Cardiovascular Overview And Myocardial Function Flashcards
(40 cards)
Heart wall and covering
Fibrous Pericardium
Serous Pericardium
Function of pericardium
Protective function
Serous Pericardium
Parietal Pericardium
Visceral Pericardium
Heart Wall
Epicardium
Myocardium
Endocardium
Epicardium
Visceral Pericardium
Coronary vessels are housed
Provides the heart with blood
Function: lubricative outer covering
Myocardium
Muscles, reactive hyperemia
Function: provides muscular contractions that eject blood from heart chambers
Endocardium
In contact with blood inside the chambers, is continuous with endothelium
Function: Serves as protective inner lining of chambers and valves
4 Chambers
2 Atria
2 Ventricles
4 Valves
2 AV (bicuspid and tricuspid) 2 Semilunar (aortic and pulm)
Trace a drop of blood through CV System
do it :)
What is the importance of heart valves
When papillary muscles are contracted, valves close
Prevent backflow
The CV system is a ____ system
Closed loop
- Systemic - blood to tissues
- Pulmonary - blood to lungs
Pressure arterial vs. venous side
High pressure on arterial side
Low pressure on venous side
Which ventricle is normally thicker
Left ventricle
Has more pressure than the right, so thicker walls
Cardiac Output
ALL of it goes to the lungs 20% kidneys 24% liver and GI 21% skeletal muscle 4% coronary circulation 18% skin and other organs
Systemic organs are arranged in ___ Why?
Parallel
With parallel arrangement the total resistance is lower than each of the individual resistances
It is a method for keeping low resistance
Arrangement of Vascular Beds
Greater flow achieved with small changes in pressure
Greater ability to control flow to individual organs
Movement of blood flow depends on….
A pressure gradient
Gradient is established by contracting of AV valves
Our heart is generating contractile force that creates pressure
Myocardium similarities to skeletal muscle
- Striations
- Contracts according to sliding filament theory
- Alters force by cross bridge overlap
Myocardium differences from skeletal muscle
- No fiber types - all are ST like (high endurance, lot of mitochondria)
- Underdeveloped SR - relies heavily on extracellular calcium
- Gradates force by increasing Ca
- Intercalated Disks (allows functional syncytium - contract as one unit and allows free passage of ions through gap junctions)
- Single nuclei serving a single cell
- No satellite cells (no regeneration capacity)
Calcium Induced Calcium Release (CICR)
Small inc in Ca near the SR leads to a much larger Ca release from the SR
Required for contraction
What happens with the Ca
- Depolarization wave at the sarcolemma activates the VGCCs (DHPR)
- Ca influx activates Ca release channels on the SR (RYR)
- Increase in intracellular Ca
- Ca binds to troponin to activate the contractile element
Influx
VGCC (L type Ca channels)
NCX
Efflux
SERCA (80%) - Ca sequestered back into SR
NCX (20%)
