1. The Blood and heart

2. blood

3. Composition and Functions of Blood
Components
Connective tissue
Living cells (formed elements) are suspended in a non living fluid matrix (plasma)
Physical Characteristics and Volume
slightly alkaline (pH )
Accounts for about 8% of body weight
Volume is 5-6 liters
Plasma makes up 55% of volume and formed elements make up 45%

6. Plasma The liquid part of the blood
Over 100 different substances are dissolved in the fluid
Nutrients, electrolytes, gases, hormones, plasma proteins, various wastes

7. Plasma Proteins Most abundant solutes in the plasma
Made by the liver (except antibodies and hormones)
Albumin
Carrier to shuttle certain molecules through circulation
Blood buffer
Contributes to osmotic pressure (keeps water in the blood)
Clotting proteins
Stem blood loss after injury
Antibodies
Protect body from pathogens

8. Formed Elements Erythrocytes (red blood cells)
Function to ferry oxygen in the blood to all cells of the body
Carry hemoglobin
Iron bearing protein that carries the oxygen
Anucleated (without a nucleus)
Makes them biconcave disks
Can roll up to fit through capillaries
Have large surface area perfect for gas exchange
Normally about 5 million cells per cubic millimeter of blood

10. Formed Elements cont. Leukocytes (white blood cells) Platelets
4,000-11,000 per square millimeter of blood
Part of the immune system
Can leave the blood vessel
Platelets
Fragments of megakaryocytes
Megakaryocytes are cells that are housed in the bone marrow, only their pieces are found in the blood
300,000 per square millimeter
Needed for clotting blood during vessel damage

12. Hematopoiesis Occurs in the red bone marrow
After the cells mature they are discharged into the blood stream
On average 100 billion new cells are made every day
All formed elements originate from a hemocytoblast stem cell

14. Formation of Red Blood Cells
Live only days
Remains are eliminated in the spleen and liver
Rate of production is controlled by a hormone erythropoietin
Made by the kidneys in response to blood oxygen levels

15. Formation of White Blood Cells and Platelets
Stimulated by hormones
Colony stimulating hormone
Interleukins
Released in response to inflammatory chemicals, bacterial toxins, and increased body temperature

16. Hemostasis

17. Hemostasis Normally takes 3-6 minutes Step 1: Vascular spasm
Immediate response to blood vessel injury is vasoconstriction
Also stimulation of pain receptors and release of serotonin
Spasms narrow the blood vessel at that point decreasing blood loss until clotting can occur
Step 2: Platelet plug forms
When vessels are broken the underlying collagen fibers are exposed
Platelets become sticky and cling to the damaged site
These anchored platelets release chemicals that enhance the vascular spasms and attract more platelets

18. Hemostasis cont Step 3: Coagulation events occur
Tissue factor is released
PF3 interacts with vitamin K and calcium ions to form an activator that triggers the clotting cascade
The cascade leads to the formation of a fibrin meshwork that traps the red blood cells

19. The cardiovascular system