No bones about it! - d3jc3ahdjad7x7.cloudfront.net · No bones about it! ... Parts of the skeletal system Bones (skeleton) ... Movement due to attached skeletal muscles
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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
12
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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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
34
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)
36
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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