IC1 Blood Flashcards
1
Q
Blood collected w anticoagulants (e.g., heparin, citrate, EDTA) consists of:
A
Plasma (55%)
Formed elements
- Buffy Coat (1%)
- Erythrocytes (45%)
2
Q
Plasma contains:
A
Water (92%)
Proteins (7%) made in the liver
- Albumin - transport lipids + osmotic pressure
- Immunoglobulins - transport + immune function + clotting
- Fibrinogen - clotting
- Regulatory proteins (enzymes, hormones)
Solutes (<1%)
- Ions/electrolytes - osmotic pressure, vital cell activity
- Organic nutrients (e.g., glucose, carbohydrates, AAs, fatty acids, lipids) - ATP pdn, cell growth and maintenance
- Organic metabolic waste (e.g., urea, uric acid, ammonium, creatinine, bilirubin)
- Gases
3
Q
Buffy coat contains:
A
- Leukocytes (NLMEB)
- Platelets/Thrombocytes
4
Q
Compare amount of erythrocytes in males vs females
Compare hematocrit percentage.
A
Males more because
- Stimulatory effect of androgen on bone marrow, enhances erythropoiesis
- No monthly blood lost during menstrual period
Hematocrit - RBC vol / total blood vol
- Male: 46%
- Female - 42%
5
Q
Low hematocrit may suggest
A
anemia
6
Q
High hematocrit may suggest
A
polycythemia
7
Q
Blood collected w/o anticoagulants consists of:
A
- Serum (protein rich, lacks fibrinogen)
- Blood clot (fibrin-containing network trapping blood cells)
8
Q
Blood characteristics:
- Volume
- % body weight
- pH
- Color - oxygenated and deoxygenated
- Temp
A
- Volume: 5-6L (M), 4-5L (F)
- 8% of body weight
- pH 7.35-7.45 (slightly alkaline)
- Colour: scarlet/bright red (oxy), deep/dark red (deoxy or carbaminogemoglobin)
- Temp: 38dc (slightly hotter than body temp)
9
Q
Blood tissue type
A
Connective tissue
*Comprise cells + gels + fibres
*Blood is the ONLY fluid tissue in the body
10
Q
Functions of blood
A
- Transportation (O2, CO2, nutrients, wastes, hormones)
- Regulation (body temp, pH, ion composition of interstitial fluids)
- Protection (blood clotting, immune function)
11
Q
What is a convenient method to examine blood cells
A
Blood smear
- view under microscope to reveal components of formed elements (RBCs + WBCs)
12
Q
Red blood cells
- Lifespan
A
- Generated in red bone marrow, enter circulation for 3-4 months
- Worn out RBCs removed by macrophages or destroyed in liver, spleen or bone marrow
13
Q
Red blood cells
- Shape
- Diameter and thickness
- Explain advantages of its shape
A
Biconcave disc
- diameter 6-8um
- thickness 2um
=> Large SA for easy diffusion of O2 and nutrients
=> Allow flexibility to enter/exit capillaries (3-4um)
=> Smooth flow through stack formation
14
Q
Red blood cells
- Histology
A
Lack nuclei and most organelles
15
Q
Red blood cells
- Function
A
- Respiratory gas transport
- Buffer pH in blood
16
Q
Red blood cells
- components that transport respiratory gases
A
Hemoglobin (Hb) - transports O2
Carbonic Anhydrase - transports CO2
17
Q
Red blood cells
- Hemoglobin
A
Globin + Heme
Globin:
- 4 folded polypeptide chains, 2a and 2B chains
- each chain binds 1 heme group
Heme:
- Pigment
- Each heme group contains 1 iron, which binds 1 O2 molecule
18
Q
Red blood cells
- How many molecules of O2 does one hemoglobin transport?
A
4
19
Q
Red blood cells
- Explain why small reduction in hematocrit can have large effect on the body
A
1 RBC transports 10^9 O2 molecules, hence small reduction in hematocrit can result in large reduction in oxygen in the body
20
Q
Red blood cells
- What is sickle cell disease?
A
Sickle cell disease
- mutation of Hb B chain, result in HbS
- HbS molecules polymerize and aggregate when deoxygenated (low O2 conditions), aggregate to CRESCENTS that rupture the RBC membrane
- SIckled erythrocytes are spindle shape
- Incr blood viscosity
- Shorted lifespan
HbS carrier is resistant to malaria since harder for parasite to infect the RBC
21
Q
What are the two types of leukocytes?
