Test 3 Study Guide Part 1 Flashcards
Which muscles are striated?
What does this mean?
Cardiac, Skeletal
Means that they have sarcomeres. It also means that smooth muscles do not.
What are intercalated disks:
They are the connexin proteins in gap junctions
Myocardium:
- Define:
- Define:
A myocardium is a collection of muscle cells which are all interconnected by gap junctions
What are the implications of the interconnection of myocardium by gap junctions?
What two myocardiums exist in the heart?
They will contract as a single unit with small levels of delay. They will also not very significantly contractile strength, as all muscle cells are contracting at once (unlike the skeletal muscle)
Atria and the ventricles (non conductive tissue separates them)
While all cells of a myocardium must contract, what factors can effect the strength of their contraction?
Epinephrine (fight flight) and stretching of the heart chambers (perhaps a counter mechanism for bursting or damage from hyper tension?)
The heart is said to have intrinsic rhythmicity. What causes this?
The regular firing of the sinoatrial node (SA node) which then activates the AV node (atrioventricular node)
Ca2+ intake into the heart works how?
The heart used DHP (dihydropyridine receptors) to allow Ca2+ to bind to RyR2 and activate it, allowing influx of Ca2+ from the SR
The heart still has t-tubules
This is true.
How is Ca2+ returned into the SR?
By serca pumps (sarcoplasmic/endoplasmic reticulum calcium ATPase)
Where are only circular smooth muscles found?
Where are circular and longitudinal smooth muscles found?
In the branchoiles and blood vessels (where only regulation of diameter is necessary)
The digestive tract, ductus deferens, ureter, and fallopean tubes (necessary to have longitudinal and circular for peristalsis
Smooth muscles do not have sarcomeres but does have actin an myosin. How is it arranged?
A smooth muscle will have dense bodies (large proteins) which act to anchor the actin filaments. The actin filaments will also be longer. The filaments will be laid out and cross over each other without the clear directionality. This means that smooth muscle when contracted will try to shrink.
Myosin cross bridges are more perpendicular to myosin thick filaments in smooth muscle cells
True
What structural elements allow smooth muscles to contract when stretched?
How stretched can they be and contract?
Their dense body arrangement means they can be stretched any direction. Longer thin and thick filaments also help.
8x in the stomach.
Most of your Co2 travels in your plasma:
Implication:
This is why blood co2 levels are detected and not O2 levels (which travel in RBCs)
Circulatory system differentiation:
- Cardiovascular system (only heart and blood vessels)
- Lymphatic system (one way)
- Circulatory system (can be considered to be the lymphatic and cardiovascular but most people consider it only cardiovascular)
The heart pumps how much blood per minute?
How long does it take a RBC to move from the heart, to the most distal portion of the vascular system and back?
Where does the heart maintain pressure?
5 liters
1 minute
The arterioles
Capacity of the cardiovascular system:
about 5 liters
Difference in color between oxygenated and non-oxygenated blood:
oxygenated:
- bright red
non-oxygenated blood:
- a maroon
What percent is human blood is plasma?
What percent is WBCs?
What percent is RBCs?
55%
much less than 1%
45%
What is the hematocrit?
The level of RBCs. If 40% of your blood is RBCs then your hematocrit is 40% and your plasma levels are 60%.