Describe the physiological basis for the positive inotropic effect of digoxin on the heart. How does this explain the therapeutic benefit of the drug?

Digoxin is a sodium potassium adenosine triphosphatase (Na+/K+ ATPase) inhibitor.

Digoxin is a group of drug that has most effects on cardiac tissues. Digoxin was first isolated from the plant Digitalis lantana that was found to be a sodium potassium adenosine triphosphatase (Na+/K+ ATPase) inhibitor. This drug when taken through mouth, gives a 60 to 80% bioavailability .

This drug blocks the sodium potassium adenosine triphosphatase (Na+/K+ ATPase) pumps of the myocardium. When the sodium pumps are closed, this leads to the increase in extracellular levels of sodium.

As the extracellular sodium increase, this indirectly blocks the sodium calcium exchanger which in normal conditions exchange 1 intracellular calcium in exchange of 3 extracellular sodium ions.

As this pump is blocked, this leads to increase in intracellular levels of calcium. This calcium levels also increase in the sarcoplasmic reticulum. Thus, the contractibility of the heart muscles per beat increase which helps to pump blood more effectively. Thus, the effect seen is positive intropic effect.

the correct option is option d

question#1

ans:

cell is the basic unit of organization of all living things. cells are often called the building block of life and it is the smallest unit of life. the study of cell is called cell biology. cell consists of cytoplasm enclosed within membrane, which contain bio-molecules such as proteins and nucleic acid.

two third of cell is water, which means that two-third of your whole body is water. the rest is the mixture of molecules, mainly proteins, lipids and carbohydrates.

question#2

ans:

organ:

an organ is a group of tissues specialized to form a functional unit. an example is the heart in animals.

organ system:

an organ system is a group of several organs whose functions are synchronized to release an effective action in a living organism. an example is digestive system.

question#3

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#4

different systems perform different function at tissue level. for example, the respiratory system facilitates breathing. in the alveoli tissue of the lungs, the exchange of oxygen and carbon dioxide molecules between the air and the bloodstream occurs by passive transport, so that oxygen is taken in and carbon dioxide and water are removed. different systems of the body carry out different functions. for example, your digestive system is responsible for taking in and processing food, while your respiratory system—working with your circulatory system is responsible for taking up oxygen and getting rid of carbon dioxide.

question#5

our body works because of the interactions that happen between organs and organ systems.  

for example:  

the heart to regulate blood flow throughout the body. the blood carries oxygen and nutrients to the cells and carries carbon dioxide and waste away from the cells. body systems work together in maintaining a constant internal environment. when this balance is disrupted, the body systems may not function properly, and human health can suffer.   you start to feel bad.