VERIFIED ANSWERS FOR A GUARANTEED PASS
Hypokalemia - ✅✅When the resting membrane potential becomes more
negative as a result of a decrease in extracellular potassium concentration (Book)
it is termed hyper-polarization.
Calcium and Excitation-contraction coupling is the process by which an action
potential arriving at the plasma membrane of the muscle fiber triggers the cycle
leading to cross-bridge activity and contraction. (Book) - ✅✅It enters the
myocardial cell from the interstitial fluid after electrical excitation, which increases
the membrane permeability to calcium. Two types of calcium channels (L-type and
T-type) are identified in cardiac tissues.
Calcium interacts with troponin C which causes tropomyosin to move thus
allowing actin and myosin to work together to cause contraction. (Lecture) -
✅✅The greater the amount of intracellular calcium the stronger the contraction.
Hypercalcemia - ✅✅Because serum calcium levels are increased, a greater
amount of calcium is also contained inside the cells. The threshold potential
becomes more positive (hyperpolarized) (e.g., moves from −60 to −50 millivolts)
and the cell membrane becomes refractory to depolarization (decreased
excitability).
,Hypocalcemia manifestations - ✅✅there is an increase in neuromuscular
excitability
Hypocalemia manifestations - ✅✅Two clinical signs are Chvostek sign and
Trousseau sign. Chvostek sign is elicited by tapping on the facial nerve just below
the temple. A positive sign is a twitch of the nose or lip. Trousseau sign is
contraction of the hand and fingers when the arterial blood flow in the arm is
occluded for 5 minutes with the use of a blood pressure cuff. More severe forms
manifest tetany.
Myocardial relaxation (Lecture) - ✅✅intracellular calcium levels decrease.
Magnesium is required for (Book) - ✅✅the binding of ATP to the myosin site.
Hypomagnesaemia: (Book) - ✅✅clinical manifestations include behavioral
changes, irritability, increased reflexes, muscle cramps, ataxia, nystagmus, tetany,
convulsions, tachycardia, hypotension. Because magnesium inhibits potassium
channels, loss of magnesium results in movement of potassium out of the cell, with
renal excretion resulting in hypokalemia.
Hypermagnesemia clinical manifestations(Book) - ✅✅clinical manifestations
include lethargy, drowsiness; loss of deep tendon reflexes; nausea and vomiting;
, muscle weakness; hypotension; bradycardia; respiratory distress; heart block,
cardiac arrest. Excess magnesium concentration depresses skeletal muscle
contraction and nerve function.
1. Explain the difference between cardiac hemodynamic measures Video Lecture:
Cardiac output - ✅✅Cardiac output is the amount of blood pushed from the left
ventricle in 1 minute. It is calculated by multiplying the heart rate in beats per
minute by the stroke volume.
Stroke Volume - ✅✅Stroke volume is the amount of blood ejected by the
ventricle for each cardiac cycle (heart beat).
Ejection fraction- The ejection fraction is the percentage of blood which is ejected
from the ventricle with each contraction. It is calculated by dividing the stroke
volume by the end diastolic volume.
Ejection fraction - ✅✅The ejection fraction is the percentage of blood which is
ejected from the ventricle with each contraction. It is calculated by dividing the
stroke volume by the end diastolic volume.
Ejection fraction - ✅✅The ejection fraction is the percentage of blood which is
ejected from the ventricle with each contraction. It is calculated by dividing the
stroke volume by the end diastolic volume.