Unit 3: Human Blood Circulatory System — Short Questions

(i) Red Blood Cells (Erythrocytes)
RBCs contain a red protein, haemoglobin which transports oxygen and little amount of carbon dioxide.
(ii) White Blood Cells (Leukocytes) WBCs
defend the body against diseases.
(iii) Platelets help in blood clotting.

Atria Ventricles
(i) The upper chambers of the (i) The lower chambers of the
heart are called atria. heart are called ventricles.

(ii) The atria have thinner walls (ii) The ventricles have thicker
as compared to ventricles. walls as compared to atria.

Superior and inferior vena cava → right atrium → right ventricle → lungs → left atrium → left ventricle → aorta → all parts of body.

(i) Causes: A blockage in one or more coronary arteries that forms over atherosclerotic plaques.

(ii) Treatment: Emergency treatment involves medicines to dissolve clots, angioplasty to open blocked arteries and stenting to keep arteries open.

Diagram showing heart in Systole and Diastole with labels: Tricuspid & bicuspid closed, Semilunar closed

(i) Transporting oxygen and nutrients to the lungs and tissues.
(ii) Forming blood clots to prevent excess blood loss
(iii) Carrying cells and antibodies that fight infection.
(iv) Bring waste products to the kidneys and liver, while filter and clean the blood.
(v) Regulating body temperature.
(vi) Protect us by producing antibodies.

1. Types of White Blood Cells
WBCs can be divided into two main types:
(a) Granular leukocytes: These are of three types, neutrophils, eosinophils and basophils.
(b) Agranular leukocytes: These are of two types i.e. monocytes and lymphocytes.
2. White blood cells are transparent. To distinguish them from red blood cells they are called white blood cells.

Agranulocytes are type of white blood cells in which the cytoplasm is clear. These are of two types i.e., monocytes and lymphocytes.

(i) Monocytes
These are phagocytic and ingest bacteria and dead cells at the damaged tissue region.
(ii) Lymphocytes
There are two types of lymphocytes. B Lymphocytes protect us by producing antibodies. T-lymphocytes directly destroy any cell that bears antigens.

Basophils B-lymphocytes
(i) It is a type of granular (i) It is a type of a-granular
leukocyte. leukocyte.

(ii) Basophils release histamine (ii) B-lymphocytes protect us by
in injured tissue and in producing antibodies.
allergic response.

Serum Blood
When a blood clots, fibrinogen Blood is a specialized body
is separated from blood plasma. fluid, a connective tissue that
The rest of blood is called is composed of a liquid called
serum. blood plasma and blood cells.

Red blood cells White blood cells
(i) These are called (i) These are called leukocytes.
erythrocytes.

(ii) A single RBCs is a circular (ii) Each white blood cell is
flattened, biconcave disc irregular in shape and contains
and has no nucleus. a nucleus.

(iii) Their life span is 120 days. (iii) Their span is 3-4 days.

(iv) RBCs carry oxygen and also (iv) Following types of WBCs
transport a small amount of perform different functions:
carbon dioxide • Eosinophils are involved in the
control of allergic reactions.
• Basophils release histamine in
injured tissue and in allergic
response.
• Neutrophils engulf pathogens
during phagocytosis.
• Monocytes are phagocytic and
ingest bacteria and dead cells
at the damaged tissue region.
• B-Lymphocytes protect us by
producing antibodies.
• T-Lymphocytes directly destroy
any cells that bear antigens.

Tricuspid valve Bicuspid valve
(i) Tricuspid valve is present (i) Bicuspid valve is present
between right atrium and between left atrium and left
right ventricle. ventricle.

(ii) This valve prevents the back (ii) This valve prevents the back
flow of blood into the right flow of blood into the left
atrium. atrium.

(iii) Closure of tricuspid valve (iii) Closure of bicuspid valve
produces "lubb" sound. produces "lubb" sound.

Valves prevent the back flow of blood in various parts of the heart. For example, bicuspid valve prevents backflow of blood from left ventricle to left atrium.

Since we know that atria receive blood from various parts of the body and ventricles pump blood to various parts of the body, pumping require more pressure and force so to withstand the pressure the walls of ventricle are thicker than atria walls.

The left ventricle of our heart is larger and thicker than the right ventricle. This is because it has to pump the blood further around the body and against pressure, compared with the right ventricle.

Upper thin walled chambers of the heart are called atria and period of contraction of atria is called atrial systole.

