Muscles
Review
Review
These represent the three types of muscle tissue and the level of control we exert on each.
What are skeletal (voluntary), smooth (involuntary), and cardiac (involuntary)?
List the steps that occur when tropomyosin is bound to actin, and a cross-bridge needs to form.
What is calcium binding to troponin, causing the troponin-tropomyosin complex to shift away and expose the myosin binding site on actin?
Identify the two circulations of the heart, and the substance each delivers.
What are systemic circulation (oxygenated blood to body) and pulmonary circulation (deoxygenated blood to the lungs)?
Describe the plateau phase of the cardiac action potential, (place in the order, membrane potential, and the ions involved).
What is phase 2, a prolonged depolarized state maintained by increased Ca²⁺ entry through L-type VGCCs and decreased K⁺ permeability?
In the case that a patient's sinoatrial node fails, which structure takes over pacemaker functions, and will the heart rate be faster or slower than normal?
The AV node takes over with a slower rate.
A person experiences significant blood loss. What would happen to blood pressure, and what systems would compensate?
sympathetic nervous system would increase heart rate and stroke volume (raising CO)
α-adrenergic receptors cause vasoconstriction (raising TPR), both acting to restore MAP
List the three necessary proteins for forming a cross-bridge with myosin in the thick filament.
What are actin, troponin and tropomyosin?
A patient is prescribed an acetylcholinesterase inhibitor; they would experience this change in muscle contraction.
Muscles would remain contracted because ACh would not be broken down, so the signal to contract in the neuromuscular junction would be unable to deactivate.
List the valves and chambers of the heart, in the order that blood travels.
What is the right atrium, tricuspid valve, right ventricle, pulmonary semilunar valve, left atrium, bicuspid (mitral) valve, left ventricle, and aortic semilunar valve?
This is the state of the bicuspid and tricuspid valves during ventricular systole.
What is closed (while the aortic and pulmonary semilunar valves open)?
Explain the how cardiac muscle operates without experiencing tetanus.
What is the plateau phase of the cardiac AP extending the refractory period?
A patient's ECG shows an abnormally long PR interval, and it is found to be an issue with pacemaker cells. Identify the cell likely to cause this issue.
What is the AV node?
These are the two major substances needed to form cross-bridges during muscle contraction, and the structure that releases them.
What are ATP (mitochondria) and calcium ions (sarcoplasmic reticulum)?
Tell me why rigor mortis (stiffening after death) occurs, given what you know about the cross-bridge cycle.
Without ATP, myosin cannot detach from actin; the cross-bridge cycle is stuck, causing permanent stiffening.
This node is the primary pacemaker cell and its location.
What is the sinoatrial (SA) node, located in the right atrium?
This blood vessel possesses the thickest tunica media.
What is the artery?
Describe the capabilities of a patient with a low EF (ejection fraction).
What is poor contractile function because of an irregularly disproportionate ejected blood volume?
When venous return increases during exercise, this happens to stroke volume.
What is higher SV (Higher EDV -> Stretch ventricle more -> Higher SV)?
Name, draw, and label the functional unit of contraction within a myofibril.
What is the sarcomere?
Explain what muscle fiber type would be dominantly used by a sprinter as opposed to a marathon runner.
What is fast-glycolytic (Type IIx) fibers for speed (sprinter) What is slow-oxidative (Type I) fibers for fatigue resistance (marathon runner)?
The QRS complex represents these parts of the cardiac cycle on an ECG. A: Ventricular depolarization (and atrial repolarization)
What is ventricular depolarization (and atrial repolarization)?
Explain the parasympathetic nervous system's pathway of slowing heart rate.
What is ACh binds to muscarinic receptors, activating Gi, decreasing cAMP, causing slower opening voltage-gated K⁺ channels and funny channels?
During vigorous exercise, cardiac output rises from 5 L/min to 25 L/min. These two variables account for this increase.
Heart rate (HR) and stroke volume (SV)
because CO = HR × SV
What explains the continuation blood flow to tissues during ventricular diastole, when the heart is not actively pumping?
The aorta's elastic walls store energy during systole by expanding, then recoiling during diastole, to release the energy and keep blood moving continuously.
List the three sources of energy available to a contracting muscle. Then list the type best suited for instantaneous energy consumption.
What are creatine phosphate, cellular respiration, and glycolysis followed by fermentation?
and
What is creatine phosphate?
Despite lacking troponin, explain the way calcium still aids smooth muscle contraction.
Calcium binds to calmodulin, forming a Ca²⁺-calmodulin complex that activates MLCK, which phosphorylates the myosin head to allow actin binding.
Define cardiac output and the formula used to calculate it. A: Cardiac output is the volume of blood ejected per minute; CO = HR × SV
What is the volume of blood ejected per minute (CO = HR × SV)?
(bonus: define HR and SV)
Increased blood distribution to skeletal muscle during exercise is an example of this process occurring.
What is intrinsic control (because of an increase in products made by an increase of metabolic processes)?
A drug blocking L-type calcium channels in cardiac contractile cells would have this effect on the strength of contraction.
Contraction would weaken because less Ca²⁺ would enter the cell, reducing Ca²⁺-induced Ca²⁺ release from the SR and decreasing cross bridge cycling