Ch 19 Heart

Pulmonary circuit

Pulmonary circuit

Pumps deoxygenated blood towards lungs for oxygenation and back to the heart

Systemic circuit

Delivers oxygenated blood through body and back to the heart

Atria

2 superior chambers of heart; receive blood from pulmonary and systemic circuit

Ventricles

2 inferior chamber of heart; larger and have more musculature because they pump blood through pulmonary and systemic circuits

Apex

Point of heart; lies left of midline

Base

Superior portion of heart

Mediasternum

Heart is located in (central thoracic area between lungs)

Pericardium

Covering of the heart that consists of two layers

Fibrous pericardium

Strong layer of dense connective tissue; most superficial layer

Serous pericardium

Deeper layer of the pericardium which surrounds the heart; consists of two layers (parietal and visceral) separated by a cavity

Epicardium

Another name for the visceral serous pericardium that surrounds the heart

Myocardium

Cardiac muscle that makes up muscular wall of heart; located between epicardium and endocardium; have circular/spiral arrangement in the heart

Endocardium

Thin layer of connective tissue that lines the heart wall (muscle) and forms the inner lining

Pericardial cavity

Space between parietal serous pericardium and visceral serous pericardium; filled with fluid which lubricates membranes and allows heart to slide across them

Interventricular septa

Separates left and right ventricles

Interatrial septa

Separates left and right atrium

Superior and inferior vena cava, right atrium, tricuspid valve, right ventricle, pulmonary semilunar valve, pulmonary trunk, lung capillaries, pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, aorta

Order of blood flow through the heart starting from vena cava and including valves

Coronary arteries

Blood vessels that supply the heart with oxygenated blood; located on external heart

Coronary sulcus

Groove where coronary arteries run through located between atrium and ventricles on external surface

Superior vena cava

Deoxygenated blood from systemic circuit above the level of the heart drains into...

Right atrium

Heart chamber that makes up right border of the heart; receives blood from superior and inferior vena cava and coronary veins; contains sinoatrial node and fossa ovalis

Inferior vena cava

Venous blood from below the level of the heart drains into ...

Sinoatrial node

Pacemaker of the heart located in the wall of the right atrium and control rhythm of heart beat; creates a signal that travels to both atria and signals all muscle cells to contract together

Fossa ovalis

Remnant of a hole from embryonic heart that connects left and right atrium to bypass pulmonary circuit; closes with change in pressure at birth to form ...

Foramen ovale

Hole in embryonic heart that connects right and left atrium to bypass pulmonary circuit

Tricuspid valve

Connects right atrium and right ventricle and prevents blood from regurgitating back into right atrium

Chordae tendinae

Fibers that anchor atrioventricular valves (tricuspid and bicuspid)

Papillary muscles

Structures that control chordae tendinae to open atrioventricular valves through their contraction

Right ventricle

Oxygen is still deoxygenated when pumped from right atrium into this chamber of the heart; it needs to be pumped into pulmonary circuit

Pulmonary valve

Structure found in pulmonary trunk that keeps blood from regurgitating back into right ventricle and reversing blood flow

Pulmonary trunk

This structure of the heart bifurcates into left and right pulmonary arteries and contains pulmonary valve

Pulmonary veins

Blood is oxygenated in the lungs and returns to heart via these structures (vessels)

Left atrium

Pulmonary veins drain oxygenated blood into this chamber of the heart

Bicuspid valve

Also called mitral valve or left atrioventricular valve; oxygen rich blood crosses this structure from left atrium into left ventricle; it prevents blood from regurgitating back into left atrium; contains chordae tendinae and papillary muscles

Left ventricle

Oxygen rich blood is pumped into aorta from this heart chamber

Aortic valve

Semilunar valve that prevents blood from regurgitating from atrium back into left ventricle

Aorta

First large artery of systemic circuit; contains semilunar valve; branches into smaller arteries to supply oxygen rich blood to body

Endocardium

Each valve is composed of ... with a connective tissue core

Semilunar valves

Valves that are located at the junction of ventricles and great arteries of pulmonary/systemic circuit

Cardiac skeleton

Dense connective tissue structure that surrounds all valves that functions to anchor valve cusps, prevent overdilation, blocks direct spread of impulses, and is the main point of insertion for cardiac muscle

Open

Blood filling the atria and pressing against AV valves causes increased pressure causes AV valve to ... then atrium contracts and pushes rest of blood through

Close

Ventricles contracting causes blood to push against valves and ... them; papillary muscles and chordae tendinae prevent flaps from going into atria

Open

When ventricles contract and pressure rises blood is pushed against semilunar valves causing them to ...

Closed

When ventricles relax pressure falls and blood flows back from arteries filling cusps of semilunar valves and forcing them ...

Atrioventricular

The first lub sound of a heart beat is characteristic of these valves closing

Semilunar

Second dub sound of heart beat is characteristic of these valves closing

2nd right parasternal space

Aortic valve is best heard at

2nd left parasternal intercostal space

Pulmonary valve is best heard at

5th left parasternal intercostal space

Tricuspid valve is best heard at apex of heart located at

5th left intercostal space at midclavicular line

Mitral valve is best heard at

Systole

Contraction of heart chamber (atrium or ventricles)

Diastole

Expansion of heart chamber (atrium or ventricle) after contraction when it refills with blood

Tachycardia

Elevated heart rate 100 bpm+

Bradycardia

Depressed heart rate <60 bpm

Left ventricle

This ventricle has thicker myocardium because it pumps blood to systemic circuit

HOCM

Congenital disorder of the heart wall with enlarge interventricular septum; decreases blood flow of left ventricle and systemic circuit; dangerous during exercise when blood flow to brain or vital organs can be blocked; distinct heart murmur; pre-screening is important for athletes

