Dr. Musch Test 3 info Flashcards
Mean Arterial pressure is the product of what 2 variables?
MAP= Q x SVR
According to the Fick equation, oxygen uptake (VO2) is the product of what two varibales
Fick equation= VO2= Q x a-VO2
Cardiac output (Q) is the product of what two variables?
Q= HR x SV
The output of the right ventricle is equal to the output of the left ventricle. True or False?
True
How much of the total blood volume is found on the venous side of circulation?
70%
What are the major differences between the right and left ventricle in regards to structure and function?
A. right ventricle- volume pump- pumps to pulmonary circulation
B. Left ventricle - pressure pump- pumps to systemic circulation (thicker)
The electrical potential from one cardiac muscle cell is transferred to another cardiac muscle cell. What structure contributes to this transfer between cells?
intercalated disk
cardiac muscle cells can contract on their own without any nerve innervation. Can skeletal muscle cells do the same?
NO
What relationship contributes to intrinsic regulation of stroke volume and therefore cardiac output.
Q= HR x SV SV= the difference between end diastolic volume (EDV) and end systolic volume (ESV)
Explain the anatomical difference between the sympathetic and parasympathetic nerves
a. Sympathetic nerves- originate in spine between 1st thoracic (T1) and second lumbar (L2) vertebrae
b. parasympathetic nerves- originate in the cranial nerves
What influence does the sympathetic and parasympathetic nerves have on the heart?
a. sympathetic nerves (spinal cord)- NE stimulate B1 receptor in the heart, which increases HR
b. parasympathetic nerves- (cranial nerve, vagus)- ACh, which stimulates the muscarinic receptor in the heart which decreases HR
What is the neurotransmitter of the sympathetic nervous system?
Norepinephrine
What type of receptor does NE stimulate in the heart?
B1 receptors in the heart
What is the neurotransmitter of the parasympathetic nervous system?
ACh - acetylcholine
What type of receptor does ACh stimulate in the heart?
Muscarinic receptors
The ECG or EKG can be broken down into three different electrical events. what are they?
- P wave- atrial depolarization (contraction)
- QRS complex- atrial repolarization and ventricular depolarization
- T wave- ventricular depolarization
What is the primary factor that determines ventricular end- diastolic volume (LVEDV)?
Preload
- blood volume
- body position
- pumping action of the skeletal muscle
- atrial contribution to ventricular filling-exercise
- venous tone (venous return)
Baroreceptors are mechanoreceptors and sense changes in stretch due to changes in arterial pressure. True or false?
True
- increasing arterial bp they act to inhibit sympathetic centers, which reduces Q
- bp drops- less impulses sent to vasomotor center, which decreases the parasympathetic tone and increases sympathetic tone
Baroreceptors are located in 2 different places in the cardiovascular system. Name the 2 different places.
1) aortic arch
2) carotid arteries
What are the hearts mechanical events that follow the three different electrical events?
p wave (atrial depolarization) QRS complex ( atrial repol and ventricular depol) T wave (ventricular repol)
If there is very low pressure in the systemic circulation the baroreceptors sense this low pressure and activates the ________ nervous system.
sympathetic nervous system
The activation of the sympathetic nervous system results in increases in 3 different hemodynamic variables that work to bring pressure up back towards normal values. They are:
- HR - NE stimulates B1 receptors in the heart to increase HR
- SV- alpha receptors in venous return - frank starling cause vasoconstriction therefore increasing SV
- SVR- alpha receptors cause vasoconstriction in arterioles
What is the mean pressure in the capillaries?
30 mmHg
Left ventricular end- diastolic pressure is 5-7 mmHg in normal individuals, but the diastolic blood pressure in the brachial arteries is 80 mmHg. Why are theses diastolic pressures different?
pressure decreases due to aortic valve opening and closing, 2/3 time spent in diastole (relaxation)
The cross sectional area of the circulatory system is at its greatest in the capillaries. True or false?
True
The velocity of blood is at its greatest in the aorta and at its lowest in the vena cava. True or false?
the lowest velocity is in the capillaries
What type of blood vessel has the greatest wall to lumen ratio?
wall to lumen ratio is greatest in ARTERIOLES
what blood vessels are known as regulators?
arterioles
what is the diameter of a capillary?
6 microns
Left ventricular end diastolic pressure is 7-8 mmHg in normal individuals, but the diastolic blood pressure in the brachial arteries is 80 mmHg. What are these diastolic pressures different?
pressure decreases due to the aortic valve opening and closing
the cross-sectional area of the circulatory system is at its greatest in the capillaries. True or False?
TRUE. cross sectional area of the circulatory system is greatest in capillaries
The velocity of blood is at its greatest in the aorta and at its lowest in the vena cava. True or false?
False
Velocity of blood is greatest in aorta, and lowest in the capillaries