A
- Granulocytes (neutrophils, eosinophil, basophil)
- Agranulocytes (lymphocytes, monocytes)
22
Q
Neutrophils
- Lifespan
A
10h
23
Q
Neutrophils
- Shape, size
A
12-15um in diameter (bigger than RBCs)
24
Q
Neutrophils
- Histology
A
Polymorphonuclear (PMN)
- Nucleus has 3-5 obes connected by fine strands
Granulocyte
- Cytoplasm packed with pale “neutral coloured” granules containing bactericidal compounds
25
Neutrophils
- Functions
- Highly mobile, first WBCs to arrive at acute inflammation/phagocytosis
- Specialized in attacking and digesting bacteria that have been 'marked' for destruction
- Increase neutrophils seen in bacterial infection
26
Eosinophils
- Lifespan
Minutes to days
Move to tissue after a few hours
27
Eosinophils
- Shape/size
Similar to neutrophils: 12-15um diameter (larger than RBCs)
28
Eosinophils
- Histology
Polymorphonuclear (PMN)
- bilobed nucleus
Granulocyte
- reddish-orange granules
29
Eosinophils
- Function
- Phagocytosis antibody-coated bacteria, protozoa, cellular debris
- Exocytosis of toxic compounds onto surface of target
- Increase in parasitic infection
30
Basophils
- Histology
Polymorphonuclear (PMN)
- usually bilobed, obscured
Granulocyte
- Deep purple/blue granules
31
Basophils
- Functions
- Migrate to injury sites to discharge contents of the granules (e.g., histamine, heparin) that enhance local inflammation
- Involved in inflammatory reactions during immune response, as well as in acute and chronic allergic reactions (e.g., anaphylaxis, asthma(
32
Monocytes
- Shape/size
13-25um diameter (almost twice as big as RBC)
33
Monocytes
- Histology
- Large nucleus, eccentrically placed, oval or kidney-shaped
34
Monocytes
- Lifespan
Stay in circulation for 24h before entering other tissues to become macrophages
35
Monocytes
- Function
- Generate tissue macrophage
- Phagocytosis and digest protozoa, virus, aged cells
- Antigen presentation
36
Lymphocytes
- Shape/size
Slightly larger than RBCs (6-8um)
37
Lymphocytes
- Histology
Thin halo of cytoplasm around a relatively large nucleus
38
Lymphocytes
- Can T and B lymphocytes be differentiated on blood smear?
No
39
Lymphocytes
- Where do T and B lymphocytes mature?
T lymphocytes from red bone marrow migrate to thymus for maturation
B lymphocytes mature in the red bone marrow
40
Platelets
- Normal range
200,000 - 400,000 /uL
Thrombocytopenia: Platelet count <100,000 cells/mm3 (100 x 109/L)
41
Platelets
- shape/size
flattened disk-like cell fragments of about 1-4um
megakaryocyte 160um => give rise to 2000-3000 platelets
42
Platelets
- lifespan
9-12 days (~7 days?)
Removed by splenic phagocytes
43
Platelets
- Histology
- non-nucleated cell fragments
- purple-stained and granular appearance on blood smear
44
Red bone marrow is the site for ______ and ________
Hematopoiesis
- Meshwork of vascular sinuses and highly branched fibroblasts with the interstices packed with hematopoietic cells that produce billions of RBCs, WBCs, and platelets daily
Removal of worn-out RBCs
- Along with spleen and liver
45
Red bone marrow is found in?
Flat, irregular bones: sternum, vertebrae, hip bones, ribs
Ends (epiphysis) of adult femur, humerus
As we age, hematopoiesis becomes restricted to the flat/irregular bones
Marrows in the shaft/diaphysis of long bones become yellow bone marrow (fat tissue)
46
Erythropoiesis
- Replacement of RBC: how many RBC per second
2-3million RBC /sec
47
Erythropoiesis
- Where?
Fetus: yolk sac, then liver, spleen, lymph node
<5y: all bone marrow
5-20y: bone marrow in ribs, sternum, vertebrae, proximal ends of long bones
>20y: bone marrow in ribs, sternum, vertebrae
48
Erythropoiesis control
- Erythropoietin (growth factor) is released by _____
- It's release is regulated by ______
- What are some conditions that might trigger erythropoietin release?
