Cardiovascular System Flashcards
What is the size of the heart?
Approximately the size of a clenched fist.
Where is the heart located?
Within the inferior mediastinum, between the lungs.
What are the two main layers of the pericardium?
- Fibrous pericardium
- Serous pericardium
What is the function of the fibrous pericardium?
Provides a tough, loose-fitting, and inelastic sac around the heart.
What is the pericardial space?
The space between the parietal and visceral layers of the serous pericardium containing 10-15 ml of pericardial fluid.
What are the three layers of the heart walls?
- Epicardium (visceral pericardium)
- Myocardium
- Endocardium
What is the myocardium?
Thick bundles of cardiac muscle that contract.
What is the role of the endocardium?
A thin layer that lines the heart chambers and is continuous with the linings of vessels.
How many chambers does the heart have?
Four chambers: two atria and two ventricles.
What are the names of the heart valves?
- Atrioventricular valves
- Semilunar valves
What is the tricuspid valve?
The right atrioventricular valve with three cusps.
What is the mitral valve?
The left atrioventricular valve with two cusps, also known as the bicuspid valve.
What is the pulmonary circuit?
Circuit that returns deoxygenated blood to the right side of the heart.
What does the systemic circuit do?
Returns oxygenated blood to the left side of the heart.
What are the components of the coronary circuit?
- Coronary arteries
- Coronary veins
What is aerobic metabolism?
Occurs when O2 is present and is necessary for the metabolic function of the heart.
What is myoglobin’s role in the heart?
Transfers oxygen from the blood to muscle and stores reserve oxygen.
What can occur if a part of the heart is oxygen-deprived for too long?
Myocardial infarction (heart attack).
What does anaerobic respiration provide?
Additional energy for brief periods of oxygen deprivation.
What is the sinoatrial node (SA node)?
The pacemaker of the heart, located in the right atrium.
What is the function of the atrioventricular node (AV node)?
Acts as a pacemaker with a slower rate than the SA node, allowing for optimal filling time for ventricles.
What is the Bundle of His?
Conducts electrical depolarization from the AV node to the ventricles.
What do Purkinje fibres do?
Conduct electrical depolarization into the ventricles, causing contraction.
Fill in the blank: The heart’s intrinsic conduction system sets the basic _______.
[rhythm]
True or False: The myocardium is the outer layer of the heart.
False
What does an Electrocardiogram (ECG) record?
The electrical conduction system of the heart
It represents the depolarisation and repolarisation during the cardiac cycle.
What does the P wave in an ECG represent?
Depolarisation of the atria
What does the QRS complex in an ECG represent?
Depolarisation of the ventricles
What does the T wave in an ECG represent?
Repolarisation of the ventricles
What is a sinus rhythm?
The normal rhythm seen in an ECG
Define Ventricular Tachycardia.
Fast HR of between 120-300 bpm, originating in the ventricles
What is Ventricular Fibrillation?
Chaotic electrical activity with no normal contraction
What is A-systole?
Absence of electrical activity (no pulse)
List the reversible causes of A-systole.
- Hypoxaemia
- Hypovolemia
- Hypothermia / Hyperthermia
- Hypokalemia / Hyperkalemia
- Tamponade
- Tension Pneumothorax
- Toxins / poisons / drugs
- Thrombosis
What is Pulseless Electrical Activity?
Electrical activity is present, but the heart cannot pump blood
What is the function of an Automatic External Defibrillator (AED)?
Delivers a controlled shock to correct arrhythmia
What does the cardiac cycle refer to?
Events of one complete heartbeat
What are the two phases of the cardiac cycle?
- Systole (contraction)
- Diastole (relaxation)
What is Cardiac Output (CO)?
Amount of blood ejected from the left ventricle over one minute
How is Cardiac Output (CO) calculated?
CO = Stroke Volume (SV) x Heart Rate (HR)
What is preload in the context of cardiac function?
Stretch of the wall of the ventricles or filling of blood in the ventricles
What is afterload?
