Heart & Thoracic Anatomy Flashcards
Purpose of the CV system
Delivers O2 + nutrients to tissues
Removes waste products
Where is the heart located?
In the mediastinum
Purpose of the pericardium
Surrounds + protects the heart
Fuses with the diaphragm (so heart stays in place)
Relationship between diaphragm and heart
When diaphragm moves while breathing, heart moves slightly –> helps BF through heart
Where does the SVC carry blood?
To heart from upper body
Where does the IVC carry blood?
To heart from lower body
Sections of the mediastinum (x4)
Anterior, middle, posterior and superior
What is in the anterior mediastinum?
Thymus gland
What is in the middle mediastinum?
Heart, asc. aorta, pulmonary trunk, phrenic nerves
What is in the posterior mediastinum?
Descending aorta, esophagus, vagus n. and thoracic duct
What is in the superior mediastinum?
Aortic arch, esophagus & trachea
Characteristics of the thymus gland
Bigger in childhood vs adulthood (atrophy occurs)
Development of T cells in immune system before birth + during childhood
Purpose of auricles
Allows the L and R atriums to increase blood capacity
What is the coronary sulcus?
Groove between atria & ventricles
What are the interventricular sulci?
Two of them - ant. and post.
Between right and left ventricles
Where is the right coronary artery found?
Coronary sulcus
What does the R coronary a. branch off to?
Posterior interventricular a. and R marginal a.
What does the L coronary a. branch off to?
Circumflex a. (coronary sulcus)
L ant. desc. a. (LAD) interventricular a.
What do the cardiac a. do?
Bring O2 and nutrients –> cardiac tissue
Purpose of coronary veins
Removal of CO2 and waste
Which coronary veins drains into the coronary sinus then RA? (x3)
Small cardiac
Middle cardiac
Great cardiac
Which vein drains directly into the RA?
Anterior cardiac vein
Where is the small cardiac vein found?
Coronary sulcus
Where is the middle cardiac vein found?
Post. interv. s.
Where is the great cardiac vein found?
Ant. interv. s.
Layers of the pericardium
Fibrous pericardium
Serous pericardium
Characteristics of fibrous pericardium
Dense, irregular CT
Protects + anchors heart (connected to diaphragm + prevents heart over-stretching)
Characteristics of serous pericardium
Parietal layer - secretes serous fluid (lines the cavity)
Visceral layer (aka epicardium) - secretes serous fluids + adheres to heart wall, lines the heart
Purpose of the pericardial cavity
Space between the 2 layers of pericardium
Both layers secrete serous fluid into here
Lubricates the heart + prevents friction
Layers of the heart wall
Epicardium
Myocardium: has specialized cardiac muscle tissue
Endocardium: lines heart chambers: smooth lining = less friction
Cause of myocarditis
Viral infection, radiation, meds
Cause of endocarditis
Often bacterial –> affects heart valves
Why are atrial walls thin?
Don’t need a lot of muscle to deliver blood –> ventricle
Why are ventricle walls thick?
Need to move blood from ventricles –> body tissues under a high pressure
Why is the LV wall thicker than RV?
LV has to work harder to get blood to tissues (greater distance, high pressure + resistance to BF)
Purpose of fibrous rings
Structural foundation
Maintains valve diameter
Attachment site for muscle fibers
Electrically separates the atria from the ventricles
Where are AV valves located?
Between atria & ventricles
Where are SL valves located?
Between ventricles and great vessels
AV valves and chordae tendinae
Cusps of AV valves have chord tendinae –> connect to papillary muscles
What is a subvalvular apparatus?
Chordae tendinae + papillary muscles
Open + close AV valves
What are papillary muscles made up of?
Trabeculae carnae: bundles of cardiac muscle fibers
Purpose of heart valves
Ensure one way direction of blood flow
What is ventricular diastole? Relation to AV valves
Blood drains from atria –> ventricles
AV valves are relaxed
What do the AV valves do during ventricular systole?
They close –> taut chordae tendinae
What is AV valve prolapse?
When cusps open into atria during ventricular contraction
When do SL valves open?
During ventricular contraction –> increased pressure in the ventricles
Pushes blood against the SL valves
Blood is ejected into the great vessels
When do the SL valves close?
During ventricular diastole –> blood flows back into ventricles
Blood catches behind valve cusps –> closes and the back pressure from the blood on the valves keeps them closed
Heart valve stenosis
Narrow heart valve –> constricted BF
Due to: congenital defect, scarring + age
Mitral valve prolapse
Causes: genetic disorder & CT damage
Why don’t venous entry points have valves?
When atria contracts, the muscle compresses the weak walls of the openings –> causes them to almost collapse
