NOVA- Anesthesia Physiology Exam 2

RBCs (erythrocytes)

Transport of O2 and CO2

-lacks nucleus

Platelets (thrombocytes)

Hemostasis through blood clotting

WBCs (leukocytes)

Defense

Hematopoiesis

-blood cell formation

-occurs in bone marrow

-in neonates, most of skeleton is active bone marrow

-in adults, mainly in vertebrae, ribs, skull, pelvis, and proximal femur

-derived from stem cells

Common myeloid progenitor and common lymphoid progenitors

Hematopoietic stem cells differentiate into what?

Thrombopoietin (TPO)

Common myeloid progenitors differentiate into megakaryoblasts with the help of which hormone?

-regulates rate of platelet formation

-secreted by liver and kidneys

Erythropoietin (EPO)

Common myeloid progenitors differentiate into proerythroblasts with the help of which hormone?

-primary regulatory hormone

-released from kidneys when O2 tension is reduced

Megakaryoblasts, proerythroblasts, myeloblasts, and monoblasts (all eventually mature into -cytes)

Common myeloid progenitors differentiate into what 4 types of blasts?

Megakaryocyte

Megakaryoblast turns into?

Erythrocytes

Proerythroblast turns into?

Granulocytes: Eosinophil, basophil, and neutrophil

Myeloblasts differentiate into?

Monocyte (agranulocyte)

Monoblast turns into?

Lymphocyte (agranulocyte)

Lymphoblast turns into?

Erythropoiesis

Red blood cell formation

-replaces 0.8-1.0% of circulating RBCs daily

-regulated to provide adequate O2 to tissues

-requires Iron, Folic acid, and Vit B12

-produces Hb

-cell organelles disappear

Thrombopoiesis

Platelet production

-platelets have NO nucleus

-platelets are disk shaped

Leukopoiesis

WBC production

-T lymphocytes- thymus

-B lymphocytes- bone and lymph

Reticulocyte

Immature RBC

-if elevated, this means your body has increased its demand of RBCs

-useful index for RBC production

Number of platelets in circulation

Plasma concentration of TPO (thrombopoietin) is determined by what?

LOW platelet count (thrombocytopenia)

High TPO (thrombopoietin) is a result of what?

Monocytes

-agranulocyte

-leaves bone marrow as soon as its formed

-spends 2-3 days in circulation before becoming macrophages

Pliable; microcirculation

RBCs are ____ and allow passage through _______

LARGE osmotic pressures

RBCs can withstand ________, when they pass through renal medullary circulation

Hb, Glycolytic enzymes, and Carbonic Anhydrase

When RBCs leave the bone marrow, they contain what key cytoplasmic proteins?

Carbonic anhydrase

Essential for CO2 carriage in the blood

-carried by RBCs when they leave the bone marrow

Glycolyitic enzymes

No mitochondria, MUST GET ATP VIA GLYCOLYSIS

-carried by RBCs when they leave the bone marrow

Hemoglobin

Large O2 carrying capacity of blood

-carried by RBCs when they leave the bone marrow

100-120 days

Normal lifespan of a RBC?

Macrophages

Aging RBCs are removed by ______, mainly in the spleen

Bilirubin

End product of Hb breakdown is ______, which is conjugated in the liver and excreted in the bile

Anemia

Red cell mass decreased

Polycythemia

Red cell mass increased

Hb concentration

Hb per volume of blood

HCT/ packed cell volume

Ratio of red cells to volume of whole blood

RBC count

Number of RBC per liter of blood

Mean cell volume (MCV)

Average size of RBC

Femtoliters

Measures MCV, average volume of single red cells expressed

HCT/ RBC count

How to calculate MCV

Microlytic

<80 fL --> small

-MCV

Macrolytic

>100 fL --> large

-MCV

Mean cell hemoglobin (MCH)

Average amount of Hb in red cell

Hb/ RBC count

Mean cell hemoglobin concentration (MCHC)

Average concentration of Hb in RBC

MCH/MCV

Blood smear

Performed to look at size and shape of cells

-e.g. a reticulocyte count is determined in patients with anemia to assess rate of red cell production

So our body recognizes them as self

Why are our RBCs tagged with antigens?

Antigens (agglutinogen)

Found on the surface of cells to help immune system recognize self cells

Antibodies (agglutinins)

Secreted by lymphocytes in response to foreign cells (in plasma)

Type A

Has the A antigen

Type B

Has the B antigen

Type AB

Has BOTH A and B antigens

Type O

-can be given as universal donor because there are no antigens on O

Has NEITHER A nor B antigens

Anti- B antibodies

Type A blood has what kind of antibodies?

Anti- A antibodies

Type B blood has what kind of antibodies?

NO antibodies (universal recipient)

-the immune system would attack if there were any antibodies

Type AB blood has what kind of antibodies?

Anti A and anti B antibodies (universal donor)

Type O blood has what kind of antibodies?

Antibodies would bind to erythrocytes and cause agglutination and hemolysis

What would happen if a person received the wrong blood type?

