Anatomy & Physiology I - Exam 1

What are the 5 components of the skeletal system?

Bone tissue, cartilage, blood, dense connective tissue, nervous tissue

How many named bones are in the skeleton?

206

The axial skeleton consists of

Skull, vertebral column, rib cage (thoracic cage)

The appendicular skeleton consists of

Pectoral girdle, pelvic girdle, upper and lower limbs

Bone shapes

Flat, irregular, short, long, sutural (wormian), sesamoid (round)

Flat bones

Ribs, shoulder bones, some skull bones

Irregular bones

Many facial bones, spinal/pelvic vertebrae

Short bones

Wrist and ankle bones

Long bones

Arm, forearm, thigh, leg, palms, soles, fingers, toes

Sutural (wormian) bones

Between flat skull bones

Sesamoid (round) bones

Inside tendons near joints in the knees, hands, and feet

Structures of bones

Dominated by osseous (bony tissue)

Bone structure contains

Nervous tissue, cartilage, fibrous connective tissue

Compact bone

Dense outer layer; solid; contains central space and marrow cavity; layer lining endosteum filled by soft marrow

Spongy bone

Needle-like pieces called trabeculae; porous

Diaphysis

Connected to epiphysis; walls of compact or dense bone

Diaphysis forms a tube with hollow what?

Medullary cavity

All bones are covered by what?

Superficial periosteum

Bony processes

Where ligaments and tendons can attach

Bone markings

Depressions, projections, openings, where ligaments, muscles, tendons attach, or may occur at joint surfaces (7 types)

Fissures

Narrow, slit like openings

Fossae

Deeper depression; articular surface

Foramina

Oval or round opening through the bones

Meatuses

Passageways that resemble canals

Grooves

Shallow depressions

Sinuses

Air filled cavities

Notches

Indentations at edges of structures

Bone projections

Allow for the passage of nerves and blood vessels, and where muscles and ligaments attach OR help to form joints

Crests

Narrow, prominent ridges

Spines

Pointed, sharp, slender

Epicondyles

Raised areas on or above condyles

Trochanter

Large, blunt (only on femurs)

Lines

Narrow ridges, not as prominent

Tubercles

Small, rounded

Processes

Bony prominences

Tuberosities

Large, rounded; may be rough

Condyles

Rounded, articular

Facets

Smooth, almost flat, articular

Heads

Expansions on narrow necks

Rami

Arm-like bars

Microscopic anatomy of bone cells

Includes five different types

Osteogenic cells

Active stem cells that may differentiate into osteoblasts or bone lining cells

Osteoblasts

Produce bone matrix; related to osteoprogenitor cells and osteocytes

Osteocytes

Mature osteoblasts in the bone matrix

Bone lining cells

Help maintain bone matrix

Osteoclasts

Multinucleated bone cells, also known as osteophages

Osteon or haversian system (compact bone)

Structural unit of compact bone, cylinder parallel to long axis of bone, contains hollow tubes of bone matrix called lamellae

Lamellae

Collagen fibers in adjacent rings run in different directions

Lacunae

Small cavities containing osteocytes

Canaliculi

Hair-like canals that connect lacunae to each other and the central canal

Chemical composition of bone

Contains organic components and inorganic components

What are the inorganic components of bone?

Hydroxyapatites or mineral salts; 65% of bone by mass

In embryos, what leads to the formation of the skeleton?

Ossification and osteogenesis

What leads to the development of long bones?

Endochondral ossification

Functions of bones

Hemopoiesis, movement, support and protection, fat and mineral storage, hormone production

What is hemopoiesis?

The process by which the body produces blood cells and blood plasma

Bone homeostasis

Bone self-repair, 5% to 7% of bone mass recycled every week

What is the most common disorder of bone homeostasis?

Bone fracture

Compact bone is replaced how often?

Every 10 years

Spongy bone is replaced how often?

Every 3 to 4 years

Bone fracture is classified by what?

Positioning, completeness of fracture, penetration of skin by bones

Nondisplaced fracture

Bone ends stay in normal position

Displaced fracture

Bone ends are out of alignment

Complete fracture

Bone is broken completely through

Incomplete fracture

Bone not broken completely through

Open or compound fracture

Bone penetrates skin

Closed or simple fracture

Bone does not penetrate skin

Comminuted fracture

Bone breaks into many fragments

Skull fracture

A break in one or more of the bones that form the cranium, usually because of blunt force trauma

Wolff's Law

Bones grow or remodel in response to forces or demands placed upon them

Rickets

Bowing of a child's legs, deformities of pelvis, rib cage, skull; due to a deficiency of calcium or vitamin D

Osteomalacia

Poor bone mineralization in adults may cause abnormal gait, decreased muscle tone, weakness, and immobility

Osteoporosis

Bone resorption is quicker than bone deposition; spongy bone of the spine is most vulnerable, most common in postmenopausal women

Skull contains how many bones?

22

The only movable bone in the skull is the?

Mandible

The facial skeleton contains how many bones?

14

How many vertebrae form the spine?

26

The spinal vertebrae are separated by what?

Intervertebral discs of cushioning cartilage, connected by ligaments

What does the vertebral column support?

Head and trunk

How many cervical vertebrae are there?

7

What is the vertebra that supports the head?

Atlas (C1)

What is the vertebra that comes after atlas?

Axis (C2)

How many thoracic vertebrae are there?

12

There are how many lumbar vertebrae?

5

The largest vertebrae are the?

Lumbar because they support more weight

Sacrum

Triangular structure of 5 fused vertebrae

Coccyx (tailbone)

Lowest part of vertebral column; composed of 4 fused vertebrae

Intervertebral Disc Herniation

Common in lumbar spine; outward bulging causes pressure on spinal cord

Kyphosis

Exaggeration of dorsal curvature in the thoracic region (often due to osteoporosis)

Lordosis

Inward lumbar curvature

Scoliosis

Abnormal lateral curvature, usually thoracic

Thorax contains how many ribs?

12

How many ribs are there in total?

24 (12 pairs for each thoracic vertebrae)

True ribs

The first seven pairs of ribs are attached directly to the sternum

False ribs

Last 5 pairs, do not attach to sternum directly

Floating ribs

Ribs 11 and 12 do not attach to the sternum

Ribs attach to the sternum by way of?

Costal cartilage

Pectoral girdle (shoulder girdle)

Clavicle and scapula on each side, connects the upper limb bones to the axial skeleton

Upper limbs

Includes arm bones, forearms, and hand bones

Upper limbs function

Provide muscle attachments, function to move limb parts