Bone Structure and Functions

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Questions and Answers

Which type of joint allows for back-and-forth motion between nearly flat or slightly curved surfaces?

Gliding joint (correct)

Hinge joint

Pivot joint

Condylar joint

What type of joint is formed when a convex surface fits into a concave surface, allowing movement in one plane only?

Gliding joint

Hinge joint (correct)

Condylar joint

Saddle joint

Which joint movement describes the action of moving a body part away from the midline?

Flexion

Abduction (correct)

Adduction

Rotation

In which type of joint does a cylindrical surface rotate within a ring of bone and fibrous tissue?

Pivot joint Signup and view all the answers

Which joint type consists of articulating surfaces that have both concave and convex areas, allowing a wide range of motion?

Saddle joint Signup and view all the answers

What are osteoblasts called when they become enclosed in bony tissue?

Osteocytes Signup and view all the answers

Which of the following describes the primary ossification center?

It forms through the invasion of blood vessels and osteoblasts. Signup and view all the answers

What role do osteoclasts play in bone tissue?

They tear down calcified bone matrix. Signup and view all the answers

What is the epiphyseal plate primarily composed of?

Cartilage cells undergoing mitosis Signup and view all the answers

Which factor does NOT influence bone development and growth?

Bone density Signup and view all the answers

How do bones contribute to bodily support?

They provide structure for the pelvis and limbs. Signup and view all the answers

What is the process by which osteoclasts and osteoblasts work together to maintain bone health?

Resorption and deposition Signup and view all the answers

What occurs in the diaphysis during endochondral ossification?

Cartilage is broken down and replaced with bone. Signup and view all the answers

Which vertebra is known for supporting the head as a bony ring?

Atlas Signup and view all the answers

What distinguishes cervical vertebrae from the others?

Presence of bifid spinous processes Signup and view all the answers

What is the main function of the thoracic cage?

To protect thoracic and upper abdominal organs Signup and view all the answers

How many pairs of true ribs are there?

7 Signup and view all the answers

Which structure is formed by five fused vertebrae?

Sacrum Signup and view all the answers

What feature do the thoracic vertebrae possess that distinguishes them from cervical vertebrae?

Articulation with ribs Signup and view all the answers

Which bones make up the coccyx?

Four fused vertebrae Signup and view all the answers

What type of vertebrae are larger and stronger than cervical vertebrae?

Thoracic vertebrae Signup and view all the answers

What is the primary function of the periosteum in long bones?

To protect the bone and provide attachment for ligaments and tendons Signup and view all the answers

Which type of bone is characterized by a hollow medullary cavity filled with marrow?

Long bone Signup and view all the answers

Which mechanism describes how bones are formed within connective tissue layers?

Intramembranous ossification Signup and view all the answers

What is the role of osteocytes in bone structure?

Passing nutrients and gases through the matrix Signup and view all the answers

Which of the following describes the organization of osteocytes in compact bone?

Arranged in concentric circles around osteonic canals Signup and view all the answers

What type of cartilage covers the epiphyses of long bones?

Hyaline cartilage Signup and view all the answers

Which of the following is true about spongy bone compared to compact bone?

Osteocytes in spongy bone are not arranged around osteonic canals Signup and view all the answers

What is the primary consideration of bone shape in relation to its function?

Certain shapes are linked to weight bearing Signup and view all the answers

What are the primary functions of red marrow?

Formation of red blood cells, white blood cells, and platelets Signup and view all the answers

Which component of a lever is the point around which the lever pivots?

The fulcrum Signup and view all the answers

What does yellow marrow primarily do?

Store fat Signup and view all the answers

Which structure is NOT a feature of the temporal bone?

Sella turcica Signup and view all the answers

Which structure is NOT found in the axial skeleton?

Scapulae Signup and view all the answers

Which bone contributes to the formation of the nasal cavity and hard palate?

Maxillae Signup and view all the answers

Which of the following bones is classified as a cranial bone?

Frontal bone Signup and view all the answers

What feature is unique to the ethmoid bone?

Crista galli Signup and view all the answers

Which of the following substances is stored in bones as an inorganic salt?

Calcium phosphate Signup and view all the answers

Which of the following bones is fragile and supports mucous membranes in the nasal cavity?

Inferior nasal conchae Signup and view all the answers

What is one major function of the cranial bones?

Enclose and protect the brain Signup and view all the answers

Which statement about the infantile skull is true?

It contains fontanels to aid in childbirth. Signup and view all the answers

What happens to calcium levels in the blood when they are low?

Osteoclasts release calcium from bones Signup and view all the answers

What is the primary purpose of the vertebral column?

To form the vertical axis of the skeleton Signup and view all the answers

Which part of a typical vertebra is primarily responsible for weight support?

