Transcript PowerLecture: Chapter 5 - Dutchess Community College

PowerLecture:
Chapter 5
The Skeletal System
Learning Objectives
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List the functions of bone.
Identify human bones by name and
location.
Identify the locations and types of joints.
Characterize several common disorders
associated with the skeletal system.
Impacts/Issues
Creaky Joints
Creaky Joints
Many people currently suffer, or may one
day suffer, from osteoarthritis, in which the
joints between bones become stiff and
painful due to the degeneration of the
cartilage lining.
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Conventional remedies range from pain
relievers to supplements to injections of
steroids.
More unconventional treatments employ
combinations of various botanical extracts.
Creaky Joints

Arthritis is a disorder of the
skeletal system, the
framework of bone, cartilage,
and ligaments on which the
body is built.
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 Should
claims about “medicinal” exotic plant
extracts have to be backed up by
independent scientific testing?


a. Yes, or companies could make any claim
about their product.
b. No, so long as the extract does no harm, let
the buyer decide what to buy.
Section 1
Bone—Mineralized
Connective Tissue
Bone – Mineralized Connective Tissue
Bone is a connective tissue with living cells
(osteocytes) and collagen fibers distributed
throughout a ground substance that is
hardened by calcium salts.
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As bone develops, precursor cells called
osteoblasts secrete collagen fibers and a
ground substance of proteins and
carbohydrates.
Eventually, osteocytes reside within lacunae in
the ground substance, which becomes
mineralized by calcium deposits.
Bone – Mineralized Connective Tissue
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Bones are surrounded by a sturdy membrane
called the periosteum.
There are two kinds of bone tissue.
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Compact bone tissue forms the bone’s shaft
and the outer portion of its two ends.
•
•
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Compact bone forms in thin, circular layers (osteons
or Haversian systems) with small canals at their
centers, which contain blood vessels and nerves.
Osteocytes in the lacunae communicate by way of
canaliculi (little canals).
Spongy bone tissue is located inside the shaft
of long bones.
space
occupied
by living
bone cell
blood vessel
compact bone tissue
spongy bone tissue
osteon
(Haversian system)
spongy bone
tissue
compact
bone
tissue blood vessel
outer layer of dense
connective tissue
Fig. 5.1, p. 88
Animation: Structure of
the Human Thigh Bone
CLICK
TO PLAY
Bone – Mineralized Connective Tissue
A bone develops on a cartilage model.
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Osteoblasts secrete material inside the shaft of
the cartilage model of long bones.
Calcium is deposited; cavities merge to form
the marrow cavity.
Eventually osteoblasts become trapped within
their own secretions and become osteocytes
(mature bone cells).
Bone – Mineralized Connective Tissue
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In growing children, the epiphyses (ends of
bone) are separated from the shaft by an
epiphyseal plate (cartilage), which continues
to grow under the influence of growth hormone
until late adolescence.
Forming bone collar
Cartilage model of future
bone in embryo
When organs form in embryo,
blood vessel invades model;
osteoblasts start producing bone
tissue; marrow cavity forms
Remodeling and growth
continue in newborn;
secondary bone-forming
centers appear at knobby
ends of bone
Mature bone of adult
epiphyses
Stepped Art
Fig. 5.2, p. 89
Animation: How a Long Bone Forms
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TO PLAY
Bone – Mineralized Connective Tissue
Bone tissue is constantly “remodeled.”
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Bone is renewed constantly as minerals are
deposited by osteoblasts and withdrawn by
osteoclasts during the bone remodeling
process.
•
•
Before adulthood, bone turnover is especially
important in increasing the diameter of certain
bones.
Bone turnover helps to maintain calcium levels for
the entire body.
Bone – Mineralized Connective Tissue
• A hormone called PTH causes bone cells to release
enzymes that will dissolve bone tissue and release
calcium to the interstitial fluid and blood; calcitonin
stimulates the reverse.
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Osteoporosis (decreased bone density) is
associated with decreases in osteoblast activity,
sex hormone production, exercise, and calcium
uptake.
a
b
Fig. 5.3, p. 89
Video: Taller and Taller
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TO PLAY
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From ABC News, Human Biology in the Headlines, 2006 DVD.
Section 2
The Skeleton: The
Body’s Bony Framework
The Skeleton:
The Body’s Bony Framework
Bones are the main components of the
human skeletal system.
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There are four types of bones: long (arms),
short (ankle), flat (skull), and irregular
(vertebrae).
Bone marrow fills the cavities of bones.
•
•
In long bones, red marrow is confined to the ends;
yellow marrow fills the shaft portion.
Irregular bones and flat bones are completely filled
with the red bone marrow responsible for blood cell
formation.
The Skeleton:
The Body’s Bony Framework
The skeleton: a preview.
