Blood Physiology Lecture 1 - RBCs, Basic Facts, Hematopoiesis

Blood components

Plasma, red blood cells, white blood cells, and platelets

Functions of blood (4)

1. Transport of substances
2. Regulation of ion and pH balance
3. Defense and immune protection
4. Hemostasis (prevention of blood loss)

How to separate blood

centrifuge

Layers of blood

Upper layer: plasma (55%)
Middle layer: buffy coat (WBCs and platelets, <1%)
Bottom layer: RBCs (45%)

Hematocrit

percentage of blood volume occupied by red blood cells

Clinical significance of hematocrit

Can indicate low numbers of RBCs (anemias) and high numbers of RBCS (polycythemia)

2 major fluid compartments inside cells

1. Intracellular - fluid inside cells
2. Extracellular - fluid outside cells (includes plasma and interstitial fluid)

Composition of plasma

Liquid portion of blood, contains:
- Water
- Electrolytes
- Organic molecules
- Trace elements
- Gases

4 classes of plasma proteins

albumins, globulins, fibrinogen, transferrin

Site of plasma protein synthesis

liver

Albumin function

contribute to colloid osmotic pressure of plasma, transport substances

Globulin function

clotting factors, enzymes, antibodies, carriers for substances

Fibrinogen function

Fibrinogen threads in blood clotting

Transferrin function

Iron transport

What is Serum?

plasma without clotting factors

Function of serum

distribution, buffering, transport , defense, hemostasis

3 types of blood cells

erythrocytes (RBCs), leukocytes (WBCs), thrombocytes (platelets)

Red blood cell function

transport oxygen and carbon dioxide

White blood cell function

Neutrophils - phagocytes
Eosinophils - Defense against parasites
Basophils - inflammation response
Monocytes - phagocytes and immune defense (transform into macrophages)
Lymphocytes:
- B cells - antibody protection and humoral immunity (bodily fluids0
- T cells - cellular immunity

Hematopoesis

blood cell formation

Prenatal hematopoiesis location

Yolk sac, liver, spleen

Post-natal hematopoiesis location

Bone marrow

Factor regulating hematopoiesis

Cytokines
- Hormone-like and released into blood and act on receptors of target cells
- Ex. Erythropoietin and thrombopoietin

Red blood cell characteristics

- Biconcave shape = higher SA:V ratio
- Lose nucleus and other organelles in development
- Contains lots of hemoglobin for O2 binding
- 120 lifespan

Structure of hemoglobin

Composed of heme and globin
- HbA has 2 alpha globin chains and 2 beta globin chains, 4 heme groups (1 o2 binding per heme)

Function of hemoglobin

In red blood cells, carries oxygen from the lungs to body's tissues and returns carbon dioxide from tissues back to lungs. It also maintains the shape of red blood cells.

Oxygen coopertive binding

1 O2 binding to a heme group influences the other 3 heme groups to have higher affinity

2,3-Bisphosphoglycerate

Binds to hemoglobin, converts to the T state so no O2 can bind

What makes CO inhalation fatal

Carbon monoxide has a 200X higher binding affinity for hemoglobin than O2 does.
- CO is colorless and odorless