The problem How do we get nutrients and gases to every cell of the body?

The Circulatory System What is the circulatory system? What are its functions?

Circulatory system - structure Consists of  Blood – the medium  The Heart – the pump  Blood Vessels – the pathways

Function Transports substances within the body  Nutrients/waste products  Gases – oxygen/carbon dioxide  Hormones  Immune system Also assists with temperature regulation

Blood

Plasma Makes up 55% of blood volume  90% water  7% plasma protein Fibrinogen, albumins and globulins – assist in transport and clotting  2% dissolved solutes Nutrients, wastes, hormones  1% dissolved salts Sodium, calcium, potassium, and magnesium chloride, bicarbonate, phosphate and sulfate

Formed elements

Formed Elements Erythrocytes (gk Erythro = red)  Red blood cells  Carry oxygen Leukocytes (gk Leuco = white)  White blood cells  Immune system - defence Platelets  Clotting

Red Blood Cells

aka erythrocytes  Carry oxygen and carbon dioxide  Biconcave  Do not have a nucleus  Produced in bone marrow and stored in the spleen  Contain hemoglobin – the protein which carries oxygen and carbon dioxide

Hemoglobin

Each hemoglobin has 4 subunits Each subunit has an iron atom which associates with one oxygen/carbon dioxide molecule A shortage of hemoglobin is called anemia

White Blood Cells Part of the immune system Defends the body against invaders Pus can form when there is an infection  A mixture of living and dead white blood cells and bacteria Responds to infection by:  Enveloping foreign bodies  Destroying infected cells  Signalling the body – inflammation, fever

Platelets

Contain the protein fibrinogen Responsible for clotting

Blood Types What are they? How are they determined?

Blood types The four blood types are A, B, AB and O. They are determined by the presence (or absence) of the A and B antigens on the cell A separate antigen (Rh factor) determines whether or not it is positive or negative

Donating Blood Recipient Donor ABABO A B yes O no

The Heart Inferior Vena Cava Right Ventricle Right Atrium Pulmonary Veins (right) Pulmonary Artery (right) Superior Vena Cava Aorta Pulmonary Artery (left) Pulmonary Vein (left) Left Atrium Left Ventricle Septum Semi-lunar Valve [pulmonary] Semi-lunar Vavle [aortic] Atrioventricular (A-V) Valve [tricuspid] Atrioventricular (A-V) Valve [bicuspid/Mitral] Arteries

The Heart Muscled organ used to pump blood Consists of 4 chambers Two types of chambers – atria and ventricles Heart can be divided into left and right sides  Septum – tissue that separates left and right sides

Atria and Ventricles Two types of chambers Atria  Receive blood Ventricles  Pump blood

Left and Right Sides Left side  Receives deoxygenated blood from body  Pumps it to lungs Right side  Receives oxygenated blood from lungs  Pumps it to the body

Two loops Vena cava Right atrium Right Ventricle Pulmonary arteries Lungs/capillaries/alveoli Pulmonary Veins Left atrium Left Ventricle Aorta arteries arterioles capillaries venules veins

Systemic and Pulmonary Circuits Blood travels along two distinct pathways SYSTEMIC CIRCUIT  From the heart to all the tissues and back  Leaving the heart with oxygenated blood and returning with deoxygenated blood PULMONARY CIRCUIT  From the heart to the lungs and back  Leaving the heart with deoxygenated blood and returning with oxygenated blood

Blood Vessels

Arteries – carry blood away from the heart Veins – carry blood towards heart Capillaries – site of diffusion

Arteries

Carry blood away from the heart Thick, muscular walls – epithelial, muscle and connective tissue Elastic Found deep within muscle tissue Blood propelled by heart, blood pressure Arteries branch into smaller arterioles

Veins

Carry blood towards the heart Thin, elastic walls Found near the surface of the skin Contain valves to ensure blood only flows in one direction Blood is propelled by muscular contraction Smaller veins called venules collect blood from capillaries

Capillaries

Site of nutrient exchange/diffusion Extremely narrow – only one red blood cell may pass at a time Extremely thin walls Beds of extremely dense, diffuse blood vessels provide surface area for diffusion

Blood Pressure The force of the blood on the walls of the blood vessels Systolic – while the heart is contracting Diastolic – while the heart is relaxing

Measuring Blood Pressure Measured with a SPHYGMOMANOMETER and a stethoscope

Measuring blood pressure Systolic Pressure Diastolic Pressure Cuff Pressure No pulse Cuff cuts off circulation Pulse Systolic pressure able to overcome cuff pressure No pulse Both systolic and diastolic pressures are greater than Cuff pressure. Blood flows smoothly

Measuring Blood Pressure Inflate cuff until circulation cut off Slowly release pressure Listen Pulse is heard when systolic pressure is reached Pulse stops when diastolic pressure is reached

Blood Pressure A normal systolic pressure is 120 mm Hg A normal diastolic pressure is 80 mm Hg

Blood Pressure What is your blood pressure? What factors do you think affect blood pressure? Design and conduct an experiment to determine one of the factors affecting blood pressure.