Skeletal system | functions and types

 

Skeletal system | functions and types

Skeletal system

 This system includes skeleton and articulations. It is a central framework of our body. Skeleton of human include more than 200 bones, cartilages and ligaments. Bone is a rigid connective tissue while cartilage is soft connective tissue. Ligaments are tough elastic tissue around the joints. They connect bone to bone and give joints support and also limit their movement. Ligaments are present around the knees, ankles, elbows, shoulders, and other joints. Stretching or tearing ligaments can make joints unstable.

Functions of skeletal system

(1) SUPPORT: it provides support to the body.

(2) PROTECTION: it provides protection and a place for muscle attachment. It provides support and protection for soft tissues and organs

(3) MOVEMENT: It help in movement.

(4): STORE MINERALS: It is a reservoir of minerals (calcium and phosphorus). When body is in need of these minerals, they are released.

(5): PRODUCTION OF BLOOD VESSELS: It produces all blood cells.

(6): POSTURE: skeleton provide posture to body.

Types of skeletons

1: Hydrostatic Skeleton(soft)

It has fluid filled core (water or blood). In hydrostatic skeleton, body wall is tension resistant. Muscles are longitudinal or circular.

Examples: Sea anemone and earthworm

2. Rigid skeleton

It contains rigid elements. It provides attachment points for pairs of opposing muscles. It provides protection & support.

Exoskeleton

It is found in mollusks & arthropods and some other invertebrates. External covering is rigid. It often restricts animal growth involves molting. Sometimes it has specialized materials for added strength.

Arthropods have chitin secreted by epidermis.

Gastropods have CaCO3 deposits.

Endoskeleton

It is found in echinoderms, chordates, and some cnidarians.  In ostracoderms, bone, dentine, cartilage, and enamel form endoskeletons.

In invertebrates, CaCO3 crystals in collagen fibers.

In sponges, mineral spicules and fibers of spongin (no muscles attached).

In echinoderms, calcareous plates called ossicles.

In vertebrates, most familiar endoskeletons (Bone and Cartilage).