Histology: Male Reproductive System Flashcards
What is the main function of the reproductive system?
to perpetuate the species
What is the main role for males in reproductive system?
to produce sperm and deliver to females
What is the male gamete?
sperm
What is the essential organ of the reproductive system?
gonads
males: testes
females: ovaries
What do gonads do?
produce germ cells (gametes) that have only half the number of normal chromosomes as other body cells
How many chromosomes do gametes have vs. other body cells?
gametes are haploid (1n) = 23 chrom.
normal body cells = diploid (2n) 46 chromosomes
What are the four components of the male reproductive system?
- Testes
- Passageways
- Accessory Glands
- Penis
What do the testes do?
Four components of male reproductive system:
- Testes
- Passageways
- Accessory Glands
- Penis
produce germ cells (gametes = sperm in males)
What are the 6 passageways?
Four components of male reproductive system:
- Testes
- Passageways
- Accessory Glands
- Penis
- Straight tubules
- Rete testis
- Efferent ductules
- Ductus epididymis
- Ductus deferens (aka vas deferens)
- Ejaculatory duct
6 urethra
What are the 3 glands?
Four components of male reproductive system:
- Testes
- Passageways
- Accessory Glands
- Penis
- seminal vesicles
- prostate glands
- bulbourethral glands
What is the penis?
Four components of male reproductive system:
- Testes
- Passageways
- Accessory Glands
- Penis
male copulatory organ
What are the male gonads?
the testis
Do the testis have endocrine or exocrine function?
Both
What is the endocrine function of the testis?
(reminder: testis have both endocrine and exocrine fxn)
endocrine = produce androgens, primarily testosterone through process called steroidogenesis
What is steroidogenesis?
process through which testis produce androgens (*mostly testosterone) = endocrine function
What androgen do testis produce?
testosterone
this is the endocrine function of testis through process of steroidogenesis
What is the exocrine function of testes?
spermatogenesis
sperm production
What are spermatozoa?
Sperm
What are the three steps to spermatogenesis?
- Spermatogonial phase
- Spermatocyte phase
- Spermatid phase
What is the spermatogonial phase of spermatogenesis?
first phase of spermatogenesis
speramatogonia undergo mitosis; spermatogonia turn into spermatocytes
What is the spermatocyrte phase of spermatognesis?
second phase of spermatogenesis
spermatocytes undergo meiosis (I and II); spermatocytes turn into spermatids
What is the spermatid phase of spermatogenesis?
third phase of spermatogenesis
maturation process
where spermatids turn into spermatozoa
What is the spermiogenesis phase of spermatogenesis?
third phase of spermatogenesis
this is another name for spermatid phase of spermatogenesis (turns spermatids into spermatazoa via maturation process)
Which phase of spermatogenesis turns spermatogonia –> spermatocytes?
spermatogonial phase (first phase)
Which phase of spermatogenesis turns spermatocytes –> spermatids?
Spermatocyte phase (second stage)
Which phase of spermatogenesis turns spermatids –> spermatozoa?
Spermatid phase aka spermiogenesis phase (third phase)
How long does spermatogenesis take? What is the quantity of the end result per day?
74 days
300million sperm cells produced each day
What does the maturation process of the spermatid phase include in spermatogenesis?
- formation of acrosome
- flattening of nucleus
- re-rocanization of mitochondria
- condesnation and elongation of body
- development of flaggelum
- loss of most of cytoplasm
What is spermatocytogenesis?
Spermatogonial phase and spermatocyte phase together (first two phases together)
aka spermatogonia –> spermatid
Where are the male gonads located?
male gonads = testes
located in the scrotum
Why are the male gonads located in the scrotum?
male gonads = testes
scrotum = outside abdominopelvic cavity so temperature is 3degrees lower than body temperature
lower temperature is required for spermatogenesis
Where two male gonads develop and what happens to male reproductive system if they do not end in the correct definitive position?
Male gonads = testes develop in retroperitoneal position in abdominal wall
descend to scrotum = definitive position
if do not descend = cannot produce functional sperm due to higher temp in abdominopelvic cavity
What is the tunica vaginalis? Where is it found? Where is it from?
serous membrane derived from peritoneum and obtained on testes during testes descent
has visceral and parietal layer - found on anterior and lateral sides of each testes
What is the tunica albuginea?
dense connective tissue capsule surrounding each testis
What is the mediastinum testis? Where is it?
thickened portion of the tunica albuginea on posterior side of testis
What occurs at the mediastinum testes? What is housed there?
rete testes is housed there
this is where blood vessels, lymph vessels, and ducts enter and exit testes
What are testicular lobules?
pyramidal compartments created by fibrous incomplete septums coming off of tunica albuginea
How many testicular lobules are in each testes?
250 in each testes
What is within each testicular lobule?
