Histology of blood

Question 1

What are the functions of blood?

Answer 1

-Body heat
-Coagulation: clotting
-Defence
-Export
-Food
-Gas exchange
-Hormones

Question 2

What are the main blood cells?

Answer 2

-Erthrocytes
-Leukocytes
-Thrombocytes

Question 3

What is the process of making blood cells?

Answer 3

haematopoiesis, occurs in the bone marrow

Question 4

What are the stem cells that form differentiated blood cells called?

Answer 4

Haematopoietic cells

Question 5

Why are Haematopoietic cells not pluripotent?

Answer 5

Cannot differentiate into non-blood cells

Question 6

Where are the sites of haematopoiesis?

Answer 6

-Change as we age
-At birth: All marrow spaces
-Gradually replaced by fat tissue as we age

Question 7

How are mature blood cells released into the blood stream following haematopoiesis?

Answer 7

Crossing the bone marrow/blood barrier

Question 8

How does a network of cell signalling control haematopoiesis?

Answer 8

-Ensures a basal level of cells in the blood
-Monitors shift in populations of cells

Question 9

What is the lifespan of a red blood cell (erthrocyte)?

Answer 9

100 days

Question 10

What are the properties of erthrocytes?

Answer 10

-No nucleus, no DNA
-Concave shape, can be easily deformed to squeeze through capillaries
-More space for haemoglobin to carry oxygen

Question 11

What is the role of white blood cells?

Answer 11

-Defend us from attacking bacteria and viruses
-Tissue turnover
-Ensures body heals correctly after damage

Question 12

What are adaptive immune cells?

Answer 12

Target specific foreign bodies to minimise collateral damage to other cells

Question 12

What are innate immune cells?

Answer 12

Act non-selectively to destroy material deemed as foreign

Question 13

What are the 2 major families of white blood cells?

Answer 13

-Lymphoid cells
-Myeloid cells

Question 14

How are white blood cells grouped by their cytoplasm appearance?

Answer 14

-Granulocytes
-Agranulocytes

Question 15

How are white blood cells grouped on the appearance of their nucleus?

Answer 15

-Mononuclear - single obvious nucleus
-Polymorphonuclear - lobed nucleus

Question 15

What are neutrophils?

Answer 15

-First line of defence
-Important role in directing the immune response
-Most common leukocyte
-Short lived

Question 16

What do neutrophils contain?

Answer 16

-Membrane bound granules containing enzymes and biochemicals which degrade bacteria and recruit other cells

Question 17

What is degranulation?

Answer 17

A pathogen may be internalised into the cell when it contacts these granules or they’re released into the extracellular environment

Question 18

Why are neutrophils designated as polymorphonuclear cells?

Answer 18

They have a lobed nucleus

Question 19

What is the role of eusinophils?

Answer 19

-Protect the body from large invading organisms
-Contains granules with cytotoxic enzymes and biochemicals

Question 19

What are eosinophils?

Answer 19

-Granulocytes
-Common at the mucous membrane of the gut

Question 20

What are basophils?

Answer 20

-Granulocyte
-Rare cell
-Implicated in bodies response to large invading microorganisms and allergic reactions

Question 20

What is eusinophilic peroxidase?

Answer 20

Catalyses the production of cytotoxic substances using hydrogen peroxide

Question 21

What is a eosinophilic cationic protein?

Answer 21

A ribonuclease, toxic to mammalian cells, bacteria and helminths

Question 22

What do basophils have a receptor for?

Answer 22

Antibody called immunoglobin

Question 23

What are the important molecules present in basophils?

Answer 23

-Heparin -Histamine -Seratonin -Enzymes -Anaphylaxis

Question 24

What is the role of histamine?

Answer 24

Vasodilator, increases blood flow to infected tissue

Question 25

What is the role of heparin?

Answer 25

Anticoagulent, ensures free passage to compromised tissue

Question 26

What is the role of seratonin?

Answer 26

Vasodilator, increases vascular permeability

Question 27

What is the role of anaphylaxis?

Answer 27

Induces slow contraction of smooth muscle

Question 28

What are monocytes?

Answer 28

-Mononuclear cells -Unipotent progenitor cell -Migrate into tissues and become a lineage called a macrophage

Question 29

What are macrophages?

Answer 29

-Most important active phagocyte -Mononuclear leukocyte and characterised by horse shoe shaped nucleus

Question 30

What are T lymphocytes?

Answer 30

-Group of molecules on their surface called T cell receptor complex

Question 31

What is the T cell receptor complex?

Answer 31

Allows T cells to recognise and act on specific types of infection by interacting with proteins as MCH complexes

Question 32

What are B lymphocytes?

Answer 32

-Make antibodies -Can prevent antigens in a similar manner to macrophages so can also activate T cells -Also called plasma cells when activated

Question 33

What is the role of antibodies?

Answer 33

Recognise molecules on the surface of pathogens and provide a signal for other more aggressive immune cells to destroy them

Question 34

What are platelets?

Answer 34

-No nucleus -secrete substances and contact with damaged blood vessels to mediate blood clotting and inflammation

Question 35

How do platelets form?

Answer 35

Cytoplasmic budding from a larger cell called a megakaryocyte

Question 36

What are megakaryocytes?

Answer 36

-Bone marrow specific -Produce thrombocytes in bone marrow and migrate to blood

Question 37

What does the presence of megakaryocytes in blood indicate?

Answer 37

-Disease -Useful way of distinguishing between a blood and bone marrow sample

Question 38

What is the role of endothelial cells?

Answer 38

-Lines the entire vascular system -Provide semipermeable barrier controlling passage of water and substances in and out of blood

Question 38

What are endothelial cells?

Answer 38

-Line the blood vessels -Monolayered

Question 39

What is the process of intra/extravasation?

Answer 39

Regulating the barrier to let cells in and out of the blood. Important for allowing leukocytes to reach site of infection