Cardiovascular system
57 flashcards covering Cardiovascular system for the MCAT Biology & Biochemistry section.
The cardiovascular system is your body's network for transporting blood, oxygen, and nutrients to tissues while removing waste products. It consists of the heart, a muscular pump that circulates blood, along with blood vessels like arteries, veins, and capillaries that form a vast delivery system. This system works tirelessly to maintain homeostasis, regulating blood pressure, body temperature, and immune responses, making it essential for overall health and survival.
On the MCAT, the cardiovascular system appears frequently in the Biology and Biochemistry section, often through questions on anatomy, physiology, and pathology. Expect multiple-choice items that test blood flow pathways, heart electrical conduction, or the effects of disorders like hypertension, with common traps including confusing similar structures or misapplying concepts like osmosis in fluid balance. Focus on integrating this system with respiration and the nervous system, as questions may involve experimental data or clinical scenarios.
A concrete tip: Draw diagrams of the cardiac cycle to visualize valve functions.
Terms (57)
- 01
Heart
The muscular organ responsible for pumping blood throughout the body, consisting of four chambers and specialized valves to ensure one-way blood flow.
- 02
Atria
The upper chambers of the heart that receive blood from the veins and pump it into the ventricles, with the right atrium receiving deoxygenated blood and the left receiving oxygenated blood.
- 03
Ventricles
The lower chambers of the heart that receive blood from the atria and pump it out to the body or lungs, with the left ventricle generating higher pressure for systemic circulation.
- 04
Interatrial septum
The wall of tissue that separates the right and left atria, preventing the mixing of oxygenated and deoxygenated blood.
- 05
Interventricular septum
The muscular wall dividing the right and left ventricles, ensuring that blood from the pulmonary and systemic circulations does not mix.
- 06
Aortic valve
The valve between the left ventricle and the aorta that opens during ventricular contraction to allow blood flow into the systemic circulation and closes to prevent backflow.
- 07
Mitral valve
The valve between the left atrium and left ventricle that opens to allow blood from the lungs to enter the ventricle and closes during contraction to prevent backward flow.
- 08
Pulmonary valve
The valve between the right ventricle and the pulmonary artery that opens to send deoxygenated blood to the lungs and closes to maintain forward flow.
- 09
Tricuspid valve
The valve between the right atrium and right ventricle that allows blood from the body to enter the ventricle and prevents its return during contraction.
- 10
Arteries
Blood vessels that carry blood away from the heart, typically with thick, elastic walls to withstand high pressure and transport oxygenated blood, except for the pulmonary artery.
- 11
Veins
Blood vessels that return blood toward the heart, often with thinner walls and valves to prevent backflow, carrying deoxygenated blood except for the pulmonary vein.
- 12
Capillaries
The smallest blood vessels where exchange of gases, nutrients, and wastes occurs between blood and tissues, featuring thin walls for diffusion.
- 13
Systemic circulation
The pathway of blood from the left ventricle through the body tissues and back to the right atrium, delivering oxygen and nutrients while removing wastes.
- 14
Pulmonary circulation
The circuit of blood from the right ventricle to the lungs for oxygenation and back to the left atrium, facilitating gas exchange in the alveoli.
- 15
Cardiac cycle
The sequence of events in one complete heartbeat, including systole when the heart contracts to pump blood and diastole when it relaxes to fill with blood.
- 16
Systole
The phase of the cardiac cycle when the heart muscles contract, ejecting blood from the ventricles into the arteries.
- 17
Diastole
The phase of the cardiac cycle when the heart muscles relax, allowing the chambers to fill with blood from the atria or veins.
- 18
Blood pressure
The force exerted by circulating blood on the walls of blood vessels, primarily measured in arteries and influenced by cardiac output and peripheral resistance.
- 19
Systolic pressure
The higher blood pressure value during heart contraction, representing the force when blood is ejected from the ventricles.
- 20
Diastolic pressure
The lower blood pressure value during heart relaxation, indicating the pressure in arteries when the heart is filling with blood.
- 21
Mean arterial pressure
The average pressure in arteries over a cardiac cycle, calculated as diastolic pressure plus one-third of pulse pressure, reflecting tissue perfusion.
- 22
Pulse pressure
The difference between systolic and diastolic pressure, indicating the force of blood ejected by the heart and the elasticity of arterial walls.
- 23
Cardiac output
The volume of blood the heart pumps per minute, calculated as heart rate multiplied by stroke volume, and a key indicator of cardiovascular function.
- 24
Stroke volume
The amount of blood ejected from the left ventricle per heartbeat, influenced by preload, contractility, and afterload in the heart.
- 25
Heart rate
The number of heartbeats per minute, regulated by the autonomic nervous system and affecting overall cardiac output.
