CBSE Class 5 Science The Circulatory System MCQs

Question: How many major organ in our body?
a) 5
b) 6
c) 7
d) 8
Answer: 5

Question: Brain, spinal cord and nerves make our _________ system.
a) Nervous
b) Skeletal
c) Muscular
d) all of these
Answer: Nervous

Question: Bones, cartilage, ligaments make our ________ system.
a) Skeletal
b) Muscular
c) none of these
d) Nervous
Answer: Skeletal

Question: ________ system controls movement of all parts of our body.
a) both
b) Skeletal
c) Nervous
d) None of these
Answer: both

Question: Digestive system ________ our food.
a) Digests
b) absorbs
c) stores
d) none of these
Answer: Digests

Question: What is the main parts of excretory system?
a) kidneys
b) heart
c) liver
d) none of these
Answer: kidneys

Question: The blood, the blood vessels, and the heart are main parts of _________ system.
a) circulatory
b) muscular
c) none of these
d) skeletal
Answer: circulatory

Question: _________ carries oxygen and carbon dioxide.
a) Blood
b) Heart
c) none of these
d) Water
Answer: Blood

Question: Blood _________ waste from all parts of the body.
a) collects
b) stores
c) all of these
d) distributes
Answer: collects

Question: How many kinds of blood vessels in our body?
a) Two
b) Three
c) Four
d) One
Answer: Two

Question: _________ are thick walled blood Vessels.
a) Arteries
b) both
c) none of these
d) Veins
Answer: Arteries

Question: Veins are thin walled blood vessels that carry blood the heart.
a) back to
b) both
c) none of these
d) away from
Answer: back to

Question: _________ is the largest artery in human body.
a) Aorta
b) both
c) none of these
d) Vena cava
Answer: Aorta

Question: Superior vena cava which brings blood from the _________ of the body.
a) upper
b) lower
c) both
d) none of these
Answer: upper

Question: The heart is a _________ size organ in our
a) fist
b) small
c) none of these
d) big
Answer: fist

Question: How many chambers are there in human heart?
a) four
b) three
c) two
d) one
Answer: four

Question: What is called living pump of human body?
a) Heart
b) lungs
c) chest
d) all of these
Answer: Heart

Question: Generally Arteries carry _________ rich blood?
a) Oxygen
b) water
c) carbon dioxide
d) air
Answer: Oxygen

Question: Deoxygenated blood is also called _________ blood?
a) impure
b) blue
c) black
d) pure
Answer: impure

Question: Which instrument is used to hear heart beat?
a) Stetho scope
b) Microscope
c) Thermometer
d) none of these
Answer: Stetho scope

Question: Throbbing sensation due to blood rushing through arteries is called
a) Pulse
b) Heart beat
c) sneeze
d) none of these
Answer: Pulse

Question: To generate extra energy, body need extra
a) Oxygen
b) water
c) both
d) none of these
Answer: Oxygen

Question: Our heart beats _________ times a minute throughout life.
a) 70
b) 100
c) 60
d) 50
Answer: 70

THE CIRCULATORY SYSTEM

The main features of a circulatory system are:
1) A transport or circulatory fluid: Blood and Lymph
2) A system of tubes: Blood Vessels
3) A pumping mechanism: Heart

Structure and working of heart:
The human heart is triangular in shape. It is enclosed by two membranes called the pericardium which have a fluid in between to protect the heart from any shock.
• Two upper chambers: Auricles (Separated by interatrial septum)
• Two lower chambers: Ventricles (Separated by interventricular septum)
• Ventricles are thick-walled because they pump blood out with force. The left ventricle specifically is the thickest because it pumps blood to organs far away from the heart.
• Each atria opens into the ventricle of its side through an atrio-ventricular aperture which is guarded by a valve.
• Bicuspid Valve: Present between the left atrium and left ventricle. Also known as Mitral Valve.

Consists of 2 flaps or cusps.
• Tricuspid Valve: Present between the right atrium and right ventricle. Consists of 3 flaps.
• Valves are attached to chordae tendinae which are in turn attached to the papillary muscles of the ventricles.
• Heart is made up of Cardiac Muscle Fibres.
• Pulmonary Semi-Lunar Valve: Present at the base of the pulmonary artery. Consists of 3 flaps.
• Aortic Semi-Lunar Valve: Present at the base of the aorta. Consists of 3 flaps.
• Superior and inferior vena cava: Brings deoxygenated blood to the right atrium.
• Pulmonary Vein: Brings oxygenated blood from the lungs to the left atrium.
• Pulmonary Artery: Brings deoxygenated blood from right ventricle to the lungs.
• Aorta: Carried oxygenated blood from the left ventricle to the rest of the body.

