Skeletal System and Bone Structure Quiz

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Questions and Answers

What is one primary function of the skeletal system?

Storage of minerals (correct)

Regulation of body temperature

Transport of nutrients

Production of hormones

Osteocytes are immature bone cells that help with the initial formation of bone.

False

What is contained within the central (Haversian) canal of an osteon?

Blood vessels, nerves, and lymphatic tissue

The ______ are tiny channels that connect lacunae to each other and to the central canal.

canaliculi Signup and view all the answers

Which structure is responsible for maintaining bone density and mineral content?

Osteocytes Signup and view all the answers

Match the following structures of the osteon with their functions:

Central canal = Contains blood vessels and nerves Lacunae = Holds osteocytes Concentric lamellae = Provides structural support Canaliculi = Connects lacunae to central canal Signup and view all the answers

Trabeculae are found in compact bone and provide structural support.

False Signup and view all the answers

Name one way that bones respond to mechanical stress.

They grow thicker and stronger. Signup and view all the answers

What is the primary function of osteoblasts?

Build new bone tissue Signup and view all the answers

Osteoclasts are responsible for building new bone tissue.

False Signup and view all the answers

What type of bone tissue is found at the ends of long bones?

spongy bone Signup and view all the answers

The cytoplasmic extensions of osteocytes allow for ______ with neighboring cells.

communication Signup and view all the answers

Match the following types of bone marrow with their primary function:

Red Bone Marrow = Immune response support Yellow Bone Marrow = Can convert to red marrow in emergencies Signup and view all the answers

Which cell type is primarily responsible for sensing mechanical stress in bones?

Osteocytes Signup and view all the answers

Can yellow bone marrow be converted back into red bone marrow?

True Signup and view all the answers

Name one area in the skeleton where spongy bone tissue is found.

vertebrae Signup and view all the answers

The layer of bone that provides strength and structural support is called ______.

compact bone Signup and view all the answers

What connects the osteocytes in spongy bone to their nutrients?

Canaliculi Signup and view all the answers

The periosteum is involved in growth and repair of bone.

True Signup and view all the answers

What is the function of osteoclasts?

to resorb old or damaged bone tissue Signup and view all the answers

The ______ of long bones is cylindrical and provides structural support.

diaphysis Signup and view all the answers

Match the following structures of long bones to their descriptions:

Epiphysis = Ends of long bone, contains spongy bone Diaphysis = Long cylindrical main portion Periosteum = Connective tissue covering the bone Endosteum = Lining of the medullary cavity Signup and view all the answers

What is the primary function of the medullary cavity?

Fat storage and blood cell production Signup and view all the answers

The epiphyseal line indicates that bone growth has just begun.

False Signup and view all the answers

List one function of the skeletal system.

Support, Protection, Movement, or Mineral storage. Signup and view all the answers

The axial skeleton includes the skull, __________, sternum, ribs, and hyoid bone.

vertebrae Signup and view all the answers

Match each cranial bone to its function:

Frontal = Protects the brain and forms the forehead Occipital = Allows for head nodding and passage of the spinal cord Ethmoid = Aids in smell and forms part of the nasal cavity Sphenoid = Transmits optic nerve for vision Signup and view all the answers

Which of the following is NOT a bone marking?

Crevice Signup and view all the answers

The cranial bones consist of eight bones including the frontal and parietal bones.

True Signup and view all the answers

What is the function of the foramen magnum?

Allows the spinal cord to pass through and connect the brain to the spinal column. Signup and view all the answers

The passage of nerves and blood vessels through bone occurs via __________.

foramina Signup and view all the answers

Which bone is known for having a large opening that facilitates the connection between the brain and spinal cord?

Occipital Signup and view all the answers

The glenoid fossa serves as an attachment point for muscles.

True Signup and view all the answers

What type of cartilage is found in the epiphyseal plate?

