Blood

Question 1

Composition of blood

Answer 1

• Plasma: water, electrolytes, plasma proteins, hormones, fats, aa, vitamins, carbs, lipoproteins, etc
• RBCs (40-45%)
• WBCs + Platelets

If you add an anticoagulant and centrifuge, then it sediments into layers due to different densities: RBC > WBC > plasma

Question 2

Cytology of RBC

Answer 2

• No nucleus or most organelles
• Hemoglobin –> acidophilic
• Biconcave disk maximizes SA for respiratory exchange
• Flexible, elastic membrane to allow extravasation
• Spectrin & actin for cytoskeleton

Question 3

Life span & function of RBCs

Answer 3

• Life span: ~120 days; surface area decreases w age–> rigid sphere
• Fxn:
  
  • oxygen & CO2 transport by providing an environment for hemoglobin (globin + iron-containing heme)
  • has some enzymes for glycolytic & hexose monophosphate biochemical pathway

Question 4

Blood O₂ content in each type of bv: venous, lung, arterial, capillaries

Answer 4

The amount of O₂ is highest in arteries and lung capillaries

Less in capillaries, where exchange occurs between blood & tissue

Least in venous

Question 5

Hereditary spherocytosis

Answer 5

Defect in spectrin or ankyrin binding of spectrin –> round/convex, brittle RBC cell membrane

–>Gets trapped in splenic microcirculation and destroyed in large numbers (hemolysis).

Question 6

Anemia

Answer 6

Iron deficiency from impaired RBC formation or excessive RBC destruction -> Inadequate hemoglobin –> weakness, pallor, breathlessness.

Hypochromic, microcytic RBCs.

Question 7

Hemolytic anemia

Answer 7

RBCs are structurally abnormal and thus liable to damage, so they’re removed prematurely and in excess by the spleen

Seen in hereditary spherocytosis and sickle cell anemia (point mutation in hemoglobin gene)

Question 8

Reticulocytes

Answer 8

Less mature RBCs released from bone marrow up to 2 days ago

Question 9

Cytology of reticulocytes

Answer 9

Contains residual RNA –> blueish color

Red-blue in Wright stain, Blue in methylene blue

Makes up 1-2% of red blood cells

Question 10

Neutrophils/neutrophilic granulocytes cytology

Answer 10

• Prominent, lobed nucleus
  
  • Less mature neutrophils have a band-shaped or horse-shoe nucleu
• Most numerous WBC in an adult
• Azurophilic (primary) & Specific (secondary) granules
• Glycogen, filaments, microtubules

Question 11

Azurophilic (primary) granules

vs

Specific (secondary) granules

Answer 11

• Azurophilic granules:
  
  • Large, electron-dense
  • Contain antibacterial substances for innate immunity.
    
    • Ex) Myeloperoxidase (can be stained), elastase, cathepsins, defensins
• Specific granules
  
  • Myeloperoxidase-negative
  • Proteolytic enzymes secreted into extracellular environment. Ex) lactoferrin
  • Variable size, shape, density

Question 12

___ granules appear first during neutrophil formation, but as the cell matures, their number falls and __ granules becomes twice as numerous.

Answer 12

Primary first

Secondary next

Question 13

Frq of neutrophils

Answer 13

lives ~1-4 days, but half-life in blood is only 6-8 hours. It moves into the tissues in response to infection to tissue damage (myocardial infarct)

Question 14

Functions of neutrophils

Answer 14

Active phagocytes against microorganisms, esp bacteria

Question 15

Bone marrow will release more neutrophils in resonse to stimuli such as

Answer 15

bacterial infection, tissue necrosis, etc.

Question 16

Neutrophil phagocytosis

Answer 16

1. Chemotaxis attracts the neutrophil to devitalized tissue, bacteria, foreign bodies, complement components
2. Blood borne antibody (IgG) to bind to surface antigen on bacteria
3. Complement C₃b binds Fc end of the antibody to activate complements, or neutrophil binds it (opsonization) for phagocytosis.
4. Takes up particles in a phagosome
5. Phagosome fuses with neutrophil granules (esp primary)
   
   1. Bacteria’s killing is enhances by hydrogen peroxide & superoxide
   2. Forms a residual body of degraded material

Question 17

Eosinophils

Answer 17

• Most have bilobed nucleus (N)
• Ovoid-shaped granules (G)
  
  • Stain bright orange in a Romanowsky stain
  • In an EM slide, you can see a dense filamentous core of major basic protein (MBP) called crystalloids (C)
  • Contains lysosomal enzymes

Question 18

Eosinophils circulate for ~8hrs.

What is eosinophils’ function?

Answer 18

Increased in parasitic infections (attacked by major basic protein); allergic reactions to stimuli like pollen; some drug drug reactions

Phagocytoses antigen-antibody complexes and inactivates mediators of inflammation like Leukotrienes.

Question 19

Basophils cytology

Answer 19

• Nucleus has 2-3 lobes, but often hard to see because of
• Large, dark purple specific granules containing
  
  • heparin (anticoagulant)
  • histamine (vasodilator)
  • leukotriene, serotonin, eosinophil chemotactic factor

Question 20

The least numerous WBC in peripheral blood is

Answer 20

Basophils

Question 21

Difference between basophils and mast cells

Answer 21

Mast cells are in the bone marrow and tissue

Basophils are in peripheral blood

Question 22

Basophil function

Answer 22

Hypersensitivity reaction:

1. Bind IgE antibody
2. When exposed to the corresponding antigen, it will release vasoactive substances

Question 23

Largest cell in peripheral blood

Answer 23

Monocyte

Question 24

Monocytes are from bone marrow promonocytes; they spend ~1wk in blood and migrate into tissue where they become ___ or ___. They are the largest cell in the peripheral blood.

