Histology Flashcards
color of adrenal cortex and why
yellowish in colour due to high content of lipid
origin of the adrenal cortex
Mesodermal in origin
Zona glomerulosa
- which gland?
- location?
- group cell morphology?
- cells and nucleus morphology?
- secrete?
- adrenal cortex
- under the capsule
- cells arranged into round and oval groups
- The cells are columnar with spherical deeply stained nuclei
- secrete aldosterone which causes sodium retention under
control by angiotensinogen II
The cells that have the highest content of cholesterol in the body.
Zona fasciculata
what secreted by Zona fasciculata?
glucocorticoids which is controlled by ACTH
composed of straight parallel cords of cells in adrenal cortex
Zona fasciculata
The broadest zone in adrenal cortex
Zona fasciculata
Zona fasciculata characteristics
- the broadest zone composed staight parallel cords of cells
- the cells are polyhedral with large vesicular nuclei which can be binucleated
- Their cytoplasm is filled with lipid droplets so appear vacuolated due to dissolved lipid droplets and has a spongy appearance, so called spongiocytes
- The cells have the highest content of cholesterol in the body
- The cells secrete glucocorticoids which is controlled by ACTH.
from adrenal cortex that secrete sex hormones
Zona reticularis
has less lipid droplets and more lipofuscin pigments
Zona reticularis
origin of adrenal medulla
ectodermal in origin
has Chromaffin cells
adrenal medulla
secrete adrenaline Chromaffin cells
Chromaffin cells
Morphology of Chromaffin cells
The cells are oval or polygonal with eccentric nuclei with basophilic cytoplasm
stain of medullary cells makes it brown
Chromaffin reaction
stain of medullary cells makes it red
Iodine stain
stain of medullary cells makes it green
Vulpian test
what to add in Vulpian test on medullary cells
ferric chloride
what to add in Chromaffin reaction test on medullary cells
potassium dichromate
origin of thyroid gland
endoderm
Parenchyma of thyroid gland consists of
thyroid follicles & inter-follicular cells
lining of the thyroid follicles
low cuboidal epithelium
what in the lumen of the thyroid follicles
colloid, a homogenous gelatinous acidophilic material stained intensely with PAS
synthesize thyroid hormones
follicular cells (thyrocytes)
cells secrete calcitonin?
parafollicular cells ( C cells)
cells secrete parathormone?
Chief cells of parathyroid glands
cells of pancreas
A cells
B cells
D cells
secretion and location of A cells of pancreas
secrete primarily glucagon and are usually located
peripherally
secretion and location of B cells of pancreas
produce insulin, are the most numerous, and are
located centrally
secretion and location of D cells of pancreas
secretion and location of B cells of pancreas
origin of Pineal gland
Neuro-ectodermal in origin
function of pinealocytes
secrete melatonin during night and serotonin during day
what the pineal gland contain?
- pinealocytes
- Glial cells
- Corpora arenacea (brain sand)
Corpora arenacea
it is brain sand in pineal gland, which is a calcified concretion containing hydroxyl apatite
staining of acidophilic cells of anterior pituitary
eosin
staining of basophilic cells of anterior pituitary
PAS (Periodic acid–Schiff stain)
secrete GH
Somatotropic cells
secrete prolactin
Mammotrophs
secrete
TSH
ACTH
LH, FSH
Thyrotrophes
Corticotrophes
Gonadotrophes
secrete oxytocin, ADH
Pars nervosa
stain of non capsulated lymphatic nodules
basophilic
what the parenchyma of the lymphatic follicle contain?
B lymphocytes, few T lymphocytes and macrophages
cells called spongiocytes
cells of zona fasiculata
stain of medulla to differentiate from cortex
Chromaffin reaction (potassium dichrome): brown
iodine: red
Vulpian test (ferric choloride): green
most of the cells of the par tuberalis are
gonadotrophes
Structure of lymphatic follicles
A- Stroma which consists of reticular cells and fibers.
B- Parenchyma which consists mainly of B lymphocytes and few T lymphocytes and macrophages
Presence of germinal center of primary and secondary follicles
a- Primary follicle: without germinal center.
b- Secondary follicle: with germinal center.
