Week 12 part 2 Flashcards
Did you study the heart diagram
Yes
What are the 2 ways a heart can grow?
1) chronic exercise = hypertrophy of heart / cardiac cells = increase in size of cells
2) pathologically (through disease), i.e. hypertrophic cardiomyopathy = left ventricle of heart becomes stiff and thick, and this leads to the heart not being able to pump properly
Where in the blood system does gas exchange occur? What is being exchanged?
In the capillaries. Oxygen goes into the blood, carbon dioxide comes out.
What are the 2 layers of the heart’s membrane (pericardium)?
1) outer fibrous pericardium
2) inner serous pericardium
Where is the pericardial sac located and what is it’s job?
It surrounds the heart on three sides. It has two thin layers of fluid which keeps the heart cool and it reduces friction as the two layers rub against each other when the heart beats.
What are the three layers of the heart (= cardiac muscle), in order of most to least superficial?
1) epicardium
2) myocardium
3) endocardium
What are the two circuits of the heart? What do each do?
- pulmonary circuit = transport blood to lungs
- systemic circuit = transports oxygenated blood to rest of body and brings deoxygenated blood back to heart
What is the job of the myocardium tissue?
To contract the heart, which allows for pumping of blood.
It is in a figure 8 pattern
What kind of tissue is the endocardium? What is its function?
It is a thin layer of connective tissue that lines chambers and covers heart valves.
It prevents blood clotting.
What is the septum of the heart?
It is a wall that divides the heart into chambers.
What is the interatrial septum?
It is a thin wall of tissue that separates the right and left atria (two upper chambers of the heart)
What is the interventricular septum?
Wall of tissue that separates the right and left ventricle
What is a valve? What is its function?
It is like a door that keeps blood from going backwards
What is an AV valve? What is its job?
The valves that separates the atria from the ventricles on each side of the heart. It prevents backflow from the ventricles into the atria
What are chordae tendinae?
They connect flaps of valves to papillary muscles
Which valves are open when the atria contract? Where is the blood going at this time?
AV valves are open, semilunar valves are closed, and blood is going to heart
Which valves are open when the ventricles contract? Where is the blood going at this time?
AV valves are closed and the semilunar valves are open, and the blood is going to lungs and the body.
What are the 3 differences of skeletal muscle vs cardiac muscle?
1) skeletal muscle needs action potential. Cardiac muscle uses autorhythmicity, which makes its own action potential and therefore can contract on its own
2) cardiac muscle uses only oxygen to work
3) cardiac muscle has intercalated disks
What are the two parts that make up intercalated discs (of cardiac muscle)? Describe each one’s purpose.
- gap junctions = directs electrical connection
- desmosomes = allows cardiac cells to act as one big cell, firing together
What is the job of the SA nodes?
It sets the rhythm / pace of your heart by initiating the action potential, which then goes to the atria
What is sinus rhythm? What is an average synus rhythm?
Your normal heartbeat. The average sinus rhythm is 68-72 bpm
What is bradycardia? What is the rhythm of the heart in this condition?
When heart rate is too low. Rhythm is below 60 bpm
What is tachycardia? What is the rhythm of the heart in this condition?
When heart rate is too high. Rhythm is over 100 bpm
When does the first heart sound “lubb” happen?
It happens at the start of a ventricular contraction, and is produced as AV valves close
When does the second heart sound “dupp” happen?
It occurs when semilunar valves close
What is the job of the AV node?
It allows for the signal to pause to let the atria completely empty the blood into the ventricle
What is a systole phase?
Contraction
What is a diastole phase?
Rest phase
Describe the cardiac cycle, starting from what happens in the right atrium to left ventricle.
Atrial systole -> ventricular systole -> atrial diastole
-> ventricular diastole
Explain the standard cardiac cycle in this ECG?
- P wave= contraction / depolarization of atria
- QRS complex = ventricle depolarization / contraction
- T wave = ventricles repolarization / resting
What is the formula to calculate CO (cardiac output)?
CO (cardiac output) = HR (heart rate) x SV (stroke volume)
What is the job of the medulla oblongata?
It regulates heart rate and respiratory system
What makes the sound of the heart (“lub”, “dub”)
Valves closing
