Chapter 21: Cardiovascular system and Heart Flashcards
describe the cardiovascular system (4)
Vital for survival
Carries oxygen & nutrients to tissues
Carries wastes away from tissues
Closed system
the cardiovascular system is a double circuit. What are the two circuits? describe them
- ) Pulmonary
- Heart to lungs & back
- Oxygenates blood - ) Systemic
- Heart to body & back
- Delivers oxygen to tissues
describe the structure of the heart (5)
- Cone shaped
- Inside pericardial cavity
- inside mediastinum
- apex tipped toward the inferior and left
- base superior
describe the membranes of the heart
Pericardium -double serous membrane with fibrous coat -made of several layers Parietal pericardium -outer layer of sac -Fibrous and areolar layer Epicardium -A.k.a. visceral pericardium -inner layer of sac -Adheres to the heart wall
where is the pericardial cavity located and what does it contain?
located between membrane layers and contains serous fluid
what three things are in the wall of the heart/ make up the wall of the heart?
Epicardium, Myocardium, Endocardium
describe the epicardium (2)
visceral pericardium
functions as protective outer layer
describe the myocardium (3)
middle layer
responsible for contractions
made of cardiac muscle
describe the endocardium (3)
inner layer
lines & protects chambers & valves
continuous with endothelium of heart blood vessels
describe cardiac muscle tissue (5)
striated aerobic respiration short T-tubules autorhythmic connected mechanically & chemically -intercalated discs -gap junctions
how many chambers are there in the heart? what are they
4 chambers
- 2 atria (right and left)
- 2 ventricles (right and left)
describe the atria (3)
superior chambers
receive blood from veins
have auricles (flaps where blood pools)
describe the ventricles (2)
inferior chambers
force blood out to arteries
what are the structural differences between the right and left ventricles?
Left thicker & stronger
Right goes only to lungs
Left is round
Right pouch shaped
describe the two atrioventricular valves
Tricuspid valve -aka right AV valve -at right atrioventricular orifice -open when atrial force is greater & close when -ventricular force is greater -3 cusps Bicuspid (mitral) valve -aka left AV valve -at left atrioventricular orifice -2 cusps
what are the “heart strings” called? describe them
Chordae Tendonae
- hold valves in place
- attached to cusps on ventricle side
what do the chordae tendonae prevent?
cusps from collapsing into atria when valve is closed
Backflow of blood
describe the papillary muscles (2)
small bundles of muscles
- Attach to the chordae tendonae
- when valves close, these muscles contract & tighten cords
scaffolding on interior walls are known as what?
Trabeculae Carneae
semilunar valves are located where?
what are the two?
- between a ventricle and an artery
- Pulmonary and Aortic
describe the pulmonary valve
right
at entrance to pulmonary trunk
opens when right ventricle contracts
describe the aortic valve
right
at entrance to pulmonary trunk
opens when right ventricle contracts
describe the path that blood takes through the heart
slide 15 and 16
what does coronary circulation do?
supplies the heart tissues with blood
what happens if the coronary circulation gets blocked?
blockage can result in heart tissue dying
where do the coronary arteries branch off?
Branch directly off of the aorta as it emerges
what are the two branches off the right coronary artery?
posterior interventricular artery
marginal artery
what are two branches off the left coronary artery?
circumflex artery
anterior interventricular artery
what do cardiac veins do?
drain myocardium
travel with arteries
what are the three cardiac veins?
What is the other cardiac vein called and what does it empty into?
Great
Middle
Small
-Coronary sinus: empties into right atrium
what is the contractile phase; chamber empties
systole
what is the relaxation phase; chambers fill
diastole
describe what happens when your heart makes the “Lub” and “Dup” sounds
“Lub” = AV valves close “Dup” = semi-lunar valves close
Heart beat is enabled by what 2 things? describe them
- ) nodal cells
- specialized muscle cells that conduct action potentials - ) conducting fibers
- distributes stimulus to myocardium
true or false: AP’s move down heart, causing it to contract unevenly
true
*atria contract before ventricles
what are the 5 steps in the conduction system of the heart?
- ) SA node activity and atrial activation begin
- ) Stimulus spreads across the atrial surfaces and reaches the AV node
- ) There is a 100-msec delay at the AV node. Atrial contraction begins
- ) The impulse travels along the interventricular septum within the AV bundle and the bundle branches to the Purkinje fibers and, via the the moderator band, to the papillary muscles of the right ventricle
- ) The impulse is distributed by the Purkinje fibers and relayed throughout the ventricular myocardium. Atrial contraction is completed, and ventricular contraction begins
describe the SA (sinoatrial) node (3)
pacemaker
spontaneously depolarizes
At the back wall of right atrium
describe the AV (atrioventricular) node (2)
- where 4 chambers meet
- Signal transmitted to AV (atrioventricular) node through internodal pathways
the AV (atrioventricular) bundle….
transmits down interventricular septum
describe bundle branches (3)
Branch off the AV bundle
Moves further down the septum
one supplies each ventricle
describe Purkinje Fibers (2)
- reflect up external wall of ventricle
- extend into papillary muscles
slide 27 and 28
because I’m lazy and don’t know how to make these cards really into flashcards
