Ch 7 The Skeletal System (Part 1) Flashcards
What is the skeletal system made of?
bones, cartilages, and ligaments
What is cartilage?
lessen friction in joints and allow for expansion of bony frame
What are ligaments?
connect bone to bone at joints
What are tendons?
connect bone to muscle
What are the functions of the bone and their characteristics?
1) Support - holds up the body
2) Protect - soft tissue like brain
3) Movement - by coordinated action of muscle and bone
4) Electrolyte Balance - by storage of calcium and phosphate
5) Acid Base Balance - buffers blood against pH changes by absorbing/releasing alkaline (basic) salts
6) Blood Formation - red bone marrow is major producer of blood cells
What are the classifications by shape and their characteristics?
1) Long - femur, thigh bone, leg, arm
2) Short - carpal, wrist, ankle
3) Flat - parietal bone from roof of skull
4) Irregular - sphenoid bone from skull, vertebrae
What is the long shaft of a bone called?
diaphysis
What are the 2 expanded ends of a bone called?
epiphysis
What does articular cartilage do?
reduces friction
What is the medullary cavity?
shaft of long bone that has a hallow center
What is marrow?
soft connective tissue
What are the 2 membranes?
periosteum and endosteum
What is the periosteum membrane?
- on outside of bone
- glistening white double membrane
- has osteoblasts and osteoclasts
What are osteoblasts?
builders, make bone
What are osteoclasts?
construction, collapse, break down bone
What is the endosteum membrane?
- on inside of bone
- delicate connective tissue
- lines canals in bone
What is a compact bone?
- primarily in diaphysis
- tough, tightly packed, no spaces
What is a spongy bone?
- primarily in ephiphyses
- covered by thin layer of compact bone
- numerous branching bone plates with spaces between
- spaces reduce bone’s weight
What is trabeculae?
the spaces between the branching bone plates
What is an osteon?
structural unit, tiny support pillars
What is a central canal?
central tube with nerves and blood vessels, connect with perforating canals at right angles
What is a perforating canal?
the channel between each central canal to connect them
What is endosteum?
the lining of canals
What are osteocytes?
mature cells in lacunae
What are canaliculi?
connect lacunae with each other and the central canal, allow for passage of nutrients and wastes
What are lamellae?
concentric rings within the osteon
What are the 2 types of bone?
intramembranous and endochondral
What is intramembranous bone?
- forms broad, flat bones of skull
What is the special connective tissue cells?
- Differentiate into osteoblasts > become active > deposit bony matrix around themselves
What is endochondral bone?
- develops from masses of hyaline cartilage
- cartilage acts like a model
What is the bone development?
- hyaline cartilage model forms bone collar
- cavity forms in hyaline cartilage
- periosteal bud invades > spongy bone
- medullary cavity forms (spongy bone broken down)
- epiphysis ossify > only growth plates remain as cartilage > site of future long bone growth
T or F: Bone is not static.
True
What are the 2 steps in remodeling?
1) bone deposit - new bone continually laid down by osteoblasts
2) bone resorption - old bone continually broken down by osteoclasts, mostly done to get calcium
What are the triggers of bone remodeling?
hormonal (blood calcium levels) and mechanical (break or bruise)
What is calcium homeostasis?
- Skeletons body’s major reservoir of calcium
- Body maintains Ca2t ion level within marrow units
- Osteoporosis
What is osteoporosis?
worn out bone not replaced with new bone fast enough, or too much existing bone is reabsorbed, or both
What are the body’s 2 calcium reservoirs?
1) a large pool which is in a form not readily exchanged with blood
2) exchangeable calcium which is easily released into blood when blood calcium levels drop
What are the normal ion values?
Calcium > 10mg / 100mL
Phosphorus > 4mg / 100mL
What happens when blood calcium is high?
thyroid releases calcitonin
- reduces calcium reabsorption by kidneys > more calcium is excreted in urine
- increases calcium deposit in bone
What happens when blood calcium is low?
parathyroid releases parathyroid hormone
- stimulates release of calcium by bone
- stimulates calcium reabsorption by kidney and with vitamin D increases calcium uptake in intestines
What is nondisplaced vs. displaced fracture?
ends in normal position or not?
What is complete vs. incomplete fracture?
bone broken through or not?
What is open (compound) vs. closed (simple) fracture?
skin broken or not?
