11 The Cardiovascular System Lesson 11.1: Heart Anatomy and the Function of the Cardiovascular System Lesson 11.2: Regulation of the Heart Lesson 11.3: Blood Vessels and Circulation Lesson 11.4: Heart Disease

Heart Anatomy and the Function of the Cardiovascular System Chapter 11: The Cardiovascular System Lesson 11.1 Heart Anatomy and the Function of the Cardiovascular System

Cardiovascular System Includes: heart, blood vessels, and blood Functions: transports oxygen, hormones, and other nutrients to cells rids the body of carbon dioxide and other metabolic waste products helps regulate body temp by vasodilation and vasoconstriction assists with immune function

The Heart a normal healthy adult heart beats 72-82 bpm located in the thoracic cavity between the lungs and under the sternum centered in the chest and tilted slightly to the left sits on the diaphragm base is at the top of the heart and apex is at the bottom of the heart

The Heart: Location and Size

The Four Chambers of the Heart right atrium and right ventricle left atrium and left ventricle atria act as low pressure, collecting chambers ventricles act as powerful pumps septums prevent oxygen-rich blood from mixing with oxygen-poor blood interatrial septum separates right and left atria interventricular septum separates right and left ventricles

The Four Chambers of the Heart right atrium receives deoxygenated blood from the venous system via the superior vena cava and inferior vena cava right ventricle pumps blood to the lungs left atrium receives oxygenated blood from the lungs left ventricle pumps blood through the aorta to the body

The Heart Valves permit blood to flow only in one direction atrioventricular (AV) valves located between atria and ventricles when open, allow blood to flow from atria to ventricles tricuspid 3 cusps (flaps) located on the right side of the heart bicuspid (mitral) 2 cusps (flaps) located on the left side of the heart chordae tendineae attach cusps to papillary muscles to secure the AV valves in place

The Heart Valves semilunar valves allow blood to flow from the ventricles to the lungs and the rest of the body consist of 3 semilunar cusps pulmonary valve located on the right side of the heart at the opening of the pulmonary artery aortic valve located on the left side of the heart at the opening of the aorta

Blood Flow through the Heart

Blood Flow Through the Heart Deoxygenated blood enters the right atrium through the inferior vena cava and superior vena cava The collecting blood in the right atrium increases the pressure against the tricuspid valve, causing the valve to open After the right ventricle fills passively with blood, the right atrium contracts, forcing the remaining blood into the right ventricle Right ventricle contracts – increasing pressure causes the tricuspid valve to close and the pulmonary valve to open forcing the blood into the pulmonary artery Pulmonary artery carries the blood to the lungs where it is oxygenated

Blood Flow Through the Heart Oxygenated blood returns to the left atrium via the pulmonary veins Blood collecting in the left atrium increases the pressure in the chamber, forcing the mitral valve open After the left ventricle fills passively with blood, the left atrium contracts which forces the remaining blood into the left ventricle The left ventricle contracts – increasing pressure causes the mitral valve to close and the aortic valve to open The oxygenated blood travels through the aorta and to all parts of the body

heart diagram heart animation

Walls of the Heart pericardium fluid-filled sac 3 layers fibrous pericardium outer wall that anchors the heart to surrounding structures parietal pericardium epicardium parietal pericardium and epicardium are separated by the fluid-filled pericardial cavity

The Heart 3 layers epicardium myocardium endocardium also the innermost layer of the pericardium outermost layer of the heart surface contains the coronary arteries myocardium middle layer that makes up about 2/3rds of the heart muscle “workhorse” of the heart endocardium innermost layer lines the interior of the heart chambers and covers the valves pf the heart helps blood flow smoothly through the heart

Cardiac Cycle 2 phases – contraction and relaxation diastole 4 chambers undergo period of relaxation chambers fill with blood 2nd number of blood pressure reading systole period of contraction chambers are pumping blood out of the heart 1st number of blood pressure reading 1 cardiac cycle is 0.81 seconds in duration 2/3rds of the cardiac cycle is spent in diastole, 1/3rd is spent in systole

