Ch 19 - CV System - The Blood Flashcards
1
Q
blood
A
a liquid connective tissue that consists of cells surrounded by a liquid extracellular matrix (plasma)
2
Q
Functions of Blood
A
- transportats oxygen, carbon dioxide, nutrients, hormones, heat, and waste products
- regulates homeostasis of all body fluids, pH, body temperature and water content of cells
- protects against excessive loss by clotting and against infections through the use of white blood cells
3
Q
Components of Blood
A
- Erythrocytes (RBCs) - 45% (a percentage known as hematocrit)
- Buffy coat - less than 1% - contains leukocytes and platelets
- Plasma - 55%
4
Q
Physical Characteristics of Blood
A
- Oxygen-rich blood is scarlet red
- Oxygen-poor blood is dull red
- pH must remain between 7.35 and 7.45
- Blood temperature is slightly higher than body temperature, at 100.4°F
- In a healthy man, blood volume is about 5–6 liters, or about 6 quarts
- Blood makes up 8 percent of body weight
5
Q
Blood Plasma
A
- Composed of approximately 90 percent water
- Includes many dissolved substances
- Nutrients
- Salts (electrolytes)
- Respiratory gases
- Hormones
- Plasma proteins
- Waste products
6
Q
Plasma Proteins
A
- Most abundant solutes in plasma
- Most plasma proteins are made by liver
- Various plasma proteins include
- Albumin—regulates osmotic pressure
- Clotting proteins—help to stem blood loss when a blood vessel is injured
- Antibodies—help protect the body from pathogens
7
Q
Acidosis
A
blood pH becomes too acidic
8
Q
Alkalosis
A
blood pH becomes too basic
9
Q
Hematocrit
A
the percentage of total blood volume occupied by RBCs
Females: 38-46%
Males: 40-50%
10
Q
Polycythemia
A
- Disorder resulting from excessive or abnormal increase of RBCs
- May be caused by bone marrow cancer (polycythemia vera)
- May be a response to life at higher altitudes (secondary polycythemia)
- Increase in RBCs slows blood flow and increases blood viscosity
11
Q
Hemopoiesis
A
the process of producing blood cells
12
Q
Hemoglobin
A
- Iron-containing protein
- Binds strongly, but reversibly, to oxygen
- Each hemoglobin molecule has four oxygen binding sites
- Each erythrocyte has 250 million hemoglobin molecules
- Normal blood contains 12–18 g of hemoglobin per 100 mL of blood
13
Q
Erythropoiesis
A
- production of red blood cells
- begins in the red bone marrow
- Reticulocytes (immature red blood cells) enter the circulation and mature in 1 to 2 days
14
Q
Erythropoietin
A
a hormone released by the kidneys in response to hypoxia (lowered oxygen concentration) stimulates differentiation of hematopoietic stem cells into erythrocytes
15
Q
White Blood Cells
(Leukocytes)
A
- Crucial in body’s defense against disease
- Complete cells, with nucleus and organelles
- Classified as either granular (containing vesicles that appear when the cells are stained) or agranular(containing no granules)
- Granular leukocytes: neutrophils, eosinophils, basophils
- Agranular leukocytes: lymphocytes, monocytes
- Able to move into and out of blood vessels (diapedesis)
- Move by amoeboid motion
- Respond to chemicals released by damaged tissues (known as positive chemotaxis)
- 4,800 to 10,800 WBCs per cubic millimeter of blood
- May live for several months or years
16
Q
Emigration
A
- During an invasion, many white blood cells are able to leave the bloodstream and collect at sites of invasion. The process is called emigration (diapedesis)
22
Q
Neutrophils
A
- Cytoplasm stains pale pink and contains fine granules
- Deep purple nucleus contains three to seven lobes
- Function as phagocytes at active sites of infection
- Numbers increase during infection
- 3,000–7,000 neutrophils in a cubic millimeter of blood (40–70 percent of WBCs)
23
Q
Eosinophils
A
- Red, coarse cytoplasmic granules
- Figure-8 or bilobed nucleus stains blue-red
- Function to kill parasitic worms and play a role in allergy attacks
- 100–400 eosinophils in a cubic millimeter of blood (1–4 percent of WBCs)
24
Q
Basophils
A
- Sparse but large blue-purple granules
- U- or S-shaped nucleus stains dark blue
- Release histamine (vasodilator) at sites of inflammation
- Contain heparin (anticoagulant)
- 20–50 basophils in a cubic millimeter of blood
(0–1 percent of WBCs)
25
Q
Lymphocytes
A
- Cytoplasm is pale blue
- Dark purple-blue nucleus
- Functions as part of the immune response
- B lymphocytes produce antibodies
- T lymphocytes are involved in graft rejection, fighting tumors and viruses
- 1,500–3,000 lymphocytes in a cubic millimeter of blood (20–45 percent of WBCs)
26
Q
Monocytes
A
- Largest of the white blood cells
- Gray-blue cytoplasm
- Dark blue-purple nucleus is often kidney-shaped
- Function as macrophages
- Important in fighting chronic infection
- 100–700 monocytes per cubic millimeter of blood (4–8 percent of WBCs)
30
Q
Platelet plug formation
A
- Collagen fibers are exposed by a break in a blood vessel
- Platelets become “sticky” and cling to fibers (platelet adhesion)
- Anchored platelets release chemicals to attract more platelets – Release ADP and thromboxane A2 to attract more platelets)
- Platelets pile up to form a platelet plug (white thrombus) – becomes tight when reinforced by fibrin threads
31
Q
Coagulation – Blood Clotting
A
- Injured tissues release tissue factor (TF)
- PF3 (a phospholipid) interacts with TF, blood protein clotting factors, and calcium ions to trigger a clotting cascade
- Prothrombin activator converts prothrombinase to thrombin (an enzyme)
- Thrombin joins fibrinogen proteins into hairlike molecules of insoluble fibrin
- Fibrin forms a meshwork (the basis for a clot)
- Within the hour, serum is squeezed from the clot as it retracts
- Serum is plasma minus clotting proteins
