The Cardiovascular System Flashcards
Arteries carry blood?
Away from heart (efferent vessels) think exit
The blood is oxygenated
Veins carry blood?
Towards Heart (afferent vessels)
The blood is deoxygenated
What are the 4 chambers of the heart?
- R/L Atria
2. R/L Ventricles
Flow of Blood to the Heart?
- Superior and inferior vena cava
- Right Atrium
- Right AV Valve
- Right Ventricle
- Pulmonary Valve
- Pulmonary Trunk
- Pulmonary Artery
- Pulmonary Vein
- Left Atrium
- Left A.V. Valve
- Left Ventricle
- Aortic Valve
- Ascending Aorta
- Aortic Arch
- Descending Aorta
Location and Size of the heart
Lies In Mediastinum, the middle of the thorax.
Approximate dimensions are 12 cm long, 9cm wide and 6cm deep.
Describe the Pericardium
A loose fitting inextensible sac. Lines the heart. Consist of 2 parts: fibrous and serous portion. Sac is tough white fibrous tissue lines with smooth moist serous membrane.
Trace Coronary Circulation
Ascending Aorta
R Coronary Artery posterior interventricular –> Antrioventricular nodal Artery-> posterior septal Artery
Marginal Artery—>acute marginal Artery
Ascending Aorta
L coronary Artery
Anterior Interventricular branch–> anterior septal Artery
Circumflex branch—> anterior and posterior ventricular branches
Be able to explain what leads to coronary artery disease?
The reduce of blood flow to the vital myocardial tissue.
How does Coronary Artery disease relate to angina and ischemia
The coronary arteries are unable to supply enough blood and oxygen to the heart muscle (myocardium). This can be caused by fatty deposits in the Artery to reduce blood supply.
Be able to describe and/or identify the features and functions of each of the heart’s chambers.
Atria: 2 chambers separated by the interatial septum. Often called receiving chamber because they receive blood from the veins (return Blood to heart) by relaxing and contracting. It also pushes the blood into the lower chambers
Ventricles: 2 lower chambers of the heart separated by interventricular septum. Known as the pumping chamber of the heart because they receive blood from the atria and pump blood out of the heart into the arteries.
Be able to describe the events of the cardiac cycle.
- Atrial Systole:
•begins with P wave of the ECG- triggers atrial contraction
•Contraction of atria creates pressure gradient that pushes blood out of atria into the relaxed ventricles
• Because of gradient AV valves are open; SL valves are closed
• Ventricles are relaxed filling with blood from atria - Isovolumetric venticular contraction-
• onset of ventricular systole coincides with R wave of ECG & appearence of 1st heart sound
• Occurs between start of ventricular systole and opening of SL valves
• Ventricle volume remains constant pressure increases rapidly- intraventricular pressure rises enough to close AV Valve produces 1st heart sound
- pressure is not high enough to open SL valves
- Ejection
• SL valves open and blood is ejected from ventricles when the IV pressure exceeds the pressure in the pulmonary artery and Aorta
• Rapid Ejection- initial short phase characterized by a marked increase in ventricular and aortic pressure and in aortic blood flow
• Reduced ejection: characterized by less abrupt decrease in ventricular volume; coincides with the T wave of the ECG - Isovolumetric ventricular relaxation
• Ventricular diastole begins
• occurs between closure of SL valves and opening of AV valves
• A dramatic fall in intraventricular pressure but not enough to open AV valves, thus no change in volume
•2nd heart sound heard - Passive Ventricle Filling
• continued ventricular relaxation reduces intraventricular pressure and returning venous blood increases intraatrial pressure, produces enough pressure to open AV valves
• blood rushes into relaxing ventricles
• Diastis later longer period of slow ventricular diastole
Define the Cause of S1 and S2
S1: primarily caused by contraction of ventricles and by vibration of closing AV Valves
S2: Vibrations of closing SL valves
Be able to trace an electrical impulse through the conducting system and explain the relationship to the cardiac cycle.
The signal is initiated by SA node (pacemaker) and spreads to the rest of the right atrial myocardium directly, to the left atrial myocardium by way of a bundle of interatrial conducting fibers and AV node by three intermodal bundles. The AV nose then initiates a signal that is conducted through the ventricular myocardium by way of the AV bundle and subendocardial branches (Purkinje Fibers).
Relationship: Heart Beat
SA node→ atrial muscle → AV node→ bundles of His → purkinje fibers → ventricular muscle (contracts from apex to base
- Be able to describe the properties of cardiac action potentials and contrast those properties to skeletal muscle.
- Rapid Depolarization: A) reaches theshold, voltage gates sodium open. B) Influx NA+ C) depolarization
- Plateau: a) membrane potential reaches + 30mv b) Sodium channels close c) Na+ pumped out d) calcium channels open e) calcium pumped in
- Repolarization: a) calcium channels close b) potassium channels open c) potassium rushes out D) negative charge restored
Contrast:
Heart muscles are self excitable and can start there own depolarization
Skeletal Muscle impulses do not spread cell to cell, cardiac muscle functions as a whole unit
Refractory period for cardiac muscle is longer than skeletal. Also cardiac muscle involved the exchange of calcium rather than potassium.
Volume of blood pumped by one Ventricle per minute
Cardiac output
Amount of blood that is ejected from the ventricles of the heart with each beat
Stroke Volume
Be able to describe the influence of the autonomic nervous system on the conduction system and heart rate.
Both divisions of Autonomic Nervous System send fibers to the heart. They increase the heart rate by stimulating the SA Nodes (Pacemaker)
The rate at which the heart beats
Heart Rate
describe end-diastolic volume the factors that influence it
Endiastolic - the amount of blood in ventricles when full
Influenced by preload. Increased increases EDV and Decreased decreases EDV
describe end-systolic volume and the factors that influence it
The amount of blood left behind after Ventricle contracts
Contractility and afterload
Increased contractility decreases ESV, which increases SV
Increased afterload, increases ESV, which decreases SV
How do you calculate cardiac output
CO= HR (Heart Rate) x SV (Stroke Volume)
Causes a Myocardial Infarction
The reduce of blood flow to the vital myocardial tissue. Blood cannot pass through the occluded vessel and so cannot reach the heart muscle cells it normally supplies. Deprived of oxygen they sell soon die or are damaged.
Causes of heart murmur
Incomplete closing of valves or the construction or narrowing(stenosis) of them
Relationship between coronary artery disease, myocardial infarction, and arrhythmia
All have to do with the reduced blood flow to heart
The phase of heart contraction is called
Systole
the phase of relaxation is called .
Diastole
pathway for conduction of an action potential through the heart?
SA node, AV node, AV bundle, bundle branches, Purkinje fibers
Which of the following would increase stroke volume?
Increased Ca2+ in the interstitial fluid, Epinephrine, Increase in venous return
indicates ventricular repolarization
T wave
represents the time from the beginning of ventricular depolarization to the end of ventricular repolarization
Q-T interval
represents atrial depolarization
P wave
represents the time when the ventricular contractile fibers are fully depolarized; occurs during the plateau phase of the action potential
S-T segment