Chapte 18 Cardiovascular--Heart Flashcards
Why is the heart considered a transport system pump?
Uses blood as the transport medium Pumps oxygen Nutrients Wastes Into blood vessels that service cells
Mediastinum
Medial cavity of the thorax
Pericardium
Double walled sac around heart
Fibrous pericardium
Superficial part of the pericardium
Serious pericardium
Serous membrane
Parietal layer
Lines the internal surface of the fibrous pericardium
Visceral layer
Also called epicardium
Heart surface
Pericardial cavity
Contains the serous fluid
3 layers of the heart wall
Epicardium
Myocardium
Endocardium
What is the epicardium
Visceral layer of the serous pericardium
What is the myocardium
Cardiac muscle
What function does the myocardium have?
Contracts
Fibrous skeleton
Reinforces the myocardium
Anchors the cardiac muscle fibers
What is the endocardium?
Sheet of endothelium that rests on a connective tissue layer
Lines the heart chambers
Covers the fibrous skeleton of the valves
What is the structure of the heart chambers?
2 superior atria
2 inferior ventricles
Interatrial septum
Inter ventricular septum
Coronary sulcus
Encircles the junction of the atria and ventricles
Anterior interventricular sulcus
Cradles the anterior interventricular artery
Posterior interventricular sulcus
Landmark of of the postinferior surface
Auricles
Increase the atrial volume
Pectinate muscles
Bundles of muscle tissue
Crista terminalis
C-shaped ridge
Separates the anterior/posterior regions of the right atrium
Fossa ovalis
Foremen ovale existed in the fetal heart
Blood pathway
Right atrium via 3 veins
Superior vena cava
Inferior vena cava
Coronary sinus
Superior vena cava
Returns blood from the body regions superior to the diaphragm
Inferior vena cava
Returns blood from body regions below the diaphragm
Coronary sinus
Collects blood draining from the myocardium
Four pulmonary veinstransport blood from the lungs back to the heart
Enter the left atrium
Trabeculae carneae
Irregular ridges along the internal walls of the ventricular chambers
What is the role of the ventricles?
Pumps out blood
Where does the right ventricle pump blood?
Pulmonary trunk
Pulmonary trunk
Routes blood to the lungs where gas exchange occurs
What function does the left ventricle have?
Ejects blood into the aorta
What is the aorta
Largest artery in the body!
What is a pulmonary circuit?
Blood vessels that carry blood to and from the the lungs
What is systemic circuit
Blood vessels that carry the blood supply to and for all body tissues
Pathway of pulmonary circulation
Blood returns from the body poorly oxygenated
Enters the right atrium
Right ventricle
Pumps to the lungs via pulmonary trunk
Unloads Carbon Dioxide and picks up Oxygen
Oxygenated blood ferried by the pulmonary veins to the left side of the heart.
Systemic circulation
Oxygenated blood leaves the lungs
Returns to the left atrium
Passes to the left ventricle
Pumps into the aorta
Transports by smaller systemic arteries to the blood tissues where gasses and nutrients are exchanged across capillary walls
Deoxygenated blood returns through the systemic veins to right side of the heart
Enters through the superior and inferior Venae Cava
Ventricles have 2 unequal loads
Pulmonary circuit served by the right ventricle, is a short, low pressure circulation
Systemic circuit–left ventricle–takes a long pathway through the body
Coronary circulation
Functional blood supply of the heart Shortest circulation Right and left coronary arteries Comes from the base of the aorta Circles the heart in the coronary sulcus
Left coronary artery
Left side of the heart then divides into branches
Anterior interventricular artery
Circumflex artery
Anterior interventricular artery does what function?
Supplies blood interventricular septum and anterior walls of BOTH ventricles
Circumflex artery does what function?
Supplies the blood to the left atrium and posterior walls of the left ventricle
Right coronary artery has 2 branches
Right marginal artery
Posterior interventricular artery
Posterior interventricular artery runs to the heart apex
Supplies the posterior ventricular walls
Near the apex, artery merges with the interventricular artery
runs to the heart apex
Supplies the posterior ventricular walls
Near the apex, artery merges with the interventricular artery
Additional routes for blood delivery
Many anastomoses (junction) among the coronary arterial branches
Cardiac veins
Venous blood collected after it passes through the capillary beds of the myocardium.
Coronary sinus
Empties blood into the right atrium
Coronary sinus has 3 parts
Great cardiac vein
Middle and small cardiac vein
Anterior cardiac veins empty where?
Right atrium anteriorly
Angina pectoris
Thoracic pain caused by a defiency in blood delivery to the myocardium.
Can be caused from stress-induced spasms of the coronary arteries or increased physical demands from the heart
Myocardial infarction (MI)
Heart attack
Atrioventricular valves (AV)
Prevent back flow into the atria
3 flexible cusps
Right AV valve (tricuspid)
Left AV valve (bicuspid)
2 flaps
Mitral valve
Chordae tendineae
Heart strings that anchor the cusps to the papillary muscles protruding to the ventricular walls
Function of the chordeae tendineae and papillary muscles
When the ventricles contract, the force of blood against the valves causing the valves to close.
Chordae tendineae and papillary muscles…
Anchor the valve flaps in closed position
When the heart is relaxed, the AV valve will…
Blood flows into atria then through the open AV valves into ventricles
Wen ventricles contract…
Blood compresses
Intraventricular pressure increases
Forces blood against the valve flap
Flaps close valve
Aortic and pulmonary valves
Guard the bases of the large arteries issuing from the ventricles
Prevent back flow
Pulmonary valve is also known as what?
Semilunar valve
SL
What function does the SL valve perform?
Fills the cusps
Closes the valves
What is valvular stenosis?
Stiffening of the valve flaps and constriction of opening
Results in the heart working harder
Cardiac muscle
Skeletal muscle Striated Contracts by sliding filament Short Fat Branched Interconnected
Intercellular spaces are filled with…
Endomysium
Capillaries
Intercalated disks
Contain desmosomes and gap junctions
Function of the desmosomes
Prevent adjacent cells from separating during contraction
Gap junction will…
Allow ions to pass from cell to cell
Transmit current across the heart
Functional syncytium
When the myocardium behaves as single coordinated units
Lg michrochondria acct for 25-35%of what
Cardiac cells
Automaticicity
Cells that initiate their own depolarization for the heart
Organ vs motor unit contraction
Skeletal muscle stimulate and contract at the same time
Impulses don’t spread from cell to cell
Cardiac muscles work as a unit or not at all
Cardiac refractory period lasts how long?
250 ms
Intrinsic cardiac conduction system
No contractile cardiac cells initiate and distribute impulses throughout the heart
Depolorizes
Autorhythmic cells
Pacemaker of the heart
