Heart Flashcards
What are the divisions of the inferior mediastinum
Anterior, middle, posterior
What are the contents of the superior mediastinum
Thymus R/L brachiocephalic vein Superior vena cava Trachea Esophagus
What are the contents of the inferior anterior mediastinum
Thymus
Internal thoracic a/v
Fat
Lymph nodes
What are the contents of the inferior middle mediastinum
Superior vena cava Ascending aorta Pulmonary a/v Pulmonary trunk Heart Pericardium Phrenic n Inferior vena cava
What are the contents for the inferior posterior mediastinum
Descending aorta Azygos veins Thoracic duct Esophagus Nerve plexus Sympathetic
What branches are given off the aorta
Brachiocephalic trunk
L common carotid
L subclavian
What branches are given off the brachiocephalic trunk
R common carotid
R subclavian
What are the layers of the protective coverings of the heart out to in
Fibrous pericardium
Partial pericardium
Visceral pericardium (epicardium)
What are the layers of the heart out to in
Epicardium
Myocardium
Endocardium
What are the functions of the parietal sac
Protect heart
Lubricate heart
Prevent cardiac distension
What is the parietal cavity
Narrow space between partial and visceral pericardium
Allows uninhibited movement of heart
Small amount of fluid
Attachments for pericardium
Central tendon
Posterior sternum
Posterior mediastinum
What nerve innervates pericardium
Phrenic n
What is pericardial effusion
A rapid accumulation of excess fluid within the parietal sac
Sac compress heart (cardiac tamponade) resulting in heart failure
Because fibrous pericardium does not distend
Outer layer of heart
Composed of visceral pericardium and serous pericardium
Fat and coronary vessels are deep to epicardium
Epicardium
Middle of heart
Cardiac muscle responsible for contraction
Myocardium
Internal layer of heart
Endothelial cells
Lines the lumen of four chambers
Lines cusps of valves
Endocardium
Where is the apex
Inferiolateral left ventricle
Midclavicular 5th intercostal space
Remains motionless throughout contraction
Sound of mitral valve
What is the base of heart and location
Posterior aspect of heart
Mostly left atrium
Lesser contributions than right atrium
Contacts with esophagus
Superior and inferior vena cava to
Right atrium
Right atrium to right ventricle you go through
Tricuspid valve
Leaving right ventricle blood travels through
Pulmonary valve to pulmonary trunk to pulmonary arteries and to lungs
When blood first leaves the lungs it goes through
Pulmonary veins with oxygenated blood
From pulmonary veins to
Left atrium
After leaving left atrium blood flows through
Bicuspid/mitral valve
After passing bicuspid valve, blood goes through
Left ventricle
Left ventricle blood then flows through what valve
Aortic semilunar valve to aorta
From aorta, blood goes
To the body then back to the superior and inferior vena cava
The left pump of the heart does what
Receives oxygenated blood from the lungs and sends it back to the body via the systemic (systole) and coronary (diastole) circulation
What is the function of superior vena cava
Returns deoxygenated blood from tissues ABOVE diaphragm to right atrium
What is the function of inferior vena cava
Return deoxygenated blood from tissues BELOW diaphragm to the right atrium
What is the function of the coronary sinus
Returns deoxygenated blood from the myocardium by coronary circulation to right atrium
What is diastole
Ventricles relax
Ventricles fill with blood
AV valves are open
What is systole
Ventricles contract
Blood is forced from ventricles into aorta or pulmonary arteries
Aortic and pulmonary valves are open
What is the right atrial appendage auricle
Add on room
Muscular pouch
Projects from right atrium
Increases capacity of atrium as it overlaps the ascending aorta
Rough myocardium on internal surface of the auricle
In both R/L atrium
Pectinate muscles
Internal vertical ridge separating the smooth and rough parts of R atrium
Extends to SVC and IVC
SA node is located in the superior part
Crista terminalis
Between R/L atrium
Remanent of foramen ovale in fetus
Fossa ovalis
Opening in the right to left atrium in fetus
Allows blood to flow from r to l atrium and bypass the lungs
Bypass occurs because placenta provides the gas exchange
Foramen ovale
Fibrous cords connect free edges of AV valves to papillary muscles on floor of ventricles
Chordae tendinae
Elevations of ventricular myocardium
Attach to AV valve leaflets via chordae tendinae
Papillary muscles
What is the combined function of chordae tendinae and papillary muscles
Keep AV valves from prolapsing backward into the atriums when closing during systolic contraction of ventricles
Projection ridges of myocardium
Papillary muscles are specialized
Trabeculae carnae
A single specialized trabeculum that Carrie’s part of the conduction system to the anterior wall of right ventricle
Moderator band
Where is the pulmonary valve
Between the right ventricle and pulmonary trunk
3 semilunar cusps
Forms a pocket like sinus
Do atria or ventricles have thicker walls
Ventricles, they have to pump blood to rest of the body
Left ventricle has more myocardium to send blood through the aorta
Right side blood flow
SVC, IVC, Coronary sinus Right atrium Tricuspid valve Right ventricle Pulmonary valve Pulmonary trunk Pulmonary arteries Lungs
Left side blood flow
Lungs Pulmonary veins Left atrium Bicuspid valve Left ventricle Aortic valve Aorta Systemic circulation
Pulmonary circuit characteristics
Short with low pressure circulation
Systemic circulation characteristics
Long, high friction
More pressure
What is coronary circulation
Blood supply to heart itself
Shortest circulation
Delivered during relaxation
Left ventricle receives most blood supply
Where do coronary arteries stem from
Base of Aorta
What is the coronary sulcus
Left and right coronary arteries encircle the heart
How much of the body’s blood is used for the heart itself
1/20 th
What merging veins form the coronary sinus
Greater cardiac- anterior inter ventricular sulcus
Middle cardiac - posterior inter ventricular sulcus
Small cardiac- inferior margin
Coordinated heart beat is a function of what
Gap junctions
Intrinsic cardiac conduction system
What is the sinoatrial node
Pacemaker of the heart in right atrial wall
What part of the heart depolarizes the fastest
SA node
What is sinus rhythm
75 x/minute
How does impulse spread across the atria of the of the heart?
