Biology: Circulatory System Flashcards
How does blood return to the heart?
deoxygenated blood from the venous system reaches the right atrium of the heart from the body via the inferior and superior vena cava
What happens when deoxygenated blood reaches the right atrium of the heart ?
passes through the tricuspid value into the right ventricle of the heart and is then pumped out of the heart via the pulmonary valve via the pulmonary arteries to the lungs
What happens to the oxygenated blood after passes via the lungs?
blood leaves the lungs via the pulmonary veins and reaches the left atrium of the heart, passing through through the bicuspid valve and into the left ventricle before being pumped being pumped out of the heart via the aortic valve
What direction does blood flow through the heart?
from right to left side of the heart
What is the order of the heart valves?
tricuspid
pulmonary
bicuspid
aortic
How is the rate of the heart controlled?
controlled by electrical impulses from the SAN (in RA)
1) Atria contract first
2) ventricles contract (impulse from AVN)
3) the bundle of His
4) purkinje fibres
What are the different aspects of blood pressure?
systolic over diastolic
systole- heart contracts
diastole - heart relaxes
systole + diastole = cardiac cycle
what is cardiac output ?
(ml/min): SV times HR
What is the composition of blood?
55% plasma (90% water + 7% proteins)
45% cells (99% red 1% white)
what are the main functions of blood?
transport oxygen, carbon dioxide, nutrients, waste products, hormones and clotting factors
What are the functions of plasma?
regulates pH, temperature and osmotic pressure
What are the functions of plasma proteins?
for protection
What are the functions of leucocytes?
white blood cells that fight infection
What are lymphocytes?
2 types; helper T cells that mature in the thymes gland and B cells that mature in the bone marrow and produce antibodies that respond to antigens