(i) Diastole
(ii) Ventricle
(iii) Ventricular Systole

Ans.
(i) The period of relaxation of heart chambers is called diastole.
(ii) Lower thick-walled chambers of heart are called ventricle
(iii) The period of ventricular contraction is called ventricular systole

Artery Vein
(i) Transport blood away from (i) Collect blood from body
the heart to the various through capillaries and
parts of the body through transport it towards heart.
capillaries.

(ii) All arteries carry (ii) All veins carry deoxygenated
oxygenated blood except blood except pulmonary veins
pulmary arteries

(iii) There are no valves in them (iii) Valves are present only below
except at the base of the heart region of the body.
pulmary trunk and aorta. These prevent the back flow of
blood.

(iv) Have high blood pressure (iv) Have low blood pressure

(v) Pulse can be detected (v) No pulse

(vi) Have smaller lumen and thick (vi) Have larger lumen with thin
wall walls

(vii) Thick muscle layer (vii) Thin muscle layer

Arteries carry blood away from the heart, while arterioles are the smallest arteries which transport blood from arteries to capillaries.

Colour of the arteries appears to be red due to the bright red oxygenated blood flowing through them.

Blood vessel I is artery and Blood vessel II is vein.

Pulmonary artery Pulmonary vein
Pulmonary arteries carry Pulmonary veins carry oxygenated
deoxygenated blood from the blood from the lungs back to the
heart to lungs for oxygenation. heart.

Coronary refers to the arteries of the heart. This circuit provides the heart muscle with oxygenated blood. The coronary circuit then returns deoxygenated blood to the heart's right upper chamber (atrium) to send to the lungs for oxygen

(a) Head
(b) Liver
(c) Kidney
(d) Hind limb
(e) Heart

Ans.
(a) Carotid arteries
(b) Hepatic artery
(c) Renal arteries
(d) Common Iliac arteries
(e) Coronary arteries

The largest artery in the systemic circuit is the aorta. The aorta ascends and forms an aortic arch which branches into arteries leading to the organs. As aorta passes down through the thorax, it becomes the dorsal aorta which gives many branches to supply blood to different organs of the body.

Arteriosclerosis is the hardening of arteries. While atherosclerosis is the deposition of materials in the arteries. The deposition of cholesterol is called plaques which increase in size and begin to block arteries. Plaques can cause a clot formation on the irregular arterial wall.

Angina Pectoris (commonly called Angina) is chest pain or discomfort caused by reduced blood flow to the heart muscle, typically due to coronary artery disease. Angina is a symptom of CHD and often indicates that the heart is not getting enough blood.

1. Symptoms: Chest pain or discomfort, chest pressure and squeezing, or fullness. Pain can radiate to the shoulders, neck, or arms.
2. Treatment: Lifestyle medications, procedures like angioplasty or stent placement.
3. Complications: If untreated, can progress to myocardial infarction and increase the risk of heart failure.

Myocardial Infarction Silent Heart attack
"Myocardium" means heart muscle Sometimes heart attack occurs
and "Infarction" means tissue without symptoms. It is called
death. The death of heart muscles silent heart attack. It is more
is called myocardial infarction. common in the elders and in
It is commonly known as a "heart patients with diabetes.
attack". It occurs when blood flow
to a part of the heart muscle is
blocked for a prolonged period,
leading to death of the heart
muscle. Myocardial infarction
occurs with symptoms.

Oxygenated blood is separated from deoxygenated blood in the heart to create a highly efficient double circulatory system, ensuring tissues receive fully oxygenated blood for maximum energy production, supporting warm blooded nature and maintaining high metabolic rates needed for complex activities.

Regular exercise strengthens circulatory system by making your heart a more powerful pump, improving blood vessel flexibility, increasing blood volume and boosting oxygen delivery, leading to lower blood pressure, better cholesterol level and reduced risk of heart disease.

Strategies to prevent heart diseases.

• Don't smoke or use tobacco
• Get moving: Aim for at least 30 - 60 minutes of activity daily.
• Eat a heart-healthy diet.
• Maintain a healthy weight.
• Get quality sleep.
• Manage stress.
• Get regular health screening tests.

If cholesterol levels are never regulated, the excess cholesterol builds up sticky plaque in arteries causing atherosclerosis which hardens and narrows blood vessels restricting oxygen-rich blood flow to the heart and brain, leading to chest pain (angina), heart attack, strokes and ultimately severe cardiac vascular disease and potential organ damage due to oxygen deprivation.