Biology Lesson #7

The important features in villi

-Increased SA:V

-Thin walls enable easier transport

-Blood vessels for nutrients to absorb and good blood flow

Describe Open circulatory systems

Fluid baths internal organs directly

-Fluid pass through blood vessels → Open haemocoels

-Fluid slowly returns to vessels

-Body bathed carry protein, salt, sugars

-Some invertebrates have a simple tube heart that moves hemolymph through

Describe closed circulatory systems

Circulating fluid is always contained within a set of blood vessels

-Blood pumped by heart through vessels

Describe movement of blood in arteries

o2 rich blood away from heart

Describe movement of blood in veins

o2 depleted blood back to heart

What do capillaries do

Thin wall vessels that connect arteries and veins

Why/how do birds and mammals have the most efficient circulatory systems

-4 chambered heart allows complete separation between o2 rich and poor blood

-Double circulatory system; heart → lungs, heart → body → back

Dis/advantages of open circulatory systems

-Less energy

-Lower blood pressure, blood moves slower

-Less efficient nutrient and waste exchange

Why do some organisms require efficient circulatory systems

Are often endothermic and need consistent temperature

Properties of Arteries

-Carry high pressure blood away from heart

-Carry oxygenated blood (EXCEPT PULMONARY ARTERY)

-Small diameter

-Thick elastic muscular walls

-Expand at high pressure

-No valves

Properties of Capillaries

-Network between artery and veins

-Extremely small diameter, makes red blood cells move single file

-Thin, 1 cell thick wall

-No valves

Properties of veins

-Carries deoxygenated blood towards heart at low pressure

-Except pulmonary veins

-Large diameter

-Thin, flexible walls

-Contains valves

Components of blood

Red blood cells, white blood cells, plasma

Function of red blood cells

transport o2 + co2

function of white blood cells

fights for immune system

function of platelets

clot blood with thread like fibers

function of blood plasma

Solvent to transport substances

Properties of RBC

45% blood volume, no nuclei, short lived, produced in bone marrow, hemoglobin can let 4 o2 molecules bind