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Cardiovascular System Chaper 12
Pathophysiology (Chamberlain University)
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Chapter 12 Cardiovascular System Disorders
Circulatory System
The circulatory system is composed of:
Vessels
Fluid
Pump
Blood flows from systemic to pulmonary to systemic circulation.
Heart: Anatomy
Located in the mediastinum
Located in the pericardial sac
Parietal pericardium
Epicardium (visceral pericardium)
Pericardial cavity
Myocardium
Endocardium
Heart valves
Atrioventricular valves
Semilunar valves
Septum
Heart: Conduction System
Conduction pathway
Sinoatrial (SA) node
Pacemaker
Sinus rhythm
Atrioventricular (AV) node
Located in floor of the right atrium
AV bundle (Bundle of His)
Right and left branches
Purkinje fibers
Terminal fibers
Electrocardiogram (ECG)
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P wave
Depolarization of atria
QRS wave
Depolarization of ventricles
T wave
Repolarization of ventricles
Cardiac Conduction System
Control of the Heart
Cardiac control center in medulla oblongata
Controls rate and force of contraction
Located in the medulla
Baroreceptors
Detect changes in blood pressure
Located in the aorta and internal carotid arteries
Sympathetic stimulation (cardiac accelerator nerve)
Increases heart rate (tachycardia)
Parasympathetic stimulation (cranial nerve [CN] X; vagus nerve)
Decreases heart rate (bradycardia)
Factors that Increase Heart Rate
Increased thyroid hormones or epinephrine
Elevated body temperature, infection
Example: Fever
Increased environmental temperature
Especially in high humidity
Exertion or exercise
Smoking
Stress response
Pregnancy
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Pain
Coronary Circulation
Right and left coronary arteries
Branch of aorta immediately distal to the aortic valve
Part of the systemic circulation
Left coronary artery divides into:
Left anterior descending or interventricular artery
Left circumflex artery
Right coronary artery branches
Right marginal artery
Posterior interventricular artery
Many small branches extend from these arteries to supply the myocardium and endocardium.
Collateral circulation is extremely limited.
Cardiac Cycle
Diastole
Relaxation of myocardium required for filling chambers
Systole
Contraction of myocardium provides increase in pressure to eject blood.
Cycle begins with
Atria relaxed, filling with blood AV valves open blood flows into ventricles atria
contract, remaining blood forced into ventricles atria relax ventricles contract AV valves
close semilunar valves open blood into aorta and pulmonary artery ventricles relax
Heart Sounds
“Lubb-dub”
“Lubb”—closure of AV valves
Downloaded by damaris mutuli ()
Cardiovascular System Chaper 12
Pathophysiology (Chamberlain University)
Scan to open on Studocu
Studocu is not sponsored or endorsed by any college or university
Downloaded by damaris mutuli ()
, lOMoARcPSD|46240884
Chapter 12 Cardiovascular System Disorders
Circulatory System
The circulatory system is composed of:
Vessels
Fluid
Pump
Blood flows from systemic to pulmonary to systemic circulation.
Heart: Anatomy
Located in the mediastinum
Located in the pericardial sac
Parietal pericardium
Epicardium (visceral pericardium)
Pericardial cavity
Myocardium
Endocardium
Heart valves
Atrioventricular valves
Semilunar valves
Septum
Heart: Conduction System
Conduction pathway
Sinoatrial (SA) node
Pacemaker
Sinus rhythm
Atrioventricular (AV) node
Located in floor of the right atrium
AV bundle (Bundle of His)
Right and left branches
Purkinje fibers
Terminal fibers
Electrocardiogram (ECG)
Downloaded by damaris mutuli ()
, lOMoARcPSD|46240884
P wave
Depolarization of atria
QRS wave
Depolarization of ventricles
T wave
Repolarization of ventricles
Cardiac Conduction System
Control of the Heart
Cardiac control center in medulla oblongata
Controls rate and force of contraction
Located in the medulla
Baroreceptors
Detect changes in blood pressure
Located in the aorta and internal carotid arteries
Sympathetic stimulation (cardiac accelerator nerve)
Increases heart rate (tachycardia)
Parasympathetic stimulation (cranial nerve [CN] X; vagus nerve)
Decreases heart rate (bradycardia)
Factors that Increase Heart Rate
Increased thyroid hormones or epinephrine
Elevated body temperature, infection
Example: Fever
Increased environmental temperature
Especially in high humidity
Exertion or exercise
Smoking
Stress response
Pregnancy
Downloaded by damaris mutuli ()
, lOMoARcPSD|46240884
Pain
Coronary Circulation
Right and left coronary arteries
Branch of aorta immediately distal to the aortic valve
Part of the systemic circulation
Left coronary artery divides into:
Left anterior descending or interventricular artery
Left circumflex artery
Right coronary artery branches
Right marginal artery
Posterior interventricular artery
Many small branches extend from these arteries to supply the myocardium and endocardium.
Collateral circulation is extremely limited.
Cardiac Cycle
Diastole
Relaxation of myocardium required for filling chambers
Systole
Contraction of myocardium provides increase in pressure to eject blood.
Cycle begins with
Atria relaxed, filling with blood AV valves open blood flows into ventricles atria
contract, remaining blood forced into ventricles atria relax ventricles contract AV valves
close semilunar valves open blood into aorta and pulmonary artery ventricles relax
Heart Sounds
“Lubb-dub”
“Lubb”—closure of AV valves
Downloaded by damaris mutuli ()
