1 - Introduction to CVS Flashcards
How do single-celled organisms get oxygen and nutrients from their environment?
By diffusion across the cell membrane
Why do large multi-cellular organisms need a cardiovascular system?
For oxygen and nutrients to diffuse, there needs to be a system for these substances to get close to the cells
What is the structure of a capillary?
Single layer of endothelial cells surrounded by basal lamina
What is the function of the cardiovascular system?
- Take oxygen and nutrients to the tissue capillaries so diffusion can take place and pick up carbon dioxide and waste products for excretion
- Cellular signalling via hormones
- Protection of the body from pathogens via the immune system and protection from blood loss via clotting
- Homeostasis of pH, temperature and water balance
Why are coronary vessels required when the heart already contains blood in it’s chambers?
- The distance of cells in the muscle wall from the source of oxygen and nutrients is too large for diffusion to take place
- Only the left side of the heart carries oxygenated blood
Infarcted tissue is caused by a ………. in a coronary vessel. In pathology, the tissue will appear ………….
Blockage
White (scar tissue)
The conorary arteries branch from the ………
Aorta
In the anatomical position, the ……… ………… forms the anterior surface of the heart
Right ventricle
What are the two main branches of the coronary arteries that leave the aorta?
- Right coronary artery
- Left coronary artery
What two branches come off of the left coronary artery?
- Anterior interventricular (left anterior descending)
- Circumflex
Which of the coronary arteries is most commonly blocked in a myocardial infarction?
Anterior interventricular (left anterior descending)
Coronary arteries have few anastomoses, what does this mean?
- They are end arteries and don’t link together very much
- Anastomoses allow blood supply to continue even if one pathway was blocked - coronary arteries cannot do this
Describe the location of the apex of the heart from the surface anatomy.
- 5th intercostal space
- mid-clavicular line
Where is the base of the heart?
- At the superior border, where the great vessels emerge
Where is the right border of the heart, relative to the surface anatomy?
~1cm lateral (right) from the sternum along the 3rd costal cartilage
Where is the right border of the heart, relative to the surface anatomy?
~1cm lateral (right) from the sternum along the 3rd costal cartilage
Where is the right inferior border of the heart, relative to the surface anatomy?
~1cm lateral (right) from the sternum along the 6th costal cartilage
The heart lies within a sac called the ……………
Pericardium
What are the functions of the pericardium?
- Protection for the heart and great vessels
- Lubrication to reduce friction between the heart and the surrounding structures
- Fixed cavity volume prevents overfilling of the heart
- Mesothelial cells lining the pericardial cavity involved in antigen presentation, inflammation and tissue repair, coagulation and fibrinolysis
What are the three layers of the pericardium (outer to inner)?
- Fibrous pericardium
- Parietal pericardium
- Visceral pericardium
The nerves that pass through either side of the pericardium to supply the pericardium and the diaphragm below are the ………… …………
Phrenic nerves
Deeper than the pericardium, what can be found lining the heart?
Epicardial fat
The visceral layer of the pericardium is also called the …………..
Epicardium
The heart muscle layer is called the ……………., the chambers are lined internally with …………..
Myocardium
Endocardium
Where is the transverse pericardial sinus?
Hole created posterior to the ascending aorta and pulmonary trunk (artery)
Where is the oblique sinus?
The hole created by the four Pulmonary Veins and fibrous pericardium, on the Posterior Surface of the heart
The coronary arteries supply the vascular beds of the cardiac muscle, they come together to form the cardiac veins. These drain into the ………… ……….. on the posterior surface of the heart which returns the blood to the ………. ………..
Coronary sinus
Right atrium
How many litres of blood per minute must the cardiovascular system deliver to the body?
Between 5 and 25 litres per minute
How many litres of blood per minute must the cardiovascular system deliver to the brain?
750 ml per minute at all times
Other than the brain, what 2 other organs must have constant blood flow at all times?
- Heart
- Kidneys
The cardiovascular system has capacitance to cope with immediate changes in cardiac output. Where is this store of blood?
In the veins
The heart is ….. pump(s) operating in …………
2, series
What are the four valves of the heart?
- Tricuspid valve
- Pulmonary valve
- Mitral valve
- Aortic valve
Define:
a) diastole
b) systole
a) Diastole - relaxation and filling of the ventricles
b) Systole - contraction and ejection of blood from the ventricles
What types of connective tissue form the fibrous pericardium?
Dense and loose connective tissue
What cell type makes up the parietal and visceral serous pericardium?
Simple squamous epithelium
Where is the phrenic nerve origin?
C3-C5
What is cardiac tamponade?
- Accumulation of fluid, known as pericardial effusion, within the pericardial cavity
- Chambers become compressed due to the pressure, compromising cardiac output
What is pericarditis?
- Inflammation of the pericardium
- Many reasons, including bacterial infection and myocardial infarction
- Chest pain and referred pain (due to compression of phrenic nerve - pain in shoulder)
- Can cause acute cardiac tamponade due to an accumulation of fluid in the pericardial cavity
What is the function of the auricles of the heart?
Atrial appendages – muscular pouch that acts to increase the capacity of the atrium
What muscles are found on the atrial walls?
Pectinate muscles
What is the name of the small oval-shaped depression in the septal wall of the right atrium? What is it’s function?
Fossa ovalis
- Remnant of the foramen ovale in the foetal heart, which allows blood to bypass the lungs
- It closes once the newborn takes its first breath
What is the most common cause of an atrial spetum defect? How is this treated?
Patent foramen ovale after birth
- LA pressure > RA pressure so blood shunts to the right
- Right ventricular overload, leading to pulmonary hypertension, right ventricular hypertrophy and right heart failure
- Treated by surgical closure of the foramen ovale
The muscular elevations in the ventricular wall are called the …………. ………….
trabeculae carnae
The leaflets of the atrioventricular valves are attached to the ventricular wall by …………. muscles and ………….. ……………
Papillary
Chordae tendineae
The outflow portion of the left ventricle is known as the ………. ………….
Aortic vestibule
Tetralogy of Fallot is a congenital heart disease, comprising four abnormalities as a result of a single development defect. What are the four abnormalities?
- Ventricular septal defect
- Overriding aorta (where the aortic valve is positioned directly over the VSD)
- Pulmonary valve stenosis
- Right ventricular hypertrophy
Stenosis of the pulmonary valve increases the force needed to pump blood through it, resulting in right ventricular hypertrophy. The pressure changes result in blood moving from the right ventricle to the left ventricle through the VSD. The position of the aortic valve results in deoxygenated blood entering the aorta.
