Tag: evolutionary changes in heart

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Multiple choice evolutionary changes in heart transportation - the circulatory system

Single heart circuit occurs in

  1. Fishes

  2. Frog

  3. Reptiles

  4. Man
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All vertebrates possess a muscular chambered heart. Fishes have a 2-chambered heart with an atrium and a ventricle. 

Amphibians and the reptiles (except crocodiles) have a 3-chambered heart with two atria and a single ventricle, whereas crocodiles, birds and mammals possess a 4-chambered heart with two atria and two ventricles. 
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 (single circulation).

Multiple choice evolutionary changes in heart transportation - the circulatory system

Right atrium of rabbit receives

  1. Two anterior vena cava

  2. Two posterior vena cava

  3. One anterior and one posterior vena cava

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Right atrium of the mammalian heart receives deoxygenated blood from anterior (superior) vena cava and posterior (inferior) vena cava. Thus, the right atrium has only deoxygenated blood. After systole, the deoxygenated blood from the right atrium goes to the lung for purification.

Multiple choice evolutionary changes in heart transportation - the circulatory system

Alary muscles in cockroach are associated or connected with

  1. Trachea

  2. Heart

  3. Legs

  4. Alimentary canal
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alary muscles in cockroach are associated or connected with Heart. These muscles are attached to both dorsal and tergum diaphragm. They are triangular in shape where in the pointed end is attached to the tergum and other end is attached to dorsal diaphragm. The alary muscles are responsible for the circulation of blood. Hence option B is correct.

Multiple choice evolutionary changes in heart transportation - the circulatory system

Heart of fishes is

  1. Two chambered

  2. Venous heart

  3. Both of the above

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

All vertebrates possess a muscular chambered heart. Fishes have a 2-chambered heart with an atrium and a ventricle. 

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 (single circulation). Because the heart pumps deoxygenated blood in fishes, it is called as a venous heart.

Multiple choice evolutionary changes in heart transportation - the circulatory system

Heart of cockroach is

  1. Four chambered

  2. Ventral to gut

  3. Longitudinal and beaded

  4. Three chambered
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cockroach has a 13 chambered longitudinal, thick, muscular and beaded heart. Each chamber receives oxygenated blood through slit like openings called ostia. 

Multiple choice evolutionary changes in heart transportation - the circulatory system

Heart of frog differs from that of rabbit by presence of

  1. Sinus venosus

  2. Four chambers

  3. Mitral valve

  4. Two aortae
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sinus venosus and conus arteriosus are not found in rabbit but they are present in the frog. In the rabbit, sinus venosus is formed in the embryo but later it becomes a part of the wall of the right auricle. So the impure (deoxygenated) blood collected by the precavals and postcavals directly comes into the right auricle. The pure blood brought by the pulmonary veins from the lungs directly come into left auricle.

Multiple choice evolutionary changes in heart transportation - the circulatory system

Single heart circuit occurs in

  1. Fish

  2. Frog

  3. Reptile

  4. Man
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

All vertebrates possess a muscular chambered heart. 

Fishes have a 2- chambered heart with an atrium and a ventricle. Amphibians and the reptiles (except crocodiles) have a 3- chambered heart, with two atria and a single ventricle, whereas crocodiles, birds and mammals possess a 4- chambered heart with two atria and two ventricles. 
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. As it regulates through single circuit, it is called as single circulation.

Multiple choice evolutionary changes in heart transportation - the circulatory system

The number of chambers in the heart of a frog is

  1. One

  2. Two

  3. Three

  4. Four
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The frog heart has 3 chambers two atria and a single ventricle. The atrium receives deoxygenated blood from the blood vessels (veins) that drain the various organs of the body. The left atrium receives oxygenated blood from the lungs and skin (which also serves as a gas exchange organ in most amphibians). 

Therefore, the correct answer is option C.

Multiple choice evolutionary changes in heart transportation - the circulatory system

In rabbit, oxygenated blood flows from

  1. Left auricle to left ventricle during auricular systole

  2. Right auricle to right ventricle during ventricular systole

  3. Right ventricle to aorta during ventricular systole

  4. Pulmonary vein to left auricle during auricular systole
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The left part of the mammalian heart contains only oxygenated blood. During auricular diastole, the oxygenated blood from the lungs come into left auricle. During auricular systole, the oxygenated blood comes into left ventricle.

Multiple choice evolutionary changes in heart transportation - the circulatory system

The heart of which animal is myogenic in nature?

  1. Cockroach

  2. Leech

  3. Elephant

  4. All of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The heart of an elephant is myogenic, as all the vertebrates have myogenic hearts. 

Myogenic contraction refers to a contraction initiated by the myocyte cell itself instead of an outside occurrence or stimulus, such as nerve innervation. 
For most invertebrates, heart contraction is initiated and regulated predominantly by external nerves; thus insect hearts are neurogenic. In contrast, vertebrates, tunicates, and some molluscs have myogenic hearts. The heartbeat is initiated and regulated by specialized groups of muscle cells.