Anatomy: week 3 Skeletal System
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Anatomy: week 3 Skeletal System
The Skeletal System's functions are:
-Calcium & Phosphorus Storage
-Marrow Cavities- blood cell production
Has 2 Bone Forms:
1. Compact Bone
2. Spongy Bone
-Osteon (ring structures)
-Central canal- parallel to bone
-Lacuna with osteocytes inside them
-Perforating canals- running perpendicular to bone
-Also formed from Lamellae
-Found at the end of the bone- Epiphysis (head of the bone)
-Shaft of the bone is called- Diaphysis
-Red Marrow is where blood cell production occurs
Facts about the bone:
-Prior to 6 weeks, there's no bone- its cartilage. Continues to age 25yr
-Loss of bone mass at age 30
-Bone loss in women can be up to 8% per decade
-Men lose up to 3% per decade
Bone is classified based on shape:
1. Long Bones- longer in length then width
2. Flat Bones- thin; narrow; flat
3. Sutural Bones/Wormian Bones- sutures
4. Irregular Bones- random odd shapes; vertebra
5. Short Bones- cuboidal shaped; make up carpals/tarsal bones, like the wrist/ankle
6. Sesamoid Bone- form where you have joints; small/round; example is the patella-almost everyone has, but also can be found in some in the ankles and wrist
-Found along midline of body
-Make up skull-cranium & facial
-Hyoid Bone- found in the neck (ligament); not connected to any other bone
-Ear ossicles- malleus, incus, stapes--these are the smallest in the body, found in the ear structure
-Remaining 126 bones
-Associated with appendages
-or shoulder girdle; consists of S shaped clavicle, and broad flat scapula-shoulder blade.
- support and protect the lower viscera, including reproductive organs; bones are more massive then Pectoral Girdle due to the stress in weight bearing and locomotion.
Structures in Skull:
-8 Bones make up the cranium
-Has 4 Suture Lines:
1. Sagittal Suture- between parietals
2. Coronal Suture- separates frontal from parietal
3. Lambdoid Suture- separates occip. from parietals
4. Squamous Suture- separates parietal from temperal
-Contacts all other Cranial Bones
Sella Turcica Bone:
-(Saddle- looking) pituitary gland--aka the master gland
-Hard to see
How many bones make up the Eye Socket?
- 7 Bones
How many bones make up the Vertebral Column?
- 26 Bones
-Protects spinal cord
-Broken up into different regions
How many Bones make up the Cervical Region (neck)?
-C1- Atlas; holds up; flat; allows to move head in the "yes" motion (aka. the YES bone)
-C2- Axis; allows head to move in the "no" position (aka. the NO bone)
-C7- vertebra prominens; sticks out; can feel it on the back of neck; ligamentum nuchae
How many Bones make up the Thoracic Region? (main back)
- 12 vertebra
- Rib artiulations
How many Bones make up the Lumbar Region? ( lower back)
How many Bones make up the Sacrum Region?
- 1 single bone-- actually 5 bones fussed together, only counted as 1
How many Bones in the Coccyx?
- 1 bone; actually 3-5 bones fussed together, only counted as 1
How many Rib Bones?
-1 to 7- are true ribs
-8 to 10- are false ribs
-11 to 12- are floating ribs; not connected to sternum
-the Clavicle (collarbone) is the ONLY direct connection between the Axil skeleton, and the Pectoral Girdle.