Transcript

1

No bones about it!

Have to reference book OFTEN for pictures &

names of bones for nearly all homework

Should immediately be familiar with major

bone names

Thigh = femur

Arm = humerus

Lower jaw = mandible

Forearm bones = radius (out) & ulna (in)

Heel = calcaneous

Spine = vertebra

Forehead = frontal

Hand = metacarpals

Wrist = carpals

Parts of the skeletal system Bones (skeleton)

Joints

Cartilages

Ligaments

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Separated into two divisions: Axial skeleton skull and bones that support it like vertebral column, ribs, sternum

Vertical axis of body

Appendicular skeleton Limbs and all bones associated with them (hips, fingers, etc)

Support of the body

Protection of soft organs

Movement due to attached skeletal

muscles

Storage of minerals and fats

Ca2+

Blood cell formation

hematopoiesis

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The adult skeleton has 206 bones

Two basic types of bone tissue:

Compact bone

Homogeneous

Spongy bone

Small needle-like

pieces of bone

Many open spaces

Where red blood cell formation occurs

Four types of bone shapes

Long bone Short bone

Flat bone Irregular bone

Figure 5.1

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Long bones

Typically longer than wide

Have a shaft with heads at both ends

Contain mostly compact bone for strength

Examples: Femur, humerus

Short bones

Generally cube-shape

Contain mostly spongy bone

Examples: metacarpals, metatarsals

Flat bones

Thin and flattened

Usually curved

Thin layers of compact bone around a

layer of spongy bone

Examples: Skull, ribs, sternum

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Irregular bones

Irregular shape

Do not fit into other bone classification

categories

Example: Vertebrae and hip

Epiphysis

Ends of the bone

Composed mostly of spongy

bone

Contains red marrow for red

blood cell formation

Diaphysis

Shaft

Composed of compact bone

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Periosteum

Outside covering of the diaphysis

Fibrous connective tissue membrane

Sharpey’s fibers Secure periosteum to

underlying bone

Arteries Supply bone cells with

nutrients

Figure 5.2c

Articular cartilage

Covers the external

surface of the

epiphyses

Made of hyaline

cartilage

Decreases friction at

joint surfaces

Figure 5.2a

Medullary cavity

Cavity of the shaft

Contains yellow

marrow (mostly fat)

in adults

Contains red marrow

(for blood cell

formation) in infants

Figure 5.2a

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Bones do not have smooth surfaces

Surface features of bones

Sites of attachments for muscles, tendons,

and ligaments

Passages for nerves and blood vessels

Categories of bone markings

Projections and processes – grow out from

the bone surface

Depressions or cavities – indentations

Foramen or meatus – (huge or small) holes

Osteon (Haversian System) A unit of bone

Central (Haversian) canal Opening in the center of an

osteon Carries blood vessels and

nerves

Perforating (Volkman’s) canal Canal perpendicular to the central

canal

Carries blood vessels and nerves

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Figure 5.3

Detail of Figure 5.3

Lacunae

Cavities containing bone cells (osteocytes)

Arranged in concentric rings

Lamellae

Rings around the central canal

Sites of lacunae

Canaliculi

Tiny canals

Radiate from the central canal to lacunae

Form a transport system

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Osteon = mansion with many rooms

Haversian canals = major hallway

Volkman canals = smaller hallways

Lamella = wings of mansion

lacunae = rooms in each wing Osteocytes = live/grow in rooms

Canaliculi = doors connecting rooms

In embryos, the skeleton is primarily

hyaline cartilage

During development, much of this

cartilage is replaced by bone (starting

at week 9 in utero)

Cartilage remains in isolated areas

Bridge of the nose

Ears

Parts of ribs

Joints

Epiphyseal plates allow for growth

of long bone during childhood

New cartilage is continuously formed

Older cartilage becomes ossified

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When blood vessels penetrate

cartilage membrane, stimulate it to

become osteoblasts (precursors to

osteocytes)

Cartilage is broken down

Bone replaces cartilage

osteoblast osteocyte

collagen

+ + &

Calcium ions

Bones are remodeled and

lengthened until growth stops

Bones change shape somewhat

Bones grow in width

Figure 5.4a

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Figure 5.4b

Osteocytes

Mature bone cells

Osteoblasts

Bone-forming cells

Osteoclasts

Bone-destroying cells

Break down bone matrix for remodeling and release of calcium

Bone remodeling is a process by both osteoblasts and osteoclasts

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A break in a bone

Types of bone fractures Closed (simple) fracture – break that

does not penetrate the skin

Open (compound) fracture – broken bone penetrates through the skin

Bone fractures are treated by reduction and immobilization Realignment of the bone

