SKELETAL-SYSTEM-OF-FROGS

Skeletal System of a Frog

Overview

  • Group 4: Skeletal System of a Frog

Functions of Frog Skeleton

  • Support: Maintains the structure and form of the frog.

  • Protection: Shields vital organs from injury.

  • Movement: Facilitates locomotion through limbs.

  • Storage: Stores minerals and fats.

  • Blood Cell Formation: Produces blood cells in bone marrow.

  • Interesting Fact: A frog’s skeleton contains about 57 bones, compared to 206 in the average adult human.

Types of Skeletons

  • Endoskeleton: Comprised of bone and/or cartilage along with accessory tissues (e.g., tendons, ligaments).

  • Exoskeleton: The hardened portion covering the body, such as scales, feathers, fur, claws, and nails.

Bone Development

Types of Bone

  • Cartilage Bone: Develops first as cartilage through chondrification, later ossifying into bone.

  • Membrane Bone: Forms directly into bone without a cartilage stage.

Bone Location and Classification

Axial Skeleton

  • Comprises:

    • Bones of the head (skull)

    • Bones of the trunk, including vertebral column and thorax

Appendicular Skeleton

  • Comprises:

    • Bones of paired limbs

    • Pectoral (shoulder) and pelvic girdles

Axial Skeleton of Frog

Skull

  • Major bones include:

    • Maxilla: Upper jawbone that bears teeth.

    • Squamosal: Hammer-shaped bone at the skull's lateral end.

    • Fronto-Parietal: Paired bones at the rear end of the skull.

    • Nasal: Triangular paired bones covering the nasal capsules.

Other Axial Skeleton Structures

  • Prootics: Small paired bones near the ear region.

  • Exoccipitals: Large paired bones forming the rear skull, defining the foramen magnum for spinal cord passage.

  • Premaxillae: V-shaped bones at the extreme front of the maxillary arch, containing teeth.

Dorsal Axial Skeleton Structure

  • Further details include:

    • Maxillae: Tooth-bearing bones behind premaxilla.

    • Quadratojugal: Non-tooth-bearing bone fused with a triradiate bone.

    • Otic Capsules: Structures containing hearing and balance organs.

Ventral Axial Skeleton Structure

  • Columella (Stapes): Bone that transmits sound waves from the eardrum.

  • Pterygoids: Irregular bones forming attachments in the maxillary arch.

  • Quadrates: Short bones wedged between other cranial bones.

Vertebral Column

Structure

  • Total of 10 vertebrae in frogs.

  • Functions:

    • Supports trunk, protects spinal cord, aids in locomotion, supports head and viscera.

Vertebrae Types

  1. Atlas Vertebrae: First vertebra articulating with the skull.

  2. Typical Vertebrae (2-7): Supportive structure with specific features like neural arch and processes.

  3. Amphicoelous Vertabrae: Eighth vertebra, biconcave.

  4. Sacral Vertebrae: Ninth vertebra linked with pelvic structure.

  5. Urostyle: Last segment of the vertebral column, providing rigidity.

Additional Anatomical Features in Skeleton

Features of Sternum

  • Protects the heart and lungs with four parts:

    1. Episternum: Anterior, circular, cartilaginous.

    2. Ornosternum: Connects episternum with clavicles.

    3. Mesosternum: Projects behind the epicoracoid.

    4. Xiphisternum: Terminal plate.

Pectoral Girdle Structure

  • Composed of:

    • Supras-Scapula: Broad, flat bone.

    • Scapula: Stout, flat bone; attachment for limbs.

    • Clavicle: Rod-like, separates from coracoid.

    • Coracoid: Dumb-bell shaped, connects mid-ventrally with sternum.

Pelvic Girdle Features

  • Supports pelvic region and hind limbs. Each half (os-innominatum) has:

    • Ilium: Connects with lower vertebrae.

    • Pubis: Forms central disc and acetabulum.

    • Ischia: Larger oval bones supporting structure.

Forelimbs of Frogs

  1. Humerus: Short cylindrical bone with a calcified head for articulation.

  2. Radio-Ulna: Composite bone of lower arm, fusion of radius and ulna.

  3. Carpals: Wrist bones arranged in rows, including radiale, intermedium, ulnare, trapezium, trapezoid, capitohematum.

  4. Metacarpals: Five slender supportive bones, first is rudimentary.

  5. Phalanges: Support digits of forelimbs, varying counts per digit.

Hindlimbs of Frogs

  1. Femur: First bone of hindlimb with rounded head for pelvic girdle articulation.

  2. Tibio-Fibula: Longest shank bone, compound structure of tibia and fibula.

  3. Tarsals: Comprises astragalus and calcaneum, vital for foot support.

  4. Metatarsals: Similar to the forelimb, supporting the foot with true digits and an additional small toe.

Comparison Between Human and Frog Skeletons

  • Main Differences: Variations in skull structure, vertebral column design, and limb configuration can be highlighted.

  • Specific Bones in Humans and Frogs: Differences in bone types, structure and number, such as the presence of additional bones or variations in size.