circulation Flashcards
what is the function of artery ?
carry blood away from the heart
does arteries carry oxygenated or deoxygenated blood ?
oxygenated
what is the lumen size of arteries ?
small
structure of the artery
thick elastic walls - collagen this is for high pressure
- narrow central tube - lumen and smooth
what has valves in them arteries, capillaries or veins ?
vein
what is the function of the capillaries ?
fine networks of tiny tubes linking arteries and veins
does capillaries carry oxygenated or deoxygenated blood ?
both
what is the lumen size for the capillaries ?
small
what is the structure of the capillaries ?
- consists of endothelium only
- thin outer wall - collagen
- wide central tube
what is the function of the vein ?
carry blood back into the heart
does the veins carry oxygenated or deoxygenated blood ?
deoxygenated
what is the lumen size for the veins ?
big
what is the structure for the veins ?
- thin elastic walls
- narrow central tube
structure of the heart
right : pulmonary artery, vena cava, right atrium, tricuspid, right ventricle, semilunar
left : aorta, pulmonary vein, left atrium, bicuspid valve, left ventricle, semilunar valve
why is the left ventricle wall thicker than the right ventricle wall ?
left ventricle pumps blood for all the parts of the body so needs thicker walls for more work to be done
why does mammals require a double circulatory system ?
manage the pressure of blood flow
why does the blood flow through the lungers at a low pressure ?
prevents damage to the capillaries in the alveoli and also reduces the speed at which the blood flows, enabling more time for gas exchange
why does the oxygenated blood from the lungs then go through the heart to be pumped out at a high pressure to the rest of the body ?
ensure that the blood reaches all the respiring cells in the body
how does a double circularity system differ from a single circulatory system ?
similarities: both contain blood, heart and vessels
differences: heart has 1 or 2 chambers, double circulation has 3 or 4 chambers
is the pressure lower or higher in a single circulation ?
lower
what is the cardiac output ?
the volume of blood that is pushed out of the heart in a given time
equation of the cardiac output ?
cardiac output = stroke volume x heart rate
what is stroke volume ?
the volume of blood pumped out of the heart in one contraction ( heart rate )
equation of the stroke volume
stroke volume = cardiac output / heart rate
Olympic athlete - heart muscle
more heart muscles so stroke volume increases so same cardiac output with fewer beats therefore sufficient supply oxygen allow respiration in cells
what can the cardiac cycle split into ?
atrial systole - contraction
ventricular diastole
ventricular systole - relax
what happens in atrial systole ?
- the atrium muscular will contract, increasing the pressure further - this causes the atria ventricular valves to open and blood to flow into the ventricles
the ventricular muscular walls are relaxed
what happens in diastole ?
the atria and ventricular muscles are relaxed
- this is when blood will enter the atria (vena cava and pulmonary vein)
- the blood flowing into the atria increases the pressure within the atria
what happens in the ventricular systole ?
- after a short delay, the ventricle muscular walls contract increasing the pressure beyond that of the atria - this causes the atria ventricular valves to close and the semi lunar valves to open
- the blood is pushed out of the ventricles into the arteries
coordination of the heart
- Heartbeat begins at sinoatrial node (SAN).
- Depolarisation spreads through the atria, where they contract.
- Atrioventricular nodes (AVN) stimulated by electrical wave. Depolarisation passed into conducting fibres, known as Bundle of His.
- Ventricles contract. Bundle of His splits into two branches, known as Purkinje fibres which carry the wave upwards to the ventricles. This delay enable the ventricles to fill with a sufficient amount of blood before contracting.
role of plasma
to carry substances around the body - hormones, urea and amino acids
role of red blood cells
transport oxygen and nutrients to the lungs and tissues
structure of red blood cells
- biconcave shape - large surface area so greater diffusion
- no nucleus so more haemoglobin
- thin and flexible enabling it to flow through the capillaries
role of white blood cells
lymphocytes - t and b
neutrophils - phagocytes
monocyte
eosinophils - parasitic infection and allergic
basophiles - allergic response
structure of white blood cells
nucleus - controls the release of antibodies
large cells - engulf
receptors - detect pathogens
role of platelets
blood clotting mechanism
structure of platelets
prevents pathogens to enter the body to get infected
role of platelets and plasma proteins - leading to blood clotting
- collagen fibres are exposed - temporary platelet plug - which releases clotting factors like thromboplastin
- vitamin K and calcium ions needed
- prothrombin (protein) changes to its active form thrombin (enzyme)
- soluble fibrinogen forms insoluble fibrin to cover the wound
atherosclerosis - stages
- endothelial damage so fatty deposits build up ( cholesterol circulating in the blood
- they become oxidised so body thinks its pathogen which causes an inflammatory response
- macrophytes to convert into monocytes which engulf the fatty acids
- the cells die and become foam cells than a fibrous cap forms around it —–> atheroma
atherosclerosis - stages when raised blood pressure
- fibrous cap rupture collagen fibers are exposed
- this causes blood clotting leading to myocardial infarction, stroke and aneurysm
what does tissue fluid contain ?
glucose and oxygen which is needed for aerobic respiration
describe how tissue fluid is formed ?
due to hydrostatic pressure substances like glucose oxygen and water are pushed out
explain how tissue fluid is produced and reabsorbed by the capillaries
hydrostatic pressure is generated from left ventricle plasma protein is caused by the oncotic pressure
tissue fluid
high plasma protein - water moves back into the capillary by osmosis - oncotic pressure
what is in the capillary of the tissue fluid ?
red blood cells and plasma protein - to large to exit
if the blood pressure is increases, what happens to the tissue fluid ?
more fluid is forced out - the fluid acculmates in the tissues causing oedema - sign of hypertension