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The 206 bones of a human are arranged in two
major divisions: the axial skeleton and the
appendicular skeleton.
Bones are attached to other bones by
ligaments; bones are connected to muscles by
tendons.
The Skeleton:
The Body’s Bony Framework
Bone functions are vital in maintaining
homeostasis.
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The bones are moved by muscles; thus the
whole body is movable.
The bones support and anchor muscles.
Bones protect vital organs such as the brain
and lungs.
Bone tissue acts as a depository for calcium,
phosphorus, and other ions.
Parts of some bones are sites of blood cell
production.
Table 5.1, p. 90
Section 3
The Axial Skeleton
The Axial Skeleton
The skull protects the brain.
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The skull consists of more than two dozen
bones.
The cranial vault, or brain case, is a grouping
of eight bones.
•
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•
The frontal bone makes up the forehead and
contains the sinuses.
Temporal bones form the lower sides of the cranium
and surround the ear canals.
A sphenoid bone and an ethmoid bone form the
eye socket.
frontal sinus
sphenoid sinus
ethmoid sinus
maxillary sinus
Fig. 5.6c, p. 93
The Axial Skeleton
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Parietal bones form a large part of the skull above
the temporal bones.
An occipital bone forms the back of the skull and
encloses the foramen magnum, which is a
passageway for the spinal cord.
parietal bone
frontal
bone
sphenoid bone
ethmoid bone
temporal
bone
lacrimal bone
zygomatic bone
maxilla
occipital bone
external auditory meatus
(opening of the ear; part of
the temporal bone)
mandible
Fig. 5.6a, p. 92
The Axial Skeleton
 Facial
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bones support and shape the face.
A mandible forms the lower jaw; two maxillary
bones form the upper jaw.
Zygomatic bones form the cheekbones;
lacrimal bones form the inner eye sockets.
Palatine bones make up
the nasal cavity; a vomer
bone forms the nasal
septum.
hard
palate
maxilla
maxilla
palatine
bone
vomer
zygomatic
bone
sphenoid
bone
jugular
foramen
temporal bone
foramen
magnum
parietal bone
occipital
bone
Fig. 5.6b, p. 92
The Axial Skeleton
The vertebral column is the backbone.
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The vertebral column, or backbone, extends
from the base of the skull to the hipbones.
The spinal cord extends through a cavity
formed by the vertebrae.
Humans have 33 vertebrae: 7 cervical, 12
thoracic, and 5 lumbar, plus a sacrum formed
of 5 fused vertebrae and a coccyx of 4 fused
vertebrae.
Fibrocartilaginous intervertebral disks serve
as shock absorbers; they may slip (herniate) or
rupture, leading to pain and immobility.
The Vertebral
Column
Figure 5.7
1
2
3
cervical vertebrae (7)
4
5
6
7
1
2
3
4
5
6
thoracic vertebrae (12)
7
8
9
10
11
12
1
2
lumbar vertebrae (5)
3
4
intervertebral
disks
5
sacrum (5 fused)
coccyx (4 fused)
Fig. 5.7, p. 93
The Axial Skeleton
The ribs and sternum support and help
protect internal organs.
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Ribs (12 pairs) are attached to the vertebrae
dorsally and serve as scaffolding for the upper
body torso.
Most of the ribs are attached to the sternum
ventrally.
Animation: Axial Skeleton
CLICK
TO PLAY
Video: Painful Painkillers
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TO PLAY
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From ABC News, Human Biology in the Headlines, 2006 DVD.
Section 4
The Appendicular
Skeleton
The Appendicular Skeleton
The pectoral girdle and upper limbs provide
flexibility.
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The pectoral girdle includes the bones of, and
is attached to, the shoulder.
•
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The scapula is a large, flat shoulder blade with a
socket for the upper arm bone.
The clavicle (collarbone) connects the scapula to
the sternum.
The Appendicular Skeleton
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Each upper limb includes some 30 separate
bones.
•
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The humerus is the bone of the upper arm.
The radius and ulna extend from the hingelike joint
of the elbow to the wrist.
The carpals form the wrist; the metacarpals form
the palm of the hand, and the phalanges the fingers.
clavicle
humerus
sternum
scapula
ulna
radius
carpals (8)
metacarpals (5)
phalanges (14)
Fig. 5.8, p. 94
The Appendicular Skeleton
 The
pelvic girdle and lower limbs support
body weight.
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The pelvic girdle includes the pelvis and the
legs.
• The pelvis is made up of coxal bones attaching to the
sacrum in the back and forming the pelvic arch in the
front.
• The pelvis is broader in females than males; this is
necessary for childbearing.
The Appendicular Skeleton
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The legs contain the body’s largest bones.
•
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•
The femur is the longest bone, extending from the
pelvis to the knee.
The tibia and fibula form
the lower leg; the kneecap
bone is the patella.
