Histology of Reproductive System Flashcards
1
Q
What is the male reproductive system responsible for?
A
- Continous production, nourishment, and temporary storage of haploid male gamete (spermatozoa or sperm)
- the synthesis and secretion of male sex hormones (androgens)
2
Q
What does the male reproductive system consist of?
A
- Testes-produce sperm and synthesize and secrete androgens
- The epididymis, vas deferens, ejaculatory duct, and a segment of the male urethra which form the duct system responsible for transport of spermatazoa to the exterior.
- The seminal vesicle and prostate gland whose secretions form the bulk of the semen and provide nutrients to ejaculated spermatozoa.
- The penis the copulatory organ, formed of erectile tissue.
3
Q
What is each testis enclosed by?
A
A tough connective tissue covering called the tunica albuginea.
4
Q
What do fibrous septa do?
A
They project into the testicular mass, dividing the tissue into 250 to 300 lobules. Each lobule contains one to four seminiferous tubules.
5
Q
How many seminiferous tubules does each lobule contain?
A
250 to 300.
6
Q
How long is each seminiferous tubule, what does it look like?
A
It is 80cm long, it is U-shaped with the two ends opening into the rete testis.
7
Q
What is the rete testis?
A
A network of channels that collect the products of the seminiferous epithelium (sperm, secretory proteins, fluid, and ions).
8
Q
What is the space in between the seminiferous tubules occupied by?
A
The abundant blood vessels and aggregates of the andorgen-producing Leydig cells.
9
Q
What are leydig cells?
A
They are androgen producing and respond to LH and produce testosterone.
10
Q
What are the cells of the seminiferous tubule central lumen?
A
It is lined by a specialized seminiferous epithelium containing:
- somatic sertoli cells
- the spermatogenic cells
11
Q
Describe the histology of sertoli cells?
A
They are columnar epithelial cells containing a light-staining nucleus with a prominent nucleolus.
12
Q
Where do sertoli cells extend from?
A
From the basal lamina to the lumen of the seminiferous tubule and are connected by tight junctions to form a basal and adluminal compartment within the tubule.
13
Q
What are tight junctions between sertoli cells components of?
A
Blood-testis barrier
14
Q
What is the function of the blood-testis barrier?
A
It protects developing spermatogenic cells located within the adluminal compartment from autoimmune reactions.
15
Q
What is the function of sertoli cells?
A
To support cells to the developing germ cells in the tubule, they phagocytize residual germ cell cytoplasm, regulate the release of mature spermatozoa and secrete androgen binding protein in response to FSH stimulation.
16
Q
What does ABP function to do?
A
It concentrates the testosterone produced by the Leydig cells in the seminiferous tubule to stimulate spermatogenesis.
17
Q
What do the spermatogenic cells include?
A
The spermatogonia, spermatocytes, and spermatids.
18
Q
Describe spermatogonia?
A
They are diploid stem cells of the testis. They have small dense oval nuclei and are closely associated with the seminiferous tubular wall within the basal compartment of the tubule.
19
Q
What do the spermatogonia do?
A
They divide by mitosis to generate two daughter cells. one daughter cell initiates a spermatogenic cell sequence (spermatogenesis). The other cell becomes a spermatogonium with self-renewing capacity and is soon able to divide and initiate another spermatogenic cell sequence.
20
Q
What do spermatogonia that enter the spermatogenesis cell sequence do?
A
They divide and give rise to primary spermatocytes (also diploid cells)
21
Q
What do primary spermatocytes do?
A
They enter meiosis I and give rise to the secondary spermatocytes (haploid cells). These cells in turn differentiate into haploid spermatids during meiosis II.
22
Q
How do you distinguish between primary and secondary spermatocytes in HandE sections?
A
TRICK QUESTION
you cant
23
Q
Describe the histology of the spermatocytes.
A
They are located away from the tubular wall with the adluminal comparment and can be distinguished by their large nuclei containing dark-staining chromatin.
24
Q
Describe the histology of spermatids.