Table 5.2

Closed fractures Open fracture

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Hematoma (blood-filled swelling) is

formed

Break is splinted by fibrocartilage to

form a callus

Fibrocartilage callus is replaced by a

bony callus

Bony callus is remodeled to form a

permanent patch of new bone

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Figure 5.5

Forms the longitudinal part of the

body

Divided into three parts

i. Skull

ii. Vertebral column

iii. Bony thorax (ribs and sternum)

Figure 5.6

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Two sets of bones

Cranium

Facial bones

Bones are joined by sutures

Only the mandible is attached by a

freely movable joint

Figure 5.7

Figure 5.11

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Figure 5.8

Figure 5.9

Hollow portions of bones surrounding the

nasal cavity

Lined with mucosal membranes (secrete mucous)

Susceptible to infection since connected to nasal

passage, therefore exposed to air-borne viruses &

bacteria

Figure 5.10

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Functions of paranasal sinuses

Lighten the skull

Give resonance and amplification to voice

Figure 5.10

The only bone that does not

articulate (connect) with

another bone

Serves as a moveable base for

the tongue

Not easily broken due to

location; fractured hyoid

bone is usually indication of

strangulation of an adult

Hyoid bone in adolescents

is primarily cartilage,

therefore flexible Figure 5.12

The fetal skull is large

compared to the

infants total body

length

Fontanelles (soft spot)

– fibrous membranes

connecting the cranial

bones

Allow the brain

to grow

Convert to bone

within 24 months

after birth

Figure 5.13

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Figure 5.13

Vertebrae separated by

intervertebral discs

The spine has a normal

curvature

Each vertebrae is given a

name according to its

location

Cervical (C1-C7)

Thoracic (ribs) (T1-T12)

Lumbar (L1-L5)

Sacral (5 fused)

Coccyx (4 fused)

Figure 5.14

Figure 5.16

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Figure 5.17a–b

Figure 5.17c–d

Scoliosis

Lateral curve

Kyphosis

Outward (hump)

Lordosis

Inward (sway back)

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Forms a cage to protect major organs (lungs,

heart, etc.)

Figure 5.19a

Made-up of three parts

Sternum

Manubrium (top)

Body (middle)

Xiphoid process (bottom)

Ribs

True (1-7); connected to

sternum

False (8-12); not

connected to sternum

Attached (8-10);

connected to rib 7

Floating (11-12); not

connected

Thoracic vertebrae

1

3

2

5

4

6

8

7

10

9

11

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i. Pectoral girdle

ii. Limbs (appendages)

iii. Pelvic girdle

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Composed of two bones

Clavicle – collarbone

Scapula – shoulder blade

These bones allow the upper limb to have

exceptionally free movement

Figure 5.20c–d

Two types of limbs:

Upper (Arms with hands)

Lower (Legs with feet)

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The upper arm is formed

by a single bone

Humerus

Figure 5.21a–b

Figure 5.21c

The forearm has two bones

(remember anatomical position!)

Radius (outer)

Ulna (inner)

Figure 5.22

The hand

Carpals – wrist

Metacarpals – palm

Phalanges – fingers

Distal (tips)

Middle

Proximal (base)

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The thigh has

one bone

Femur

Figure 5.24a–b

The leg has two bones

Tibia (shin)

Fibula

Figure 5.24c

The foot

Tarsals – ankle

Must know:

Talus

calcaneus

Metatarsals – sole

Phalanges – toes

Distal (tip)

Middle

Proximal (base)

Figure 5.25

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Bones of the foot are arranged to form

three strong arches

Two longitudinal

One transverse

Figure 5.26

Coxal (hip) bone

Composed of three pair of fused bones Ilium

Ischium

Pubic bone

The total weight of the upper body rests on the pelvis

Protects several organs Reproductive organs

Urinary bladder

Part of the large intestine

Figure 5.23a

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Figure 5.23b

Figure 5.23c

male male

female female

1. Female inlet is larger/more circular

2. Female pubic arch is > 90° (rounder)

3. Female ischial spines are shorter

Articulations (connections) of

bones

Functions of joints

Hold bones together

Allow for mobility

Ways joints are classified

Functionally – how they work

Structurally – what they look like

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Synarthroses – immovable joints

