Skeletal System Functions and Structure

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Questions and Answers

What is the primary function of the hydroxyapatite crystals in bone?

To regulate the mineralization of the bone (correct)

To protect the bone from fractures and injuries

To provide mechanical strength to the bone

To facilitate bone growth and development

What type of bone is found in the wrist and ankle?

Irregular bones

Short bones (correct)

Long bones

Flat bones

What is the function of the periosteum in the skeletal system?

To provide a surface for muscle attachment

To store minerals and nutrients

To produce blood cells

To surround and nourish the diaphysis (correct)

What is the primary component of tendons and ligaments?

Collagen Signup and view all the answers

What is the function of the epiphyseal plate?

To facilitate bone growth in length Signup and view all the answers

What is the composition of the medullary cavity?

Yellow marrow and red marrow Signup and view all the answers

What is the primary function of osteoclasts in the process of bone remodeling?

Removal of existing bone tissue Signup and view all the answers

Where does bone growth occur through the process of endochondral ossification?

At the epiphyseal plate Signup and view all the answers

What is the role of chondrocytes in the process of endochondral ossification?

To proliferate, enlarge, and die, replaced by bone tissue Signup and view all the answers

What is the term for the process of bone reshaping and adjustment?

Bone remodeling Signup and view all the answers

Which hormone is responsible for increasing blood calcium levels by stimulating bone breakdown?

Parathyroid hormone (PTH) Signup and view all the answers

What is the term for the network of fibers and cartilage that forms in the damaged area during bone repair?

Callus Signup and view all the answers

What is the name of the bone that rests on the first vertebra of the vertebral column?

Occipital condyles Signup and view all the answers

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

Lacrimal Bones Signup and view all the answers

What is the name of the bone that contains the pituitary gland?

Sella Turcica Signup and view all the answers

How many bones make up the facial bones?

14 Signup and view all the answers

What is the name of the bone that spans the width of the skull?

Sphenoid Bone Signup and view all the answers

What is the name of the U-shaped bone that provides attachment to tongue muscles?

Hyoid Bone Signup and view all the answers

What type of joint is characterized by movement in a single plane?

Hinge joint Signup and view all the answers

Which type of movement involves rotation of the forearm so that the palm faces up?

Supination Signup and view all the answers

What type of joint is characterized by a ball and socket structure?

Ball and socket joint Signup and view all the answers

What type of movement involves the movement of the foot toward the shin?

Dorsiflexion Signup and view all the answers

What is the term for the movement of a part of the body around its long axis?

Rotation Signup and view all the answers

What type of joint is characterized by an elongated ball and socket structure?

Ellipsoid joint Signup and view all the answers

What is the location of the radial tuberosity?

On the radius Signup and view all the answers

Which of the following bones is NOT part of the pelvic girdle?

Scapula Signup and view all the answers

What is the name of the process that forms most of the elbow joint?

Trochlear notch Signup and view all the answers

What is the name of the bony landmark where the deltoid muscle attaches?

Deltoid tuberosity Signup and view all the answers

How many carpal bones are in the wrist?

8 Signup and view all the answers

What is the name of the joint that joins the sacrum posteriorly to the coxal bones?

Sacroiliac joints Signup and view all the answers

Study Notes

Skeletal System

The skeletal system consists of bones, cartilage, tendons, and ligaments.
Functions:
Support
Protection
Movement
Storage
Blood cell production

Extracellular Matrix

Composed of connective tissues
Components:
Collagen: tough, ropelike protein
Proteoglycans: large molecules consisting of polysaccharides attached to core proteins
Tendons and ligaments: large amounts of collagen fibers
Cartilage: contains collagen and proteoglycans
Bone: contains collagen and minerals (calcium and phosphate)

Bone Structure

General features:
Long bones: upper and lower limbs
Short bones: wrist and ankle
Irregular bones: vertebrae and facial bones
Long bones:
Diaphysis: central shaft
Epiphysis: ends
Epiphyseal plates: growth plate; where the bone grows in length
Articular cartilage: covers the ends of the epiphyses
Epiphyseal line: bone growth stops, and the epiphyseal plate is replaced by bone
Medullary cavity: large cavity in the diaphysis; contains the marrow
Layers of a bone:
Periosteum: outermost layer; surrounds the diaphysis; contains blood vessels, nerves, and osteoblasts
Endosteum: innermost layer; lines the medullary cavity (thinner connective tissue)

