Cardiovascular System Flashcards
(31 cards)
What are the functions of the cardiovascular system?
Transports nutrients, gases, hormones, and waste; regulates temperature and homeostasis
Why do large organisms need cardiovascular systems?
Diffusion alone can’t meet metabolic needs; the system ensures efficient nutrient and oxygen transport.
Where is the heart located?
In the thoracic cavity, slightly left of the midline, behind the sternum, in the mediastinum.
What is the pericardium?
A two-layer membrane that protects and anchors the heart and reduces friction
What are the myocardium and endocardium?
Myocardium: cardiac muscle layer. Endocardium: inner lining of heart chambers
What are the four heart chambers?
Left atrium (oxygenated blood from lungs), left ventricle (pumps to body), right atrium (deoxygenated blood from body), right ventricle (pumps to lungs)
Why is the left ventricle thicker?
It pumps blood through the high-pressure systemic circulation.
What do heart valves do?
Ensure one-way blood flow and prevent backflow.
What are the semilunar valves?
Pulmonary and aortic valves; prevent blood backflow into ventricles after contraction.
How does the heart get oxygenated blood?
Through coronary arteries that branch from the aorta.
What is the conduction system of the heart?
Electrical impulses start at the SA node, move to the AV node, bundle of His, bundle branches, and Purkinje fibers.
What does the SA node do?
It is the heart’s pacemaker, initiating electrical impulses for atrial contraction.
Why is there a delay at the AV node?
To allow ventricles to fill with blood before contraction.
What are the bundle of His and Purkinje fibers?
They carry impulses to the ventricles, causing them to contract.
What are desmosomes and gap junctions?
Desmosomes hold cells together, and gap junctions allow electrical impulses to pass between cells.
Why do cardiac cells have many mitochondria?
To provide continuous energy for heart contraction
What are the phases of the cardiac cycle?
Ventricular filling, isovolumetric contraction, ejection, and isovolumetric relaxation.
How long is each phase of the cardiac cycle?
Ventricular filling (0.5s), contraction (0.05s), ejection (0.3s), relaxation (0.08s).
What causes heart sounds?
S1 is caused by AV valve closure, S2 by semilunar valve closure.
What do the components of an ECG represent?
P-wave (atrial depolarization), QRS complex (ventricular depolarization), T-wave (ventricular repolarization)
What is the PR interval?
The time between atrial and ventricular depolarization, indicating AV node delay.
What is the QT interval?
Time for ventricular depolarization and repolarization.
What are the three types of blood vessels?
Arteries (carry oxygenated blood), veins (deoxygenated), capillaries (gas exchange).
What is the structure of capillaries?
Thin walls for efficient exchange of gases and nutrients.
