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Basics of blood and heart - class-VII

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The portion of heart which doesn't receive proper blood supply becomes

  1. Strong

  2. Dead

  3. Weak

  4. Diseased


Correct Option: C
Explanation:
When the heart tissue does not receive an adequate blood supply, it cannot function. The heart muscle weakened due to lack of food and oxygen. Improper supply of blood to heart usually causes pain and infected portion of muscles may die.
So the correct answer is 'Weak'.

Read the following statements carefully.
$(1)$ In fishes the heart pumps out deoxygenated blood which is oxygenated by the gills and supplied to the body parts from where deoxygenated blood is returned to the heart
$(2)$ The openings of the right and the left ventricles into the pulmonary artery and the aorta respectively are provided with the mitral valves.
$(3)$ The nodal musculature has the ability to generate action potential without any external stimuli, i.e., it is auto-excitable
$(4)$ The T-wave of ECG represents depolarization of the ventricles
Which of the given two statements are correct?

  1. $1$ and $3$

  2. $2$ & $4$

  3. $1$ and $2$

  4. $3$ & $4$


Correct Option: A
Explanation:

The correction in statements (2) and (4) are:

  • In vertebrates, the mitral valves are present between the left atrium and the left ventricle.
  • The T wave of ECG represents repolarization of the ventricles, not depolarization.
So, the correct answer is '1 and 3'.

Why it is necessary to separate oxygenated and deoxygenated blood in mammals and birds?

  1. To stop mixing of oxygenated and deoxygenated blood

  2. To maintain body temperature

  3. To suffice higher energy need

  4. All of the above


Correct Option: D
Explanation:

The heart of the higher organism is well equipped with the vascular system. the arteries carry the oxygenated blood while the veins carry the deoxygenated blood. This prevents the mixing of oxygenated and deoxygenated blood.

So, the correct answer is option A.

The upper chambers of the heart are called

  1. Auricles

  2. Ventricles

  3. Spiracles

  4. Tentacles


Correct Option: A
Explanation:

A normal heart has two upper and two lower chambers. The upper chambers, the right, and left atria, receive incoming blood. The lower chambers, the more muscular right, and left ventricles pump blood out of your heart.

So, the correct option is 'Auricles'.

When the muscles of the heart relax

  1. Blood flows from lungs into the left auricle

  2. Blood is pumped into the right auricle from all over the body

  3. Both a and b

  4. Blood flows from the left ventricle to the rest of the body


Correct Option: C
Explanation:

When the muscles of the heart relax, the right atrium receives deoxygenated blood from all parts of the body through superior, inferior vena cava and coronary sinus. The left atrium receives oxygenated blood from the lungs through two pairs of pulmonary veins. Thus option C is the correct answer. 

When the muscles of the heart contract?

  1. Blood is pumped from the right ventricle into the lungs.

  2. Blood flows from the lungs into the left auricle.

  3. Blood is pumped into the right auricle from all over the body.

  4. None of the above.


Correct Option: A
Explanation:

During ventricular systole, the deoxygenated blood from the right ventricle enters the pulmonary trunk, which carries blood to lungs for oxygenation. Thus option A is the correct answer. 

Which of the following statements is false?

  1. Oxygenated blood is pumped to all other parts of the body from left ventricle.

  2. Gaseous exchange in the alveoli happens through capillaries.

  3. Blood-from the right side of the heart enters into left side through right auricle and left auricle.

  4. Lungs oxygenate the deoxygenated blood.


Correct Option: C
Explanation:

The pulmonary artery arises from the right ventricle and carries deoxygenated blood to lungs for oxygenation. Lungs oxygenate the deoxygenated blood. This oxygenated blood is pumped to all parts of the body. Thus option C is the correct answer. 

The lower chambers of the heart are called

  1. Auricles

  2. Ventricles

  3. Spiracles

  4. Tentacles


Correct Option: B
Explanation:

The upper chambers are called the left and right atria, and the lower chambers are called the left and right ventricles. A wall of muscle called the septum separates the left and right atria and the left and right ventricles. The left ventricle is the largest and strongest chamber in your heart.

So, the correct option is 'Ventricles'.

.......... pumps deoxygenated blood to the lungs.

  1. Right auricle

  2. Right ventricle

  3. Left auricle

  4. Left ventricle


Correct Option: B
Explanation:

During ventricular systole, the deoxygenated blood from the right ventricle enters the pulmonary trunk, which carries blood to lungs for oxygenation. Thus option B is the correct answer. 

Blood from the left ventricle is pumped to

  1. Lungs

  2. Left auricle

  3. Right ventricle

  4. All parts of the body


Correct Option: D
Explanation:

The left ventricle is the thickest of the heart's chambers and is responsible for pumping oxygenated blood to tissues all over the body. By contrast, the right ventricle solely pumps blood to the lungs.

So, the correct option is 'All parts of the body'.

.............. receives oxygenated blood from the lungs.

  1. Right auricle

  2. Right ventricle

  3. Left auricle

  4. Left ventricle


Correct Option: C
Explanation:

The left atrium or left auricle receives oxygenated blood from the lungs through four openings of pulmonary veins. Thus option C is the correct answer. 

