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113 Cards in this Set
- Front
- Back
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Name the 4 functions of the heart
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1. Generating blood pressure
2. Routing blood (separates pulmonary and systemic circulation) 3. Ensures one-way blood flow 4. Regulating blood supply (adjusts to metabolic changes like exercise / rest) |
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What is the mediastinum?
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heart, trachea, esophogus
midline partition structures |
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Pericardium
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double layered, closed sac that encloses the heart
aka pericardial sac tough, fibrous pericardium and thin serous pericardium |
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What is the outer layer of the heart?
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parietal pericardium
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What is the inner lining of the heart?
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visceral pericardium
aka epicardium |
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Where is the pericardial cavity and what is it filled with?
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between the parietal pericardium and the visceral pericardium and it's filled with pericardial fluid
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What is pericarditis?
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inflammation of serous membrane pericardium
pain similar to a heart attack fluid can build up in pericardial sac |
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What is cardiac tamponade?
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large amount of fluid in pericardial sac.
can occur due to rupture from myocardial infarction, trauma, tumor growth or radiation therapy |
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What are the 3 layers to the heart wall?
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1. epicardium (visceral pericardium
2. myocardium (middle layer) 3. endocardium |
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Describe the epicardium
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thin serous membrane on outer surface of the heart wall
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Describe the myocardium?
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thick middle layer comprised of smooth muscle cells
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Describe the endocardium?
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simple squamous epithelium over a layer of connective tissue.
allows the blood to move smoothly and easily |
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What are the pectinate muscles?
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mucular ridges in both auricles and wall of right atria
(means comb shaped) |
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What is the crista terminalis?
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separates the pectinate muscles from the larger, smoother portions of atrial wall
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What are the trabeculae (beams) carnae (flesh)?
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large muscular ridges on the inside of the ventricles
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What's another term for atria?
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auricles
(ears) |
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How many chambers are there in the heart?
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4
2 atria 2 ventricles |
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What are the 2 main veins going from body into the right atrium?
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superior vena cava
inferior vena cava |
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How many pulmonary veins are there going from the lungs to the left atrium?
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4 pulmonary veins
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What is the main artery connected to the heart?
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aorta
carries blood from the left ventricle to systemic circulation (body) |
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What's the other main artery (besides aorta) in the heart?
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pulmonary trunk
carries blood from the right ventricle to the lungs |
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What is the Coronary sulcus?
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crown /ditch
separates the atria from the ventricles separates the right and left ventricles |
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Where do the arteries that supply the heart with blood lie?
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coronary sulcus
interventricular sulci |
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Explain how the heart gets the blood it needs to pump
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right and left coronary arteries exit the aorta right above where the aorta leaves the heart.
left marginal artery branches off the left coronary artery to supply left ventricle right marginal artery branches off right coronary artery to supply the right ventricle supplies heart with blood from these arteries that lie in the coronary sulcus left anterior interventricular artery lies in the anterior interventricular sulcus to supply blood as well circumflex artery covers the posterior side of the heart posterior interventricular artery supplies the posterior and inferior heart |
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what is an anastomoses?
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direct connections between arterial branches
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What are the 2 sides veins that empty into coronary sinus that flows into the right atrium?
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left side - great cardiac vein
right side- small cardiac vein |
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What are the 3 main openings in the right atrium?
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1. superior vena cava
2. inferior vena cava 3. coronary sinus |
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What are the 4 openings of the left atrium?
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4 pulmonary veins from the lungs
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What is the interatrial septum?
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separates the 2 atria
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What openings do the ventricles have?
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opening with atria
Right ventricle opens to pulmonary trunk Left ventricle opens to aorta |
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what artery covers the posterior of the heart?
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circumflex artery
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Which side is the tricuspid valve?
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Right side
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Which side is in the bicuspid valve?
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Left side
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Where is the coronary sulcus?
What lies in it? |
between the right atrium and right ventricle
Right coronary artery |
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Where is the anterior interventricular sulcus?
What lies in it? |
Between the right and left ventricles on the anterior side of heart
Great cardiac vein and anterior interventricular artery |
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Where is the coronary sinus located?
