Skeletal-System-of-the-Frog

Types of Skeletons

• Exoskeleton

  • Definition: An external, hard encasement on the surface of an organism.

  • Examples: Crabs, insects.

  • Functions:

    • Provides defense against predators.

    • Supports the body.

    • Allows movement through contraction of attached muscles.

• Endoskeleton

  • Definition: Hard, mineralized structures located within the soft tissues of organisms.

  • Examples: Frogs, humans.

  • Functions:

    • Provides support for the body.

    • Protects internal organs.

    • Enables movement through contraction of muscles attached to the skeleton.

Skeletal System of Frogs

• Number of bones: Approximately 140 (varies by species).

• Classification: Tetrapod vertebrates (four legs and a backbone).

• Growth:

  • Frogs start life as tadpoles without bones (cartilaginous tissue).

  • Process of ossification: Cartilaginous tissue forms into bones during metamorphosis.

Unique Features of Frog Skeleton

• Absence of Neck: Frogs cannot turn or raise/lower their heads, enhancing safety with a rigid spine.

• Absence of Tail: Loss of tail aids in jumping; developed a urostyle for movement.

• Absence of Ribs: Frogs utilize their mouths to decrease lung pressure instead of ribs.

Frog's Skeletal System Components

Major Parts

1. Skull

   • Structure: Triangular shape with incomplete ossification.

   • Regions: Cranium, upper jaw, mandible.

     • Cranium: Protects the brain.

     • Upper Jaw: Supports the mouth border.

     • Mandible: Houses lower jaw parts.

2. Vertebral Column

   • Contains up to 10 vertebrae; no true joints.

   • Functions: Protect spinal cord and provide structural support.

3. Girdles

   • Pectoral Girdle: Connects the forelimbs to the body and protects vital organs.

   • Pelvic Girdle: Connects hind limbs to the spine and supports locomotion.

Skull Anatomy of Frogs

Cranium Components

• Cranium: Protects the brain.

• Upper Jaw Components:

  1. Premaxilla: Upper teeth holder.

  2. Maxilla: Holds small teeth.

  3. Quadratojugal: Supports jaw movement.

  4. Nasal bone: Protects nasal cavity, aids respiration.

  5. Sphenethmoid: Forms roof of nasal cavity.

  6. Squamosal: Connects jaw to skull.

  7. Foramen magnum: Joins skull to vertebral column.

Parts of Mandible

1. Dentary: Front part of lower jaw.

2. Angulosphenial: Largest bone of the lower jaw.

3. Coronary Process: Attachment site for jaw muscles.

Comparison: Frog vs. Human Skeletons

• Skull: Frog skull is flatter, human is rounder.

• Vertebral Columns:

  • Frog: 10 vertebrae, no ribs.

  • Human: 24 vertebrae forming true joints.

Frog's Girdles Overview

Pectoral Girdle Components

1. Episternum: Muscular attachment.

2. Omosternum: Absorbs shock during landing.

3. Scapula: Supports forelimb movement.

4. Coracoid: Provides structural support.

5. Glenoid Cavity: Joint for forelimb movement.

Pelvic Girdle Functions

• Composition: Ilium, ischium, pubis ( protects internal organs).

• Supports hind limbs for jumping and swimming.

Frog's Limbs

Forelimbs

• Characteristics: Shorter and broader for better maneuverability.

• Structure: Include humerus and radio-ulna.

Hindlimbs

• Specialization for jumping and swimming with longer and slender digits.

• Structure: Includes femur and tibio-fibula.