Hito Heart Flashcards
What are the components of the cardiovascular system?
The cardiovascular system includes the heart and blood vessels (arteries, veins, and capillaries).
What are the layers of the heart wall?
The heart wall consists of three layers: the endocardium (inner layer), myocardium (middle layer), and pericardium (outer layer).
What are the two main layers of the pericardium?
The pericardium has two main layers: the fibrous pericardium (outer layer) and the serous pericardium, which is divided into the parietal layer and the visceral layer (epicardium).
What is the composition of the endocardium?
The endocardium is composed of an endothelial layer, a subendothelial layer of loose connective tissue, a middle layer of denser connective tissue, and a subendocardial layer.
What are the characteristics of cardiomyocytes in the myocardium?
Cardiomyocytes are cylindrical, striated, contain one or two centrally located nuclei, and are connected by intercalated discs.
What is the structure of heart valves?
Heart valves are outgrowths from the endocardium, composed of dense fibrous connective tissue covered by endothelium, preventing the backflow of blood.
What are the features of cardiac muscle fibers?
Cardiac muscle fibers are striated, involuntary, have one or two centrally located nuclei, and are interconnected by intercalated discs.
Describe the sarcoplasmic reticulum and T tubules in cardiac muscle cells.
The sarcoplasmic reticulum is less organized, and T tubules are wider and occur at the Z line, forming a diad with the sarcoplasmic reticulum, essential for excitation-contraction coupling.
What is the function of intercalated discs?
Intercalated discs connect cardiac muscle cells, providing mechanical strength and electrical continuity for synchronized contraction.
Name a special feature of the heart related to its muscle type.
The heart is made of cardiac muscle, which combines properties of both skeletal and smooth muscle, contracting involuntarily and rhythmically without fatigue.
How does cardiac muscle repair after injury?
Cardiac muscle cells are replaced by fibrous connective tissue, leading to loss of function at the injury site.
What is the composition of the fibrous pericardium?
The fibrous pericardium is composed of dense irregular connective tissue, rich in collagen fibers, providing strength and protection.
What is the function of the serous fluid between the parietal and visceral layers of the serous pericardium?
The serous fluid allows for smooth movement of the heart within the pericardial sac, reducing friction during heartbeats.
What is the role of the endothelium in the endocardium?
The endothelium provides a smooth, non-thrombogenic surface for blood flow within the heart chambers.
What is found in the subendocardial layer of the endocardium?
The subendocardial layer contains loose connective tissue, blood vessels, nerves, and Purkinje fibers.
What is the function of the sarcoplasmic reticulum in cardiac muscle cells?
The sarcoplasmic reticulum plays a crucial role in calcium regulation during muscle contraction and relaxation.
Why is the myocardium rich in capillary blood vessels?
The myocardium requires a rich supply of oxygen and nutrients to sustain its continuous contractile activity, which is facilitated by its extensive capillary network.
What is the role of Purkinje fibers found in the subendocardial layer?
are specialized cardiac conduction cells that facilitate the rapid propagation of electrical impulses, ensuring coordinated contraction of the ventricles.
How does the thickness of the myocardium vary between different heart chambers?
The left ventricle has the thickest muscular wall, followed by the right ventricle, and then the atria, to accommodate different pressures required for pumping blood.
What is a key feature of the myocardium’s regeneration capacity?
The myocardium has very limited regenerative capacity, and most cardiac muscle cells do not divide after birth.
Describe the structure and organization of the myocardium?
The myocardium forms the main part of the cardiac wall, consisting of a network of cardiac muscle fibers that spiral in layers around the heart. It also contains a rich capillary network in between the muscle fibers.
Define the key components of a cardiac muscle fiber?
- Muscle cell. Also known as the muscle fiber.
- Sarcolemma. The plasma membrane of the muscle fiber.
- Sarcoplasm. The cytoplasm of the muscle fiber.
- Sarcoplasmic reticulum. The smooth endoplasmic reticulum (sER) in muscle fibers.
- Sarcosome. The mitochondria in muscle fibers.
