Cardiovascular System Flashcards
How many chambers does the heart have and what are they known as?
4 Chambers:
- 2 atriums: ‘entrances’ where blood is received from circulation
- 2 ventricles: where contraction occurs (valves go upwards & close)
Where is the blood supply from in the left and right…
- Atrium
- Ventricle
Which requires more contraction?
Atrium blood supply:
- Superior Vena Cava (receives blood from above diaphragm)
- Inferior Vena Cava (receives blood from below diaphragm)
Blood in left atrium is from left pulmonary veins (these bring back blood from lungs)
Ventricle blood supply:
- Right ventricle pumps blood up to pulmonary trunk, sends blood to LUNGS
- Left ventricle pumps blood to aorta (largest atery) out to the BODY
Which requires more contraction?
Ventricles (has thick walls for greater contraction, due to higher blood pressure)
(Atrium = thin walls)
Label the main areas of the heart in the order of blood flow.
Hint: specify which side it is on.
- Inferior and superior (above diaphragm) vena cava
- Right atrium
- Tricuspid valve
- Right ventricle
- Pulmonary semi-lunar valve
- Pulmonary artery
- Lungs
- Pulmonary veins
- Left atrium
- Mital valve
- Left ventricle
- Aortic semi lunar valve
- Aorta - main blood supplier - branches off into 2 coronary blood vessels (L & R)
- Body
How many valves are in the heart and what are they subdivided into?
There are 4 valves in the heart
2 atrioventricular valves: between atrium and ventricles
- (R) Tricuspid value - ‘3 cusps’
- (L) Mitral valve - ‘2 cusps’
2 semi-lunar valves: ‘half moon’ cusps
- Aorta
- Pulmonary trunks
Function of the valves in the heart?
To ensure blood flows in one direction
To prevent the backflow of blood
What is an ‘incompetent valve’ or a ‘leaky valve’?
A valve that does not close properly, allowing blood to leak backwards. (The heart can pump the same blood over & over as valve backflows)
A heart can still function unless it is severe
What is valvular sternosis? What is the treatment for this?
When the valves in the heart stiffen, narrowing the valve size meaning they cannot open fully.
As a result the heart has to pump more forcefully and weakens the heart over time.
Treatment: valve to be replaced.
What are the 3 layers of the heart wall?
Epicardium
- Closest to pericardium & most superficial of 3 layers
- Can get infiltrated with fat
Myocardium
- Middle & largest layer
- Contractible layer
- ‘Myo’ = muscle
- Cardium = heart
Endocardium
- Inner, thin layer
- ‘Endo’ = inside
What is the double walled sac that encases the heart?
What are the 2 layers of this sac?
What is its main function?
Pericardium
2 layers:
- Fibrous pericardium: outer layer made of strong connective tissue
- Serous pericardium: inner layer made of serous memberane
What is the pericardial cavity? What is its function?
The space between the two layers of serous pericardium around the heart
Contains small amount of serous fluid that reduces surface tension
Facilitates movement of the heart
What is endocarditis?
Infection of the endocardium caused by bacteria
What is pericarditis?
Inflammation of the pericardium by rubbing against roughened surface of the heart
What is vascular system is known to supply blood to the heart?
Why does the heart require it’s own blood supply?
Coronary circulation: hearts own vascular system that delivers blood to it
Heart requires its own blood supply to obtain oxygen rich blood for survival (aorta branches into 2 coronary arteries)
What is Coronary Heart Disease? How is it caused, diagnosis, treatment & prevention?
What is it also known as?
CHD: When coronary circulation is interrupted by a build up of fatty substances inside your coronary arteries (through a process called atherosclerosis). Arteries become so narrow that it prevents oxygen-rich blood travelling to the heart.
Causes: unhealthy lifestyle (poor diet, no exercise), high cholesterol, high blood pressure, diabetes, smoking, being overweight, family history, age
Diagnosis: ECG, echocardiogram, x-ray
Treatment: Bypass, medication
Also known as:
(CAD) Coronary artery disease
(IHD) Ischaemic heart disease
What is angina? What are the two types of angina?
Angina: The intermittent blocks of arterial circulation that is due to a lack of blood to the myocardium. Referred to as ‘chest pain’
2 Types:
- Stable Angina (more common): Attacks have a particular trigger such as stress or exercising and stops within a few minutes of rest
- Unstable Angina (more serious): Attacks are more unpredictable, may not have a trigger and can continue despite resting
What is Myocardial Infarction?
