12.12 Mass transport in humans Flashcards
Function of the heart
Pump blood around the body
Heart cells
Cardiomyocytes
What does deoxygenated blood return to the heart in?
Vena (vein) into right atrium
Direction of blood flow through heart
Deoxygenated blood return to right atrium via vena
Passes through atria-ventricular valve into right ventricle and out via semi lunar valve into pulmonary artery
Blood passes through the lungs, returns to left atrium via pulmonary vein
Passes through atrio-ventricular valve into left ventricle
Through semi lunar valve into aorta
Function of right atrium
Vena cava brings blood from body
Function of right ventricle
Pulmonary artery takes blood to the lungs
Function of left atrium
Pulmonary vein brings blood from the lungs
Function of left ventricle
Aorta takes blood got body
Pressure definition
The amount of force acting on a surface
Systole definition
Contraction of heart muscle
Diastole definition
Heart muscle relaxed
Cardiac cycle
Arterial systole
Ventricular systole
Diastole
Blood enters atrium
Blood volume increases pressure in atrium
Pressure in atrium greater than ventricle
Atrio ventricular valve opens
Atrium muscles contract
Further increases pressure
Remaining blood forced into ventricle
Blood enters ventricle
Increases pressure in ventricle due to volume of blood
Pressure in ventricle greater than atrium
Atrio ventricular valve closes
Ventricle muscles contract
Further increases pressure in ventricle until greater than aorta
Semi lunar valve opens
Blood enters aorta
Blood is pumped to body (left) or lungs (right)
Ventricle muscles relax
Pressure in ventricle less than aorta
Semi lunar valve closes
Blood enters atrium
Blood volume increases pressure in atrium
What chambers does the blood flow through the heart?
Blood enters atrium
Atrium muscles contract
Blood enters ventricle
Ventricle muscles contract
Blood enters aorta
Ventricle muscles relax
Blood enters atrium
Which heart valves ensure blood flow isn in one direction?
Atrio-ventricular
Semi-lunar
Atrioventricular valves open and closed
Open: Greater pressure in atria than ventricles
Closed:Greater pressure in ventricles than atria
Semi-lunar valves open and closed
Open: Greater pressure in ventricles than arteries
Closed: Greater pressure in arteries than ventricles
What makes sure the valves only open open way?
Tendons that anchor the valves (heartstrings)
Cardiac output equation
CO=SVxHR
Cardiac output = Stroke volume x Heart rate
Stroke volume definition
Volume of blood expelled from the left ventricle in one cardiac cycle
Heart rate definition
Number of cardiac cycles per minute
Cardiac output definition
Volume of blood expelled from the left ventricle per minute
What are the two most common causes of blockage to the coronary arteries?
Atherosclerosis
Thrombosis
What is the deposit of fatty acid in the coronary arteries called?
Atheroma
Risk factors of coronary heart disease
High cholesterol diet
High lipid diet
Smoking
Lack of exercise
Causes:
High blood pressure
Increase in blood toxins
Increase cholesterol levels in the blood
Leads to:
Damage to the endothelium wall
Increase in lipid uptake
Risk factor definition
Any factor which increases a persons chances of developing a disease
What are the risk factors for CHD?
Age
Gender
Genetic factors
Smoking
Stress
High lipid/cholesterol diet
Why is age a CHD risk factor?
Due to a gradual deposit over time
Why is gender a CHD risk factor?
Men are at more risk until middle age, then the risk is similar, due to the protective effect of oestrogen in women up to menopause
Why are genetic factors a CHD risk factor?
Due to genes but also linked to people in the same family have similar lifestyles
Why is smoking a CHD risk factor?
Nicotine is a vasoconstrictor which increases blood pressure, damaging endothelium.
Smoking increases levels of cholesterol in blood
Chemicals in cigarette smoke increases chance of developing thrombosis
Why is stress a CHD risk factor?
Stressful lifestyles increase blood pressure
Why is a high lipid/cholesterol diet a CHD risk factor?
Lipoproteins made in the lover form fats, cholesterol and proteins
Cholesterol transported in the blood to damages areas with LDL
Greater concentration of cholesterol, greater levels of LDL
