Histology Flashcards
- Which of the following is the best choice to be classified as a component of the innate immune system?
Natural Killer cells
- Erythrocytes comprise what percentage of all the cells in the body?
25%
Where are erythrocytes produced?
Bone marrow
Are erythrocytes metabolically active or inactive?
Active
How long are RBC in circulation?
100-120 days (human adult)
What are Metarubricytes?
Metarubricytes are erythroid precursors possessing a pyknotic (or apoptotic) nucleus, the last stage of maturation before the erythrocyte losses its nucleus. AKA Normoblast
What is the order of the erythroid series?
Proerythrocyte (rubriblast/proerythroblast)
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Basophilic erythroblast (prorubricytes)
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Polychromatophilic erythroblast (rubricytes)
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Orthochromatophilic erythroblast (Normoblast/metarubryocyte)
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Reticulocyte
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Erythrocyte
What is the order of the Granulocytic series?
Myeloblast | Promyelocyte | Myelocyte | Metamyelocytes | Mature Granulocyte
How do you calculate MCV?
MCV = haematocrit / [rbc]
What are the key effector cells in the adaptive immune system?
CD8 lymphocytes
What are the two steps in phagocytosis?
1- Phagocytosis begins with the neutrophil or macrophage flowing around the pathogen and engulfing it so that it winds up enclosed in a phagosome (phagocytic vesicle). But this is only the first step, because the more challenging task of destroying the microorganisms remains. Indeed, some pathogens have special, effective mechanisms for frustrating this destruction step.
2- The next step is the fusion of lysosomes with the phagosome. The result is called a phagolysosome. Lysosome are derived from the Golgi apparatus, much like secretion vesicles, but their contents are focused on destroying microorganisms.
What are polymorphonuclear cells? (a leukocyte with a multilobed nucleus)
Neutrophils and Natural Killer (NK) Cells
Where are Fc receptors found?
B lymphocytes, follicular dendritic cells, natural killer cells, macrophages, neutrophils, eosinophils, basophils, human platelets, and mast cells – that contribute to the protective functions of the immune system.
Are phagocytes a component of the innate immune system?
Yes. Phagocitic cells are innate. *Neutrophils, Macophages and Natural Killer Cells.
Name 3 phagocytic cells that are part of the innate immune system?
Neutrophils, Macophages and Natural Killer Cells.
What does the release of metarubricytes into circulation indicate?
They can appear in circulation as an indication of strong bone marrow regeneration response
H: what are the three main categories of a cell features?
1-universal (bacteria, archaea eukaryoktes)
2-Eukaryotic (protists, plants, fungi and animals)
3-Metazoan (animals)
H: What are universal characteristics of bacteria, archaea and eukaryotes?
- Cell membrane
- Phospholipid bilayer
- Imbedded (integral) and surface (peripheral) membrane protein
- Transmembrane proteins
- Surface carbohydrates
- Cytoplasm= water based internal fluid of cell
- Nucleus= DNA containing organelle
- Sodium potassium pump. (Na+ lower K+ higher)
- ATP universal energy source
H: What are Eukaryotic characteristics of protists, plants, fungi and animals?
-Endomembrane system = organelle formation
-Mitochondria
-Cytoskeleton :
:Microfillaments (movement and stability of cells internal structures)
:Intermediate fillaments= cell specific provide rigid strength
:Microtubles= Large structures made of tubulin proteins responsible for moving organelles cilia and chromosomes.
H: What are Metazoan characteristics of Animals?
- Cell specialisation
- Intercellular junctions= tight junctions
- Mechanical junctions (Desmosomes, hemidesmosomes and adherent junctions)
- Communication junctions (gap junctions)
H: What are two types of connective tissue
1) Fibrous - fat, cartilage and bone
2) Blood - haematopoietic
H: What are fundamentals of connective tissue?
- Originate from mesoderm
- Capable of regeneration
- Matures and differentiate throughout life
- Cells exist in a matrix combined of fibres and ground substance
H: What are the cells of fibrous tissues?
- Mesenchymal cells
- Fibroblasts
- Fibrocytes
- Reticular Cells
- Apipocytes
- Mast cells
- Macrophages
- Lymphocytes
- Plasma cells
H: What are mesenchymal Cells?
- Large ovoidal cells with ovoid nucleus
- Present in a loose matrix
- Pluripotent stem cells present in embryo
H: What are Fibroblasts?
Fibroblasts form all connective tissue- Secrete fibres and ground substance
Connective tissue can be two types?
1- Dense >50% fibres (Regular parallel fibres and Irregular (no fibre organisation)
2- Loose <50% fibres
What are Fibrocytes?
Maintain fibres and ground substance (less active)
elongated spindle shape
Mesenchymal SC –> Fibroblasts —> fibrocytes
What are Reticular cells?
- Specialised fibrocytes
- stellate cells that stain basophillic with spherical nucleus
- found in haemopoietc and lymphatic organs as well as repairing wounds
- Phagocytotic properties and secrete reticulin fibres
What are Adipocytes?
