OCTOBER 30, 2012 STANDARD: SAP2b Explain how the skeletal structures provide support and protection for tissues and function together with the muscular system to make movements possible. EQ: What are the components and function of the skeletal system? WARM-UP: Name the bone 1. 2. 3.
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OCTOBER 30, 2012 STANDARD: SAP2b Explain how the skeletal structures provide support and protection for tissues and function together with the muscular.
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OCTOBER 30, 2012STANDARD: SAP2b Explain how the skeletal structures provide support and protection for tissues and function together with the muscular system to make movements possible.EQ: What are the components and function of the skeletal system?WARM-UP: Name the bone1. 2. 3.
The Skeletal System
Form determines Function
• A perfect illustration of a familiar theme:
*Strong yet light – designed for support and motion.
*Tensile strength – hardest material in the body, yet can resist tension and other forces.
Components of Skeletal System
1. Bone - 2 types: compact and spongy
2. Joints – (articulation) – classified as functionally or structurally
3. Cartilage
4. Ligaments – fibrous cords that bind bones together at joints
Functions of BoneFive Functions:
1) Supports and anchors soft organs
2) Protects soft body organs
3) Moves the body and it parts
Bones are attached to muscle by tendons
4) Stores minerals and fats
Ca & P – transmits messages, contracts muscles and clots blood
5) Produces blood cells (hematopoiesis) within the marrow of certain bones
Two types of bone:
1) Compact bone – dense
2) Spongy bone – open spaces
Types of Bones
Classified according to shape:1) Long – mostly compact bones / arms and
legs2) Short – mostly spongy bone / wrists and
ankles3) Flat – thin and usually curved / spongy bone
between compact bones / skull, ribs, sternum
4) Irregular – do not fit into the other categories / vertebrae
• Which division of the skeletal system includes the skull?
Axial
NOVEMBER 5, 2012
WARM-UP:
EQ: What are the microscopic components of compact bone?
What is the difference between osteocytes, osteoblasts and osteoclasts?
Microscopic Anatomy of Bone
Three types of bone cells:
1. Osteocytes – mature bone cells.
2. Osteoblasts – bone forming cells.
3. Osteoclasts – bone destroying cells.
Microscopic Anatomy of Bone Three types of bone cells
*Osteocytes
*Mature bone cells
*Live in spaces in bone called lacunae.
Osteoblasts
• Bone forming cells
Osteoclasts
• Bone-destroying cells
Compact bone is composed of organized passageways called Haversian Systems
(Osteon).*Osteocytes are formed when osteoblasts
are trapped in bony matrix.
*Lacunae – tiny cavities in the matrix that contain osteocytes.
*Lamellae – concentric circles of lacunae arranged around a central (Haversian) canal.
*Haversian canals – contain blood vessels and nerves.
(you)
(your house)
(your streets)
(main street)
•Haversian system – complex of central canal and rings of matrix.
Canaliculi – radiate outward from Haversian canals forming transport system for nutrients.
This is why bone injuries heal quickly.(side streets)
(neighborhood)
MUSICAL NOTES:
1.Each group will be responsible for taking notes on the following topics:
a. Bone formation (pgs-)b. Bone fractures (pgs-)c. Steps in repairing a fracture (pgs-)
2.The notes will be written on the construction paper at each station.
3.Students will rotate while music is playing and take down the notes located at each station.
Bone Formation
• In embryos, the skeleton is mostly composed of hyaline cartilage.
• In young children, the cartilage is replaced by bone.
Ossification (bone formation)
1. Hyaline cartilage model is covered by bony matrix by osteoblasts.
2. Hyaline cartilage model is digested by osteoclasts, forming a medullary cavity within the newly formed bone.
3. Epiphyseal plates – areas of cartilage at distal ends of long bones where growth takes place.
4) New cartilage is formed at distal ends of epiphyseal plates.
5) Bone replaces cartilage at proximal ends of plates.
This results in lengthening of the bone.This process is controlled by growth hormone in children and sex hormones during puberty.
6) This process ends at adolescence when the epiphyseal plates are covered in bone.