Myocardium

Name for cardiac muscle; is striated like skeletal muscle and contracts via sliding filament mechanism; contraction pumps blood from heart and vessels

Desmosomes, fasciae adherens, gap junctions

Cell junctions that hold cardiac muscle together

Fasciae adherens

Long desmosome-like junctions

Gap junctions

Hollow channels that allow cardiac muscle cells to communicate quickly and contract together (neurotransmitters are inefficient)

Calcium

Cardiac muscle is stimulated to contract by ... entering sarcoplasm which signals release of more ... by sarcoplasmic reticulum to trigger sliding filament mechanism

Conducting system

System of cardiac muscle that generates and conducts impulses and signals cells to contract rhythmically; includes specialized muscle cells like sinoatrial node

Sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, purkinje fibers

List the pathway of the conducting system

Sinoatrial node

First part of conducting system that creates signal that travels to both atria and stimulates muscle cells to contract together

Atrioventricular node

Conduction from sinoatrial node comes back into the right atrium at the top of atrioventricular septum to this structure

Atrioventricular bundle

Signal of conducting system goes down atrioventricular node to this structure located in interventricular septa

Bundle branches

Structures of conducting system that descend down interventricular septa to apex of heart

Purkinje fibers

Distal bundle branches that stimulates contraction of both ventricles

Depolarization

Cardiac muscle cell is more positively charged

Repolarization

Cardiac muscle returns to normal

QRS

This portion of an ECG graph represents the biggest electrical activity caused by the bundle branches of the conducting system and signals ventricles to contract

P wave

Part of ECG that represents atrial contraction or systole

T wave

Part of ECG that represents repolarization/relaxation/diastole to normal shape

Sinus

How often heart is beating; part of ECG usually 60-100 bpm

Atrial fibrilation

This condition is characteristic of no defined P wave in ECG, atria is not contracting well

Heart block

Results due to slow communication between atria and ventricles

Third degree heart block

Results in no communication between atria and ventricles; contraction occurs randomly and independently

Parsympathetic

Innervation of this division of the ANS decreases hear rate through parasympathetic fibers that run in vagus nerve; cardiac center located in medulla

Sympathetic

Innervation of heart from this division of the ANS increases heart rate and contractile force to pump more blood through systemic circuit

Coronary arteries

Blood supply to muscular walls and tissues of hear arises from base of aorta and runs through coronary sulcus; left and right

Right coronary artery

Blood vessel originates from aorta and travels between right atrium and right ventricle on surface of the heart then travels posteriorly

Left coronary artery

Blood vessel originates from aorta and passes behind pulmonary trunk toward left margin of the hear below the left atrium and bifurcates into anterior interventricular artery and circumflex arteryA

Anterior interventricular artery

Branch of left coronary artery that supplies most of left ventricle; called widow's maker because most common artery to be blocked

Circumflex artery

Branch of left coronary artery that goes toward the back of the heart and supplies lateral wall and posterior left ventricle

Cardiac veins

These blood vessels carry deoxygenated blood from heart to right atrium; they occupy sulci on heart surface; example includes coronary sinus

Coronary sinus

Blood vessel of heart that runs in posterior part of coronary sulcus; returns majority of venous blood from heart to right atrium; cardiac veins drain into this structure on posterior heart

Great cardiac vein, middle cardiac vein, small cardiac vein

Name the major veins of the heart that drain into coronary sinus and into right atrium (3 of them)

Atherosclerosis

Fatty deposits in lumen (hollow opening of blood vessels) of coronary arteries

Angina

Chest pain associated with partial or full blockage of coronary artery

Myocardial infarction

Complete blockage of coronary artery due to severe atherosclerosis; causes cardiac muscle tissue to die; also called heart attack

Heart failure

Progressive weakening of the heart where it cannot meet body's demands for oxygenated bloodCon

Congestive heart failure

Heart overcompensates for weakness due to heart failure and becomes enlarged; reduces pumping efficiency

Angioplasty

Treatment for myocardial infarction where catheter is threaded into blocked coronary artery and balloon is inflated to open blood vessel and restore blood flow

Coronary bypass

Treatment of myocardial infarction; blood vessel is collected from other part of body and sutured to exposed coronary artery to create bypass for blockage

Partial bypass

Treatment for myocardial infarction where diagnosis of atherosclerosis results in prescription of blood thinning medication to prevent blockage

Arrythmias

Variation of normal heart rhythmVe

Ventricular fibrillation

Type of arrhythmia that results in rapid and random firing of electrical impulses in ventricles; crippled conducting system; common cause of cardiac arrest; fluttering instead of complete contraction/relaxation; insufficient blood pumping to systemic circuit; leads to fainting or collapse

Atrial fibrillation

Type of arrhythmia where impulses circle within atrial myocardium stimulating AV node; promotes clot formation and leads to stroke or pulmonary embolus when clot gets stuck in smaller capillaries; episodes of anxiety, fatigue, shortness of breath and palpitations; fibrillation requires correction

Ventricular septal defect

Most common congenital heart defect; consists of a hole in septa that causes oxygen rich and oxygen poor blood to mix into systemic circuit; inadequately oxygenated blood is pumped to tissues and ventricles work harder to increase blood flow; results in fatigue/fainting

Transposition of great vessels

Congenital heart defect where aorta is connected to right ventricle and pulmonary trunk is connected to left ventricle; requires surgical correction; deoxygenated blood passes to systemic circuit and oxygenated blood gets recycled in pulmonary circuit; great vessels are in the wrong place (reflected)