Histology π¬ Flashcards
1
Q
what is the male productive system formed of?
A
formed of 2 main parts:
- Primary sex organs: Two testes
- Accessory sex organs: Male genital ducts, Accessory genital glands & penis
2
Q
what type of gland is the testis?
A
compound tubular mixed exocrine and endocrine gland
3
Q
what is the testis composed of?
A
composed of supporting stroma and parenchyma.
4
Q
Stroma of the testis
A
1. Tunica vaginalis: (A fold of peritoneum)
- A serous sac formed of an outer parietal &
inner visceral layer separated by a space.
2. Tunica albugenia:
- A capsule of dense fibrous C.T. Thickened posteriorly to form mediastinum testis.
3. Septa (trabeculae):
- Incomplete septa dividing the testis into
about 250 testicular lobules.
4. Reticular fibres
5
Q
parenchyma of the testis
A
1. Exocrine parenchyma: (Sperms)
- Seminiferous tubules & duct system.
2. Endocrine parenchyma: (Sex hormones)
- Leydig cells & fenestrated blood capillaries.
6
Q
what is the definition of seminiferous tubules?
A
The exocrine portion of the testis that produces spermatozoa
7
Q
what is the number of seminiferous tubules?
A
1-4 seminiferous tubules in each lobule.
8
Q
what is the structure of seminiferous tubules?
A
- Separated by connective tissue called the interstitial tissue containing: nerves, lymphatics, interstitial cells (Leydig cells) and fenestrated blood capillaries.
- Highly tortuous compound tubular gland.
- Has a clear basement membrane surrounded by fibrous C.T. with smooth muscle-like cells (myoid cells).
9
Q
what are the types of cells in seminiferous tubules?
A
Lined by 2 types of cells:
1- Spermatogenic cells
2- Sertoli cells
10
Q
what are Spermatogenic cells arranged in?
A
- Spermatogenic cells are arranged in 4-8 concentric layers lying on the basement membrane and are given different names in the different stages of their development.
1. Spermatogonia
2. Primary spermatocytes
3. Secondary spermatocytes
4. Spermatids
5. Spermatozoa
11
Q
when do spermatogonia start maturing into primary spermatocytes?
A
- After puberty, spermatogonia start maturing into primary spermatocytes, secondary spermatocytes, spermatids and spermatozoa in a process known as spermatogenesis.
12
Q
Spermatogenesis
A
- Spermatogenesis is divided into 3 phases: mitosis, meiosis and spermiogenesis:
ββββ-
1- Mitosis is the differentiation of spermatogonia into primary spermatocytes. Spermatogonia (dark type A, pale type A and type B) (mitosis) β Primary spermatocytes.
__________________
2- Meiosis is the first and second meiotic divisions to transform primary spermatocytes to secondary spermatocytes and spermatids respectively.
Primary spermatocytes (1st meiosis) β Secondary spermatocytes (2nd meiosis) β Spermatids.
________________
3- Spermiogenesis is the conversion of spermatids into mature spermatozoa. Spermatids (spermiogensis) β Mature sperms.
13
Q
what is the origin of spermatogonia?
A
From primordial germ cells.
14
Q
site of spermatogonia
A
1-2 layers on the basement membrane.
15
Q
shape of spermatogonia
A
Rounded
16
Q
what are the changes that happen to spermatogonia?
A
17
Q
Origin, site, shape & changes in Primary, Secondary spermatocytes and spermatids
A
18
Q
what is Spermiogenesis?
A
It is the morphological changes which occur in the spermatid to be changed into mature sperm (without cell division).
19
Q
what are changes that happen in Spermiogenesis?
A
20
Q
what is the length of mature spermatozoon?
A
Long (65 ΞΌm long)
21
Q
structure of Mature spermatozoon
A
The mature spermatozoon consists of:
1. Head
2. Neck
3. Tail:
a. Middle piece b. Principal piece c. End piece
22
Q
Length, Shape & Structure of parts of spermatozoon
A
23
Q
Site of Sertoli Cells
A
between spermatogenic cells extending from the basement membrane to the lumen.
