Flashcards in Male reproductive Deck (63):
1
Describe the relationship of the testes and scrotum
- testes are within the scrotum which allows them to reside outside of the body and be kept at a lower temperature which is required for sperm production
2
describe the descending of the testes
- occurs prior to birth
- they originate near the kidneys and move down through the abdominal cavity into the scrotum
- by 4 months of pregnancy, they have moved to the inguinal rings and are pulled downward by contraction of the gubernaculum.
- by 8 months they have almost completed their descent
3
inguinal rings
openings in the body wall that provide access to scrotal sac
4
gubernaculum
fibrous gland whose contraction pulls the testes down
5
tunica albuginea
-fibrous capsule covering the testes composed of mainly collagen with large blood vessels
-contains both fibroblasts and myofibroblasts
- septa extend from it inward and divide the testes into ~250 lobules
6
myofibroblast
contractile and subjects the seminiferous tubules to rhythmic contractions
7
seminiferous tubules
- produce sperm which is collected by a network of ducts and carried out of the testes by efferent ductules
- they are coiled within the interior of the testes within each lobule
- there are 1-4 in each lobule
8
epididymis
- efferent ductules connect to this
- proximal, highly coiled region of the sperm duct
9
ductus deferens
the sperm duct
10
vas deferens
the sperm duct
11
spermatogenesis
- production of sperm from undifferentiated cells called spermatogonia
- occurs within the tubule wall of the seminiferous tubules
12
describe spermatogenesis
Spermatogonia are located at the periphery of the seminiferous tubules and undergo repeated mitotic division to assure continuous supply of sperm. They will eventually enter meisos and begin moving toward the tubule lumen. When finished they are haploid and called spermatids. They are located within the inner surface of the tubule wall and project into the lumen. They must still undergo morphological changes to become sperm or spermatozoa.
13
where are spermatogonia at the beginning of spematogeneis?
near the tubule periphery
14
where are spermatognia at the end of spermatogenesis?
near the tubule lumen
15
spermatids
haploid cells formed by meiosis during spermatogenesis. Must still undergo morphological changes prior to becoming sperm
16
spermatozoa
the end product of spermatogenesis
sperm
17
Sertoli cells
- support and nourish the developing sperm
a. Partially enclose developing sperm and move them toward the tubule lumen
b. They mediate the exchange of nutrients
c. Secrete factors that mediate spermatogenesis
d. Secrete fluid into the tubule lumen
c. Phagocytosis of discarded sperm cytoplasm
18
Describe the factors secreted by Sertoli cells that impact spermatogenesis
-androgen binding protein
-traps testosterone within the epithelium
-it is required to initiate and maintain spermatogenesis
19
spermiogenesis
formation of mature sperm
20
process of spermiogenesis
1. Chromatin within the nucleus becomes very compact and the nucleus decreases in size
2. The nucleus then assumes a thin pointed shape which streamlines the sperm to facilitate swimming
3. Most organelles degenerate
4. Mitochondria remain and become localized within the middle piece of mature sperm – provide ATP needed for swimming
5. Flagellum begins to grow from the centriole located behind the nucleus forming a long tail in the mature sperm
6. Most of the cell cytoplasm is shed
7. The streamlined sperm is released into the lumen of the seminiferous tubule
21
Leydig cells
i. Secrete testosterone
ii. Lie within the connective tissue between seminiferous tubules
22
rete testes
1. Network of ducts which collects sperm produced by the seminiferous tubules
2. It is within the testes connected to the many seminiferous tubules within the testicular lobules
3. All seminiferous tubule converge in the rete testis region
23
histology of rete testes
4. Consists of thin channels lined by simple, cuboidal epithelium with a single cilia on each epithelial cell
24
efferent ductules
1. Connected to the epididymis
2. Drain the rete testis and transport sperm out of the testes into the epididymis
3. Sperm not yet mobile, will acquire the ability to swim once through the epididymis
25
histology of the efferent ductules
1. Epithelium is columnar with cilia on the tall cells and microvilli on the shorter cells
2. Surrounded by smooth muscle which contract to aid in moving the sperm through
26
Describe the path of sperm from the seminiferous tubules to the urethra
i. Sperm are produced in the seminiferous tubules
ii. The rete testis collects the sperm from the seminiferous tubules
iii. The efferent ductules drain the rete testes and transport the sperm to the epididymis
iv. Sperm undergo final maturation in the epididymis to obtain mobility
v. the epididymis contracts to move sperm towards the sperm duct
vi. the sperm duct emerges from the epididymis and passes through the inguinal ring to enter the body cavity
vii. the distal end of the duct expands before its junction with a duct from the seminal vesicle
viii. the sperm duct ends in an ejaculatory duct
ix. the ejaculatory duct passes through the prostate gland to enter the urethra
27
where are sperm produced?
