Lec 6: Bones and Skeletal Tissues

• 2 Components of the Skeletal System

  Bones,

  Joints (cartilage, tendons, & ligaments)

  
• What is the human skeleton initially made up of?

  Cartilage,

  Fibrous membranes

  (bone soon replaces these early supporters)

  
• Where are the few cartilages that remain in adults found?


  Mainly in regions where flexible skeletal tissue is needed

  
• How does skeletal cartilage spring back to original shape?

  The high water content allows it to spring back to its original shape after being compressed.

  
• Skeletal cartilage lacks what?

  Blood vessels & nerves

  
• What membrane surrounds skeletal cartilage?

  Perichondrium,

  it acts like a girdle to resist outward expansion when cartilage is compressed

  
• Perichondrium


  a dense irregular connective tissue membrane

  
• 3 basic types of Skeletal Cartilage:

  Hyaline cartilage,

  Elastic cartilage,

  Fibrocartilage

  
• hyaline cartilage function


  Provides firm support with some flexibility

  
• Hyaline Cartilage Location


  Forms most of theembryonic skeleton;Covers theends of most bonesat moveable joints,Connectsribsto sternum,Nose,trachea, andlarynx

  
• 4 types of skeletal Hyaline cartilages

  Articular Cartilage

  Costal Cartilage,

  Respiratory Cartilage,

  Nasal Cartilage

  
• Articular Cartilage (hyaline)


  Covers the ends of bones at moveable joints to decrease friction

  
• Costal Cartilage (hyaline)


  Connect ribs to the sternum,

  Found in thoracic cage

  
• Respiratory cartilages (hyaline)


  Form the skeleton of the larynx (voice box),

  Reinforce other respiratory passageways such as the Trachea

  
• Nasal Cartilage (Hyaline)


  supports external nose

  
• Elastic Cartilage


  Contains elastic fibers so better equipped to handle repeated bending,

  Located in external ears & epiglottis

  
• Fibrocartilage


  Highly compressible with great tensile strength,

  Found in sites subjected to both pressure & stretch

  
• Fibrocartilage location


  Pad like cartilages of the knee (menisci),Discs between vertebrae (intervertebral discs)

  
• Functions of Bones


  Support,

  Protection,

  Anchorage,

  Mineral Storage,

  Blood cell formation,

  Triglyceride (fat) storage,

  Hormone production

  
• Calcium is essential for what?

  Muscle Contraction

  Blood Clothing

  Nerve Function
• The most important minerals stored in bones are:

  calcium and phosphorus
• How are bones classified?

  Location & shape

  
• 2 grouped location of skeleton:

  Axial Skeleton,

  Appendicular skeleton

  
• How many bones are in the human body?

  206 bones

  
• Shape of bones:


  Long,

  Short,

  Flat,

  Irregular

  
• Long bones are


  longer than they are wide with shaft + 2 ends,ex) all limb bonesexceptpatella, wrist, & ankle

  
• Short bones are


  Roughly cube shaped,ex) ankle (tarsals) and wrist (carpals) bones

  
• Flat bones are


  Thin, flattened, and usually curved

  ex) sternum, scapulae, ribs, & most skull bones

  
• Irregular bones are


  Complicated shape that doesn't fit into preceding classes,

  ex) vertebrae, hip bones, etc.

  
• Two types of osseous tissue

  Compact bone,

  Spongy bone

  
• Compact bone


  Smooth and solid in appearance

  
• Spongy Bone


  Honeycomb appearing bone

  
• Where is red and yellow bone marrow found?

  spongy bone

  
• Red Bone Marrow


  Responsible for producing blood (blood cell production)

  
• Yellow Bone Marrow


  Stores Fat

  
• Bone Markings


  Projections (bulges),

  ex)Heads, trochanters, spines, etc.

  Depressions and opening

  ex) Fossa, sinuses, foramina, grooves

  
• Projections that are sites of muscle and ligament attachment

  
• Projections that help form joints/ Depressions & openings

  
• Structure of a typical long bone include:

  Diaphysis (shaft),

  Epiphysis (expanded end area),

  Membranes

  
• Diaphysis


  Shaft of bone,

  Forms longitudinal (long) axis,

  Medullary cavity filled with yellow marrow