Question

Why do some but not all animals have a circulatory system? What circulatory system? What are additional functions?

What are the components common to all animal circulatory systems? What’s the difference between and open and closed circulatory system?

What’s the difference between single circulation and double circulation? How does this relate to two-, three-, and four-chambered hearts? What is the third circuit?

Be able to trace the path of blood through the heart and lungs. Where are AV valves and semilunar valves? When are they open?

Where doe the nerve impulse that signals cardiac contraction begin? Is input from the central nervous system required? Where and why does a delay happen? How does the signal travel to the ventricles?

What is the basic structure of arteries and veins? What do they have in common? How are they specialized for their individual function? What is different about the structure of capillaries? How does its structure suit its function?

Where is blood pressure and velocity highest? Where are they lowest? Why does it change throughout the circulatory system?

What are the cellular and noncellular components of blood?

What is coronary artery disease (CAD)? What role does atherosclerosis play in CAD? How does
atherosclerosis lead to heart attack?

What are the risk factors for cardiovascular disease? How can it be treated or prevented?

Answer 1

Ans 1) Unicellular organisms do not have circulatory system as these organisms do not have specialised respiratory organs as the carbon dioxide and oxygen are directly diffused into the tissues and outside environment.
Ans 2-) Circulatory system is defined as the organ system which allows the circulation of blood in the body. Also, transport of oxygen, carbon dioxide, nutrients and hormones occurs in the cells of the body in order to provide nourishment to the cells.
Ans 3-) Functions of circulatory system
1. Helps in transport of various nutrients, hormones, and oxygen to cells along with the removal of wastes which are metabolic
2. It helps in protection of body as it will circulate various proteins which will help the body to defend itself from the action of toxins and foreign micribes.

Ans 4) the right components and the left components of circulatory system are common components in all animals.

Ans5-) Open circulatory system
It is a type of circulatory system in which blood do no flow inside the blood vessels.
Closed circulatory system :
In this the blood flows within the vessels.

Ans6-) Single circulation is defined as the circulatory system in which the blood flows only once through the heart.
Double circulation is defined as the flow of blood twice through the heart.
Ans 7-) ln three chambered heart, the blood is pumped through two atria and one ventricle
Four chambered heart- the most efficient heart is present in birds and mammals. It can separate the oxygen rich blood that is oxygenated blood and carbon dioxide rich blood that is deoxygenated blood. Oxygen rich blood is pumped to every organ of the body whereas the deoxygenated blood is pumped back to the lungs.
Ans 8-) The three circuit of circulatory system of mammals are - The pulmonary circuit, the systemic circuit and the coronary circuit
Systemic circuit viens pump the blood to the heart right atrium which then pump to right ventricle.
Path of blood flow
Blood travels from pulmonic valve to pulmonic artery which them pumped to lungs where the purification of blood occurs and the oxygenated blood is pumped back to left atrium.

Ans 9) AV valves or antrioventricular valves are present in between the ventrical and the atria. Semilunar valves are present in both between the left ventrical and the aorta and between right ventrical and pulmonary artery.

Ans 10) The AV valves or the antrioventricular valves opens at the time of diastole and the semilunar valves opens at the time of systole.

Ans 11) The starting of nerve impulse take place in the SA node (sinoatrial) of heart through electric signals.

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