Chapter 15 - Blood

What is the composition of blood?

RBC, WBC, and plasma

What percent of plasma is proteins?

8%

What is the most abundant protein?

Albumin at 60%

What does albumin contribute to?

Plasma osmotic pressure and plasma volume

What percent of water does plasma have?

90%

What is osmolarity?

Relationship between amount of solutes and water in the blood

What is the normal plasma osmolarity?

300 mOsm

What happens to the osmolarity and blood volume when dehydrated?

Increased plasma osmolarity and decreased blood volume

With dehydration what kind of receptors are activated?

osmoreceptors in the hypothalamus

What is the 2 mechanisms that are triggered when dehydrated?

Drinking water which increases water intake and water retention

ADH secretion into the blood stream and acts on the collecting system of the kidneys and DCT which stimulates the installation of aquaporins then water is reabsorbed from filtrate then water moves into blood stream

What is result of the 2 mechanisms to fix dehydration?

Decreased plasma osmolarity and increased blood volume

What are the characteristics of RBC?

Carries oxygen and carbon dioxide, lacks nuclei and mitochondria, and contain carbonic anhydrase

What does carbonic anhydrase do?

Converts carbon dioxide and water to carbonic acid which is a critical reaction for acid-base (pH) balance

What is erythropoiesis?

Creation of red blood cells

Where are RBC synthesized?

In red bone marrow and is stimulated by erythropoietin

What is erythropoietin released by?

Kidney

What is hemostasis?

Ability to stop blood lose

What are the 4 main steps in hemostasis?

Vascular response/spasm, platelet response, clotting response/coagulation, and clot removal reponse

What happens during vascular response/spasm (step 1 in hemostasis)?

Damage of the blood vessel which causes release of endothelin 1 and then causes vasoconstriction in order to decrease blood flow and minimize blood lose

What happens during platelet response (step 2 in hemostasis)?

This has 3 steps

platelet adhesion: platelets bind to Von Willebrand factor, which is released by endothelial cells which binds to collagen

platelet activation: thrombin binds to platelets -> platelet activation: secretion -> recruitment of more platelets (positive feedback)

platelet aggregation: fibrinogen forms bridges among platelets -> platelet plug/platelet aggregation

What happens during clotting response/coagulation (step 3 in hemostasis)?

The formation of blood clot, which makes thrombin activates fibrinogen and factor 13

which activates fibrin (loose) and factor 13 activated fibrin (stabilized)

What happens during clot removal/fibrinolysis (step 4 in hemostasis)?

This has 4 steps:

clot recognition: blood clot incorporates plasminogen

activation: plasminogen converted into plasmin by tissue plasminogen activators

dissolution: plasmin cut fibrin into fibrin degradation products (FDPs)

clearance: removes the clot, which causes bleeding

What are the 2 pathways for clotting response/coagulation?

Intrinsic and extrinsic, which when either reach factor 10 it becomes the common pathway

Which factors make up the intrinsic pathway?

Factor 12, 11, 9 needs 8 → 10 (common pathway)

What factors make up the extrinsic pathway?

Factor 3 and 7 → 10 (common pathway)

What is the common pathway?

Factor 10 needs 5 and 4 which activate 2 → activate 13 and 1 (fibrinogen) activates fibrin and 2 (thrombin) activates it to become stabilized fibrin

What are the blood types?

A, B, AB, and O

For Type A, what antigen and what antibodies does it have?

Antigen A & Anti-B antibodies

For Type B, what antigen and what antibodies does it have?

Antigen B & Anti-A antibodies

For Type AB, what antigen and what antibodies does it have?

Antigen A and B & No antibodies

For Type O, what antigen and what antibodies does it have?

No Antigen & Anti-A and Anti-B antibodies

How is the positive and negative of each blood type determined?

Depending on presence or absence of Antigen D which is the Rh factor

What is agglutination?

clumping and hemolysis (destruction of RBC)

What causes agglutination for each blood type?

Opposing antibodies ex) Type B receiving Anti-b antibodies

Which blood type is considered the universal RECIPIENT?

Type AB+

Which blood type is considered the universal DONOR?

Type 0-

Which blood type is considered the universal plasma DONOR?

Type AB- or Type AB+

What happens to a Rh+ fetus when it has an Rh- mother?

The mother will be exposed to the Rh+ fetal blood, which produces antibodies and causes erythroblastosis fetalis in future pregnancies