Biology · General Awareness

Human Circulatory System

818 Questions

The human circulatory system explores the network of blood vessels, heart valves, and structural pathways. Test items often target blood flow sequences and specific vascular functions. Mastering these details is vital for biology preparation.

Heart valves and chambersBlood vessels and venulesArteries of the bodyBlood supply to organsCentral nervous system supply

Human Circulatory System Questions

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Find the correct explanations about blood not clotting inside the vessels
1. Speedy flow prevents accumulation of fibrin threads if formed
2. Absence of anticoagulant heparin having antithrombin activity
3. Smoothness of endothelial lining preventing rupturing of platelets and formation of thromboplastin
4. Presence of a layer of negetively charged protein over the inner surface of endothelium that attracts clotting factors.

  1. 1, 2, 3 correct

  2. 1, 2 correct

  3. 2, 4 correct

  4. 1, 3 correct.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Blood does not clot inside vessels due to the smooth endothelial lining (preventing platelet rupture) and the rapid flow of blood (preventing the accumulation of clotting factors). Heparin is present as a natural anticoagulant, and the endothelium is negatively charged to repel platelets.

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Identify the correct sequence of blood coagulation (a) Activation of prothrombin (b) Formation of prothrombin activator (c) Formation of blood clot (d) Conversion of fibrinogen to fibrin

  1. b - d - a - c

  2. b - a - d - c

  3. a - d - c - b

  4. a - b - c - d
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Blood coagulation occurs in the following sequence:
  • Whenever there is rupture of blood vessels or damage is caused to blood, a complex of substances called prothrombin activator complex is formed. 
  • The activators convert prothrombin into thrombin.
  • Thrombin acts as an enzyme and converts fibrinogen into fibrin threads.
  • Fibrin threads accumulate and clump to form blood clot at the wound site.
So, the correct answer is 'b- a- d- c'.
Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Conversion of fibrinogen to fibrin is catalysed by

  1. Thrombin

  2. Prothrombin

  3. Thromboplastin

  4. All of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Thrombin catalyzes the conversion of fibrinogen (factor I)—a soluble plasma protein into long, sticky threads of insoluble fibrin . The fibrin threads form a mesh that traps platelets, blood cells, and plasma.The fibrin mesh work begins to contract in a short period of time and prevents blood loss. 
So, the correct answer is 'Thrombin'
Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Which of these are necessary for initiation of blood clotting process?

  1. Prothrombinase and thrombin
  2. Tissue factor hageman factor and $Ca^{2+}$
  3. Prothrobinase and $K^{2+}$
  4. Prothrobinase , tissue factor and $Ca^{2+}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

There are two processes that can initiate clotting

  1. A very rapid process the so-called extrinsic pathway 
  2. A slower but larger intrinsic pathway
In the extrinsic pathway- Damaged cells display a surface protein called tissue factor
In the intrinsic pathway- Factor 12 (XII) (also called the Hageman factor) circulates in the blood.
Calcium ions are required for the promotion or acceleration of blood clotting pathways
So correct option is B, Tissue factor hageman factor and $Ca^{2+}$.

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

The blood does not clot inside the body because of

  1. Oxygenation of blood

  2. Movement of blood

  3. Heparin in blood

  4. Absence of fibrinogen in blood
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
A blood clot is actually the thickened mass formed by the blood platelets and stops the blood profusely out of any cuts or wounds. However, in general and in healthy condition blood does not form clots inside the body due to the presence of heparin an anticoagulant that is secreted by the basophils and mast  cells of the blood. Since, this is released into the blood vessels it prevents the formation of clots in them
So, the correct answer is 'Heparin in blood'
Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Which option is correct for the formation of intrinsic factor-X activator complex for blood coagulation?

  1. Activated Christmas factor + AHG + phospholipid + $Ca^{+2}$
  2. Inactivated Christmas factor + AHG + phospholipid +$Ca^{+2}$
  3. Convertin + AHG + $Ca^{+2}$+ FSF

  4. Phospholipid - protein complex + Proconvertin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Hageman factor XII is activated when it comes in contact with a damaged blood vessel. The activated Hageman factor activates the factor XI. The activated factor XI acts on Chrishmas factor IX to form activated IXa. Factor IXa combines with AHG VIII phospholipid and calcium ions to form a complex called intrinsic factor X activator complex. Thus the correct answer is option A.

Multiple choice biology soldiers of defense blood clotting and healing of wounds coagulation of blood blood clotting

Fill in the blanks with suitable words given below:
The liquid part of coagulated blood is known as _________

  1. Serum

  2. Fibrinogen

  3. Hemoglobin

  4. Pulmonary

  5. Sphygmomanometer

  6. Ventricles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The liquid part of coagulated blood is known as serum. It is the liquid portion of blood clot . It includes all proteins not used in clotting of blood and all the electrolytes, hormones, antibodies, antigens etc..

Hence, the correct answer is 'Serum' .

Multiple choice evs communicable diseases infectious diseases - transmission and prevention infectious diseases and how to prevent them pathogen and their mode of transmission

After cobra bite, venom affects the

  1. Brain

  2. Blood circulation

  3. Lungs

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

Cobras belong to the elapids sub-group of snakes and there

are over 270 species of cobras. Cobra's venom

contains postsynaptic neurotoxins that spread rapidly into the victim's

bloodstream and affects the lungs causing respiratory failure and eventually, death.

Multiple choice bio-chemistry digestion liver functions of the liver secretory organs

Which of the following is not a blood vessel entering the liver?

  1. Hepatic artery

  2. Hepatic portal vein

  3. Hepatic vein

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

The hepatic artery and hepatic portal vein carry blood into the liver. The hepatic vein carries blood away from the liver toward the inferior vena cava.

Multiple choice bio-chemistry digestion liver functions of the liver secretory organs

Sinusoids are characterised by

  1. Irregular lumen

  2. Absence of endothelium

  3. Mixing of blood and lymph

  4. Both B and C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sinusoids are characterized by a form of terminal blood channel consisting of a large, irregular anastomosing vessel having a lining of reticulo-endothelium and found in the liver, heart, spleen, pancreas, and the adrenal, parathyroid, carotid, and hemolymph glands.

So, the correct option is 'Irregular lumen'.

Multiple choice biology digestion and absorption liver functions of the liver secretory organs

Angiotensinogen is a protein produced by

  1. Macula densa cells

  2. Liver cells

  3. Juxtaglomerular cells

  4. Endothelial cells
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Angiotensinogen is a plasma protein produced and secreted by liver cells. It is a sole precursor of all angiotensin peptide. Juxtaglomerular cells secrete renin which acts on angiotensinogen to release angiotensin I and then it is converted to angiotensin II by the action of enzyme angiotensin-converting enzymes.
So, the correct answer is 'Liver cells'.