Shared Flashcard Set

Details

Cardiovascular System Histology
N/A
52
Histology
01/04/2012

Additional Histology Flashcards

 


 

Cards

Term
Endothelium is a lining of what types of cells?
Definition
Simple squamous epithelium
Term
The cardiovascular system is lined by what?
Definition
endothelium
Term
What are the three layers/tunics of the heart?
Definition
Endocardium, myocardium, epicardium
Term
Endocardium is continuous with what?
Definition
Tunica intima of vessels entering the heart
Term
Myocardium is composed of what?
Definition
Cardiac muscle
Term
How is myocardial cardiac muscle arranged?
Definition
Layered, spiral pattern
Term
What is the name of the simple squamous epithelium covering the epicardium?
Definition
Mesothelium?
Term
What is the outer tunic of the heart wall?
Definition
Epicardium
Term
What cells are responsible for the contractility of the myocardium?
Definition
Myocytes (cardiac muscle cells)
Term
A centrally-located nucleus, lipofuschin granules near the nucleus, and poorly developed t tubles describes what cells?
Definition
Cardiac myocytes
Term
Mitochondria in ventricular myocytes are found where?
Definition
Adjacent to the sarcolemma between myofibrils
Term
How do t tubles of cardiac muscle cells compare to those of skeletal muscle?
Definition
Much larger in diameter, less extensive
Term
SR terminal cisterna and an apposed t tubule associate to form what?
Definition
Diads
Term
Cardiac muscle diads occur where?
Definition
Z-disc
Term
Junctional complexes at the ends of cardiac myocytes used for cell to cell attachment and ionic coupling are known as what?
Definition
Intercalated discs
Term
Intercalated discs are one of the most distinctive histological features of cardiac myocytes and sometimes appear as what?
Definition
Stairstep pattern
Term
Intercalated discs possess what important specializations?
Definition
Fascia adherens, desmosomes, gap junctions
Term
What is the attachment site for actin filaments of terminal sarcomeres of cardiac myocytes?
Definition
Fascia adherens
Term
What is located in the transverse portion of a cardiac myocyte Z-disc?
Definition
Fascia adherens, desmosomes
Term
What is located on lateral portions of a cardiac myocyte Z-disc?
Definition
Gap junctions
Term
What is responsible for physically holding myocyte ends together?
Definition
Desmosomes
Term
What protein hexamer forms gap junctions between cardiac myocytes?
Definition
Connexons
Term
What is largely responsible for the wave of contraction that spreads throughout the heart wall?
Definition
Gap junctions
Term
Depolarization of a cardyac myocyte sarcolemma is carried to the next myocyte via ion flow through what?
Definition
Connexons/Gap junctions
Term
Ay any given depth, all myocytes of that layer run in what direction?
Definition
Parallel
Term
Multiple layers of cardiac myocytes insert into what?
Definition
Fibrous skeleton of the heart
Term
The twisting and lifting motion of ventricular contraction is a functional result of what?
Definition
Myocyte layering pattern
Term
How are myocyte layers oriented?
Definition
Angled to adjacent layers
Term
What are the different segments of the fibrous skeleton of the heart?
Definition
Annuli fibrosi, trigonum fibrosum, septum membranaceum
Term
What portion of the fibrous skeleton of the heart is found surounding the bases of the aorta, pulmonary artery, and atrioventricular orifices?
Definition
Annuli fibrosi
Term
What segment of the fibrous skeleton of the heart is found near the aortic valve cusp?
Definition
Trigonum fibrosum
Term
What segment of the fibrous skeleton of the heart is found in the upper portion of the atrioventricular septum?
Definition
Septum membranaceum
Term
What structural discontinuity between atrial and ventricular muscles ensures that the contraction of atria and ventricles will not occur simultaneously?
Definition
Fibrous skeleton of the heart
Term
Cardiac valves attach to what?
Definition
Fibrous skeleton of the heart
Term
Where is the Sinoatrial (SA) node located?
Definition
Right atrium near junction iwth the superior vena cava
Term
What is the site of initiation of excitation, also referred to as the pacemaker of the heart?
Definition
SA node
Term
Both the SA node and purkinje fibers lack what common feature of cardiac myocytes?
Definition
Intercalated discs
Term
What is the average rate of spontaneous depolarization by the SA node?
Definition
70 beat per minute
Term
What is comprised of cells that carry impulses from the SA node to the AV node?
Definition
Internodal tract
Term
Where is the atrioventricular (AV) node located?
Definition
Lower right side of the interatrial septum
Term
What gives rise to left and right bundle branches that send conduction impulses into the unspecialized myocardium of the ventricles?
Definition
AV bundle (bundle of His)
Term
Which node conducts impulses relatively slowly, contributeing to the necessary delay between atrial and ventircular filling?
Definition
AV node
Term
What myocardial fibers are specialized for rapid impulse conduction?
Definition
Purkinje fibers
Term
What connects cells of Purkinje fibers?
Definition
Gap junctions
Term
True or false: Purkinje fibers are developmentally related to Purkinje cells of the cerebellum.
Definition
False
Term
Depolarization of the myocyte membrane opens what voltage gated channels?
Definition
Ca++ channels
Term
What induces Ca++ release from the SR of cardiac muscle?
Definition
Voltage gated Ca++ channels
Term
What accounts for most of the Ca++ that binds to TnC, initiating actin-myosin interaction?
Definition
Ca++-induced Ca++-release response triggered at diads
Term
What removes Ca++ from the sarcoplasm in cardiac muscle?
Definition
Ca++ pump proteins
Term
What removes Ca++ that has entered the cell during cardiac muscle excitation?
Definition
Na+/Ca++ exchanger protein
Term
Where is the Na+/Ca++ exchanger protein that pumps Ca++ out of cardiac muscle cells located?
Definition
Sarcolemma
Term
What is the ratio of exchange in Na+/Ca++ exchanger proteins?
Definition
One Ca++ out, three Na+ in