Male Reproductive Tract Anatomy Flashcards
1
Q
What are the characteristics of squamous epithelial cells?
A
Flat and wider than they are tall.
2
Q
What are the characteristics of cuboidal epithelial cells?
A
Relatively cube-shaped.
3
Q
What are the characteristics of columnar epithelial cells?
A
- Level nuclei.
- Ciliated, stereociliated (epididymis only), or non-ciliated.
- Absorption, movement, etc.
4
Q
What are the major components of the male reproductive tract?
A
- 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
5
Q
What occurs during the first step of spermatogenesis?
A
- 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.
6
Q
What occurs during the second step of spermatogenesis?
A
- 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.
7
Q
What occurs during the third step of spermatogenesis?
A
- 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.
8
Q
What occurs during the fourth step of spermatogenesis?
A
- 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.
9
Q
What occurs during the fifth step of spermatogenesis?
A
- Erection.
- Protrusion.
- Emission.
- Ejaculation.
10
Q
What is the process of erection?
A
The penis becomes firmer and elongates—parasympathetic nervous system stimulation originating from the spine.
“Point”.
Species-dependent and unconscious.
11
Q
What is the process of protrusion?
A
When the penis protrudes from the sheath due to the elongation occurring during the erection process. Occurs simultaneously with an erection.
12
Q
What is the process of emission?
A
Seminal plasma is secreted from the accessory sex gland(s). Sperm moves from the tail of the epididymis to the pelvic urethra.
13
Q
What is the process of ejaculation?
A
Expulsion of semen through the penile urethra-parasympathetic nervous system stimulation.
“Shoot”.
14
Q
What is semen?
A
When sperm/spermatozoa mix with seminal plasma.
15
Q
Which accessory sex gland always appear in pairs?
A
Seminal vesicles.
16
Q
Why is the gubernaculum important?
A
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.
17
Q
What is the function of the cremaster muscle?
A
The skeletal muscle that raises and lowers the testis.
18
Q
What is the function of the vas deferens?
A
To carry the sperm from the tail of the epididymis to the pelvic urethra.
19
Q
Where is the excurrent duct system located?
A
Between the seminiferous tubules and the epididymis.
20
Q
At what temperature is spermatogenesis optimized?
A
4-6 degrees below body temperature or 31-35 degrees Celcius.
21
Q
What are the structures involved in testicular thermoregulation?
A
- Pampiniform Plexus (PPP).
- Tunica Dartos.
- Scrotal Skin.
- Cremaster Muscle.
22
Q
Why is it best to store the sperm as far away from the body as possible (tail of the epididymis)?
A
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.
23
Q
What three types of tissue are found in the spermatic cord?
A
- Lymphatic.
- Nervous.
- Vascular.
24
Q
What acts as the heat exchanger in the spermatic cord?
A
PPP.
25
What muscle is housed in the spermatic cord?
The cremaster muscle.
26
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.
27
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.
28
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.
29
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.
30
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.
31
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.
32
What direction does the tunica dartos contract?
Directionally from the bottom up.
33
What are the characteristics of the cremaster muscle?
1. Located in the spermatic cord.
2. Composed of striated muscle.
3. Attaches to the parietal tunica vaginalis.
4. Is continuous with the internal oblique muscle.
5. Elevates the testes for short periods during excitement or fear.
6. 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?)
34
What are the characteristics of the tunica dartos?
1. Located in the scrotal sac.
2. Composed of smooth muscle.
3. Androgen dependent (T and Dihydrotestosterone or DHT).
4. Sustained contraction(s).
35
Why are the testes the primary sex organ?
They produce male gametes and primarily T (some DHT as well).
36
What are the layers of the scrotum from outermost to innermost?
1. Parietal Tunica Vaginalis.
2. Visceral Tunica Vaginalis.
3. Tunica Albuginea.
37
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.
38
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.
39
What are the location and function of the tunica albuginea?
Closest to the testis and projects into the testicular parenchyma. Is a white membrane.
40
What is the testicular parenchyma?
The functional part of the testicle that produces sperm and T.
41
What is the mediastinum of the testis?
A piece of connective tissue that contains the rete tubules.
42
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.
43
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.
44
What is the shape of the efferent duct in the epididymis?
A tube the folds on itself over and over again.
45
How long does it take sperm to travel the length of the epididymis?
9-10 days.
46
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
47
What do Leydig cells produce?
T.
48
What is the function of the seminiferous tubules?
To produce sperm (has a smooth muscle band underneath the basal lamina that allows for contraction).
49
What are the seminiferous tubules bound in?
The basement membrane.
