Tag: zoology

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'.

Removal of the thymus gland in the adult has little effect, but when the thymus is removed in the newborn, T cells in the blood and lymphoid tissue are depleted and failure of the immune system causes a gradual, fatal wasting disease. 

T cells or T lymphocytes are a type of lymphocyte, that plays a central role in cell-mediated immunity. They are called as T-cells because they mature in the thymus gland.

The thymus gland is an organ in the upper chest cavity, that processes lymphocytes, a type of white blood cell, that fights infections in the body. 

The thymus is a specialized organ of the immune system. Within the thymus, T cells or T lymphocytes mature. At birth, it is about 5 cm in length, 4 cm in breadth, and about 6 mm in thickness. The organ enlarges during childhood and atrophies at puberty. The thymus is at its largest in children. The thymus reaches maximum weight (20 to 37 grams) by the time of puberty. As one ages, the thymus slowly shrinks, eventually degenerating into tiny islands of fatty tissue. By the age of 75 years, the thymus weighs only 6 grams.