Unilocular= white adipose (large lipid droplets) Multilocular= Brown adipose (smaller lipid droplets)
What are Mast cells?
Mast cells arise in bone marrow and differentiate in connective tissue.
- prevelent in skin intestines and lung
- Spherical ovoidal shape with central nucleus. -Stain very basophillic
- Contain heparin, histamine, proteases etc, which mediate inflamation and anaphylaxis
What are Macrophages?
Arise from blood monocytes -Phagocytose foreign particles - migratory cells :secrete proteases and GAG-ases -have psudopodia fixed macrophages= histocytes
What are lymphocytes?
T and B lymphocytes
-spherical cells with high nucleas (Cytoplasm ratio)
What are plasma cells?
Originate from B Lymphocytes
-Basophilic cytoplasm (rich is rER) with a perinuclear clear zone
What are four main types of fibres?
1) Collagen
2) Reticular Fibres
3) Elastic Fibres
4) Fibrous adhesion proteins
a) Fibronectin- bind to other fibres and cell membranes (plays a roll in adhesion, differentiation and growth)
b) Laminin = Large glycoprotein (major constituent of basal lamina
Explain Collagen
- Protein that provides strength and flexibility
- Made up of 3 types of proteins bound in a helix (procollagen) -Glycosolated
What are the 4 types of collagen?
Type I - Located in the dermis, capsules, tendons and ligaments
Type II - Located in the hyaline and elastic cartilage and invertebral disks.
Type III- Associated with blood vessles, nerves and stroma of organs
Type IV: Located in the basal lamina of epithelia , muscle cells and neuroganglia
What do collegen molecules form?
Collagen molecules self assemble hilically into collagen fibrils.
What do collagen fibrils form?
Collagen fibrils aggregate to form branching collagen fibres
What are Reticular fibres and how can you see them?
Reticular fibres are type II collagen coated in proteoglycans and glycoproteins.
*You need silver stain to see them.
They are Thin flexible fibres acting as a support network for cells. Synthesised by fibroblasts.
What are Elastic fibres?
Elastic fibres consist of elastin supported by fibrillin. Provides areas like the aorta with the elasticity lacked by collagen. (damaged elastic fibres are replaced with collagen decreasing function)
What is ground substance?
The gell in which cells and fibres are suspended. Composed of glycosaminoglycans (GAGs), proteoglycans, plasma constituents, water and ions.
What are GAGs?
glycosaminoglycans are simple sugar chains with highly polar side chains. The side chains act to attract and hold water
What are proteoglycans?
GAGs bound to a protein core.
Where is loose conective tisssue found?
- Blood Vessles, lymphs and nerves
- Lamina of hollow organs
- Stroma of solid organs
- Composed of collagenous reticular and/or elastic fibres
Where is dense regular tissue found?
Tendons and ligaments
Where is dense irregular tissue found?
Found in dermis of skin, muscle, sclera of eye and organ capsules (can resist forces in all direction)
Where can you find reticular connective tissue ?
Composed of reticular cells and fibres
-Supporting stroma of bone marrow, lymph nodes and spleen.
Marked elevation in MCHC is most likley to be associated with what type of iron deficiency?
Iron deficiency anemia
Is C1 an important mediator that interacts with IgG or IgM bound to antigen?
YES
True or false? Lymph nodes germinal centres mostly contain reactive B cells
True
Explain some important evolutionary steps of innate immune host defence mechanism
- Bacteria use restriction endonucleases to cut the DNA of bacteriophages
- Many venoms have their origins in antimicrobial peptides.
- Bacteriocidal chemical defense mechanisms are produced by fungi and vice vera
- The classical activation pathway of complement evolved as an adjunt to enhance the lectin and alternate pathways.
True or false. Neutrophils have neutral staining intracytoplasmic granules?
True
What can be classified as a polymophonuclear cells?
Eosinophils and heterophils
True or false. Collectins bind carbohydrates on various micro-organisms?
True
Which mechanism is used by pathogens to evade the action of complement?
Staphylococci bacteria can produce protein A which binds complement.
Name an antigen presenting cell
B lymphocyte
Name a step that occurs in macrophages during phagocytosis?
Fusion of the phagosome with lysosomes to form a phagolysosome
What is adipose tissues?
Modified loose connective tissue- innactive fibroblasts are modified into adipocytes.
- Consists of lobules of adiposytes separated by loose connective tissue
- Can be white adipose tissue or brown adipose tissue
Name the 3 different types of cartilage?
Hyaline cartilage
elastic cartilage
fibrocartilage
Where are cartilage cells found?
Lacunae
What are chondrocytes?
Mature cartilage
What are chondroblasts?
Growing cartilage (from matrix)
What is matrix made from?
60-80% water
12-25 % GAGs
8-15% Fibres (collagen II or fibrous adhesive proteins)
