All the components of the nodal tissue are autoexcitable. Why does the SA node act as the normal pacemakar?
- SA node has the lowest rate of depolarisation.
- SA node is the only component to generate the threshold potential.
- Only SA node can convey the action potential to the other components.
- SA node has the highest rate of depolarisation.
The Correct Option is D
Approach Solution - 1
Approach Solution -2
Ans: SA nodes can act as the normal pacemaker because it has the highest rate of depolarization. The change in the electrical potential across the cell membrane is called depolarization, which will eventually lead to generation of action potential. This action potential will cause the muscle to contract. Thus on depolarization heart muscles contract and therefore pumping of the blood. SA nodes have the highest depolarization rate because their cells have the ability to automaticity. This allows the cells to generate action potentials spontaneously. The SA nodes also have ion channels thus help the cells to reach the threshold much faster.
Learn with videos:
Top Questions on Circulatory Pathways
- Which of the following is the primary function of red blood cells?
- MHT CET - 2025
- Biology
- Circulatory Pathways
- What is the function of the human heart's left ventricle?
- MHT CET - 2025
- Biology
- Circulatory Pathways
- Product of Cyclic Pathway
- BCECE Nursing - 2024
- Biology
- Circulatory Pathways
- Following are the stages of pathway for conduction of an action potential through the heart
A. AV bundle
B. Purkinje fibres
C. AV node
D. Bundle branches
E. SA node
Choose the correct sequence of pathway from the options given below- NEET (UG) - 2024
- Biology
- Circulatory Pathways
- How do most arthropods circulate nutrients and gases throughout their bodies?
- MHT CET - 2024
- Biology
- Circulatory Pathways
Questions Asked in NEET exam
- A body weighs 48 N on the surface of the earth. The gravitational force experienced by the body due to the earth at a height equal to one-third the radius of the earth from its surface is:
- NEET (UG) - 2025
- Gravitational potential energy
A bob of heavy mass \(m\) is suspended by a light string of length \(l\). The bob is given a horizontal velocity \(v_0\) as shown in figure. If the string gets slack at some point P making an angle \( \theta \) from the horizontal, the ratio of the speed \(v\) of the bob at point P to its initial speed \(v_0\) is :
- NEET (UG) - 2025
- Pendulums
- An oxygen cylinder of volume 30 litre has 18.20 moles of oxygen. After some oxygen is withdrawn from the cylinder, its gauge pressure drops to 11 atmospheric pressure at temperature \(27^\circ\)C. The mass of the oxygen withdrawn from the cylinder is nearly equal to: [Given, \(R = \frac{100}{12} \text{ J mol}^{-1} \text{K}^{-1}\), and molecular mass of \(O_2 = 32 \text{ g/mol}\), 1 atm pressure = \(1.01 \times 10^5 \text{ N/m}^2\)]
- NEET (UG) - 2025
- Ideal-gas equation and absolute temperature
- A uniform rod of mass 20 kg and length 5 m leans against a smooth vertical wall making an angle of \(60^\circ\) with it. The other end rests on a rough horizontal floor. The friction force that the floor exerts on the rod is (take \(g = 10\) m/s\(^2\)):
- NEET (UG) - 2025
- Common forces in mechanics
- A wire of resistance \(R\) is cut into 8 equal pieces. From these pieces, two equivalent resistances are made by adding four of these together in parallel. Then these two are added in series. The net effective resistance of the combination is:
- NEET (UG) - 2025
- Resistance
Concepts Used:
Circulatory Pathways
Virtually every cell, tissue, organ, and system in the body is impacted by the circulatory system.
- Digestive - Absorbs nutrients and water; delivers nutrients (except most lipids) to liver for processing by hepactic portal vein; provides nutrients essential for hematopoiesis and building hemoglobin.
- Endocrine - Delivers hormones: atrial natriuretic hormone (peptide) secreted by the heart atrial cells to help regulate blood volumes and pressures; epinephrine, ANH, angiotensin II, ADH, and thyroxine to help regulate blood pressure; estrogen to promote vascular health in women and men.
- Integumentary - Carries clotting factors, platelets, and white blood cells for homeostatis, fighting infection, and reparing damage; regulates temperature by controlling blood flow to the surface, where heat can be dissipated; provides some coloration of integument; acts as a blood reservoir.
- Muscular - Provides nutrients and oxygen for contraction; removes lactic acid and distributes heat generated by contraction; muscular pumps aid in venous return; exercise contributes to cardiovascular health and helps to prevent atherosclerosis.