Skeletal and Muscle System Archives

1. The tissue which is responsible for movement in our body is

The tissue which is responsible for movement in our body is

Connective tissue.

Muscular tissue.

Nervous tissue.

Epithelial tissue.

This question was previously asked in

UPSC CISF-AC-EXE – 2021

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Muscular tissue is a type of animal tissue that is specialized for contraction. This contraction ability allows for movement of the body or parts of the body, as well as the movement of substances within the body (e.g., blood in vessels, food in the digestive tract).

There are three main types of muscular tissue: skeletal muscle, smooth muscle, and cardiac muscle. Skeletal muscle is responsible for voluntary movements of the limbs and body. Smooth muscle is found in the walls of internal organs and blood vessels, responsible for involuntary movements. Cardiac muscle is found in the heart and is responsible for pumping blood. All are specialized for contraction to produce movement.

Connective tissue provides support and structure. Nervous tissue transmits electrical signals for communication and control. Epithelial tissue covers surfaces and lines cavities, providing protection, secretion, and absorption. While these tissues interact with muscular tissue, the primary responsibility for generating movement lies with muscular tissue.

2. Consider the following minerals : 1. Calcium 2. Iron 3. Sodium Wh

Consider the following minerals :

1. Calcium
2. Iron
3. Sodium

Which of the minerals given above is/are required by human body for the contraction of muscles?

1 only

2 and 3 only

1 and 3 only

1, 2 and 3

This question was previously asked in

UPSC IAS – 2013

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Calcium and Sodium are minerals required by the human body for the contraction of muscles.

– **Calcium:** Calcium ions (Ca²⁺) are essential for initiating muscle contraction. In skeletal muscle, the release of calcium from the sarcoplasmic reticulum triggers the binding of myosin to actin filaments, leading to the sliding filament mechanism of contraction.
– **Sodium:** Sodium ions (Na⁺) play a critical role in the electrical signaling that initiates muscle contraction. An action potential, involving the influx of sodium ions across the muscle cell membrane, causes depolarization, which in turn leads to the release of calcium ions. Potassium ions (K⁺) are also crucial for repolarization and maintaining the membrane potential.
– **Iron:** Iron is vital for overall muscle function, primarily because it is a component of myoglobin, which stores oxygen in muscle cells, and enzymes involved in energy metabolism. However, it is not directly involved in the biochemical process of muscle fiber contraction itself in the same way calcium and sodium are.

Muscle contraction is a complex physiological process involving nerve impulses, changes in membrane potential, release of neurotransmitters, and the interaction of contractile proteins (actin and myosin) mediated by calcium ions. Electrolytes like sodium, potassium, calcium, and magnesium are all important for proper muscle and nerve function.

3. Which one of the following statements regarding muscle contraction and

Which one of the following statements regarding muscle contraction and relaxation is correct?

It involves movement of Zn++ ion.

It involves Ca++ ion of blood.

It involves release of Ca++ from sarcoplasmic reticulum (SR) and pumping Ca++ back in SR.

It involves exchange of Na and K.

This question was previously asked in

UPSC CAPF – 2018

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Muscle contraction is initiated by a signal (usually from a motor neuron) that leads to a sequence of events culminating in the sliding of actin and myosin filaments. A critical step in this process is the increase in the concentration of calcium ions (Ca++) in the sarcoplasm (the cytoplasm of a muscle cell). This Ca++ is primarily stored in the sarcoplasmic reticulum (SR), a specialized endoplasmic reticulum in muscle cells. Upon receiving the signal, Ca++ is released from the SR into the sarcoplasm. These released Ca++ ions bind to regulatory proteins on the actin filaments, allowing myosin heads to bind and cause contraction. Muscle relaxation occurs when the signal stops. Ca++ ions are then actively transported back into the SR by Ca++ pumps (SERCA pumps) located on the SR membrane. The reduction in sarcoplasmic Ca++ concentration causes the regulatory proteins to block myosin binding sites again, leading to muscle relaxation. Therefore, the release of Ca++ from the SR and its subsequent pumping back into the SR are central events in muscle contraction and relaxation.

Muscle contraction and relaxation are directly regulated by the concentration of Ca++ ions in the sarcoplasm, which is controlled by the release and re-uptake of Ca++ by the sarcoplasmic reticulum.

While other ions like Na+ and K+ are crucial for the electrical signaling (action potential) that triggers muscle contraction, and Zn++ is involved in various metabolic processes, the direct mechanism governing the binding and unbinding of myosin to actin, which constitutes the contraction/relaxation cycle, is primarily regulated by the availability of intracellular Ca++.

4. Which one among the following tissues help to connect two bones ?

Which one among the following tissues help to connect two bones ?

Tendons

Ligaments

Areolar tissue

Cartilage

This question was previously asked in

UPSC NDA-2 – 2024

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Ligaments are the type of connective tissue that helps to connect two bones together.

Ligaments are strong, fibrous bands that stabilize joints by holding bones in place.

Tendons connect muscles to bones. Areolar tissue is a loose connective tissue that fills spaces and supports organs. Cartilage is a specialized connective tissue providing cushioning and support, found in joints but not primarily connecting bones to each other across a joint; that’s the role of ligaments.

