Question 1 PART 1: Explain the effects of hyperkalemia on the heart. Be sure to

Question

Question 1

PART 1: Explain the effects of hyperkalemia on the heart. Be sure to note whether hyperkalemia causes depolarization or hyperpolarization of the heart cells. Be sure that you explain how this affects the contraction (EKG readout) of the heart.

PART 2: Explain at least two fundamental differences between SKELETAL muscle tissue and CARDIAC muscle tissue. You may choose to comment on their Anatomical differences or physiological differences.

PART 3: Explain how angina pectoris (“choked chest”) is different from a myocardial infarction (MI, also known as a “heart attack”)

Question 2

Consider the ARTERIOLE end of a capillary.
Diagram or otherwise explain the pressures that drive fluid flow across a capillary (out of the capillary and back INTO the capillary). Be sure to include the terms “capillary hydrostatic pressure” and “interstitial/tissue hydrostatic pressure” and “capillary oncotic (osmotic) pressure.” Also, be sure to mention “net filtration pressure” in your explanation.

Considering the VENULE side of a capillary, explain how hydrostatic and oncotic (osmotic) pressures have CHANGED from the arteriole side. In other words, what forces are primarily important in allowing fluid to be reabsorbed from the tissue and back into the veins?

Explanation / Answer

.1)part1

effects of Hyperkalemia on the heart :Hyperkalemia occurs when the concentration of potassium (K+) in the bloodstream exceeds a threshold value, throwing the body's internal pH balance out of work . hyperkalemia causes persistent  depolarizationof the heart.extracellular K is high prevent the passive flow,more K in the cell depolarization .in cardiac pacemaker cells during phase IV ,due to high K+ permeability it will effectively counteract hyperpolarization induced depolarizing current rectifier channels therefore late approach towards threshold .While mild hyperkalemia probably has a limited effect on the heart, moderate hyperkalemia can changes in the electrocardiogram EKG, recording EKG is an electrical reading of the activity of the neuromuscular activity of the heart, and severe hyperkalemia can cause the heart to stop beating.

PART 2:

1)the cardiac muscles are semi-spindle, the skeletal muscles are cylindrical in shape.

2)The skeletal muscle cells are longer than the cells of the cardiac muscle.

3)When the skeletal muscles are multi-nucleated, the cardiac muscles have one or two nuclei.

PART 3:

angina pectoris (“choked chest”):it is thoracic pain caused by the fleeting deficiency of blood to the heart musculature. In an attack of angina, the myocardial cells weaken from a temporary lack of oxygen. The sharp, squeezing pain of angina pectoris typically lasts for no more than a few minutes and may not recur for months.they cause cardiac arrest ,and heart attack.it is of two types

1)Unstable angina

2)Prinzmetal angina.

Myocardial infarction (MI) :it is commonly known as heaart attack.  Myocardial infarction occurs when the coronary arteries are blocked by a blood clot.twocoronary arteries delivery oxygenated blood to the heart, and if one of these two arteries fail or become blocked, then a portion of the heart will not acquire the necessary oxygen. This clot could be because of CAD, which happens when the inner walls of the coronary arteries thicken because of build up of cholesterol.

2) the pressures that drive fluid flow across a capillary out of the capillary and back in to the capillary are

capillary

Hydrostatic pressure:

is a force generated by the pressure of fluid on the capillary walls either by the blood plasma or interstitial fluid.

interstitial/tissue hydrostatic pressure:

hydrostatic pressure exerted on the capillary in the interstitial fluid. This value is negligible in most tissue fluids of the body is called interstitial/tissue hydrostatic pressure.

capillary oncotic (osmotic) pressure:Oncotic pressure is a form of osmotic pressure exerted by proteins either in the blood plasma or interstitial fluid.

net filtration pressure:The net filtration pressure is the balance of the four Starling forces and determines the net flow of fluid across the capillary membrane.

The forces are primarily important in allowing fluid to be reabsorbed from the tissue and back into the veins is

Hydrostatic Pressure :This pressure drives fluid out of the capillary and is highest at the arteriolar end of the capillary and lowest at the venular end. Depending upon the organ, the pressure may drop along the length of the capillary by 15-30 mmHg (axial or longitudinal pressure gradient). The axial gradient favors filtration at the arteriolar end (where PC is greatest) and reabsorption at the venular end of the capillary (where PC is the lowest).

oncotic (osmotic) pressure:The oncotic osmotic pressure of the interstitial fluid depends on the interstitial protein concentration and the reflection coefficient of the capillary wall. The more permeable the capillary barrier is to proteins, the higher the interstitial oncotic pressure. This pressure is also determined by the amount of fluid filtration into the interstitium.

ures :

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