Download Skeletal System Notes

Skeletal System
Bones – the organ of the skeletal system
Long Bones
-Longer than they are wide
-This bone classification reflects the elongated shape
of these bones not the overall size.
Long Bones
Epiphysis – the bone ends
Diaphysis – the shaft that
forms the long axis
of a long bone
Articular Cartilage – hyaline cartilage that coats the
end of bones in synovial joints
Long Bones
Periosteum – a tough, vascular covering of fibrous tissue
on the surface of the bone
Processes – sites for attachment of
ligaments and tendons
Grooves & openings – passageways for
blood vessels and nerves
Depressions – articulate with a process
of another bone
Long Bones
Medullary Cavity
- The center of the diaphysis
- Hollow chamber filled with
yellow bone marrow
Endosteum
-The thin layer of cells that
cover the internal bone structures
Long Bones
Compact Bone
-solid, strong, and resistant
to bending
-makes up wall of diaphysis
Spongy Bone
-bone made up of bars and plates separated by irregular
spaces, which help reduce weight of bone, provide strength,
and decrease compression
-make up most of the epiphysis
Compact Bone
Osteocyte – bone cells
Osteon – long, cylindrical shaped structures that run
parallel to the long axis of the bone
Osteonic Canals – core of the osteon which contains 2 sm
blood vessels that supply nutrients to the
bone cells
*The osteocytes are spider shaped cells that occupy the small
matrix called the lacunae
Compact Bone
Volkmann’s Canal – (perforating canals) extend
longitudinally through bone tissue and connect
the blood and nerve supply to the central canals
and marrow cavity.
Intramembranous Bones
-Flat bones that develop from sheet-like masses of
connective tissue…..exp (bones in skull)
Osteoblasts – bone forming cell that develops around
week 8 of embryonic development
Fontanels. . . Soft spots in the baby's skull where
the membrane has not yet been ossified.
Endochondral Bones
-The formation of long bones …..Fig 7.5 p127
epiphyseal disk/plate – between the primary and
secondary ossification centers
*This cartilaginous disk thickens as a person
grows and new cells divide.
osteoclasts – stimulated to reabsorb bone tissue
Bone Function
1. Support & Protection
2. Body Movement – levers
3. Blood Cell Formation – hematopoiesis: process of blood
cell formation
*red marrow – functions in formation of red and
white blood cells and blood platelets
*hemoglobin – red oxygen carrying pigment
*yellow marrow – functions in fat storage, and is
inactive in blood cell production.
It replaces red marrow with age.
Bone Function
4. Storage of Inorganic Salts
– excess calcium and phosphorus is stored in
intracellular matrix of the bone
Read Osteoporosis in text
Organization Of The Skeleton
I.
Axial Skeleton – bony and cartilaginous bones that
protect and support the organs of the
head, neck, and trunk.
1. Skull
2. Hyoid Bone
3. Vertebral Column
4. Thoracic Cage
Figure 6.1 The Axial Skeleton
• Anterior
view of the
skeleton,
highlighting
components
of the axial
skeleton.
Organization Of The Skeleton
II. Appendicular Skeleton
1. Pectoral Girdle (scapula and clavicle)
2. Upper Limbs (humerus, radius-outside,
ulna-inside, carpals, metacarpals, phalanges)
3. Pelvic Girdle (coxal bones)
4. Lower Limbs (femur, tibia-inside, fibula-outside,
patella, tarsals metatarsals, phalanges)
Skull
Consists of 22 bones held together by sutures
Skull
A. Cranium - surrounds and protects the brain, provides
sites for muscles attachment (8 bones)
1. Frontal bone
2. Parietal bone (2)
3. Occipital bone
4. Temporal bone (2)
5. Sphenoid bone
6. Ethmoid bone
Facial Bones
1.
2.
3.
4.
5.
6.
7.
8.
Maxillae
Palatine
Zygomatic bones
Lacrimal bones
Nasal bones
Vomer
Inferior nasal conchae
Mandible
Figure 6.2 Cranial and Facial Subdivisions of the Skull
• The skull can
be divided
into the
cranial and
the facial
divisions.
Figure 6.2 Cranial and Facial Subdivisions
of the Skull
Sutures
*Immovable joints
*Form boundaries between skull bones
5 Sutures
-Coronal (between frontal and parietal bones)
-Sagittal (between parietal bones)
-Lambdoid (between occipital and parietal bones)
-Squamous (between parietal and temporal bones)
-Frontonasal (between frontal and nasal bones)
Figure 6.3a/b The Adult Skull (posterior/superior)
Infantile Skull
Fontanels – fibrous membranes or soft spots that permit
movement as skull develops and also helps
pass during delivery.
Vertebral Column
-Vertebrae extend from the skull to the pelvis and are
separated by intervertebral disks.
3. Pedicle : 2 short stalks
5. Laminae : 2 plates
6. Spinous process : the laminae fuse together *
4. Transverse process: between the pedicles and *
laminae
2. Transverse foramen :
*
*
*
Cervical Vertebrae
•Bony axis of the neck
•C1-C7
•The smallest and lightest vertebrae
Cervical Vertebrae
Thoracic Vertebrae
•12 Vertebrae
•T1 – T12
•All articulate with ribs
Lumbar Vertebrae
•Large strong bodies to support weight
•L1-L5
•Makes up the small of your back
•Receives the most stress
Lumbar Vertebrae
Sacrum
•A curved, triangular structure, that shapes the posterior
wall of the pelvis
•S1-S5 : fused
Coccyx
•Tailbone, small and triangular
•Normally consists of 4 fused bones (sometimes 3 or 5)
•Besides giving the pelvic organs little support it is almost
useless
Thoracic Cage
-The chest and its bony framework
*Ribs
•True ribs (1-7)
•False ribs (8-12)
•Floating ribs (11-12)
Sternum
1. Manubrium
2. Body
3. Xiphoid process
Pectoral Girdle
-Shoulder girdle: consists of the clavicles, and the scapulas
1. Clavicles – collarbones
2. Scapulae – shoulder blade
a) acromion process – “apex of shoulder”
b) coracoid process – “beak-like”
c) glenoid cavity – “pit-shaped”
Upper Limbs
-humerous, radius, ulna, carpals, metacarpals, phalanges
Humerous
Radius
-outside (lateral bone) of
forearm, or thumb side of the
forearm
-thin at its proximal end and
widened at its distal end
Ulna
-inside (medial bone) of forearm,
or little finger side of forearm
-proximal end is a coronoid process,
olecranon process, and trochlear
notch - grips the humerus like a pliers
Hand
-carpals: (8) wrist
-metacarpals: palm
-phalanges: fingers
-proximal
-middle
-distal
Gliding joints
Synovial joints
Skeletal System
Don’t forget…….
Always wear your…….
HELMET!!!