Where does it empty into? |
posterior in halfway part
Right atrium |
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What are the 3 major openings of the Right Atrium?
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superior vena cava
inferior vena cava coronary sinus |
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What are the 4 openings of the left atrium?
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4 pulmonary veins from the lungs
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What's another name for the bicuspid valve?
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mitral valve
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What are papillary muscles?
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Heart strings
attached to valve cusps in each ventricle. These muscles contract when the ventricle contracts |
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What are the semilunar valves?
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aortic and pulmonary
keeps blood moving in one direction |
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I am a little drop of blood in the coronary sinus. Explain my trip through the heart and back to this spot...
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coronary artery flows into right atrium
thru the tricuspid valve into the right ventricle thru the pulmonary semilunar valve to the pulmonary trunk take the pulmonary arteries to the lungs Head back to the heart via the pulmonary veins into the left atrium thru the mitral valve into the left ventricle thru the aortic semilunar valve to the aorta into the body to end up in the superior or inferior vena cava OR to the heart and back to the coronary sinus whew. |
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do veins carry Oxygen rich or CO2 blood?
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veins carry oxygenated blood
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Do arteries carry O2 blood or CO2 blood?
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CO2 blood
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what is a myocardial infarction?
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prolonged lack of blood flow to caridac muscle resulting in cell damage and death.
arises from atherosclerotic lesions (plaque) |
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What is angina pectoris?
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chest pain
reduced blood supply to cardiac muscle treated with nitroglycerin tablets which dilate vessels |
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Describe the 'skeleton' of the heart
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fibrous conn. tissue forms fibrous rings around the atrioventricular and semilunar valves.
provides support, electrical insulation and muscle attachment site |
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Describe the physical characteristics of cardiac muscle cells
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elongated branching cells
striated 1-2 central nuclei actin / myosin myofilaments |
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Describe the Ca2+ channels and how it effects heart muscle function
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smooth sarcoplasmic reticulum is in close contact with the T tubules, but the T tubules are loosely arranged and therefore there is a slower onset and prolonged contraction phase
Depolarization is less efficient and Ca2+ has further to travel to get to the actin myofilaments |
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What provides the energy for cardiac muscle contraction?
What does that lead to? |
ATP
needs O2 and so cardiac muscle cells are full of mitochondria that provide oxidative metabolism |
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What is the conduction system of the heart consist of?
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2 nodes
sinoatrial SA (pacemaker) atrioventricular AV atrioventricular bundle (has right and left branches) |
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Describe an a.p. process in the heart
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a.p. originates in SA node and travels to AV node
a.p. continues to atrioventricular bundle and branches into right and left Purkinje fibers distribute a.p. to ventricular walls |
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Where is the atrioventricular bundle located?
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interventricular septum
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Go thru the process of depolarization for a cardiac a.p.
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DEPOLARIZATION PHASE:
Voltage gated Na+ channels open Voltage gated K+ channels close Voltage gated Ca2+ channels begin to open EARLY REPOLARIZATION & PLATEAU PHASE Voltage gated Na+ channels close Some voltage gated K+channels open, causing early repolarization Voltage gated Ca2+ channels are open, producing the plateau by further slowing repolarization FINAL REPOLARIZATION PHASE Voltage gated Ca2+ channels close Lots of voltage gated K+ open early repolarization where some of the Na+, Ca2+ channels close, Na+ flowing in slows and some K+ starts to go out plateau phase Ca2+ channels open and slows the repolarization |
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what does autorhythmicity mean?
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cardiac muscle stimulates itself to contract in regular intervals
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What is the prepotential and what does it do?
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spontaneously developing local potential from the SA node.
small number of Na+ channels are open voltage gated K+ channels are closing from previous a.p.'s repolarization phase Voltage gated Ca2+ channels are beginning to open |
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What is an ectopic focus?
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any other part of the heart besides SA node generating a heartbeat.
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on an EKG, what does the P wave represent?
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a.p. that causes depolarization of the atrial myocardium
onset of atrial contraction |
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Why is a prolonged refractory period a good thing in cardiac muscles?
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keeps beating rhythmic and prevents tetanic contraction
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What does the QRS complex on an ECG represent?
