Circulatory System Flashcards
What type of organisms require circulatory systems?
large, complex organisms in which diffusion would be far too slow and inefficient = require bulk flow of nutrients
What type of organisms do not require circulatory systems? what do they use instead?
small, unicellular organisms
or simple organisms
What 5 phyla of animals do not require circulatory systems?
Porifera (sponges)
Cnidaria
Echinodermata
Platyhelminthes (flatworms)
Nematoda
What are the major functions of a CS?
to transport O2 to cells
to remove CO2 and other waste
to transport nutrients
to regulate salts and water
to regulate temperature
to transport signaling molecules (ex. hormones)
for immune responses
What are the 3 major components of a CS?
a pump or propulsive structure
a system of tubes, channels or spaces
a circulatory fluid
What is the function of a pump or propeller?
it generates a pressure gradient to move circulatory fluid around the body
What direction does circulatory flow around the body? why?
unidirectionally because of one way valves in the pump
What are the 3 types of pumps?
chambered hearts
skeletal muscles
pulsating blood vessels
Describe chambered hearts as pumps
hearts have contractile chambers which generate pressure to move fluid into and out of the body
How do skeletal muscles act as pumps?
muscle contraction can squeeze vessels to create pressure and move fluid
how can pulsating blood vessels act as pumps?
peristaltic (rhythmic) contractions of vessel walls move fluid
What are the 2 types fo circulatory fluid?
blood (closed)
hemolymph (open)
What are 3 types of tubes/channels that are used in the CS?
arteries to carry fluid away from heart which branch into arterioles which branch into capillaries
capillaries connect to venules which connect to veins which bring fluid back to the heart
What are capillaries for?
they are very fine, delicate and narrow channels where materials are exchanged between CS fluid and tissues
How does CS fluid flow around the body?
through the vascular system along/down the pressure gradient generated by the pump
what is peristalsis?
rhythmic wave-like contractions of vessel walls
Describe a closed CS (fluid, pumps, vessels, mixing with interstitial fluid, contact with tissues, organism types)
fluid: blood
pump: heart
vessels: blood vessels
no mixing with interstitial fluid
no direct contact with tissues
vertebrates
How are materials exchanged between CS fluid and tissues in closed systems?
through diffusion or transporters in vessels (ex. capillaries)
Describe an open CS (fluid, pumps, vessels, mixing with interstitial fluid, contact with tissues, organism types)
fluid: hemolymph
pump: can be heart
vessels:
sinuses
mixing with interstitial fluid and direct contact with tissues for exchange
invertebrates
What are sinuses? what type of CS are they used in?
they are spaces in the body cavity where CS fluid enters and mixes with interstitial fluid
in open systems
What is interstitial fluid? what type of CS is this in?
the extracellular fluid that surrounds tissues
in both open and closed
What are the 3 major components of blood and their proportion in human blood?
plasma (55%)
erythrocytes (45%)
white blood cells and blood clotting cells (< 1%)
Describe blood plasma
it’s the liquid component of blood
it’s mostly water, but contains some dissolved ions, organic solutes (HCO3) and proteins
What is serum?
blood plasma without the clotting factors