2nd Lecture on Skeletal Muscle Physiology by Dr. Mudassar Ali Roomi
Skeletal system dr. noura
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Transcript of Skeletal system dr. noura
By
Dr. Noura El Tahawy
http://www.slideshare.net/nmohmed
Functions� Support
� Protection
� Assistance in movement
� Mineral homeostasis
� Blood cell production
� Triglycerides storage
Functions of bones1. Bones form the skeleton which is the framework of the body.
2. The skeleton supports the softer tissues and provides points of attachment
for most skeletal muscles.
3. The skeleton provides mechanical protection for many of the body's
internal organs, reducing risk of injury to them. It forms boundaries of
cranial, thoracic and pelvic cavities. Thus it protects the brain, lungs, heart
etc.
4. Bones permit movement of the body as a whole or part of the body, by
formation of joints, which are moved by muscles.
5. Bone tissues store several minerals, including calcium and phosphorus.
When required, bone releases minerals into the blood facilitating and
maintaining the balance of minerals in the body.
6. Bone contains red bone marrow in which blood cells develop.
7. Bone acts as an important chemical reserve. With advancing age, some
bone marrow changes from red bone marrow to yellow bone marrow
which consists mainly of adipose cells and a few blood cells.
Components � Skull
� Vertebral column
� Auditory ossicles
� Hyoid
� Ribs
� Sternum
Components � Upper limb bones
� Pectoral (shoulder) girdle
� Lower limb bones
� Hip girdle
Types of bones� Long bone
� Short bone
� Flat bone
� Irregular bone
� Seasamoid bone
Types of bones
Long bone � Greater length than width
� Mostly compact bone tissue
� Curved
� Vary in size
� Includes:
Femur Ulna
Tibia Radius
Fibula Phalanges
Humerus
Long bone: Femur
Forms of bone
Short bones� Cube shaped
� Equal lenghth and width
� Mostly spongy, except on surface it is compact
� Includes:
carpal bone (except pisiform)
tarsal bones (except calcaneus)
Flat bones� Thin
� 2 layers of compact surrounding a spongy layer
� Large areas for muscle attachment
� Includes:
Cranial bones
Sternum
Ribs
Scapulae
Irregular bones� Complex shape
� Amount of spongy and compact varies
� Includes:
Vertebrae
Hip bone
Certain facial bones
Calcaneus
Sesamoid bones� Develop in certain muscles tendons
� Protect the tendons from excessive wear
Structure of bone� Diaphysis
� Epiphysis
� Metaphysis
� Articular cartilage
� Periosteum
� Medullary cavity
� Endosteum
Structure of
bone:
Spongy bone tissue
Types of ossification
By
DR. Noura El Tahawy
Bone formation� Intramembranous ossification
(flat bones)
� Endochondral ossification
(long bones)
Bone Growth & Remodeling
Growth
Appositional Growth = widening of bone
� Bone tissue added on surface by osteoblasts of the periosteum
� Medullary cavity maintained by osteoclasts
Lengthening of Bone
� Epiphyseal plates enlarge by chondroblasts
� Matrix calcifies (chondrocytes die and disintegrate)
� Bone tissue replaces cartilage on diaphysis side
Endochondral ossification
Endochondral ossification
� Endochondral ossification is the gradual replacement of
cartilage by bone during development. This is responsible
for formation of most of the skeleton. Osteoblasts arise in
regions of cartilage called ossification centers. They
develop into osteocytes, which are mature bone cells,
embedded in the calcified (hardened) part of the bone
known as the matrix.
Intramembranous ossification
� Intramembranous ossification is the transformation of the
mesenchyme, embryonic cells, into bone. During early
development, the embryo consists of three primary cell layers,
ectoderm on the outside, mesoderm in the middle and
endoderm on the inside. Mesenchyme cells constitute part of
the embryo's mesoderm and develop into connective tissue
such as bone and blood. The bones of the skull derive directly
from mesenchyme cells by intramembranous ossification.
� Most bones arise from a combination of intramembranous
and endochondral ossification. Mesenchyme cells develop
into chondroblasts and increase in number by cell division.
Chondroblasts enlarge and excrete a matrix which hardens due
to presence of inorganic minerals. Chambers form within the
matrix and osteoblasts and blood-forming cells enter these
chambers. The osteoblasts then secret minerals to form the
bone matrix.
Vertebral Column
Vertebral Column
Vertebra
Typical vertebra
�Skull
�Skull
Ribs
Sternum
Upper limb bones� Humerus
� Ulna and radius
� Carpal bones
1- Scaphoid 2- Lunate
3- Triquetrum 4- Pisiform
5- Trapezium 6- Trapezoid
7- Capitate 8- Hamate
� Metacapals
� phalanges
Pectoral girdle� Clavicle
� Scapulae
Bones of the upper
limb
Lower limb bones� Femur � Tibia � Fibula � Tarsal bones
1- Talus 2- Calcaneum3- Navicular 4- Cuboid5- Medial cuniform6- Intermediate cuniform7- Distal cuniform
� Metatarasals� Phalanges
Hip girdle � Hip bone
1- ilium
2- pubis
3- sacrum
Bones of the lower limb
Bones of the lower limb
Bones of the foot
Bones of the foot
Thanks
http://www.slideshare.net/nmohmed