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ventricular depolarization and signals the onset of ventricular contraction
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What does the T wave represent on an ECG?
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repolarization of the ventricles
precedes ventricular relaxation |
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What is the PR interval and what's happening?
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0.16 seconds
atria contract and begin to relax ventricles begin to depolarize at the end of it |
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What is the QT interval and what's happening?
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0.36 seconds
ventricles contract and begin to relax |
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What does a prolonged PR interval indicate?
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1. delay in ap conduction thru atrial muscle because of damage (ischemia)
2. delay in ap conduction thru atrial muscle because of a dialated atrium 3. delay in ap conduction thru the AV node and bundle due to ischemia, compression or necrosis of the AV node or bundle |
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What does an unusually long QT interval indicate?
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abnormal conduction of ap's thru the ventricles (from myocardial infarction or abnormally enlarged right or left ventricle)
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What is atrial fibrillation?
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no p waves
normal QRS irregular timing ventricles constantly stimulated by atria reduced pumping effectiveness and filling time |
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What causes atrial fibrillation?
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ectopic a.p.'s in atria
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What is ventricular fibrillation?
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No QRS complex wave
no rhythmic contraction of the myocardium many patches of asynchronously contracting ventricular muscle |
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What causes ventricular fibrillation?
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ectopic a.p.'s in ventricles
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What is Tachycardia?
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Heart rate in excess of 100 bpm
could be caused by elevated body temp. excessive sympathetic stimulation toxic conditions |
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What is Bradycardia?40-60
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Heart rate less than 60 bpm
Elevated stroke volume in athletes excessive vagal stimulation carotid sinus syndrome |
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What is sinus arrhythmia?
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Heart rate varies 5% during respiratory cycle and up to 30% in deep respiration
ischemia, inflammation cardiac failure |
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What are the corresponding bpm of:
SA Node AV Node AV bundle |
SA 70-80
AV 40-60 AV bundle 30 |
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Describe the cardiac cycle
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SYSTOLE--isovolumic contraction
SYSTOLE--ejection DIASTOLE--isovolumic relaxation DIASTOLE--passive ventricular filling DIASTOLE--active ventricular filling |
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What is blood pressure a measure of?
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pressure in aorta rather than left ventricle
systolic average is 120 mm Hg diastolic average is 80 mm Hg |
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What is MAP?
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mean arterial blood pressure
Cardiac Output x Peripheral resistance |
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What is cardiac output CO?
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amount of blood pumped by heart per minute
Heart Rate x Stroke Volume (BPM) (end diastolic- end sys) vol. vol. |
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What is Peripheral resistance PR?
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total resistance against which heart beats
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What does exercise do to end-diastolic volume?
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It increases the volume because venous return increases
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What does exercise do to end systolic volume?
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It decreases it because the harder contractions pump more out
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What is the approximate CO of the heart at rest?
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HR= 72 bpm
SV= 70 mL 72 x 70= 5040 mL/min |
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What is the CO of the heart during exercise?
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HR= 190 bpm
SV = 115 mL/min 190 x 115 = 21,850 mL/min |
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What is the cardiac reserve and what does it indicate?
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the difference between the resting heart CO and the maximum CO during exercise.
The greater the number of this reserve the greater is the individual's capacity for doing exercise |
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Which type of regulation of the heart utilizes hormones and neurons?
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Extrinsic regulation
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What is intrinsic regulation of the heart?
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Normal heart function.
No neurons or hormones involved. |
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What is preload?
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extent to which ventricular walls stretch
think back to skeletal muscles. For the greatest contraction the muscles are stretched to the optimum length for greatest force. cardiac muscles are different. They create stronger contractions by stretching of the ventricular walls to a big "preload" length. |
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What is Starling's law of the heart?
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relationship between preload and stroke volume.
The bigger the preload stretch the larger the stroke volume. |
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What is afterload?
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pressure it takes for ventricles to push the blood into the aorta.
This doesn't change very much |
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What type of regulation are preload, Starlings law and afterload a part of?
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Intrinsic regulation
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Do parasympathetic or sympathetic nervese play more of a role in extrinsic regulation?
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Sympathetic
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What is extrinsic regulation responsible for?