- Kidney (90%), Liver (10%)
- Regulated by *tissue oxygenation* (low O2 to kidney => more erythropoietin release => incr rate of erythropoiesis) *Negative feedback
- hypoxia, decreased O2 availability, incr tissue demand for oxygen, anemia, reduced blood flow to kidney, blood donation
49
Erythropoiesis
Functions of Erythropoietin:
- Stimulate hematopoietic stem cells to form proerythroblasts
- Enhances proliferation rate of proerythroblasts and erythroblasts
- Enhances Hb synthesis
- Incr RBC pdn 10 fold
50
Erythropoiesis process
Hematopoietic stem cells in red bone marrow give rise to proerythroblasts which develop into erythroblasts in 3 steps
1. **Ribosome synthesis** in early erythroblasts
2. **Hb accumulation** in late erythroblasts and normoblasts
3. **Ejection of nucleus** and formation of reticulocytes (immature RBCs)
=> Reticulocytes continue Hb synthesis, leave bone marrow and differentiate to mature erythrocytes in the blood
51
Normal reticulocyte range
What might high/low reticulocyte count suggest?
Normal range: 0.8-1%
High: acute blood loss, hemolysis, thus resulting in erythropoiesis occurring higher than normal (reticulocytosis)
Low: suggests defect erythropoiesis, failure of bone marrow such as aplastic anemia
52
Breakdown products of RBC:
Iron
- recycled, reused in bone marrow OR stored in the liver as ferritin or hemosiderin
- iron is bound to transferrin and released to blood from liver as needed for erythropoiesis
Globin
- metabolizes into amino acids and released into circulation
Heme
- Degraded to bilirubin, excreted via liver and bile into urine and fece
53
Dysregulated erythropoiesis results in either ______ or _______
Anemia
Polycythemia
54
Anemia is defined as:
Reduction below normal capacity of the blood to carry oxygen due to reduction of erythrocyte numbers and/or reduction of Hb functions
- Low hematocrit
- Low RBC counts
55
Types of anemia include:
- Nutritional anemia (lack of iron, folic acid, vit B12, intrinsic factor)
- Aplastic anemia (bone marrow failure)
- Renal anemia (lack of EPO due to kidney disease)
- Hemorrhagic anemia
- Malaria (plasmodium falciparum ruptures RBC)
- Sickle cell anemia (mutation in B globin gene, crescent/spindle shape RBC that rupture)
- Erythroblastosis fetalis (Rh+ RBC of second fetus destroyed by anti-Rh antibodies of Rh- mother)
- Thalessemia (low pdn of Hb)
56
Consequence of anemia
- Reduction in RBC conc. result in less viscous blood
- Blood flows faster through the tissues releasing insufficient O2
- Resulting hypoxia widens blood vessels and reinforces the effect
=> Increased workload for the heart could lead to cardiac arrest
57
Polycythemia is defined by
Excess in circulating erythrocytes
- elevated hematocrit
- elevated RBC count
58
Primary VS Secondary Polycythemia
Normal RBC: 5 x 10^9 RBC/ml
Primary: 7-8 x 10^9 RBC/ml
- Caused by tumor or tumor-like condition in bone marrow
Secondary: 6-7 x 10^9 RBC/ml
- Erythropoietin-induced, adaptive mechanism to improve O2 carrying capacity of the blood
- E.g., high altitudes
Other conditions such as dehydration can elevated hematocrit as well
59
Consequence of polycythemia
- very viscous blood
- potential plugging of capillaries
- insufficient O2 delivery to tissues
=> incr workload for heart, lead to cardiac arrest as well
60
Complete blood count components
- Hb
- MCV: mean corpuscular volume (size)
- MCH: mean corpuscular hemoglobin (color)
- MCHC: mean corpuscular hemoglobin concentration
- RCW: red cell distribution width (anisocytosis, iron deficient anemia)
61
Leukocyte disorders
- Leukopenia
Too few leukocytes, lead to opportunistic infections
May be caused by radiation, chemotherapy, chemicals, viral infections etc.
62
Leukocyte disorders
- Leukocytosis
Elevated leukocytes
Can be a normal response to bacterial or viral invasion
Or can indicate cancer of WBCs
63
Leukocyte disorders
- Leukemia/Lymphoma
Cancers of white blood cells
Leukemia: liquid cancer in blood
Lymphoma: liquid cancer in lymphatic system - bone marrow
WBCs produced are not functional, causing immune deficiency => infections, anemias, hemorrhage
Treatment: irradiation, chemotherapy, bone marrow transplant