Rh factor

Antigen D

Rh-positive

Has antigen D

Rh- negative

Does not have the D antigen

-Rh- mother that carries an Rh+ fetus will develop Anti-Rh antibodies

-first pregnancy is viable

-issue arises when second pregnancy involves another Rh+ fetus

-that fetus will be attacked by Anti-Rh antibodies produced by the mother in pregnancy number one

Describe Rh factor issues in pregnancy

RhoGAM

Inactivates the Anti-Rh antibodies (Anti-D ABs) made against Rh+ fetuses

Hemostasis

Regulated interactions between blood vessel walls, circulating platelets, and clotting proteins in plasma

Fibrinolysis

Once a stable clot is formed, it is removed via _______

Vasoconstriction

What is the first occurrence after a cut that allows for less volume in the area as well as less blood loss?

Serotonin and thromboxane A2

Platelet activation and clot formation at the site of injury results in the release of what two vasoconstrictors?

Thrombin

-clotting protein

-highly potent endothelin-1

Platelet plug formation

Primary hemostasis

-occurs at site of damage

-FAST

-BIGGEST AFFECT ON ARTERIES

Clot formation

Secondary hemostasis

-fibrin mesh forms with platelets and other trapped cells

-SLOW

-BIGGEST AFFECT ON VEINS

POSITIVE feedback loop

Platelet function is a ______

Platelet Adhesion

-phase 1

-encompasses Integrin family, vWF, Thromboxane A2, and Thrombin

Integrin family

Binds to extracellular matrix proteins (collagen) in Phase 1 Platelet Adhesion

von Willebrand factor (VWF)

Released by endothelial cells and activated by platelets

-promotes platelet adhesion by promoting cross links between platelets and collagen

-acts in Phase I Platelet Adhesion

-augments platelet adhesion and aggregation in Phase 2 Platelet Activation

Platelet Activation

-phase 2

-release of many factors that promote hemostasis (ADP, Serotonin and Thromboxane A2, vWF, Ca2+, Fibrinogen, Factor V, and Platelet-derived growth factor (PDGF))

ADP

What amplifies platelet activation response in Phase 2- Platelet Activation?

Ca2+, Fibrinogen, and Factor V

What facilitate coagulation in Phase 2 Platelet Activation?

Platelet- derived growth factor (PDGF)

What promotes wound healing through fibroblasts in Phase 2 Platelet Activation?

Platelet Aggregation

-phase 3

-completes formation of the platelet plug

Prostacyclin and nitric oxide

Platelet plug is prevented from extending beyond site of injury by ______ which are secreted by intact endothelial cells and INHIBIT PLATELET ACTIVATION

-occurs in Phase 3 Platelet Aggregation

Fibrinogen; Fibrin

Blood clot is formed when ______ is proteolytically cleaved to form ______

Platelet Activation (phase 2)

Clots can occur without ______, but there is usually parallel activation of primary and secondary hemostasis

Intrinsic and extrinsic pathways

How can clotting be initiated?

Cascade

Intrinsic and extrinsic pathways are both a _____ that turns inactive proteins (clotting factors) into active form

LOW

Clotting factors are normally ____ in circulation to prevent the clotting cascades from becoming active

Intrinsic pathway

-clotting cascade

-triggered when blood contacts a negatively charged surface (exposed subendothelial collagen, aggregation of platelets, etc.)

-thought to be most important pathway for maintaining thrombin generation

Extrinsic pathway

-clotting cascade

-activated when blood contacts cells outside the vascular endothelium

-thought to be the most important pathway for initiating thrombin activation

Tissue factor

Nonvascular cells express _____ which initiates the extrinsic pathway

Common pathway

Final coagulation pathway activated either by the intrinsic or the extrinsic pathway, and ending in the formation of a blood clot

Factor X

The common pathway begins with the activation of ________

-Prothrombin ---> Thrombin

Bleeding time

-sensitive test of platelet function

-small incision made on forearm, and record time it takes to stop bleeding

-ASA increases ______

Prothrombin time (PT)

-evaluates extrinsic coagulation pathway

-sample of blood plasma is incubated with tissue factor with excess Ca2+

Warfarin (anti-coagulant)

What increases prothrombin time?

Partial thromboplastin time (PTT)

-evaluates intrinsic pathway

-adds activator surface (silica) plus phospholipid and Ca2+ to sample

Heparin (anti-coagulant)

What increases PTT?

Capillary endothelium

What is the main source of anticoagulant factors?

Tissue factor pathway inhibitor (TFPI)

What blocks activated Favtor VII in the extrinsic pathway?

-acts as an anticoagulant

Antithrombin III

What binds to activated factor X and thrombin

-acts as an anticoagulant

-is augmented by Heparin

Protein C and S

-anticoagulants

-act together to inactivate activated Factor V and VIII

Plasminogen

Serum protein absorbed into clot

Plasmin

Breaks down fibrin and fibrinogen

-breakdown products are scavenged by macrophages

-NOT ACTIVE IN CIRCULATION

Tissue plasminogen activator and Urokinase-type plasminogen activator

Plasminogen activation is regulated by what two factors released by endothelial cells?

a2-antiplasmin

Free Plasmin is bound to what to prevent clot breakdown?

Heart

What pressurizes blood and provides the driving force?