Hyaline cartilage. Signup and view all the answers

The __________ is the bony projection that serves as an attachment point for the falx cerebri.

crista galli Signup and view all the answers

Which of the following structures is associated with the auditory system?

Meatus Signup and view all the answers

Match the following markings to their descriptions:

Foramen = Opening for passage of nerves and vessels Fossa = Depression for muscle attachment Process = Projection for muscle attachment Condyle = Rounded end forming joints Signup and view all the answers

What is the primary function of the spinous process of a vertebra?

Provides attachment for muscles and ligaments Signup and view all the answers

The atlas vertebra has a body and spinous process.

False Signup and view all the answers

Which two vertebrae allow you to shake your head 'no'?

Atlas and Axis Signup and view all the answers

The thoracic vertebrae can be identified by their facets for _____ articulation.

rib Signup and view all the answers

Match the following regions of the vertebral column with their descriptions:

Cervical = Seven vertebrae in the neck Thoracic = Twelve vertebrae with rib attachments Lumbar = Five larger vertebrae for lower back support Sacrum = Five fused vertebrae at the base of the spine Signup and view all the answers

What is the structural characteristic of lumbar vertebrae?

They have short, thick processes Signup and view all the answers

The coccyx is formed by the fusion of four to five bones.

True Signup and view all the answers

What type of tissue forms the costal cartilages?

Hyaline cartilage Signup and view all the answers

The _____ is a part of the sternum that typically fuses to the body by age 25.

xiphoid process Signup and view all the answers

Which statement is true regarding true ribs?

They attach directly to the sternum by their own costal cartilage. Signup and view all the answers

What is the primary function of the mandibular fossa?

Socket for the mandibular condyle Signup and view all the answers

The vomer bone is part of the nasal cavity and forms the superior part of the nasal septum.

False Signup and view all the answers

Which bone contributes to the formation of the hard palate?

Maxilla and Palatine Bones Signup and view all the answers

The ______ bone forms the bridge of the nose.

Nasal Signup and view all the answers

Match the following bones with their descriptions:

Maxilla = Forms the anterior portion of the hard palate Zygomatic = Forms the cheekbone Vomer = Forms the inferior part of the nasal septum Mandible = The lower jawbone and only movable facial bone Signup and view all the answers

Which bone is NOT part of the bony wall of the orbits?

Patella Signup and view all the answers

The temporal bone contributes to the zygomatic arch.

True Signup and view all the answers

What are the primary functions of the facial bones?

Support and structure, protection, articulation, airway and sinus function, and muscle attachment. Signup and view all the answers

The ______ process is a rounded projection at the top of the mandible.

Condylar Signup and view all the answers

Match the following facial bones with their functions:

Palatine = Forms part of the hard palate Inferior Nasal Concha = Increases surface area for warming air Lacrimal = Contains the lacrimal sac Zygomatic = Contributes to the cheekbone structure Signup and view all the answers

Which bone forms part of the medial wall of the orbit?

Lacrimal Signup and view all the answers

The inferior nasal concha is flat and located in the upper part of the nasal cavity.

False Signup and view all the answers

What bones make up the nasal septum?

Vomer and perpendicular plate of the ethmoid bone Signup and view all the answers

The _____ bone contributes to the back of the orbit.

Sphenoid Signup and view all the answers

What function does the external auditory meatus serve?

Passage leading to the eardrum Signup and view all the answers

Which of the following bones in the skull is movable?

Mandible Signup and view all the answers

The maxilla is fully movable.

False Signup and view all the answers

Name the four main sutures of the skull.

coronal, sagittal, lambdoid, squamous Signup and view all the answers

The __________ is the smallest ossicle in the middle ear.

stapes Signup and view all the answers

Match the following fontanels with their descriptions:

Anterior = Largest fontanel, diamond-shaped at top of head Posterior = Triangular fontanel at back of head Anterolateral = Located at the junction of frontal, parietal, temporal, and sphenoid bones Posterolateral = Located at the junction of parietal, occipital, and temporal bones Signup and view all the answers

Which suture separates the frontal bone from the parietal bones?