Blood vessels:
Heart—Artery—Arteriole—Capillary—Venule—Vein—Heart
The exchange of food material, gases and wastes takes place through the capillaries.

1. Arteries:
• Three layers: External, Muscle(thick) and Endothelium
• Thick walls and narrow lumen
• Thick and elastic in order to withstand high pressure of blood coming from heart

2. Veins:
• Thin muscle layer.
• Thin walls and large lumen.
• Contain semi-lunar valves to prevent backflow of blood

3. Capillaries:
• Smallest blood vessels.
• Only have one layer: Endothelium
• Permeable to water and small molecules only.

Composition of Blood:
• Two components: Plasma and Cells
• Three types of cells: RBCs(Erythrocytes), WBCs(Leucocytes), and Platelets(Thrombocytes)
• Blood Plasma is pale yellow and slightly alkaline.

1. RBCs:
• Biconcave and have no nucleus.
• Red due to presence of haemoglobin.
• Transport oxygen
• Formed in red bone marrow
• No nucleus provides more space in cell for haemoglobin
• Absence of mitochondria so that oxygen is not utilized by the cell itself
• Biconcave shape provides more surface area for the diffusion of gases and also helps them flow through thin capillaries in a single line.
 

2. WBCs:
• Round or irregular in shape, and have nucleus.
• Colorless
• Destroy harmful germs by engulfing them by phagocytosis
• Formed in white bone marrow
• Two main types: Granulocytes and Agranulocytes

• Granulocytes: Eosinophils, Basophils and Neutrophils
• Agranulocytes: Monocytes and Lymphocytes
• Diapedesis: Squeezing out of WBCs from blood capillaries

3. Platelets:
• Very small and irregular in shape with no nucleus.
• Colorless
• Help in clotting of blood
• Formed in large bone marrow cells

Lymph and Tissue Fluid:
• Tissue Fluid: Fluid present in the intercellular cells of the capillaries.
• Lymph Capillaries: Tiny, thin-walled, blind ending tubes
• Lymph: Straw colored fluid that contains blood plasma without RBCs, platelets and plasma proteins.
• Contains special WBCs called Lymphocytes that fight against infection.
• Open circulatory system
• Unidirectional
• Bring tissue fluid back to heart
• Slow and low-pressure movement
• Tiny semi-lunar valves
• Examples of lymph nodes: Tonsils and Spleen
• Absorbs fats from intestine
• Collects waste products

Blood Coagulation:
• Blood platelets are responsible for clotting
• Thromboplastin—prothrombin—thrombin—fibrinogen—fibrin—blood clot Serum
• Serum in blood plasma without fibrinogen.
• Colorless and doesn’t clot

Blood Groups
• Agglutination: Clumping of cells due to antigen-antibody reaction
• Blood Group A: Contains A antigen and B antibody
• Blood Group B: Contains B antigen and A antibody
• Blood Group O: Contains no antigens and A&B antibodies
• Blood Group AB: Contains A&B antigens and no antibodies
• Rhesus Factor: Presence of a protein on the surface of RBCs
• Disease in fetus due to Rh Factor: erythroblastosis foetalis

Double Circulation:
• Blood passes through the heart twice to complete one circulation.
• One circulation is between the heart and body organs called Systematic Circulation.
• Other circulation is between the heart and the lungs called Pulmonary Circulation.

Portal System:
• It is a system in which a vein first collects blood from one capillary system and then branches out again into another capillary system.
• The vein involved is called a portal vein.

Cardiac Cycle:
• Systole: Contraction of heart chambers
• Diastole: Relaxation of heart chambers
• Joint Diastole: Relaxed state of both atria and ventricles
• Pulse: Wave of distention followed by constriction, felt in the arteries as a result of ventricular systole and diastole.
• Blood Pressure: Pressure exerted by blood against the walls of arteries
• Sphygomanometer: Used to measure blood pressure
• Sinoatrial Node: Pacemaker; Generates each wave of cardiac impulse.