9: Cardiac Histo And Lymphatics Flashcards
Where are lymphatic capillaries?
Found among capillary beds
Two characteristics of lymphatic capillaries
- 1 way valves for collecting lymph
2. Incomplete basal lamina and openings between endothelial cells -> increased permeability
What are initial lymphatic vessels called after lymphatic capillaries?
Collecting lymphatic vessels
Walls of lymphatic vessels
Contain vascular tunics and valves; increase in thickness as vessels increase in size
What do the right lymphatic duct and thoracic duct drain?
R lymphatic: R side of head, neck, RUE, and R thorax
Thoracic duct: everything else
Where do R lymphatic duct and thoracic duct dump into?
R lymphatic duct: junction of R subclavian + RIJ
Thoracic duct: junction of L subclavian + LIJ
Outermost layer of heart wall
Epicardium
Thickest layer of the heart
Myocardium
3 functions of intercalated discs
Binds cells, transmits force of contraction, allows spread of excitation
Where are diad T-tubule systems found?
Z lines
What does the T tubule system permit?
Uniform contraction of myofibrils within a single cardiocyte
What are Purkinje fibers higher in compared to cardiocytes?
Glycogen
T tubules in Purkinje fibers
Mostly lacking
Cardiac skeleton histo
Dense irregular CT
Where is cardiac skeleton found in heart?
Endocardium; in interventricular and interatrial septa
Two big functions of cardiac skeleton
- Anchors valves for chordae tendinae insertion
2. Electrical insulator between atria and ventricles
Heart valve histo
Core of fibroelastic CT covered by endothelium
What are heart valves continuous with?
Cardiac skeleton
Valve ring
Part of heart valve formed by condensed fibroelastic layer of endocardium - creates the central portion of the valve
