Histology practical definition Flashcards
What type of epithelium lines the trachea?
Pseudostratified ciliated columnar epithelium
Also known as respiratory epithelium.
What distinctive cartilage feature is found in the trachea?
C-shaped hyaline cartilage rings
What are the two major types of glands found in the trachea?
- Serous glands
- Mucous glands
How does the histology of the trachea differ from that of the primary bronchi?
The respiratory epithelium is shorter in the bronchi and they have fewer goblet cells.
What are the key histological features of bronchioles?
- Lack glands
- Lack cartilage
- Lack lymphoid aggregates
- Transition from ciliated columnar to cuboidal epithelium
- Thin lamina propria with elastic fibers
What is the primary function of the spleen?
Blood filtration and immune response
What are the two main components of the spleen?
- White pulp
- Red pulp
What type of cells are primarily found in the white pulp of the spleen?
Lymphocytes
What is the function of the thymus?
Maturation and instruction of T lymphocytes
What are the two main regions of the thymus?
- Cortex
- Medulla
What occurs in the cortex of the thymus?
Positive selection of T cells
What is the role of Hassall’s corpuscles in the thymus?
They are involved in the maturation process of T cells.
What is the blood-thymus barrier?
A physical barrier preventing antigens from entering the thymus
What do lymph nodes primarily filter?
Lymph
What are the two main regions of a lymph node?
- Cortex
- Medulla
What type of cells are found in the medulla of a lymph node?
- Macrophages
- Lymphocytes
What type of epithelium lines the oesophagus?
Non-keratinised stratified epithelium
What are the four regions of the stomach?
- Cardia
- Fundus
- Body (corpus)
- Pylorus (pyloric antrum)
What type of cells secrete hydrochloric acid in the stomach?
Parietal or oxyntic cells
What are the three parts of the small intestine?
- Duodenum
- Jejunum
- Ileum
What type of glands are present in the duodenum?
Brunner’s glands
What is a key feature of the large intestine?
Absence of plicae circulares and villi
What types of glands are found in the salivary glands?
- Serous glands
- Mucous glands
What are the three major salivary glands?
- Parotid
- Submandibular
- Sublingual
What distinguishes serous secretions from mucous secretions?
- Serous: watery fluids
- Mucous: viscous fluids
What are the two components of the pancreas?
- Exocrine pancreas
- Endocrine pancreas
What is the functional unit of the exocrine pancreas?
Serous acinus
What hormones are produced by the islets of Langerhans?
- Insulin
- Glucagon
- Somatostatin
- Pancreatic polypeptide
What type of cells make up the exocrine pancreas?
Serous secretory cells
These cells secrete proteins and digestive enzymes.
What are the main components of the endocrine pancreas?
Islets of Langerhans
The islets are embedded in the exocrine pancreas.
How can islets of Langerhans be identified histologically?
Cells within the islet stain more faintly than acini or show different morphology and arrangement.
What hormones does the thyroid gland produce?
- Thyroxine (T4)
- Triiodothyronine (T3)
- Calcitonin
What is the shape and location of the thyroid gland?
Butterfly-shaped, located in the anterior portion of the neck
What is the primary function of thyroxine and triiodothyronine?
Stimulate metabolic rate
What role does calcitonin play in the body?
Regulates calcium metabolism by inhibiting osteoclast function and promoting calcium deposition in bones
What is the structure of the thyroid gland?
Organized in two lobes linked by an isthmus, composed of cuboidal epithelium surrounding colloid-filled follicles
What regulates the activity of follicular cells in the thyroid?
TSH (Thyroid Stimulating Hormone)
What is the primary structural unit of the liver?
Classic lobule
What is the shape of the classic lobule in the liver?
Irregular polygonal prism shape
What is found at the center of the liver lobule?
Centrilobular vein (central vein)
What structures are found at the corners of the liver lobule?
Portal spaces or portal triads containing hepatic arterioles, portal venules, bile ducts, and lymphatic vessels
What is the main function of the kidneys?
Regulate fluid balance and produce renin, erythropoietin, and vitamin D
What are the main structural components of the kidney?
- Outer cortex
- Inner medulla
What is the functional unit of the kidney?
Nephron
What does the renal corpuscle consist of?
Glomerulus and Bowman’s capsule
What is the role of the glomerulus in the kidney?
Composed of capillaries with fenestrated endothelium for filtration
What type of epithelium lines the proximal and distal convoluted tubules?
Simple cuboidal epithelium with microvilli (brush border)
What is the primary function of the bladder?
Store urine formed in the kidneys
What is the basic histologic structure shared by the calyces, pelvis, ureter, and bladder?
The wall of the ureter thickens as it approaches the bladder
What type of epithelium makes up the bladder’s mucosa?
Transitional epithelium
Fill in the blank: The transitional epithelium of the bladder comprises _______ layers of cells.
3-6
What are the layers of cells in the transitional epithelium?
- Basal layer (cuboidal or columnar)
- Intermediate layer (polygonal)
- Superficial layer (domed-shaped, binucleated cells)
