Blood Physiology (Exam 1) Flashcards
What does blood do?
- Transportatiton - gases, nutrients, and wastes
- Regulation - pH, temperature, and water levels
- Protection - clotting, immunity, and phagocytosis
What is phagocytosis?
When phagocytes essentially devour foreign bacteria.
What is the average temperature of blood?
100.4 degrees F
compare that to normal body temp of 98.6 degrees F
(blood helps store heat)
Average pH of blood
7.35-7.45
(slightly more basic than acidic)
What volume of blood is contained within Males and Females on average?
Males - 5-6L
Females - 4-5L
Viscosity of blood
More viscous than water.
(Blood is thicker than water)
What color is blood?
Red (oxygenated)
What component makes up the majority of Blood Plasma?
Water (91.5%)
What are the component of Blood?
- Plasma
- Formed elements
What is plasma?
a non-living fluid matrix
What are the formed elements?
- Leukocytes
- Erythrocytes
- Thrombocytes
LET
What are the 5 types of Leukocytes?
- Neutrophils
- Lymphocytes
- Eosinophils
- Monocytes
- Basophils
NLEMB
Normal Percentage of Neutrophils in WBC count and function?
- 60-70%
- phagocytosis of bacteria; defensins
What is a defensin?
a peptide in WBCs that plays a role in the prevention or elimination of infection
Normal Percentage of Lymphocytes in WBC count and function?
- 20-25% (2nd most common)
- B-cells
- antibody secretion, attack bacteria
- T-cells
- attack viruses, fungi, cancer cells, transplanted cells
- NK cells - Type of T-cell - nonspecific defense
- attack viruses, fungi, cancer cells, transplanted cells
What are the two (technically 3) types of Lymphocytes and what is their function?
- B-cells
- antibody secretion, attack bacteria
- T-cells
- attack viruses, fungi, cancer cells, transplanted cells
- NK cells - nonspecific defense
- attack viruses, fungi, cancer cells, transplanted cells
Normal Percentage of Monocytes in WBC count and function?
- 3-8%
- phagocytosis as macrophages
- emigrates - leaves bloodstream -becomes macrophage
Normal Percentage of Eosinophils in WBC count and function?
- 2-4%
- phagocytize antigen-antibody complexes, antihistamine
- increased prevalance when parasitic worms are present
Normal Percentage of Basophils in WBC count and function?
- 0.5-1%
- intensifies inflammatory response
Info nugget: Differential WBC Count
- If a particular Leukocyte percentage varies from normal, it impacts the percentage of the other Leukocyte types.
- Differential Leukocyte percentages allow identification of infection, allergic reactions, blood disorders, etc.
Info nugget: Leukemia
- Diagnosis of Leukemia stems from an elevated leukocyte count
- The higher number of leukocytes are less functional than normal and causes underproduction of Erythrocytes and Thrombocytes
- Decreased Eryhtrocytes = anemia
- Decreased Thrombocytes = clotting issues
What percentage of blood plasma is protein?
7%
What are the 3 blood plasma proteins, their normal percentage and their function?
- Albumin (54%) - transport
- Globulins (38%) - antibodies
- Fibrinogen (7%) - main clotting protein
Normal platelet count per µL
150k-400k per µL
Normal WBC count per µL
5k-10k per µL
Normal RBC count per µL
4.8MM-5.4MM per µL
What is Hemopoiesis?
The generation of blood cells
- Blood cells in general, not a specific type
Where does Hemopoiesis start?
Red bone marrow
What is the hierarchy of cells in hemopoiesis from early-stage to late-stage cells?
- Pluripotent stem cells (develop into several different types
- Myeloid and lymphoid stem cells
- Progenitor cells (from some myeloids)
- “Blasts” - precursors to specific types
- eg. eosinophilic myeloblast becomes eosinophil
P(ML)PB
What is Erythropoiesis?
the creation of red blood cells
What is the hierarchy of cells in erythropoiesis from early-stage to late-stage?
- Pluripotent stem cell
- Myeloid stem cell
- Colony Forming Unit - Erythrocyte (CFU-E)
- Proerythroblast
- Reticulocyte (nucleus is ejected into bloodstream)
- Erythrocyte matures in 1-2 days then enters bloodstream
PMCPRE
What triggers erythropoiesis?
- Erythropoietin is produced by the kidneys which stimulates erythropoiesis
- Hypoxia triggers kidneys to release EPO
Describe the Negative Feedback cycle of Erythropoiesis
- Hypoxia triggers the kidneys to release erythropoietin (EPO)
- EPO causes proerythroblasts to mature more rapidly
- This leads to more RBCs, which means greater oxygen-carrying capacity to tissues (including kidneys)
- Kidneys detect stable oxygen-carrying capacity and halts the release of EPO
What is Hemoglobin and what are its componenets?
- a protein that transports oxygen in the blood.
- Globin - protein composed of four chains
- Heme - Fe2+ at center binds to O2
- One Heme per chain = 4 O2 per molecule
- B12 also needed
How many Hemoglobin molecules per RBC?
280 million molecules per RBC
What is anemia?
a reduced oxygen-carrying capacity
What are the types of anemia?
- Hemorrhagic anemia - blood loss
- Aplastic anemia - marrow doesn’t produce RBCs
- Thalassemia - inherited - fewer RBC and hemoglobin
- Hemolytic anemia - RBC destruction
- Iron-deficient anemia - most common
- Megaloblastic anemia - larger RBCs
- Pernicious anemia - cannot absorb B12 (type of megalobalstic)
- Sickle-cell disease - malformed hemoglobin/RBCs
HATH IMPS
What is Hemorrhagic anemia?
type of anemia characterized as blood loss
What is aplastic anemia?
type of anemia characterized by marrow not producing RBCs
What is Thalassemia?
type of anemia that is inherited where there are fewer RBCs and hemoglobin
What is Hemolytic anemia?
anemia characterized by RBC destruction
What is iron deficient anemia?