Cardiac Cycle lub-dub sound of heart “lub” produced by the closing of the AV valves “dub” produced by the closing of the semilunar valves an additional sound may indicate a heart murmur when the valves don’t close properly

Cardiac Output cardiac output stroke volume amount of blood pumped from the heart per minute (liters/minute) stroke volume amount of blood pumped from the heart per beat (mL/beat)

Review and Assessment Match these words with 1–4 below: tricuspid, thoracic cavity, ventricle, aortic. 1. atrioventricular valve 2. semilunar valve 3. location of heart 4. heart chamber

Blood Flow through the Heart (1) deoxygenated blood flows from the body to the inferior and superior vena cavae to right atrium (2) right atrium contracts, forcing blood through the tricuspid valve to right ventricle (3) right ventricle contracts, forcing blood through the pulmonary valve, to the pulmonary artery (4) blood exits to the lungs

Blood Flow through the Heart (continued) (5) oxygenated blood from lungs travels through the pulmonary veins to the left atrium (6) left atrium contracts, forcing blood through the mitral valve to the left ventricle (7) left ventricle contracts, forcing blood through the aortic valve (8) blood passes to the aorta (9) blood travels out to parts of the body

Blood Flow through the Heart

Walls of the Heart epicardium myocardium endocardium outermost layer middle layer endocardium inner layer

Cardiac Cycle diastole systole mean arterial pressure ventricle relax, atria contract systole ventricles contract, atria relax mean arterial pressure overall pressure within cardiovascular system

Cardiac Output amount of blood pumped by heart in 1 minute measured in liters/minute stroke volume amount of blood pumped in 1 beat heart rate number of beats per minute

Review and Assessment True or False? 1. The ventricles contract in diastole. 2. Stroke volume is measured in beats/minute. 3. The epicardium is the inner heart layer. 4. Deoxygenated blood enters the left atrium. 5. The aortic valve is in the left ventricle.

Regulation of the Heart Chapter 11: The Cardiovascular System Lesson 11.2 Regulation of the Heart

Regulation of the Heart internal control of the heart sinoatrial node (SA node) also called the pacemaker located at the top of the right atrium sends out an electrical impulse that tells the heart to beat at a rate of between 60 and 100 bpm

Regulation of the Heart external control cardiac center located in the medulla oblongata consists of sympathetic and parasympathetic branches sympathetic stimulation increases the heart rate affected by emotions and physical activity parasympathetic stimulation decreases the heart rate dominant when you are at rest releases acetylcholine to decrease heart rate

Regulation of the Heart External control (cont’d) endocrine system adrenal medulla secretes epinephrine and norepinephrine to increase heart rate thyroid gland releases thyroxine to increase heart rate

The Conduction System SA node sends the electrical impulse to the left atrium and to the atrioventricular node (AV node). The electrical impulse is delayed briefly at the AV node. The impulse travels down the left bundle branches and right bundle branches to the Purkinje fibers in both the left and right ventricles. The Purkinje fibers stimulate the ventricles to contract Heart Diagram Conduction Animation

The Conduction System

Electrocardiogram ECG or EKG electrical activity of the heart when the atria and ventricles contract = depolarize when the atria and ventricles relax = repolarize

Electrocardiogram Electrical Event Mechanical Event ECG Recording SA node fires Atria contract P wave Impulse travels to Purkinje fibers Ventricles contract QRS complex Ventricles relax Atria and ventricles fill T wave

Review and Assessment Match these words with 1–4 below: parasympathetic, EKG, SA node, sympathetic. 1. speed up 2. slow down 3. pacemaker 4. electrical activity of the heart

Cardiac Arrhythmias normal contractility condition sinus rhythm abnormal contractility condition arrhythmia ventricle or atria contraction is not normal

Cardiac Arrhythmias bradycardia tachycardia slow heart beat tachycardia fast heart beat premature atrial contraction (PACs) atria contracts before SA node

Cardiac Arrhythmias atrial fibrillation atria contract faster than 350 bpm premature ventricular contractions (PVCs) ventricles contract too soon ventricular tachycardia (VT) ventricles, rather than SA node, cause beat

