Human Sensory and Locomotor Systems: Functions & Health

Touch

The skin is the largest organ of our body, composed of two layers:

• Epidermis: The outer layer is formed by epithelial tissue. The outer cells are dead and continuously shed as flakes and dandruff.
• Dermis: The inner layer, formed by connective tissue, provides elasticity to the skin. The dermis contains numerous blood vessels and tactile receptors.

Smell

The inside of the nostrils is lined by a mucosa called the pituitary gland. Two regions can be distinguished:

• Red pituitary: Occupies the lower part, has several blood vessels that warm the incoming air.
• Yellow pituitary: Occupies the upper part, contains numerous olfactory receptors.

Taste

At the top of the tongue are numerous projections called taste papillae. These contain sensitive cells (chemoreceptors) called taste buds, that detect four basic tastes: sweet, salty, sour and bitter. The rest of the flavors come from different combinations.

Locomotor System

It is responsible for carrying out the motor responses produced by the nervous system.

Skeletal System

This consists of the skeleton, an integrated mobile internal frame of bones, joints, and ligaments, allowing the union of bones. Its functions include supporting the body's weight and protecting organs from blows.

Muscular System

It is the active part of the locomotor system. It is formed by muscles and tendons. Its tasks include producing movements to carry out vital functions, maintaining posture, and enabling facial expressions.

Bones

Bones are living organs that grow and nourish themselves. They are composed of calcium, phosphorus, and a substance called collagen.

Joints

Joints are structures connecting the bones, preventing their separation.

• Immobile: Do not allow movement of the bones, such as the joints of the skull.
• Semi-mobile: Join bones strongly but allow a small movement, like the joints of the vertebrae.
• Mobile: Allow a variety of movements between the bones, such as the elbow, shoulder, or knee.

Muscles

Muscles are formed by elongated cells called muscle fibers. These organs can contract or relax, enabling a wide range of movements.

• Smooth muscles: Slow and involuntary contractions, composed of smooth muscle fibers.
• Cardiac muscles: Rapid, involuntary, striated muscle fibers.
• Skeletal muscles: Rapid and voluntary, striated muscle fibers.

Diseases

• Fracture: Broken bone.
• Sprains: Injury related to any type of inflammation.
• Dislocations: Bones move out of position.
• Contractures: Involuntary muscle contractions.