Cardiovasvular System 1 Flashcards
What are the functions of blood?
Transportation
- Oxygen, nutrients and hormones directly or indirectly to cells
- Carbon dioxide and metabolic wastes away from cells
Regulation: maintains homeostasis of all body fluid
- regulates body temperature
- absorption of heat
- vasodilation of blood vessels
- regulates pH
- regulates water content of cells
Protection
- Contains immune cells and numeral agents that protect the body from:
- pathogenic agents
- foreign bodies
- transformed Cells
- Blood loss: clotting factors
What are the techniques of blood sampling?
Venipuncture
-sample taken from vein with hypodermic needle and syringe
Finger or heel stick
-Common technique for diabetic to monitor daily blood sugar
-method used for infants
What are the components of blood?
Plasma: 55%
Formed elements : 45%
What is plasma?
A watery liquid extracellular matrix containing proteins and dissolved substances (55% of blood)
91.5% water
- 5% other solutes
- electrolytes, nutrients, gases, regulatory products
7% plasma proteins
-produced in the liver or by circulating blood cells
What are the plasma protein in plasma?
Albumin
- maintains colloid osmotic pressure of in the blood
- transport protein for steroids and fatty acids.
Globulins(immunoglobins)
-antibodies that bind foreign particles eg bacteria
Fibrinogen(fibrin)
-clotting
What are the formed elements in blood?
I. Red blood cells: erythrocytes
II. White blood cells: leukocytes
A. Granular: contains specific granules
- Neutrophils
- Eosinophils
- basophils
B. Agranular: no specific granules -Lymphocytes: T cell B cell Natural killer cells -Monocytes III. Platelets: thrombocytes
Explain hemopoeisis(hematopoeisis)
Formation of blood cells
Includes: erythropoiesis, leukopoeisis and thrombopoeisis
Maintains a constant level of different cell types found in the peripheral blood
-erythrocytes, granulocytes, monocytes, thrombocytes and B lymphocytes are formed and mature in red bone marrow
T lymphocytes are formed in red bone marrow and mature thymus
Regulated by growth factors: erythropoetin, cytokines and thrombopoietin
Explain hematopoietic organ function
Yolk- sac phase- formation of blood islands in the 3rd week of gestation (lasts for 3-8 weeks)
Hepatic phase- main hemopoietic organ in second trimester
Bone marrow phase-begins during second trimester. (Also includes other lymphatic tissues eg spleen)
After birth: hemopoiesis takes place only in the bone marrow
NB: in diseases states where the bone marrow becomes non functional, spleen and liver can produce blood cells
Describe erythrocytes
Biconcave discs with a diameter of 7-8 um
- lacks a nucleus and other organelles (Anaerobic)
- contain the oxygen-carrying protein hemoglobin, which is the pigment that gives blood it’s really color
What is the life span of erythrocytes?
120 days
What is significant about the antigens on plasma membrane of RBCs?
They account for the ABO and Rh blood group systems
What are the functions of hemoglobin?
Consists of the globin protein which has four polypeptide chains (two alpha and two beta)
- Each chain is bound to a ring-like non pigment called Heme
- Each heme molecule has an iron (Fe2+) that binds reversibly with oxygen
- Therefore each molecule of hemoglobin binds four molecules of oxygen and delivers it to the tissues
- Binds with O2 from tissues and transports it to the lungs where it is exhaled
What is a hematocrit?
Percentage of total blood volume occupied by red blood cells
- female normal range
- 38%-46% (average of 42%)
- male normal range
- 40% -54% (average of 46% )
- testosterone
What is anemia?
Not enough RBCs or not enough hemoglobin
What is polycythemia?
- too many RBCs (over 65%)
- dehydration, tissue hypoxia, blood doping in athletes
What is erythropoiesis?
The main stimulus for erythropoiesis is hypoxia
Rate of erythropoiesis is measured by a reticulocyte count
Explain the process of erythropoiesis
- Some stimulus disrupts homeostasis
- Oxygen delivery to kidneys (and other tissues) is decreased
- Kidney cells detect low oxygen level. Increased erythropoietin secreted into blood
- Control center- proerythroblasts in red bone marrow mature more quickly into reticulocytes. More reticulocytes enter circulating blood
- Larger number of RBCs in circulation. This leads to increased oxygen delivery to tissues
- Return to homeostasis when oxygen delivery to kidneys increases to normal
Explain ABO blood groups
Based on 2 isoantigens called A and B found on the surface of RBCs
-display only antigen — blood type A
- display only antigen — blood type B
- display both antigens A and B — blood type AB
-display neither antigen — Blood type O Plasma contains isoantibodies to the A or B antigens not found in your blood - anti-A antibody reacts with antigen A - anti-B antibody reacts with antigen B
Give the specifics of Blood type A
Surface antigen: A
Serum antibody : anti-B
Can donate to: A and AB
Can receive from: A and O
Give the specifics of blood type B
Surface antigen: B
Serum antibody: anti-B
Can donate to: B and AB
Can receive from : B & O
Give the specifics of blood type AB
Surface antigen A and B
Serum antibody : none
Can donate to only AB
Can accept any type
Give the specifics of blood type O
No Surface antigen
Serum antibody: anti A and anti B
Can donate to any type
Can. Only accept from O
Give a background of Rh blood groups
Antigen was discovered in blood of Rgesus monkey
- People with Rh antigens on RBC surface are Rh+
- Normal plasma contains no anti-Rh antibodies
Explain Rh group transfusion
Antibodies develop only in Rh- blood type and only with exposure to the antigen
-transfusion of positive blood
- during a pregnancy with a positive blood type fetus
Transfusion reaction upon 2nd exposure to the antigen results in hemolysis of the RBCs in the donated blood
