Tag: skeleton and movements

The ligament is the connective tissue which attaches two or more bones together to form a joint. When the ligament breaks, the two bones cannot be held together and dislocate. Generally, when the person met with an accident and the ligament is broken, there are chances that the person will suffer from the dislocation of the bones. 

• Osteoporosis is defined as low bone mass and microarchitectural deterioration of the bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk.
• It may occur due to various reasons such as calcium deficiency, increase in osteoclastic or osteoblastic activity, age, estrogen deficiency in females etc.
• Hence bones become fragile (easily broken or damaged) due to osteoporosis.
• So,the correct answer is 'Osteoporosis'.

Myasthenia gravis is a disease caused due to the antibodies produced by an immune system that blocks or destroy the receptor sites for a neurotransmitter called acetylcholine. The enzyme esterase or acetylcholine esterase break the acetylcholine and deactivates the neurotransmitter to stop muscle activation. 

Symptoms of tetanus include
 a)Tetanus often begins with mild spasms in the jaw muscles known as lockjaw. The spasms can also affect the facial muscles and experience spasms and stiffness in various muscles, especially those in jaw, abdomen, chest, back, and neck.
b)Muscle cramps or spasms in your legs, fever, high blood pressure etc
Hypoparathyroidism is decreased function of the parathyroid glands with underproduction of parathyroid hormone. This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany (involuntary muscle contraction).
Hence parathyroid gland is associated with tetanus.
So, the correct answer is 'Parathyroid gland'.

• Autoimmune diseases are a group of disorders in which tissue injury is caused by humoral(autoantibodies)or cell-mediated(by autoreactive T cells) immune response to self-antigens.
  
• Myasthenia gravis is caused by an autoantibody against muscle antigen and acetylcholine receptor antigen.
  
• Myasthenia gravis is characterized by increased muscular weakness the make one fatigue. speaking, breathing and talking becomes tired some. Hence myasthenia gravis is an example of autoimmune disease.
  
• So, the correct answer is 'Autoimmune disease'.
  

• Muscular dystrophy is a group of inherited muscle diseases in which muscle fibers are unusually susceptible to damage.
  
• It is characterized by progressive skeletal muscle degeneration, defects in muscle proteins and the death of muscle cell and tissue.
• Hence progressive degeneration of skeletal muscle, mostly due to genetic disorder occurs in muscular dystrophy.
• So, the correct answer is 'Muscular dystrophy'.

Myosin is the primary motor protein in muscle fibers, forming the thick filaments that interact with actin to cause contraction. While actin is also a major constituent, myosin is the most abundant protein in the muscle fiber.

• The myofibril is composed of two types of filaments. They are thick filament(Myosin) and Thin filament(Actin).
  
• Increase in Ca++ level leads to the binding of calcium with a subunit of troponin i.e troponin-C on actin filaments and thereby remove the masking of active sites for myosin. Utilizing the energy from ATP hydrolysis, the myosin head now binds to the exposed active sites on actin to form a cross bridge.
  
• Each myosin (thick) filament is also a polymerized protein. Many monomeric proteins called Meromyosins constitute one thick filament. Each meromyosin has the globular head is an active ATPase enzyme and has binding sites for ATP and active sites for actin.
  
• Hence actin binding sites are located over meromyosin'.
• So, the correct answer is 'Meromyosin'.

• Skeletal muscle fiber is made up of two types of filaments. They are thick filament and thin filament.
  
• Thick filament is made up of a protein called Myosin. Actin filaments are thinner as compared to the myosin filaments, hence are commonly called thin and thick filaments respectively
  
• Each myosin (thick filament) is made up of Many monomeric proteins called Meromyosins.
• Hence the thick myofilament from the given contractile proteins is myosin.
• So.the correct answer is 'Myosin'.

• Each myofibril consists of a series of contractile units (sarcomeres) connected at a protein border (the Z line).
•  Thin filaments(actin) of adjacent sarcomeres are present in the Z line between the thin filaments are thick filaments(myosin). 
• The protein tropomyosin winds around the thin filaments and covers the myosin binding sites. Hence, In skeleton muscle, Z-line is connected to actin.