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Name the parts of the skeletal system
bones, joints, cartilages, ligaments, tendons
What are the 2 divisions of the skeletal system?
axial and appendicular
What are the 5 functions of the skeletal system?
Support
Mineral and Triglyceride Storage
Blood Cell Production
Production
Movement
Matrix always contains _____, _____, ____, _____, ____.
Collagen, ground substance, organic molecules, water, and minerals
T/F: proteoglycans make up a large amount of ground substance
True
Proteoglycans attract _______.
Water
Proteoglycans help tissue _____________.
Withstand compression
Tendons are
Muscle to bone
Ligaments are
Bone to bone
Cartilage is
Pad/cushion areas around bone
Cells embedded with cartilage are called _____.
Chondrocytes
What is an osteoblast?
Formation of bone matrix; repair/remodel of bone tissue; produce collagen and proteoglycans (ossification)
What is an osteocyte?
Mature cells that maintain bone matrix
What is an osteoclast?
Cells that break down matrix; bone cells release minerals through osteolysis
Most minerals are in a form of _________.
Calcium phosphate
T/F: mineral component gives weight-bearing strength and is responsible for 3/4 of the weight of the 206 bones in an adult.
False- it's responsible for 2/3 of the weight
Osteocytes are located in spaces called ______, in the _________.
Lacunae; lamellar matrix
Canaliculi is
Small channels that run through the matrix to transport nutrients and remove waste
Compact bone is made of a repeating functional unit called_____.
Osteon
Osteon is made up of concentric circles of ________.
Lamella w/ embedded lacunae; and surrounds the central canal
What are perforating canals?
They allow for blood vessels in the central canals to linked to other vessels
Spongy bone is located @ the ______ of ______ & at the center of other bones.
Epiphysis; long bones
Spongy bone contains _____ interconnecting rods and spaces that contain ______.
Trabiculae; bone marrow
T/F: spongy bone has no osteons
True
Spongy bone is found in locations w/ ______ arriving from many different directions.
Stresses
______ bone is much lighter than ______ bone and reduces weight of skeleton and makes it easier for muscles to move.
Spongy; compact
What are the 4 general shapes of bones?
Long, short, irregular, flat
What is an example of a long bone?
humerus, femur
What is an example of a short bone?
carpals and tarsals
What is an example of a flat bone?
Sternum, cranial bones
What is an example of an irregular bone?
Vertebrae, hip bones, facial bones
Which bone shape has compact bone on the inside w/ hollow central marrow cavity?
Long bone
The epiphysis are wider portions at each end, made up of _____.
Spongy bone
What is an epiphyseal plate?
Site of growth between diaphysis & epiphysis; solidifies into epiphyseal line when full adult height is reached
What is a medullary cavity?
Center of diaphysis; holds red/yellow marrow
What is periosteum?
Membrane around bone's outer surface; contains blood vessels/nerves; tendons/ligaments attach here
What is endosperm?
Membrane that lines the medullary cavity; contains osteoblasts & osteoclasts; involved in growth & repair
Ossification is _______.
Formation of bone by osteoblasts
Intramembranous ossification is_______.
Bone formation occurs within connective tissue membranes
Endochondral ossification is________.
Bone formation that occurs inside hyaline cartilage
Both intramembranous and endochondral bone formation result in ______ and _____ bone.
Compact, spongy
Intramembranous ossification occurs primarily in the ______ when osteoblasts begin to produce bone within connective tissue, known as mesenchyme.
Skull
In intramembranous ossification, osteoblasts line up ________, & begin depositing bone matrix to form trabiculae, which radiate out from centers of the ossification centers.
On the surface
____ or more _________ exist in each flat skull bone and mature skull bones result from fusion of these centers as they enlarge.
2, ossification centers
Intramembranous ossification generally occurs during the ________ of fetal development, & forms the bones of the skull, mandible, and the clavicle.
First 2 months
Endochondral ossification is initially formed is a ________, which is bone formation in the diaphysis of a long bone.
Primary ossification center
__________ is bone formation in the epiphysis.
Secondary ossification center
What are the steps in endochondral ossification?