the seminiferous tubules
28
what collects the sperm from the seminiferous tubules?
rete testes
29
what drains the rete testes and transports sperm to the epididymis
efferent ductules
30
where do sperm undergo final maturation to obtain mobility
epididymis
31
mucosa of the epididymis
i. Smooth muscle which is thin the proximal part and become thicker in the distal region
ii. Innervated by nerves of the autonomic nervous system
iii. Epithelium is tall, pseudostratified with long microvilli protruding into the lumen
32
how does the structure of the epididymis relate to its function
1. Microvilli absorb liquid that accompanied the sperm from the testes
2. Smooth muscle contracts to move the sperm towards the sperm duct. The thicker distal region creates stronger force to expel the sperm during ejaculation
3. The nerves control ejaculation
33
compare the sperm duct structure to that of the epididymis
1. Thick walled tube with 3 layers of smooth muscle
a. Inner and outer longitudinal
b. Center circumferial
c. Contract strongly to expel sperm
2. Relatively small lumen compared to diameter of the duct
3. Folded epithelium and lamina propria to allow expansion and contraction during ejaculation
a. Epithelium is pseudostratified and similar to epididymis
ii. The sperm duct has additional muscle layers
34
major differences between sperm duct and epididymis
- extra layers of muscle in duct
- relatively small lumen in duct
35
what are the regions of the male urethra?
prostatic
penile
36
where is the prostatic urethra
within the prostate
37
where is the penile urethra
within the penis
38
what are the male exocrine glands
- prostate
- paraurethral
- bulbourethral
39
prostate glands
- ducts enter the urethra
- secretions form 50% of seminal fluid volume
40
paraurethral glands
- secrete lubricating fluid
- enter into the lumen of the urethra
41
bulbourethral glands
- open into the urethra at the base of the penis
- secrete clear, viscous pre-ejaculate
42
describe the function of the secretions of bulbourethral glands
- lubricates the urethra
- flushes out any remaining urine
- neutralized the acidity of urine
43
lumen of seminal vesicles
- convoluted or honeycombed in cross section
- thin mucosal bridges appear to cross the lumen
44
mucosa of seminal vesicles
- highly folded interior with many out-pockets which greatly increase the surface area
- the folds bear additional small folds
- thin mucosal bridges cross the lumen
- the surface is secretory pseudostratified epithelium supported by small amount of connective tissue
- muscle surrounds and extends inward beneath the mucosa to allow contraction during ejaculation
45
secretion of seminal vesicles
yellowish, viscous liquid...
a. Contains fructose and vit C to nourish sperm
b. Is alkaline to neutralize acidity of the female vagina
c. At least 50% of semen volume is from the seminal vesicles
46
What makes up semen volume
- secretion from...
- seminal vesicles
- prostate glands
47
What are the zones of the prostate gland
- central
- transitional
- peripheral
48
central prostate gland
surrounds the ejaculatory ducts
49
transitional prostate gland
surrounds the urethra
50
peripheral prostate gland
the region of the gland not around the urethra or ejaculatory ducts
51
what are the tissue of the prostate
- glands
- stroma
52
glandular tissue of the prostate
1. Branched tubulo-acinar glands
2. Secrete thin, milky liquid
53
secretions of the prostate glands
a. Contains citric acid and enzymes that liquidfy the coagulated semen aften it has entered the vagina
b. Glycoproteins form masses within the glands that calcify into prostatic concentration which increases with age
54
stroma tissue of the prostate gland
1. Mix of collagen and smooth muscle fibers
2. Contract during ejaculation to expel fluid from the glands into the urethra
55
benign prostatic hyperplasia
1. Occurs when transitional zone enlarges
2. Causes an enlarged prostate which presses on the urethra and constricts it making urination difficult
3. Due to increased size and distension of secretory units
56
prostatic cancer
1. Occurs in the peripheral zone
2. Enlarges the prostate and can constrict the urethra
3. Malignant tumors of glandular tissue
4. Early stages are treatable – almost 2/3 are slow growing and non-aggressive
5. 1/3 are rapidly growing and shed cells which enter the lymph vessels and spread and are life threatening
57
urethra
1. central within the corpus spongium
2. terminates as a slit within the meatus
58
paraurethral glands
1. surround the urethra
2. secrete lubricating fluid into the lumen during ejaculation
59
corpus spongium
1. erectile tissue
2. surrounds the urethra and forms the glans region at the penis tip
60
corpus cavernosum
1. erectile tissue
2. two large masses above the corpus cavernosum
61
helicine arteries
1. within the erectile tissue
2. supply blood to the sinuses
62
blood sinuses
1. within the erectile tissue
2. become engorged with blood during an erection
63