1-4 seminiferous tubules and loose connective tissue (rich in blood vessels, lymph vessels and leydig cells)
What are seminiferous tubules?
convoluted tubules where spermatozoa are produced
How many seminiferous tubules are in each testicular lobule? How many seminiferous tubule are in each testes?
1-4 seminiferous tubule in each testicular lobule
240-1000 in each testes
bc 1-4 per lobule, 250 lobules per testes = 240-1000 SF in each testes
How large are seminiferous tubules? diameter and length
150-250um diameter
50cm in length
What are straight tubules? Aka ____
aka tubuli recti
Each seminiferous tubule leads into a straight tubule
What are rete testis?
epithelial lining of anastomosing channels found in mediastinum testes
What are efferent ductules?
Connect rete testis to head of epididymis
What cells line seminiferous tubules?
Spermatogenic cells (different cell types depending which phase of spermatogenesis it is in)
What epithelium lines seminiferous tubules?
complex stratified epithelium
composed of two cell populations
What are the two cell populations found in seminiferous tubules?
- Sertoli cells
2. Spermatogenic cells
Sertoli cells aka ____
sustentacular cells
What are sertoli cells? Where?
supporting cells in the seminiferous tubules
What shape are sertoli cells outline and nucleus?
columnar or pyramidal shaped cells in seminiferous tubules
nucleus is elongated & triangular
prominent nucleolus (helps in identification)
What is the role of sertoli cells?
Sertoli cells create a blood-testis barrier (physical barrier preventing autoimmune attacks of spermatogenic cells)
they help support, protect and provide nutrition to the developing spermatogenic cells
^AKA SUPPORTING CELLS
Where within the seminiferous tubules are the sertoli cells?
Sertoli cells extend from basal lamina from outside of duct to the center of the duct
They extend the full thickness of seminiferous epithelium
What is the outline of sertoli cells?
indifferent outline with extensive apical and lateral processes because they largely envelop the spermatogenic cells with which they have cell junctions
Do sertoli cells have endocrine or exocrine function?
both.
Endocrine = hormones Exocrine = produce fluid for seminiferous tubules
What to sertoli cells do to excess cytoplasm?
phagocytosize excess cytoplasm
What amount of layering in the seminiferous tubules is made up of spermatogenic cells?
4-8 concentric layers of cells
What are the 4 types of spermatogenic cells found in the seminiferous tubules?
- Spermatogonia
- Primary Spermatocytes
- Secondary spermatocytes
- Spermatids
What are the physical properties of spermatogonia cells within the seminiferous tubules?
lie on basal lamina
small, rounded nucleus
~12um in diameter
don’t need to identify 3 different types of these in histological slides but know there are 3 types: type a dark, type a pale, type b
What are the 3 types of spermatogonia cells in seminiferous tubules?
Do we need to differentiate these three on histological slides?
- Type A dark / Ad spermatogonia
- Type a pale / Ap spermatogonia
- Type b spermatogonia
Do not need to differentiate on histological slides
Describe type a dark cells.
Type a dark / Ad spermatogonia
have ovoid nucleus that stain intensely basophilic (ie dark)
stem cells which give rise to two Ad spermatogonia or two Ap spermatogonia through mitosis
(can lead to self-renewal)
Describe type a pale cells.
Type a pale / Ap spermatogonia
ovoid nucleus with lightly staining/finely granular chromatin
connect to each other through cytoplasmic thin bridges (intercellular bridges) through all mitotic/meiotic divisions until spermatids through incomplete cytokinesis
allows for synchronis development
type a pale developes into type b spermatogonia (committed to go thru differentiation)
Describe type b spermatogonia
spherical nuclei with chromatin that is condensed into large clumps in a central nucleolus
What do primary spermatocytes develop from?
type b spermatogonia
because type b go through final mitotic division and their daughter cells grow in size to produce primary spermatocytes
What divisions occur with primary spermatocytes?
replicate DNA and enter meiosis I
46 chromosomes (2n) with 2 copies of each chromatid
What is the largest spermatogenic cell?
primary spermatocytes
Which stage of meiosis do primary spermatocytes arrest in?
primary spermatocytes arrest in prophase of meiosis I - this is most likely see in seminiferous cross sections
What happens with primary spermatocytes finish meiosis I?
eventually, meiosis I is completed and homologous chromosomes separate
Now: smaller haploid cells with 2 chromatids (secondary spermatocytes)
What division occurs in secondary spermatocytes?
meiosis II where chromatids separate
occurs quickly
short lived so you often don’t see them in seminiferous cross section
When are spermatids formed?
when meiosis II is completed in secondary spermatocytes
How many chromosomes do spermatids have?
