Mass transport in animals Flashcards
1
Q
What is the structure of the heart?
A
- Right atrium, left atrium, right ventricle, left ventricle.
- tricuspid valve , bicupid valve (between atrium and ventricles)
- semilunar valve is between the left ventricle and aorta
- pulmonary artery
- pulmonary veins
- aorta
- superior and inferior vena cava
2
Q
Describe the cardiac cycle?
A
Diastole
- The atria and ventricular muscles are relaxed
- blood enters the atria via the pulmonary veins and the vena cava
- the blood flowing into the atria increases the pressure within the atria
Atrial systole
- The atria muscular walls contracts, increasing the pressure further
- this causes the atrioventricular valves to open and blood to flow into the ventricles
- the ventricular muscular walls are relaxed (ventricular diastole)
Ventricular systole
- after a short delay, the ventricle muscular walls contract, increasing the pressure beyond that of the atria
- this causes the atrioventricular valves to close and the semi-lunar valves to open
- the blood is pushed out of the ventricles into the arteries (pulmonary aorta)
3
Q
Describe diastole?
A
- atria and ventricular muscles relaxed
- blood enters the atria via the pulmonary veins and the vena cava
- blood flowing into the atria slightly increases pressure of the atria
4
Q
Describe atrial systole?
A
- atria contracts increasing the pressure in the atria further, causing the atrioventricular to open
- this causes blood to flow from the atria into the ventricles
- ventricular muscles are relaxed
5
Q
Describe ventricular systole?
A
- after a slight delay, the ventricular muscles contracts, increasing the pressure greater than the atria causing the atrioventricular valves to close
- the semilunar valves open causing blood to be pushed out of the ventricles into the aorta/pulmonary arteries
6
Q
Job of valves in heart?
A
- Ensure one way flow of blood, no backflow
- (blood flows from atria to ventricles to arteries)
- 2 sets of valves: Atrio-ventricular Valve & Semi-lunar Valve
- AV valve = between atria and ventricles
- SL valve = between ventricles and arteries
7
Q
When are AV valves open or closed?
A
- Open = pressure in atria greater then pressure in ventricles,
- Closed = pressure in ventricles greater then pressure in atria
8
Q
When are SL valves open or closed?
A
- Open = pressure in ventricles greater than the pressure in arteries,
- Closed = pressure in arteries greater than the pressure in ventricles
9
Q
Formula for Cardiac Output?
A
- Cardiac output = Stroke Volume x Heart Rate
stroke volume = volume of blood pumped out of the heart in one beat
heart rate = number of beats per minute
Cardiac Output = volume of blood pumped out of the heart in one minute
10
Q
Coronary Heart Disease and Myocardial Infarction?
A
- high blood pressure damages the lining of the coronary artery
- fatty deposits/cholesterol builds up beneath the lining, in the wall = Atheroma
- the atheroma breaks thru the lining forming an Atheromatous Plaque on the lining, in the lumen
- this causes turbulent blood flow
- a blood clot (thrombus) forms
- this block the coronary artery
- therefore less blood flow to the heart muscle
- less glucose and oxygen delivered
- the heart muscle cannot respire
- so it dies (myocardial infarction)
11
Q
Risk Factors of CHD?
A
- Age, gender, ethnicity
- Saturated fats (increases LDL, LDL deposits cholesterol in the arteries to form atheroma)
- Salts (increases blood pressure – lowers water potential of the blood so it holds the water)
- Smoking (nicotine = increase HR and makes platelets more sticky – blood clot, carbon monoxide = permanently blocks haemoglobin)
- Obesity and Lack of Exercise
12
Q
Arteries?
A
- Arteries carry blood away from the heart to the rest of the body
- Their walls are thick and muscular and have elastic tissue to stretch and recoil as the heartbeats, to maintain the high pressure
- the inner lining (endothelium) is folded, allowing the artery to stretch and maintains the high blood pressure
13
Q
Arterioles?
A
.
14
Q
Veins?
A
.
15
Q
Capillaries?
A
.
