EOS Flashcards
What are the main functions of epithelium?
Protection - selective barrier Absorption Excretion/Secretion Containment Receptors for special senses
What is the function of simple squamous epithelium?
Weak barrier - allows some exchange.
What is the function of endothelium and mesothelium?
Endothelium - exchange and barrier.
Mesothelium - exchange and lubrication.
What are hepatocytes?
Simple cuboidal epithelium.
Secrete bile.
What are enterocytes?
Simple columnar epithelium within SI, caecum, colon.
Absorption and secretion.
What are the two modes of secretion of sweat glands?
Merocrine - exocytosis of vesicles, only in hairless skin, secretes water and electrolytes.
Apocrine - exocytosis of part of cell with lipid droplet, secrete serous fluid (mostly water).
Simple cuboidal/columnar secretory portion, stratified cuboidal ducts.
What is the mode of secretion of sebaceous glands?
Holocrine - programmed cell death and lysis.
Same epithelium as sweat glands.
What kind of glands are sweat glands?
Simple coiled tubular.
What kind of glands are sebaceous glands?
Branched acinar.
Cuboidal cells for secretory portion, stratified squamous duct.
Where will you find myoepithelial cells? What do they do?
Around alveoli/acinus and ducts - facilitate secretion by contracting.
Sweat glands.
What are the functions of integument?
Barrier Regulate temperature and hydration Mechanical support Immunity Neurosensory reception Endocrine Metabolism
What is the epidermis?
Skin consisting of stratified squamous epithelium (layers).
Keratinised - keratinocytes.
What is a primary hair follicle?
Deep in dermis, larger.
Arrector pilli muscle
Sebaceous and sweat glands empty into follicle.
What is a secondary hair follicle?
Small, root near surface.
No glands or muscle.
What are the 4 main tissue types?
Connective
Muscle
Nervous
Epithelium
Connective tissue is a matrix of….
Fibres
Ground substance
Cells - fibrocytes/blasts, adipocytes, mast cells, macrophages, immune cells.
What is the function of collagenous fibres?
Provide stiffness and rigidity
What is the function of irregular connective tissue?
Decreased stretching, maintains shape.
Describe the matrix of hyaline cartilage.
Thin peri cellular matrix, adjacent territorial matrix (fine collagen II - directly surrounds lacunae, dark), interterritorial matrix (coarse collagen II).
What is the function of hyaline cartilage?
Cushioning
Foetal skeleton, growth plates, articular cartilage, airways.
What is the function of bone?
Support Protection of vital organs Facilitates locomotion Stores Ca Harbours Haematopoietic tissue
What do osteoblasts do?
Secrete bone matrix
What do osteocytes do?
Maintain bone matrix
Describe the process of endochondral ossification.
Bone develops from cartilaginous model.
1) chondrocytes proliferate in columns
2) cartilage matrix mineralises
3) chondrocytes die - apoptosis
4) blood vessels invade. Also osteoprogenitor cells.
5) osteoblasts deposit bone on cartilage matrix - primary trabeculae.
6) osteoclasts and blasts remodel primary trabeculae to secondary.
What are the different cells present within blood?
Erythrocytes
Leukocytes - granulocytes (neutrophils, basophils, eosinophils), monocytes, lymphocytes.
Plasma cells
What is the function of neutrophils?
Phagocytose foreign matter, kill bacteria.
What is the function of eosinophils?
Kill metazoan parasites, modulate hypersensitivity reactions.
What is the function of basophils?
Anti-coagulant
Vasodilatory and chemotactic.
What is the function of monocytes?
Macrophages en route to tissues.
Phagocytosis.
What is the function of lymphocytes?
Adaptive immunity (effect and regulate).
What is the function of platelets?
Facilitate haemostasis - contain clotting factors.
What are the functions of lymph nodes?
Filter antigens from lymph.
Produce lymphocytes.
What is the function of trabeculae?
Structural support
What is the function of stroma?
Support parenchyma
What is the function of primary and secondary lymphatic nodules?
B cell area
What is the function of diffuse lymphatic tissue?
T cell area
What does a lymph node cortex contain?
Lymphatic nodules
Diffuse lymphatic tissue
What can be found in lymph node medulla?
Lymphocytes Plasma cells Macrophages All within reticular fibres. Cords between sinuses (lined by endothelium like reticular cells).
Describe the flow of lymph through a lymph node.
Afferent lymphatics (capsule) - subcapsular - trabecular - medullary sinuses - efferent lymphatics (hilus) Opposite flow in pigs.
What are the functions of lymphatic nodules?
Primary - no germinal centre - contain naive B cells.
Secondary - germinal centre (follicular dendritic cells, lymphoblasts, macrophages) - mature B cells
What is the function of the spleen?
Filters, removes and breaks down old erythrocytes Secondary lymphatic organ Produces T and B lymphocytes Stores erythrocytes, platelets and iron Removes blood parasites
Why would the spleen have smooth muscle within its capsule?
Splenic contraction during exercise
What is the parenchyma of the spleen?
White pulp - produces immune cells
Red pulp - surrounds white pulp
What are the components of splenic white pulp?
Peri arteriolar lymphatic sheaths - arteries surrounded by T and B lymphocytes.
Lymphatic nodules
Marginal zone - between red and white pulp, macrophages and B cells.
What are the components of red pulp?
Cords - erythrocytes, macrophages, lymphocytes, plasma cells within reticular connective tissue. Sheathed capillaries (macrophages surrounding dead end capillaries).
Sinuses - discontinuous endothelium and basal lamina supported by reticular fibres.
What is the order of flow of blood through the spleen?
Splenic artery - trabecular arteries - artery of white pulp (PALS) - nodular artery - pulp arteriole (red pulp) - sheathed capillary - splenic sinus - trabecular vein
What is the functional unit of the nervous system?
Neuron
What is the function of dendrites?
Carry nerve impulses to cell body