Blood part 2 Flashcards
Factors that influence transcapillary dynamics (4)
Hydrostatic pressure, C.O.P, Capillary permeability, lymphatic drainage
What is edema
accumulation of excess fluid in interstitial spaces
ISF/plasma distribution normal vs Edema
For person w/ edema, more ISF and less plasma
Conditions under which edema can develop
Higher hydrostatic pressure, lower oncotic (C.O.P) pressure, higher capillary permeability, no lymphatic drainage
Increased hydrostatic pressure consequence
Ex. BP is 55 mm Hg at arterial end of cap. and 25 mm Hg at venous end of cap. -> Net filtration pressure of 30 mm Hg at arterial end and Net absorption pressure of 0 mm Hg at venous end
Decreased C.O.P consequence
Ex. BP is 35 mm Hg at arterial end of cap. and 15 mm Hg at venous end of cap. (as usual) but C.O.P is 15 mm Hg instead of 25 mm Hg-> Net filtration pressure of 20 mm Hg at arterial end and Net absorption pressure of 0 mm Hg at venous end
2 possible causes for decreased C.O.P
- Failure to synthesize plasma proteins (ex. liver disease)
2. Severe protein malnutrition
How increased capillary permeability can cause edema
More proteins in ISF, where they exert an oncotic effect. Possible conseq. C.O.P of 20 mm Hg (where fluid tends to go in capillary) and C.O.P of 5 mm Hg (where fluid tends to go in ISF)
How obstructed lymphatic drainage can cause edema
10% fluid filtered out of capillary that is not reabsorbed stays in ISF
Ex. Disease where lymphatic drainage is obstructed
elephantiasis
Elephantiasis cause
Parasite infestation (Filaria nematode) spread by mosquitos. Their larva enters blood and will block lymph nodes –> lymphatic obstruction
3 roles of plasma proteins
1) Determining distribution of fluid between ISF and plasma by controlling transcapillary dynamics
2) Contribute to viscosity of plasma
3) Contribute to buffering power of plasma
Why viscosity of blood is important
It’s a factor that contributes to the maintenance of blood pressure
Specific role of fibrinogen and some globulins
Clotting
Specific role of gamma globulins
gamma globulins = immunoglobulins. SPECIFIC resistance to infection
Specific role of albumin and some globulins
carriers for lipids, minerals and hormones
why iron has to be transported by plasma proteins
free iron is iron oxyde
why hormones have to be transported by plasma proteins
most hormones are fat soluble
3 categories of blood cells (also mention synonyms)
Red blood cells (erythrocytes), Platelets and White blood cells (leukocytes)
Leukocytes : what cells in that category and what they all have
Lymphocytes, Granulocytes, Macrophages, Monocytes –> all nucleated cells
3 categories of blood cells : concentration of each
RBCs: 5x10^6 per microliter, platelets: 250 000 - 400 000 per microliter, leukocytes : 8000 - 10 000 per microliter
3 categories of blood cells : size of each
RBCs : 7.2 micrometer, Platelets : 2-3 micrometer, WBCs : 10 - 18 micrometer
3 categories of blood cells : life span in blood circulation
RBCs : 120 days, Platelets : 7-8 days, WBCs : hours to years
Something unique about leukocytes
Only ones (only cells in blood) that have a nucleus IN THEIR MATURE FORM
what do we call the production of blood cells
hematopoiesis
Where blood cells come from
All derived from a common multipotential (pluripotential) hematopoietic stem cell
what do we call the production of RBCs
erythropoiesis
what do we call the production of platelets
thrombopoiesis
what do we call the production of leukocytes (WBCs)
leukopoiesis
what pluripotential stem cell does and why
Because of an INDUCER (induction by something in their environment - molecule, etc.), self-replicate and differentiate into 3 types of COMMITTED stem cells
what 3 types of committed stem cells do and why
Because of a STIMULANT, 3 types do leukopoiesis, thrombopoiesis and erythropoiesis
General mode of action of stem cells
Upon induction, they do 1) divison and 2) differentiation
What are cytokines
substances (proteins or peptides) released by one cell and affect growth, development and activity of another cell
what do we call cytokines influencing proliferation and differentiation of blood cell precursors
Hematopoietic growth factors (HGFs)
Scheme of differention of pluripotential hematopoietic stem cell
Becomes lymphoid stem cell or myeloid stem cell. Lymphoid stem cells give lymphocytes. Myeloid stem cells (after multiple differentiations) give erythrocytes, granulocytes, basophils, eosinophils, monocytes and platelets (which comme from megakaryocyte)
how can we reconstitute all hematopoietic cell types
Injection of bone marrow stem cells
Prenatal sites of hematopoiesis
yolk sac until 3 months, liver and spleen from month 1 to 9 - peak at 5, skeleton from months 4 to birth - peak at birth
Postnatal sites of hematopoiesis
Distal long bones until 25 years old and axial skeleton whole life
Axial skeleton -> which bones ?
