axial skeleton

Examples of axial skeleton in the following topics:

• The Axial Skeleton

• The Axial Skeleton

• Overview of the Axial Skeleton

  • The axial skeleton consists of the 80 bones along the central axis of the human body.
  • The axial skeleton consists of the 80 bones along the central axis of the human body.
  • The axial skeleton and the appendicular skeleton together form the complete skeleton.
  • The word "axial" is taken from the word "axis" and refers to the fact that the bones are located close to or along the central axis of the body.
  • The human rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic cavity and supports the pectoral girdle, forming a core portion of the human skeleton.

• Divisions of the Skeletal System: Axial and Appendicular

  • The skeletal system is divided into two distinct divisions: the axial skeleton and the appendicular system.
  • It is a complex structure with two distinct divisions: the axial and the appendicular skeletons.
  • The axial skeleton consists of the 80 bones along the central axis of the human body.
  • Functionally, it is involved in locomotion (lower limbs and pelvic girdle) of the axial skeleton and manipulation of objects in the environment (upper limbs and pectoral girdle) .
  • Differentiate the purpose and the number of bones of the axial and appendicular skeletons

• Human Axial Skeleton

  • The axial skeleton forms the central axis of the human body and consists of the skull, vertebral column, and thoracic cage.
  • The axial skeleton forms the central axis of the human body and includes the bones of the skull, the ossicles of the middle ear, the hyoid bone of the throat, the vertebral column, and the thoracic cage (ribcage) .
  • The function of the axial skeleton is to provide support and protection for the brain, spinal cord, and organs in the ventral body cavity.
  • The thoracic cage, also known as the ribcage, is the skeleton of the chest.
  • The axial skeleton consists of the bones of the skull, ossicles of the middle ear, hyoid bone, vertebral column, and rib cage.

• Overview of the Appendicular Skeleton

  • In the human body, the appendicular skeleton is unfused (unlike the axial skeleton), which allows for a much greater range of motion.
  • The appendicular skeleton is composed of 126 bones.
  • Note that these areas may include other bones that are not a part of the appendicular skeleton; they are instead a part of the axial skeleton.
  • The femur, tibia, patella, and fibula are all a part of the appendicular skeleton.
  • The appendicular skeleton is composed of the six major regions shown here.

• Human Appendicular Skeleton

  • The appendicular skeleton supports the attachment and functions of the upper and lower limbs of the human body.
  • The human appendicular skeleton is composed of the bones of the upper limbs (which function to grasp and manipulate objects) and the lower limbs (which permit locomotion).
  • The pectoral girdle bones, providing the points of attachment of the upper limbs to the axial skeleton, consists of the clavicle (or collarbone) in the anterior, as well as the scapula (or shoulder blades) in the posterior .
  • The pelvic girdle attaches to the lower limbs of the axial skeleton and is responsible for bearing the weight of the body and for locomotion.
  • It is securely attached to the axial skeleton by strong ligaments.

• Types of Skeletal Systems

  • There are three different skeleton designs that provide organisms these functions: hydrostatic skeleton, exoskeleton, and endoskeleton.
  • Although a hydrostatic skeleton is well-suited to invertebrate organisms such as earthworms and some aquatic organisms, it is not an efficient skeleton for terrestrial animals.
  • The skeletal system in vertebrates is divided into the axial skeleton (which consists of the skull, vertebral column, and rib cage), and the appendicular skeleton (which consists of the shoulders, limb bones, the pectoral girdle, and the pelvic girdle).
  • The skeleton of the red-knobbed sea star (Protoreaster linckii) is an example of a hydrostatic skeleton.
  • The skeletons of humans and horses are examples of endoskeletons.

• Steroids

  • Steroids may be recognized by their tetracyclic skeleton, consisting of three fused six-membered and one five-membered ring, as shown in the diagram below.
  • Substituent groups at different sites on the tetracyclic skeleton will have axial or equatorial orientations that are fixed because of the rigid structure of the trans-fused rings.
  • Thus an equatorial hydroxyl group is esterified more rapidly than its axial isomer.
  • Each chair is fused to the other by equatorial bonds, leaving the angular hydrogens (Ha) axial to both rings.
  • In the conformer on the right, the carbon bond to C-1 is equatorial and the bond to C-6 is axial.

• The Appendicular Skeleton