Support and Movement System

Support and Movement System

• Humans and animals possess the ability to move
• Movement is crucial for obtaining food, escaping danger, and protecting habitat
• Support and movement systems allow bodily actions
• These systems provide structure and rigidity to the body
• The skeleton enables displacement and movement
• Movement happens due to the combined efforts of the skeleton and muscles
• The skeleton provides shape, protects internal organs, and supports the body
• Skeletal structure is made up of bones

Skeletal System

• The skeletal system provides support and movement in vertebrates
• It consists of bones, skeletal muscles, nerves, and joints
• The skeletal system forms the body's frame & provides attachment for muscles
• The system consists of bones, joints, and cartilage
• An adult human skeleton contains 206 bones
• Newborns approximately have 300 bones
• Joints are the connection points between bones and crucial for movement
• Muscles enable movement

Bone Classification by Shape

• Bones can be categorized into long, short, and flat

• Long Bones:

  • Elongated bones with thicker ends
  • Supports body movement
  • Includes the ulna, radius, metacarpals, femur, tibia, fibula, and phalanges

• Short Bones:

  • Bones where length and width dimensions are near equal
  • Includes the wrist and ankle bones

• Flat Bones:

  • Flat, plate-shaped bones
  • Includes skull bones, scapula, sternum, ribs, hip bone, and pelvic bone

Functions of the Skeleton

• Provides support and maintains posture
• Facilitates movement with the aid of muscles
• Provides surface area for muscle and organ attachment
• Stores minerals like phosphate, magnesium, potassium, and calcium
• Produces blood cells like red blood cells and white blood cells

Rib Cage

• Composed of spine, ribs, and sternum
• Protects the lungs and heart and forms the chest cavity
• The sternum is a flat bone in the middle of the chest where ribs and collarbones articulate
• Ribs form joints with the sternum and collarbones
• Ribs are present in 12 pairs with left and right sides
• Each shoulder girdle contains two bones: the scapula and clavicle

The Joint and Structure

• A joint facilitates the connection of two or more bones

Joint Types Based on Movement

• Joints are categorized by mobility: movable, semi-movable, and immovable

• Movable Joints:

  • Allows for a wide range of motion in various directions
  • Includes the shoulder, elbow, hip, knee, and ankle joints
  • A fluid similar to egg white reduces friction between bones

• Semi-Movable Joints:

  • Have limited movement capabilities due to cartilage pads between bones
  • Includes the vertebrae of the spine

• Immovable Joints:

  • Are fixed joints that do not allow any movement
  • Found in the skull and pelvic bones where bones are tightly connected

Muscle System in Humans

• Muscles are the tissues that enable movement

Three basic muscle types

• Striped (Skeletal) Muscle:

  • Connects to the skeletal system
  • Helps with voluntary movement
  • These are fast-acting but tire quickly
  • Examples include muscles of the arm, leg, neck

• Smooth Muscle:

  • Found in the walls of internal organs, and blood vessels
  • Contractions happen involuntarily and are slow and consistent
  • Consist of single-nucleated cells

• Cardiac Muscle:

  • It has a similar composition to skeletal muscle
  • Makes up the heart tissue
  • Contracts rhythmically and constantly
  • Consists of very strong cells

Muscle Function

• Muscles cover the skeleton, giving shape and enabling movement through contraction and relaxation
• In addition to movement, they help protect and support the body
• Enable people to use objects, communicate, and perform various functions such blinking and digestion
• Skeletal muscles connect to bones through tendons, composed of white and sturdy tissue
• Muscles usually function in pairs
• When one muscle contracts, the opposing muscle relaxes, this is known as antagonistic muscles
• Cardiac muscle works regularly like a motor, carrying out rhythmic contractions
• Cardiac muscles are strong and do not fatigue, but operate beyond own control
• Smooth muscle is present in the walls of organs; its contractions are involuntary, slow, and regular
• Smooth muscle cells have a single nucleus

Cartilage

• Cartilage is a type of flexible connective tissue
• Cartilage is in the auricle, part of our nose, as well as airways.
• Cartilage also prevents wear and tear bones during body movement
• Bones form after hardening of cartilage tissue