ch 18. (cardiovascular s.) Flashcards
What is the pulmonary circuit?
Heart → Lungs → Heart, responsible for gas exchange in the lungs
What is the systemic circuit?
Heart → Body Systems → Heart, distributes oxygenated blood to the body
What is the function of arteries?
Arteries carry blood away from the heart
What is the function of veins?
Veins carry blood to the heart
What is oxygenated blood?
Blood with high O₂ content and low CO₂ content
What is deoxygenated blood?
Blood with low O₂ content and high CO₂ content
What is the function of the pericardium?
Protects and anchors the heart, prevents overfilling with blood
What is the myocardium?
Middle layer of the heart, responsible for contraction
What is the endocardium?
Inner layer of the heart
What is the function of heart valves?
Ensure blood flows in one direction and prevent backflow
What is cardiac output (CO)?
The amount of blood pumped by each ventricle in one minute
What is the formula for cardiac output (CO)?
CO = Heart rate (HR) x Stroke volume (SV)
What is the sinoatrial (SA) node?
The pacemaker of the heart
What is the atrioventricular (AV) node?
Delays impulses
What are Purkinje fibers?
conduct contraction impulse
What are the two main types of heart circulation?
Pulmonary circulation and systemic circulation
What is preload?
degree of elasticity of cardiac muscle cells b4 contraction
What is afterload?
The pressure the ventricles must overcome to eject blood
What is the Frank-Starling law of the heart?
Increased preload leads to increased stroke volume
What are positive inotropic agents?
Substances that increase heart contractility (e.g., epinephrine, calcium)
What are negative inotropic agents?
Substances that decrease heart contractility (e.g., acidosis, calcium channel blockers)
What are positive chronotropic factors?
Factors that increase heart rate (e.g., sympathetic stimulation, epinephrine)
What are negative chronotropic factors?
Factors that decrease heart rate (e.g., parasympathetic stimulation, acetylcholine)
What is the intrinsic conduction system?
sets the heart’s basic rhythm
What is the P wave in an electrocardiogram (ECG)?
Represents atrial depolarization and contraction
What is the QRS complex in an ECG?
Represents ventricular depolarization and contraction
What is the T wave in an ECG?
Represents ventricular repolarization and relaxation
What is stroke volume (SV)?
The volume of blood ejected from a ventricle with each contraction
What is an incompetent valve?
A valve that does not close properly, causing backflow of blood
What is the role of the cardioacceleratory center?
Increases heart rate and force of contraction
What is the role of the cardioinhibitory center?
Decreases heart rate
What is an electrocardiogram (ECG or EKG)?
records electrical activity of heart
What is the difference between systole and diastole?
Systole is the contraction phase; diastole is the relaxation phase
What happens during atrial systole?
The atria contract and push blood into the ventricles
What happens during ventricular diastole?
The ventricles relax and fill with blood from the atria
What is myocardial infarction?
A heart attack
What is angina pectoris?
Chest pain caused by reduced blood flow to the heart muscle
What is fibrillation?
A rapid, irregular heart rhythm
What is defibrillation?
The use of electrical shock to restore normal heart rhythm
What is an aneurysm?
An abnormal bulge in the wall of a blood vessel
What is the role of venous valves?
Prevents backflow of blood
What is the function of erythrocytes (red blood cells)?
Transport oxygen and carbon dioxide in the blood
What are platelets?
Small cell fragments in the blood that help with clotting
What is the difference between arteries and veins?
Arteries ; away from the heart, and veins ; to the heart
What is peripheral resistance?
The resistance of blood vessels to blood flow
What is systolic pressure?
The pressure in the arteries during ventricular contraction
What is diastolic pressure?
The pressure in the arteries when the heart is at rest between beats
What is hypertension?
High blood pressure
What is hypotension?
Low blood pressure
What is blood volume?
amount of blood in the circulatory system
What is the role of baroreceptors?
Detect changes of BP & send signals
What is the renin-angiotensin-aldosterone system?
regulates blood pressure & fluid balance
What is atherosclerosis?
arteries become narrowed due to the buildup of fatty deposits or plaques
What is edema?
Swelling caused by excess fluid in the tissues
What is ischemia?
Reduced blood flow to a tissue
What is heart block?
electrical signals between the atria and ventricles are partially or fully blocked
