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Flashcards in Histology - Cardiovascular/Respiratory Deck (86)
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What is blood? What is it made up of?

Blood is fluid connective tissue. Cellular component = 44% (erythrocytes = 43%, leucocytes = 1%) + fluid component (plasma = 56%)


What is plasma? What is it made up of? What is serum?

Plasma = blood minus the cells. Made up of water, salts + minerals, plasma proteins (albumin etc.), hormones + clotting factors. Serum = plasma minus clotting factors


What are erythrocytes? What is their shape? Where are they created and destroyed? How is the cell shape maintained?

Erythrocytes = red blood cells. 4 to 6million per mL of blood + last for 4 months. Anculeate, biconcave discs, 6.5-8.5 um in diameter, haemoglobin = major protein. Created in liver (foetus) + bone marrow. Destroyed in liver + spleen. Cell shape maintained by endoskeleton attached via major protein called spectrin.


What are the 3 categories of leucocytes (white blood cells)? What types of white blood cells are in each category?

- Granulocytes (contain visible granules):

- Neutrophils (40-75%)

- Eosinophils (-5%)

- Basophils (-0.5%)

- Agranulocytes (no visible granules):

- Lymphocytes (20-50%)

- Monocytes (1-5%)

- Platelets (cell fragments, not cells)


What are neutrophils? How do they appear? What is their role? 

- Commonest white blood cell + granulocyte

- Multi-lobed nucleus, granular cytoplasm, 12-14um in diameter, contain myeloperoxidase (needed in order to conduct respiratory burst to engulf macromolecules)

- Primary phagocytes = engulf + destroy foreign macromolecules

- Circulate in blood + invade tissue spaces



What are the 3 types of cytoplasmic granule?

- Primary = lysosomes, contain myeloperoxidase + acid hydrolases

- Secondary = contain specific substances secreted to mobilise inflammatory mediators

- Tertiary = contain gelatinises (break down proteins) + adhesion molecules. Aid neutrophil out of blood vessel + through tissue 


What are eosinophils? How do they appear? What is their role? 

- Make up 1% of total number of white blood cells, numbers increase in parasitic infections

- Bi-lobed nucleus, 12-17um in diameter, distinctive large red cytoplasmic granules with crystalline inclusions

- Play a role in phagocytosis + response to allergens but have antagonistic action to basophils + mast cells 



How do eosinophils appear under an electron microscope? 

- Have lozenge-shaped granules with crystalline cores

- Particular affinity for antigen/antibody complexes 

- Have receptors for immunoglobulin E on surface

- Inhibit mast cell secretion + neutralise histamines, so important role in infammatory responses


What are basophils? How do they appear? What is their role? 

- 0.5% of white cells

- 14-16um diameter, bi-lobed nucleus + prominent dark-blue staining cytoplasmic granules (contain histamine)

- Involved in inflammatory reactions + act to prevent coagulation and agglutination 


How do basophils appear under an electron microscope? What are they thought to be the circulating form of? 

- Have receptors for IgE, release histamine = results in immediate hypersensitivity reaction (anaphylaxis)

- Thought to be circulating form of mast cells


What are the two types of lymphocytes?

- Lymphocytes = small + appear mainly as nucleus. Two types: 
- B cells = become plasma cells + secrete antibodies. Develop in bone marrow

- T cells = involved in cell-mediated immunity. Develop partly in thymus

- You cannot distinguish between T and B cells. All lymphocytes look the same on H&E


What are the 3 types of T cells? What are NK cells?

- T Helper (TH) cells = help B cells + activate macrophages 

- T Cytotoxic (TC) cells = kill previously marked target cells

- T Suppressor (TS) cells = suppress TH cells, so suppress immune response 

- Natural Killer (NK) cells = mainly kill virus infected cells


What are monocytes? How do they appear? What is their role?

- Immature cells, circulate briefly in blood

- Reniform (kidney) shaped nucleus, 15-20um diameter

- Differentiate into one of several cell types within tissue, some become antigen presenting cells so pass antigen fragments to lymphocytes

- Major phagocytic + defensive role

- Although agranular, have small cytoplasmic granules


What do monocytes differentiate into? 