24
Q
L/M of Sertoli Cells
A
Shape: Tall columnar cells with irregular lateral surfaces. βwith invaginations that hold spermatogoniaβ
Nucleus: Basal oval nucleus.
Cytoplasm: Pale cytoplasm.
25
E/M of Sertoli Cells
- Sertoli cells are joined to each other by tight junctions forming the blood- testis barrier.
- The cytoplasm contains numerous lysosomes, sER, mitochondria and Golgi apparatus.
26
what are the functions of Sertoli Cells?
- Providing spermatogenic cells with nutritive factors. "selective"
- Preventing auto-immune reactions by isolating spermatocytes and sperms from the host immune system through the blood-testis barrier.
- Secretion of androgen-binding protein (ABP) which concentrates intra-testicular testosterone in sufficient levels to support spermatogenesis.
- Phagocytosis of degenerated cells and excess cytoplasm "residual bodies" shed off during spermiogenesis.
27
what is **Blood-testis barrier**?
Continuous tight junctions between lateral borders of Sertoli cells.
28
what does the **Blood-testis barrier** divide the seminiferous tubule into?
https://youtu.be/71h_9Juq57Y
Divides the seminiferous tubule into 2 compartments:
**Outer (basal) compartment:**
- Only spermatogonia
**Inner (adluminal) compartment:**
- Primary spermatocytes.
- Secondary spermatocytes.
- Spermatids.
- Mature spermatozoa.
29
How do formed spermatogenic cells pass the BTB to the lumen?
- Newly formed primary spermatocytes temporarily disassemble the blood-testis barrier and move to the inner adluminal compartment. During this process, junctions disassemble above the translocating cells and at the same time, new junctions assemble below.
| **(Like an elevator)**
30
Definition of Leydig Cells
The endocrine portion of the testis that produces testosterone
31
Site of Leydig Cells
In the interstitial tissue lying between the seminiferous tubules.
32
L/M of Leydig Cells
**Shape:** Large polygonal cell.
**Nucleus:** Central rounded nucleus.
**Cytoplasm:** Acidophilic Vacuolated. (Lipid content)
33
E/M of Leydig Cells
The cytoplasm is rich in:
1. Numerous lipid droplets.
2. Mitochondria with tubular cristae. (like cells in ZF of adrenals)
3. Numerous sER.
34
Function of Leydig Cells
Synthesis of testosterone hormone
35
what are ducts related to male genital system?
**Intra-testicular:**
- Tubuli recti
- Rete testis
**Extra-testicular:**
- Vasa efferentia
- Epidydimus
- Vas deferens
- Ejaculatory duct
- Urethra
36
Site of Tubuli Recti
Small straight tubules at the end of Seminiferous tubules
37
Lining epithelium of Tubuli Recti
- In the proximal portion: Sertoli cells
- In the distal portion: Simple cubical
38
Site of Rete testis
Narrow branching tubules in Mediastinum testis
39
Lining epithelium of Rete testis
simple cubical
40
Site of Vasa Efferentia (Efferent Ductules)
Extending from rete testis pierce tunica albuginea to head of epididymis
41
Structure of Vasa Efferentia (Efferent Ductules)
- Epithelial Lining: Alternating Simple cuboidal non ciliated & simple columnar ciliated epith.