A
They are even closer to the lumen of the tubule than speratocytes. They may be identified by their small dense dark-staining nuclei that can appear round in an early spermatids and oblong in the late spermatids.
25
What is spermatogenesis?
The process of sperm cell development. During spermatogenesis, the seminiferous epithelial cells undergo successive mitotic and meiotic divisions to produce spermatozoa.
26
What is spermiogeneisis?
The last step of spermatogenesis. Spermatids undergo a dramatic change in form during speriogenesis-into the streamline spermatozoa adapted for fertilization.
27
What does spermiogenesis involve?
Nuclear condensation, formation of the acrosomal cap, and development of a tail to ultimately form the mature spermatids that are released into the lumen of the tubule.
28
Are mature spermatids motile or immotile?
They become nonmotile sperm upon release into the seminiferous tubular lumen and are propelled to the epididymis where they undergo a maturation process resulting in the acquisition of forward motility leading to fertilization capability.
29
What is the epididymis?
A highly elongated and coiled tubules (about 6 meters in length in the adult human) where sperm mature and are stored.
30
What are the three major segments of the epididymis?
THe head body and the tail
31
Describe the histology of the epididymis?
It is pseudostratified columnar with long and branched sterocilia.
32
What does the epitheliym of the epididymis consist of (2 major cell types)?
1. Columnar principal cells, extending from the lumen to the basal lamina. The apical domain of the principal cells displays banched stereocilia.
2. Basal cells associated with the basal lamina. Basal cells are regarded as the undifferentiated precursors of the principal cells (stem cells).
33
Describe the difference in histology of the epididymis from the initial to terminal portions.
The initial portion of the epididymis are surrounded by a circular layer of smooth cells. The terminal portion (body and tail) display an increase in thickness of the inner circular smooth muscle layer and the development of an outer longitudinal smooth muscle layer.
34
What is the vas deferens?
A 45 cm long muscular tube that is continuous with the end of the epididymis
35
What is the lining of the vas deferens consist of?
pseudostratified columnar with stereocilia similar to that of the epididymis, and is supported by a connective tissue lamina propria with elastic fibers.
36
What does the muscular wall of the vas deferens consist of?
Inner and outer layers of longitudinally oriented muscle separated by a middle circular layer.
37
What does the external layer of the vas deferens consist of?
Loose connective tissue and adipose cells
38
What is the ampulla of the vas deferens?
The dialated portion of the vas deferens, it leads directly into the prostate gland.
39
What does the ampullar fuse with?
with the duct of the seminal vesicle, forming the ejaculatory ducts that pass through the prostate gland to empty secretion into the prostatic urethra.
40
What is the prostate?
The largest accessory reproductive gland.
41
What is the prostate surrounded by?
a capsule that consist of 30 to 50 branched tubuloalveolar glands that empty their contents into the prostate urethra.
42
What are the glands of the prostate surrounded by?
Smooth muscle cells and connective tissue
43
What are the three specific zones of the smooth muscle cells and connective tissue that surround the prostate glands?
1. A transition zone closest to and surrounding the prostatic urethra.
2. A central zone
3. A peripheral zone
44
What are prostate glands lined by?
A combination of simple and pseudostratified columnar epithelial cells.
45
What does the lumen of the prostate glands contain?
they contain concretions (corpora amylacea) rich in glycoproteins that are sometimes a site of calcium deposition.
46
What do the glands of the prostate produce?
A zinc-rich alkaline fluid that neutralizes the acidity of the vagina, provides nutrients and transports the sperm, and liquefies semen.
47
What is benign prostate hyperplasia (BPH)?
It is a condition that occurs with aging and is a noncancerous enlargment of the prostate gland that can restrict the flow of urine through the prostatic urethra. The cells and stroma of the periurethral central and transitional zones undergo hyperplasia in older men to produce this condition.
48
What happens of the cells and stroma of the periurethral central and transitional zones as a man gets older.
The cells and stroma of the periurethral central and transitional zones undergo hyperplasia in older men to produce this condition.
49
Describe prostate cancer.
