CVS Overview Flashcards
What is the circulatory system?
Organ system transporting oxygen, carbon dioxide, nutrients, etc
What is the cardiovascular system?
Heart, blood vessels (arteries, veins and capillaries), blood, lymphatic system
What are the 2 “loops” of circulation?
- Pulmonary circulation
2. Systemic circulation
Describe the pulmonary circulation
- Oxygen depleted blood
- Passes from heart to lungs
- Returns oxygenated blood to heart
Describe the systemic circulation
- Oxygen rich blood
- Passes from heart to rest of body
- Returns deoxygenated blood to heart
What are the boundaries of the superior mediastinum?
T1 and sternal angle (rib number 2)
Which part of the body is used as a reference for CPR?
Middle mediastinum
What is the pericardium?
Outermost fibrous layer protecting the heart - consists of 2 layers (visceral and parietal layers)
The pericardium provides an anchor - holds everything in place
What is between the visceral and parietal pericardium?
Serous fluid
What is the purpose of serous fluid between the viscera land parietal pericardium layerS?
Minimises friction each time the heart beats
What is myocardium?
Heart muscle - forms the bulk of the heart
What is a myocardial infarction?
A heart attack
What does the superior vena cava drain?
Everything above the level of the heart
What does the inferior vena cava drain?
Everything below the level of the heart
Why does the pulmonary trunk divide in two?
One artery for left lung, one artery for right lung
Which arteries carry deoxygenated blood?
Pulmonary arteries
Where is the apex of the heart located?
At the bottom of the heart
Where does the umbilical vein go?
Goes into the baby’s heart from the mother’s placenta
Carries oxygenated blood
What is the function of the ductus venousus in foetal circulation?
Allows oxygenated blood from the umbilical vein to bypass the liver
Oxygenated blood from the umbilical vein is shunted directly to the inferior vena cava
What is the name of the hole between the atria in developing babies?
Foramen ovale
What is the purpose of the foramen ovale?
Shunts oxygenated blood from right to left atria
Allows oxygenated blood coming from the umbilical vein via the inferior vena cava to bypass the pulmonary circulation
Lungs don’t work until ~35 weeks
What happens to the foramen ovale when a baby is born?
Once the umbilical cord is cut, the foramen ovale shuts instantly.
What is the ductus arteriosus?
Allows blood from right ventricle to bypass the lungs
Allows blood to pass straight from pulmonary trunk to the aorta
What is the purpose of the 3 shunts in foetal circulation?
Ductus venous: shunts blood away from liver
Ductus artists and foramen ovale: allows blood to bypass the lungs (non-functioning)
What happens if coronary arteries are blocked?
Heart attack
Which arteries are termed ‘end arteries’ to the heart?
Coronary arteries
What is the foramen ovals called when it shuts?
Fossa ovalis
What drains the heart?
Orifice of coronary sinus
What do musculi pectinati do?
Cause turbulence
Increase the flow of blood/help to propel blood
What are chordae tendinae?
Heart strings - tough, tendinous strands attached to papillary muscles
What is the purpose of chordae tendinae?
Hold the atrioventricular valves (bicuspid and tricuspid) in place when pumping blood - ensures blood doesn’t flow in the opposite direction
Which ventricle supplies the lungs?
Right ventricle
Which ventricle has a thicker wall and why?
Left ventricle = thicker wall
Because the left ventricle supplies the systemic circuit - requires more force to pump blood round the body
What are septal defects?
Holes in the heart
What are the 3 types of septal defect that can occur?
- Atrial septal defect (foramen ovale may not close properly)
- Ventricular septal defect (ductus arteriosus may not close properly)
- Atrioventricular septal defect
What are the 3 types of septal defect that can occur?
- Atrial septal defect (foramen ovale may not close properly)
- Ventricular septal defect
- Atrioventricular septal defect
What do the heart sounds “lub” and “dub” correspond to?
“lub”: loud noise due to closure of the AV valves at time of atrial systole
“dub”: soften sound due to closure of the semilunar valves at the time of ventricular systole
Which valves have chordae tendinae?
AV valves - semilunar valves (aortic and pulmonary valves) don’t have chordae tendinae
What is the right AV valve called?
Tricuspid valve
What is the left AV valve called?
Bicuspid/mitral valve
What is the purpose of the valves in the heart?
Prevent the back flow of blood
What is infective endocarditis?
Infection of the endocardium usually by bacteria (e.g. strep viridians, staph aureus)
Most common is subacute bacterial endocarditis (SBE)
What is infective endocarditis?
Infection of the endocardium usually by bacteria (e.g. strep viridians, staph aureus)
Most common is subacute bacterial endocarditis (SBE)
Occurs on rheumatic or congenitally abnormal valves
Can also affect prosthetic valves
May present as a murmur
Which dental problem can cause infective endocarditis?
Dental abscess
What is ischaemia?
Reduced oxygen supply to tissue
Can result in collateral circulation developing (alternate circulate around a blocked artery or vein)
What is angina pectoris?
Chest pain related to coronary artery disease (CAD)
What is a CABG?
Coronary artery bypass graft
Reattach veins to act as arteries
What are the components of the conducting system of the heart?
Right atrium, atrioventricular node, atrioventricular bundle, Purkinje fibres
What is atrial fibrillation?
Rapid, irregular contraction of different parts of the atria
What is ventricular fibrillation?
- Rapid, irregular contraction fo the ventricles
- Not compatible with systemic and pulmonary circulation
- This is the most disorganised form of cardiac arrhythmia, and leads to cardiac arrest
What are the 3 layers of the arterial wall?
Tunica intima
Tunica media
Tunica adventitia
What effect does systole have on arterial walls?
Causes expansion of arterial walls
What is arterial blood pressure maintained by during diatole?
Recoil
How is blood flow regulated arteries?
Varying diameter of the capillaries
What are 3 types of arteries?
- Muscular arteries: radial, femoral, coronary and cerebral arteries
- Elastic arteries: Aorta, common carotid, subclavian and pulmonary arteries
- Arterioles: terminal branches supplying capillary bed
