CDS Flashcards
Pumps blood to organ systems (systemic)
Left Ventricle
The Heart Wall
Epicardium
Myocardium
Endocardium
Receives systemic blood
Right atrium
To and from the lungs
Pulmonary Circuit
To and from the rest of the body.
Systemic Circuit
Carry oxygenated blood away from heart and carry it to the capillaries
Arteries
Microscopic vessels where exchange between cells and blood takes place
Capillaries
Deep groove that marks boundary of atria and ventricles
Coronary Sulcus
Receive oxygenated blood from capillaries and carry it back to the heart
Veins
Two Sets of Pumping Chambers in Heart
Left and Right Atrium
Left and Right Ventricles
Pumps blood to lungs (pulmonary)
Right Ventricle
Two layers of Pericardial Cavity
Visceral pericardium (epicardium) Parietal pericardium
Internal Anatomy and Organization
- Interatrial septum
- Interventricular septum
- Atrioventricular valves
Covers heart surface
Visceral pericardium (epicardium)
Heart Pumps Blood into Two Circuits in Sequence
Pulmonary Circuit and Systemic Circuit
Surfaces Features of the Heart
- Auricle
- Coronary Sulcus
- Anterior Ventricular Sulcus
- Posterior Ventricular Sulcus
Receives blood from lungs
Left Atrium
Outer portion of atrium
Auricle
- Middle layer
- Thick Muscle Layer
Myocardium
- Outermost layer of the heart wall
- Serous membrane
Epicardium or Visceral pericardium
Lines pericardial sac that surrounds heart
Parietal pericardium.
Three Kinds of Blood Vessel
Arteries
Capillaries
Veins
- Surrounds the heart
- It is lined by pericardium
- Has Two layers
Pericardial Cavity
supports valves and muscle cells
Fibrous Skeleton
- Located between atrium and ventricle
- Ensure one-way flow from atrium to ventricle
Atrioventricular valves
- Mark boundary between left and right ventricles
- Sulci contain major cardiac blood vessels
- Filled with protective fat
Posterior Ventricular Sulcus
contain major cardiac blood vessels
Sulci
- Inner lining of pumping chambers
- Continuous with endothelium
Endocardium
Separates atria
Interatrial septum
Blood Flow in the heart
• Superior and inferior venae cavae
o Large veins carry systemic blood to right atrium
• Right atrium sends blood to right ventricle
o Flows through right AV valve
Bounded by three cusps (tricuspid valve)
Cusps anchored by chordae tendinae
Chordae attached to papillary muscles
• Right ventricle pumps blood through pulmonary semilunar valve
o Enters pulmonary trunk
o Flows to lungs through right, left pulmonary arteries where it picks up oxygen
• Pulmonary veins carry blood to left atrium
• Left atrium sends blood to left ventricle
o Enters through left AV valve (bicuspid or mitral)
• Left ventricle pumps blood to aorta
o Through aortic semilunar valve to systems
• The left ventricle’s greater workload makes it more _______than the right, but the two pump equal amounts of blood.
massive
It is much thicker than right ventricular myocardium
Left ventricular myocardium
prevent backflow from the ventricles into the atria
AV valves
The 4 chambers of heart
- Right Atrium
- Right Ventricle (with the pulmonary circuit)
- Left Atrium
- Left Ventricle (with the systemic circuit)
prevent backflow from the outflow vessels into the ventricles.
Semilunar valves
Cardiac Muscle Cells
• Shorter than skeletal muscle fibers
• Have single nucleus
• Have striations (sarcomere organization)
• Depend on aerobic metabolism
• Connected by intercalated discs
o Desmosomes transmit tension
o Gap junctions transmit action potential
meets heavy demands of myocardium for oxygen, nutrients
Coronary circulation
Separates ventricles
Interventricular septum
ensure one-way flow of blood
Valves
Provide the pumping action
Contractile cells
branch from aorta base
Coronary arteries (right, left)
ensure constant blood supply
Anastomoses (arterial interconnections)
Drainage is to
Right atrium
- Great, middle cardiac veins drain capillaries
- Empty into coronary sinus
Two types of cardiac cells
- Contractile cells
- Cells of the Conducting System
• A recording of the electrical activity of the heart
The Electrocardiogram (ECG or EKG)
Valves prevent backward flow called
Regurgitation
Differences between Cardiac and Skeletal Muscle Cells
• Cardiac action potential has long plateau phase
• Cardiac muscle has long, slow twitch
• Cardiac muscle has long refractory period
o Can’t be tetanized
Initiates and spreads electrical impulses in heart
Conducting system
Factors Controlling Cardiac Output
• Blood volume reflexes • Autonomic innervation o Heart rate effects o Stroke volume effects • Hormones
Two types of cells in conducting system
Nodal cells and Conducting cells
Heart is
• Heart is self-exciting
o Pacemaker cells establish heart rate
-Normal pacemaker is sinoatrial (SA) node.
o Impulse spreads from SA node:
- Across atria
- To atrioventricular (AV) node.
- To AV bundle and bundle branches
- Via Purkinje fibers to ventricles
Two phases in cardiac cycle
Systole
Diastole
Distributes stimuli to myocardium.
Conducting cells
Generated by closing of valves
Indicate start/stop of systole
Heard with stethoscope
Heart sounds
Ventricular repolarization
T wave
Generate and spread the action potential.
Cells of the Conducing System
o Releases norepinephrine (NE)
o Raises heart rate and stroke volume
Sympathetic innervation
Atrial depolarization
-P wave
Ventricular depolarization
-QRS complex
- Pacemaker cells
- Reach threshold first
- Set heart rate
Nodal cells
Movements and forces generated during cardiac contraction
Heart Dynamics
The heart rate is established by the _____, as modified by autonomic activity, hormones, ions, etc.
SA node
Three main components of electrocardiogram
- P wave
- QRS complex
- T wave
Amount of blood pumped each minute.
Cardiac Output
Relaxation phase
Diastole
o Speeds up heart rate
o Triggered by stretching wall of right atrium
Atrial Reflex
- Contraction phase
- Both ventricles simultaneously
Systole
is amount of blood entering heart
VR
Two main heart sounds
o First sound (lubb)
-Closing of AV valve
o Second sound (dupp)
-Closing of aortic valve
Autonomic Control of the Heart
- Parasympathetic innervation
- Sympathetic innervation
o Increase ventricular output
o Triggered by stretching wall of ventricles
Frank Starling Principle
• A healthy person can increase cardiac output by
three-fold to five-fold.
Blood Volume Reflexes
- Stimulated by changes in venous return
- Atrial reflex
- Frank-Starling principle
o Releases acetylcholine (ACh)
o Lowers heart rate and stroke volume
Parasympathetic innervation
CNS Control of the Heart
• Basic control in medulla oblangata
o Cardioacceleratory center
-Activation of sympathetic neurons
o Cardioinhibitory center
-Governing of parasympathetic neurons
o Other inputs
- Higher centers
- Blood pressure sensors
- Oxygen, carbon dioxide sensors
is the amount of blood pumped by the left ventricle each minute.
Cardiac Output
Amount of blood pumped in a single beat
Stroke Volume
shows the electrical events associated with the heartbeat.
ECG
• Stimulated by changes in venous return
Blood Volume Reflex
Hormone effects on Cardiac Output
• Adrenal medulla hormones
o Epinephrine, norepinephrine released
o Heart rate and stroke volume increased
• Other hormones that increase output
o Thyroid hormones
o Glucagon
