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Cardiac & Smooth Muscle - P&P
8/21/08 Lectures
14
Medical
Professional
08/21/2008

Additional Medical Flashcards

 


 

Cards

Term
Describe the tissue features of cardiac muscle.
Definition
  • Branched fibers (makes irregular branching)
  • Central nuclei
  • Cross-striations
  • Intercalated disks
  • Intercellular spaces (accomodate abundant capillaries)
Term

Give descriptions for differentiating between the cell (fiber) types of cardiac muscle:

 

Atrial Cardiac Muscle

 

Ventricular Cardiac Muscle

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

Term

What are Purkinje fibers?

Where are they located?

What system are they associated with in cardiac muscle?

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

Term

What are some special features of cardiac cell strucure?

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

Term
What filaments anchor the fascia adherins?  Macula adherens?
Definition

Fascia adherens is a patch-like junction anchored with actin filaments

 

Macula adherens is a spot-like junction, anchored with desmin intermediate filaments

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

 

 

Definition

T-tubules are located at Z-lines in cardiac

 

Terminal cisternae are small

 

There are dyads

 

The sarcoplasmic reticulum is less extensive

Term
Where do cardiomyocytes form during embryonic development?
Definition
Mesoderm anterior to embryo's cranial region in the forming neural tube aggregate to form angiogenic cell clusters and differentiating cardiomyoblasts.
Term
What cardiac cell has to diverge from the development path followed for contractile tissues?
Definition
Purkinje cells
Term
List, in order, the steps of the impulse pathway followed by the conducting system of the heart.
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

Term
What is the rate of the normal "sinus rhythm"?
Definition

60-100/min

 

Sinus rhythm:  heart rate

 

Tachycardia:  too fast of a HR

 

Bradycardia:  too slow of a HR

Term

What happens in the Sympathetic System in regards to autonomic modulaion and innervation in cardiac muscle?

Definition
  • Speed up
  • Preganglionic:  Lateral cell column (thoracic area)
  • Postganglionic:  Sympathetic chain
  • Target:  SA & AV Node, Atrial & Ventricular Cardiac Muscle
Term

What happens in the parasympathetic System in regards to autonomic modulaion and innervation in cardiac muscle?

Definition
  • slow down
  • preganglionic:  medullary nuclei (brainstem)
  • Vagus nerve
  • postganglionic:  cardiac ganglia
  • targe:  SA & AV node, atrial muscle
Term
What allows you to not lose all contraction of the heart in the event that the SA node's function is lost?
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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