70-80 percent originate from the main prostate glands of the peripheral zone, farthest from the urethra. Urinary symptoms are not present at the early stage and tumor growth is often detected by digital palpation of the prostate, by elevated serum levels of prostate specific antigen, or by back pain caused by vertebral metastisis.
50
What are symptoms of prostate cancer?
Urinary symptoms are not present at the early stage and tumor growth is often detected by digital palpation of the prostate, by elevated serum levels of prostate specific antigen, or by back pain caused by vertebral metastisis.
51
What are the two coexisting events of the menstural cycle?
the ovarian cycle and the uterine cycle
52
What happens during the ovarian cycle?
several ovarian follicles, each housing a primary oocyte, undergo a differentiation process (folliculogenesis) in preparation for ovulation into the oviducts or fallopian tubes.
53
What happens during the concurrent uterine cycle?
The endometriym, the lining of the uterus, is preparing for embryo implantation. If fertilization of the ovulated egg does not take place, the endometriym is shed, menstruation occurs and a new menstrual cycle starts.
54
What does the female reproductive system consist of? What does each function to do?
1) The ovaries are involved with the production of the female gamete, the secretion of estrogens and progesterone, and the regulation of postnatal growth of the reproductive organs and development of secondary sexual characteristics.
2) The oviduct, uterus, vagina, and vulva (external genitalia)
55
What is the ovary lined with?
A simple squamous-to-low cuboidal epithelium (called the ovarian surface epithelium) and a subjacent connective tissue layer, the tunica albugeinea.
56
What does the broad cortex contain?
connective tissue and primordial follicles housing primary oocytes (arrested in prophase of meiotic I).
57
What does the medulla consist of?
Connective tissue, interstitial cells, nerves, lymphatics, and blood vessels reaching the ovary through the hilum
58
What do the surface epithelial of the ovary do?
They are involved in repairing the damage caused to the surface of the ovary after each ovulation.
59
Where can cells with a characteristic stem cell phenotype be found?
On the ovary and the fimbria of the oviduct.
60
What are the characteristic stem cell phenotypes postulated to be the origin of?
some ovarian carcinomas.
61
What are the three phases of the ovarian cycle
1. follicular phase (folliculogenesis)
2. the ovulatory phase
3. luteal phase
62
What is the ovarian cycle controlled by?
Secretion of the hormones FSH (follicule stimulating hormone) and LH (luteinizing hormone) and results in the production of hormones estrogen and progesterone.
63
What is the follicular phase?
It consists of the sequential development of several primordial follicles, one of which will be ovulated. Generally one follicle completes its development, the remainder degenerate by apoptotic process called atresia.
64
What does atresia do?
It ensures that only viable follicles, containing oocytes of optimal quality for fertilization, are available throughout the reproductive period.
65
Wat doe atretic follicles do?
many remain hormonally active, thereby contributing to the endocrine function of the ovary that prepares the endometrium for implantation.
66
What are primordial follicles surrounded by?
A simple squamous layer of granulosa cells.
67
What do primordial follicles do?
They are recruited to initiate the process of folliculogenesis in response to FSH.
68
What does the primordial follicle contain?
The diploid primary oocyte arrested in prophase of meiosis I.
69
What do primordial follicles become? When does this happen?
Primordial follicles become primary follicles when the single layer of squamous ganulosa cells changes into a simple cuboidal layer of granulosa cells.
70
What do granulosa cells secrete?
Estrogen in response to FSH stimulation.
71
What separates the granulosa cells from the stroma of the ovary?
A basal lamina.
72
What is the zone of pellucida?
it separates the primary oocytes from the granulosa cells.
73
What do granulosa cells proliferate into?
A stratified cuboidal epitheliym and they continue to secrete estrogen.
A cellular shell or theca surround the follicle.
74
What layers do the theca form?
| What do these layers do?
1. The theca interna, a vascularized cell layer adjacent to the basal lamina supporting the granulosa of the follice
2. The theca externa, a fibrous layer continuous iwth the ovarian stroma.
75
What are antral follicles?