42
Function of Vasa Efferentia (Efferent Ductules)
Transport sperm from rete testis to epididymis
43
Site of Epididymis
On the posterior surface of the testis
44
Structure of Epididymis
- Long highly coiled duct formed of head, Body & Tail
1) Epithelium: Pseudostratified columnar with Stereocilia (Long microvilli, not true cilia)
2) Vascular CT & Smooth muscle fibers
45
Function of Epididymis
- Biochemical maturation & short-term storage of sperms
- Phagocytosis of residual bodies
- Transport sperm from Vasa efferentia to Vas deferens
46
Site of Vas Deferens (Ductus Deferens)
- Begins from epididymis in scrotum
- Ascends within spermatic cord & passes through Inguinal canal
- Reaches posterior aspect of Urinary bladder
- Expands to form the Ampulla
- Joins duct of seminal vesicle forming the Ejaculatory duct
47
Structure of Vas Deferens (Ductus Deferens)
48
Function of Vas Deferens (Ductus Deferens)
Transports sperm by rapid powerful peristaltic contraction from epididymis to the ejaculatory ducts
49
Site of Ejaculatory ducts
- Formed by union of vas deferens and duct of seminal vesicle
- It penetrates the prostate and opens in the prostatic urethra
50
Lining epithelium of Ejaculatory ducts
Pseudostratified columnar or Simple columnar epithelium
51
Function of Ejaculatory ducts
Transport sperm from vas deferens to urethra
52
Compare between prostatic, membranous & penile urethras according to length, site, epithelium & function
53
Summary of male genital ducts
54
what is the type of Seminal Vesicles?
These are paired highly tortuous tubular glands
55
Site of Seminal Vesicles
Posterior to urinary bladder
56
length and size of Seminal Vesicles
Each about 15 cm long
57
Structure of Seminal Vesicles
58
Function of Seminal Vesicles
- Exocrine glands that secrete Viscid Yellowish alkaline fluid that makes up 70% of the ejaculate.
- This fluid contains:
1) Fructose: Major energy source of sperm.
2) Fibrinogen: Slight Coagulation of semen after ejaculation
59
Site of Prostate
Surrounds the Neck of bladder and Prostatic urethra
60
Lining of Prostate
Cubical, Columnar or Pseudostratified columnar epithelium, Depending on the activity of gland
61
Histological structure of Prostate
1. Supporting stroma
2. Parenchyma
62
Stroma of Prostate
**Capsule:** Thick capsule rich in smooth muscle fibers
**Trabeculae:** Thick C.T septa rich in smooth muscle fibers
- The smooth muscle fibers condense around the urethra to form the internal urethral sphincter
- Reticular fibers
63
Parenchyma of prostate
64
what is Corpora Amylacea?
Small concretions in the lumen of most of the glands - Dried & calcified prostatic secretions
65
what happens to Corpora Amylacea with time?
Become more numerous & much calcified in old age
66
what is the function of the prostate?
- Secretes milky fluid that makes 25-30% of the semen & rich in Proteolytic enzymes to liquefy the seminal clot and release the motile sperms
67
Site of Bulbourethral (Cowper's) glands
- Paired small glands
- Present in Urogenital diaphragm under membranous urethra
68
Structure of Bulbourethral (Cowper's) glands
**Stroma**
- Capsule: Thin
- Trabeculae: Thin C.T septa dividing gland into irregular lobules
- Reticular fibers
**Parenchyma**
- Acini lined by Simple cubical, columnar or squamous epith.
69
Function of Bulbourethral (Cowper's) glands
Secrete mucus fluid that empties directly into penile urethra and helps to lubricate the urethra
70
what are the parts of the penis?
Root, Body & glans penis
71
what is Root of penis?
The most proximal, fixed part of the penis
72
Body of the penis
**3 Cylindrical masses of erectile tissue:**
- 2 dorsal corpora cavernosa
- 1 ventral corpus spongiosum
**These 3 masses:** Composed of numerous vascular spaces lined by endothelium
73
Glans penis
The distal end of penis covered with a fold of skin called Prepuce
74
Compare between Seminal vesicle, Prostate & Bulburethral glands
75
what covers the ovary?
- Outer mesothelium
- Tunica albuginea
76
Lining epithelium of the outer mesothelium of the ovary
77
what is tunica albugenia of the ovary formed of?
Tunica = Layer, Albuginea = White
- formed of white collagenous fibers
78
Structure of the ovary
79
ovarian follicles before and after puberty
80
what are the Structural components for each follicle?
