Download Hole`s Human Anatomy and Physiology

PowerPoint Presentation
to accompany
Hole’s Human Anatomy
and Physiology, 9/e
by
Shier, Butler, and Lewis
Chapter 7
Skeletal System
Bone Classification
• Bones are classified according to shape
• Long bones are long with expanded ends,
Ex: forearm and thigh bone
• Short bones are cube like, Ex: wrist, ankle
• Flat bones are broad and plate like, Ex: ribs,
scapulae, and some skull bones
• Irregular bones vary in shape, Ex: vertebrae
• Sesamoid or round bones are small bones
embedded in tendons, Ex: kneecap (patella)
Parts of Bone
• Epiphysis: end of
the bone which
articulates (forms
a joint) with
another bone.
• The epiphyses
are composed of
spongy bone and
covered with
hyaline cartilage
called articular
cartilage.
Figure 7.2
Parts of Bone
• Diaphysis:
shaft of the
bone between
the epiphyses,
composed of
compact bone
with a
medullary
cavity in the
center.
Parts of Bone
• Periosteum:
fibrous tissue
covering of the
bone.
Compact Bone
• Osteocytes and layers of intercellular material lie
in concentric rings around an osteonic canal.
• This unit is called an osteon or Haversian system.
• Osteonic canals contain blood vessels and nerve
fibers and are interconnected by transverse
perforating (Volkmann’s) canals.
Spongy Bone
• Osteocytes lie within trabeculae, branching
bony plates.
• Nutrients diffuse into canaliculi that lead to
the trabeculae.
Bone Growth and Development
• The skeletal system begins to form during
the first weeks of prenatal development.
• Some bones originate within sheets of
connective tissue (intramembranous bones).
• Some bones begin as models of hyaline
cartilage that are replaced by bone
(endochrondral bones).
Intramembranous Bones
• Broad, flat skull bones are intramembranous
bones.
• During osteogenesis layers of primitive,
connective tissue supplied with blood
vessels appear at the site of future bone.
Intramembranous Bones
• Cells differentiate into osteoblasts (bonebuilding cells) which deposit spongy bone.
• Osteoblasts become osteocytes when
surrounded by bony matrix in lacunae.
Intramembranous Bones
• Connective tissue on the surface of the bone
forms the periosteum.
• Osteoblasts on the inside of the periosteum
deposit compact bone over spongy bone.
• This process is called intramembranous
ossification.
Endochondral Bones
• Hyaline cartilage forms a model of the bone
during embryonic development.
• Cartilage degenerates, periosteum forms.
• Periosteal blood vessels and osteoblasts
invade the bone forming a primary
ossification center in the diaphysis.
• Secondary ossification centers develop in
the epiphyses.
Endochondral Bones
• Osteoblasts form spongy bone in the space
occupied by cartilage.
• Osteoblasts become osteocytes when bony
matrix surrounds them.
Endochondral Bones
• Osteoblasts beneath the periosteum deposit
compact bone around spongy bone.
• A band of cartilage remains between the
diaphysis and epiphyses as the epiphyseal
disk.
Bone Growth
• Growth of long bones occurs along four
layers of cartilage in the epiphyseal disk.
• First Layer: resting cells that do not grow.
• Second Layer: young mitotic cells.
• Third Layer: older cells that enlarge.
• Fourth Layer: dead cells and calcified
intercellular substances.
Bone Homeostasis
• After bone formation, osteoclasts and
osteoblasts continue to remodel the bone.
• Resorption and deposition are regulated to
keep bone mass constant.
Nutrition and Bone Development
• Vitamin D is necessary to absorb calcium in
the small intestine.
• Vitamin D deficiency leads in rickets in
children and osteomalacia in adults.
Nutrition and Bone Development
• Vitamin A is necessary for osteoblast and
osteoclast activity.
• Vitamin C is necessary for collagen
synthesis.
Hormones and Bone
• Growth Hormone (GH) stimulates
epiphyseal cartilage cell division.
• Deficiency of G H: pituitary dwarfism.
Excess GH: pituitary gigantism in children
and acromegaly in adults.
Hormones and Bone
• Thyroid hormone stimulates cartilage
replacement in the epiphyseal disks.
• Sex steroids promote formation of bone
tissue close the epiphyseal disk.
Physical Factors Affecting Bone
• Physical stress stimulates bone growth.
• Weight bearing exercise stimulates bone
tissue to thicken and strengthen
(hypertrophy).
• Lack of exercise leads to bone wasting
(atrophy).
Bone Function
• Bones shape, support, and protect body
structures.
• Bones act as levers to create body
movement with muscles.
• Bones house blood cell producing tissue.
• Bones store inorganic salts.
Support and Protection
• Bones give shape to the head, face, chest,
and limbs.
• Bones of the skull protect structures like the
eyes, ears, and brain.
• Bones of the rib cage and shoulder protect
the heart and lungs.
• Bones of the pelvic girdle protect the
abdominal and reproductive organs.
Body Movement
• When body parts move, bones and muscle
act as levers.
Body Movement
• A lever has
four parts: a
bar, a fulcrum,
an object
moved, a force
to supply
energy.
• There are
three classes
of levers.
Figure 7.13
Body Movement
Body Movement
Body Movement
Figure 7.14
Body Movement
Fracture Repair
• Blood escapes from damaged blood vessels
and forms a hematoma.
• Spongy bone forms in regions near blood
vessels and fibrocartilage forms farther away.
• A bony callus replaces the fibrocartilage.
• Osteoclasts remove excess bony tissue,
restoring new bone much like the original.
Blood Cell Formation
• Blood cell formation (hematologists) occurs
in yolk sac in early development.
• Later it occurs in the liver and spleen.
• In the adult red and white blood cells are
formed in the red bone marrow.
