Bones Flashcards
What is skeletal cartilage made of?
A variety of cartilage tissue
Characteristics of cartilage
1) Consists primarily of water
2) very resilient (springs back into shape)
3) no nerves or blood vessels
4) surrounded by a layer of dense irregular connective tissue (perichondrium)
5) thickness is limited by the distance that nutrients can diffuse through the matrix to reach cells
What does the Perichondrium do?
1) Helps resist outward expansion when cartilage is compressed
2) Contains blood vessels to nourish cartilage
What are the three types of cartilage?
1) Hyaline
2) Elastic
3) Fibrocartilage
Basic component of all cartilage tissue?
Chondrocytes, enclosed in small cavities (lacunae) within an extracellular matrix containing a jellylike ground substance and fibers
Hyaline Cartilage
-look like frosted glass
-support flexibility and resilience
-most abundant skeletal cartilage
-spherical chondrocytes
What are the different kinds of Hyaline cartilage?
1) Articular cartilage - ends of bones at movable joints
2) Costal - connect ribs to sternum
3) Respiratory - skeleton of larynx, reinforce other respiratory passageways
4) Nasal - support external nose
Elastic Cartilage
-resemble hyaline
-more stretchy elastic fibers aid in repeated bending
-found in external ear and epiglottis
Fibrocartilage
-highly compressible
-great tensile strength
-roughly parallel rows of alternating chondrocytes and thick collagen fibers
-occur in areas subjected to pressure and stretching (menisci, intervertebral discs)
What kind of Matrix does cartilage have?
Flexible, to accommodate mitosis
What are the two ways that cartilage grows?
Appositional and Interstitial growth.
Describe appositional growth
cartilage-forming cells in the surrounding perichondrium secrete new matrix against the external face of the existing cartilage tissue
Describe Interstitial growth
the lacunae-bound chondrocytes divide and secrete new matrix, expanding the cartilage from within
Compare cartilage and bone
*Cartilage
Surrounded by perichondrium
No blood vessels or nerves
Chondrocytes in lacunae
Flexible extracellular matrix (made by chondroblasts)
Appositional growth and interstitial growth
*Bone
Surrounded by periosteum
Blood vessels and nerves throughout
Osteocytes in lacunae
Rigid extracellular matrix (made by osteoblasts)
Appositional growth only
What are the 7 important functions of bone?
1) Support
2) Protection
3) Anchorage
4) Mineral storage (calcium and phosphate)
5) Blood cell transformation (hematopoiesis in bone marrow)
6) Triglyceride (fat) storage (in yellow marrow)
7) Hormone production (osteocalcin)
What does osteocalcin do?
Helps regulate:
1) insulin secretion
2) glucose homeostasis
3) energy expenditure
How many bones in the body?
What are the two groups?
206 named bones
Axial and Appendicular
What bones does the axial skeleton consist of?
Skull, vertebral column, rib cage
These bones protect, support and carry other body parts
What bones does the appendicular skeleton consist of?
upper and lower limbs and girdles (shoulder and hip bones)
These bones help us move and manipulate our environment
What are the classification of bones according to shape?
Long
Short
Flat
Irregular
Describe long bones
-longer than they are wide
-has a shaft plus two ends
-all limb bones except patella, wrist, and ankles
Describe short bones
-roughly cube shaped
-bones of wrist and ankle
-include special type of bone called sesamoid bone (form in a tendon).
What do sesamoid bones do
Some alter the direction of pull of tendon, others reduce friction and modify pressure on tendons to reduce abrasion or tearing.
Flat bones
-thin, flattened, a bit curved
-sternum, scapulae, ribs, most cranial bones
Irregular bones
-complicated shape
-Vertebrae, hip bones
What are the three levels of bone structure?
Gross
Microscopic
Chemical
Dense outer layer of every bone
Compact bone (smooth and solid looking)
What lies internal to compact bone?
Spongy bone (Trabecular bone)