Small intercellular spaces that develop between granulosa cells. These spaces contain follicular fluid (liquor folliculi). The spaces eventually coalesce into a single space called the antrum.
76
What are the three specific regions that the fluid of the antrum segregates into?
1. The cumulus oophorous, a cluster of granulosa cells anchoring the primary oocyte to the wall of the follicl. The cumulus prevents the primary oocyte from floating freely in the antrum fluid. it is also the nutrient delivery channel to the primary oocyte.
2. The granulosa cells, lining the wall of the follicle
3. The layer of granulosa cells firmly anchored to the zona pellucida by zona-penetrating cellular processes called the corona radiata.
77
At the time of ovulation, what does the mature follicle do?
It protrudes from the ovarian surface.
78
What does proteolytic activity within the theca externa and tunica albuginea induced by a surge of LH do?
It facilitates the rupture of the now mature preovulatory graafian follicle.
79
What does the released gamete do?
It enters the closely apposed uterine tube or oviduct as it complete meiosis I and produces the first polar body.
The oocyte is now a haploid secondary oocyte.
80
Where is the haploid secondary occyte arrested in
Metaphase of meiosis II.
81
What does the secondary oocyte do?
It complete meiosis II and releases a second polar body only if fertilization occurs.
82
What do cells of the ovarian surface do?
They repair the damage of the ovulatory site following the rupture of the follicle.
83
Following ovulation, what does the residual granulosa cell layer do?
It folds and becomes part of the corpus luteum, a major hormone-secreting gland.
84
What happens to granulosa cells in the luteal phase?
They change into granulosa lutein cells.
85
What are the features of the granulosa lutein cells?
They display typical features of steroid secreting cells (lipid droplets, a well-developed smooth endoplasmic reticulum, and mitochondria with tubular cristae).
86
What do granulosa lutein cells secrete?
Progesterone and estrogen in response to LH and FSH stimulation.
87
What does the theca interna change into during the luteal phase?
The theca lutein cells
88
What do theca lutein cells do?
They produce androstenedione and progesterone in response to LH stimulation.
Theca lutein cells provide the granulosa lutein cells with the andostenedione, which is the converted into estradiol by aromatase within these cells.
89
What does the corpus luteum do?
It continues to enlarge and enters an involution stage 14 days after ovulation unless fertilazation occurs. If fertilization takes place, the corpus luteum continues to enlarge an produces progesterone and estrogen under the stimulatory action of hCg.
90
What is hcG synthesized by?
The trophoblast of the implanted embryo.
91
What does regression of the corpus luteum lead to?
The process is called luteolysis and it leads to the formation of corpus albicans, resulting from stromal connective tissue replacing the mass of degenerating luteal cells of the corpus luteum.
92
What are the two autonomic segments of the uterus?
the body and cervix
93
What are the three layers of the wall of the body of the uterus?
The endometrium, the myometrium, and the adventitia or serosa.
94
What does the myometrium of the uterine wall consist of?
Three poorly defined smooth muscle layers. The central layer is thick with circularly arranged muscle fibers and abundant blood vessels.
The outer and inner layers contain longitudinally or obliquely arranged muscle fibers.
95
What happens to the myometrial smooth muscles during pregnancy?
The muscle enlarges (hypertrophy) and the fibers increase in number (hyperplasia).
96
What does the endometrium consist of?
a simple columnar epithelial lining, associated with simple tubular endometrial glands, and the lamina propria called the endometrial stroma.
97
What are the two layers of the endometrium?
A superficial functional layer, lost during menstruation and a basal layer, retained as the source of regeneration of a new functional layer following menstruation.
98
What are the four consecutive phases of the menstural cycle?
mestrual, proliferative, secretory, and ischemic phases.
99
When is the menstural phase?
Last 4 to 5 days, the initial phase of the cycle
100
What is the proliferative phase?
Lasts about 9 days. The thickness of the endometrium increases as a result of the stimulatory activity of estrogen produced by maturing ovarian follicles.
