Axial Skeleton Overview

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Questions and Answers

Which bone is not part of the 22 bones that form the adult skull?

Frontal

Parietal

Clavicle (correct)

Temporal

How many pairs of ribs are there in the thoracic cage?

16 pairs

12 pairs (correct)

10 pairs

14 pairs

What is the primary function of the axial skeleton?

Support the appendicular skeleton

Facilitate locomotion

Protect the brain (correct)

Store minerals

What is the characteristic of the joints in the adult skull?

Most are sutured Signup and view all the answers

Which bone provides openings for respiratory and digestive passages?

Ethmoid Signup and view all the answers

Which bones contribute to the formation of the hard palate?

Palatine bones Signup and view all the answers

What structure do the lacrimal bones help form?

Tear duct Signup and view all the answers

Which bone serves as the partition separating the nostrils?

Vomer Signup and view all the answers

Which of the following bones forms part of the cheekbone structure?

Zygomatic bones Signup and view all the answers

How many palatine bones are present in the skull?

2 Signup and view all the answers

Which bones are located at the inferior position within the nasal cavity?

Inferior nasal conchae Signup and view all the answers

Which bone forms the back of the nasal cavity?

Vomer Signup and view all the answers

What role do the inferior nasal conchae play in the skull?

Filtering and warming air Signup and view all the answers

What are the small channels called that radiate from lacunae to the haversian canal?

Canaliculi Signup and view all the answers

How are lamellae organized in spongy bone?

Into thin plates or rods called trabeculae Signup and view all the answers

Where are osteocytes located within bone tissue?

In spaces known as lacunae Signup and view all the answers

What is the primary function of trabeculae in spongy bone?

To reduce the overall weight of the skeleton Signup and view all the answers

What distinguishes spongy bone from compact bone in terms of structure?

Absence of osteons and presence of trabeculae Signup and view all the answers

What are the primary components that make bone hard and strong?

Calcium and phosphate crystals Signup and view all the answers

What is the structural unit of bone called?

Osteon Signup and view all the answers

What is housed within the central canal of an osteon?

Blood vessels Signup and view all the answers

How are the concentric rings of matrix in an osteon referred to?

Lamellae Signup and view all the answers

What role do collagen fibers play in bone structure?

They provide tensile strength. Signup and view all the answers

What is NOT a component of the extracellular matrix in bone?

Adipose tissue Signup and view all the answers

Which of the following statements about osteons is false?

Osteons do not contain blood vessels. Signup and view all the answers

Which component is primarily responsible for the mineralization of bone?

Calcium and phosphate crystals Signup and view all the answers

What is the function of the head of a bone in a joint?

To provide a rounded extension covered in cartilage Signup and view all the answers

What type of bone markings are tubercles associated with?

Tendon or ligament attachment Signup and view all the answers

Which of the following is NOT a feature of compact bone?

Contains a network of trabeculae Signup and view all the answers

What is the primary characteristic that distinguishes spongy bone from compact bone?

Arrangement of trabecular networks Signup and view all the answers

What is the definition of a fossa in bone structure?

A shallow depression on the bone surface Signup and view all the answers

What describes a condyle in bone terminology?

A large rounded prominence for articulation Signup and view all the answers

Which of the following correctly defines the term 'sulcus' in relation to bone markings?

An elongated groove or channel in bone Signup and view all the answers

What is a key difference between osteons and trabeculae?

Osteons are densely packed structures while trabeculae form a network Signup and view all the answers

What is a unique feature of elastic connective tissue?

It contains a high proportion of elastic fibers that allows for recoil. Signup and view all the answers

Which of the following best describes dense irregular connective tissue?

It provides resistance against tension from multiple directions. Signup and view all the answers

What type of cells are found in cartilage tissues, and where are they located?

Chondrocytes housed within lacunae. Signup and view all the answers

Which of the following is a function of adipose tissue?

Storing energy and providing insulation. Signup and view all the answers

What characterizes the extracellular matrix in cartilage?

It contains collagenous fibers and chondroitin sulfates. Signup and view all the answers

What type of cartilage is primarily found in the external ear, providing flexible support?

Elastic cartilage Signup and view all the answers

Which type of cartilage serves a critical role in shock absorption between vertebrae?