Coronal Suture Signup and view all the answers

Fontanels in a newborn skull are fully ossified at birth.

False Signup and view all the answers

What is the primary function of the paranasal sinuses?

Lightening the weight of the skull and enhancing sound quality during speech Signup and view all the answers

The __________ bone does not articulate with any other bones in the body.

hyoid Signup and view all the answers

What connects the malleus to the incus in the middle ear?

Eardrum Signup and view all the answers

The body of a vertebra provides stability to the spine.

True Signup and view all the answers

How do intervertebral discs assist the spine?

They cushion and absorb vertical shocks. Signup and view all the answers

The __________ process of a vertebra serves as an attachment point for muscles.

transverse Signup and view all the answers

Match the bones with their functions:

Malleus = Transmits sound vibrations from the eardrum to the incus Incus = Acts as a lever between malleus and stapes Stapes = Transmits sound to the inner ear Temporal Bone = Articulates with the mandible at the TMJ Signup and view all the answers

Study Notes

Principle Functions of the Skeletal System

Supports the weight of the body
Works with muscles to maintain posture and produce controlled movements
Involved in mineral and lipid storage
Site of blood cell production
Undergoes extensive remodeling throughout life

Microscopic Structures of Compact Bone

Compact bone is dense and organized into osteons
The main structures of an osteon are:
- Central (Haversian) canal: Contains blood vessels, nerves, and lymphatic tissue, providing nutrients and signaling to bone cells
- Lacunae: Small cavities within bone that hold osteocytes
- Osteocytes: Mature bone cells that live within the lacunae and maintain bone tissue
- Concentric lamellae: Layers of mineralized matrix surrounding the central canal, providing structural support and strength.
- Canaliculi: Tiny channels that connect lacunae to each other and to the central canal, allowing for nutrient exchange and communication between osteocytes.

Osteocytes, Osteoblasts and Osteoclasts

Osteoblasts: Bone-building cells that produce and mineralize new bone matrix
Osteocytes: Mature bone cells that come from osteoblasts, maintain bone tissue, and communicate with other bone cells to regulate bone density.
Osteoclasts: Bone-resorbing cells that break down old or damaged bone tissue.
Collaboration: These cells work together to maintain bone density and strength by balancing bone formation and resorption.

Function of Osteocyte Cytoplasmic Extensions

Connect osteocytes with neighboring osteocytes and other bone cells, facilitating communication and information sharing.
Facilitate nutrient exchange, oxygen, and waste products between osteocytes and surrounding bone tissue.
Help to sense mechanical stress or strain on the bone and signal the need for remodeling.

### Macroscopic Structures of Long Bones

Long bones have a diaphysis (shaft) and two epiphyses (ends)
Diaphysis: Composed primarily of compact bone and contains the medullary cavity, which holds yellow marrow
Epiphyses: Contain spongy bone and red marrow, reducing friction at joints.
Periosteum: A dense connective tissue covering the bone, serving as attachment points for tendons and ligaments and involved in growth and repair
Endosteum: A thin membrane lining the medullary cavity, involved in bone growth, repair, and remodeling.

### Spongy Bone

Found in the ends of long bones, vertebrae, and pelvic bones
Trabeculae are thin, bony plates that provide structural support and distribute forces throughout the bone.
Osteocytes in spongy bone obtain nutrients and oxygen through canaliculi that connect them to the blood vessels in the surrounding bone marrow.

