Chapter 17 Flashcards
Pulmonary circulation
blood goes from the heart to the lungs
Systemic circulation
blood goes from the heart to the rest of the body
What does the heart sit in
a pericardial sac with pericardial fluid
What are the layers of the heart wall
epicardium, myocardium, endocardium
What is the epicardium made of
simple squamous epithelium and areolar/adipose loose connective tissue (deep to the epithelium)
Where are auto-rhythmic cells found in the heart
the myocardium
what is the myocardium made of and what does it do
fibrous connective tissue that reinforces muscle, gives collagen support, and separates the muscle between atria and ventricles
What is the endocardium made of
simple squamous epithelium that is continuous with the lining of blood vessels and dense irregular connective tissue (deep to the epithelium)
What do valves do
ensure that blood only flows in one direction, in and out of the ventricles
what do AV valves have that SL valves don’t
chordae tendonae
Stenosis
narrowed valve
regurgitant
valve that opens but doesn’t fully close allowing blood to flow backwards
Where is stenosis most commonly found
aorta
Where is regurgitant most commonly found
mitral valve
What are murmurs caused by
abnormally functioning valves
Atria
made of thin myocardium and acts as receiving chambers for blood
Auricles
act as expansion chambers
Interatrial septum
separation between the atrias
Where is the pectinate muscle found
atria
Right atria
receives deoxygenated blood from the body through the superior/inferior vena cava and coronary sinus
Left atria
receives oxygenated blood from the lungs through the right and left pulmonary veins
Ventricles
made of thick myocardium, work to pump blood
What does a thicker myocardium mean
more pressure
Interventricular septum
separation between the ventricles
trabeculae carnae
beams of muscle in the ventricles
Where are papillary muscles found
ventricles
Chordae tendonae
rope like chords that connect the atrium and the ventricle
Right ventricle
pump blood to the lungs through the pulmonary trunk, which splits into right and left arteries
Left ventricle
pump blood to the body through the aorta
Do the right and left sides of the heart have equal volume
yes
Do the right and left sides of the heart have equal pressure
No, left has more
Coronary circulation
the circulation of the blood in the veins and arteries that supply the heart
Pathway of the heart’s conduction system
sinoatrial node, atrioventricular node, AV bundle, right and left bundle branches, Purkinje fibers
What happens during the P wave
atrial depolarization through Na+ flowing into the atrium
What happens during QRS wave
ventricle depolarization through Na+ flow into the ventricles and atrial repolarization
What happens during T wave
ventricle repolarization through K+ flow out of ventricle cells
Nodal/junctional rhythm (4)
no P wave, SA node is not functioning, AV node is controlling the rate, paced slow
Heart block (3)
more P waves than QRS waves, decrease in the connection between atria and ventricles, very slow
Bundle block (3)
one of the bundle branches is not communication, the message isn’t sent to ventricles, QRS gets wide
Ventricular fibrillation (2)
all parts of the heart are randomly depolarizing and contracting, death
What is defibrillation
a big jolt in electricity that depolarizes the whole heart, stopping depolarization, hoping that the SA node takes over again like it is supposed to
Current myocardial infraction (MI)
elevated ST segment due to a lack of O2, blood flow, ATP, and correct ion concentration
Old MI with damage
has deep Q waves because action potentials move away or around dead parts of the heart
Ventricular filling
mid to late diastole, AV valves open, SL valves closed
Ventricular systole
ventricles start contracting, isovolumetric contraction occurs to build up pressure, AV valves close, SL valves close, S1
Ventricular ejection
blood is pumped out of the ventricle, AV valves close, SL valves open due to the higher ventricular pressure
Early diastole
isovolumetric relaxation, pressure in ventricles fall, AV valves close, SL valves close, S2
End diastolic volume (EDV)
full volume of 120
End systolic volume (ESV)
partially empties volume to 50
Stroke volume (SV)
the volume moved by the left ventricle per beat
SV=EDV-ESV
Cardiac output (CO)
volume of blood pumped per minute, SV*HR
What does homeostasis do for the heart
constantly adapting CO for the body’s needs
What is the primary way of adjusting and changing CO
heart rate
What is the main way that heart rate is effected
through the autonomic nervous system
Parasympathetic system secretion
ACh, through the vagus nerve, output from the cardio-inhibitory center in the brainstem
Sympathetic system secretion
NE, by cardiac sympathetic nerves, output from the cardio-acceleratory center in the brainstem
Proprioceptors
sensing movement to stimulate sympathetic increase in heart rate
Baroreceptors
measure pressure, decline causes stimulation of an increase in heart rate to attempt to raise pressure
What do EPI, NE, and thyroid hormones do to heart rate
increase when hr increases
What drugs increase hr
caffeine and nicotine
What drugs decrease hr
beta blockers
what does an increase in Ca++ cause
increase in hr
what does a decrease in K+ cause
decrease in hr
What does stretching of the heart cause
increased pressure
What is the heart constantly adjusting
how hard/how much the heart is pumping