- Tissue macrophages = everywhere

- Kupffer cells = liver

- Osteoclasts = bone

- Antigen presenting cells = everywhere

- Alveolar macrophages = lung



What are platelets? Where do they derive from? How do they appear? What is their role?

- Fragments of cells derived from megakaryocytes in bone marrow

- 1-3um diameter, surrounded by cell membrane + contain vesicles with coagulation factors

- Responsible for clotting of blood


What is haematopoesis? Where do all blood cells stem from? What does this stem into? What do these two cells eventually give rise to?

Formation of blood cells. All stem from multipotential haematpoetic stem cell (haemocytoblast). Goes to common myeloid progenitor + common lymphoid progenitor. Common myeloid progenitor results in platelets, erythrocytes, mast cells, basophils, neutrophils, eosinophils + monocytes. Common lymphoid progenitor gives rise to lymphocytes. Don't need to know whole table


Image of bone marrow.

- Bony trabeculum = piece of haematopoietic bone marrow (long, pink)

- Adipocytes = white empty spaces 

- Haematopoietic stem cells = inbetween adipocytes


Where do all blood cells come from in adults? What are the 3 types of haematopoeitic stem cells?

All blood cells from in haematopoeitic bone marrow (not in children). Myelon = lies next to bone + give rise to white blood cells, erythron = lies inbetween bony trabeculae + give rise to red blood cells, megakaryocytes = lies in between bony trabeculae + give rise to platelets



What happens in erythropoeisis? What is it mediated by?

Erythropoeisis = forming erythrocytes. Proerythroblast to reticulocyte (step just before production of red blood cells). Cell matures +  reduces in size, Hb increased (early = basophilic, later = eosinophilic), loss of organelles. In final stage, nucleus is lost. Mediated by the hormone erythropoeitin (EPO)


What happens in granulopoeisis? 

Granulopoeisis = formation of granular cells, similar for neutrophils, eosinophils + basophils. Increasing number of granules, increasingly complex shape of nucleus. Bone marrow contains large pool of stored mature neutrophils to be released during times of infection. Lymphocytes = only mature blood cells capable of cell division 


What proportion of of blood cells are white?

- A. 56%

- B. 75%

- C. 10%

- D. 43%

- E. 1%



Where are these cells formed in adults? 
- A. Bone marrow - phalanges

- B. Bone marrow - ribs

- C. Liver

- D. Spleen

- E. Thymus




Which is the predominant leukocyte? 
- A. Basophil 

- B. Eosinophil 

- C. Lymphocyte

- D. Monocyte

- E. Neutrophil



Numbers of which cell type increase in patients with worms?
- A. Basophil

- B. Eosinophil

- C. Lymphocyte

- D. Monocyte

- E. Neutrophil





Where do B-lymphocytes mature in adults? 
- A. Blood 

- B. Bone marrow

- C. Bowel

- D. Brain

- E. Bursa of Fabricus



Which statement regarding this cell is true? 
- A. Contains Charcot-Layden crystals

- B. Has IgE receptors 

- C. Produces histamine

- D. Phagocytosis bacteria

- E. Secretes antibodies

B and C


Which statement concerning this cell is true?

- A. It has IgE receptors 

- B. It neutralises histamine 

- C. It secretes antibodies 

- D. It's the most abundant leucocyte

- E. It will become a mast cell


Monocytes become which of the following? 
- A. Chondroblasts

- B. Fibroblasts

- C. Hepatocytes

- D. Kupffer cells

- E. Osteophils



Which of these is the multipotential haematopoeitic stem cell? 
- A. Haemocytoblasts

- B. Megakaryocyte

- C. Myeloblast

- D. Promyelocyte

- E. Reticulocyte




Which of these gives rise to platelets? 
- A. Haemocytoblast

- B. Megakaryocyte

- C. Myeloblast

- D. Promyelocyte

- E. Reticulocyte