Fibrocartilage Signup and view all the answers

Where is hyaline cartilage most abundantly located?

At the ends of long bones Signup and view all the answers

What is the primary function of synovial membranes in the joints?

Secreting lubricating fluid Signup and view all the answers

What distinguishes the cutaneous membrane from other types of membranes?

It is a dry membrane. Signup and view all the answers

What types of membranes line body cavities that open to the exterior?

Mucous membranes Signup and view all the answers

Which membrane helps reduce friction between bones during joint movement?

Synovial membrane Signup and view all the answers

What distinguishes glandular epithelium from covering and lining epithelium?

Glandular epithelium is specialized for secretion. Signup and view all the answers

How do fibroblast-like synoviocytes contribute to joint function?

By secreting synovial fluid Signup and view all the answers

Which characteristic is NOT typical of epithelial tissue?

Presence of blood vessels. Signup and view all the answers

What feature allows epithelial cells to exhibit difference in function and structure?

Cellular polarity. Signup and view all the answers

How does the basement membrane influence epithelial tissue?

It separates epithelial cells from connective tissue. Signup and view all the answers

Why is the rapid reproduction of epithelial cells important?

To enable rapid healing and tissue repair. Signup and view all the answers

Which property is true for both types of epithelial tissue?

They have tightly packed cells. Signup and view all the answers

What defines the apical surface of epithelial tissue?

It faces the external environment or internal cavity. Signup and view all the answers

Which of the following statements about epithelium is correct?

Epithelial cells are fed by diffusion from surrounding connective tissue. Signup and view all the answers

What is a primary function of covering and lining epithelium?

To protect underlying tissues. Signup and view all the answers

Which characteristic of epithelial tissue contributes to its ability to rapidly heal after injury?

High mitotic rate of cells. Signup and view all the answers

What type of membrane lines body cavities that are open to the exterior?

Mucous membranes Signup and view all the answers

Which type of tissue is primarily found lining mucous membranes?

Epithelial tissue Signup and view all the answers

What is the primary purpose of mucus secreted by mucous membranes?

To trap dust, dirt, and pathogens Signup and view all the answers

Which fluid is secreted by serous membranes to reduce friction between organs?

Serous fluid Signup and view all the answers

What is the term for the connective tissue layer that underlies the epithelium of mucous membranes?

Lamina propria Signup and view all the answers

Which of the following describes the structure of serous membranes?

A single layer of flat epithelial cells Signup and view all the answers

How are serous membranes classified based on their location?

Using visceral and parietal terms Signup and view all the answers

What is the main function of serous membranes?

To reduce friction between organs Signup and view all the answers

Which of the following is NOT a major serous membrane?

Lamina propria Signup and view all the answers

What role do goblet cells play in mucous membranes?

They produce mucus. Signup and view all the answers

What is the main function of nonkeratinized stratified squamous epithelium?

Protection against mechanical stress Signup and view all the answers

Which of the following characteristics is typical of pseudostratified columnar epithelium?

Presence of hair-like cilia Signup and view all the answers

What are the two layers that compose the basement membrane?

Lamina lucida and lamina densa Signup and view all the answers

Which of the following best describes the composition of the extracellular matrix (ECM) in connective tissue?

10% large organic molecules and 90% interstitial fluid Signup and view all the answers

Which type of connective tissue fiber is considered the strongest?

Collagen fibers Signup and view all the answers

In which body organs would you typically find transitional epithelium?

Ureters and bladder Signup and view all the answers

What is the role of glycosaminoglycans (GAGs) in connective tissue?

Aid in tissue hydration Signup and view all the answers

Which type of epithelium is characterized by surface cells that are dead and packed with keratin?

Keratinized stratified squamous epithelium Signup and view all the answers

What type of secretion is primarily provided by mucus-secreting cells in pseudostratified columnar epithelium?

Exocrine secretion Signup and view all the answers

Which of the following is a primary component of the supportive framework in connective tissue?

Extracellular matrix Signup and view all the answers

Study Notes

Axial Skeleton

Comprises 22 bones, excluding the temporomandibular joints.
All bones of the adult skull, except temporomandibular joints, are connected by immovable joints called sutures.
Contains 12 pairs of ribs that protect vital organs such as the heart and lungs and form the thoracic cage.
Consists of 33 vertebrae that provide structural support and house the spinal cord.