Red Bone Marrow vs. Yellow Bone Marrow

Red bone marrow: Found in the spongy bone of certain bones, contains hematopoietic cells that produce red blood cells, white blood cells, and platelets
Yellow bone marrow: Found in the medullary cavity of long bones, primarily composed of adipose tissue and serves as an energy reserve.
Yellow bone marrow can convert back to red bone marrow in cases of severe blood loss or increased demand for blood cell production

Adult Bones Containing Red Bone Marrow

Pelvic Bones (Ilium)
Sternum
Ribs
Vertebrae (spinal bones)

### Structures of a Long Bone

Epiphysis: Ends of the long bone. The proximal epiphysis is closest to the body trunk, the distal epiphysis is furthest from the body trunk
Diaphysis: Long, cylindrical main portion Provides structural support and strength.
Periosteum: Dense connective tissue covering the bone.
Endosteum: Thin membrane lining the medullary cavity.
Medullary (marrow) Cavity: Central cavity within the diaphysis.
Epiphyseal line or plate: Hyaline cartilage layer that allows for bone growth during childhood and becomes a line when growth stops.

### Functions of the Skeletal System

Support: Provides structural support for the body.
Protection: Protects internal organs.
Movement: Works with muscles to produce movement.
Mineral storage: Stores minerals (calcium and phosphorus) that are essential for many bodily functions.

### Axial vs. Appendicular Skeleton

Axial Skeleton: Includes the skull, vertebrae, sternum, ribs, and hyoid bone. Provides framework for the appendicular skeleton and protects vital organs.
**Appendicular Skeleton: ** Includes the pectoral girdle, pelvic girdle, upper and lower limbs

### Bone Surface Markings

Foramen/Foramina: Openings or holes in a bone that allow for the passage of nerves, blood vessels, and ligaments.
Fossa: Shallow basin-like depression that serves as an attachment point for muscles or forms joints with other bones.
Meatus: Canal-like passageway within a bone.
Process: A projection or bump that provides attachment points for muscles, tendons, and ligaments.
Condyle: A rounded, knuckle-like projection at the end of a bone that forms joints.
Crest: A narrow, ridge-like projection that serves as an attachment point for muscles or ligaments.
Facet: A smooth, flat surface that forms joints with other bones.
Head: A rounded, prominent end of a bone that forms joints.

### Cranial Bones and Features

Frontal Bone: Forms the forehead and the upper part of the eye sockets.
- Supraorbital foramen: A small opening above the eye socket that allows for the passage of the supraorbital nerve and blood vessels.
Ethmoid Bone: Forms part of the nasal cavity and the orbits.
- Crista galli: A bony projection that serves as an attachment point for the falx cerebri.
- Cribriform plate: A horizontal plate with small holes that allows for the passage of olfactory nerves.
- Perpendicular plate: Forms the superior part of the nasal septum.
- Olfactory foramina: Tiny openings in the cribriform plate that allow olfactory nerve fibers to pass through.
Occipital Bone: Forms the back and base of the skull.
- Occipital condyle: Rounded projections that articulate with the first cervical vertebra
- Foramen magnum: A large opening at the base of the skull through which the spinal cord passes.
Sphenoid Bone: Located at the base of the skull.
- Optic foramen: A small opening that allows the optic nerve to pass from the eye to the brain.
Parietal Bones: Form the sides and roof of the skull.
Temporal Bones: Form the sides and base of the skull.
- Mandibular fossa: A depression that forms the socket for the mandibular condyle.
- Styloid process: A slender projection serving as an attachment point for muscles and ligaments.
- Mastoid process: A bony prominence that serves as an attachment point for neck muscles and contains air spaces that help in sound conduction.
- External auditory meatus: The ear canal.

Facial Bones and Features

Mandible: The lower jawbone.
- Condylar process: A rounded projection that articulates with the temporal bone.
Maxilla: The upper jawbones.
- Infraorbital foramen: A small opening below the eye socket that allows passage of the infraorbital nerve and blood vessels.
- Palatine process: Forms the anterior part of the hard palate.
Zygomatic bone: Forms the cheekbone.
Palatine bones: L-shaped bones located at the back of the oral cavity, forming part of the hard palate and the floor of the nasal cavity.
Vomer: A thin, flat bone forming the lower part of the nasal septum.
Inferior nasal concha: Curved bones located in the nasal cavity, increasing surface area to warm and humidify air.
Nasal Bones: Form the bridge of the nose.
Lacrimal Bones: Located in the medial wall of the eye socket.

