AP Bio - Circulation and Gas Exchange

Function of the circulatory system

• transport blood, oxygen, nutrients, and hormones

• remove waste products like carbon dioxide

• distribute heat throughout the body

Why do animals in the lower phylum do not have circulatory system

• Their small size and simple structure allows for diffusion of nutrients, gases, and waste products through their body surface

• If they live in a water based environment, it can provide oxygen and remove waste

Open Circulatory System

• In insects, other arthropods, and most molluscs, blood bathes the organs directly 

• there is no distinction between blood and interstitial fluid and this general body fluid is more correctly called hemolymph

• Blood circulates freely within the body cavity, allowing for the exchange of nutrients and waste.

Veins

• carry blood towards the heart

• carry blood away from capillaries

• venules - the smallest veins, receive blood from capillaries

• are typically low in oxygen content

Arteries

• carry oxygenated blood away from the heart to tissues/organs

• have thicker walls than veins

• carry blood to capillaries; arterioles

Capillaries

• Exchange blood with body cells; have thin walls

• Allow for nutrient and gas exchange between blood and tissues.

Capillary Beds

• sites of chemical exchange between blood and interstitial fluid

• Consist of networks of capillaries that facilitate nutrient and gas exchange.

Animals that have a three chambered

What are the advantages?

• Frogs/Amphibians and Reptiles - 2 atria and 1 ventricle

• More efficient oxygen supply; single circulation and reduced mixing of oxygenated and deoxygenated blood

Vena Cava

• Superior vena cava brings blood from the head, neck, arms, and chest

• Inferior vena cava returns blood from the lower body

Oxygenated Blood

• flows through the systemic circuit

• blood returns from the lungs through the pulmonary veins to the left atrium

• pumped via the left ventricle to the rest of the body

Deoxygenated Blood

• flows through the pulmonary circuit

• body tissues return blood to the right side of the heart through the superior and inferior vena cava, which then pumps it to the lungs

Aorta

• largest vessel in the body

• transports oxygenated blood from the heart to the rest of the body

• branches off the left ventricle

Cardiac Output

• the volume that is pumped into the systemic circuit per minute and depends on both the heart rate and stroke volume

• CO=SV x HR

Pacemaker (SA Node)

• sets the rate and timing at which cardiac muscle cells contract

• is influenced by the nerves, hormones, body temperature, and exercise

• impulses from the SA node travel to the AV node

Atrioventricular (AV) node

impulses are delayed here and then travel to the purkinje fibers

Bundle of His

takes impulses from the AV node and carries them to the purkinje fibers

Purkinje Fibers

facilitate coordinated ventricular contractions by quickly transmitting electrical signals throughout the ventricular muscle tissue

Anemia

• condition where there are fewer red blood cells or hemoglobin than normal in the blood

• prevents the body from getting enough oxygen-rich blood

• caused by iron deficiency, infections, and genetic disorders

Leukemia

• a blood cancer that's caused by abnormal white blood cell production

• caused by gene mutations

Red Blood Cells (Erythrocytes)

• Carry oxygen from the lungs to the tissues

• Produced in the bone marrow by stem cells

• Have no nucleus

Tricuspid Valve

between right atrium and right ventricle, prevents blood from flowing back into the right atrium

Pulmonary Valve

located between right ventricle and pulmonary artery, prevents blood from flowing back into the right ventricle

Mitral Valve

located between left atrium and left ventricle, prevents blood from flowing back into the left atrium

Aortic Valve

located between left ventricle and aorta, prevents blood from flowing back into left ventricle

Systolic Pressure

the higher number in a bp reading and represents the pressure in your arteries when blood is pumped into them

Diastolic Pressure

the bottom number; measures the force of blood against artery walls while the heart is at rest between beats

Heart Attack

• Occurs when blood flow to the heart is blocked

• Blockage usually due to buildup of fat, cholesterol, and other substances in the coronary arteries.

Blood Pressure

the force exerted by circulating blood against the walls of your blood vessels, usually arteries, as the heart pumps blood around your body

Plasma

• Liquid component of the blood, 55% of its volume

• Carries red blood cells, nutrients, waste products, hormones, and antibodies

• Contains water, ions, and proteins

Albumin

• most abundant blood protein and produced by liver

• Maintains BP, transports nutrients and hormones

Globulins

• group of proteins involved in immune responses, blood clotting, and transport

• Immunoglobulins (antibodies) and Beta globulins (oxygen transport)

Fibrinogen

• ESSENTIAL for blood clotting.

• Converts into fibrin which forms a clot to prevent blood loss

Phagocytes

• specific type of white blood cell that has the ability to engulf and destroy foreign particles

• Neutrophils and Monocytes

Clotting

• Platelets activate and adhere to the damaged area

• Then, clotting factors are released and form a mesh-like network called fibrin

• Platelets and red blood cells become trapped in the network

Thrombus

stationary blood clot

Elombus

floating blood clot

Right Atrium/Ventricle

receives oxygen poor blood through vena cavas, pumps into right ventricle, sends to lungs to become oxygenated

Left Atrium/Ventricle

receives oxygen-rich blood from the lungs and pumps into left ventricle, pumps into rest of body via aorta

Pulmonary System

• Also known as the respiratory system

• Facilitates gas exchange by allowing oxygen into the body and removing CO2

Electrical Pathway

Sinoatrial node -> atria -> atrioventricular node -> bundle of His -> purkinje fibers -> spread electrical impulse through body

White Blood Cells (Leukocytes)

• immunity and defense

• Agranular and Granular