Topic 9 (circulatory system) Flashcards
What is transport like in simple unicellular organism?
Oxygen, nutrients and waste products diffuse easily
through the cell membrane of a simple unicellular
organism.
What is transport like in complex multicellular organisms?
Transport system in mammals consists of:
* Blood vessels
* Blood
* Heart
* Valves
What is the main transport system in humans?
The main transport system
in humans is the circulatory system.
What are the main components of blood?
*Plasma
*Red blood cells
*White blood cells
*Platelets
What are the main functions of each component?
*Plasma: The liquid portion of the blood which contains water, salts and enzymes.
*Red blood cells: Red blood cells transport the oxygen required for aerobic respiration in body cells.
*White blood cells: White blood cells are cells that help to fight infections and diseases.
*Platelets: Cells that help to prevent bleeding by forming clots.
What are the components of the circulatory system?
*Arteries
*Veins
How are substances transferred between capillaries and tissue cells?
Arteries:-
Structure:
Have thick muscular walls with
much elastic tissue.
Have small lumen relative to
diameter.
Semilunar valves absent.
Function:
Carry blood away from the heart.
Carry oxygenated blood (except
for pulmonary arteries which carry
deoxygenated blood from the heart
to the lungs).
Flow:
Blood under high pressure.
Blood moves in pulses, reflecting
the rhythmic, pumping action of
the heart.
Blood flows rapidly.
How are substances transferred between capillaries and tissue cells?
Veins:-
Structure:
Have thin muscular walls with little
elastic tissue.
Have large lumen relative to
diameter.
Semilunar valves present.
Function:
Carry blood towards the heart.
Carry deoxygenated blood (except
for the pulmonary veins which
carry oxygenated blood from the
lungs to the heart).
Flow:
Blood under low pressure.
No pulse.
Blood flows slowly.
How are substances transferred between capillaries and tissue cells?
Capillaries:-
Structure:
Have one-cell thick walls with no
muscular or elastic tissue.
Have large lumen relative to
diameter.
Semilunar valves absent.
Function:
Link arteries to veins.
Blood changes from oxygenated at
the arteriole end to deoxygenated
at the venule end.
Flow:
Pressure of blood reduces as
blood flows from arteriole to venule
end.
No pulse.
Blood flows slowly.
What is double circulation?
In mammals, blood flows through the heart twice during each circuit of the body 🡪 double circulation.
Double circulation in mammals consists of the pulmonary circulation & the systemic circulation.
What’s the difference between pulmonary circulation & systematic circulation?
Pulmonary circulation:
Links the lungs to the heart.
Systematic circulation:
Circulates blood around the body
State the advantages of double circulation.
- Blood flows more slowly
through the lungs, allowing
sufficient time for it to be well
oxygenated. - Four-chambered heart
ensures separation of
oxygenated blood from
deoxygenated blood. - Oxygenated blood is
distributed to the body tissues
more quickly.
Structure of the heart.
Right atrium: collect deoxygenated blood & pump it to right ventricle
Right ventricle: pumps deoxygenated blood to lungs Pulmonary artery: carries deoxygenated blood from right ventricle to lungs
Septum: separates left and right sides of the heart Pulmonary vein: carry oxygenated blood from lungs to left atrium
Left atrium: collect oxygenated blood and pump it to left ventricle
Left ventricle: pumps oxygenated blood to the body via the aorta
Aorta: carries oxygenated blood from left ventricle to rest of body
Tricuspid and bicuspid valves: prevent backflow of blood into the atria when ventricles contract (atria ventricular valves)
Pulmonary and aortic valves: prevent backflow of blood from the arteries into the ventricles (semi-lunar valves)
Memorize heart circulation and structure!!!
What is blood pressure?
Blood pressure is the force of the blood exerted on
the walls of the blood vessels.
