A Focus on Blood

• Blood is a special Connective Tissue, and is the major component of the
Circulatory System
• Connective tissue is a group of cells that collectively function to support, connect, and/or separate other tissues and organs.
• The Circulatory System is comprised of two sub-systems:
1. Cardiovascular System
• Includes network of blood vessels, blood, and heart
• Major function is to transport nutrients, gases and hormones to cells and wastes from cells for excretion outside the body
2. Lymphatic System
• Includes network of lymph vessels, the lymphocyte white blood cell, and lymphoid organs (tonsils, spleen, thymus, bone marrow, and lymph nodes)
• Major functions are to return fluid that escapes from blood vessels back to the bloodstream AND fight infections and give immunity to disease

1. Transportation
•
Blood transports dissolved gases, nutrients, hormones and metabolic wastes
2. Protection & Clotting
•
White Blood Cells (WBC) protect the body against foreign molecules
•
Platelets (cell) and clotting proteins in blood minimize blood loss when a blood vessel is damaged (clot)
3. Regulation
•
Blood regulates the pH and electrolyte composition of the interstitial fluids (fluid between cells)
•
Blood regulates body temperature: transfers heat via countercurrent exchange

•
Contains cellular and liquid components
•
Liquid Portion: ~ 55% plasma
•
•
Cellular Portion: ~ 45% formed elements
Normal blood pH is ~7.35-7.45 (neutral)
Volume:
•
Assess: Blood pressure
•
Calculate: Radioactive dye •
Blood volume
•
Varies inversely with body fat
Units:
•
1 unit donated = ~ 1 pint (0.5L)
•
1 unit accepted = ~0.75 pint
•
Blood volume as body fat
Packed RBC (prBC)
•
Males typically have 5 to 6 liters (~10.5 to 12.5 pints)
•
Females typically have 4 to 5 liters (~8.5 to 10.5 pints)
•
How can blood volume be determined?
• How much is a “unit” of donated blood?

•
55% Plasma
•
92% - Water
•
7% - Proteins (fibrinogen, hormones, albumins & globulins)
•
1% - other solutes (ions, gases, nutrients, wastes, etc.)
•
45% Formed Elements
•
99.9% - erythrocytes (Red Blood Cells - RBCs)
•
0.1% - leukocytes (White Blood Cells - WBCs) & thrombocytes (Platelets)

Figure 19.1b

Figure 19.1c

•
Be able to identify any of the formed elements to RBC, WBC, or Platelet.

•
Visualize the Composition of Blood
•
Microscopy & Blood Cell Identification
Lab

•
Hematocrit or Packed Cell Volume (PCV)
• measure of % RBC
•
Males: 47% ± 5% Females: 42% ± 5%
Figure 17.1

•
Oxygen-transporting cells
•
7.5 µm in diameter (diameter of capillary 8 – 10µm)
•
Most numerous of the formed elements
•
Females: 4.3 – 5.2 million cells/mm 3
•
Males: 5.2 – 5.8 million cells/mm 3
•
Made in the red bone marrow in long bones, cranial bones, ribs, sternum, and vertebrae
•
Average lifespan is 100 – 120 days

•
Have no organelles or nuclei
•
Significance?
•
True for all species?
•
Hemoglobin – oxygen carrying protein
•
Each RBC has 200-300 million hemoglobin molecules
•
Biconcave shape
•
Significance?

•
Comprised of four protein chains, each called a globin.
•
Each globin is bound to a red pigment, called a heme molecule.
•
Contains a single Fe atom
•
Each Fe atom can bind to a single O
2 molecule
•
How many O
2 with?
molecules can each hemoglobin combine
•
What is the term for when hemoglobin binds with O
2
?
•
CO
2
?
•
Are either a reversible reaction?

•
Protect the body from:
• infectious microorganisms
•
Cancerous cells
•
Foreign particles
•
Typically, function outside the bloodstream in loose connective tissue
•
Diapedesis - circulating leukocytes leave the capillaries and enter the interstitial fluid
•
Exception?
•
WBCs have a nucleus and are larger than RBCs
•
Most produced in bone marrow
•
Exception?
•
Lifespan of 12 hours to several years

Leukocytes – White Blood Cells (WBCs)
•
Two types of leukocytes
•
Granulocytes
•
Agranulocytes
•
Relative WBC Count
•
Never
•
Let
•
Monkeys
•
Eat
•
Bananas
Figure 17.5