Which of the following is covered by pericardium membrane?

  1. Heart

  2. Kidneys

  3. Small intestine

  4. Stomach


Correct Option: A
Explanation:

The serosal pericardium is a closed sac within the fibrous pericardium. It consists of two layers. The visceral layer, called the epicardium, covers the heart and great vessels and is reflected back onto the parietal layer, which lines the interior of the fibrous pericardium.

So, the correct option is 'Heart'.

The blood with no oxygen is received in the 

  1. Left atrium

  2. Left ventricle

  3. Right atrium

  4. Right ventricle


Correct Option: C
Explanation:
The heart is the pumping organ of the body. It consists of four chambers i.e., the right auricle, left auricle, right ventricle and left ventricle. The right auricle receives the deoxygenated blood from the body and pumps it to right ventricle which in turn pumps it to the pulmonary artery. Whereas left auricle receives blood from lungs and pumps it to left ventricle from where it is pumped to the whole body through the aorta. Thus, the correct answer is option C.

The separation of the atria and ventricle helps to 

  1. Prevent mixing of the blood

  2. Pump blood only to lower parts of the body

  3. Pump blood only to upper parts of the body

  4. Both A and C


Correct Option: A
Explanation:
In the humans, the heart is a four-chambered muscular organ situated in the thoracic cavity in between the lungs. The upper two relatively small chambers are called atria and two larger lower chambers called ventricles. A thin, muscular wall called the interatrial septum separates the right and the left atria. whereas a thick-walled, the inter-ventricular septum, separates the left and the right ventricles. The right side of the heart has oxygenated blood and the left side has deoxygenated blood. Hence, the separation of the atria and ventricle helps to prevent mixing of the oxygenated and deoxygenated blood.
So, the correct answer is 'Prevent mixing of the blood'.

In aquatic mammals

  1. Heart will be small

  2. Heart will be large

  3. Lungs will be small

  4. Lungs will be large.


Correct Option: B

Papillary muscles occur in

  1. Ventricles

  2. Auricles

  3. Atrioventricular valves

  4. Pulmonary valves.


Correct Option: A

Ridges present in the ventricles are

  1. Columnae/Trabeculae carneae

  2. Papillary muscles

  3. Chordae tendineae

  4. Musculi pectinati.


Correct Option: A

Chordae tendineae are found in

  1. Atria of heart

  2. Ventricles of heart

  3. Joints of legs

  4. Ventricles of brain

  5. Joints of hands.


Correct Option: B

In order for the blood to flow from right ventricle to left ventricle in mammalian heart, it must flow through

  1. Right ventricle, pulmonary arteries, lungs, pulmonary veins, left atrium

  2. Right ventricle, pulmonary veins, lungs, pulmonary arteries, left atrium

  3. Right ventricle, right atrium, lungs, pulmonary veins, left atrium

  4. Right ventricle, systemic aorta, lungs, pulmonary veins, left atrium.


Correct Option: A

Ventricular diastole takes place due to activity of

  1. Tissue

  2. Organ

  3. Organ system

  4. Cell organelle.


Correct Option: A

Iter (Aqueduct of Sylvius) is found between

  1. Third and fourth ventricles

  2. Two lateral ventricles

  3. Lateral ventricles and third ventricle

  4. Rhinocoel and lateral ventricles


Correct Option: A

Choose the correct answer from the alternatives given.
The heart sound dup is produced when:

  1. mitral valve is opened

  2. mitral valve is closed

  3. tricuspid valve is opened

  4. semilunar valve at the base of aorta gets closed


Correct Option: D
Explanation:

In a healthy individual, there are two normal heart sounds called lub and dub. Lub is the first heart sound. It is associated with the closure of the tricuspid and bicuspid valves at the beginning of systole. The second heart sound dub is associated with the closure of the semilunar valves at the beginning of diastole.

So, the correct option is 'semilunar valve at the base of aorta gets closed'.

Choose the correct answer from the alternatives given.
Blood enters the heart because muscles of:

  1. atria relax

  2. ventricles relax

  3. atria contract

  4. ventricles contract


Correct Option: A
Explanation:

Human blood passes from the inferior vena cava into the diastolic right atrium of the heart because of a pressure differential between the atrium and the vena cava. This negative pressure gradient is created by atrial diastole and pulls blood to the atrium which is then pumped to the ventricles by contraction.

So, the correct answer is atria relax.

Choose the correct answer from the alternatives given.
In normal heart action:

  1. right atrium and ventricle contract, followed by the contraction of the left atrium and ventricle

  2. two atria contract together, then the two ventricles contract together

  3. right atrium and left ventricle contract, followed by the contraction of the left atrium and right ventricle

  4. all four chambers of the heart contract and then relax simultaneously


Correct Option: B
Explanation:

Due to one complete cardiac cycle, the two atria contract during the first 0.1 seconds, followed by ventricular systole for 0.3 seconds and finally joint diastole for 0.4 seconds. 

So, the correct option is 'Two atria contract together, then the two ventricles contract together'.

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