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