- anemia characterized by iron deficiency
- most common
What is megaloblastic anemia?
anemia characterized by larger RBCs
What is pernicious anemia?
- anemia characterized by inability to absorb B12
- type of megaloblastic anemia
What is sickle cell anemia?
anemia characterized by malformed hemoglobin/RBCs
What is the ife cycle of erythrocytes?
120 days
Describe the RBC destruction process
- Macrophages in spleen, liver and red marrow target old/damaged RBCs
- Heme breakdown occurs
- Fe3+ attaches to transferrin - can be transported back to red marrow
- Fe3+ can detach and be stored by ferritin in some locations (liver, muscle)
- Non-iron portion > biliverdin > bilirubin
- non-iron portion is excreted
- Bilirubin transported to liver, released into bile, passed to intestine > urobilinogen > stercobilin (poo)
- Jaundice
What is the general function of leukocytes?
- Phagocytosis
- Immune Response
- Emigration (Diapedesis)
- leaves blood cells to go to other tissues
PIE
What is chemotaxis?
movement toward a chemical stimulus
From what stem cells do leukocytes originate?
With the exception of lymphocytes, myeloid stem cells are where leukocytes originate from
- Myeloid stem cells
- lymphocytes originate from lymphoid stem cells
How do B and T cells develop?
- Begin as pluripotent stem cells
- become lymphoid stem cell
- finish development in lymphatic tissues to become either B or T cell
What is the role of cytokines (CSFs and interleukins)?
Trigger the development of leukocytes
What are the two types of neutrophils?
band and segmented
total of 60-70%
What is an NK Cell?
Natural Killer Cell
What do T-Cells do?
they go after virus-infected cells and destroy the entire cell
Thrombocytes: Cell Hiearchy from inception to maturity, count per µL, and functions (2)
- Thrombopoeietin causes myeloid stem cells > megakaryoblasts > megakaryocytes > splinter into platelets (thrombocytes)
- 150,000-400,000 per uL
- Form plugs in damaged vessels
- Release clotting factors
Hemostasis: Definition and what are its mechanisms (3)?
- Sequence of responses that stops bleeding (possible hemorrhage)
Mechanisms:
- Vascular spasm
- Platelet plug formation
- Blood clotting (Coagulation)
Vascular spasm: What is it and what does it do?
- Immediate contraction of smooth muscle in arteries and arterioles
- Reduces blood loss - allows time for other mechanisms to start
*** review diagrams
Platelet Plug Formation process
- Vessel breaks, exposing collagen fibers of the wall to blood
- In presence of rough surfaces such as collagen, platelets adhere to vessel and other platelets
- Platelets aggregate and release factors that promote hemostasis
- hemostasis factors: Adenosine diphosphate (ADP), serotonin, and thromboxane A2
- this causes the platelet plug and leads in to clotting
Clotting (Coagulation): Components, definition, and deficiencies
- Serum = blood plasma w/out clotting proteins
- Clot = gel formed from formed elements trapped in fibrin
- fibrin is most important in clots
- clots are not just platelets
- Cascade of reactions involving sequence of clotting factors (Ca2+, enzymes from liver, vitamin K derivatives)
- Thrombosis - inappropriate clot
- Hemorrhage - excessive bleeding
- Hemophilia - inability to clot - why?
-ase suffix means?
enzyme
Clotting Stages (Common Pathway)
- Prothrombinase formation
* Common Pathway = steps after prothombinase formation - Prothrombinase converts prothrombin into thrombin
- Thrombin converts soluble fibrinogen into insoluble fibrin
Extrinsic vs Intrinsic pathways
- Extrinsic has fewer steps, occurs rapidly, and cue comes from outside vessels (Tissue factor (TF))
- TF leaks in from outside, begins extrinsic pathway
- Intrinsic more complex, slower, and activators are in vessels or within blood
- Common pathway = steps after prothrombinase formation
- Clot retraction
Hemostatic Control Mechanisms: What are they (2)/name them
- Fibrinolysis - dissolution of a clot (either after repair or inappropriate clots)
- Degraded by plasminogen > plasmin
- Fibrinolysis is the natural way of dealing with clots
- Anticoagulants - antithrombin, heparin, warfarin (Coumadin)
Intravascular clots can still form due to rough endothelium or blood stasis
- Thrombus (unbroken vessel)
- Embolus - mass or air bubble transported by bloodstream
-lys- root word means?
to break down/dissolve
Complete blood count: What cells/factors are measured when considering a complete blood count?
Counts of:
- RBCs per uL
- WBCs per uL
- Platelets per uL
-
Hematocrit (RBC % of total blood volume)
- anemia test
- Differential WBC
- Hemoglobin (g/mL)
Stem cell transplants: Types/definitions, which one is more advantageous?
- Bone marrow transplant - destruction of defective marrow and replacement
- Cord-blood transplant advantages:
- Easily collected and stored (at birth from ubilical cord)
- More abundant stem cells than in marrow
- Less likely to cause graft-versus-host disease or to transmit infections
Hemolytic Diseases of the Newborn (HDN): What is it?
- Rh Incompatibility
- Possible agglutination and hemolysis
- RhoGAM given to Rh- women (inactivates fetal Rh+ antigens)