PHYSIOLOGY OF THE CIRCULATORY SYSTEMEffect of Ions on the Rate of Heartbeat

INTRODUCTION Sodium, Potassium and Calcium required to maintain the body's normal

health. any imbalance between them can

cause serious problems The heart is an organ that is

particularly vulnerable to changes in the ratios of these elements in the blood.

known as electrolytes because once released from a bound state, they become ions in a water environment. Electrolytes are able to conduct electricity.

METHODOLOGY

30 mL Ringer’s Solution

Excised Heart

Totally pith a frog

Open the Ventral side of the body

Remove Pericardium

Lift and cut the blood vessels above the heart

Transfer Fresh Ringer’s

Solution

Swirl

Record Heart rate

30 ml Ion Solution

100 mL beaker

Record Heart rate

Repeat for 3 trials

Calculate average for the 3 trials

Perform the procedures using these solutions:• 0.6% sodium chloride• 0.15% potassium

chloride• 0.012% calcium

chloride

RESULTS• 0.6% sodium chloride

Trials Ringer’s Solution (beats per minute)

Sodium Chloride (beats per minute)

1 63 54

2 63 63

3 63 66

Average 63 61

RESULTS• 0.15% potassium chloride

Trials Ringer’s Solution (beats per minute)

Potassium chloride (beats per minute)

1 86 74

2 57 23

3 38 12*

Average 60 36

RESULTS• 0.012% calcium chloride

Trials Ringer’s Solution (beats per minute)

Calcium chloride (beats per minute)

1 88 74

2 83 66

3 77 65

Average 83 68

DISCUSSION heart muscle cells depend on minute regulated electrical impulses that are

created when charged atoms -- or ions -- pass through complex molecular channels inside and between cells

one litre of Ringers Lactate solution contains: 130 mEq of sodium ion = 130 mmol/L 109 mEq of chloride ion = 109 mmol/L 28 mEq of lactate = 28 mmol/L 4 mEq of potassium ion = 4 mmol/L 3 mEq of calcium ion = 1.5 mmol/L

DISCUSSION• Theoretical

Result

DISCUSSION The fluids perfusing the heart must contain a proper balance of the three essential ions the heart is able to maintain its normal contracti1ity for hours in an oxygenated environment excess of potassium ions in the fluids perfusing the heart causes the heart to become dilated

and slows the heart rate. Too much increase in potassium ions may completely block conduction of impulse from atria to ventricles through AV bundle and may stop heart during diastole.

excess sodium ions depresses cardiac function like potassium ions excess but for an entirely different reason. Sodium ions compete with the calcium ions at the same point in the excitatory or contractile process of the heart muscle in such a way that greater the sodium ions concentration in the fluids perfusing the heart, the less the effectiveness of calcium ions in causing contraction.

calcium ions in the fluids enhance myocardial contractility When large amount of calcium ions are infused into the experimental animals, the heart relaxes less during diastole and eventually stops in systole (calcium rigor). A deficiency of calcium ions causes cardiac flaccidity.

DISCUSSION Hypernatremia

excess sodium levels in the blood in relation to water Caused by lack or little water intake or loss of water due to diarrhea and/or vomiting.

Hyponatremia This occurs when there is an increase in the amount of body water in relation to sodium. This occurs with diseases of the liver, kidney, burn victims and those who suffer from

congestive heart failure and other conditions. Hyperkalemia

An abnormal increase in potassium disorders that decrease the function of the kidneys can result in hyperkalemia

Hypokalemia decrease in potassium occur due to kidney disease, diarrhea, eating disorders, heavy sweating, prescription

drugs, vomiting or other causes.

DISCUSSION Hypercalcemia 

results from alkalosis, hyperparathyroidism, or hypothyroidism. causes muscular weakness, depressed reflexes, and cardiac arrhythmia

Hypocalcemia  results from vitamin D deficiency, diarrhea, pregnancy, lactation, acidosis,

hypoparathyroidism, or hyperthyroidism. increases the sodium permeability of plasma membranes, causing the nervous

and muscular systems to be overly excitable. Tetany occurs.

CONCLUSION The concentrations of these particular ions(K,Na,Ca) within the

extracellular environment may have a significant influence on cardiac function.

Excess sodium ions depress the function of the heart Excess potassium ions reduces the heart rate as well as strength of

contraction Excess calcium ions cause spastic contraction of the heart In instances where their concentration becomes excessive or deficient,

cardiac function may be seriously affected or arrhythmia (irregular heartbeat) could occur.

REFERENCES http://www.slideshare.net/JenSambo/bio-22-lab-expt-19-group-4. Retrieved

October 29, 2014 http://www.drstandley.com/labvalues_electrolyte.shtml. Retrieved October

29, 2014

https://www.inkling.com/read/anatomy-and-physiology-kenneth-saladin-6th/chapter-24/electrolyte-balance. Retrieved October 29, 2014

http://en.wikipedia.org/wiki/Ringer's_solution. Retrieved October 29, 2014