Lecture 3: Anatomy of the Heart II Flashcards
What is the function of Atrioventricular AV valves?
Does the right and left side of the heart have AV valves?
- Prevent blood from returning to the atria during ventricular contraction
Right = tricuspid valve Left = bicuspid valve
What are Semilunar SV valves?
What are examples of SL valves?
SL valves are pushed open as blood flows out of the heart and close as back flow starts.
Aortic valve = three cusps
Pulmonary valve = three cusps
What happens to the heart valves during diastole - passively filling phase ?
- fluid is moving from the atria to the ventricles
- AV valves are open, SL valves are closed
What happens to the heart valves during systole ?
- pressure in the ventricles has reached a point where blood is ejected from the ventricles through the SL valves
- SV valves are open and AV valves are closed
What is the position of the left coronary artery?
It runs over that anterior wall of the heart and in the interventricular septum
- this branches off to form the circumflex artery
What does the right coronary artery do?
Supplies most of the blood to the posterior aspect of the heart via the posterior inter ventricular artery
Purkinje cells are communicating cells which coordinate contractions of the heart what is there structure?
- central nucleus
- mitochondrial and lots go glycogen
- Lots of gap junctions
- Little intercalated disks, demosomes & adhesion belts
What is the structure of cardiac muscle?
- striated
- short branching cells
- mononucleate
- central oval nucleus
- Interconnected with neighbouring cells via intercalated disks
- Mitochondria make up 25% or cell volume
- Irregular branched sacromeres
Intercalated disks connect cardiac muscle cells together, what are the 3 junction types?
- Adhesion belts
- Desmosomes
- Gap junctions
What do adhesion belts do?
Links actin with actin
- allows physical propagation of contraction from one cell to its neighbour by physically pulling on contractile units.
What do desmosomes do?
Links cytokeratin with cytokeratin
- Holds the cells in sheets - knits them together
What do gap junction do?
Allow electrochemical communication
- found along horizontal portion and allows for continuous contraction and rapid communication