Via gap junctions to AV node
Where is the atrioventricular node
Lower right atrium in interventricular septum
What is the delay of the AV node
Because?
What does this allow?
.1 second delay
Because fibers are smaller in diameter and have fewer gap junctions
Allows atrial contraction before ventricular contraction
Rate of AV node without SA node
50 bpm
What is the atrioventricular bundle
Bundle of his
In superior interventricular septum
Only electrical connection between atria and ventricles
What are the R/L bundle branches
Two pathways in the interventricular septum that carry impulse towards the apex of the heart
What is the subendocardial conduction network
Purkinje fibers
Complete pathway through the interventricular septum into the apex and ventricular walls
The purkinje fibers are more elaborate on what side
L side
AV bundle and purkinje fibers depolarize at what rate without AV node
30 bpm
Ventricular contraction immediately follows depolarization from apex towards atria
Contraction process takes approximately how long
.22 seconds from initiation at SA node to complete contraction
What system both increase the rate and force of the heartbeat
Sympathetic nervous system
Where in the brain is the cardioacceleratory and cardioinhibitory
Medulla oblongata
Where do sympathetic nerve fibers project
SA node, AV node, bulk of myocardium
Releases norepinephrine
Cardioacceleratory center is the source of what
Sympathetic output of the heart
Cardioinhibitory center is the source of what
Parasympathetic output of the heart
Where do parasympathetic fibers project
Vagus nerve to the SA node and AV node
Release acetylcholine
What is an electrocardiograph
Graphic recording of electric activity
Composite of all action potentials at a given time
Measure voltage differences- 12 leads
What does the P wave represent
Depolarization of SA node and atria
What does QRS complex represent
Ventricular depolarization and atrial depolarization
What does T wave represent
Ventricular repolarization
What does P-R interval represent
Beginning of atrial and ventricular excitation
What does S-T segment represent
Entire ventricular myocardium depolarized
What does Q-T interval represent
Beginning of ventricular depolarization to end of repolarization
What does the first pub-dip sound represent
The closing of AV valves at the beginning of ventricular systole
What does the second lub-dup sound represent
Closing of semilunar valves at the beginning of diastole
What is the pause between sounds
Heart relaxation
What is the order of valves closing
Mitral before tricuspid
Aortic before pulmonary
Where do you listen to aortic valve
R 2nd intercostal space
Where are the pulmonary valve sounds heard
L 2nd intercostal space
Where is the mitral valve heard
Over the heart apex, 5th intercostal space in line with middle clavicle
Where is the tricuspid valve heard
R 5th intercostal space
Air reaching the bronchi is
Warm and cleansed of impurities
Saturated with water vapor
Air passage undergoes how many orders
23
What vessels attach to the left atrium and where are they coming from
L/R superior/inferior pulmonary veins
Coming from lungs to the L atrium
When are the AV valves closed and open
Open during diastole
Closed during systole
When are semilunar valves closed and open
Closed during diastole
Open during systole
What arises from R aortic sinus
Right coronary artery
What arises from L aortic sinus
Left coronary sinus
What are the branches of the R coronary artery
SA node branch
Acute marginal
AV nodal branch
What are the branches of the L coronary artery
Left anterior descending artery
Circumflex
Obtuse marginal
Where does the great cardiac vein run
Runs with left anterior descending and circumflex branch of the left coronary artery
Continues path in coronary sulcus and enlarges to form coronary sinus entering R atrium
Where does the middle cardiac vein run
With posterior descending artery
What is the blood supply to the SA node
Sinoatrial artery that is supplied by the R coronary artery in 60% of people and L coronary artery in 40%
Normal alignment of pulmonic valve
Anterior
Left
Right
Normal alignment of aortic valve
Posterior
Left
Right
Normal alignment of tricuspid valve
Septal
Anterior
Posterior
Normal alignment of mitral valve
Posterior
Anterior