Term
| Acetylcholinesterase does what? |
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Definition
| inactivates a neurotransmitter (acetylcholine) |
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Term
| The neuromuscular junction |
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Definition
= motor end plate
-is the junction b/t a motor neuron and a skeletal muscle fiber
-transmits an action potential b/t the nerve cell and muscle cell on a one to one basis (but does not initiate action potential_ |
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Term
| Which type of receptor binds norepinephrine on cardiac muscle, thus increasing cardiac activity? |
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Definition
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Term
| What chemical paralyzes skeletal muscle by binding to the acetylcholine receptor sites? |
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Definition
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Term
| t/f: the neurmuscular unction is always excitatory? |
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Definition
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Term
| t/f: the autonomic nervous system controls the motor activity of skeletal muscles |
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Definition
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Term
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Definition
| Recieves blood from the left ventricle and is a high pressure system compared to the pulmonary circulation |
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Term
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Definition
| prevent backflow of blood from the arterial trunks to the ventricles |
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Term
| The primary function of thepericardial sac is to |
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Definition
| secrete a fluid that reduces friction as the heart beats |
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Term
| The heart chamber having the greatest work load is the |
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Definition
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Term
| What vessel that carries blood with a comparatively high concentration of oxygen |
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Definition
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Term
| The aortic valve does what |
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Definition
| prevents the backflow of blood into the left ventricle during ventricular diastole |
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Term
| what is the proper sequence of blood flow through the circulatory system? |
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Definition
| venae cavae --> right atrium --> right ventricle -->pulmonary artery --> lungs --> pulmonary vein --> left atrium --> left ventricle --> aorta --> systemic tissues |
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Term
| The low-resistance pathway that permits electical activity pass from cell-to-cell in mycardial tissue is the : |
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Definition
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Term
| The plateau of the cardiac action potential results from teh opening of voltage-gated slow _____ chanels in the plasma membrane of hte cardiac cell |
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Definition
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Term
| On a normal ECG, a wave for repolarization of the atria is not recorded. Why? |
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Definition
| It occurs simulataneously with ventricular depolarization and is masked by the QRS complex |
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Term
| The AV nodal delay is for what purpose? |
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Definition
| It ensures that the atra contract and empty their contents into the ventricles prior to ventricular systole |
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Term
| The normal pacemaker of the heart is the |
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Definition
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Term
| The direction of the impulse through the conduction system of the heart for each cardiac cycle is normally |
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Definition
| SA node --> AV node --> Purkinje fibers --> SA node |
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Term
| The QRS complex represents: |
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Definition
| depolarization of the ventricles |
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Term
| Which of the following ECG waves represents ventricular repolarization? |
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Definition
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Term
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Definition
| uncoordinate excitation and contraction of cardiac cells |
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Term
| Why can't tetany of the heart occur? |
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Definition
| The refractory period in cardiac muscle lasts almost as long as the duration of the resultant contraction |
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Term
| The volume of blood ejected from each ventricle during a contraction is called the? |
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Definition
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Term
| All of the following negatively influence the myocardium's contractility, thus increasing ESV except |
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Definition
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Term
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Definition
| signals the onset of ventricular systole |
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Term
| The end systolic volume is |
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Definition
| the volume of blood in the ventricle when ejection is complete |
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Term
| according to the frank-starling law of the heart |
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Definition
| increasing the venous return increases the end diastolic volume, which leads to an increased stroke volume, so the heart normally pumps out all the blood returned to it |
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Term
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Definition
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Term
| what is the cranial nerve of hte parasympathetic nervous system that signals the heart |
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Definition
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Term
| The ____ nerves to the heart alter cardiac output by incrasing heart rate and incrasing contractility |
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Definition
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Term
| which of hte following organs recieves the most blood flow? (heart, kidney, brain, muscle, liver) |
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Definition
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Term
| Resistance increases when |
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Definition
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Term
| Blood flow is affected by |
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Definition
-pressure differences
-the viscosity of the blood
-The amount of the friction in the blood vessels
-the length and diameter of the blood vessels |
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Term
| What is true about blood pressure? |
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Definition
-its maximal during ventricular systole
-it decreases the fartehr away from the heart
-it increases with increasing resistance
-it decreases with incrasing vessel diameter |
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Term
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Definition
| occurs when tehre is a decrease in teh radius of a vessel |
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Term
| Becasue the arteries have large radii, they serve as exellent rapid-transit passageways for blood. Their second function, related to their elasticity, is to act as a ______ for maintaining blood flow during diastole |
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Definition
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Term
| What is the term for the peak pressure exereted by ejectiong blood against vessel walls during cardiac contraction |
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Definition
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Term
| The pulse pressure is the |
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Definition
| difference between the systolic and diastolic |
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Term
| mean arterial pressure is |
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Definition
| diastolic pressure (pulse pressure/3) |
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Term
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Definition
their walls contain a thick layer of smooth muscle
-ther are responsible for the distribution of blood flow to the various organs
-they are the major vessels that contribute to total peripheral reistance
they are richly innervated by sympathetic nerve fibers |
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Term
| Increased respiration within a tissue leads to vasodilation of arterioles b/c: |
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Definition
-carbon dioxide levels increase
=oxygen levels decrease |
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Term
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Definition
-serves as endothelial-derived relaxing factor
-NO is the direct mediator of penile erection
-is released as "chemical warfare" by macrophages of the immune system
-NO serves as a novel type of neurotransmitter in the brain |
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Term
| Most sympathetic fibers release ______ at the arterioles |
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Definition
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Term
| The major resistance vessels of hte body are the |
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Definition
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Term
| During exercies, there is not an increased blood flow to what tissue? |
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Definition
| The brain ( because blood flow to the brain is always constant) |
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Term
| What force continues to drive blood through the vasculature during ventricular diastole? |
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Definition
| -THe elastic recoil of the stretched arterial walls provides the force to continue blood flow in the remaining vascular system during ventricular diastole |
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Term
| t/f: increasing end-systolic volume increases stroke volume |
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Definition
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Term
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Definition
| receives most of its blood supply during ventricular diastole by means of the coronary circulation |
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