Integumentary and Skeletal Systems
Test Notes
Skeletal System
 The skeletal system consists of:
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Bones
Cartilage
Tendons
Ligaments
 Bone maintains the shape of the body, protects internal
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organs, is a lever system for muscles to act upon, and is a
site of mineral storage and blood-cell formation.
Cartilage forms a fetal model of bone, covers the ends of
bones, and provides a firm, flexible support.
Tendons attach muscle to bone.
Ligaments attach bone to bone.
To help you remember: LLL, TTT (ligaments are like to
like, tendons are two types)
Skeletal System (Tendons and Ligaments)
 extracellular matrix
of tendons and
ligaments is made
up of primarily
collagen fibers
which makes them
very tough like
ropes or cables.
tendon
ligament
Skeletal System (Cartilage)
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Three types of cartilage:
Hyaline
Elastic
Fibrocartilage
hyaline
elastic
 Hyaline cartilage is most
intimately associated with
bone function and
development
fibrocartilage
Skeletal System (Bone)
 Bone Tissue Types:
 Cancellous (Spongy)
 Compact
cancellous
 Cancellous Bone:
 Located mainly in the
epiphyses of long bones &
the interior of all other
bones.
 Consists of a lacy network
of bone with many small,
marrow-filled spaces.
 Compact Bone:
 Mostly solid matrix and cells.
 Forms most of the diaphysis
of long bones & the thinner
surfaces of all other bones.
compact
Skeletal System (Bone)
 Bone is composed of an organic
matrix (mostly collagen) that
provides flexible strength and an
inorganic matrix (hydroxyapatite)
that provides compressional
strength (weight bearing).
 Hydroxyapatite are calcium
phosphate crystals
 Bone is formed in thin sheets of
extracellular matrix called lamellae
 Compact bone consists of cells
called osteocytes located within
spaces in the matrix called lacunae
Skeletal System (Bone)
 Ossification is the formation of
bone by osteoblasts
 Intramembranous ossification
occurs when osteoblasts begin to
produce bone in connective tissue
membranes (primarily in bones of
the skull)
 Endochondral ossification is the
process that produces most of the
skeleton, occurs when bones
develop from cartilage models,
and occurs when osteoblasts
invade the spaces left by dying
cartilage cells
Skeletal System (Bone)
 Four types of bone, based on their shape:
 Long
 Short
 Flat
 Irregular
Skeletal System (Bone Shapes)
Long bones are longer than they are wide (bones of upper &
lower limbs).
Short bones are approximately as broad as they are long
(bones of ankle & wrist).
Flat bones have a relatively thin flattened shape (some skull
bones, ribs, & sternum).
Irregular bones do not fit in the other shape categories
(vertebrae & facial bones).
Long
bones
Short bones
Flat bones
Irregular bones
BONE STRUCTURE - Long Bone
1.Epiphysis
2.Diaphysis
3.Hyaline (Articular)
Cartilage
4.Periosteum
Skeletal System (Bone)
 a long bone has a diaphysis (shaft)
and an epiphysis (each end)
 the epiphyseal plate (growth plate),
is the site of growth in length of a
long bone, and is found between
each epiphysis and the diaphysis
 a long bone has a medullary cavity
(filled with yellow marrow) in the
diaphysis, has cancellous bone at
the ends (filled with red marrow)
 has an endosteum lining the
medullary cavity
 outer surface covered by a
connective tissue layer- periosteum
Structure of a Long Bone
Figure 6.3a-c
Inside the Long Bone
Medullary Cavity –
hollow chamber filled
with bone marrow
Red Marrow (blood)
Yellow Marrow (fat)
Endosteum
– lining of the
medullary
Types of Bone Tissue
Compact (wall of the diaphysis)
Spongy (cancellous, epiphysis)
Review the Structure of a Long
Bone
Matching quiz at
http://www.mhhe.com/biosci/ap
/holehaap/student/olc2/chap07
matching01.html
Microscopic Structure
MATRIX - where the bone cells live
OSTEOCYTES - mature bone cells, enclosed in
tiny chambers called LACUNAE
OSTEOCYTES form rings (LAMELLAE) around a
HAVERSIAN CANAL which houses blood vessels
Osteocytes are linked by CANALICULI
Haversian Canals are linked by VOLKMAN's
CANALS
Compact Bone
BONE DEVELOPMENT & GROWTH
1. Intramembranous bones – flat, skull
2. Endochondral bones – all other
ALL BONES START AS HYALINE
CARTILAGE, areas graduallly turn to bone
PRIMARY OSSIFICATION CENTER (shaft)
SECONDARY OSSIFICATION CENTER
(ends)
Bone Development & Growth
EPIPHYSEAL
DISK (growth plate) is a
band of cartilage between
the epiphysis and
diaphysis
These areas increase
bone length as the cells
ossify
Cartilage becomes
OSTEOBLASTS become
OSTEOCYTES
RESORPTION
OSTEOCLASTS - dissolve bone tissue to
release minerals, process is called
RESORPTION
Bone Growth
Bone Growth