Questions and Answers
What comprises the skeletal system?
Bones, cartilages, and ligaments
What are the primary functions of the skeletal system? (Select all that apply)
How many bones are there in an adult human body?
206
The axial skeleton includes bones of the upper limbs.
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What is the total bone count of the axial skeleton?
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What is the only movable bone of the skull?
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What are the subdivisions of the skull? (Select all that apply)
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What do the cranial fossae correspond to?
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Which bones make up the brain case?
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Study Notes
Overview of the Skeletal System
- Comprises bones, cartilages, and ligaments, providing support and shape to the body.
- Total adult bones count: 206, higher in children due to bone fusion during growth.
Primary Functions of the Skeleton
- Provides rigid internal structure to support body weight against gravity.
- Serves as a framework for muscle action, enabling movement.
Specialization of Skeleton
- Lower Skeleton: Specialized for stability during walking and running.
- Upper Skeleton: Allows greater mobility and range of motion for carrying and turning movements.
Additional Functions
- Protection: Shields vital internal organs (brain, spinal cord, heart, lungs, pelvic organs).
- Storage: Stores essential minerals like calcium and phosphate; bone marrow produces blood cells and stores fat.
Divisions of the Skeleton
- Divided into two major divisions: Axial and Appendicular.
Axial Skeleton
- Forms the vertical, central axis of the body.
- Consists of bones of the head, neck, chest, and back.
- Protects the brain, spinal cord, heart, and lungs.
- Functions as an attachment site for muscles involved in head, neck, back, and limb movement.
- Total bones in the axial skeleton: 80.
Components of the Axial Skeleton
- Skull: 22 bones.
- Vertebral Column: 24 vertebrae, sacrum, and coccyx.
- Thoracic Cage: Comprises 12 pairs of ribs and the sternum.
- Associated Bones: Includes hyoid bone and ear ossicles (3 in each ear).
Appendicular Skeleton
- Includes all bones of the upper and lower limbs.
- Contains bones that attach limbs to the axial skeleton.
- Total bones in the appendicular skeleton: 126.
Overview of the Skull
- Cranium: Skeletal structure of the head that supports the face and protects the brain.
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Subdivisions:
- Facial Bones: Support facial structures and form the nasal cavity; enclose eyeballs and support teeth.
- Brain Case (Cranial Vault): Surrounds and protects the brain and houses ear structures.
Composition of the Skull
- Total bones: 22 individual bones, with 21 being immobile.
- The mandible is the only movable bone.
Anterior View of the Skull
- Facial Features: Provide support for eyes and facial structures.
- Orbits: Bony sockets for eyeballs and related muscles.
- Supraorbital Margin: Contains the Supraorbital Foramen for sensory nerve passage to the forehead.
- Infraorbital Foramen: Supplies anterior face sensory nerves below the orbit.
Nasal Cavity Structure
- Divided by the nasal septum: upper portion formed by the perpendicular plate of the ethmoid bone; lower portion by vomer bone.
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Nasal Conchae:
- Inferior Nasal Concha: Independent bone.
- Middle and Superior Nasal Conchae: Parts of the ethmoid bone.
Lateral View of the Skull
- Brain Case: Large upper portion protecting the brain.
- Jaws and Teeth: Upper and lower jaws with teeth dominate the lower portion.
- Zygomatic Arch: Bony arch from cheek to ear canal, formed by the Temporal Process and Zygomatic Process.
Overview of the Brain Case
- Contains and protects the brain.
- Divided into:
- Cranial Cavity: Interior space for the brain.
- Calvaria (Skullcap): Rounded top of the skull.
- Base of the Skull: Complex area for cranial nerves, blood vessels, and the spinal cord.
- Cranial Fossae: Subdivided into anterior, middle, and posterior fossae.
Bones of the Brain Case
- Total bones: 8 (paired and unpaired).
- Paired Bones: Parietal and temporal bones.
- Unpaired Bones: Frontal, occipital, sphenoid, and ethmoid bones.
Specific Bones of the Brain Case
- Parietal Bone: Most of the upper lateral side, borders the frontal, temporal, and occipital bones.
- Temporal Bone: Forms the lower lateral side, includes the flattened squamous portion and the zygomatic process.
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Description
Explore the Axial Skeleton in this quiz, which covers key components of the skeletal system, including bones, cartilages, and ligaments. With a focus on the primary functions, this quiz will help you understand how the axial skeleton supports and shapes the human body.