**Oocyte:**
* Female germ cell
* May be primary or secondary
**Follicular cells**
**Supporting stroma**
81
what are the characteristcs of Primordial follicles?
- The only follicles present till the age of puberty
- At birth: Ovary contains about 400,000 primordial follicles
- At puberty: Only 40,000 remain and the rest undergo atresia (Degenerate)
82
Structure of Primordial follicles
**Primary oocyte**
- Not more than 30 um
- 46 d-chromosome
- Arrested in Prophase of the first meiotic division from intrauterine life till the age of puberty
**Follicular cells**
- Single layer of flat squamous cells
**Stroma**
- No definite stroma
83
when do primary follicles start maturing?
Starts maturation at puberty
84
How many primordial Follicles are activated by FSH?
- In each ovarian cycle: 12-15 primordial follicles are activated by F.S.H
85
How many Primary Follicles reach maturity in every cycle?
- Only 1 or 2 reach maturity (Becomes the dominant follicle) & released at ovulation
- The rest degenerate (Atretic follicles)
86
what are the types of Primary Follicles?
Depending on the number of layers of follicular cells, they are:
1. Unilaminar primary follicles
2. Multilaminar primary follicles
87
Compare between unilaminar & multilaminar primary follicles
88
what is zona pellucida?
Thick membrane formed of Glycoproteins
89
what is zona pellucida produced by?
Produced by: Both the oocyte & follicular cells:
- Oocyte: Send microvilli into it
- Follicular cells: Send processes or Pseudopodia to provide nutrition to the oocyte through gap junction
90
Structure of secondary follicle
91
what is another name for Mature Graafian follicle?
Pre-ovulatory follicles
92
Size of Mature Graafian follicle
Large about 2 cm, Forms a bulge at the ovary surface visible with ultrasound
93
Structure of Mature Graafian follicle
94
what is the definition of ovulation? and what is released in it?
- A hormone-stimulated process by which the 2ry oocyte, Zona pellucida & Corona radiata are expelled in the peritoneal cavity near entrance or the rallodian tube
95
Time of ovulation
In about the middle of menstrual cycle
96
How does ovulation take place?
- In the days preceding ovulation, Mature Graafian follicle secretes higher level of Estrogen which Stimulates release of GnRH from Hypothalamus which leads to Rapid release of L.H from the pituitary gland
97
what are the effects of LH (regarding ovulation)?
98
what is the definition of corpus luteum?
Large temporary endocrine gland
99
How is Corpus luteum formed (Events)?
- Ovulation is followed by collapse of the wall and blood from disrupted capitartes forms a plood clot in the antrum
- Granulosa cells form Granulosa lutein cells
- Theca interna cells form Theca lutein cells
100
Compare between granulosa lutein and theca lutein cells
101
what is the fate of corpus luteum?
102
what is the histologcal structure of fallopian tube (oviduct)?
- Mucosa
- Muscolaris
- serosa
103
Mucosa of fallopian tube
104
Musculosa of fallopian tube
Interwoven circular and longitudinal muscles
105
Serosa of fallopian tube
Thin serosa
106
what Are the layers of the body of the uterus?
1) Endometrium (Mucosa)
2) Myometrium (Muscle layer)
3) Perimetrium (Outer C.T layer)
107
what is endometrium composed of?
- epithelium
- Lamina propria (Stroma)
- Uterine glands (Endometrial glands)
108
epithelium of the endometrium
Simple columnar with ciliated & secretory cells
(Lining the uterine glands)
109
lamina propria of the endometrium
Contains:
- Type Ill collagen
- Fibroblasts
- Ground substance
110
what is a type of uterine glands (endometrial Glands)?
Simple tubular glands
111
what are endometrial Glands lined by?
Lined by secretory cells
112
what do cells of endometrial glands secrete?
Cells secrete glycogen
113
divisions of endometrium
114
what characterizes the myometrium?
The thickest layer of the uterus
115
what is the structure of myometrium?
116
what happens to smooth muscle cells of myometrium during pregnancy?