Skull Bones

Total of 22 skull bones, categorized as follows:
- Eight bones protect the brain: Parietal (2), Temporal (2), Frontal, Occipital, Ethmoid, Sphenoid.
- Fourteen bones shape the face and support respiratory and digestive openings.
Palatine bones (2) form part of the hard palate.
Lacrimal bones (2) aid in tear duct formation.
Vomer is a flat, triangular bone that forms part of the nasal cavity and inferior nasal septum.
Inferior nasal conchae (2) are responsible for filtration and humidification of air entering the nasal cavity.

Bone Markings in Long Bones

Fovea capitis: Small pit on the head of a bone.
Tubercle: Small, rounded process providing muscle attachment.
Sulcus: Groove in a bone's surface.
Head: Rounded, prominent extension forming part of a joint, usually covered by hyaline cartilage.
Fossa: Shallow depression on the bone surface.
Condyle: Large rounded prominence that articulates with another bone.
Facet: Flat surface aiding in joint formation.

Internal Structure of Bones

Two types of bone tissue:
- Compact bone: Dense, containing closely packed osteons or Haversian systems; features a central osteonic canal surrounded by concentric lamellae.
- Spongy bone (cancellous): Lacks osteons; features trabeculae forming a network, reducing skeleton weight.
Bone cells (osteocytes) are located in lacunae between the lamellae.
Canaliculi are small channels that connect lacunae to the central canal for nutrient exchange.

Cartilage Types

Elastic Cartilage: Contains predominantly elastic fibers providing flexible support, notably in the external ear.
Fibrocartilage: Characterized by toughness and shock absorption; primarily located between vertebrae, with a parallel fiber arrangement.
Hyaline Cartilage: Features a network of imperceptible collagen fibers and serves as support; found in costal cartilages of ribs, nose, trachea, larynx, and covers joint ends for padding.

Body Membranes

Mucous Membranes: Line open body cavities (respiratory, digestive, urinary, reproductive); consist of epithelial tissue with goblet cells that produce mucus, providing lubrication and protection against pathogens.
Serous Membranes: Line closed body cavities; composed of mesothelium resting on connective tissue, secreting serous fluid for friction reduction. Divided into visceral and parietal, naming specific cavities like pericardium and pleura.
Cutaneous Membrane: The skin; the thickest and only dry membrane covering the body surface.
Synovial Membranes: Line synovial joints and bursae, providing lubrication and cushioning during joint movement through synovial fluid secreted by synoviocytes.

Epithelial Tissue Characteristics

Composed of closely packed cells with minimal extracellular material; includes both glandular (secretes substances) and covering/lining types (covers surfaces).
Display polarity with distinct apical and basal surfaces, and are avascular but innervated; capable of rapid healing.
Basement membrane separates epithelium from underlying connective tissue, consisting of lamina lucida, lamina densa, and reticular lamina.

Connective Tissue Structure

Composed of extracellular matrix (ECM) with varying compositions; includes specialized matrix-secreting cells (fibroblasts, chondroblasts).
Contains three main fiber types:
- Collagen Fibers: Strong and provide structure.
- Elastic Fibers: Allow stretching and recoil.
- Reticular Fibers: Provide a supportive network.

Types of Connective Tissue

Loose Connective Tissue (Areolar): Forms lamina propria of mucous membranes; lines respiratory, gastrointestinal, and urogenital tracts.
Adipose Tissue: Provides insulation and energy storage, characterized by a "bubble-like" appearance.
Reticular Tissue: Provides support to blood cells in lymphoid organs like lymph nodes and spleen.
Dense Connective Tissue: Includes dense regular (tendons and ligaments) and dense irregular (dermis of skin); elastic connective tissue allows recoil after stretching, found in artery walls.

Skeletal Cartilage Composition

Composed of chondrocytes housed in lacunae within a firm extracellular matrix.
Lacks nerve fibers and is avascular; matrix produced by chondroblasts includes collagen fibers and chondroitin sulfates.

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Description

Explore the essential components of the axial skeleton, which consists of 22 bones including the skull. Learn about the functions of these bones in providing support, movement, and protection. This quiz will enhance your understanding of the skeletal system.