Essentials of Human Anatomy and Physiology: Chapter 5 The Skeletal System

What are the functions of the fontanels? (3)

- Allow skull compression during birth - Allow the brain to grow during later pregnancy and infancy - Convert to bone within 24 months after birth

Explain Rheumatoid Arthritis (3)

- An autoimmune disease (the immune system attacks the joints) - Symptoms begin with bilateral inflammation of certain joints - Often leads to deformities

Features of Synovial Joints (4)

- Articular catilage (hyaline cartilage) covers the ends of bones - Articular capsule encloses joint surfaces and lined with synovial membrane - Joint cavity is filled with synovial fluid - Reinforcing ligaments

What are synovial joints? (2)

- Articulating bones are separated by a joint cavity - Synovial fluid is found in the joint cavity

Bones are remodeled in response of two factors, what are they?

- Blood calcium levels - Pull of gravity and muscles on the skeleton

What is osteoporosis? (4)

- Bone-thinning disease. - Disease makes bones fragile and bones can easily fracture - Vertebral collapse results in kyphosis (aka Dowager's Hump) - Estrogen aids in health and normal density of a female skeleton (It afflicts 50% of women over age 65 and 20% of men over the age 70)

Cartilage remains in isolated as ...

- Bridge of a nose - Parts of ribs - Joints

Describe the Perforating (Volkmann's) canal

- Canal perpendicular to the central canal - Carries blood vessels and nerves

Describe Lacunae

- Cavities containing bone cells (osteocytes) - Arranged in concentric rings called lamellae

What is Marrow (Medullary) Cavity?

- Cavity inside of the shaft - Contains yellow marrow (mostly fat) in adults - Contains red marrow for blood cell formation

Two Classifications of Bone Fractures

- Closed (simple) fracture: break that does not penetrate the skin - Open (compound) fracture: broken bone penetrates through the skin

Common Types of Fractures

- Comminuted: bone breaks into many fragments - Compression: bone is crushed - Depressed: broken bone portion is pressed inward - Impacted: broken bone ends are forced into each other - Spiral: ragged break occurs when excessive twisting forces are applied to a bone - Greenstick: bone breaks incompletely

What is Articular Cartilage and what does it do?

- Covers the external surface of the epiphyses - Made of hyaline cartilage - Decreases friction at joint surfaces

Anatomy of a Long Bone (2)

- Diaphysis and Epiphysis

What are the three structural classifications of joints?

- Fibrous joints (generally immovable) - Cartilaginous joints (immovable or slightly moveable) - Synovial joints (freely movable)

Classification of Short Bones

- Generally cube-shaped - Contain mostly spongy bone - Includes bones of the wrist and ankle - Sesamoid bones are a type of short bone which form within tendons (patella) Example: Carpals and Tarsals

Functions of Joints (2)

- Hold bones together - Allow for mobility

Classification of Irregular Bones

- Irregular shape - Does not fit into other bone classification categories Example: Vertebrae and Hip Bones

What are three things that make up the appendicular skeleton?

- Limbs (appendages) - Pectoral Girdle - Pelvic Girdle

Explain bone development in a Fetus (3)

- Long bones are formed of hyaline cartilage - Flat bones begin as fibrous membranes - Flat and long bone models are converted to bone

Explain Osteoarthritis (2)

- Most common chronic arthritis - Probably related to normal aging processes - Known as the "Wear and Tear" arthritis

How does the bone growth happen?

- Older cartilage ossified - Cartilage is broken - Enclosed cartilage is digested away, opening up a medullary cavity - Bone replaces cartilage through the action osteoblasts - Bones are remodeled and lengthened until growth stops

Describe the Central (Haversian) canal

- Opening in the center of an osteon - Carries blood vessels and nerves

What are the three clinical forms of arthritis?

- Osteoarthritis - Rheumatoid Arthritis - Gouty Arthritis

Types of Bone Cells

- Osteocytes: mature bone cells - Osteoblasts: bone forming cells - Osteoclasts: giant bone destroying cells (break down bone matrix for remodeling and release of calcium in response to parathyroid hormone)

What is Periosteum?

- Outside covering of the diaphysis - Fibrous connective tissue membrane

Explain Arthritis (3)

- Over 100 different types - Most widespread crippling disease in the US - Initial symptoms: pain, stiffness, swelling of the joint

Anatomy of a Long Bone (7)

- Periosteum - Perforating (Sharpey's) Fibers - Arteries - Articular Cartilage - Epiphyseal Plate - Epiphyseal Line - Marrow (Medullary) Cavity

What is Epiphyseal Line?

- Remnant of the epiphyseal plate - Seen in adult bones

Describe Lamallae

- Rings around the central canal - Sites of lacunae

What are the three types of fibrous joints?

- Sutures (immobile) - Syndesmoses (allows more movement than sutures but still immobile) - Gomphosis (immoble)

What are the three functional classifications of joints?

