Heart Flashcards
Peripheral heart
We have 2 calf muscles that help blood pump back t the heart therefore we have 2 peripheral hearts
Pulmonary circuit
Right side of heart
It carries blood to lungs for gas exchange and then back to the heart
Systemic circuit
Left side of heart
Supplies oxygenated blood to all the tissues of the body and returns it to the heart
Heart is located in
Mediastinum
Between the lungs
Base of the heart
Wide, superior position of heart
Large vessels are attached here
Apex of the heart
Tapered inferior end
Titled to the left
Pericardium
Allows the heart to beat without friction
Gives room to expand bu resists excessive expansion
Anchored to diaphragm inferiority and sternum anteriorly
Double walled sac
Parietal pericardium
Superficial fibrous layer of connective tissue
Deep thin serous layer
Visceral pericardium
EPICARDIUM
Serous membrane covering the heart
Pericardial cavity
Space inside the pericardial sac
filled with 5-30 mL of pericardial fluid
Pericarditis
Painful inflammation of the membranes
Why are ventricles thicker muscles
Because they are pumping blood
Why wis the right ventricle thinner than the left ventricle
Because the right ventricle sends blood to lungs
The left ventricle sends blood to the toes (WHICH IS THE FURTHEST DISTANCE) so it needs more cardiac muscle
What are the 3 layers of the heart wall
Epicardium
Myocardium
Endocardium
Endocardium
INSIDE
MADE BY EPITHELIAL TISSUE
Smooth inner lining of heart and blood vessels
Covers the valve surfaces and is continuous with endothelium of blood vessels
Epicardium
VISCERAL PERICARDIUM
OUTSIDE
Serious membrane covering heart
Adipose in thick layer in some places
Coronary blood vessels travel through this layer
Myocardium
MIDDLE
Layer of cardiac muscle proportional to workload
Fibrous skeleton of the heart: framework of collagenous and elastic fibers
Provides structural support and attachment for cardiac muscle and anchor for valve tissue
Electrical insulation between atria and ventricles; important in timing and coordination of contractile activity
Cardiocytes
Striated, short, thick, branched cells, one central nucleus
Intercalated discs
Join cardiocytes end to end
Right and left atria chambers
Two superior chambers
Receive blood returning to heart
Right and left ventricle Chambers’s
Two inferior chambers
Pump blood into arteries
Veins contain ____ blood
CO2 contained
All veins carry CO2 contained blood EXCEPT
Pulmonary veins (WHICH CARRY O2 RICH BLOOD)
All arteries carry O2 rich blood EXCEPT
Pulmonary arteries (WHICH CARRY CO2 RICH BLOOD)
CYANOSIS
When someone a has a hole in their heart or septum
Lips and fingernails turn blue because you are getting less oxygen
Atrium is _____ blood
Ventricles are _______ blood
Atrium is receiving blood
Ventricles are pumping blood
TRUE OR FALSE
Ventricles fill up and contract at the same time
Ventricles relax at the same time
True
When ventricle contacts the atrium_____
Relaxes
When the atrium contracts the ventricle ____
Relaxes
Aorta carries O2 from the heart to
Other parts of the body
Right coronary artery
Longer
Come out aorta
Supplying right atrium and right ventricle
Supplies O2 and nutrients
Heart needs a lot of
O2 and glucose
Normal heart rate for adults
72-84bpm
Atrioventricular sulcus
Separates atria and ventricles
Interventricular sulcus
Overlies the inter ventricular septum that divides the right ventricle from the left
Sulci contain
Coronary arteries
Interatrial septum
Wall that separates atria
Pectinate muscles
Internal ridges of myocardium in right atrium and both auricle
Interventricular septum
Muscular wall that separates ventricles
SO THAT YOU DONT MIX THE CO2 FROM THE RIGHT VENTRICLE WITH THE O2 IN THE LEFT VENTRICLE double check
Trabeculae carneae
Internal ridges in both ventricles
May prevent ventricle walls from sticking together after contraction
What is the job of a valve
Ensure one way flow of blood through the heart
Atrioventricular (AV) valves
Control blood flow between atria and ventricles
How many cusps does the right AV valve have
Three cusps THIS BECOMES A TRICUSPID VALVE
How many cusps does the left AV valve have
2 cusps
THIS BECOMES THE MITRAL VALVE
OR THE BICUSPID
Chordate tendineae
Cords that connect AV valves to papillary muscles that are on the floor of ventricles
This prevents the AV valves from bulging into atria when ventricles contract
The papillary muscle
Has 2-3 attachments to the heart floor to distribute physical stress, coordinate timing of electrical conduction and provide redundancy
Semilunar valves
Control flow into arteries
Open and close because of blood flow and pressure
Pulmonary semilunar valve
Betweeen right ventricle and pulmonary trunk
Aortic semilunar valve
Between left ventricle and aorta
When the ventricles relax
Pressure drops inside the ventricles
Semilunar valves close as blood attempts to back up into the ventricles from the vessels
The AV valves open
Blood flows from atria to ventricles
When the ventricles contact
AV valves close ass blood attempts to back up into the atria
Pressure rises inside the ventricles
Semilunar valves open and blood flows into great vessels
Blood pathway travels from
The right atrium
To the pulmonary circuit
Then the systemic circuit
Back to the beginning
Heart gets the coronary circulation to
Sustain its strenuous workload
