Circulatory system

what is the purpose of the circulatory system?

transport gasses, nutrient molecules, hormones and wastes, regulate internal temp, protext against blood loss, disease, toxins

What are the components of the circulatory system?

heart, blood vessels, blood

heart

muscular organ that pumps blood through the body

blood vessles

system of hollow tubes through whch blood moves

blood

fluid that transports nutrients, oxygen, carbon dioxide

How many types of circ systems are there?

2 (open and closed)

Open circ system

circulatory system where blood flows freely within the boy cavity and makes direct contact with organs and tissues

What is osmosis?

insects, crustaceans

Closed Circ system

circulatory system where blood is kept contained within vessels, materials must pass through vessel wall to get to organs

what organisms have a closed circ system?

earthworms, birds, humans

Requirements of circ system

oxygen, food nutrients, water

Plasma

most water, dissolved in molecules and ions, maintains PH balance. proteins include antibodies and blood clotting

Red blood cells

Hemoglobin in RBC carry oxygen, mae in the bone marrow. dead RBC are broken down by the liver, biconcave discshaped cells

why are RBC shaped that way?

Maximise SA --> Maximized function

Anemia

Occurs when there is a shortage of hemoglobin

What causes anemia

too few RBC's, too little hemoglobin (iron deficiency)

what are the symptoms of anemia?

weakness, fatigue, headaches

Treatment for anemia?

dietary change, iron supplements, vitamin B12 supplements, blood transfusions

White blood cells

protect against infection, destroy bacteria or produce antibodies, found in circ and lymphatic system

Platelets

fragments of cells and function in the blood in clotting

Arteries

carry blood away from the heart at high pressure, toward the body tissues and therefore carry oxygen rich blood

what is the exception to arteries

pulmonary artery carries oxygen poor blood to the lungs

what are the walls like for artieries?

think and highly elastic walls in order to withstand high pressure as ventricles contract

where do arteries tend to be in your body?

buried deep within your body for protection

Movement from arteries to cappilaries

Arteries branch to smaller vessels called arterioles capillaries

capillaries

very thin (1 cell think), function is to exchange materials between blood and body tissues

How do gasses exchange through capillaries

oxygen and carbon dioxide diffuse across the walls of capillaries

What are capillaries collected into?

venules (smaller than veins)

veins

carry blood back to the heart at low pressure

what must the low pressure in veins overcome?

gravity

Compared to arteries, what are veins larger in?

larger in diameter because they are thin walled

What do veins rely on for movement of blood?

not as elastic as arteries, so they rely on muscle contraction to move blood towards heart

function of valves

prevent backflow of blood (allow for blood to flow in one direction TOWARDS the heart)

Muscle Action

skeletal muscle activity in the surrounding muscle helps squeeze the veins

Breathing action

creates a negative pressure in the chest, which sucks the blood into the heart up into the heart