- Synarthroses (immovable joints) - Amphiarthroses (slightly moveable joints) - Diarthroses (freely movable joints)

Classification of Flat Bones

- Thin, flattened, and usually curved - Two think layers of compact bone surround a layer spongy bone Example: Skull, Ribs, and Sternum

Describe Canaliculi

- Tiny canals - Radiate from the central canal to lacunae - Form a transport system connecting all bone cells to a nutrient supply

Classification of Long Bones

- Typically Longer than they are wide - Shaft with heads situated at both ends - Contain mostly compact bone - All of the bones of the limbs (except wrist, ankle, and kneecap bones) Example: Femur and Humerus

Five major functions of the skeletal system

1.Support: rigid, strong bone is well suited for bearing weight and is the major supporting tissue of the body. 2. Protection: bone is hard and protects the organs it surrounds. 3. Movement: skeletal muscles attach to bones by tendons, which are strong bands of connective tissue. 4. Storage: some minerals in the blood are taken into bone and stored. 5. Blood cell production: many bones contain cavities filled with red bone marrow, which gives rise to blood cells and platelets.

How many bones does an adult skeleton have?

206 Bones

How many parts is the Axial Skeleton divided into?

3

How many normal curvatures of the spine are there?

4 (cervical, thoracic, lumbar and sacral)

Describe the Osteon (Haversian system)

A unit of bone containing central canal and matrix rings

During what, does epiphyseal becomes ossified and long bone growth ends?

Adolescence

Two Subdivisions of the Skeleton

Axial Skeleton and Appendicular Skeleton

What are cartilaginous joints?

Bones connected by cartilage

What is Appositional Growth?

Bones grow in width

What are fibrous joints?

Bones united by collagenic fibers

4 Parts of the Skeleton System

Bones, Joints, Cartilages, Ligaments

What is a Fracture?

Break in a bone

What are the two structures associated with the synovial joints?

Bursae and Tendon Sheath

What shape are primary curvatures in newborns?

C-shaped

Secondary curvatures are located where? (spinal curvatures)

Cervical and Lumbar regions

Two Basic Types of Bone Tissue

Compact Bone and Spongy Bone

What is Epiphysis?

Ends of the bone and composed of mostly spongy bone

What does bone growth (Ossification) allow?

Epiphyseal plates allow for lengthwise growth of long bone during childhood

(T/F) 2 year olds - their skull is smaller in proportion to their bodies compared to that of an adult.

FALSE, skull is larger in proportion to the body compared to that of an adult

(T/F) At birth, the skull bones are complete.

FALSE, the skull bones are incomplete at birth.

(T/F) Secondary curvatures develop before birth.

FALSE, they develop after birth

During development, bone is replaced by cartilage. (T/F)

FALSE. During development, much of hyaline cartilage is replaced by bone.

What are fontanels?

Fibrous membranes connecting to the cranial bones

What is Epiphyseal Plate?

Flat plate of hyaline cartilage seen in young, growing bone

What are the "soft spots" where the skull bones are joined by fibrous membranes called?

Fontanels

The Axial Skeleton does what?

Forms the longitudinal axis of the body

Two Ways Joints are Classified

Functionally and Structurally

In embryos, the skeleton is primarily _______?

Hyaline cartilage

Abnormal normal curvature of the thoracic region of the spine resulting in a hunch back.

Kyphosis

Bones are classified as...

Long, Short, Flat, or Irregular

Name of the condition where the spine has a greater lumber curvature than normal.

Lordosis

Bone markings are sites of attachments for? (3)

Muscles, Tendons, and Ligaments

Which two types of cells perform in bone remodeling?

Osteoblasts and Osteoclasts

3 Parts of the Microscopic Anatomy of Compact Bone

Osteon (Haversian system), Central (Haversian) canal, and Perforating (Volkmann's) canal

How are bone fractures treated?

Reduction and Immobilization

What is the name of the condition where the spine bends abnormally to the side (laterally)?

Scoliosis

Name 3 Abnormal Spinal Curvatures

Scoliosis, Kyphosis and Lordosis

What are Perforating (Sharpey's) Fibers?

Secure periosteum to underlying bone

What is Diaphysis?

Shaft and composed of compact bone

What are the three parts of the Axial Skeleton?

Skull, Vertebral Column, and Bony Thorax

Describe Spongy Bone

Small needle-like pieces of bone, has open spaces

What are the two types of cartilaginous joints?

Synchondroses (immobile) and Symphyes (slightly movable, example: pubic symphysis, intervetebral joints)

(T/F) 8-9 Year Olds: Their skull is near adult size and proportion.

TRUE

(T/F) Primary curvatures are present from birth

TRUE

Bone markings are also passages for nerves and blood vessels. (T/F)

TRUE

The clavicle (collarbone) and scapula (shoulder blade) compose what?

The Pectoral (Shoulder) Girdle

What are joints?

They are articulations of bones.

Where are the primary curvatures located? (spinal curvatures)

Thoracic and Sacral regions

Synarthroses

immovable joints