The pressure that the ventricles must build up to open the valves
Define contractility.
Force of contraction of the muscles of the ventricles
What are the two centers that regulate heart rate?
- Cardioacceleratory centre
- Cardio inhibitory centre
What role do baroreceptors play in heart rate regulation?
Detect changes in stretch in major blood vessels
What is the Bainbridge reflex?
Causes HR to increase with increased venous return
What are cardiac cells described as?
Autorhythmic
What neurotransmitter does the parasympathetic nervous system release to decrease heart rate?
Acetylcholine
What are the three layers of blood vessel walls?
- Tunica Intima
- Tunica Media
- Tunica Externa
What is the primary function of arterioles?
Regulate blood flow into the capillaries through vasoconstriction and vasodilation
What is a true capillary?
Branches from arterioles providing exchange between tissue and capillary blood
What is the structural difference between veins and arteries?
Veins are low pressure vessels, thin-walled, and more numerous
What is the skeletal muscle pump?
Contraction of leg muscles compressing deep veins to assist blood flow towards the heart
What are the two circulatory systems in the human body?
Pulmonary and systemic.
What is the function of the right side of the heart?
Pumps blood to the lungs, forming the pulmonary circuit.
What does the left side of the heart do?
Sends blood through the systemic circuit to supply other body cells.
List the components of the pulmonary circuit in order.
- Superior & Inferior Vena Cava
- Right Atria
- Tricuspid valve
- Right ventricle
- Pulmonary semilunar valve
- Pulmonary Artery
- Lungs
- Pulmonary Vein
List the components of the systemic circuit in order.
- Pulmonary Vein
- Left Atria
- Bicuspid Valve
- Left Ventricle
- Aortic Semilunar Valve
- Aorta
- Arteries of each organ
- Arterioles, capillaries, venules, veins of each organ
- Vena Cava
What circulatory system is non-functional in a fetus?
Lungs and digestive system.
How do nutrient and gas exchanges occur in a fetus?
Through the placenta.
What does the umbilical cord contain?
One large vein and two smaller arteries.
What do umbilical veins carry to the fetus?
Blood rich in nutrients and oxygen.
What do umbilical arteries carry from the fetus?
CO2 and debris-laden blood to the placenta.
Fill in the blank: The alternating expansion and recoil of an artery creates a _______.
pulse.
True or False: The radial pulse is the most accessible pulse point.
True.
What is blood pressure?
The pressure the blood exerts against the inner walls of the blood vessels.
Blood pressure is directly related to which two factors?
- Cardiac output
- Peripheral resistance (PR)
What increases peripheral resistance?
- Constriction or narrowing of blood vessels
- Increased blood volume
- Increased blood viscosity
What role do kidneys play in regulating blood pressure?
They alter blood volume and release the enzyme renin when blood pressure is low.
What does renin trigger?
A series of chemical reactions forming angiotensin, a potent vasoconstrictor.
How does epinephrine affect heart rate and blood pressure?
It increases both HR and BP.
What dietary factors can lead to atherosclerosis?
- High salt
- Saturated fats
- Cholesterol
What is hypotension?
Low blood pressure, considered to be a systolic below 100.
Define orthostatic hypotension.
Occurs from standing suddenly from a seated position.
What is chronic hypotension indicative of?
Poor nutrition or inadequate levels of blood proteins.
What does acute hypotension indicate?
A warning of circulatory shock, usually from blood loss.
What is hypertension?
Sustained elevated arterial pressure of 140/90 or higher.
What are the aging changes in the cardiovascular system?
- Replacement of tissues with collagen and fibrous tissue
- Loss of vessel compliance
- Increased left ventricular load
What is pericarditis?
Inflammation of the pericardium causing chest pain and fluid accumulation.
What can cause rheumatic heart disease?
Improper treatment of a streptococcal infection.
What is mitral valve prolapse?
A condition where the mitral valve does not close properly, sometimes related to rheumatic fever.
What is aortic regurgitation?
A leaky aortic semilunar valve causing blood to regurgitate back into the left ventricle.