Answer 24

Tissue macrophages or histiocytes

Question 25

Appearance of monocytes

Answer 25

* Large nucleus, usually in an eccentric position * Pale cytoplasm with fine granules * Microvilli on cell membrane

Question 26

Function of monocytes

Answer 26

* Enters the tissue to differentiate into macrophages or tissue histiocytes * Helps with antigen interaction of immunocompetent cells

Question 27

Lymphocytes

Answer 27

Single, deeply-stained, spherical nucleus that takes up most of the cell; thin rim of lightly basophilic cytoplasm. Includes T cells, B cells, and NK cells.

Question 28

T cells

Answer 28

* Processed by the **thymus** and participate in cell-mediated immunity (e.g. graft rejection) * **Cytotoxic T cells** elaborate cytotoxic agents, making lymphokines. * **Memory T cells** survive for yrs/decades

Question 29

B-cells

Answer 29

* Have **immunoglobulin** on their cell membrane to aid in **humoral or antibody-mediated immunity** * Divide & differentiate into **plasma cells** in tissue * Some are **memory cells**

Question 30

Plasma cells

Answer 30

derived from B-cells; have an eccenrically placed nucleus **Produces antibodies (immunoglobulins**)

Question 31

NK cells

Answer 31

lack the surface antigens of T and B cells, so they don't rquire prior stimulation to attack virus-infected or tumor cells

Question 33

What are the **mononuclear WBCs/agranulocytes**?

Answer 33

Monocytes & lymphocytes

Question 34

**Neutrophilia** (increased circulating neutrophils) indicates \_\_\_ **Eosinophilia** indicates \_\_\_\_ **Lymphocytosis** indicates \_\_\_\_

Answer 34

Neutrophilia -\> bacterial infection Eosinophilia -\> parasitic infections, some allergies Lymphocytosis -\> viral infections

Question 35

**Neutropenia/agranulocytosis** (reduced # of circulating neutrophils) can be caused by

Answer 35

**bone marrow damage,** such as in a tumor or in chemotherapy **diseases** (e.g. autoimmune ones, splenomegalies)

Question 36

**Lymphopenia (**reduced # of lymphocytes) are associated with some rare inherited diseases, infections, and autoimmune diseases.

Answer 36

E.g. lupus, typhoid, brucellosis

Question 37

Leukemias

Answer 37

Maligant proliferation of white cell precursors in bone marrow --\> vast # of WBCs that spill over into the blood

Question 38

chronic vs acute leukemias

Answer 38

**Chronic leukemias**: well-differentiated proliferating cells; slow progression; bone marrow still produces some normal elements **Acute leukemias:** proliferating cells are primitive precursor (blast cells); rapid progression; failure of bone marrow

Question 39

Platelets are derived from

Answer 39

Bone marrow megakaryotcytes

Question 40

When platelets become activated, the microtubular system...

Answer 40

Squeezes the granules to the center, releasing the contents, and triggering the coagulation system.

Question 41

Function of platelets

Answer 41

**Hemostasis** (stop bleeding) by aggregating and releasing contents of alpha & dense granules --\> **coagulation cascade** involves plasma factors to form a blood clot.

Question 42

Steps of hemostatsis

Answer 42

1. **Platelet's membrane glycoproteins** adhere to **von Willebrand factor** on exposed collagen on damaged blood vessels 2. Platelet actin, myosin, and mts cause reversible **platelet moulding and adhesion** along a broad surface 3. **Releases granule contents through the canalicular system** and synthesize thromboxane 4. **Thromboxone, ADP, Ca²⁺** mediate adhesion of other platelets 5. Platelet phospholipids (w/ Ca²⁺) activate blood clotting cascade -\> **fibrin formation**

Question 43

Thrombocytopenia

Answer 43

Severe reduction in the # of plate lets --\> spontaneous bleeding looks like a bruises/patches (ecchymoses)

Question 45

Thrombocytosis

Answer 45

Excessive circulating platelets due to a burst of bone marrow hyperactivity after acute blood loss.

Question 46

Name each

Answer 46

A- lymphocyte B- monocyte C- neutrophil D-eosinophil E- basophil

Question 47

Unlike plasma, **serum lacks**

Answer 47

**fibrinogen**, which is formed in clot formation. You get serum by centrifuging blood as is, without anticoagulant.

Question 48

Name these

Answer 48

Neutrohil, eosinophil, basophil

Question 49

Name these

Answer 49

monocyte, lymphocyte

Question 50

Whats the disease?

Answer 50

Hypochromic (pale) and microcytic (small) RBCs, central pallor --\> less hemoglobin than normal --\> iron deficiency --\> **anemia**

Question 51

Hereditary elliptocytosis

Answer 51

autosomal dominant ; self-association of spectrin subunits, defective binding of spectrin to ankyrin, protein 4.1 defects -\> RBCs are oval

Question 52

Anemia, jaundice, splenomegaly, and hemolytic anemia are common clinical features of what two diseases?

Answer 52

spherocytosis and elliptocytosis

Question 54

In sickle cell anemia, **glutamic acid** is replaced by **\_\_\_\_ .**

Answer 54

Valine. -\> Hb S causes **chronic hemolytic anemia** & **obstruction of postcapillary venules.**

Question 55

Difference between agranulocytes and granulocytes

Answer 55

Both have primary granules, but only granulocytes have **specific/secondary granules**

Question 56

A granulocytes are \_\_nuclear.

Answer 56

mononuclear.

Question 57

Hypersegmented (too many lobes) neutrophils indicates

Answer 57

Megaloblastic anemia, resulting from vitamin B12 deficiency