Lab 5: The Heart and Blood PDF

# LAB 5! - The Heart and Blood ## The Heart - Four chambered organ that pumps blood to the body; in the mediastinum of thoracic cavity - **Right side:** receives deoxygenated blood from systemic circulation & pumps this blood to lungs to receive oxygen - **Left side:** receives oxygenated...

# LAB 5! - The Heart and Blood ## The Heart - Four chambered organ that pumps blood to the body; in the mediastinum of thoracic cavity - **Right side:** receives deoxygenated blood from systemic circulation & pumps this blood to lungs to receive oxygen - **Left side:** receives oxygenated blood from lungs & pumps this blood to the rest of the body ## Pericardium - Composed of fibrous & Serous pericardium - **Fibrous pericardium:** the sac or bag the heart sits in - **Serous pericardium:** a thin membrane immediately deep to fibrous pericardium - **Parietal pericardium:** more superficial & attached to the inner layer of fibrous pericardium - **Visceral pericardium:** commonly called epicardium - **Serous Fluid**: between parietal & visceral layers; produced by these layers to help decrease friction around the heart ## Chambers - **Atrium:** upper chamber; receive blood from the body (right side from Systemic & left side from pulmonary) - **Ventricle:** lower chamber; blood from atria flow into ventricles which will contract & push blood out into body (right ventricle to lungs & left to rest of body) - **Interventicular Septum:** ventricles divided by large wall of heart muscle (myocardium) ## Three Layers of Heart Wall 1. **Epicardium:** most superficial layer & is the visceral layer of serous pericardium; simple squamous epithelium directly attached to the exterior surface of heart 2. **Myocardium:** muscular portion of heart wall; responsible for contraction of heart: pumping blood into vascular system 3. **Endocardium:** deepest layer; simple squamous endothelium which lines the interior of heart & continuous & all blood vessels ## Anatomical Position - **Base of heart:** flattened superior portion where you would see blood vessels emerging from the heart - **Apex:** inferior and points to the left in anatomical position - **Auricle:** each atrium has a muscular auricle which sits atop the atria; helps increase the volume of the atria to accept blood from the vascular system - **Anterior Interventricular Sulcus:** anterior surface of heart - **Posterior Interventricular Sulcus:** posterior surface of heart - **Left /Right Atrioventricular Sulci**: divide atria & ventricles; house various coronary blood vessels ## Blood Vessels - **Superior Vena Cava:** enters the right atrium from the top & returns blood to the heart from the head, neck, upper extremities - **Inferior Vena Cava:** enters the atrium from the bottom & returns blood from the abdomen & lower extremities - **Coronary Sinus:** opening of right atrium which returns deoxygenated blood from coronary circulation - **Pectinate Muscle:** muscular ridges beneath the auricle of internal atrial wall ## Valves - **Atrioventricular Valve (AV Valve):** between each atrium & ventricle; blood flows through to get to each ventricle - **Tricuspid Valve:** between right atrium & right ventricle; three cusps composed of endocardium - **Bicuspid (Mitral) Valve:** between left atrium & left ventricle; has two cusps - **Chordae Tendineae:** small tendon cords anchored to ventricles via papillary muscles - **Papillary Muscles:** contract when blood is being forced out of the ventricles which causes Chordae Tendineae to pull the cusps of AV valves closed - **Trabeculae Carnae:** ridges on wall of ventricle; more visible in left than right ventricle ## Semilunar Valves (SL) - Blood leaving ventricles must pass through ; prevent backflow from vessels into ventricles - **Pulmonary Semilunar Value:** between right ventricle & pulmonary trunk; three cusps - **Aortic Semilunar Value:** between left ventricle and aorta; three cusps ## Fetal Circulation - Blood is mostly diverted away from the lungs - **Foramen Ovale:** hole in interatrial septum; allows blood to pass from right to left atrium - **Ductus Arteriosus:** blood from pulmonary trunk shunted to aorta via ductus arteriosus - **At birth, both structures close over and become fossa ovalis & ligamentum arteriosum** ## Gross Anatomy and Histology of Cardiovascular System -Image of heart: left and right atrium and ventricle labeled. -Labels: **Left and Right Atrium and Ventricle, Pulmonary Trunk, Pulmonary Arteries and Veins, Aorta, Superior and Inferior Vena Cava, Brachiocephalic artery**, and **interventicular septum** # LAB 5! - Tissues ## Cardiac Muscle Tissue - **Contractile** and **excitable** - Branched with one nucleus - Numerous mitochondria due to high energy demands for beating heart - **Intercalated Disks:** - Folded plasma membrane where two cardiac muscle cells meet. - Link cells structurally and functionally. - **Gap Junctions:** - Areas of low electrical resistance that allow ions to pass easily between cells for communication. - **Desmosomes:** - Adhesive junctions holding cells tightly together. ## Blood - Connective tissue consisting primarily of cells & cell fragments suspended in a liquid extracellular matrix (plasma) - Fibres: most readily visible during the clotting process - **Hemopoiesis:** blood cell production; all blood cells originate from pluripotent stem cells found in red bone marrow of adults. ## Red Blood Cells - **Erythrocytes**: make up the bulk of cellular components of blood; biconcave & lack nuclei - **Hemoglobin:** molecule consisting of protein globin & heme which contains iron - **globin:** four polypeptide chains, each containing a heme in the centre - **heme:** iron is binding site for oxygen; amount of oxygen determines shade of red; when all 4 heme have oxygen binded = bright red ## White Blood Cells - **Leukocytes**: larger than erythrocytes & dark staining nuclei vary in shape; they keep body free of invaders - **Neutrophils:** lobed nuclei & relative abundance; heavily involved in phagocytosis - **Lymphocytes:** attack invaders directly or produces antibodies which attach to antigen & neutralize or destroy it ## Platelets - **Smallest**: cell fragment of precursor cell that consists of a cell membrane enclosing the cytoplasm with no nucleus - **Platelet Plug:** Formed from fragments & release factors that assist in clotting. - Image of Cardiac Muscle Tissue: shows intercalated disks, a nucleus and desmosomes. - Image of Blood Smear: shows Erythrocytes, Leukocytes, platelets, and neutrophils labeled. ## LAB 5! - Heart Dissection -Image of a dissected heart: Shows the right and left auricle, ventricle, pulmonary trunk, aorta # LAB 5! - Open Heart - Image of a dissected heart. Shows the left and right ventricle, left atrium, papillary muscles, Chordae Tendineae, trabeculae carnae # LAB 5! - Open Heart - Image of a dissected heart. Shows the Pulmonary Semilunar valve, Coronary Arteries, Pulmonary and Aortic Semilunar valves