Overview
This lecture covers the basic anatomy and key structures of the human heart, as well as the main types of blood cells.
Heart Structure: Chambers, Valves, and Blood Vessels
- The human heart is about the size of your fist.
- The heart has four chambers: right atrium, right ventricle, left atrium, left ventricle.
- Four main blood vessels connect to the heart: superior/inferior vena cava, aorta, pulmonary arteries, pulmonary veins.
- Superior vena cava returns blood from above the heart; inferior vena cava returns blood from below.
- The aorta carries oxygenated blood from the heart to the body.
- Pulmonary arteries take deoxygenated blood from the heart to the lungs.
- Pulmonary veins are unique as the only oxygenated veins; they return blood from the lungs to the heart.
Heart Valves
- The heart contains four major valves to prevent backflow of blood.
- Right atrioventricular valve is between right atrium and ventricle.
- Left atrioventricular valve is between left atrium and ventricle.
- Pulmonary semilunar valve is at the exit of the right ventricle to the pulmonary artery.
- Aortic semilunar valve is at the exit of the left ventricle to the aorta.
Blood Cells: Types and Features
- Red blood cells (RBCs) are biconcave, donut-shaped cells that carry oxygen.
- White blood cells (WBCs) are larger than RBCs and divided into granulocytes and agranulocytes.
- Three granulocytes: neutrophils (most abundant, granules do not stain acid/base), basophils (least abundant, granules stain base), eosinophils (granules stain acid).
- Two agranulocytes: lymphocytes (nucleus fills most of cell, similar size to RBC), monocytes (largest, nucleus is C-shaped, three times the size of RBCs).
Key Terms & Definitions
- Atrium — upper chamber of the heart that receives blood.
- Ventricle — lower chamber of the heart that pumps blood out.
- Aorta — main artery carrying blood from the left ventricle to the body.
- Pulmonary Artery — carries deoxygenated blood from the right ventricle to the lungs.
- Pulmonary Vein — carries oxygenated blood from the lungs to the left atrium.
- Atrioventricular Valve — valve between an atrium and a ventricle.
- Semilunar Valve — valve at the exit of a ventricle.
- Granulocyte — WBC with granules in the cytoplasm (neutrophil, basophil, eosinophil).
- Agranulocyte — WBC without visible granules (lymphocyte, monocyte).
Action Items / Next Steps
- Memorize the names and positions of the four chambers, four valves, and four blood vessels of the heart.
- Review the distinguishing features of the main blood cell types.