Circulation and Immunity

1.1 The Heart

1.2 Blood Vessels

1.3 Blood

1.4 Cardiovascular Disease

1.5 The Immune System

1.1 The Heart

• The main functions of the circulatory system are:

1. To transport gases, nutrients and waste materials

2. To regulate internal temperature3. To transport hormones4. To protect against disease

1.1 The Heart

• Stroke volume is the volume of blood pumped in one beat

• Cardiac output is the volume of blood pumped in one minute

• CO = SV x HR

1.1 The Heart

• The heart is a set of two pumps• The right side of the heart pumps blood to the

lungs and back to the heart (pulmonary circulation)

• The left side of the heart pumps blood to the body systems and back to the heart (systemic circulation)

• Coronary circulation is blood flow to the heart muscles

1.1 The Heart

• The heart beats due to electrical signals that coordinate the contraction of the chambers

1. Diastole occurs when the ventricles of the heart are relaxed

2. Systole occurs when the ventricles of the heart are contracted

1.1 The Heart

• Factors that influence heart rate include:1. Physical activity2. Emotions3. External temperature• For healthy living, exercise should

attempt to attain a target heart rate

1.2 Blood Vessels

• The major arteries and veins make up the pulmonary and systemic pathways

• Artery: thick-walled blood vessel that carries blood away from the heart

• Vein: thin-walled blood vessel with valves that carries blood toward the heart

• Capillary: tiny blood vessel that connects the smallest branch of an artery (arteriole) to the smallest branch of a vein (venule)

1.2 Blood Vessels

• Major blood vessels include:1. Aorta2. Vena Cavae3. Pulmonary Arteries4. Pulmonary Veins• Blood pressure is the pressure exerted by

blood against the walls of blood vessels

1.2 Blood Vessels

• Blood pressure is measured in units of mmHg

• Blood pressure is measured as systolic pressure over diastolic pressure

• In general, the pressure in arteries is greatest and in veins is least

• Blood pressure is measured with a sphygmomanometer

1.3 Blood• Blood is a mixture of a fluid portion and a

formed portion• The fluid portion is called plasma and makes

up 55% of blood volume• The formed portion is made up of cells1. Red blood cells (erythrocytes): small cells

filled with hemoglobin to carry oxygen and carbon dioxide

1.3 Blood1. White blood cells (leucocytes): many types of

cells that respond to disease2. Platelets (thrombocytes): cell fragments that

control blood clotting

1.4 Cardiovascular Disease

• Cardiovascular disease is the leading cause of death in Canada

• Arteriosclerosis is hardening of the arteries• Arteriosclerosis can lead to heart attacks,

strokes and embolisms• Arteriosclerosis can be treated by medication,

angioplasty or coronary bypass

1.4 Cardiovascular Disease

• Cardiovascular disease is linked to consumption of fats and cholesterol

• LDL cholesterol: increases risk of cardiovascular disease

• HDL cholesterol: decreases risk of cardiovascular disease

• Certain fats can raise or lower LDL and HDL cholesterol

1.4 Cardiovascular Disease

• Certain fatty acids are essential including omega-3 and omega-6

• Tradition Inuit diet is rich in omega-3 fatty acids

• Other cardiovascular diseases include aneurysms, septal defects and valvular diseases

1.5 The Immune System

• A pathogen is a disease causing agent• Your body defends against pathogens in the

following ways1. Protective barrier2. Sweat and oil secretions3. Blood clotting4. Various other secretions5. White blood cells

1.5 The Immune System

• Pathogens may be food-borne, water-borne, blood borne or air-borne

• Microscopic pathogens include1. Bacteria2. Protozoa3. Fungi4. Viruses

1.5 The Immune System

• The immune response to a viral infection includes1. Macrophages2. Helper T Cells3. Killer T Cells4. Supressor T Cells5. Memory Cells6. Antibodies7. B Cells

1.5 The Immune System

• Vaccines use the bodies natural immune response to create immunity to infections

• Vaccines have significantly improved human health globally

• Autoimmune diseases such as multiple sclerosis, arthritis and lupus are the result of the immune system attacking normal body cells