### Bones Forming the Orbits

Frontal Bone
Sphenoid Bone
Zygomatic Bone
Maxilla
Ethmoid Bone
Lacrimal Bone
Palatine Bone

### Unpaired Cranial and Facial Bones

Frontal Bone
Occipital Bone
Sphenoid Bone
Ethmoid Bone
Mandible
Vomer

Bones Forming the Hard Palate

Maxilla
Palatine Bones

Bones Forming the Nasal Septum

Vomer
Perpendicular Plate of the Ethmoid Bone

### Bones Forming the Zygomatic Arch

Zygomatic Bone
Temporal Bone

### Functions of Facial Bones

Support and Structure: Provide shape and support for the face.
Protection: Help protect the delicate structures of the face.
Articulation: Facilitate the movement of the jaw and support the teeth.

### Fontanels in the Fetal Skull

Soft spots in the fetal skull
Allow for the skull to deform during birth and the brain to grow
Typically close up within the first 18 months of life.

### Features of a Typical Vertebra

Body: The thick, anterior portion that supports weight
Vertebral arch: Forms the posterior portion of the vertebra and encloses the vertebral foramen
Vertebral foramen: Opening through which the spinal cord passes
Spinous process: A bony projection that extends posteriorly from the vertebral arch
Transverse processes: Bony projections that extend laterally from the vertebral arch
Superior and inferior articular processes: Joints that connect one vertebra to the next.

### Vertebrae of the Spinal Column

Cervical vertebrae: 7 bones in the neck
- Atlas (C1): Articulates with the skull, allowing for head nodding
- Axis (C2): Contains the dens, a tooth-like projection that allows for head rotation
Thoracic vertebrae: 12 bones in the chest
- Have articular facets for rib attachment
Lumbar vertebrae: 5 bones in the lower back
- Larger bodies to support more weight
Sacrum: 5 fused vertebrae
Coccyx: 4 fused vertebrae

The Sternum

Manubrium: Uppermost portion
Body: Middle portion
Xiphoid process: Small, pointed projection at the bottom

Types of Ribs

True ribs: First 7 pairs - attach directly to the sternum
False ribs: 8th -10th pairs - attach indirectly to the sternum
Floating ribs: Last 2 pairs - do not attach to the sternum

Facial Bones and Their Functions

Airway and Sinus Function: Facial bones contribute to the nasal cavity and paranasal sinuses, essential for breathing and voice resonance.
Muscle Attachment: Facial bones serve as attachment points for muscles responsible for facial expressions and movements.
Movable Bone in the Skull: The mandible is the only movable bone in the skull, forming the temporomandibular joint with the temporal bone.
Maxilla's Role in Chewing: The maxilla, though primarily fixed, assists in mandible movement during chewing by providing a stable structure for teeth occlusion.

Sutures: Immovable Joints of the Skull

Coronal Suture: Separates the frontal bone from the parietal bones, located at the front of the skull.
Sagittal Suture: Runs along the midline of the skull, separating the parietal bones.
Lambdoid Suture: Forms the boundary between the parietal bones and the occipital bone, resembling an inverted "V."
Squamous Suture: Connects the temporal bone to the parietal bone on the sides of the skull, characterized by a curved shape.

The Fetal Skull: Fontanels and Sutures

Fontanels: "Soft spots" in the newborn skull where ossification is incomplete, allowing for skull compression during birth and brain growth.
Anterior Fontanel: Largest fontanel, diamond-shaped, located at the junction of frontal and parietal bones.
Posterior Fontanel: Smaller, triangular fontanel, located at the junction of parietal and occipital bones.
Anterolateral Fontanel (Sphenoidal): Located on the sides of the head, at the junction of frontal, parietal, temporal, and sphenoid bones
Posterolateral Fontanel (Mastoid): Located at the junction of parietal, occipital, and temporal bones on the sides and back of the head.
Frontal Suture: Usually fuses and disappears by the age of six.

