Term
| Where is cardiac muscle found? |
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Definition
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Term
| What are the 3 layers of the heart wall? |
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Definition
endocardium
mycardium
epicardium |
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Term
| endothelium underlain by loose CT |
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Definition
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Term
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Definition
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Term
| Denser CT covered with mesothelium |
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Definition
| epicardium AKA visceral pericardium |
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Term
| the cotraction of cardiac muscle has a |
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Definition
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Term
| the intercellular spaces in the cardiac muscle is due to |
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Definition
| the capillaries within the heart muscle |
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Term
| small dense granules found in atrial cardiac muscle that decrease blood volume and pressure by getting the kidneys to excrete sodium and water in urine |
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Definition
| atrial natriuretic peptide |
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Term
| A type of modified cardiac muscle fiber , that has sparse, peripherally located myofilaments, part of the conducting system, amd located between ventricular endocardium and contractile muscle |
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Definition
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Term
| Where are organelles collected in cardiac muscle? |
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Definition
| they are collected at nuclear poles |
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Term
| Where are intercalated disks found in cardiac muscle? |
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Definition
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Term
Patch like junctions anchored with actin filaments.
they are similar to zonula adherens but they make a patch net not a belt |
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Definition
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Term
| Spot-like junction, anchored with desmin intermediate filaments |
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Definition
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Term
| Allows ions to pass, transmits contractile stimulus |
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Definition
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Term
| where are the t-tubules found in cardiac muscle |
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Definition
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Term
| Are triads found in cardiac muscle? |
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Definition
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Term
| Describe Cardiac development |
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Definition
Mesoderm anterior to embryo’s cranial region aggregates to form angiogenic cell clusters and differentiating cardiomyoblasts.
It initially forms in front of the head then fold into the chest |
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Term
| The type of muscle fiber found in cardiac muscle |
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Definition
| Type I, oxidative, Cardiac Beta, |
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Term
| THe impulse pathway of the heart |
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Definition
Sinoatrial (SA) Node
Atrial Cardiac Muscle
Internodal Fibers
Atrioventricular (AV) Node
AV Bundle (of His)
Right and Left Bundle Branches
Purkinje Fibers
Ventricular Cardiac Muscle |
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Term
| Which node has the fastest intrinsic rhythm of 100-110 bpm but is toned down by the vagus nerve to 60-100 bpm |
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Definition
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Term
| a faster than normal heart rate |
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Definition
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Term
| a slower than normal heart rate |
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Definition
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Term
| What is the target for the sympathetic nerve is cardiac tissue? |
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Definition
| SA, AV, and the ventricles |
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Term
| What is the target of the parasympathetic nerve for cardiac tissue |
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Definition
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Term
| How is blood deleivered to the heart? |
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Definition
| Coronary arteries and capillaries |
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Term
Blockages (or vascular spasms) in
Coronary Vessels that robs myocardium of O2 supply, disrupt contractile function and lead to cell death. |
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Definition
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Term
| A drug that breaks up a blood clot during a heart attack. |
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Definition
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Term
| SInce cardiac muscles are terminally differentiated and cannot divide to replace dead cells what develops? |
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Definition
| fibroblasts invade the site and form scars |
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Term
| What does hypoxia cause in cardiac muscle? |
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Definition
damage mitchondria
causes a cytochrome C release that initiates apoptosis this is further during reperfusion when there is a calcium influx from SR and mitochondria |
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Term
| What yields O2 radicals that further damage membranes |
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Definition
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Term
| What causes depolaarization in the ventricle and atria of the heart? |
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Definition
| the opening of fast voltage gated sodium channels |
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Term
| in ventricular and artial AP at the peak and the beginning of repolarization is due to |
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Definition
| the closing of sodium channels and the opening of potassium channels |
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Term
| Phase 2 the plateau in atral and ventricle AP is due to |
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Definition
the opening of slow voltage gated Ca channels and the release of Ca from the SR increase the Ca concentration in the cell.
Voltage gated K channels close but ungated K channels still open.
Allows for a gradual decay of AP so another one cannot occur |
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Term
| Calcuim channels close and voltage gated K channels reopen |
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Definition
| Occurs in Phase 3 of ventrical atrial AP |
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Term
| The type of Ca channel that opens during phase 2 of an atrial ventricle AP |
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Definition
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Term
| What is the stable resting membrane of phase 4 of an atrial ventricle AP due to |
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Definition
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Term
| Phase O of an SA node AP is due to |
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Definition
| slow voltage gate T- type channels opening allowing calcium to enter |
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Term
| Phase 3 of SA node AP repolarization is due to |
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Definition
| Voltage gated K channels opening |
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Term
| Phase 4 of the SA node depolarization is due to |
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Definition
"SPecific Na chnnels opening-->inward Na current-->increase excitability-->AP occurs when threhold is reached
Also could be a decrease of K conductance |
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Term
| WHich phase of the SA node AP sets the heart rate |
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Definition
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Term
| In cardiac AP what causes the release of Ca from the SR |
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Definition
| Calcium coming through L type voltage channels. Ca induced Ca release |
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Term
| The length of muscle fibers at the end of diastole just before contraction, what happens when the heart fills with blood |
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Definition
| Resting length and left ventricular end diastolic volume |
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Term
| THe greater the end-diastolic volume (preload), the greater the ventricular pressure that can be developed |
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Definition
| Starlings Law of the Heart |
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Term
| The process of filling the heart, the volume and pressure are increasing, the bottom curve |
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Definition
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Term
| as the ventricle contracts increase pressure the volume decrease, the top curve |
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Definition
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Term
| What make the contraction stronger in the heart |
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Definition
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Term
| How do you change the strength of contraction? |
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Definition
1. Change end-diastolic volume
2. Change cytosolic [Ca+2] = cardiac contractility |
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Term
: intrinsic ability of myocardial cells to develop
force at a given muscle length - correlates directly with [Ca+2]int |
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Definition
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Term
| Ways of changing contractility without changing preload (volume of blood) |
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Definition
Neurohumoral factors i.e. NE increases sarcolemma permeability to Ca+2
Increasing the frequency of contraction = treppe (tetany???? |
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Term
| a chemical that stimulates the sympathetic nervous system. a cardiac glycoside |
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Definition
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Term
| Why can't cardiac muscle experience tetany? |
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Definition
| the long refractory period |
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Term
| How does stimulation of the heart occur |
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Definition
| from the bottom of the heart upward |
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Term
| Contractility is correlated with |
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Definition
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Term
| the only muscle that has tone |
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Definition
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