topic 4.4 - circulation Flashcards
1
Q
structure of arteries
A
- thick walls as they pump blood at high pressures
- elastic fibres
- small lumen
2
Q
function of arteries
A
- carry blood away from heart to cells in body (mostly oxygenated)
- pulmonary artery is the exception where it carries de-oxygenated blood from the heart to lungs
3
Q
what happens in peripheral arteries
A
- the muscle fibres in cell wall either relax or contract to change the size of the lumen, controlling the blood flow
4
Q
structure of capillaries
A
- one cell thick
- thin walls
5
Q
function of capillaries
A
- their structure allows capillaries to fit between individual cells
- allows rapid diffusion of substances between the blood and the cells
- O2 & other molecules diffuses out of blood and waste substances such as CO2 diffuses in
6
Q
structure of veins
A
- thin walls
- large lumen
- few elastic fibres
7
Q
function of veins
A
- carry blood back towards the heart - most carry de-oxygenated blood
- pulmonary veins carry oxygenated blood from lungs to hearts
8
Q
structure of the heart
A
- four chambers - right and left atrium and ventricle
- four main blood vessels - pulmonary vein, pulmonary artery, vena cava & aorta
- atrioventricular valves - tricuspid/bicuspid
- semi lunar valves - pulmonary/aortic
- coronary arteries
- cardiac muscle
9
Q
function of :
- pulmonary vein
- vena cava (superior & inferior)
- aorta
- pulmonary artery
- cardiac muscle
A
- pulmonary vein: from lungs to left atrium
- vena cava: inferior deox blood from lower parts of body to heart and superior carries deox blood from upper part of body. Carried to right atrium
- aorta: from left ventricle to body
- pulmonary artery: right ventricle to lungs
- cardiac muscle: thoicker on left hand side becuase high pressure is needed to pump blood to whole body
10
Q
function of atrioventricular valves
A
prevent the back flow of blood
11
Q
function of pulmonary/aortic valves
A
separate arteries from ventricles
12
Q
function of coronary arteries
A
wrapped around the heart to supply blood to cardiac muscle of the heart
13
Q
what is double circulation
A
- involves two circulatory systems
- systemic circulation carries oxygenated blood from the heart to the cells in the body and carries de oxygenated blood back to the heart
- pulmonary circulation carries de oxygenated blood from heart to lungs where it is oxygenated and carries oxygenated blood back to heart
14
Q
advantages of double circulation
A
- concentration gradient is maintained as oxygenated & de-oxygenated blood don’t mix
- blood pressure to body tissues is higher
- blood pressure to lungs is lower (avoids damaging capillaries in lungs and increases time for gas exchange)
- organisms can develop larger bodies
15
Q
what is a single circulatory system (fish)
A
- heart pumps de-oxygenated blood to gills and becomes oxygenated, giving up CO2 at the same time
- blood travels around the rest of the body, giving up O2 to body cells before returning to the heart
16
Q
stages of the cardiac cycle
A
- atrial systole
- ventricular systole
- cardiac diastole