Needs abundant O2 and nutrients
Left coronary artery (LCA) and right coronary artery(RCA) branches off the ascending aorta
Left coronary artery
Supplies blood into both ventricles and anterior 2/3 of the interventricular septum
Supplies left atrium and posterior wall of left ventricle
Right coronary artery
Supplies right atrium and sinoatrial node (pacemaker)
Supplies posterior walls of ventricles
Myocardial infarction
Heart attack
Interruption of blood supply to the heart from a blood clot or fatty deposit (atheroma) can cause death of cardiac cells within minutes
Arterial anastomoses
Provide alternative routes of blood flow(collateral circulation) within the myocardium when someone is having a heart attack
Angina pectoris
Chest pain from partially obstruction of coronary blood flow
Venous drainage
Most coronary blood returns to right atrium by CORONARY SINUS
Large transverse vein in coronary sulcus on posterior side of heart
Collects blood and empties into right atrium
The conduction system
Coordinates the heartbeat
[which is composed of an internal pacemaker and nerve like conduction pathways through myocardium]
Generates and conducts rhythmic electrical signals in a specific order
The order of electrical signals
Sinoatrial node (SA)
Atrioventricular (AV) node
Atrioventricular (AV) bundle
Purkinje fibers
Sinoatrial node
Modified cardiocytes
Pacemaker initiates each heartbeat and determines heart rate
Pacemaker in right atrium near base of superior vena cava
Signals spread throughout atria
Atrioventricular node
Located near the right AV Val ave at lower end of interatrial septum
Electrical gateway to the ventricles
Fibrous skeleton: insulator prevents currents from getting to ventricles by any route
Atrioventricular bundle
Bundle forks into right and left bundle branches
Branches pass through interventricular septum toward apex
BUNDLE OF HIS
Purkinje fibers
Nerve like processes spread throughout ventricular myocardium
Sympathetic nerves
Increase heart rate and contraction strength
Fibers terminate in SA and AV nodes, in atrial and ventricular myocardium (ALSO AORTA, PULMONARY TRUNK AND CORONARY ARTERIES )
Parasympathetic nerves
Slow heart rate (from the vagus nerves)
Cardiac cycle
Systole: contraction
Diastole: relaxation
Refers to the action of the ventricles
Impulse conduction to the myocardium
Signal from SA node stimulates 2 atria to contract almost simultaneously
(Reaches AV node in 50 ms)
Signal slows down through AV node
(Delays signal 100 ms and this gives the ventricles time to fill)
Signals travel quickly through AV bundle and purkinje fibers
Ventricular systole progresses up from the apex of the heart
Cardiocytes have a stable resting potential of ____ and depolarize only when stimulated
-90mV
3 phases of cardiocytes action potential
Depolarization
Plateau
Repolarization
Depolarization phase
Stimulus opens gates and Na+ comes in
Membrane depolarizers rapidly
Action potential. Peaks at +30mV
An+ gates close quickly
Plateau phase
Sustains contraction for expulsion of blood from heart
Ca2+ channels open
Repolarization phase:
Ca2+ channels close
K+ channels open
Rapid diffusion of K+ out of cell returns it to resting potential
Electrical behavior of the myocardium
Na + gates open
Rapid depolarization
Na+ gates close
Slow Ca2+ channels open
Ca2+ channels close
K+ channels open (Repolarization)
Electrocardiogram
ECG or EKG
Composite of all action potentials of nodal and myocardial cells detected, amplified and recorded by electrodes on arms, legs, and chest
P wave
SA node fires, atria depolarize and contract
Atrial systole begins
QRS complex
Ventricular depolarization
ST segment
Ventricular depolarization
ST segment
Ventricular systole
Corresponds to plateau in myocardial action potential
T wave
Ventricular repolarization and relaxation
Deviations of ECG from normal can indicate
Myocardial infarction
Abnormalities in conduction pathways
Heart enlargement
Electrolyte and hormone imbalances
Cardiac cycle
One complete contraction and relaxation of all 4 chambers of heart
Total duration: 0.8 seconds
Auscultation
Listening to sounds made by the body
First heart sound (s1)
Louder
Longer
Lubb
Happens when the AV valves close , turbulence in the blood stream and movements of the heart wall
Second heart sound (S2)
Softer and sharper
Dupp
When the semilunar valves close, turbulence in the blood stream and movements of the heart wall
NORMAL PEOPLE ONLY HAVE THESE TWO SOUNDS
Cardiac output (CO)
Amount ejected by each ventricle in 1 minute
CO= heart rate x stroke volume
4-6 L in one minute
Pulse
Surge of pressure made by the heart beat that can be felt by palpating a superficial artery
Heart rate of an infant
120 bpm or more
Adult heart rate
72-80 bpm
Tachycardia
Heart rate over 90 bpm
Stress, anxiety, drugs, heart disease, fever
Loss of blood. Or damage to myocardium
Bradycardia
Heart rate of less than 60 bpm
In sleep,low body temperature, and endurance trained athletes
Stroke volume
The amount of blood ejected by the left ventricle in one contraction
Coronary artery disease (CAD)
A constriction of the coronary arteries
Result of atherosclerosis
Begins when endothelium is damaged by hypertension or diabetes
Atherosclerosis
An accumulation of lipid deposits that degrade the arterial wall and obstruct the lumen