50
What is the function of the Sertoli cells?
To act as nurse cells for the sperm. In the basement membrane.
51
What are the six phases of sperm creation from least mature to most mature?
1. Spermatogonium (created by mitosis).
2. Primary spermatocyte (meiosis 1).
3. Secondary spermatocyte (meiosis 1).
4. Spermatid (meiosis 2).
5. Differentiating spermatid (meiosis 2).
6. Spermatozoon in the lumen.
*Not all of the seminiferous tubules will be at the same point regarding sperm development.
52
What surrounds the basal laminae of seminiferous tubules?
Interstitial space. Contains Leydig cells.
53
What moves away from the Leydig cells?
The capillaries in the interstitial space. Feed into testicular veins.
54
What is the function of a gap junction?
Connexon proteins that make channels between cells to allow for the transport of proteins or signaling molecules between cells.
55
What is the function of tight junctions?
To form water-tight seals between cells to prevent ECM or other particles from moving past the cells.
56
What function do tight junctions perform in the testis?
They maintain the blood-testis barrier to prevent the immune system from destroying immature sperm cells. Opens to allow spermatocytes to go through tight junctions and enter the ad luminal space.
57
What stage of sperm cells are found in the ad luminal space?
Primary spermatocytes, secondary spermatocytes, and spermatids.
58
What is the proximity of Leydig cells to capillaries?
They are side-by-side.
59
What is testicular size related to?
Sperm production capability. Bigger=Better.
60
Is testicular size in relation to body weight consistent throughout a species?
Primarily.
61
What species is the exception to the rule of selecting based on fertility, no matter what the other traits are?
Horses.
62
What is the anatomy of the secondary sex organs (excluding accessory sex glands)?
Tubes with multiple layers of tissue.
63
What is the structure and function of the serosa layer?
1. Made of simple squamous epithelium.
2. Contains some connective tissue.
3. Outermost.
64
What is the order of layers of tissue in the secondary sex organs from outermost to innermost?
1. Serosa.
2. Muscularis.
3. Submucosa.
4. Mucosa.
65
What is the structure and function of the muscularis layer?
1. The layer(s) of smooth muscle between the serosa and submucosa.
2. Outer longitudinal layer that runs parallel to the tube and contracts in the same direction.
3. Inner circular layer that allows stationary contractions.
4. Moves sperm, a fetus, and oocytes.
66
What is the structure and function of the submucosa layer?
1. Layers of loose connective tissue between the muscularis and mucosa.
2. Contains support tissues: Large blood vessels, lymphatic vessels, nerves, and maybe glands.
67
What is the structure and function of the mucosa layer?
1. Lines various body cavities.
2. Innermost.
3. Ciliated or non-ciliated.
4. May have secretory cells.
68
What is the vas effrentia?
The same thing as the efferent ducts that take sperm from the mediastinum into the caput epididymis.
69
How long is the epididymis?
30-60 meters (species dependent).
70
What kind of muscle surrounds the epididymis, and what function does it perform?
1. Smooth.
2. Allows for peristaltic-like contractions to move sperm though its entire length.
71
What hormone stimulates the contractions in the epididymis?
PGF2a.
72
What hormone stimulates the contraction of the vas deferens and cauda epididymis?
OT.
73
What is the maturation function of the epididymis?
Immature and infertile sperm leaves the testis. Are exposed to fluid from rete tubules and Sertoli cells that help the sperm attain motility and fertility.
74
What is the storage function of the epididymis?
Stored in the cauda epididymis for up 60 days before they lose viability. Old sperm is pushed up the vas deferens as more new sperm is made.
75
What is the secretion function of the epididymis?
Various segments of the epididymis contribute material (proteins and lipids) to the sperm. Allows for membrane changes that lead to fertility.
76
What is the concentration function of the epididymis?
Fluid absorption of fluid from the Sertoli cells and rete tubules. Occurs in the caput epididymis.
77
What is the sperm transport function of the epididymis?
Peristaltic like contractions stimulated by PGF2a.
78
What are cytoplasmic droplets?
Remnants leftover from sperm production that slowly works its way down the sperm as it matures. Usually, detach when exposed to the seminal plasma.
79
Where is sperm at its maximal number?
In the cauda epididymis.
80
What happens to the number of sperm in the cauda epididymis if the male is bred or collected from too often?
A 25-45% sperm reduction is seen.
81
What are accumulators?
Animals that do not void dead sperm but let it collect.
82
Where is stereociliated simple columnar epithelium found?
In the caput epididymis. Function as fluid absorbers.
83
What animals have vertically oriented testicles?
