Railway Science (Biology – Skeleton System)

Muscular system - It is a system that includes muscle cells and muscle tissues. Nervous system - It is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body. Skeletal system - The framework of the body, consisting of bones and other connective tissues, which protects and supports the body tissues and internal organs.

Anaerobic respiration takes place in muscles to fulfill the demand for energy during exercises. Leg cramps occur during heavy lifting because lactic acid builds up in the muscles. Anaerobic respiration in muscle cells produces lactic acid as a byproduct.
During anaerobic respiration, glucose is partially broken down into lactic acid. Pyruvate - It is acid produced by glycolysis in the cytoplasm, the process in which the body breaks down sugar (glucose).

Striated Muscles: Cells are cylindrical and long, multinucleated, Voluntary action, Muscles remain attached to bones assisting in movement. Example - Muscles in limbs, neck, etc. Smooth Muscles: Elastic, not striated, spindle-shaped and contain a single central nucleus, arranged together in sheets. Example - Muscles of the iris of the eye, alimentary canal, oesophagus, uterus.

Muscle Cramp - Sudden, unexpected tightening of one or more muscles. During heavy exercise high energy demand is required but the supply of oxygen produced is limited. Anaerobic respiration takes place in the muscle cells to fulfill the demand for energy.
This anaerobic breakdown of glucose leads to the formation of lactic acid in muscles and the accumulation of lactic acid in muscles leads to muscle cramps.

Voluntary muscles (skeletal muscles) are muscles that are under conscious control. Allow us to move our body voluntarily, such as lifting weights, running, and jumping.
Attached to the bones of the skeleton and work in pairs, with one muscle contracting while the other relaxes to produce movement.
Made up of long, cylindrical cells called muscle fibers that contain many nuclei. Examples: Pectoral muscles, hamstrings, biceps, triceps, quadriceps, abdominals.

It is a connective tissue found in between skin and muscles, around blood vessels, nerves, and the bone marrow. It fills the space inside the organ, supporting the internal organ.
It is loaded with collagen fibres, making it strong and hard. Tendon is a connective tissue, which attaches skeletal muscles to bones.
Ligaments is a connective tissue, which attach one bone to another. Cartilage is a type of connective tissue that provides structural support and protection for the body's joints.

Muscle cramps- They are sudden, involuntary contractions in one or more of the muscles. Reason for muscle cramps - Dehydration, Low levels of electrolytes, Not enough blood circulation in muscles, Pregnancy, etc. Treatments for muscle crampsStretching or gently massaging the muscle, Applying heat when the muscle is tight and ice when the muscle is sore, and getting more fluids if dehydrated.

Adipose tissue:- It plays an important role as an energy reservoir, a modulator of energy homeostasis, and an endocrine organ.
Genetic predisposition, overeating and physical inactivity influence the expansion of adipose tissues.
Epithelial tissue forms the lining of respiratory, digestive, reproductive and excretory tracts. They perform various functions such as absorption, protection, sensation and secretion.
Areolar tissue provides nutrition to the cells and also acts as a cushion to protect the organs from various external forces.
Connective tissue supports, protects, and gives structure to other tissues and organs in the body.

Cuboidal epithelium (with cube-shaped cells). It protects the organ from mechanical and chemical stress. The covering or protective tissues in the animal body are epithelial tissues. Epithelium covers most organs and cavities within the body.
Glandular epithelium - It is an epithelial tissue involved in the production and release of different secretory products. Examples - Sweat, Saliva, Mucus etc. Columnar epithelium - Covers the intestinal tract from the end of the esophagus to the beginning of the rectum.

Bones - Adult - 206, infants - 300. Types of Bone cell - Osteoblasts (development and remodeling of the skeleton), Osteocytes (control the activity of osteoblasts and osteoclasts), Osteoclasts (produce acids and digestive enzymes to break down the minerals and proteins in bone) and bone lining cells (regulate the passage of calcium into and out of the bone).