Human Systems:Circulatory System

Blood

Blood

• Fluid connective tissue

• Circulates various substances (O2 and nutrients, hormones to different parts of your body)

• Regulation of body temperature• About 5L of blood in human adults

• Blood is a part of the cardiovascular system (other include the heart and blood vessels)

Components of blood

• Blood contains– plasma (fluid component)– Blood cells (suspended component)

• Plasma– Contains dissolved substances (water, minerals, proteins,

carbohydrates, other complexes, etc.)

• Blood cells– RBC - Red blood cells (hemoglobin – transport of gases)– WBC - White blood cells (immune system – destroy pathogens-defense

against infections)– Platelets (involved in blood clotting)

Blood cells

• Red blood cells– Transport oxygen– Contain hemoglobin– Most abundant cell type

Blood cells

• Platelets– Small in size, pieces of larger cells found in bone marrow– Lasts for 5-10 days– Role in blood clotting

Blood cells

• White blood cells– Destroy pathogens– Help in wound cleaning

• Modes of action– Some WBCs produce antibodies– Some WBCs produce other chemicals against pathogens– Other eliminate dead or damaged body cells

Blood pressure• When heart contracts, blood is pushed out• The force blood exerts on the walls of arteries is known as blood

pressure

• Expressed in terms of millimeters of mercury (mm Hg)• Blood pressure is expressed by two numbers - systolic and diastolic

• Systolic pressure – pressure in arteries when heart contracts• Diastolic pressure - pressure in arteries when heart relaxes

• Healthy blood pressure: systolic 120 mm Hg, diastolic 80 mm Hg• Pulse – rhythmic throbbing of arteries when blood is pumped by

heart (around 60 - 70 per minute)

Blood types• ABO system

– A, B, AB or O– Depends on the type of antigens (chemicals) on RBC– Type A has antigen A, B has B,AB has AB and O has none.– It may also depend on the antibodies on the plasma– Blood transfusion means blood injection

Blood types

• Rh System– Another type of antigen on RBC– If antigen if present then Rh+– If absent then the individual is Rh-

– Rh system and transfusion

Blood disorders

• Hemophilia– Problem in blood clotting– Protein required for clotting is missing

• Leukemia– Blood cancer– Healthy blood cells are not produced

• Sickle cell anemia– Mutation in hemoglobin– Results is deformed RBCs

Cardiovascular system

Cardiovascular system

• Circulatory fluid (blood)• Channels / tubes (blood vessels)• Pumping device (heart)

• Transport of substances• Regulation of body temperature• Maintenance of homeostasis

The heart

• Muscular organ• Divided into four compartments (chambers)• Upper chambers: Atrium• Lower chambers: Ventricles• Left and right sides of the heart are separated by wall• The right side of the heart pumps oxygen poor blood to the

lungs and left side pumps oxygen rich blood to the body.• Valves prevent back flow of blood• Repeated opening and closing of valves produce heart beat

The heart

The heart

Blood vessels

• Hollow tubes for flow of blood• Some contain valve to prevent backward blood flow• Three types• Arteries

– Carries blood away from the heart (oxygenated blood)– Pulse is caused by flow of blood into arteries

• Capillaries– Narrow blood vessels– Allows exchange between body cells and blood

• Veins– Blood enters from arteries to veins– Carry blood towards heart (deoxygenated)

Blood vessels

Types of circulation

• Pulmonary (The circulation of blood between lungs and heart-Oxygen rich)

• Systemic (The circulation of blood between the heart and rest organs of the body-Oxygen Rich.)

Cardiovascular problems

• Atherosclerosis– Cholesterol and lipids accumulate in blood vessels– This causes narrowing & clogging of vessels and decrease in elasticity

• High blood pressure– Hypertension– Narrowing or constriction of blood vessels increases pressure– Stroke - blockage or rupture of blood vessels in brain• Heart Attack- When heart muscle cells die or get damanged.• Heart failure- when heart cant pump enogh blood to meet body needs-organs are damaged by lack of oxygen (brain, kidneys)