Drum-shaped body Signup and view all the answers

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

Lacrimal bones Signup and view all the answers

Study Notes

Introduction

Bones are made of various tissues, acting as organs.
Bone functions include supporting muscles, providing protection, producing blood cells, and storing minerals.

Bone Structure

Bone Classification

Bones differ in size and shape, but share common characteristics.

Parts of a Long Bone

Epiphyses: Expanded ends of bones, forming joints with adjacent bones, covered by articular cartilage.
Diaphysis: The shaft of the bone.
Periosteum: A tough connective tissue layer covering the bone, continuous with ligaments and tendons.
Compact Bone: Forms the diaphysis wall.
Spongy Bone: Fills epiphyses for reduced weight.
Medullary Cavity: Hollow space in the diaphysis, lined with endosteum and containing marrow.

Microscopic Structure

Osteocytes: Bone cells located within lacunae in concentric circles around osteonic canals.
Canaliculi: Channels that connect osteocytes, allowing nutrient and waste exchange.
Intercellular Material: Collagen and inorganic salts form the bone matrix.
Osteons: Compact bone's organized structures of osteocytes and intercellular material, cemented together.
Osteonic Canals: Contain blood vessels and nerve fibers; connected by transverse perforating canals.
Spongy Bone: Differs, with osteocytes and intercellular material not organized around osteons.

Bone Development and Growth

Bones replace connective tissue in the fetus.
Intramembranous Bones: Develop in sheet-like layers, such as skull bones.
Endochondral Bones: Form through replacing cartilage models, most skeletal bones.
- Cartilage is broken down and replaced with bone, starting from a primary ossification center in the diaphysis.
Bone growth occurs at the epiphyseal plates.
- Cartilage cells undergo mitosis, which are then replaced by osteoblasts.
Osteoblasts lay down compact bone exteriorly to the spongy bone.
Secondary ossification centers form in the epiphyses, enabling longitudinal bone growth.

Bone Function

Support and Protection: Bones provide the structure for the body and protect organs (brain, ears, eyes).
Body Movement: Serve as levers with components: a rigid bar, pivot point, object moved, and the force moving the object.
Blood Cell Formation: Red marrow within spongy bone forms red blood cells, white blood cells, and platelets.
Storage of Inorganic Salts: Bone stores calcium phosphate for metabolic processes; calcium release in blood-low times; uptake when levels are high.
Harmful Element Accumulation: Bones can store harmful elements (lead, strontium).

Skeletal Organization

Axial Skeleton: Skull, hyoid bone, vertebral column, and thoracic cage.
Appendicular Skeleton: Pectoral girdle, upper limbs, pelvic girdle, and lower limbs.

Skull

Cranium: Encloses the brain, provides muscle attachment points, contains air-filled sinuses for reduced weight.
Facial Skeleton: Forms the basic face, providing attachment to muscles.

Vertebral Column

Vertebrae: Separated by intervertebral disks, have a drum-shaped body and vertebral arch.
Cervical Vertebrae: The smallest, the first (atlas) supports the head, the second (axis) allows head rotation.
Thoracic Vertebrae: Articulate with ribs.
Lumbar Vertebrae: The largest and strongest, supporting the body's weight.
Sacrum: Formed by fused vertebrae, base of the vertebral column.
Coccyx: The lowermost part of the vertebral column, composed of fused vertebrae.

Thoracic Cage

ribs, thoracic vertebrae, sternum, and costal cartilages.
Supports pectoral girdle, upper limbs, aids in respiration, and protects thoracic and upper abdominal organs.

Pectoral Girdle

The pectoral girdle (clavicles & scapulae) support the upper limbs.

Upper Limb

Humerus: Forms upper arm, articulates with scapula, radius, and ulna.
Radius: Thumb side of forearm
Ulna: Longer bone in forearm.
Hand: Wrist (carpals), metacarpals, and phalanges (fingers)

Pelvic Girdle

Coxal Bones: Form hip bones, comprised of ilium, ischium, and pubis, support the lower body and protect pelvic organs, fuses with sacrum.

Lower Limb

Femur: Thigh bone, longest bone in the body.
Tibia: Shinbone, supports body weight, articulates with the femur and tarsal bones.
Fibula: Slender bone, lies next to tibia.
Foot: Ankle (tarsals), instep (metatarsals), and toes (phalanges).

Joints

Joints (articulations): Junctions between bones, enabling various movements, classified based on movement (immovable, slightly movable, freely movable) or type of tissue binding them together (fibrous, cartilaginous, synovial ).

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Description

Explore the intricate details of bone structure, including classifications and parts of long bones. Learn how bones support the body, protect organs, and contribute to blood cell production. This quiz covers essential concepts of bone anatomy and physiology.