Ex: skull

Amphiarthroses – slightly moveable

joints

Ex: spinal column/vertebrae

Diarthroses – freely moveable

joints

Ex: shoulder

i.Fibrous joints

Generally immovable -synarthroses

ii.Cartilaginous joints

Immovable or slightly moveable -

synarthroses or amphiarthroses

iii.Synovial joints

Freely moveable - Diarthroses

Bones united by fibrous tissue

Examples

Sutures of skull

Syndesmoses – joints held together by ligaments

Allows more movement than sutures

Ex: distal end of tibia and fibula

Figure 5.27a–b

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Bones connected by cartilage

Examples

Pubic symphysis

Intervertebral joints

Ribcage

Figure 5.27d–e

Articulating

bones are

separated by a

joint cavity

Synovial fluid is

found in the

joint cavity

Shoulder

Knee

Wrist/ankle

Figure 5.24f–h

Articular cartilage (hyaline

cartilage) covers the ends of

bones

Joint surfaces are enclosed by a

fibrous articular capsule

Have a joint cavity filled with

synovial fluid

Ligaments reinforce the joint

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Bursae – flattened fibrous sacs

Lined with synovial membranes

Over 150 in human body

Filled with synovial fluid

Not actually part of the joint

Lubrication

Cushioning

Tendon sheath

Elongated bursa that wraps

around a tendon

Figure 5.28

Figure 5.29a–c

Six types:

Joint Type Location

Plane or gliding Carpals, tarsals

Hinge Knee, elbow

Pivot Neck, forearm

Condyloid or ellipse Wrist, ankle

Saddle Thumb at carpals

Ball-and-socket Shoulder, hip

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Figure 5.29d–f

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Bursitis – inflammation of a bursa usually

caused by a blow or friction

Tendonitis – inflammation of

tendon sheaths

Arthritis – inflammatory or

degenerative diseases of joints

Over 100 different types

Three major ones will be discussed

The most widespread crippling disease

in the United States

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a. Osteoarthritis Most common chronic arthritis

Probably related to normal aging processes

b. Rheumatoid arthritis An autoimmune disease – the immune system attacks the joints

Symptoms begin with bilateral inflammation of certain joints

Often leads to deformities

c. Gouty Arthritis (gout)

Inflammation of joints is caused by a

deposition of urate crystals from the

blood

Can usually be controlled with diet

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Osteoporosis

Bone-thinning disease afflicting 50% women over 65,

20% men over 70

Bones become fragile so minor accidents have

devastating bone fractures

Bones of spine & neck of femur (ball) highly

vulnerable

Spine: Dowager’s hump (kyphosis)

Femur: broken “hip”

Causes:

estrogen deficiency after menopause

Estrogen maintains normal density of bones

Poor diet deficient in calcium, vitamin D

Smoking

Lack of weight-bearing exercises

Bunion

Outward growth

between 1st phalange

and metatarsal joint

(where big toe meets

sole)

Caused by tight-fitting

shoes (high heels) or

injury (ballet dancers)

Usually genetically

predisposed (runs in

families)

Only surgery can

correct it

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Clubfoot

Congenital (at birth) foot deformity affecting 1:1000

Twice as many boys born with it than girls

Linked to smoking and Ecstasy drug use while

pregnant

Bones, joints, muscles, blood vessels all abnormal

Corrected either with series of casts forcing foot to

grow correctly or surgery

Rickets

Softening of bones in

children leading to fractures

and deformity

most frequent childhood

diseases in many developing

countries

Cause: vitamin D deficiency

(lack of sunlight) and/or

lack of adequate calcium in

the diet (usually

malnutrition)

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Leukemia

cancer of blood cells

originating in bone

marrow & affects

lymphatic system

Results in malformed

white blood cells that

are unable to fight

infection

Cause: unknown but

risk factors include

smoking, chemical or

radiation exposure

Treatment: chemotherapy, radiation,

stem cell (bone marrow) transplant

Youth

At birth, the skull bones are incomplete

Bones are joined by fibrous membranes –

fontanelles

Fontanelles are completely replaced with

bone within two years after birth

Puberty

Pelvic girdle broadens in girls as result of

hormones

Entire skeleton gets stronger/robust in boys

Shoulder girdle broadens in boys

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Aging

Vertebral cartilage thins – leads to

decrease in overall height (shrinking)

Menopause in women decreases

estrogen – leads to osteoporosis

Test Wednesday, October 24


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