The Circulatory System

Both A and R are false.

Explanation — Arteries carry blood away from the heart to different organs of the body. They supply oxygenated blood to most organs of the body except lungs because lungs already contain enough amount of oxygen.

Both A and R are false.

Explanation — Blood is responsible for transporting nutrients and excretory wastes, along with the respiratory gases (oxygen and carbon dioxide) throughout the body. Lymph vessels do not carry the respiratory gases as lymph contains WBCs only. Absence of RBCs (i.e. Haemoglobin) makes them unable to carry oxygen or carbon dioxide.

A is false and R is true.

Explanation — Pulmonary artery carries deoxygenated blood from the right ventricle of the heart to the lungs.

Both A and R are true.

Explanation — The atria have thinner walls as they only need to pump blood a short distance into the ventricles. Ventricles are bigger in size and their walls are thicker, elastic and muscular so as to efficiently pump blood to different parts of the body with much greater force.

Both A and R are true.

Explanation — Capillaries play a crucial role as this interconnection is crucial for the exchange of essential substances like water, nutrients, waste products, and respiratory gases from arteries to veins and vice-versa.

Difference between Pulmonary artery and Pulmonary vein on the basis of the kind of blood:

Difference between Artery and Vein on the basis of direction of blood flow:

Difference between Closed and Open Vascular system on the basis of definition:

Difference between Bicuspid and Tricuspid valve on the basis of location:

Difference between Blood and Lymph on the basis of composition:

The four heart related conditions common to humans along with their cause and symptoms are given below:

1. Palpitations — When the heart beats too hard or too fast or sometimes even skips a beat, it is called Palpitations. Palpitations are often caused due to stress or anxiety. Sometimes, certain types of food may also cause Palpitations.
2. Hypertension — This is a condition that occurs when blood flows through the blood vessels with a force greater than normal. This is also called High Blood Pressure. Hypertension can also strain the heart, damage blood vessels and increase the risk of heart attack or stroke.
3. Heart attack — A heart attack is a sudden interruption of blood supply to the heart. It usually occurs due to a blood clot that prevents the flow of oxygen rich blood to the cardiac muscle. As, a result a part of the cardiac muscle dies and causes a permanent damage to the heart. Some common symptoms of a heart attack include uncomfortable pressure, tightness or squeezing pain in the centre of the chest, discomfort or pain spreading beyond the chest to the shoulders, neck, jaw, teeth or one or both arms, shortness of breath , dizziness, sweating and nausea.
4. Cardiac Arrest — A cardiac arrest occurs when the heart suddenly stops pumping blood around the body. In cardiac arrest, a person suddenly loses consciousness and stops breathing or may have abnormal breathing. Some people experience chest pain, shortness of breath, or nausea before a cardiac arrest occurs. The common cause of cardiac arrest is coronary artery disease wherein the walls of the arteries thicken as a result of fat or plaque deposition. Less common causes include major blood loss, lack of oxygen, low potassium levels, heart failure and intense physical exercise.

(a) Universal donor — The blood of O group can be given to all the groups. As blood group O has neither antigen A nor B so it doesn't cause self-clumping with any antibodies making it compatible with all blood groups. Hence, a person with O blood group is called a universal donor.

(b) Universal recipient — A person with blood group AB is called a universal recipient since they can receive blood from a person with any blood group. As blood group AB has no antibodies, so there is no attack on the antigens of any blood group making it compatible to receive blood from all blood groups.

This process is known as blood transfusion. The following precautions are to be observed for blood transfusion:

1. Checking the compatibility of the donor's blood group with that of the recipient.
2. It should be made sure clinically that the blood of the donor is free from any infections.
3. The donor's hemoglobin level is checked.

The parts marked 1 to 6 are labelled below:

• 1 → Left pulmonary artery

• 2 → Superior vena cava

• 3 → Left pulmonary vein

• 4 → Right auricle

• 5 → Left ventricle

• 6 → Right ventricle

(a) Deoxygenated blood is carried by the blood vessel marked 2 (Superior vena cava).

(b) Aorta

(c) Right auricle

(a) Septum

(b) SA node (Sinoatrial Node)

(c) Karl Landsteiner

Pulmonary vein

Reason — Pulmonary vein are the blood vessels which carry oxygenated blood from lungs to the heart.

RA → RV → Pulmonary arteries → Lungs → Pulmonary veins → LA

Reason — Pulmonary circulation is the movement of blood from the heart to the lungs for oxygenation, then back to the heart again. At first, blood flows from the right side of the heart to the lungs and then returns to the left side of the heart (pulmonary circulation).

Only P and R

Reason — Blood group 'AB' has antigens A and B so people with AB blood group can receive blood from all types, while Blood group 'O' has neither antigen A nor B, so people with blood group O can give their blood to all the groups but can only receive blood from O blood types. Hence, a person with AB blood group is called a universal recipient, and a person with O blood group is called a universal donor.

Palpitations

Reason — Palpitations are caused by stress or anxiety. Sometimes certain types of food may also cause palpitations.

Three components of the circulatory system:

1. Heart
2. Blood vessels
3. Blood

Four blood groups on the basis of antigen are:

1. A (A antigen)
2. B (B antigen)
3. AB (A and B antigens)
4. O (No antigens)

Two phases of double circulation:

1. Systemic circulation.
2. Pulmonary circulation.

Three principal fluids of the human body:

1. Blood
2. Lymph
3. Tissue fluid

Three kinds of blood vessels are:

1. Arteries
2. Veins
3. Capillaries

Two types of blood circulation are:

1. Pulmonary circulation
2. Systemic circulation

The circulatory system comprises of the heart, blood and blood vessels which circulates blood throughout the body, thereby helping in the transport of nutrients, oxygen and carbon dioxide.

Blood is the circulating fluid contained in the heart and in the blood vessels such as arteries, veins and capillaries of the circulatory system. It helps in the transport of oxygen, carbon dioxide and digested food.

Lymph is the fluid contained within the lymph vessels and lymphatic organs. It is also a part of immune system and its main function is defence against germs.

Sometimes a mechanical device called an artificial pacemaker is placed surgically in humans if their SA node is damaged or if the electrical conduction system of the heart has problems.

Lungs

The left side of the heart contains oxygenated blood.

Pericardial fluid protects the heart from shocks, jerks or any mechanical stress.

Aorta carries oxygenated blood from the heart to all parts of the body through its branches.

The two Vena Cavae veins (Superior Vena Cava and Inferior Vena Cava) bring deoxygenated blood from all the different parts of the body to the right auricle of the heart.

Functions of lymph are —

1. Drainage — It drains away excess tissue fluid and metabolites and returns proteins to the blood from tissue spaces.
2. Absorption — Fats in the intestine are absorbed through lymph vessels (or lymphatics).
3. Defence — Lymphocytes and monocytes of the lymph function to defend the body. The lymphatics also remove bacteria from the tissues.