Cardiovascular Physiology Flashcards
What is the key purpose of the cardiovascular system?
To transport -
- Nutrients
- Oxygen
- Waste products
- Heat
- Hormones
- Immune cells
What is the name of cardiac muscle cells and what is a quality of them?
- Cardiomyocytes
- Electrically excitable
Describe the basic structure of the heart
- Split into 4 chambers with atrium on top
- Facilitates double pump
- Right side for pulmonary circulation and left side for systemic circulation
Describe the 2 main events of the cardiac cycle
- Diastole - relaxation and the chamber filling with blood
- Systole - contraction and ejection of blood out of the chamber
Outline the cycle of pulmonary circulation in the cardiac cycle in order
- Deoxygenated blood from the body
- Superior vena cava
- Inferior vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary valve
- Pulmonary artery
- Lungs
Outline the cycle of systemic circulation in the cardiac cycle in order
- Oxygenated blood from the lungs
- Pulmonary veins
- Left atrium
- Mitral valve
- Left ventricle
- Aortic valve
- Aorta
- Arteries in the body
Outline the process of cardiac conduction
- Transfer of action potentials
- Contraction of cardiomyocytes
- Pressure within chambers
- Movement of blood
What happens simply during depolarisation and repolarisation?
- Depolarisation - contraction of cardiomyocytes
- Repolarisation - relaxation of cardiomyocytes (ready to contract again)
Describe the process of atrial depolarisation/P wave
- Movement of impulses around atria result in the first observable deflection (P wave)
- Contraction of the cardiac muscle cells in the atria
- Contraction of the atria leads to movement of blood into the ventricles
Describe ventricular depolarisation
- Impulses around the ventricles result in the next observable deflections = QRS complex
- Contraction of the cardiac muscle cells in the ventricles
- Contraction of the ventricles leads to movement of blood into the major arteries (systemic and pulmonary)
Describe the process of repolarisation
- Repolarisation of the ventricles is the last observable deflection = T wave
- Cardiac muscle cells relax before next contraction
- Allows resetting (repolarising) of membrane potential
Briefly describe arteries, veins and capillaries
- Arteries - high pressure, distribution of oxygenated blood back to cells
- Veins - low pressure, return of deoxygenated blood back to the heart
- Capillaries - exchange vessels
Outline the structure of arteries and veins
- Arteries - thicker tissue, more elastic, withstand high pressure
- Veins - have valves, larger lumen
What are the purposes of blood?
- Transport of oxygen, carbon dioxide, glucose and hormones
- Regulation of pH and temperature
- Protection of disease and blood loss
What are the components of blood and what is the total blood volume?
- 55% plasma
- 44% RBCs (haematocrit)
- 1% WBCs and platelets
- 5-6L in males, 4-5 in females
What is the formula for cardiac output and the unit?
Cardiac output (L/min) = heart rate x stroke volume
Describe the endocrine factors involved with cardiovascular regulation
- Epinephrine (adrenaline) - increases HR and heart contractibility
- Norepinephrine (noradrenaline) - blood pressure regulation
- Nitric oxide - vasodilation
What is the formula for blood pressure?
Blood pressure = vascular resistance x cardiac output
How does cardiac output differ between athletes and non athletes?
- Similar cardiac output at rest (5L/min)
- Drastic
What is the effect on the heart for athletes?/cardiac remdelling
- Cardiac hypertrophy in the left ventricle
- Chamber dilation
- Resting cardiac output is maintained despite a reduced heart rate
