Circulatory Systems

Front 1

Circulatory systems consist of:

Back 1

a pump

a system of tubes

circulatory fluids

Front 2

Purpose of:

a pump

Back 2

(heart)

to provide power in the form of hydrostatic pressure (there may be more than one pump)

Front 3

Purpose of:

a system of tubes

Back 3

(vessels)

through which fluid circulates

open or closed system

Front 4

circulatory fluid

Back 4

(blood)

interstitial fluid or specialized tissue (as in vertebrates)

Front 5

Open circulations

Back 5

blood contained in vessels for only part of its circuit (blood=interstitial fluid)

Front 6

closed circulations

Back 6

blood always remains in vessels

(blood can be different from interstitial fluid); common in active animals

Front 7

blood pressure

Back 7

depends largely on power of the heart

Front 8

what does the flow rate of blood depend on ?

Back 8

blood pressure and resistance to flow

for high flow rates need high pressure and low resistance

Front 9

resistance to flow

Back 9

largely an inverse function of vessel diameter

Front 10

Limiting factor of single circulation (fish)

Back 10

high resistance in gill circuit

low pressure in vessels leading away from gills

low flow rate through systemic circulation

Front 11

How do endothermic birds and mammals support their very high metabolic rates (and needs for lots of circulation)?

Back 11

They evolved a second pump to keep systemic pressure high: a double circulation

(both pulmonary and systemic circuits receive blood at high pressure so flow can be high in both circuits)

Front 12

What provides the force to move blood upward?

Back 12

-veins are buried deep within skeletal muscle

-muscle contraction squeezes veins

-one-way valves force blood to move towards heart

Front 13

total blood flow

Back 13

cardiac output =

heart rate x stroke volume

Front 14

flow adjustments to different body regions

Back 14

blood is selectively routed to whatever organs are active

(muscular valves on arteries, arterioles open or close- vasodilation; vasoconstriction)

Front 15

blood pressure control

Back 15

is a function of cardiac output and vascular resistance (and gravity)

Front 16

erythrocytes

Back 16

red blood cells

transport oxygen with the protein hemoglobin

Front 17

lymphocytes

Back 17

white blood cells

defensive responses

Front 18

thrombocytes

Back 18

platelets

enable the blood to clot in case of injury