Disease Defences 6.2 Flashcards
From where to where do arteries convey the blood at high pressure?
from the ventricles to the tissues of the body
What do arteries have in their walls?
- muscle cells
- elastic fibers
What do muscle cells and elastic fibers assist?
maintaining blood pressure btw pump cycles
Where do blood flow in the finest stage?
trough tissues of the capillary
What do capillaries do?
allow exchange of materials btw cells in the tissue and the blood
What do veins do?
- collect blood at low pressure from the tissues of the body
- returns it to the atria of the heart
What prevents backflow in veins?
Valves
What type is the lung’s circulation?
separate
Where is the heartbeat initiated?
in the sinoatrial node
What does the sinoatrial node act as?
pacemaker
How does the sinoatrial node send its signal?
through the walls of the atria -> walls of the ventricles
How can the heart rate be reduced of increased?
through two nerves in the medulla of the brain
What chemical increases heart rate?
Epinephrine
Who discovered circulation?
William Harvey
During the cardiac cycle…
pressure changes occur from the left atrium, left ventricle and aorta
What is transported through the blood?
- oxygen
- nutrients
- antibodies
- hormons
- heat
- carbon dioxide
- urea
Plasma
Dissolves or carries all other components of blood, nutrients, wastes