101
When does the progestational phase occur? What happens?
After day 14, when ovulation occurs the endometrium begins its secretory or porgestational phase. It lasts approximately 13 days.
During this phase the endometrium has a thickness of 5 to 7mm and endometrial glands initiate their secretory activity.
102
What happens to the tubular glands, lining epithelium, and secretion during the progestational phase?
The outline of the tubular glands becomes irregular and coiled, the lining epithelium accumulates glycogen, and secretion rich in glycogen and glycoproteins are present in the glandular lumen.
103
What happens to the blood vessels during the progestational phase?
Blood vessels parallel to the endometrial glands increase in length and the lamina propria contains excessive fluid.
104
What is the secretory phase controlled by?
progesterone and estrogen produced in the corpus luteum.
105
What does the regression of the corpus luteum lead to?
an endometrial ischemic phase for about 1 day. A reduction in the normal blood supply, causes intermittent ischemia and subsequent hypoxia, induces the necrosis of the functional layer of the endometrium, which sloughs off during the menstural phase.
106
what is the cervix?
the lower extension of the uterus
107
what does the cervix communicate with?
it communicates with the uterine cavity and the vagina through the endocervix.
108
What is the endocervix lined by?
a floded mucosa consisting of deep crypts arranged in different orientations mimicking a system of mucus-secreting tubular glands.
109
What does the glandular like arrangement of the endocervix do?
it increases the surface area of the mucus producing cells consisting of simple columnar cells whose height varies with the time of the mestrual cycle and their secretory activity.
110
What is the secretory activity of the endocervical epithelial regulated by?
Estrogens and is maximal at the time of ovulation
111
What does the secreted mucus of the endocervix do?
It lubricates the vagina, acts as a antibacterial protective barrier and creates favorable conditions for sperm migration.
112
What is the ectocervix? What is it lined by
The external segment of the cervix lined by stratified squamous epithelium.
113
What is the transformation zone?
An abrupt epithelial transition between the endocervix and the ectocervix.
114
What may occur at the transformation zone?
Dysplasia, an abnormal but reversible condition
115
What is dysplasia?
Disorganized epithelial cells that slough off before reaching full stratified maturity. It can progress into carcinoma in situ, a condition in which proliferation of epithelial cells is very active but within the limits of the basal lamina (cervical intraepithelial neoplasia or CIN).
116
What can dysplasia and carcinoma be detected by?
Routine pap smear.
117
What are the three layers of the vagina fibromuscular tube?
1. an inner mucosal layer (stratified squamous epithelium with a lamina propria usually infiltrated by neutrophils and lymphocytes)
2. A middle muscularis layer (circular and longitudinal smooth muscle)
3. An outer adventitial layer (dense connective tissue)
118
What is the oviduct?
It is the site of fertilization and early cleavage of the zygote (fertilized ovum).
119
What are the four region of the oviduct tube?
1. the proximal fibriated infundibulum
2. a long and thin-walled ampulla
3. a short and thick-walled isthmus
4. an intramural portion opening into the lumen of the uterine cavity
120
What is the fimbriae?
Numerous finger-like projections of the mucosal tissue in the infundibulum
121
What are the ampulla and isthmus lined by?
Mucosal fold projecting into the lumen of the tube.
122
What are the three layers of the oviduct?
1. A mucosal layer supported by a lamina propria, consisting of loose connective tissue
2. a smooth muscular layer, the muscularis
3. a serosal layer
123
What does the mucosa lining of simple columnar epithelium in the oviduct contain?
Two cell populations under hormonal control
1. ciliated cells, which enlarge and produce cilia as folliculogenesis and estrogen production is in progress. Estrogens increase the rate of the ciliary beat. During luteolysis, ciliated cells lose their cilia
2. Nonciliated secretory cells (called peg cells), whose secretory activity is also stimulated by estrogens.
124
What does the peristaltic contraction of the muscular wall, as well as the ciliary activity of the lining epithelial cells do?
They propel the ooctye or fertilized egg/embryo toward the uterus.