23 chromosomes. haploid
What are the two types of spermatids? What is the difference?
types: early and late
early: more rounded, approx. 7-8um diameter with highly condensed chromatin
late: apparent head with acrosomal cap and flaggelum
What do you see in a cross section of a human seminiferous tubule vs a rodents ST?
rodents cross section will all be at the same stage of seminiferous tubule process
in humans stages are irregular. one cross section may show two/three different stages
- the arrangement of spermatogenic stages is patch-like and random
Trace the path of spermatozoa from seminiferous tubules outward.
Seminiferous tubules -> straight tubules (tubuli recti) -> rete testis -> efferent ductules
What are the two intratesticular ducts?
- straight tubules (tubuli recti)
2. rete testis
What are straight tubules? What are they lined with?
intratesticular ducts
aka tubuli recti
short straight tubules lined with only sertoli cells
at very end they switch to cuboidal epithelium with underlying dense connective tissue
What are rete testis? What are they lined with?
intratesticular ducts
interconnected network of channels lined with cuboidal epithelium or columnar epithelium (or even simple squamous) with underlying dense CT
epithelial cells have single apical cilium and a few short apical microvilli
Each rete testis leads to _____
about 20 efferent ductules
What are efferent ductules?
Leave the testes and enter head of epididymis
They carry sperm to the duct of the epididymis
What are efferent ductules lined with?
psuedostratified columnar epithelium with groups of non-ciliated cuboidal cells with microvilli alternating with groups of taller ciliated cells
some circularly oriented smooth muscle cells can be found around these ducts
Ductus epididymis what is it lined with?
*highly coiled
lined with psuedostratified columnar epithelium composed of rounded basal cells and columnar cells with stereocilia (known as principal cells)
surrounded by smooth muscles
How long is the ductus epididymis?
4-5 meters
What occurs in the ductus epididymis?
storage and completion of maturation process
From ductus epididymis the sperm enter ____ through what motion?
from ductus epididymis sperm enter ductus deferens through peristaltic motion during ejaculation
Ductus deferens aka ___
vas deferens
What is ductus deferens lined with?
lined with psuedostratified columnar epithelium with sparse stereocilia
muscularis has 3l ayers of smooth muscle
mucosa lies in longitudinal folds; narrow lumen and thick, muscular wall
long, straight tube which is part of spermatic cord
What are the two portions of the ductus deferens? What is the difference between them?
portions: ampulla and ejaculatory duct
ampulla: dilated area where epithelium is thicker and more folded
ejaculatory duct: portion in prostate gland; after the seminal vesicles join, no muscular layer
From ejaculatory duct, the sperm enter ____
the urethra
What are the three portions of the male urethra?
- prostatic urethra
- membraneous urethra
- spongy urethra/penile urethra
What is the difference in lining between the three portions of the male urethra?
- prostatic urethra = transitional epithelium
- membraneous urethra = stratified columnar epithelium or psuedostratified columnar epithelium
- spongy/penile urethra = psudostratified columnar with exception of distal end which is lined with stratified squamous and continuous with skin of penis
What are the male accessory glands in reproductive system? What do they do?
They produce seminal fluid, medium in which sperm leave the male body (contribute to semen)
- seminal vesicles
- prostate gland
- bulbourethral gland
Describe the seminal vesicles.
How many? Lining? What does it join with?
Two seminal vesicles (accessory glands)
highly tortuous tubular glands lined with simple columnar epithelium/psudostratified columnar epithelium rich in secretory granules
smooth muscle in inner circular and outer longitudinal arrangement
thin folds seen in lumen to increase secretory surface area
joins with ampulla of ductus deferens to form ejaculatory duct
What is responsible for most of the seminal fluid production?
seminal vesicle produce 60% of the seminal fluid
Which gland lies on the posterior wall of the urinary bladder?
seminal vesicles (2)
lie on posterior wall of urinary bladder close to terminus of ductus deferens
Which gland includes nourishing substances for sperm to promote feritlization?
seminal vesicles (2)
Describe the prostate gland.
where? what is within?
collection of 30-50 tubuloalveolar glands embedded in dense fibromuscular stroma
covered by fibroelastic capsule
contains corpora amylacea (aka prostatic concretions) - good for ID
empties in prostatic urethra
Which male accessory gland has a corpora amylacea?
corpora amylacea aka prostatic concretion
found within the prostate gland
Describe the bulbourethral glands
aka ___
lining?
where?
compound tubuloalveolar glands
lined with mucous-secreting simple columnar epithelium
located in urogenital diaphragm and empty into the proximal part of the penile urethra
What is the main function of the penis?
male copulatory organ used to deliver sperm into the female reproductive tract
What are the three cylinders of erectile tissue?
paired corpora cavernosa (2)
corpus spongiosum (1)
How does an erection occur?
when erectile tissue fills with blood
Which cylinders or erectile tissue are dorsal/ventral?
dorsal paired corpora cavernosa
single ventral corpus spongiosum
Which erectile tissue surrounds the spongy urethra?
corpus spongiosum