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blood pressure
blood O2 levels blood CO2 levels blood pH levels |
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What is parasympathetic extrinsic regulation responsible for?
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It plays an inhibitory role through the vagus nerve
decreases H.R. |
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How does parasympathetic extrinsic regulation decrease HR?
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acetycholine binds to ligand gated channels making the cardiac membrane to become more permeable to K+ causing hyperpolarized membrane (takes longer to depolarize so action potentials are fewer)
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What do the postganglionic sympathetic nerve fibers innervate to stimulate the heart?
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SA and AV nodes
coronary vessels atrial and ventricular myocardium |
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What does stimulation of the sympathetic extrinsic regulation do?
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increases the HR and force of muscular contraction
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What can happen if sympathetic stimulation causes the heart rate to increase too much?
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stroke volume can go down because there is not enough time for ventricular filling (end diastole volume is low)
metabolites can increase and cause a decrease in strength of contractions |
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To what degree does sympathetic stimulation effect the regulation of contraction force in a person at rest?
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it provides 20% more oopmh to contraction force by stimulating the ventricular myocardium
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How does norepinephrine increase the heart rate and degree of cardiac muscle depolarization?
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norepinephrine combines with B-adrenergic receptors, causeing a Gprotein-mediated synthesis and accumulation of cAMP in the cytoplasm of cardiac muscle cells.
Cyclic AMP increases the permeability of the plasma membrane to Ca2+ |
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What hormones dramatically influence the pumping effectiveness of the heart?
Where do they come from? Why? |
epinephrine and norepi
adrenal medulla in response to exercise, stress, or extreme excitement |
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What is the Baroreceptor reflex?
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detectors feeling changes to blood pressure (stretch receptors)
inside the walls of certain large arteries (aorta and internal carotid, i.e.) They have afferent nerves that extend through the glossopharangeal nerve (IX) and vagus (X) to the cardioregulatory center (medulla oblongata) |
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Describe the heart is regulated from baroreceptor signals
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sensory neurons carry ap's from baroreceptors to cardioregulatory center
cardioregulatory center regulates parasympathetic ap's (decreases hr) thru vagus nerve cardioregulatory center regulates sympathetic ap's thru cardiac nerves (increases hr and sv) cardioregulatory center sends ap's thru the sympathetic neurons to adrenal medulla, which then releases epi and norepi (increase the hr and sv) |
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Are the frequency of ap's increased or decreased when blood pressure increases in the carotid artery?
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increased blood pressure causes the arteries to stretch thereby sending more frequent ap's from the baroreceptors
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What does increased blood pressure do to sympathetic and parasympathetic stimulation?
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increased blood pressure decreases sympathetic stimulation and increases parasympathetic stimulation
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What does decreased blood pressure do to sympathetic and parasympathetic stimulation?
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Decreased blood pressure decreases parasympathetic stimulation and increases sympathetic stimulation
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What are chemoreceptor reflexes?
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regulate
pH CO2 |
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What happens if the medulla oblongota chemoreceptors detect a drop in blood pH and a rise in CO2?
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decrease parasympathetic stimulation and increase sympathetic stimulation
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Where are chemoreceptors sensitive to blood oxygen levels found?
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carotid and aortic bodies near brain and heart
have more impact of regulating respiration and vasoconstriction than hr |
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What are the important ions for heart function?
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K+, Na+, Ca2+
Na+ levels stay very constant in the heart muscles |
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What happens if there is an excess of K+ in cardiac tissue?
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HR decreases
SV decreases only partially depolarizes membrane so ap's decrease and ectopic ap's occur causing fibrillation |
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What happens if there is a decrease in extracellular K+?
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HR decreases
resting membrane potential is hyperpolarized so it takes longer for the membrane to get to threshold |
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What happens if there is an excess of extracellular Ca2+
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cardiac contraction increases
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What happens if blood Ca2+ levels are low?
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HR increases (more Na+ channels are opening, so more depolarizations)
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What does getting old do to your heart?
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hypertrophy of left ventricle due to increased aortic pressure and stiffening of cardiac muscle
decrease in maximum heart rate tissue becomes less flexible electric system gets a little faulty (SA nodes decrease) coronary heart disease |
