The Tunics that make up the walls of arteries and veins and their functions

1. Tunica Interna/Intima - Single layer of endothelial cells. Responsible for diffusion and reducing friction

2. Tunica Media - Made of smooth muslce

3. Tunica Externa Adventitia - Outer layer protecting the surface of the blood vessel.

Types of blood vessels

1. Arteries (and arterioles) - Thick walls, smooth muslce with elastic tissue to withstand high pressure -Carry blood away from heart -Largest artery- Aorta

2. Capillaries -smallest and most numerous blood vessel. -single-cell thickness for easy diffusion -exchange of material between blood and body cells occurs here.

3. Veins (and venules) -One way valves in thin-walled vessels surrounded by a thin layer of smoothe muscle giving low resistance to blood flow. -blood flow assisted by skeletal muscle contractions -returns blood to heart -biggest veins- Vena Cavae

-expressed as a ratio of systolic pressure over diastolic pressure.

-Measured in millilitres of of Hg

Diastolic and Systolic blood pressure

Diastolic - blood pressure when ventricles are relaxed and filling

Systolic - Blood pressure when ventricles are contracting

Three things that effect blood pressure

1. Rate and force of the heartbeat

2. Volume of blood pumped in each heartbeat (stroke volume)

3. Resistance of blood vessels to the flow of blood (peripheral resistance)

Four components of blood

1. Plasma

2. Erythrocytes (red blood cells)

3. Leukocytes (white blood cells)

4. Platelets

1. 90% water 10% nutrients, gases, salts, hormones and...

Proteins (3)

1. Albumins - responsible for osmotic pressure and transportation of F.A., thyroid hormones, and steroid hormones

2. Globulins - attack foreign proteins and pathogensm also called immunoglobins or antibodies

3. Fibrinogen - functions in blood clotting, form strands of fibrin

-Contain red pigment hemoglobin

-Binds to and transports oxygen and C02

-Most abundant blood component

-No nucleus, life span: 120 days

Disorders: Anemia (low), Polycythemia (excess)

1. Neutrophils- very active in phagocyting bacteria, present in large amounts of pus of wounds, most common (60% WBC)

2. Basophils- discharge granules containing histamine and heparin into damaged tissue to promote inflammation and blood flow to damaged areas. Less than 1% WBC.

3. Eosinophils- attack parasites, control allergic reaction, produces heparin (prevents blood clots) and histamines, causes inflammatory reaction, 2% WBC

Lymphocytes- role in immunity (2 types)

-T-Lymphocytes- cellular immunity

-B-Lymphocytes- produce antibodies

2. Monocytes- phagocytes that are very large. Disorders: Leukopenia- low number of WBC's. Leukocytosis- high number of WBC's

Leukemia- high WBC count after an infection

Cell fragments that aid in blood clotting.

Disorder: hemophilia - inherited disorder resulting in inadequate platelet production.

Blood clotting cascade

1. Platelets (thrombocytes) cling to the site, forming a small mass of platelets called a chitethrombus, or platelet plug.

2. Platelets release seratonin, which causes tmuslces in the vessels to spasm, causing them to narrow (vasocontriction), decreasing blood flow

3. Thromboplastin is released by injured tissue and platelets. Causes prothrombin (in plasma) to convert it into thrombin

4. Thrombin joins fibrinogen forming long hairlike molecules, fibrin, which form a network of strands that trab RBC's forming the clot.

1. Transport dissolved gases, nutrients, hormones, and metabolic wastes.

2. Regulate the pH and electrolyte composition of fluids

3. Restrict fluid loss through damaged vessels.

4. Defend the body against toxins and pathogens.

5. Regulate body temperature

A: has A antigens and anti-B antibodies

B: has B antigens and anti-A antibodies

AB: has A and B antigens and no antibodies

O: Has no antigens and anti-A and B antibodes

AB- universal reciever

O- universal donor

1. Epicardium- outermost layer, thin, serous membrane of the pericardium

2. Myocardium- middle layer, composed of cardiac muscle

3. Endocardium- innermost layer, appears milky white, lines chambers of heart and prevents friction.

Parietal Pericardium- lines inner surface of the pericardial sac.

Visceral Pericardium-(epicardium)- covers surface of the heart.

1. Heartbeat is initiated by Sinoatrial (SA) node (pacemaker), located in the right atrium

2. Contraction of the right and left atria occurs.

3. Impulse is sent to the Atrioventricular (AV) node in the inferior portion of the right atrium

4. Impulse travels into the AV bundle (Bundle of His), which branches into the right and left ventricle nerves called Bundle Branches.

The impulse travels through the Purkinje fibres, causing the ventricles to contract.

Location of SA and AV nodes, AV Bundle, bundle branches, and Purkinje fibres

1.  SA node - Right Atrium (superior)

2. AV node - Right Atrium (inferior)

3. AV Bundle (Bundle of His) - Superior Septum wall

4. Bundle branches - Septum and ventricle walls

5. Purkinje fibres - Ventricular walls

Three Circulation Circuits

1. Pulmonary Circuit - right side of heart recieves blood which is pumped to the lungs.  High in CO2.

2. Systemic Circuit - pumps blood from lungs to the other body stsems.  Blood high in O2.

3. Coronary Circuit - Blood pumped from left side of heart to heart tissue.  Returns to right side.

Diseases of the Circulatory System

1. Atherosclerosis - fatty deposits on walls of arteries causing blockage and clots. (Blockage of coronary arteries is called Myocardial infarction [heart attack])

2. Blood clots in a cerebral artery of a ruptured artery causes a stoke.

3. Hypertension - very high blood pressure causes heart to work harder.  This can cause heart fatigue and heart stops beating (Heart failure)