Paranasal Sinuses: Functions and Location

Location: Found in the frontal, sphenoidal, ethmoidal, and maxillary bones.
Functions:
- Weight Reduction: Air-filled cavities lighten the skull, making it easier to support.
- Resonance and Sound Production: Contribute to voice resonance, enhancing sound quality during speech.

Hyoid Bone: Unique Features

Attachment: Does not articulate with any other bones but is suspended from the styloid process of the temporal bone by muscles and ligaments.
Muscle Attachment: The geniohyoid is an important muscle attached to the hyoid bone.

Ossicles of the Middle Ear: Structure and Function

Malleus (Hammer): First ossicle, connected to the eardrum, transmits sound vibrations to the incus.
Incus (Anvil): Middle ossicle, located between malleus and stapes, acts as a lever to transfer vibrations to the stapes.
Stapes (Stirrup): Smallest ossicle, connected to the oval window of the cochlea, transmits vibrations from the incus to the inner ear, amplifying sound.

The Vertebral Column: Structure and Functions

Structure: Composed of vertebrae, intervertebral discs, and spinal nerves.
Functions: Supports the head, protects the spinal cord, provides attachment points for muscles.
Intervertebral Discs: Made of fibrocartilage, cushion and absorb shocks between vertebrae.
Vertebral Foramina: Holes between vertebrae that allow spinal nerves to exit the vertebral column.

Vertebrae: Parts and Functions

Body/Centrum (Vertebral Body): Thick, cylindrical front part, provides weight-bearing support.
Vertebral Foramen: Large hole in the center, forms the vertebral canal for the spinal cord.
Transverse Processes: Lateral projections, attachment points for muscles and ligaments.
Spinous Process: Posterior projection, attachment point for muscles and ligaments, protects the spinal cord.
Superior Articular Process: Upward projection, forms joints with the vertebra above.
Inferior Articular Process: Downward projection, forms joints with the vertebra below.
Facets on Articular Processes: Smooth surfaces, allow for articulation between vertebrae, facilitating movement and flexibility.

Regions of the Vertebral Column

Cervical Vertebrae (7): Neck region, C1 (atlas) and C2 (axis) are specialized for head movement.
Thoracic Vertebrae (12): Chest region, identified by facets for rib articulation.
Lumbar Vertebrae (5): Lower back region, largest vertebrae, support weight and have strong muscle attachments.
Sacrum: Five fused vertebrae, articulates with the pelvic girdle.
Coccyx: Three to five fused bones, forming the tailbone.

The Atlas and Axis: Specialized Functions

Atlas (C1): Articulates with the occipital condyles of the skull, allowing head nodding.
Axis (C2): Has a dens (odontoid process) that allows rotation of the head from side to side.

Thoracic Vertebrae: Rib Articulation

Facets on Thoracic Vertebrae: Articulate with the heads of ribs, allowing rib movement and anchoring them to the spine.

Lumbar Vertebrae: Large and Strong

Lumbar Vertebrae: Largest vertebrae, designed for weight-bearing and strong muscle attachment.

Thoracic Cage: Structure and Functions

Structure: Consists of the sternum, ribs, and costal cartilages.
Functions: Protects vital organs, provides support for respiration.
Sternum: Composed of the manubrium, body, and xiphoid process.
Ribs: 12 pairs, articulate with thoracic vertebrae posteriorly, classified as true, false, or floating.
Costal Cartilages: Hyaline cartilage, connect ribs to the sternum and provide flexibility.
Costal Groove: Running along the inferior surface of ribs, houses blood vessels and nerves.

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Test your knowledge on the skeletal system's functions, bone cell types, and the structure of osteons. This quiz covers essential concepts related to bone tissue and its response to mechanical stress. Ideal for students studying human anatomy.