CARDIOVASCULAR SYSTEM
BLOOD
HEMATOLOGY - branch of science concerned with the study of blood, blood-forming tissues, and the disorders associated with them.
Blood sample collection: a. Venipuncture
b. Fingerstick or Heelstick
c. Arterial Blood (Arterial Blood Gas)
I. Functions of blood
1. Transportation: a. O2 and CO2
b. nutrients, heat, waste products
c. hormones
2. Regulation: a. blood pH through buffers
b. body temperature
c. blood osmotic pressure
3. Protection: a. clotting system
b. WBC
c. antibodies
II. Physical characteristics and Volume
a. Opaque with metallic taste
b. Color varies from scralet (02 rich) to dull red (02 poor)
c. Heavier in water and 5x thicker
d. Slightly alkaline: pH 7.35 - 7.45
e. Temperature is slightly higher than body temperature.
f. Accounts for 8 % of TBW
g. 4 - 5 L. in females; 5 - 6 L. in males
III. Composition
1. Plasma
a. 55 % of the whole blood
b. liquid part of the plasma which is 91.5% water and 8.5% solutes (7% of it are proteins)
c. straw colored fluid
d. most abundant solutes in the plasma are PLASMA PROTEINS
e. Proteins in the plasma are:
Albumin: smallest and most numerous plasma proteins
- Function as transport proteins for several steroid hormones and fatty acids.
Globulins - protein group to which Ab (immunoglobulins) belong
- produced by liver and plasma cells which develop from B lymphocytes
- Alpha and Beta Globulins transport iron, lipids, and fat soluble vitamins
- Gamma Globulins: Immunoglobulins
Fibrinogen - role in blood clotting
f. Contains other solutes such as electrolytes, nutrients, gases, regulatroy substances, and wastes
2. Formed Elements: blood cells and cell fragments
- 45 % of the whole blood
- 99 % are RBC; 1 % are WBCs and Platelets
- BUFFY COAT - layer which contains the WBCs and platelets
a. Red Blood Cells/ Erythrocytes
- Contains the O2 carrying protein HEMOGLOBIN which is a pigment giving blood its red color.
- Males: 5.4 million/mm3; Females: 4.8 million/mm3
- Anucleated; biconcave discs - plasma membrane is strong and flexible
- No mitochondria
- Life cycle: 120 days
ERYTHROPOIESIS - production of RBC
ERYTHROPOIETIN - stimulates production of RBC
HEMATOCRIT - percentage of the total blood volume occupied by RBCs
Normal range: Females = 38 - 46%; Males = 40 - 54%
- Testosterone stimulates synthesis of erythropoietin in males.
- Transports Nitric Oxide which helps regulate BP.
CLIN.CORR: ANEMIA
POLYCYTHEMIA
** RBC Life Cycle:
b. White Blood Cells/ Leukocytes
- Nucleated; no hemoglobin
1. Granular Leukocytes:
Neutrophils
Basophils
Eosinophils
2. Agranular Leukocytes:
Lymphocytes
Monocytes
c. Platelets/ Thrombocytes
- 150, 000 - 400, 000/ mm3
- 2 - 4 μm in diameter; Cell fragments live for 5 - 9 days
- Contain many vesicles but no nucleus
- Form platelet plug in hemostasis; release chemicals that promote vascular spasm and blood clotting.
- Aged and dead platelets are removed by fixed macrophages in the spleen and liver.
HEMOSTASIS
- Sequence of responses that stops bleeding
- When blood vessels are damaged or ruptured, the hemostatic response must be quick and localized to the region of damage and carefully controlled.
3 Mechanisms:
1. Vascular Spasm
2. Platelet Plug Formation
a. Platelet Adhesion
b. Platelet Release Reaction
c. Platelet Aggregation
3. Blood Clotting
CLOT RETRACTION
- Consolidation or tightening of the fibrin clot.
- Fibrin threads attach to the damaged surfaces and gradually contract as the platelets pull on them.
- As the clot retracts, it pulls the edges of the damaged vessels together, decreasing the the risk of further damage.
SERUM -
ROLE OF VITAMIN K
- Required for the synthesis of Factor II, VII, IX, and X.
- Normally produced by a bacteria in the large intestine.
ABO and Rh Blood Groups
AGGLUTINOGENS/ ISOANTIGENS - antigens found on the surface of the RBC.
HEMOLYTIC DISEASE OF THE NEWBORN (ERYTHROBLASTOSIS FETALIS)
Page Updated: Sun Jan 21 2007 20:03:08 GMT+0800
