Cardiovascular System Flashcards
What is the Role of the Cardiovascular System?
- Primarily transport for cellular respiration
- Mediated by perfusion of around 40 billion capillaries
- supply cells with oxygen and nutrients
- removes waste e.g. CO2
- heat regulation
- endocrine hormonal transport
- immune function supply
- regulation of blood volume
What is the cardiovascular system composed of?
- Heart
- Pulmonary circulation
- Systemic circulation
Supplies cells with nutrients and oxygen, matches demand output of pulmonary = input of systemic
What is the circulatory system composed of?
- Heart pumps blood through two seperate circulatory systems
- systemic circulation = LH of body
- pulmonary circulation = RH of body
- both systems are interconnected so a problem with blood flow affects the other
- blood always moves in one direction (RH to pulmonary circulation to LH to systemic circulation and back to RH)
Describe the anatomy of the heart?
- Situated obliquely in mediastinum
- anterior, thoracic cavity
- base superior, apex inferior
- left ventricle is thicker than right
What are the 3 layers of the heart?
Pericardium
Myocardium
Endocardium
What is the Pericardium?
- thin, external layer surrounding heart
- double walled membrane sac - parietal and visceral (epicardium) pericardium
Pathology
- pericardial tamponade
- pericarditis
What is the function of the Pericardium?
- prevents displacement of heart
- barrier for infection and inflammation
- lubricant
What is the Myocardium?
- cardiac muscle
- thick middle layer
- left is thicker than the right
- contracts in organised fashion
- damaged during myocardial infarction
What is the function of the Myocardium?
Pumps blood around the body
Describe the Pathology of Myocardium
- Myocardial infarction
- Myocarditis - inflammation infiltrate the heart muscle causing thickening or heart muscle gets dilated - this interferes with filling and pumping
- Myocardial Hypertrophy - develops from long standing HBP, thickened muscle wall makes it difficult for the heart chamber to fill
and muscle contraction become less effective, conduction system runs through muscle layers and gets “messed up” causing rhythm problem
What is the Endocardium?
- Epithelial tissue that lines entire vasculture
- thin layer continuous and endothelium of arteries, veins and capillaries
- Prone to infection as it has direct contact with blood
Describe the Atrioventricular valves
AV prevent entering atria from ventricle during systole
- Tricuspid - right atrium and right ventricle
- Mitral - left atrium and left ventricle
Describe the Semi-lunar valves
Prevents blood entering ventricle from arterial tree during diastole
- Aortic - left ventricle + aorta
- Pulmonary - right ventricle + pulmonary artery
What is Valve Regurgitation?
- blood flows back and forth across valve
- blood flows from the heart reduced
- poor cardiac output
What is valve stenosis?
- blood trying to squeeze through narrow valve opening
- blood flow from the heart reduced
- poor cardiac output
Describe the concept of coronary circulation
- heart requires high O2
- myocardial O2 consumption > skeletal muscle
- increased myocardial metabolic demand equals higher coronary blood flow
- local response and ANS
What are the blood vessels associated with the heart?
- Vessels returning blood to the heart include the superior and inferior vena cava and right and left pulmonary veins
- Vessels conveying blood away from the heart include pulmonary trunk, which split into right and left pulmonary arteries and ascending aorta