Cardiovascular I

Overview General Introduction/Function Red Blood Cells Hemoglobin Hematopoiesis Heart Anatomy Skeletal versus Cardiac Muscle Electrical conduction in the heart

Composition of Blood Blood is the body’s only fluid tissue Formed elements: Hematocrit

Composition of Blood Figure 18.1

Protection Blood prevents blood loss by: – Activating plasma proteins and platelets – Initiating clot formation when a vessel is broken Blood prevents infection by: – Synthesizing and utilizing antibodies – Activating complement proteins – Activating WBCs to defend the body against foreign invaders

Formed Elements Erythrocytes, leukocytes, and platelets make up the formed elements Most formed elements survive in the bloodstream for only a few days Most blood cells do not divide

Erythrocytes (RBCs) Figure 18.3

Erythrocyte Function Figure 18.4a, b

Hematopoiesis Blood cell formation Hematopoiesis occurs in the red bone marrow

Production of Erythrocytes: Erythropoiesis Figure 18.5

Hormonal Control of Erythropoiesis Figure 18.6

Heart Anatomy

Figure 19.4e

Heart Covering & Heart Wall Pericardium Epicardium Myocardium Endocardium Figure 19.2

Figure 19.4e

Atria

Figure 19.4e Ventricles

Figure 19.4e Major Vessels

Pathway of Blood through the Heart and Lungs Right atrium  tricuspid valve  right ventricle  pulmonary semilunar valve  pulmonary arteries  lungs  pulmonary veins  left atrium  bicuspid valve  left ventricle  aortic semilunar valve  aorta  systemic circulation

Pathway of Blood through the Heart and Lungs Figure 19.5

Coronary Circulation Functional blood supply to the heart Shortest circulation Arterial supply arises from the base of the aorta – Right coronary artery – Left coronary artery

Homeostatic Imbalances Angina pectoris Myocardial infarction

Heart Valves Heart valves insure unidirectional blood flow through the heart Atrioventricular (AV) valves – Bicuspid – Tricuspid

Heart Valves Figure 19.9

Heart Valves Aortic semilunar valve Pulmonary semilunar valve Semilunar valves prevent backflow of blood into the ventricles

Heart Valves Figure 19.10

Thought Question

Microscopic Heart Muscle Anatomy Figure 19.11b

Skeletal vs. Cardiac Muscle 1)Means of Stimulation 1)Cardiac muscle cells are self-excitable and can initiate their own depolarization

Heart Physiology: Intrinsic Conduction System

Figure 12.10

Figure 12.22

Figure 12.23

Skeletal vs. Cardiac Muscle 1)Means of Stimulation 1)Cardiac muscle cells are self-excitable and can initiate their own depolarization 2)Organ versus Motor Unit Contraction 1)Heart contracts as a unit or not at all

Skeletal vs. Cardiac Muscle 1)Means of Stimulation 1)Cardiac muscle cells are self-excitable and can initiate their own depolarization 2)Organ versus Motor Unit Contraction 1)Heart contracts as a unit or not at all 3)Length of Absolute Refractory Period 1)Long refractory period 2)Sodium channels are inactivated for almost as long as the contraction

Energy Requirements Needs oxygen to produce ATP Can use multiple fuel molecules including glucose and fatty acids

Homeostatic Imbalances If heart does not get enough oxygen  production of lactic acid Gap junctions close and cells become electrically isolated If area is large, then pumping activity of the heart can be impaired

Heart Physiology: Sequence of Excitation Figure 19.14a

Thought Questions

Homeostatic Imbalances Arhythmias Fibrillation Defective SA node

Electrocardiography Figure 19.16

Figure 12.11

Thought Questions

Overview General Introduction/Function Red Blood Cells Hemoglobin Hematopoiesis Heart Anatomy Skeletal versus Cardiac Muscle Electrical conduction in the heart

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