Type Of White Blood
Cells
Neutrophils
% By Volume Of WBC
60 – 70 %
Eosinophils
Basophils
Lymphocytes (B Cells and T Cells)
Monocytes
2 – 4 %
< 1 %
20 – 25 %
4 – 8 %
Description Function
Nucleus has many interconnected lobes; blue granules
Nucleus has bilobed nuclei; red or yellow granules containing digestive enzymes
Bilobed nuclei hidden by large purple granules full of chemical mediators of inflammation
Dense, purple staining, round nucleus; little cytoplasm
Largest leukocyte; kidney shaped nucleus
Phagocytize and destroy bacteria; most numerous
WBC
Play a role in ending allergic reactions
Function in inflammation medication; similar in function to mast cells the most important cells of the immune system; effective in fighting infectious organisms; act against a specific foreign molecule
(antigen)
Transform into macrophages; phagocytic cells

•
Compose 20 – 45% of WBCs
•
The most important cells of the immune system
•
Nucleus – stains dark purple
•
Effective in fighting infectious organisms
•
Act against a specific foreign molecule (antigen)
•
Two main classes of lymphocyte
•
T cells – attack foreign cells directly
•
Active in cell mediated immune response
•
B cells – multiply to become plasma cells that secrete antibodies
•
Active in the humoral immune response
Figure 17.4d

•
Structure
•
Small, nearly colorless bodies appearing as irregular spindles or oval disks (~2-4 μm)
• originate in bone marrow from giant cell megakaryocyte
•
Functions
•
Hemostasis
•
Regulation of blood flow
•
Coagulation, or blood clotting

Table 17.1

•
Blood Disorders

•
Hematopoiesis – process by which blood cells are formed
•
100 billion new blood cells formed each day
•
Takes place in the red bone marrow of the humerus, femur, sternum, ribs, vertebra and pelvis
•
Red marrow – actively generates new blood cells
•
Contains immature erythrocytes
•
Remains in epiphyses, girdles, and axial skeleton
•
Yellow marrow – dormant (can become active if needed)
•
Contains many fat cells
•
Located in the long bones of adults

•
All blood cells originate in bone marrow
•
All originate from one cell type
•
Blood stem cell (pluripotential hematopoeitic stem cell)
•
Lymphoid stem cells - give rise to lymphocytes
•
Myeloid stem cells - give rise to all other blood cells

•
Genesis of erythrocytes
(erythropoiesis)
•
Committed cells are proerythroblasts
•
Remain in the reticulocyte stage for 1–2 days in circulation
•
Loss of nucleus
•
Formation of leukocytes
(leukopoiesis)
•
Granulocytes form from myeloblasts
•
Monoblasts enlarge and form monocytes
•
Platelet formation
(thrombopoiesis)
•
Form from megakaryoblasts
• break apart into platelets

•
First blood cells develop with the earliest blood vessels
•
Late in the second month the liver and spleen take over blood formation
•
Bone marrow becomes major hematopoietic organ at month 7

•
Replaced at a rate of approximately 3 million new blood cells entering the circulation per second
•
Damaged or dead RBCs are recycled by phagocytes
•
Components of hemoglobin individually recycled
•
Heme stripped of iron and converted to biliverdin, then bilirubin
•
Iron is recycled by being stored in phagocytes, or transported throughout the blood stream bound to transferrin

Figure 19.5

•
Know the general stages of blood clotting
•
Stage 1: Source of damage
•
Stage 2: prothrombin
 thrombin
•
Calcium, prothrombin activator
•
Stage 3: fibrinogen
 fibrin
•
Calcium, thrombin
•
Be able to identify the key difference between intrinsic and extrinsic pathways
•
Stage 1

•
What two conditions increase clotting?
•
What two conditions decrease clotting?
•
How are clots removed?
•
Fibrinolysis

Identify and describe:
•
The different types of tissues
•
Functions of the blood
•
Blood composition
•
Plasma & Formed Elements
•
% Hematocrit
•
Blood Cell Formation
•
The process of clotting
•
Blood type based on tests and genetic inheritance
•
Antigen vs. antibody
•
Coagulation vs. agglutination
Identify and describe the following blood disorders/conditions:
•
Leukemia
•
Leukopenia
•
Leukocytosis
•
Anemia
•
Polycythemia
•
Blood doping
•
Sickle-cell anemia
•
Embolus
•
Thrombus
•
Erythroblastosis fetalis