What is a greenstick fracture?
usually seen in children, bone is fractured only on one side
What is a spiral fracture?
break is caused by a twisting force, difficult to treat, common causes: skiing, football, soccer, in children - may be a sign of abuse
What is a compression fracture?
the bone is crushed, causing the broken bone to be wider or flatter in appearance
What is the healing of fractures?
- hematoma formation (blood clot)
- fibrocartilages callus formation
- bony callus formation
- bone remodeling
What is the skeleton?
- greek word meaning “dried up body” or “mummy”
- accounts for 20% of body mass which includes bones, cartilages, joints, ligaments
What does the axial skeleton contain?
skull, hyoid, vertebral column, sacrum, coccyx (tailbone), and thoracic cage
What does the appendicular skeleton contain?
pectoral girdle, upper limb, pelvic girdle, and lower limb
What is a pectoral girdle?
scapula and clavicle
What is a girdle?
ring of tissue
What is the skull?
- 22 bones > 8 cranial and 14 facial
- most are flat bones
- all connected by suture lines except movable mandible (lower jaw)
- brain occupies cranial cavity > all bones that enclose it are called “cranial vault”
What is the cranium?
- encloses and protects brain
- attachment point for muscles of massification (chewing) and head movement
- has sinuses
What are sinuses?
- air filled spaces
- mucous membrane lining
- reduce skull weight
- increases resonance of voice (echo)
What are sutures?
an immovable joint of the skull (the line between bones)
What is the frontal bone?
- supraorbital foramen
- 2 frontal sinuses
What is the supraorbital foramen?
blood vessels and nerves > tissues of forehead
What are frontal sinuses?
- above the eyes
- lighten skull
What are parietal bones?
- behind frontal bones
- forms sides and roof of cranium
- fused at sagittal suture
- meet frontal bone at coronal suture
What is the occipital bone?
- joins parietal at lambdoidal suture
- forms back of skull and base of cranium
What is foramen magnum?
large hole on base for passage of spinal cord from brain
What are occipital condyles?
- rounded knobs on either side of the foramen magnum that articulate with 1st vertebrae (the atlas)
- holds up the most important part of the body and helps nod head yes
What is external occipital protuberance?
knob on back of skull, muscle attachment
What are temporal bones?
- joins parietal bone at squamosal suture
What is external acoustic meatus?
leads to inner ear
What is mandibular fossa?
articulate with condyles of the mandible
What is the mastoid process?
attachment for muscles of neck
What is the styloid process?
attachment for muscles of tongue
What is the zygomatic process?
part of cheekbone
What is a sphenoid bone?
- cornerstone of skull
- forms base of cranium, sides of skull, sides and base of orbits of eye
- 2 sphenoidal sinuses
What is a sella turcica?
- “horses saddle”
- depression for pituitary gland
What makes up an ethmoid bone?
- cribriform plate
- crista galli
- perpendicular plate
- conchae
- ethmoidal sinuses
What is the cribriform plate in an ethmoid bone?
roof of nasal cavities, has olfactory foramina for olfactory nerves
What is crista galli in an ethmoid bone?
“rooster’s comb”, dura mater (brain covering) attaches here to help secure the brain
What is a perpendicular plate?
forms top half of nasal septum
What is a conchae?
project into nasal cavities to swirl air before it enters respiratory tract
What is the infantile skull?
- allows for some compression as baby passes through birth canal
- skull bones thinner and more flexible than in an adult > fewer fractures during falls + room for brain growth
What are fotanels?
membranous areas where ossification is not complete, soft spots
What is craniosynostosis?
- premature closure of cranial sutures
- limits growth of skull if left untreated
- may cause mental disabilities
- can be surgically repaired
What are facial bones?
- there are 14 bones
- unpaired are mandible (lower jaw) and vomer
- paired are maxillary (fused upper jaw), zygomatic (cheekbones), nasal, lacrimal, palatine, and inferior nasal conchae
What is the nasal cavity?
- bone + hyaline cartilage
- roof of nasal cavity = cribriform plate of ethmoid
- nasal septum = left vs right
- paranasal sinuses = lighten skull
What is a hyoid bone?
- not really part of the skull
- only bone of body with no direct articulation, which means it does not touch another bone
- anchored by ligaments to styloid process
- attaches to neck muscles; helps raise/lower larynx in speech