Bone Growth and Development

Bone growth: deposition of new bone lamellae onto existing bone
Bone elongation occurs at the epiphyseal plate; leads to increase in height (endochondral ossification)
Chondrocytes: cartilage cells; increase in number, enlarge, and die
Primary ossification center: where bone first begins to appear
Osteoclasts: cells that remove calcified cartilage matrix
Secondary ossification center: forms in the epiphyses

Bone Remodeling

Removal of existing bone by osteoclasts
Deposition of new bone by osteoblasts
Responsible for change in bone shape, bone adjustment, repair, and calcium ion regulation

Bone Repair

Clot is formed in the damaged area
Blood vessels and cells invade the clot and form a callus (network of fibers and islets of cartilage)
Osteoblasts enter the callus and form a spongy bone
Bone is slowly remodeled to compact bone

Bone and Calcium Homeostasis

Osteoclasts remove calcium, increasing blood calcium levels
Osteoblasts deposit calcium, decreasing blood calcium levels
Hormones that maintain calcium homeostasis:
Parathyroid hormone (PTH)
Occipital bone

Cranium

Occipital bone: inferior and posterior bone of the cranium; lambdoid suture
Foramen magnum: where the spinal cord joins the brain
Occipital condyles: rests on the first vertebra of the vertebral column
Foramen ovale: allows the fiber of cranial nerve 5 to pass

Sphenoid Bone

Butterfly-shaped bone that spans the width of the skull
Sella Turcica: saddle-shaped structure at the central region; contains the pituitary gland

Ethmoid Bone

Irregularly shaped bone that lies anterior to the sphenoid bone

Facial Bones

14 bones; 13 solidly connected, 1 movable (mandible)
Holds the facial muscles in place
Joined together by sutures (interlocking, immovable)
Maxillae: main bones of the face; carries the upper teeth
Palatine bones: lies posterior to the palatine processes of the maxilla
Zygomatic bones: cheekbones
Lacrimal bones: bones forming part of the medial wall of each orbit
Nasal bones: bones forming the bridge of the nose
Inferior nasal conchae: thin curved bones projecting from the lateral wall of the nasal cavity
Vomer bone: single bone in the median of the nasal cavity
Mandible: lower jaw; only freely movable joint of the face

Hyoid Bone

U-shaped bone; provides attachment to tongue muscles; elevates the larynx during speech and swallowing

Joints

Types:
Hinge joints: permit movement in one plane only; elbow and knee joints
Pivot joints: restrict movement to rotation around a single axis; rotation that occurs between the axis and atlas; articulation between the ulna and radius
Ball and socket joints: consist of a ball (head) and a socket; shoulder and hip joints
Ellipsoid/con dyloid joints: elongated ball and socket joints; joint between the occipital condyles (skull) and the atlas (vertebral column); joints between the metacarpals and phalanges

Types of Movement

Flexion: movement that takes place in a frontal/coronal plane
Extension: movement that takes place in a posterior direction
Lateral flexion: movement of the trunk in the coronal plane
Abduction: movement away from the median plane
Adduction: movement toward the median plane
Pronation: rotation of the forearm so that the palm is down
Supination: rotation of the forearm so that the palm faces up
Eversion: opposite movement of the foot so that the sole faces in a lateral direction
Inversion: movement of the foot so that the sole faces medially
Rotation: movement of a part of the body around its long axis
Circumduction: combination in sequence of the flexion, extension, abduction, and adduction

Upper Limb

Regions:
Arm: region between the shoulder and the elbow; contains the humerus
Forearm: region between the elbow and the wrist; contains the radius and ulna
Wrist: short region between the forearm and the hand; contains 8 carpal bones
Hand: 5 metacarpal bones are attached to the carpal bones; phalanges are 3 small bones on each finger

Pelvic Girdle

Where lower limbs attach to the body
Coxal bones: hip bones; join each other anteriorly and the sacrum posteriorly to form a ring of bone called the pelvic girdle
Ilium: most superior
Ischium: inferior and posterior; sit-down bone
Pubis: inferior and anterior
Iliac crest: seen along the superior margin of each ilium
Anterior superior iliac spine: important hip landmark; anterior end of the iliac crest
Pubic symphysis: where coxal bones join anteriorly
Sacroiliac joints: joins the sacrum posteriorly
Acetabulum: socket of the hip joint

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Description

Learn about the skeletal system, its functions, and components including bones, cartilage, tendons, and ligaments. Understand the role of collagen, proteoglycans, and minerals in the skeletal system. Test your knowledge of the skeletal system's structure and functions.