Term
| Describe the tissue features of cardiac muscle. |
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Definition
- Branched fibers (makes irregular branching)
- Central nuclei
- Cross-striations
- Intercalated disks
- Intercellular spaces (accomodate abundant capillaries)
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Term
Give descriptions for differentiating between the cell (fiber) types of cardiac muscle: Atrial Cardiac Muscle Ventricular Cardiac Muscle |
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Definition
Atrial Cardiac Muscle: -Smaller cells -Fewer T-tubules -Small dense granules contianing atrial natriuretic peptide Ventricular cardiac muscle: -larger cells -more T-tubules -no granules |
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Term
What are Purkinje fibers? Where are they located? What system are they associated with in cardiac muscle? |
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Definition
Purkinje fibers are modified cardiac muscle fibers They are sparse, peripherally located myofilaments, between the ventricular endocardium and contractile muscle They are part of the conducting system of the heart |
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Term
What are some special features of cardiac cell strucure? |
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Definition
Special feaures of cardiac cell structure include: -Irregular myofibrils (due to branching) -Myofibril bands being out of register (with striations difficult to see) -Abundant mitochondria -Organelles collect at nuclear poles -Intercalated disks join cells end-to-end |
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Term
| What filaments anchor the fascia adherins? Macula adherens? |
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Definition
Fascia adherens is a patch-like junction anchored with actin filaments Macula adherens is a spot-like junction, anchored with desmin intermediate filaments |
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Term
In the cardiac membrane system where are T-Tubules located? What is the size of the terminal cisternae? Is it a dyad or triad? What is the extent of the sarcoplasmic reticulum |
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Definition
T-tubules are located at Z-lines in cardiac Terminal cisternae are small There are dyads The sarcoplasmic reticulum is less extensive |
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Term
| Where do cardiomyocytes form during embryonic development? |
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Definition
| Mesoderm anterior to embryo's cranial region in the forming neural tube aggregate to form angiogenic cell clusters and differentiating cardiomyoblasts. |
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Term
| What cardiac cell has to diverge from the development path followed for contractile tissues? |
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Definition
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Term
| List, in order, the steps of the impulse pathway followed by the conducting system 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
| What is the rate of the normal "sinus rhythm"? |
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Definition
60-100/min Sinus rhythm: heart rate Tachycardia: too fast of a HR Bradycardia: too slow of a HR |
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Term
What happens in the Sympathetic System in regards to autonomic modulaion and innervation in cardiac muscle? |
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Definition
- Speed up
- Preganglionic: Lateral cell column (thoracic area)
- Postganglionic: Sympathetic chain
- Target: SA & AV Node, Atrial & Ventricular Cardiac Muscle
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Term
What happens in the parasympathetic System in regards to autonomic modulaion and innervation in cardiac muscle? |
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Definition
- slow down
- preganglionic: medullary nuclei (brainstem)
- Vagus nerve
- postganglionic: cardiac ganglia
- targe: SA & AV node, atrial muscle
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Term
| What allows you to not lose all contraction of the heart in the event that the SA node's function is lost? |
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Definition
| Innervation of the cardiac muscles and AV node allow the heart to continue beating with loss of the SA node, even though it will beat slower. |
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