Myocardial Infarction: tissue death of myocardium caused by prolonged coronary blockage
What is the treatment of a Myocardial Infarction?
CABG - Coronary Artery Bypass Graft
This involves taking a blood vessel from elsewhere in the body and attaching to coronary artery above and below narrowed area
What are the two types of myocardial infarction and what are their differences?
Two types:
- ST Elevated MI:
In a STEMI, there is complete blockage or occultation by the blood clot, and as a result heart muscle being supplied by the affected starts to die.
This type of heart attack is more severe. It is usually recognized by ECG.
ECG shows that the “ST-Segment” portion is highly elevated. The elevated ST-Segment indicates a large amount of heart muscle damage.
- Non-STEMI:
In an NSTEMI, the artery partially or partly occludes and as a result, only a portion of the heart muscle being supplied blood by the affected artery dies. In Non-STEMI, does not elevate ST segment in ECG.
**insert photo
What are the causes of Myocardial Infarction?
Embolisms or thrombosis High level of blood cholesterol Obesity Smoking Short time exposure to air pollution Emotional stress Genetic Men are more at risk than women Use of combined oral contraceptive pills
How is a cardiac arrest different from myocardial infarction?
Myocardial Infarction results from the INTERRUPTION of the blood supply to the myocardium (resulting from narrowing of the coronary arteries due to atherosclerosis)
Cardiac arrest however is the CESSATION of the blood circulation due to failure of the heart to contract
What is an ECG and what does it stand for?
ECG - Electrocardiogram
A non-invasive method of measuring heart’s rhythmic and electric activity, by placing metal electrodes on the chest. The results are measured as waves on a graph in response to each stage of the heartbeat
Interpret this ECG graph
**insert photo of ECG graph
What do the initials CABG stand for?
Coronary Artery Bypass Graft (surgery)
When do veins not carry deoxygenated blood & explain why?
When in pulmonary veins
As the blood in it has not been yet oxygenated by the lungs
What are the lungs most responsible for, in relation to what the blood takes & unloads?
Lungs are most responsible for:
- Unloading CO2
- Picking up O2
(Gaseous Exchange)
The heart is 2 pumps, the left and right side of the heart.
What circuits/where do the left and right sides of the heart receive blood from?
RIGHT side: Receives blood through systemic circuit.
Lungs -> Heart -> Body
LEFT side: Receives blood through pulmonary circuit.
(o2 poor blood)
Body -> Heart -> Lungs
*** INSERT PHOTO
Explain blood flow to the heart - in terms of circuits involved.
Pulmonary Circuit:
- Capillary beds of lungs allows for blood to pick up o2 and drop Co2 (gaseous exchange)
- Oxygenated blood travels down pulmonary veins
- Enters left atrium, left ventricle, through to aorta and branches
- Oxygenated blood sent to the capillary beds of all body tissue where o2 is distributed out to the body, meaning blood is left o2 poor (deoxygenated)
Systemic circuit:
- Body takes up all oxygen, so deoxygenated blood is sent to the heart (through superior and inferior vena cava)
- Through right atrium, right ventricle, out through pulmonary trunk
- Pulmonary arteries carry blood to the lungs where o2 picked up and co2 dropped (gaseous exchange)
What is the cardiac muscle and where is it found?
Cardiac is 1 of 3 muscles found in the body (found in the heart)
It is found in the middle layer of the heart the ‘myocardium’
Myo=muscle
Why does the heart contract?
To allow blood to be pumped with high contractile strength around the blood to take up oxygen
(SA) To ensure blood is pumped at a rhythmic rate
Explain why the heart is involuntary and striated?
‘Striated’ as cytoplasm contains myofibrils and sarcoplasm and exhibits a ‘striated’ appearance.
Involuntary as it cannot be controlled on demand, the pacemaker (SA node) ensures continual pumping of heart
What is the conducting system of the heart and what does it consist of?
Clue: specialised
A group of specialised cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract
Consists of:
- SA (sinal atrial) node
- AV (Atrioventricular) node
- Bundle of His (AV bundle)
- Conducting fibers
- Purkinje fibers
What does the conducting system of the heart provide the heart with?
Regular, rhythmic heart beats (from SA node ‘pacemaker’)
Beats independent of nervous & hormone control
What system modifies and supplies the conducting system?
Clue: begins with A
Autonomic nervous system (ANS)
Supplied by: parasympathetic and sympathetic nerve fibres, to raise or lower heart rate
