a steady production of testosterone
What do Leydig cells produce?
T.