Buck (goat), Buck (deer), Ram, and Bull.
84
What animals have oblique-oriented testicles?
Boar and Dog.
85
Which animal has horizontally oriented testicles?
Stallion.
86
What are the parts of the pelvic genitalia?
1. Accessory sex glands (varies by species)
2. Muscles for ejaculation and erection.
87
What is fractioned semen?
When different parts of the ejaculate that are produced in different glands are delivered separately and mixed in the cervix.
88
What two animals have fractioned semen?
Boars and Stallions (Sperm free, Sperm rich, Gel fraction).
89
What are the structure and function of the seminal vesicles?
1. Lobed in bulls and rams.
2. Empties into the pelvic urethra at the colicus seminalis.
3. Produces a significant part of the seminal plasma/semen.
4. Slightly alkaline to neutralize the acidity in the female tract.
5. Produces fructose to provide the sperm with energy.
6. Produces the gel fraction in stallions.
90
What is the structure and function of the prostate?
1. 2 shapes (both may be present).
1a. Body-protruding.
1b. Disseminate-wraps around the urethra.
2. All mammals have this.
3. Secretions vary by species.
91
What is the function of the Cowper's gland/bulbourethral gland?
1. Secretes mucoproteins to protect the sperm from residual urine in the urethra.
2. Produces the gel fraction in boars.
92
What accessory sex glands does the dog have?
1. Body prostate.
93
What accessory sex glands does the cat have?
1. Body prostate.
2. Cowper's gland/bulbourethral gland.
94
What accessory sex glands does the stallion have?
1. Seminal vesicles.
2. Body prostate.
3. Cowper's gland/bulbourethral gland.
95
What accessory sex glands does the boar have?
1. Body prostate.
2. Disseminate prostate.
3. Seminal vesicles.
4. Cowper's gland/bulbourethral gland.
96
What accessory sex glands does the ram have?
1. Seminal vesicles.
2. Disseminate prostate.
3. Cowper's gland/bulbourethral gland.
97
What accessory sex glands does the ram have?
1. Seminal vesicles.
2. Disseminate prostate.
3. Cowper's gland/bulbourethral gland.
98
What accessory sex glands does the bull have?
1. Body prostate.
2. Disseminate prostate.
3. Seminal vesicles.
4. Cowper's gland/bulbourethral gland.
99
What is the start/proximal end of the penis?
The bulb of the penis.
100
What is the crus penis?
The vasculature leading into the corpus cavernosus that allows for an erection to occur.
101
What is the ischiocavernosus muscle?
Connected to the pelvic bone and contains the crus penis. Contracts to prevent the egress/leakage of blood from the penis during an erection.
102
What is the bulbospongiosus muscle?
Contracts to force semen out of the urethra.
*May restrict blood circulation, but this is not its primary function.
103
What animals have a fibroelastic penis?
1. Boar.
2. Ram.
3. Bull.
104
What animals have a muscular vascular penis?
1. Stallion.
2. Cat.
3. Human.
105
What does the glans refer to?
The head region of the penis.
106
What is the corpus spongiosum?
The tissue in the penis that prevents the urethra from closing during an erection, allowing the semen to be ejaculated.
107
What is the corpus cavernosa?
The tissue in the penis that becomes engorged with blood to produce an erection.
I. In FE penises, the CC is used to maintain blood pressure.
II. In MV penises, the CC creates the erection of otherwise flaccid tissue.
108
What muscle do both the MV and FE penis share?
The retractor penis muscle (RPM).
109
What is the sigmoid flexure?
An s-shaped muscle attached to the FE penis that relaxes during an erection making the penis appear longer.
110
What is the function of the sigmoid flexure in animals with an MV penis?
It retracts the penis back into the sheath after mating.
111
What is unique about the glans penis of the cat?
During an erection, barbs stick out of the glans penis that are used to stimulate the vagina and cervix of the queen for the induction of ovulation.
112
What is the purpose of the os penis/baculum?
Aids in copulation.
113
What is the purpose of the bulbus glandis?
To help hold the male dog in place during copulatory lock with the bitch. Can last 5-45 minutes.
114
Which penis type has a large glans?
MV.
115
What is unique about the rooster reproductive tract?
It is located completely inside the body. The sperm is stable at body temperature.
116
Where are the testes of the rooster located?
Near the kidneys.
117
What is the function of the vas deferens in the rooster?
Sperm transport and storage.
118
What does each vas deferens open into?
The papilla, which is analogous to the penis.
119
True or False: The rudimentary copulatory organ is used for copulation.
False. It is not used for copulation.