What is germinal center
is a pale central area which is formed as a result of exposure to infection or antigens, so the small B
lymphocytes (have dark nuclei) develop into medium sized B lymphocytes (have pale nuclei) which aggregate in the center of the follicle forming a pale area which is called germinal center.
Characteristics of capsule of lymph nodes
- Dense fibrous C.T and is penetrated by afferent lymphatics.
- It is thickened at the hilum of the node.
Characteristics of trabeculae of lymph nodes
- Arise from the deep surface of the capsule.
*They are regular in the cortex and divide it into cortical compartments. - In the medulla, they branch and anastomose dividing it into irregular areas.
Characteristics of capsule of lymph nodes
Reticular fibrous network
Characteristics of cortex of lymph nodes
- Formed of lymphatic follicles which are found in the cortical
compartments. - The follicles are either primary or secondary
Characteristics of capsule of spleen
- Thick fibrous C.T.
- Not penetrated by afferent lymphatics.
- Is covered by peritoneum
Characteristics of trabeculae of spleen
- They arise from the hilum of the spleen.
- Divide the spleen into incomplete intercommunicating spleniclobules
Characteristics of parenchyma of spleen
II- Parenchyma:
* Formed of splenic lobules, each splenic lobule is formed of:
A- White pulp: (Malpighian corpuscle):
* Formed of lymphatic follicles and may contain germinal center.
B- Red pulp:
* Occupy the areas between the white pulp.
* Formed of splenic cords separated by blood sinusoids.
Location of thymus dependent zone
found in the deeper part of the cortex of lymph nodes
Content of thymus dependent zone
contains T lymphocytes that are developed in the thymus gland and migrate to the thymus dependent zone by the blood
What are the lymph sinuses
Subcapsular sinus
Cortical and subcortical sinus
Medullary sinuses
Lining of the pharyngeal tonsils
Pseudo-stratified columnar ciliated epithelium
Location of the pharyngeal tonsils
nasopharynx
Lining of the palatine tonsils
Stratified squamous non-keratinized epithelium
Lining of the crypts of the palatine tonsils
Stratified squamous non-keratinized epithelium
Tonsils that have crypts
Palatine
The C.T capsule of palatine tonsils separates
The tonsils from the muscular wall of the pharynx
Responsible for forming antibodies quickly against infective agents which may be taken with food or air
Lingual tonsils
What are the adenoids
The pharyngeal tonsil
Structure of the thymus barrier
1- Continuous capillary endothelium.
2- Complete basement membrane (around the endothelium).
3- Perivascular space around the capillary that contains macrophages
which phagocytose the antigens that escape outside the capillary.
4- Complete layer of reticular epithelial cells.
Function of the thymus barrier
separate the developing immature Tlymphocytes in the thymus gland from the antigens in the
circulating blood
Medulla of the thymus content
1- T- lymphocytes:
* They are less in number than in the cortex.
* The have completed their development in the cortex and become
pushed into the medulla.
2- Reticular epithelial cells.
3- Macrophages.4- Hassal’s corpuscles:
* It is a central hyaline acidophilic mass surrounded by concentric
layers of reticular epithelial cells.
* The acidophilic mass is degenerated cells.
Cortex of the thymus contents
A- The cortex:
* It is the outer dark part of the lobule (due to its high content of
lymphocytes), it contains the following cells:
1- Lymphoblasts:
* Present in the outer part of the cortex.
* They have dark nuclei and derived from CFUs in the bone marrow.2- T-lymphocytes:
* Present in the deeper part of the cortex.
* Numerous and derived from the lymphoblasts.
3- Reticular epithelial cells:
* They are branched with a pale nucleus.
* They are secretory cells (responsible for secretion of thymic
hormones).
4- Macrophages.
responsible for secretion of thymic hormones
Reticular epithelial cells
Characteristics of hassal’s corpuscle
It is a central hyaline acidophilic mass surrounded by concentric layers of reticular epithelial cells.
derived from CFUs in the bone marrow
Lymphoblasts in the thymus
Cells Numerous and derived from the lymphoblasts
T lymphocytes
Cells in the thymus branched with pale nucleus
Reticular epithelial cells
