The Heart Flashcards
What makes up the looser connective tissue layer of the endocardium?
Fibroelastic connective tissue
What types of tissues and fibers make up the dense irregular connective tissue layer of the endocardium?
More collagen I and elastic fibers and some smooth muscles (for support not contraction)
What is a term used to describe the looser connective tissue layer and dense irregular layers of the endocardium?
Sub-endothelium connective tissue layer
What makes up the sub-endocardial layer of the endocardium?
Looser connective tissue with blood vessels, nerves
Where are the Purkinje fibers located in the endocardium?
Within the sub-endocardium
What are Purkinje fibers?
Modified cardiac myocytes
What substance is stored in the Purkinje fibers?
Glycogen
How are Purkinje fibers attached?
Gap junctions and desmosomes
What is the function of the Purkinje fibers?
To conduct contraction impulse rapidly
What chambers of the heart have less muscle and more elastic fibers?
Atria
What chambers of the heart have well-developed cardiac muscle layer?
Ventricles
What portion of the intercalated discs are the risers of the stairs?
Transverse
What portion of the intercalated discs are the steps of the stairs?
Longitudinal portion
What cell junctions make up the transverse portion of the intercalated discs?
Macula adherens and fascia adherens
What portion of the intercalated discs have large gap junctions which enable the flow of ions for contraction?
Longitudinal portion
What is the function of the macula adherens in the transverse portion of the intercalated discs?
Attach cardiomyocytes in a row
What is the function of fascia adherens in the transverse portion of the intercalated discs?
Attach and stabilize myofibrils
What are the three functions of the intercalated discs?
Arrange cardiac myocytes in a row, attach and stabilize myofibrils, cell to cell communication/transfer of ions
What is the effect of the sympathetic nervous system on heart rate and contraction force?
Increased
What is the effect of the parasympathetic nervous system on heartbeat and contraction strength?
Slowed and decreased
What are the specialized cardiac cells that have an endocrine function in the atria and interventricular septum?
Myoendocrine cells
What are the endocrine functions of the myoendocrine cells and what organs or structures do they target?
Fluid and electrolyte balance (target the kidneys)
Decrease blood pressure (target the small arteries and arterioles)
What is another name for the epicardium?
Visceral pericardium
What is another name for the pericardium?
Serous pericardium
What makes up the sub-epicardial fibroelastic connective tissue layer of the visceral pericardium?
Coronary vessels, nerves, sometimes adipose
What part of the epicardium secretes a serious lubricating fluid?
Mesothelium
What are the two parts of the parietal pericardium?
Mesothelium and a layer of fibroelastic connective tissue
What type of cells make up the endothelium of the endocardium of the heart?
Simple squamous cells
What layers make up the pericardial sac?
Parietal pericardium and fibrous pericardium
What is the volume of the pericardial cavity?
About 15-50 milliliters
The pericardial cavity is located in between what layers?
Parietal pericardium and visceral pericardium
What is the general valve histology of the heart?
Endothelium with dense irregular tissue below made of collagen I and elastic fibers (almost avascular)
What type of connective tissue primarily makes up the cardiac skeleton?
Dense irregular connective tissue
What are the three main components of the cardiac skeleton?
Annuli fibrosi, trigonum fibrosum, septum membranaceum
Where is the annuli fibrosi located in the cardiac skeleton?
Around the base of the aorta, pulmonary arteries, and openings to the chambers
Where can the trigonum fibrosum of the cardiac skeleton be found?
By cusps of aortic valve
Where can the septum membranaceum of the cardiac skeleton be found?
Upper portion of interventricular septum
What is the function of the septum membranaceum?
Origin and insertion of cardiac myocytes
What type of connective tissue is associated with chordae tendinae?
Dense regular connective tissue (because it’s tendon-like)
What is the overall function of the cardiac skeleton?
Isolates atrial and ventricular myocardia to ensure individual chamber contractions
What is angina?
Chest pain usually brought on by exertion
What is the cause of angina?
Slow progressive narrowing of the coronary vessels (therefore less oxygen)
What is dysrhythmia of the heart?
Abnormal heart rhythms
What is the cause of dysrhythmia?
Damage or death occurs to Purkinje fibers and other conducting tissues
What is pericarditis?
Inflammation of the pericardial cavity and therefore inflammation of the serous pericardium