Flat bones of skull, shoulder blade (reminder : = omoplate), pelvis, vertebrae (pl. of vertebra), sternum (between the ribs), ribs, proxymal epiphyses (one of the two epiphyses of a bone) of long bones
Long bones parts (2) (ex. in notes is femur)
2 Epiphyses (sing. = epiphysis) and diaphysis = the middle
Function of erythrocytes
Facilitate transport of respiratory gases between lungs and cells
RBC shape and dimension
biconcave disk (7.7 micrometer long - 7.2 previously so approx. + 2.6 micrometer wide on side and 0.8 micrometer wide in the middle)
Advantage of RBC shape (2)
- Maximal surface area and minimal diffusion distance for its volume (increases efficiency of O2 and CO2 diffusion –> FICK’S LAW)
- High degree of flexibility (allows it to squeeze through narrow - means much long more long than wide, think of elongated - capillaries) 7 micrometer RBC can go through 3 micrometer wide capillary
RBC count in males and females + total count
M : 5.1 - 5.5 x10^6 per microliter F: 4.5-4.8 x10^6 per microliter. Total : 25 x 10^12 / 5L
Note on RBCs
No subcellular organelles : no nucleus, no ribosomes, etc.
Why RBCs need energy and how they make energy
For maintaining their shape, for the Na+/K+ pump, etc.
Use Enzyme systems
First enzyme system why it is needed and what it does
Glycolytic enzymes : Generate energy. No mitochondria so use it to produce ATP
Second enzyme system
Carbonic anhydrase : CO2 transport
RBC composition
33% Hb and rest is water and lipids, protein, ions
Hemoglobin structure
Globin with 4 chains: beta chain 1 and 2, alpha chain 1 and 2. in each chain, heme group with Fe2+ in it
MW of hemoglobin and count in one RBC
64 K (Molec. weight similar to albumin). 200-300 x 10^6 molecules of Hb in each RBC.
What is heme and occurence in one Hb
molecule of organic pigment : 1 per chain (4 in one Hb)
What heme does and frequency in one Hb
Each heme binds O2 molecule
Hb what it does in lungs and in tissues and how it appears
In lungs, Hb becomes saturated with O2 (appears bright red). In tissues, O2 dissociates from Hb (Hb appears dark red)
Normal solubility of O2 in plasma
0.3 mL O2/100 mL plasma (very low)
Carrying capacity of O2 in blood (because
20 mL/100 mL of blood
Hb functions (3)
1) Transport of O2 2) Transport of CO2 3) Act as a buffer
Hb equilibrium reaction with O2 transport
Hb + O2 —- (eq) —- HbO2
Advantages of having Hb inside the cell rather than dissolved in plasma (3)
1) Plasma viscosity 2) Plasma C.O.P 3) Loss via Kidney
Hemoglobin values in males and females
M: 16g/100 ml blood F: 14g/100 ml blood
When Hb is fully saturated with O2, each g of Hb holds________ of O2
1.34 ml O2 per gram of Hb (note : one Hb molecule is not 1g of Hb )
Estimation of O2 carrying capacity of blood
15g of Hg (per 100 mL of blood) * 1.34 ml of O2 per g of Hb = 20 ml O2 / 100 ml blood
Factors affecting ability of Hb to bind and release O2 (5)
Temperature, Ionic composition, pH, pCO2, Intracellular enzyme concentration
RBC precursors : time length of division and differentiation and where it happens
3-5 days. Bone marrow
Last step of RBC precursor differentiation, duration and where it happens
Reticulocyte -> RBC. 24 hours. In circulation
Initial RBC stem cell size
18 micrometers
3 things that happen to stem cells during erythropoiesis (in order to become RBCs)
- Decrease in size 2. Loss of nucleus 3. Accumulation of Hb
Normal reticulocyte count: how much, what’s the other name for it and what it reflects
<1%. Also reticulocyte index. Reflects amount of effective erythropoiesis in bone marrow
Factors determining number of RBCs (2)
O2 requirements
O2 availability
2 (related) examples of factors that can influence O2 availability
Altitude and pO2
What is erythropoietin