5. Tendons through which muscles are connected to bones are tightly compa

Tendons through which muscles are connected to bones are tightly compacted bundles of which one of the following long fibrous protein ?

Fibrin

Collagen

Elastin

Cellulose

This question was previously asked in

UPSC NDA-2 – 2017

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The correct answer is B) Collagen.

Tendons are tough bands of fibrous connective tissue that connect muscles to bones. They are primarily composed of tightly compacted bundles of collagen fibers.

Collagen is the most abundant protein in the human body and a key structural component of connective tissues, including tendons, ligaments, cartilage, bone, and skin. Elastin is another fibrous protein found in elastic tissues like blood vessels and skin, allowing them to stretch and recoil. Fibrin is a protein involved in blood clotting. Cellulose is a complex carbohydrate that forms the cell walls of plants.

6. Muscle fatigue is due to the accumulation of:

Muscle fatigue is due to the accumulation of:

Cholesterol

Lactic acid

Lipoic acid

Triglycerides

This question was previously asked in

UPSC NDA-2 – 2015

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Muscle fatigue during strenuous exercise is primarily associated with the accumulation of lactic acid.

When muscles undergo intense activity with insufficient oxygen supply (anaerobic respiration), glucose is broken down into pyruvate, which is then converted into lactic acid. The build-up of lactic acid in muscle tissue lowers pH and interferes with muscle contraction mechanisms, leading to a burning sensation and fatigue.

While other factors like depletion of energy stores (ATP, glycogen), ion imbalances, and central nervous system fatigue also contribute to overall fatigue, lactic acid accumulation is a significant factor in muscle fatigue during anaerobic work. Cholesterol and triglycerides are types of fats, and lipoic acid is an antioxidant coenzyme; none of these are directly responsible for the acute fatigue caused by intense muscle exertion.

7. Which one of the following types of tissues will have contractile prot

Which one of the following types of tissues will have contractile proteins ?

Nervous tissue

Muscle tissue

Bone tissue

Blood tissue

This question was previously asked in

UPSC NDA-1 – 2018

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The correct answer is (B) Muscle tissue. Muscle tissue is specialized for contraction and contains proteins like actin and myosin, which are referred to as contractile proteins. These proteins interact to generate force and movement.

Contractile proteins (actin and myosin) are the fundamental components responsible for the ability of muscle tissue to contract and produce movement.

Nervous tissue transmits electrical signals. Bone tissue provides structural support and protection. Blood tissue is a connective tissue involved in transport. None of these tissues are primarily characterized by the presence and function of contractile proteins to the extent of muscle tissue.

8. Tendons connect:

Tendons connect:

Bone to bone

Bone to cartilage

Muscle to bone

Cartilage to fat

This question was previously asked in

UPSC Geoscientist – 2021

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Tendons are strong, fibrous connective tissues that primarily serve to connect muscles to bones. This connection allows muscles to exert force on bones, enabling movement.

Tendons transmit force from muscles to bones.

Ligaments are another type of fibrous connective tissue, but they connect bone to bone. Cartilage is a flexible connective tissue found in various parts of the body, such as joints, ears, and nose.

9. Which one of the following body parts/organs of the human body does no

Which one of the following body parts/organs of the human body does not have smooth muscles ?

Ureters

Iris of eye

Bronchi of lungs

Biceps

This question was previously asked in

UPSC CDS-2 – 2019

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Smooth muscles are involuntary muscles found in the walls of internal organs and structures like the digestive tract, blood vessels, urinary tract, respiratory tract, uterus, and the iris of the eye. Their contractions are not under conscious control. Biceps brachii is a skeletal muscle located in the upper arm. Skeletal muscles are voluntary muscles that are attached to bones and are responsible for movement of the skeleton; they are characterized by their striated appearance under a microscope.

Smooth muscles are involuntary and found in internal organs; skeletal muscles are voluntary and attached to bones. Biceps are skeletal muscles.

Ureters are tubes that carry urine from the kidneys to the bladder; their walls contain smooth muscle for peristalsis. The iris controls the size of the pupil using smooth muscles (sphincter and dilator). Bronchi are airways in the lungs, and their walls contain smooth muscle that can constrict or relax.

10. A sprinter feels cramps and pain in the thigh muscles after a run. Thi

A sprinter feels cramps and pain in the thigh muscles after a run. This is due to accumulation of

lactic acid

CO₂

pyruvic acid

ethanol

This question was previously asked in

UPSC CDS-1 – 2023

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Muscle cramps and pain after intense exercise like sprinting are primarily caused by the accumulation of lactic acid.

During strenuous exercise when oxygen supply to muscle cells is limited, muscles switch to anaerobic respiration. This process breaks down glucose to produce energy (ATP) and lactic acid as a byproduct. The buildup of lactic acid lowers the pH in muscle cells, contributing to fatigue, pain, and muscle cramps.

Under sufficient oxygen conditions, muscles perform aerobic respiration, breaking down glucose completely to produce much more ATP, carbon dioxide, and water. Pyruvic acid is an intermediate product in both aerobic and anaerobic respiration. Ethanol is produced during anaerobic respiration in yeast and some plant tissues, but not typically in human muscles.