Introduction to Bones & Joints Flashcards
Function of the skeleton (3)
- supports body
- gives size and shape
- provides muscle attachment
Contents of skeleton (2) and characteristics.
- Bones - support structures that come in many shapes and sizes
- Joints - between bones that allow movement, many having synovial structures
Biomechanical functions of skeleton (4)
- provides framework - shape and support
- uses joints - allows motion
- provides muscle leverage - mechanical advantage in movement (more efficiency)
- sometimes protect organs - organs are contained within bones
Functional components of skeleton (2); describe what they make up
- Axial - everything along midline: vertebral column, ribcage, skull
- Appendicular - contains forelimb (thoracic) skeleton and hindlimb (pelvic) skeleton
Two parts of axial skeleton (2); describe what they make up
- Cranial: everything in skull
- Post-cranial: everything axial except for skull
What is skeletal tissue derived from?
connective tissue
Types of skeletal tissues (2) - describe each type and give two examples of each.
- Non-mineralized: lack hydroxyapatite
- includes notochord and cartilage - Mineralized: have hydroxyapatite
- includes calcified cartilage and bone
What is the notochord? (3) What does it become in vertebrate adults?
- Rod-like axial support structure
- Source of developmental signaling
- ONLY support system in non-vertebrate chordates
Becomes nucleus pulposus in each vertebral disk
What is cartilage? (1) What is it composed of? (3)
Non-mineralized
- Gel matrix - chondromucoprotein + water
- Collagen or elastic fibers - flexibility
- Chondrocytes (cartilage cells)
What are some characteristics of cartilage? (3)
- No blood supply or innervation
- Flexible - stronger under compression than it is under tension
- Easy to injure and difficult to repair - difficult to get necessary nutrients into chondrocytes; to do so, diffusion through cell matrix must occur
Where does cartilage appear in fetus/juvenile? (1) Where does it appear in adults? (4)
Fetus/juvenile - growth tissue; grows fast because of having surface and interstitial growth
Adults - cartilage in ears, nose, larynx, and joints
What is calcified cartilage? (1) What/where can it be found? (3)
Mineralized - hydroxyapetite in gel matrix; tissue is hard, brittle, and opaque
- Shark vertebrae
- Horse larynx
- Deepest articular cartilage
Characteristics of calcified cartilage (4)
- unorganized microstructure - mineral added between cartilage cells (strengthens)
- stronger than cartilage, BUT repair is more difficult due to hydroxyapetite blocking mineral diffusion
- transitional tissue - towards endochondral ossification
- calcification can be pathogenic!
What type of tissue is bone? (1) What makes it up? (2) Be specific.
Composite tissue
- Organic compounds
- osteoids
- cells - Inorganic components
- hydroxyapatite
- water
What are the osteoids that make up bone made of? (3) How much of the bone weight do they make up?
Type I collagen + bone matrix proteins
- includes osteocalcin
20-25% bone weight
What are the specific cells that make up bone? (3) Describe where each come from.
- osteocytes (most) - bone cells derived from mesenchyme
- osteoblasts - make up bones; derived from mesenchyme
- osteoclasts - break down bones; derived from hematopoietic tissue
How much of bone weight does hydroxyapatite make up?
60-70% of bone weight
What qualities make bone an active, living tissue (4)
- capable of growth which issues at the surface rather than between old bone; bones are remodeled through life!
- can repair injuries
- has blood supply from blood vessels in haversion canals, as well as 5-10% of cardiac output
- has sensory innervation
What are the physiological functions of bone? (4)
- mineral reservoir
- calcium homeostasis
- source of blood cells - bone core contains red marrow where hematopoiesis takes place
- energy source/storage - red marrow is replaced by fat during growth, which forms yellow marrow
What does endochondral ossification (EO) help with? (BROAD)
helps establish hematopoeitic homeostasis
What are the endocrine functions of bone? (1)
release osteocalcin hormone involved in:
1. insulin regulation
2. brain development and function
3. testosterone formation and release
What are the four types of bone shapes?
- long bones
- short bones
- flat bones
- irregular bones
Describe long bones (3). Give examples (1).
- cylindrical
- act as levers
- form from at least three centers of ossification - one diaphysis and two epiphyses
example: limb bones
Describe short bones. (2) Give examples (2).
- no dimension greatly exceeding others
- form from single center of ossification
example: carpal and tarsal bones
Describe flat bones (1). Give examples. (3)
- expanded in two directions
example: many skull bones, scapula, pelvic bones
Give an example of an irregular bone.
cranial elements such as mandible
Describe the external surface of bones. What can the surface be used for?
has numerous elevations (lines, crests/ridges, bumps (tubercles and tuberosities)) and depressions (fossae or grooves (sulci)) - these can be used for attachment sites of various tissues