Glycoprotein hormone/cytokine produced largerly by the kidney
What is the stimulus for erythropoietin release and what could possibly cause that
Hypoxia (decreased RBC count, decreased availability of O2 to blood, increased tissue demand for O2)
Erythropoietin abreviation. To what extent is erythropoietin known
EPO has been purified, sequenced, gene has been cloned and EPO has been produced by recombinant DNA technology
Regulation of erythropoiesis
Bone marrow -> low RBC -> low oxygen supply -> low oxygen supply to kidneys -> hypoxia and increase of erythropoietin release -> erythropoietin in plasma -> EPO goes to bone marrow
What erythropoietin does
Stimulates bone marrow to produce more RBCs thereby maintaining homeostasis
cascade of events after a severe accidental hemorrhage
less Hb available for O2 transport -> reduced supply of O2 to kidneys -> increased production and release of EPO –> increased production of erythrocyte precursors in bone marrow –> increased discharge of young erythrocytes in blood –> More Hb for O2 transport (negative feedback loop that downregulates production and release of EPO in kidneys)
EPO inducer or stimulant
Stimulant : Stimulates proliferation of COMMITED STEM CELL (to erythropoeitin)
(Inducer stimulates self-replication and differentiation of pluripotential stem cell)
Erythropoeitin action (2 things it does)
EPO stimulates proliferation of stem cell commited to erythropoiesis and Accelerates maturation of cells leading to Reticulocytes
What hormones can affect EPO quantity (2)
Testosterone -> increases release of EPO (hypoxia) and sensitivity of RBC precursors to EPO.
Estrogen : opposite effect
Why males have higher amount of RBC
more testosterone than females -> higher release of EPO (hypoxia) and sensitivity of RBC precursors to EPO
T/F : RBC life span can be prolonged
F -> nothing prolongs RBC lifespan
What happens to old RBCs
recognized and removed from circulation by system of highly phagocytic cells called macrophages
What happens after phagocytosis of RBC
digestive enzymes of macrophage degrade RBC membrane and its constituents
What happens after digestion of RBC by macrophage
Contents released
Macrophage digestion of RBC things released
From Hb, Heme group, globin, iron.
What happens with globin released from RBC digestion by macrophage
Degraded into a pool of amino acids
What happens with iron released from RBC digestion by macrophage
Sticks to transferrin (iron transport protein in plasma)
Why transferrin necessary for the body
Free iron would be toxic for the body
What transferrin does (2)
1) Iron ions transfered to ferritin that is stored in liver, spleen, gut
2) Transfers iron to the bone marrow
What ferritin does
Releases iron in the bone marrow
What happens to heme group released from RBC digestion by macrophage
Transformed into bilirubin (a brown/yellow pigment)
What gives plasma its colour and what’s its concentration
bilirubin 1 mg/dL
What happens to bilirubin
Goes through liver and and goes through intestinal tract via bile
Why feces are brown
because bilirubin in intestinal tract is transformed in other pigments by the bacteria
why urine is yellow
contains bilirubin
What is jaundice and medical term for it
Yellowing of skin, nails, organs, eyes. Icterus is the medical term
4 possible causes for jaundice
- Excessive hemolysis (RBC destruction)
- Hepatic damage (liver)
- Bile duct obstruction (bilirubin transported from liver to intest tract via bile)
- Dehydration
Other case where jaundice occurs
Neonatal jaundice. In the womb, baby produces more RBC for more oxygen, but this stops after birth
Normal dynamic for RBC
Production = Destruction
Abnormal dynamics for RBC and name of pathology
Production > Destruction –> Polycythemia
Production < Destruction –> Anemia
