Chapter 26: The Heart and Blood Vessels Flashcards
what is the purpose of the circulatory system?
carries digested food carries oxygen aids in the disposal of waste products distributes heat fights disease
what are the two types of circulatory systems?
open circulatory system
closed circulatory system
whats the difference between the two circulatory systems?
open circulatory system consists of open ended blood vessels, this means that the blood exits the vessels and enters the body cells and then returns to the vessels.
closed circulatory system consisted of closed vessels, the blood enters cells through thin walls in the small blood vessels
why is the closed circulatory system more efficient?
blood can be pumped faster around the body - organism is more active
blood flow can be altered
composed of blood, blood vessels and heart
what are the 3 types of blood vessels?
arteries, capilleries, veins
arteries divide into smaller blood vessels, what are they called?
arterioles
veins divide into smaller blood vessels, what are they called?
venules
what is the difference between arteries and veins?
arteries carry blood away from the heart, vein carry blood to the heart.
arteries have thick, muscular walls (high blood pressure here), veins have thin walls (low blood pressure here).
arteries have a pulse, veins do not.
arteries are deep under the skin, veins are near the surface of the skin.
arteries have no valves, veins have valves.
blood in arteries are high in oxygen - except for the pulmonary artery, blood in veins is low in oxygen.
why do arteries have a pulse?
the high blood pressure means the force of blood exerts against the walls of the blood vessels due to the heart contracting, this causes the arteries to expand
why do veins have low blood pressure?
skeletal muscles aid blood circulation, valves control the direction of blood preventing backflow
what are capilleries?
small blood vessels acting as veins and arteries
where are capilleries?
they surround the body cells at the ends of arteries and at the beginning of veins
describe the walls of capilleries
they are only one cell thick, substances can easily get through them and into the blood or out
what does the tricuspid valve do?
prevents backflow into the right atrium
what does the semilunar valve do?
prevents backflow into heart
what does the bicuspid valve do?
prevents backflow into the left atrium
describe bloodflow in the heart.
from the body through the vena cava, into the right atrium, past the tricuspid valve, into the right ventricle, past teh semilunar valve and through the pulmonary artery, into the lungs, from the lungs through the pulmonary vein, into the left atrium, past the bicuspid valve, into the left ventricle, past the semilunar valve and out through the aorta.
what is lung circuit in the circulatory system called?
pulmonary circuit
what is the body circuit in the circulatory system called?
systemic circuit
where does the systemic circuit transport blood?
pumps to the head, trunk, limbs and back to heart
where does the pulmonary circuit transport blood?
pumps to the lungs and back to the hearts