What results from coronary artery disease?
Reduced blood flow to the myocardium, potentially leading to a myocardial infarction (MI).
Define cardiomyopathy.
A group of diseases resulting in abnormal enlargement of the heart.
What is angina pectoris?
Chest pain due to inadequate oxygen supply to the myocardium.
What is heart failure?
Inability of the heart to pump enough blood to sustain life.
What characterizes congestive heart failure?
Inability of the left ventricle to pump blood effectively, causing fluid retention.
What are the two circulatory systems in the human body?
Pulmonary and systemic.
What is the function of the right side of the heart?
Pumps blood to the lungs, forming the pulmonary circuit.
What does the left side of the heart do?
Sends blood through the systemic circuit to supply other body cells.
List the components of the pulmonary circuit in order.
- Superior & Inferior Vena Cava
- Right Atria
- Tricuspid valve
- Right ventricle
- Pulmonary semilunar valve
- Pulmonary Artery
- Lungs
- Pulmonary Vein
List the components of the systemic circuit in order.
- Pulmonary Vein
- Left Atria
- Bicuspid Valve
- Left Ventricle
- Aortic Semilunar Valve
- Aorta
- Arteries of each organ
- Arterioles, capillaries, venules, veins of each organ
- Vena Cava
What circulatory system is non-functional in a fetus?
Lungs and digestive system.
How do nutrient and gas exchanges occur in a fetus?
Through the placenta.
What does the umbilical cord contain?
One large vein and two smaller arteries.
What do umbilical veins carry to the fetus?
Blood rich in nutrients and oxygen.
What do umbilical arteries carry from the fetus?
CO2 and debris-laden blood to the placenta.
Fill in the blank: The alternating expansion and recoil of an artery creates a _______.
pulse.
True or False: The radial pulse is the most accessible pulse point.
True.
What is blood pressure?
The pressure the blood exerts against the inner walls of the blood vessels.
Blood pressure is directly related to which two factors?
- Cardiac output
- Peripheral resistance (PR)
What increases peripheral resistance?
- Constriction or narrowing of blood vessels
- Increased blood volume
- Increased blood viscosity
What role do kidneys play in regulating blood pressure?
They alter blood volume and release the enzyme renin when blood pressure is low.
What does renin trigger?
A series of chemical reactions forming angiotensin, a potent vasoconstrictor.
How does epinephrine affect heart rate and blood pressure?
It increases both HR and BP.
What dietary factors can lead to atherosclerosis?
- High salt
- Saturated fats
- Cholesterol
What is hypotension?
Low blood pressure, considered to be a systolic below 100.
Define orthostatic hypotension.
Occurs from standing suddenly from a seated position.
What is chronic hypotension indicative of?
Poor nutrition or inadequate levels of blood proteins.
What does acute hypotension indicate?
A warning of circulatory shock, usually from blood loss.
What is hypertension?
Sustained elevated arterial pressure of 140/90 or higher.
What are the aging changes in the cardiovascular system?
- Replacement of tissues with collagen and fibrous tissue
- Loss of vessel compliance
- Increased left ventricular load
What is pericarditis?
Inflammation of the pericardium causing chest pain and fluid accumulation.
What can cause rheumatic heart disease?
Improper treatment of a streptococcal infection.
What is mitral valve prolapse?
A condition where the mitral valve does not close properly, sometimes related to rheumatic fever.
What is aortic regurgitation?
A leaky aortic semilunar valve causing blood to regurgitate back into the left ventricle.
What results from coronary artery disease?
Reduced blood flow to the myocardium, potentially leading to a myocardial infarction (MI).
Define cardiomyopathy.
A group of diseases resulting in abnormal enlargement of the heart.
What is angina pectoris?
Chest pain due to inadequate oxygen supply to the myocardium.
What is heart failure?
Inability of the heart to pump enough blood to sustain life.
What characterizes congestive heart failure?
Inability of the left ventricle to pump blood effectively, causing fluid retention.
