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Biomedical Innovations Unit 3
Tissues of Life
A Focus on Blood
Blood Introduction
• 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
Functions Of Blood
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
COUNTER-CURRENT
EXCHANGE
Composition of Blood
•
Contains cellular and liquid components
•
•
•
•
Liquid Portion: ~ 55% plasma
Cellular Portion: ~ 45% formed elements
Normal blood pH is ~7.35-7.45 (neutral)
Blood volume
• Varies inversely with body fat
• Blood volume as body fat
Volume:
• Assess: Blood pressure
• Calculate: Radioactive dye
Units:
• 1 unit donated = ~ 1 pint (0.5L)
• 1 unit accepted = ~0.75 pint
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?
Composition of 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)
Composition of Blood - Plasma
Figure 19.1b
Composition of Blood – Formed Elements
Figure 19.1c
ID the Formed Elements
• Be able to identify any of the formed
elements to RBC, WBC, or Platelet.
Lecture 1a - Review Break
• Visualize the Composition of Blood
• Microscopy & Blood Cell Identification
Lab
Lecture 1b –
Overview: Composition of Blood
• Hematocrit or Packed Cell Volume (PCV)
• measure of % RBC
•
Males: 47% ± 5%
Females: 42% ± 5%
Figure 17.1
Erythrocytes – Red Blood Cells (RBCs)
•
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/mm3
• Males: 5.2 – 5.8 million cells/mm3
•
Made in the red bone marrow in long bones,
cranial bones, ribs, sternum, and vertebrae
•
Average lifespan is 100 – 120 days
RBC Structure And Function
•
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?
Hemoglobin
•
•
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 O2 molecule
•
How many O2 molecules can each hemoglobin combine
with?
• What is the term for when
hemoglobin binds with O2?
•
•
CO2?
Are either a reversible reaction?
Leukocytes – White Blood Cells (WBCs)
•
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
White Blood Cells
Type Of White Blood
Cells
% By Volume Of WBC
Description
Function
Neutrophils
60 – 70 %
Nucleus has many
interconnected lobes; blue
granules
Phagocytize and destroy
bacteria; most numerous
WBC
Eosinophils
2–4%
Nucleus has bilobed nuclei;
red or yellow granules
containing digestive
enzymes
Play a role in ending allergic
reactions
<1%
Bilobed nuclei hidden by
large purple granules full of
chemical mediators of
inflammation
Function in inflammation
medication; similar in
function to mast cells
20 – 25 %
Dense, purple staining,
round nucleus; little
cytoplasm
the most important cells of
the immune system;
effective in fighting infectious
organisms; act against a
specific foreign molecule
(antigen)
4–8%
Largest leukocyte; kidney
shaped nucleus
Transform into
macrophages; phagocytic
cells
Basophils
Lymphocytes (B Cells
and T Cells)
Monocytes
Lymphocyte
•
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
Platelets
•
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
Summary of Formed Elements
Table 17.1
Review Activity Break
• Blood Disorders
Blood Cell Formation
• 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
Cell Lines in Blood Cell Formation
• 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
Cell Lines in Blood Cell Formation
• 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
The Blood Throughout Life
• 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
RBC life span and circulation
•
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
Red Blood Cell Turnover
Figure 19.5
Clotting Mechanisms
•
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
Clotting Cont.
• What two conditions increase clotting?
• What two conditions decrease clotting?
• How are clots removed?
• Fibrinolysis
Review Activity Break
You should be able to…
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
•
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Antigen vs. antibody
Coagulation vs. agglutination
Identify and describe the following
blood disorders/conditions:
• Leukemia
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Leukopenia
Leukocytosis
Anemia
Polycythemia
Blood doping
Sickle-cell anemia
Embolus
Thrombus
Erythroblastosis fetalis