1. Hyperplasia & Hypertrophy of Smooth muscle cells
2. Increased Collagen production by the smooth muscles
117
Histologica structure of perimetrium
1) Outer C.T layer
2) Adventitia in some areas
3) Largely serosa (Covered by peritoneum)
118
what is the histological structure of uterine cervix?
- Endocervical mucosa
- Exocervical Mucosa
- Deep layer of the cervix
119
Endocervical Mucosa
1) Simple columnar epithelium
2) Thick lamina propria: with cervical glands (Mucus secreting)
3) Does not change its thickness
4) Not shed during menstruation
120
exocervical mucosa
1) Around the External Os
2) Nonkeratinized stratified squamous epith continuous with the vagina
3) The junction between the 2 types of epithelium is abrupt (At the External Os)
121
deep layer of the cervix
Dense connective tissue with much less smooth muscles that rest of the uterus
122
The endometrial changes during menstrual cycle
123
what is the definition of the placenta?
Disc shaped structure
124
what is the placenta formed of?
125
development of chorionic villi
126
what is the structure of placental chorionic villi?
- Mesenchymal Core
- Trophoblast cells: 2 types of cells
127
mesenchymal Core of chronic villi
Containing capillaries served by a branch of the umbilical artery & vein
128
what is the site of trophoblastic cells of chronic villi?
Between the villous capillaries of the mesenchymal core and the lacunae of maternal blood in the decidua basalis
129
compare between Cytotrophoblast & Syncytiotrophoblast
130
what is the definition of the placental barrier?
The diffusion barrier between maternal and fetal circulations
131
what are the components of the placental barrier?
Components 5 layers:
1) Trophoblast
2) Basement membrane of trophoblast
3) Mesenchymal tissue
4) Basement membrane of capillary endothelium
5) Endothelium
132
what are the functions of the placenta?
- Exchange of gases, nutrients and wastes between fetal blood in the capillaries of the villi & maternal blood
- Endocrine function:
1) HCG
2) Placental Lactogen (Somatomammotropin)
3) Relaxin
4) Other Growth factors
5) Estrogen & Progesterone
133
what is a Histological structure of the vagina?
- mucosa
- Muscular layer
- Adventitia
134
mucosa of the vagina
135
muscular layer of the vagina
- Inner circular
* Thick outer longitudinal layers of smooth muscles
136
adventetia of the vagina
Dense C.T rich in elastic fibers, making the vaginal wall strong & elastic
137
what is the Breast covered by?
Covered by thin skin
138
what is the Breast Composed of?
- Each breast (Mammary gland) is composed of 15-25 lobes
**Each lobe:**
1. Is a separate gland
2. Separated from the other lobes by dense fibrous C.T and much adipose tissue
3. Has its own Lactiferous duct which emerges in the nipple
139
openings of the nipples
has 15-25 openings, each about 0.5 mm
140
What characterizes the areola?
1. The skin covering the nipple
2. Thin skin with more melanin
3. Becomes darker during pregnancy
141
what type of glands is the mammary glands?
Compound branched tubulo-alveolar
142
Stroma of mammary gland during puberty
143
parenchyma of mammary gland during puberty
144
what causes breast development during pregnancy?
1. Estrogen & Progesterone hormones
2. Pituitary Prolactin hormone
3. Placental lactogen hormone
145
Stromer of breast during pregnancy
- Reduced in amount
- Loose C.T in the lobules is infiltrated by Lymphocytes & Plasma cells
146
Parenchyma of breast during pregnancy
- Alveoli develop by Proliferation of the terminal ends of the ducts
- Alveoli lined by:
1. Simple cuboidal cells
2. Myoepithelial cells lie between the cells & basal lamina
- Late in pregnancy, Alveoli & Ducts accumulate Colostrum & become Dilated
147
what happens to breast immediately after parturition?
**Immediately after parturition, alveoli start active milk secretion:**
1. Large amounts of proteins: secreted by Merocrine action
2. Lipid droplets: secreted by Apocrine action
3. Lactose