Bone is a dynamic and active tissue!
Bones are constantly remodeled in response to
two factors:1. Calcium levels in the blood – when blood calcium
drops below homeostatic levels, parathyroid hormone is released into the blood, which activates osteoclasts to break down bone and release calcium into the blood.
2. The pull of gravity and muscles on the skeleton – when the skeleton is pulled, bones respond by becoming stronger.
Bone Fractures
• Youth – most fractures result from trauma (accidents).
• Old age – fractures occur as bones become thin and weak.
Fractures
• Closed (Simple) Fracture– Bone breaks clean but does not penetrate the skin
• Open (Compound) Fracture– Broken bone ends penetrate through the skin
• Comminuted-bone breaks into many fragments
• Compression- bone is crushed
Fractures• Depressed- broken bone portion is pressed inward
• Impacted- broken bone ends are forced into each other
• Spiral- ragged break occurs when excessive twisting is applied to bone
• Greenstick- bone breaks incompletely
Fractures
Steps in repair of fracture:
1. Hematoma – blood fills area of break; blood vessels are torn.
2. Fibrocartilage Callous – new capillaries, phagocytes and collagen fibers fill the space forming granulation tissue.
3. Bony Callous – osteoblasts invade area and lay down bone.
4. Remodeling – by osteoclasts to form strong, permanent patch.
Bones of the Human Body
Two divisions of the human skeleton:
1. Axial Skeleton – bones that form the longitudinal axis of the body (head and trunk).
2. Appendicular Skeleton – bones of limbs (arms and legs) and girdles (pectoral and pelvic).
NOVEMBER 8, 2012
WARM-UP:
EQ: What are the bones of the human body?
Answer the following questions:
1. What are the organized passage ways for blood vessels in compact bone called?
Haversian System (Osteon)
2. Osteocytes are __________ bone cells found in _____________.
3. If a bone breaks, _______________ are responsible for laying down new bone.
4. Name 2 types of bone?
Compact and Spongy
mature lacunae
osteoblasts
Axial Skeleton – skull, vertebral column and thorax
A. Skull – cranial and facial bones
1. Cranial bones – 8 large, flat bones
a. Frontal bone – forehead
b. Parietal bones (2) – superior and lateral walls of cranium.
c. Temporal bones (2) – inferior to parietal bones.
d. Occipital bone – floor and back wall of
skull.»Foramen magnum – where spinal
cord connects to brain.
e. Sphenoid bone – floor of cranial cavity.
f. Ethmoid bone – roof of nasal cavity.
2. Facial bones
a. Maxillary bones (2) – fused to form upper jaw.
Paranasal sinuses – 4 pair.– Lighten the skull bones.– Amplify sounds.– Sinusitis – infection resulting from the fact
that lining of throat and nose is continuous.
b. Palatine bones – posterior part of hard
palate.• cleft palate - birth defect that results
when palatine bones fail to fuse during embryonic development.
c. Zygomatic bones – cheekbones.
d. Nasal bones – bridge of nose (tip is cartilage).
e. Mandible – largest and strongest bone in the face.
• TMJ (temperomandibular joints) – join temporal bones to sides of face.
f. Hyoid bone – only bone that does not articulate with another bone – provides a moveable base for the tongue.
Temporomandibular Joint
Fontanels – found in fetal skull; fibrous
membranes connecting cranial bones.
Axial Skeleton – skull, vertebral column, thorax
B. Vertebral Column
1. cervical vertebrae (7) – in neck; small and light.
2. thoracic vertebrae (12) – found in
chest.
3. lumbar vertebrae (5) – largest bones
in lower back.
Intervertebral discs – flexible pads to separate vertebrae.• Cushion vertebrae and absorb shocks.• These become less flexible with age.• Herniated disc – protrudes and presses on spinal
cord and nerves.
Figure 26-12 Osteoporotic vertebral body (right) shortened by compression fractures, compared with a normal vertebral body. Note that the osteoporotic vertebra has a characteristic loss of horizontal trabeculae and thickened vertical trabeculae.
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