Cardiovascular System I
A&P II Lecture

• Transportation
– O
2
, CO
2
, Nutrients, Wastes, Hormones, Heat
• Regulation
– Temperature
– pH
– Osmotic fluid balance
• Protection
– Immune functions
– Clotting

• Temperature
– 100.4
o F
•
Viscosity
– 5 x more viscous than water
• pH- 7.4
•
Volume
– Men- 5-6 liters, 1.3-1.8 gallons
– Women – 4-5 liters, 1.1 –
1.3 gallons

•
Albumens55-60%
– Viscosity, Osmotic pressure, Transport
•
Globulins
– 35-38%
– Immunoglobulins
• Disease fighting antibodies
– Transport globulins
•
Fibrinogen4-7%
– Blood clotting

• The liver
– 90%
– Albumens, fibrinogen, transport globulins
• Lymphocytes
– Immunoglobins

•
Thrombocytes
– Platelets
•
Leukocytes
– White cells
•
Erythrocytes
– Red cells

ERYTHROCYTES
Functions
• Carry
O2, CO2
• Major determinant of blood viscosity
Hemoglobin
-Gases are carried on 280 million molecules of hemoglobin
Hemoglobin makeup
-Four globinsamino acid chains
-Four hemeseach with an iron molecule in center

•
Structure
– Biconcave
– No nucleus

1.
Large surface area
2. Form stacks called rouleaux
•
Allow smooth flow through vessels
3. Bend to squeeze through capillaries

1. More space to carry O
2
2. Don’t use O
2
3. Flows easily through capillaries

• Lack of nucleus and mitochondria
– Cannot divide
– Live 120 days

• Formation of blood cells
• Formed in the red bone marrow
•
Hemocytoblasts
– Stem cells
– Divide to form red + white cells

• There are 3 types:
–
Totipotent stem cells: within 48 hours of fertilization. These cells are each capable of becoming a complete entity (organism)
– Multipotent stem cells: Germ cells – Ectoderm,
Mesoderm and Endoderm. These cells are in the embyonic stage – capable of forming different
tissues. (read about each and know what they form)
– Pluripotent stem cells: These are found in tissues and organs. They form ALL the different cells of the SAME tissue – for example Hemocytoblast, forms all the cells of Blood.

Erythropoiesis
•
Form at rate of 3 million/sec
•
Takes 12-15 days
•
Regulated by hormone erythropoietin
– Produced by the kidney
– Stimulates red cell production
– Works through negative feedback loop
•
How might kidney failure affect hematocrit?

1. Hemocytoblasts
Become
Erythrocyte colony forming unit (CPU)
• Have a nucleus
• Begin forming hemoglobin

2. Become Erythroblasts
– Hemoglobin increases
– Nucleus shrinks
– Cell shrinks

RBC FORMATION II
3. Recticulocyte
-Loses nucleus
-Enters circulation
4. Mature erythrocyte

RED BLOOD CELL- BREAKDOWN
The body saves + reuses parts
1.
Macrophages engulf dying red cells
2.
Hemoglobin broken down
•
Globin –amino acids released + reused
•
Heme –converted to bilirubin

3. Bilirubin
-Goes to liver
-Excreted in bile
-Removed with feces + urine

4. Iron
•
Binds to a plasma protein
•
Returns To bone marrow

Defend against infections
Remove toxins and wastes
Movements
1.
Move out of blood into tissues
2.
Attracted to chemicals from pathogens, damaged cells
3.
Some are phagocytotic
•
Engulf cells, wastes

• Granular
• Neutrophils
• Basolphils
• Eosinophils
• Agranular
• Lymphocytes
• Monocytes

• 60-70% of white cells
• First at site of injury
• Phagocytize antibody-marked bacteria

• Release inflammation-producing prostoglandins
• Release phagocyte-attracting leukotrines
• Live
10 hours

•
2-4% of white cells
• Phagocytize antibody-marked bacteria and protozoa and debris
• Release toxins to kill invaders
• Kill parasitic worms
•
Increase during allergic reactions
• Reduce inflammation

•
1% of white cells
• Release histamine-causing inflammation
• Release heparin prevents clotting
• Attract other cells to site of injury
• Increase during allergic reactions, leukemias, diabetes, hypothyroidism

•
3-8% of white cells
• Leave blood to become
Macrophages
•
Engulf microbes particularly viruses
• Attract other white cells to site of attack
•
Clean debris, dead cells

•
25-33% of white cells
• Move between tissues and blood
• Three types
•
T cells
•
B cells
•
NK cells

•
Cellular immunity
• Attack foreign cells
• Attract other lymphocytes

•
Humoral immunity
• Produce antibodies
• Chemicals that mark or destroy foreign antigens

• Detect and destroy abnormal tissue cells-cancer

• Fragments of cells
• Circulate 9-12 days
• Functions
• Release chemicals that begin process of blood clotting
•
Dissolve old clots
•
Phagocytize bacteria
• Form a plug at site of injury
•
Contract wound to aid healing

• Stoppage of bleeding
• Steps
•
Vascular Spasm
• Vasoconstriction
• Platelet plug formation
• Platelet plug
•
Blood clotting

Rapid constriction of injured vessel
Causes
• Pain receptors in wall
– lasts minutes
• Injury to smooth muscle
• Platelets release serotonin
– Can last hours http://www.mhhe.com/biosci/esp/2
002_general/Esp/folder_structure/tr
/m1/s7/trm1s7_3.htm

•
Vascular contraction
–
Smooth muscle wall constricts
–
Rapid
–
Reduces blood loss

• Slows blood loss
• Provides time for clotting to begin

Within 15 seconds after injury
• Platelets contact sticky collagen fibers in damaged vessel wall
• Platelets enlarge and become sticky-Platelet aggregation
• Platelets form mass Platelet plug

•
Blocks blood loss
At the same time
• Platelets release clotting factors

ADP
• Released by endothelial cells and then by platelets
• Stimulates platelet aggregation
Thromboxane A
2
• Stimulates platelet Aggregation
Serotonin
• Stimulates vasoconstriction
(smooth muscle contraction).

• Blood forms gel
• Begins in 15-30 seconds
• Requires 3-5 minutes
• Includes fibrin and blood cells

• Requires
– 13 procoagulants
– Vitamin K
• For procoagulant synthesis
– Ca ++
• Normally inhibited by
– Anticoagulants
-

Takes seconds
1. Blood is released into tissues surrounding blood vessels
2. Damaged tissue cells release tissue factor (tissue thromboplastin) and Ca ++

3. Leads to the activation of clotting factor X

Takes minutes
1.
Blood vessel endothelium ruptures
2. Collagen fibers are exposed
3. Platelets cling and attract + release
•
Platelet factors
• Ca ++
4. Many steps to formation of
Clotting factor X

BASIC STEPS-COMMON PATHWAY
1. Factor X Prothrombinase
2.Prothrombin
Prothrombinase Thrombin
3. Fibrinogen Thrombin Fibrin threads
• Threads entrap red cells, platelets, and plasma in clot
4. Clot shrinks
• Pulls vessel together

1.
Heparin + Antithrombin
•
Produced by basophils in small amounts
(heparin) and Liver (antithrombin)
•
Inhibit thrombin formation
2.
Smooth lining of blood vessels
•
Will not attract platelets
•
Secretes chemicals that repel platelets
(prostacyclin)

FACTORS PREVENTING CLOTTING
3. Rapid flow of blood
Prevents platelets from sticking
• Conditions that slow flow
• Roughened blood vessels -allow platelets to cling
• Atherosclerosis
• Burns
• Long immobilization
– Allows clotting factors to build by slowing blood flow