Tarsal bones compose the ankle, metatarsals the
foot, and phalanges the toes.
nutrient canal
into and from
marrow (for
blood vessels
and nerves)
marrow cavity
compact
bone
tissue
spongy
bone
tissue
Fig. 5.4, p. 90
pelvis
sacrum
femur
pubic symphysis
patella
tibia
fibula
metatarsals
phalanges
tarsals
Fig. 5.9, p. 95
Animation: Appendicular Skeleton
CLICK
TO PLAY
Skull bones
cranial bones
Pectoral girdle and upper
limb bones
clavicle
facial bones
Rib cage
sternum
ribs
scapula
humerus
ulna
Vertebral column (backbone)
vertebrae
radius
phalanges
carpals
intervertebral disks
metacarpals
Pelvic girdle and lower
limb bones
pelvic girdle
femur
patella
ligament bridging a
knee joint, here
sliced down through
the middle, side
view.
AXIAL
SKELETON
tibia
fibula
APPENDICULAR
SKELETON
tarsals
metatarsals
phalanges
Fig. 5.5, p. 91
Animation: The Human Skeleton System
CLICK
TO PLAY
Section 5
Joints—Connections
Between Bones
Joints – Connections Between Bones
Synovial joints move freely.
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Synovial joints are the most common type of
joint and move freely; they include the ball-andsocket joints of the hips and the hingelike joints
such as the knee.
These types of joints are stabilized by
ligaments.
A capsule of dense connective tissue surrounds
the bones of the joint and produces synovial
fluid that lubricates the joint.
femur
ligament
posterior cruciate
ligament
meniscus
anterior cruciate
ligament
ligament
ligament (cut)
fibula
tibia
Fig. 5.10a, p. 96
quadriceps
(straightens leg)
biceps femoris
(bends leg)
tendon (to
thigh muscle)
femur
cartilage
knee cap (patella)
ligament
ligament
(to knee cap)
fibula
tibia
Fig. 5.10b, p. 96
© 2007 Thomson Higher Education
flexion at
shoulder
extension at
shoulder
flexion at
knee
extension
at knee
Fig. 5.11a (1), p. 97
© 2007 Thomson Higher Education
hyperextension
Fig. 5.11a (2), p. 97
circumduction
rotation
© 2007 Thomson Higher Education
© 2007 Thomson Higher Education
Fig. 5.11b, p. 97
abduction
adduction
abduction
abduction
adduction
adduction
© 2007 Thomson Higher Education
Fig. 5.11c, p. 97
supination
pronation
© 2007 Thomson Higher Education
Fig. 5.11d, p. 97
© 2007 Thomson Higher Education
gliding movement
between carpals
Fig. 5.11e, p. 97
Joints – Connections Between Bones
Other joints move little or not at all.
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Cartilaginous joints (such as between the
vertebrae) have no gap, but are held together
by cartilage and can move only a little.
Fibrous joints also have no gap between the
bones and hardly move; flat cranial bones are
an example.
intervertebral
disks
In-text Fig., p. 96
Section 6
Disorders of the
Skeleton
Disorders of the Skeleton
Inflammation is a factor in some skeletal
disorders.
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In rheumatoid arthritis, the synovial
membrane becomes inflamed due to immune
system dysfunction, the cartilage degenerates,
and bone is deposited into the joint.
Figure 5.12
Disorders of the Skeleton
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In osteoarthritis, the cartilage at the end of the
bone degenerates.
Tendinitis is the inflammation of tendons and
synovial membranes around joints.
Carpal tunnel syndrome is the result of the
inflammation of the tendons in the space
between a wrist ligament and the carpal bones,
usually aggravated by chronic over use.
Disorders of the Skeleton
Joints also are vulnerable to strains,
sprains, and dislocations.
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A strain results from stretching or twisting a
joint suddenly or too far.
A sprain is a tear of ligaments or tendons.
A dislocation causes two bones to no longer
be in contact.
Disorders of the Skeleton
In factures, bones break.
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A simple fracture is a crack in the bone; not
very serious.
A complete fracture separates the bone into
two pieces, which must be quickly realigned for
proper healing.
A compound fracture is the most serious
because it means there are multiple breaks with
the possibility of bone fragments penetrating
the surrounding tissues.
simple
complete
compound
© 2007 Thomson Higher Education
Fig. 5.13, p. 98
Disorders of the Skeleton
Other bone disorders include genetic
diseases, infections, and cancer.
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Genetic diseases such as osteogenesis
imperfecta can leave bones brittle and easily
broken.
Figure 5.14
Disorders of the Skeleton
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Bacterial and other
infections can spread
from the blood stream to
bone tissue or marrow.
Osteosarcoma, bone
cancer, usually occurs in
long bones.
Figure 5.15
Table 5.2, p. 100