Bio 193 circulatory system

Circulatory system

first evolved to transport nutrients, then as respiratory function

“pump”

heart, bulk flow pressure that propels blood thru body

“pipes”

artery, vein, capillary

“fluid”

blood/true blood and lymph, which circulate nutrients and waste.

open circulatory system

less energy required, low pressure (slow), direct diffusion on nutrients/gases into tissues

closed circulatory system

blood confined to vessels, high pressure (fast), more energy required

atria

the two upper chambers of the heart that receive blood from the body and lungs and send to ventricles

ventricles

the two lower chambers of the heart that pump blood out to the body and lungs.

contraction

systole, increasing pressure

relaxed

diastole, decreasing pressure

atrioventricular (AV) valves

separate atrium and ventricles and prevent backflow of blood during contraction.

semi-lunar valves

guard the outlets of the ventricles, preventing backflow of blood into the heart during diastole.

murmur

inefficient blood flow, might go back

serial circulation

one loop, in fish

serial circulation: heart has ____ atrium and ventricle

one

serial circulation: process

heart → gills (O2 exchange) → body tissues→ back to heart

serial circulation limits

low pressure (slow blood flow) low metabolic rate

parallel circulation

parallel heart operates as two pumps (mammals and birds)

parallel circulation: pulmonary circuit

blood is sent to the lungs for O2 exchange

Parallel circulation: systemic circuit

oxygenated blood is sent to the rest of the body

parallel circulation

circuits run in parallel, so heart re pumps blood after lung exchange → high pressure

AV valves

prevents backflow from ventricle to atrium

pulmonary valve/aortic valve

prevent back flow from pulmonary artery to right ventricle and aortic valve to left ventricle

artery

thick muscle, elastic walls, small lumen that carries blood away from the heart.

thin capillaries

lots of SA, low pressure (maximize exchange of blood/interstitial fluid)

veins

small wall, large lumen, low pressure that returns blood towards the heart.

venous blood flow

the movement of deoxygenated blood through veins back to the heart.

venous pressure is ___

low

muscles contract to propel blood thru ____

large veins

valves

ensure blood flow towards the heart

atherosclerosis

the buildup of cholesterol plaques in the arteries, leading to reduced blood flow.

blood composition

red blood cells, white blood cells, platelets, and plasma.

plasma (55%)

carries dissolved gases, nutrients, wastes

erythrocytes (RBC)

contain hemoglobin, which carry O2 to tissues and CO2 away

leukocytes (WBC)

involved in immune response and defense against pathogens.