Cardiac Arrhythmias ventricular fibrillation (VF) heart block ventricles contract faster than 350 bpm heart block impulse from SA node to AV node first–impulse delayed second–intermittently blocked third–completely blocked

Defibrillators and Life-Threatening Arrhythmias automatic external defibrillator (AED) electric shock stops heart allows heart to start normal rhythm anyone can use one

Review and Assessment Fill in the blanks with: Tachycardia, Atrial fibrillation, Bradycardia, or Defibrillator. 1. _______________ is fast heart beat. 2. _______________ is slow heart beat. 3. _______________ is atria beating more than 350 bpm. 4. A(n) _______________ stops the heart so it can reset.

Blood Vessels and Circulation Chapter 11: The Cardiovascular System Lesson 11.3 Blood Vessels and Circulation

Blood Vessels and Circulation blood vessels: the transport network circulation: moving blood around the body taking vital signs know your numbers

Blood Vessels: The Transport Network structure and function of vessels

The Three Layers of Blood Vessels tunica intima innermost layer tunica media middle layer tunica externa outermost layer

Differences between Arteries and Veins

Capillaries exchange vessels capillary bed precapillary sphincters gas moves between tissue and blood capillary bed network of exchange vessels precapillary sphincters close off capillary bed as needed

Circulation: Moving Blood around the Body cardiopulmonary circulation between heart and lungs systemic circulation between heart and body

Circulation: Moving Blood around the Body

Review and Assessment True or False? 1. Systemic circulation moves blood to lungs. 2. Capillaries are exchange vessels. 3. The tunica intima is the innermost layer. 4. Arteries move blood away from the heart. 5. Veins move blood toward the heart.

Cardiac Circulation coronary arteries left right coronary sinus

Hepatic Portal Circulation maintains proper levels in the blood carbohydrate fat protein

Arteries

Veins

Fetal Circulation placenta vena cava right atrium foramen ovale right ventricle ductus arteriosus

Taking Vital Signs taking your pulse measuring blood pressure find radial, carotid or brachial artery count beats for 15 seconds, multiply by 4 measuring blood pressure stethoscope, sphygmomanometer systolic/diastolic pressure Joseph Dilag/Shutterstock.com, Ilya Andriyanov/Shutterstock.com

Know Your Numbers weight blood pressure cholesterol body mass index–weight to height blood pressure systolic/diastolic–110/70 mmHg cholesterol LDLs and HDLs

Review and Assessment Match these words with 1–4 below: foramen ovule, cholesterol, pulse, blood pressure. 1. systolic/diastolic 2. fetal circulation 3. LDLs and HDLs 4. carotid artery

Chapter 11: The Cardiovascular System Lesson 11.4 Heart Disease

Heart Disease valve abnormalities diseases ending in -itis heart failure diseases of the arteries

Heart Disease heart attack hypertension peripheral vascular disease stroke

Valve Abnormalities heart murmurs valvular stenosis valves do not close properly valvular stenosis narrowed, stiff heart valve mitral valve prolapse mitral valve does not fully close palpitations

Diseases Ending in -itis pericarditis inflammation of heart sac myocarditis inflammation of heart muscle endocarditis inflammation of heart lining and valves

Heart Failure heart cannot pump blood fluid backs up in lungs liver limbs gastrointestinal tract

Diseases of the Arteries aneurysms weakened artery bulges, may break coronary artery disease atherosclerosis angina pectoris ischemia

Heart Attack myocardial infarction treatment plaque blocks a cardiac artery treatment aspirin as soon as symptoms appear 20–60 minute window for treatment

Heart Attack

Heart Disease hypertension peripheral vascular disease stroke blood pressure above 140/90 mmHg peripheral vascular disease lack of circulation in legs stroke blockage of brain blood flow ischemic stroke hemorrhagic stroke transient ischemic attack (TIA)

Review and Assessment True or False? 1. Hypertension is 120/80 mmHg. 2. Aspirin helps in a heart attack. 3. An aneurysm is a weakened artery. 4. Myocarditis affects the heart wall. 5. In a heart murmur the valves do not close properly.