Chondroblasts build a cartilage model, then become chondrocytes
Cartilage model hardens (calcifies)
Osteoblasts invade calcified cartilage and a primary ossification center forms the diaphysis
Secondary ossification centers form the epiphysis
Original cartilage model is almost completely ossified; remaining cartilage is known as articular cartilage
During bone growth, when cartilage is broken down, the enclosed cartilage is digested away which opens up a _______.
Medullary cavity
Bone replaces _____ through the action of _____.
Cartilage, osteoblasts
Dying chondrocytes are replaced by ______.
Osteoblasts
Bones grow in width by the periosteum & the existing matrix _______.
Appositional growth
What are the requirements for bone growth?
Mineral supply, vitamin D3, hormones, & vitamins A, B, C, D, K
T/F: timing of epiphyseal closure varies from bone-bone and from person-person
True
Bones are remodeled in response to what 2 factors?
Free calcium levels in the blood
Pull of gravity & muscles on the skeleton
Bone remodeling involves:
-removal of existing bones by osteoclasts
-deposition of new bones by osteoblasts
In young adults ____ of the skeletal mass is replaced each year.
1/5
T/F: spongy bone is replaced more often than compact
True
In adults, osteocytes in lacunae continuously _____ & _____ surrounding calcium salts.
Remove, replace
Remodeling bone (esp. spongy bone) is based on:
Appropriate stress & exercise
T/F: muscle is a major storage site for calcium
False- bone is major storage site
Calcium homeostasis is maintained by _____ & ______.
Parathyroid hormone, calcitonin
Parathyroid hormone (increase or decrease) formation/activation of osteoclasts.
Increase
A closed fracture is
Simple; completely internal and only seen on x-rays
An open fracture is
Compound; project through the skin and are at most risk for infection
What are the steps in bone repair?
Broken bone causes bleeding and a fracture hematoma forms
Cells of periosteum/endosteum divide to form a callus(internal/external)
Cartilage model forms first, then osteoblasts enter the callus and form spongy bone; continues for 4-6 weeks after injury
Cancellous bone is slowly remodeled to form compact & cancellous bone
When placed under stress, tissue becomes stronger through ________ & production of collagen fibers.
Increased decomposition of mineral salts
Without mechanical stress, bone does not remodel normally because ________.
Resorption out-spaces bone formation
When there's an absence of mechanical stress, bone weakens through decreased # of ______ and demineralization (loss of bone minerals).
Collagen fibers
What is osteopenia?
Inadequate ossification that naturally occurs in aging as early as 30-40 years old
Osteoblasts _____.
Slow
Osteoclasts _____.
Remain constant
What is osteoporosis?
Loss of bone mass that impairs normal function and can lead to more fractures
T/F: osteoporosis is more severe that osteopenia
True
Osteoporosis is more common in what gender?
Females
For women, osteoporosis usually accelerates after _____ due to decline in circulating estrogen.
Menopause
Foramen is
A large hole/opening
Fossa is
depression
Process is
Projection
Condyle is
Smooth, round ended
Meatus is
Canal-like passageway
Tubercle is
Lump of bone
Axial skeleton forms the _____.
Longitudinal axis of the body
The axial skeleton contains ____ bones.
80
How many bones are in the skull?
22 (8 cranial, 14 facial)
How many bones are in the thoracic cage?
25
How many bones in the vertebral column?
26
The axial skeleton is framework for support/protection of the ____, ____, and ____.
Brain, spinal cord, organs in the ventral body cavity
The axial skeleton provides surface area for muscle attachment such as:
Move head, neck, and trunk
Respiration
Stabilize elements of the appendicular skeleton
The skull houses the ____ & ____.
Brain, sensory organs
What skull bone encloses the brain?
Cranium
The facial bones also include associated bones, _____ and _____.
6 auditory ossicles, 1 hyoid bone
Skull bones are joined together by _____-interlocking immovable joints.
Sutures
The ______ is the only bone attached by a freely moveable joint.
Mandible
The cranium is composed of __ _____ bones.
8 flat
Frontal-
Forehead
Parietal-
Superior/lateral (top sides of the head)
The parietal bone meets midline @ _____ suture.
Saggital
Note
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