- 26
Frank-Starling law
The principle that the stroke volume of the heart increases in response to an increase in the volume of blood filling the ventricles, up to a limit.
- 27
SA node
The sinoatrial node, the heart's natural pacemaker located in the right atrium, generating electrical impulses to initiate each heartbeat.
- 28
AV node
The atrioventricular node, a delay point in the heart's electrical pathway that slows conduction from the atria to the ventricles for proper filling.
- 29
Bundle of His
A bundle of specialized cardiac muscle fibers that conducts electrical impulses from the AV node to the ventricles for coordinated contraction.
- 30
Purkinje fibers
The network of fibers in the ventricles that rapidly spread electrical impulses to ensure simultaneous contraction of the ventricular walls.
- 31
Electrocardiogram
A recording of the electrical activity of the heart over time, used to diagnose arrhythmias and other cardiac conditions by showing waves like P, QRS, and T.
- 32
P wave
The electrocardiogram wave representing atrial depolarization, the electrical activation that leads to atrial contraction.
- 33
QRS complex
The electrocardiogram waveform indicating ventricular depolarization, marking the electrical signal for ventricular contraction.
- 34
T wave
The electrocardiogram wave that represents ventricular repolarization, the recovery phase after ventricular contraction.
- 35
Autonomic nervous system effects on heart
The autonomic nervous system regulates heart rate and contractility, with sympathetic nerves increasing both and parasympathetic nerves decreasing them.
- 36
Sympathetic effects on heart
Activation of sympathetic nerves releases norepinephrine, increasing heart rate and stroke volume to prepare the body for fight-or-flight responses.
- 37
Parasympathetic effects on heart
Stimulation of the vagus nerve slows heart rate and reduces contractility, promoting rest and digest functions in the body.
- 38
Baroreceptors
Sensory receptors in the walls of blood vessels and the heart that detect changes in blood pressure and help regulate it through reflex adjustments.
- 39
Chemoreceptors
Receptors in the carotid and aortic bodies that sense changes in blood oxygen, carbon dioxide, and pH, influencing heart rate and breathing.
- 40
Renin-angiotensin-aldosterone system
A hormonal pathway that responds to low blood pressure by releasing renin, leading to vasoconstriction and increased sodium retention to raise blood volume.
- 41
Atrial natriuretic peptide
A hormone released by the atria in response to high blood volume, promoting sodium and water excretion to lower blood pressure.
- 42
Vasoconstriction
The narrowing of blood vessels due to smooth muscle contraction, increasing peripheral resistance and blood pressure.
- 43
Vasodilation
The widening of blood vessels through relaxation of smooth muscles, decreasing resistance and allowing more blood flow to tissues.
- 44
Capillary exchange
The process by which substances like oxygen and nutrients diffuse across capillary walls to and from surrounding tissues, driven by pressure gradients.
- 45
Lymphatic system
A network of vessels and nodes that drains excess fluid from tissues, returns it to the blood, and plays a role in immune defense.
- 46
Blood flow equation
Blood flow through a vessel is determined by the formula flow equals pressure difference divided by resistance, based on principles like Ohm's law.
- 47
Vascular resistance
The opposition to blood flow in the vessels, primarily due to vessel diameter, length, and blood viscosity, affecting blood pressure.
- 48
Poiseuille's law
A formula stating that flow rate in a tube is proportional to the fourth power of the radius and inversely to the length and viscosity, explaining resistance in blood vessels.
- 49
Hypertension
A condition of persistently high blood pressure that strains the heart and arteries, increasing risk of heart disease and stroke if untreated.
- 50
Atherosclerosis
The buildup of plaque in artery walls, narrowing the vessels and reducing blood flow, which can lead to heart attacks or strokes.
- 51
Myocardial infarction
The death of heart muscle tissue due to prolonged blockage of coronary arteries, often caused by a blood clot in an atherosclerotic vessel.
- 52
Heart failure
A condition where the heart cannot pump blood effectively to meet the body's needs, resulting from weakened muscle or other cardiac issues.
- 53
Venous return
The flow of blood back to the heart from the veins, influenced by factors like skeletal muscle contraction and respiratory movements.
- 54
Starling forces
The balance of hydrostatic and osmotic pressures across capillary walls that drive fluid movement in and out of capillaries.
- 55
Edema
The accumulation of excess fluid in tissues, often due to imbalances in Starling forces, leading to swelling.
- 56
Strategy for remembering blood flow
To recall the path of blood through the heart, follow the sequence: vena cava to right atrium to right ventricle to lungs to left atrium to left ventricle to aorta.
- 57
Common trap: Arteries vs. veins
A common error is confusing arteries as always carrying oxygenated blood; remember, the pulmonary artery carries deoxygenated blood while the pulmonary vein carries oxygenated blood.