Download Human Anatomy, First Edition McKinley&O'Loughlin

Human Anatomy,
First Edition
McKinley & O'Loughlin
Chapter 6 Lecture Outline:
Cartilage and Bone
Connective Tissue
1
Skeletal System
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Composed of dynamic living tissues.
Interacts with all of the other organ systems .
Continually rebuilds and remodels itself.
Includes the bones of the skeleton as well as
cartilage, ligaments, and other connective tissues
that stabilize or connect the bones.
Supports our weight.
Interacts with muscles to produce movements.
Permits us to sit, stand, walk, and run.
6-2
3 Major Functions of Cartilage
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Supporting soft tissues.
Providing a gliding surface at
articulations (joints), where two bones
meet.
Providing a model for the formation of
most of the bones in the body.
6-3
Types of Cartilage
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The human body has three types of
cartilage:
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Hyaline cartilage
Fibrocartilage
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Elastic cartilage
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Functions of Bone
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Bones are composed of all tissue types.
Their primary component is osseous connective
tissue.
The matrix is sturdy and rigid due to calcification, or
mineralization.
6-7
Support and Protection
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Bones provide structural support and
serve as a framework for the entire
body.
Bones also protect many delicate
tissues and organs from injury and
trauma.
6-8
Movement
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Muscles attached to the bones of the skeleton
contract and exert a pull on the skeleton,
which then functions as a series of levers.
6-9
Hemopoiesis
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Blood cell production in red bone
marrow, which is located in some
spongy bone.
Red bone marrow contains stem cells
that form all of the blood cell types.
6-10
Storage of Mineral and Energy
Reserves
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More than 90% of the body’s reserves of the minerals
calcium and phosphate are stored and released by
bone.
 Calcium is an essential mineral for such body
functions as muscle contraction, blood clotting,
and nerve impulse transmission.
 Phosphate is needed for ATP utilization, among
other things.
6-11
Classification of Bone by
Shape
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Long
Short
Flat
Irregular
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Four Types of Bone Cells
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Osteoprogenitor cells
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Osteoblasts
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produce new bone, and onceosteoblasts become
entrapped in the matrix they produce and secrete, they
differentiate into osteocytes
Osteocytes
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stem cells derived from mesenchyme which produce
other stem cells and osteoblasts
mature bone cells
Osteoclasts
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are involved in bone resorption
6-14
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Flat Bones Within the Skull
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Composed of two layers of compact
bone, with a region of spongy bone
sandwiched between them.
Both layers of compact bone are
covered by periosteum
6-16
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Ossification
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Begins in the embryo and continues as the skeleton
grows during childhood and adolescence.
Even after the adult bones have formed, ossification
continues.
By the eighth through twelfth weeks of embryonic
development, the skeleton begins forming from either
thickened condensations of mesenchyme or a hyaline
cartilage model of bone.
These models are replaced by hard bone.
6-22
Intramembranous Ossification
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Produces the flat bones of the skull, some of
the facial bones (zygomatic bone, maxilla),
the mandible (lower jaw), and the central
part of the clavicle (collarbone).
It begins when mesenchyme becomes
thickened and condensed with a dense supply
of blood capillaries, and continues in several
steps.
6-23
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Endochondral Ossification
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Begins with a hyaline cartilage model
and produces most of the other bones
of the skeleton, including the bones of
the upper and lower limbs, the pelvis,
the vertebrae, and the ends of the
clavicle.
6-26
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Epiphyseal Line Formation
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Endochondral ossification of a long
bone occurs in progressive stages.
Bone growth is complete when each
epiphyseal plate has ossified and the
epiphyseal line has formed.
Depending on the bone, epiphyseal
plate ossification occurs between the
ages of 10 and 25 years.
6-29
Bone Remodeling
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Although adult bone size has been
reached, the bone continues to reshape
itself throughout a person’s lifetime in a
constant process of bone resorption and
deposition.
6-30
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Bone Growth
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Interstitial growth occurs in the
epiphyseal plate as chondrocytes
undergo mitosis
Appositional growth occurs within the
periosteum.
6-32
Bone Remodeling
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The continual deposition of new bone
tissue and the removal (resorption) of
old bone tissue.
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helps maintain calcium and phosphate
levels in body fluids, and can be stimulated
by stress on a bone
occurs at both the periosteal and endosteal
surfaces of a bone
6-33
Blood Supply and Innervation
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Bone is highly vascularized, especially in
regions containing red bone marrow.
Blood vessels enter bones from the
periosteum.
The nutrient artery and the nutrient vein
supply the diaphysis of a long bone.
6-34
Effects of Hormones
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Control and regulate growth patterns in bone
by altering the rates of both osteoblast and
osteoclast activity.
Growth hormone affects bone growth by
stimulating the formation of another
hormone, somatomedin which is produced by
the liver.
Somatomedin directly stimulates growth of
cartilage in the epiphyseal plate.
6-35
Effects of Hormones
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Thyroid hormone stimulates bone
growth.
Growth hormone and thyroid hormone
regulate and maintain normal activity at
the epiphyseal plates until puberty.
Calcitonin inhibits osteoclast activity.
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