Blood Flashcards
List the functions of blood
- Transport respiratory gases (O2 &CO2)
- Transports nutrients, electrolytes, vitamins, hormones, lipids, wastes
- Regulation (Homeostasis) of body temperature, pH, ion concentration, osmolality, hormones
- Hemostasis to prevent blood loss
- Immunity (leukocytes)
How does blood regulate body temperature?
Through the re-distribution of heat
Carries heat away from where it is being produced (e.g. during exercise)
What is hemostasis?
Complex and efficient pathways to prevent blood loss from a damaged blood vessel and tissue repair
Platelets + Coagulation
How much blood does an average adult have?
Average: 5L
Men: 5-6L
Women: 4.5-5.5L
Why is blood 5x more viscous than water?
Blood consists of water, dissolved proteins & formed elements
What are the components of blood?
RBC
WBC
Platelets
Plasma
What constitutes of formed elements?
Cellular components:
RBC, WBC, Platelets
Plasma composition in %
Plasma proteins 7%
Other solutes 1%
Water 92%
List the composition of plasma proteins (in order of their abundance, from mosts to least)
- Albumin (60%)
- Globulins (35%)
- Fibrinogen (4%)
- Regulatory proteins (<1%)
% don’t need to know
Purpose of albumins
(plasma protein)
- major contributors to osmotic pressure of plasma (maintain)
- tpt lipids & steroid hormones
Purpose of globulins
(plasma protein)
- tpt ions, hormones, lipids
- immune function (immunoglobulin)
Purpose of fibrinogen
(plasma protein)
- Essential component of clotting system; can be converted to insoluble fibrin
What are regulatory proteins?
Enzymes, proenzymes, hormones
What are the other solutes in plasma?
- Electrolytes
- Organic nutrients
- Organic wastes
What are the major plasma electrolytes?
- NA+ (sodium)
- K+ (potassium)
- CA2+ (calcium)
- Mg2+ (Magnesium)
- Cl- (Chloride)
- HCO3- (bicarbonate)
- HPO4- (hydrogen phosphate)
- SO42- (sulfate ion)
What do electrolytes in the plasma do?
Ions contribute to osmotic pressure of body fluids
What are the organic nutrients in the plasma used for? What do they include?
Used for ATP production, growth, maintenance of cells
Includes:
1. Lipids (fatty acids, cholesterol, glycerides)
2. Carbs (primarily glucose)
3. Amino acids
What happens to the organic wastes in plasma? What do they include?
Carried to sites of breakdown/excretion
Includes:
1. urea
2. uric acid
3. creatinine
4. bilirubin
5. ammonium ions
Normal hematocrit levels for males & females
Males: 40-54%
Females: 37-47%
Normaal hemoglobin levels for males & females
Males: 14-17 g Hb/dL
Females: 12-16 g Hb/dL
What does hemoglobin value reflect?
The oxygen-carrying capacity of RBCs
What is hematocrit?
% of total blood volume that is occupied by packed (centrifuged) RBCs
Breakdown the % of a complete blood count (Plasma, WBC, RBC)
Plasma: ~58%
WBC: <1%
RBC: 42%
Name the differential WBCs
- Neutrophils
- Eosinophils
- Basophihls
- Lymphocytes
- Monocytes
List the differential WBCs according to abundance, starting with the most abundant.
- Neutrophils (50-70%)
- Lymphocytes (20-40%)
- Monocytes (2-8%)
- Eosinophils (1-4%)
- Basophils (<1%)
Don’t need to know %
List the function of RBCs
- Respiratory gas transport
contains Hb to tpt O2
contains carbonic anhydrase to tpt CO2 - buffer pH in blood
Shape of RBCs
Biconcave discs
Size of RBCs
Diameter: 7.5µm
Thickness: 2.5-0.5µm
Adaptation of RBC
- Large surface to volume ratio which optimises gas exchange and allows easy diffusion of O2
- Flexibility -> allows RBCs to move smoothly through capillaries (small: 3-4µm diameter) through stack formation
Composition of RBCs
Mainly Hb
No nucleus
No organelles
How many % of the formed elements in blood are RBCs?
> 99%
Remaining ~1% are WBC & platelets
RBC lifespan
100-120 days
How much % of RBC content is Hb?
> 97%
How does more Hb in blood help?
More Hb = inc O2 tpt capacity = less work for the heart as a pump
How does RBCs get energy?
Glycolysis (anaerobic) for ATP -> fuel active tpt mechanisms to maintain ionic conc. within cell
Lack mitochondria (bc produicing ATP requires O2 -> not efficient bc consumption of tpted O2)
What does carbonic anhydrase do?
Converts CO2 into bicarbonate (HCO3) -> primary form of CO2 in blood
Chemical eqn of conversion of CO2 in the presence of carbonic anhydrase
CO2 + H2O <-> H2CO3 <-> H+ + HCO3-
H2CO3 is carbonic acid -> not stable so degenerates
What does it mean for the cell that it has no nucleus?
No nucleus mean s no ribosomes
No repairs or division/synthesis of cellular proteins/enzymes
E.g. damage/wear & tear from squeezing through capillaries
What are the two portions of Hemoglobin?
Globin portion
Heme molecule
What is the globin portion of hemoglobin?
4 folded polypeptide chains (2 alpha + 2 beta chains) -> each chain contains a single heme molecule
What is the heme molecule?
Pigment complex
1 iron -> 1 O2 molecule can bind
Binding is weak & reversible
How many molecules of oxygen can one Hb molecule transport?
4
Sites of Erythropoiesis
Fetus: yolk sac, developing liver & spleen
Children: bone marrow in many different bones
Adults: bone marrow in ribs, sternum, vertebrae, pelvis & upper end of long bones
Steps of Erythropoiesis
- Hematopoietic stem cells in bone marrow give rise to proerythroblasts
- Proerythroblast develop into erythroblasts
- Ribosome synthesis occurs in early erythroblasts to make Hb
- Hb accumulates in late erythroblasts & normoblasts
- Ejection of nucleus from normoblasts and formation of reticulocytes
- Reticulocytes continue Hb synthesis, leave bone marrow & complete differentiation to mature RBC in blood
What is reticulocyte count indicative of?
Indicative of erythropoiesis
Reticulocyte count normal range
0.8-1.5%
What does erythropoiesis require?
- Iron
- Vitamin B12
- Folic acid/folate
- Proteins
- Lipids
- Carbs
How much iron does a normal diet provide and how much is absorbed?
Provides 10-15 mg/day
10% absorbed
How much iron is lost per day?
0.5-1.0mg in males
greater in females
How to treat anemia?
Iron supplement, folic acid, Vitamin B12