Circulatory System 2.01 Remember the structures of the circulatory system 2.02 Understand the functions and disorders of the circulatory system

Components of the Circulatory System Heart Arteries Veins Capillaries Blood and lymph

The Heart Hollow, muscular, double pump that circulates blood. At rest = 2 oz. blood with each beat, 5 qts./min., 75 gallons/hour. Average= 72 beats per minute. 100,000 beats/day Size of a closed fist

Heart Weighs 12-13 oz Location – thoracic cavity Apex – conical tip, lies on diaphragm, points left Stethoscope instrument used to hear the heartbeat Heart sound is lub dub.

Heart functions circulates blood to all parts of the body Arteries, veins, and capillaries take blood from heart to cells and return to heart Carries O2 and nutrients to cells, carries away waste products. Lymph system returns excess tissue fluid to general circulation.

2.01 Remember the structures of the circulatory system Layers of the heart Pericardium: double layer of fibrous tissue that surrounds the heart Myocardium: cardiac muscle tissue Septum Septum: partition (wall) that separates right half from left half. Pericardium Myocardium Endocardium Endocardium: smooth inner lining of heart 2.01 Remember the structures of the circulatory system 6

Heart Superior vena cava and inferior vena cava bring deoxygenated blood to the right atrium Pulmonary artery takes deoxygenated blood away from the right ventricle to the lungs for O2 . Pulmonary veins bring oxygenated blood from the lungs to left atrium Aorta takes oxygenated blood away from left ventricle to rest of body.

Chambers and Valves Upper chambers: Right and Left atrium Lower chambers: right and left ventricle the left ventricle wall is 3x as thick as the right ventricle wall and forms the apex of the heart. Four heart valves permit flow of blood in one direction

Valves Tricuspid valve: between right atrium and right ventricle Bicuspid (mitral) valve: between left atrium and left ventricle Semilunar valves: located where blood leaves the heart Pulmonary semilunar valve Aortic semilunar

Blood and oxygen supply to the heart is from the coronary arteries.                                          

2.01 Remember the structures of the circulatory system Heart Check your knowledge... Aorta Superior vena cava Pulmonary artery Aortic semilunar valve Pulmonary vein Right atrium Left atrium Tricuspid valve Bicuspid (mitral) valve Inferior vena cava Pulmonary semilunar valve Right ventricle Left ventricle Septum Apex 2.01 Remember the structures of the circulatory system 11

Flow of blood through the body Right side Superior vena cava Inferior vena cava Right atrium Tricuspid valve Right Ventricle Pulmonary valve Pulmonary artery Lungs CO2 and O2 exchange Left Side Pulmonary vein Left atrium Bicuspid valve Left ventricle Aortic valve Aorta Body 2.01 Remember the structures of the circulatory system 12

Conduction system of heart beats 2.01 Remember the structures of the circulatory system 13

Control of Heart Contractions SA (sinoatrial) node:pacemaker of the heart. Located in the right atrium of the heart. sends out electrical impulse Impulse spreads over the atria, making them contract The impulse then travels to the AV node

AV (atrioventricular) Node Conducting cell group between atria and ventricle Carries impulse to bundle of His

Bundle of His Conducting fibers in the septum Divides into R and L branches to network of branches in ventricles (Purkinje fibers) Purkinje Fibers Impulse shoots along Purkinje fibers causing the ventricles to contract.

Electrocardiogram (EKG or ECG) Device used to record the electrical activity of the heart Systole=contraction phase Diastole= relaxation phase P=atrial contraction QRS=ventricular contraction T=ventricular relaxation Holter monitor=24hr. EKG Baseline of an EKG is a flat line

Interpretation of EKG  P wave=enlarged atrium or stenosed AV valve.  Q wave= Myocardial infarction  R wave= Enlarged ventricles  T wave = K+ level too high

Major Blood Circuits General (systemic) circulation Cardiopulmonary circulation

Circulation and Blood Vessels Cardiopulmonary Circulation Systemic Circulation Arterioles Venules Heart and lungs From the heart to the tissues and cells, then back to the heart Smallest arteries Smallest veins

Aorta: largest artery in the body Systemic Circulation Aorta: largest artery in the body First branch is coronary artery Aortic arch Many arteries branch off the descending aorta

Arteries Carry oxygenated blood away from the heart to the capillaries Elastic, muscular and thick-walled Transport blood under very high pressure Arterial blood – lots of oxyhemoglobin = bright red, spurts Arteries > arterioles > capillaries

Capillaries Smallest blood vessels, can only be seen with a microscope Connect arterioles with venules Walls are one-cell thick and extremely thin-allow for selective permeability of nutrients, oxygen, CO2 and metabolic wastes

Veins Carry deoxygenated blood away from capillaries to the heart contain a muscular layer, but less elastic and muscular than arteries Thin walled, collapse easily when not filled with blood Valves permit flow of blood only in direction of the heart Jugular vein- located in the neck Venous blood – lots of CO2, poor oxygen = dark crimson, oozes Veins > Venules > Capillaries

Blood Pressure- is the surge of blood when the heart pumps creating pressure against the walls of the arteries. Systolic Pressure Diastolic Pressure Measured during the contraction phase Measured when the ventricles are relaxed Normal average systolic pressure= 120 Normal average diastolic pressure =80

Pulse alternating expansion and contraction of an artery as blood flows through it. Pulse sites Temporal External maxillary Carotid Brachial Radial Femoral Popliteal Posterior Tibial Pedal

2.01 Remember the structures of the circulatory system Common pulse sites 2.01 Remember the structures of the circulatory system 27 27