Blood Cell Formation
• Red marrow fills the cavity in the diaphesis
of the long bones in infants. In adults it is
replaced with yellow marrow (fat).
• Adult red marrow is found in spongy bone
of the skull, ribs, sternum, vertebrae, pelvis.
Inorganic Salt Storage
• Salts account for 70% of the bone matrix.
• These salts are mostly calcium phosphate
crystals called hydroxyapatite.
Inorganic Salt Storage
• Parathyroid hormone stimulates osteoclasts
to break down bone when Ca levels are low.
• Calcitonin stimulates osteoblasts to build
bone when Ca levels are high.
• Bone contains Mg, Na, K, and carbonate
ions.
Axial Skeleton
• The skeleton has two divisions: the axial
and the appendicular skeleton.
• The axial skeleton consists bones that
support organs of the head, neck, and trunk.
• Skull :cranium and facial bones.
• Hyoid bone.
• Vertebral column.
• Thoracic cage: ribs and sternum.
Appendicular Skeleton
• The appendicular skeleton consists of the
bones of the limbs and bones that anchor
the limbs to the axial skeleton.
• Pectoral girdle: scapula, clavicle.
• Upper limbs: humerus, radium, ulna,
carpals, metacarpals, phalanges.
• Pelvic girdle: coxal bones.
• Lower limbs: femur, tibia, fibula, patella,
tarsals, metatarsals, phalanges.
Figure 7.17
Figure 7.17
Cranium
•
•
•
•
•
•
Frontal bone: forehead
Parietal bones: top of the skull
Occipital bone: back of the skull
Temporal bones: side of skull, near ears
Sphenoid bone:base of the cranium
Ethmoid bone: roof of the nasal cavity
Figure 7.19
Figure 7.19
Figure 7.21
Figure 7.21
Figure 7.22
Figure 7.22
Facial Skeleton
•
•
•
•
•
•
•
•
Maxillary bones: upper jaw, hard palate
Palatine bones: hard palate, nasal cavity
Zygomatic bones: cheek bones
Lacrimal bones: orbit of the eye
Nasal bones: bridge of the nose
Vomer bone: nasal septum
Nasal conchae:walls of the nasal cavity
Mandible: lower jaw
Figure 7.29
Figure 7.29
Figure 7.29
Infantile Skull
• The skull at birth is not fully developed.
• Fibrous membranes, fontanels, connect the
cranial bones.
• The fontanels allow movement of the bones
to enable the skull to pass through the birth
canal.
• The fontanels close as cranial bones grow.
Figure 7.33
Figure 7.33
Vertebral Column
• Cervical vertebrae: seven vertebrae of the
neck, includes atlas and axis
• Thoracic vertebrae: twelve vertebrae that
articulate with the ribs
• Lumbar vertebrae: five vertebrae that make
up the small of the back
Vertebral Column
• Sacrum: five
vertebrae that
fuse in early
adulthood, part
of the pelvis
• Coccyx: four
small fused
vertebrae
Figure 7.34
Thoracic Cage
• Ribs: twelve pair of ribs attached to each
thoracic vertebrae.
• Seven pairs: true ribs and attach to the
sternum by costal cartilage.
• Two pairs: false ribs that attach to cartilage.
Thoracic Cage
• Two pairs: floating ribs that do not attach to
the sternum or its cartilage.
• Sternum: the manubrium, the body, and the
xyphoid process.
Pectoral Girdle
• Clavicles: collar bones that attach the
sternum to the shoulder anteriorly.
• Scapulae: shoulder blades with two
processes.
• Acromion process: tip of the shoulder.
• Coracoid process: attaches to the clavicle
and provides attachments for muscles.
• Glenoid fossa articulates with the humerus.
Figure 7.42
Upper limb
• Humerus: upper arm bone, articulates with
the glenoid fossa of the scapula
Upper limb
• Radius: thumb side of the forearm,
articulates with the capitulum of the
humerus and the radial notch of the ulna
• Ulna: longer bone of the forearm, olecranon
and coronoid processes articulate with the
humerus
Hand
• Carpal bones: eight small bones of the
wrist.
• Metacarpal bones: five bones, the
framework of the palm.
• Phalanges: finger bones, three in each finger
(proximal, middle, distal phalanx), two in
the thumb.
Figure 7.47
Pelvic Girdle
• Coxal bones: two hips bones composed of
three fused bones.
• Ilium: superior part of the coxal bone.
• Ischium: lowest portion of the coxal bone.
• Pubis: anterior part of the coxal bone. The
two pubic bones joint at the symphysis
pubis.
Figure 7.49
Figure 7.49
Male and Female Pelvis
• Female iliac bones are more flared.
• The female pubic arch angle is greater.
• There is a greater distance between the
ischial spines and tuberosities in the female.
• The sacral curvature is shorter and flatter.
• The differences create a wider pelvic cavity.
Figure 7.51
Lower Limb
• Femur: thigh bone, longest bone
• Patella: kneecap, located in a tendon, femur,
tibia, and patella form the knee joint
• Tibia: shinbone, lateral malleolus forms the
ankle
• Fibula: slender bone lateral to the tibia, not
part of the knee joint
Figure 7.52
Foot
• Tarsal bones: seven small bones in the
ankle. The calcaneus (heel bone) is the
largest, located below the talus.
• Metatarsal bones: elongated bones that form
the arch of the foot.
• Phalanges: each toe has three except the
great tow which has two.
Figure 7.55
Life-Span Changes
• Calcium levels
fall through life
and the skeleton
loses strength.
• Osteoclasts
outnumber
osteoblasts.
Life-Span Changes
• By age 35,
everyone loses
bone mass.
Women lose bone
mass faster
between
menopause and
age seventy.
• Trabecular bone
is lost before
compact bone.