Chapter 6 - Skeletal System Flashcards
What are the five functions of the skeletal system?
- Support- bone is hard and rigid; cartilage is flexible yet strong
- Protection- skull around brain, ribs, sternum
- Movement- muscles pull on bones via tendons, ligaments allow restricted movement
- Storage- calcium and potassium are stored and released
- hematopoesis- bone marrow gives rise to blood cells
What are the cell types of tendons and ligaments?
______________
What are the three types of cartilage associated with the skeletal system?
- Hyaline cartilage
- Fibrocartilage
- Elastic cartilage
What is the precursor to bone?
Hyaline cartilage
What is articular cartilage?
Hyaline cartilage at the ends of bone— cartilage only seen on growth plates in youth
What are the two types of cartilage growth?
- Appositional Growth- chondroblasts in perichindrium lay down new extracellular matrix and adds new cells
- Interstitial Growth- chondrocytes in matrix divide and add matrix
What do chondroblasts and chondrocytes do?
Chondroblasts produce matrix; chondrocytes maintain matrix; live in lacunae
What is the perichondrium?
A double layer of connective tissue around cartilage- avascular
What is the composition of bone matrix?
~ 35% organic and 65% inorganic
What is the main organic and inorganic component of bone?
Collagen and proteoglycans (organic portion (1/3) )
Hydroxyapatite (calcium phosphate) (inorganic/mineral component)
What is hydroxyapatite?
Ca10(PO4)6(OH)2, the primary inorganic component of bone
What happens when mineral is removed from bone?
Bones become soft and pliable (vitamin d deficiency- rickets in children or osteomalacia)
What happens when collagen is removed from bone?
Bones become brittle (vitamin c deficiency - scurvy)
What is Osteogenesis Imperfecta?
A disorder characterized by brittle bones- not making enough collagen - bones shatter
Blue sclera
What is Fibrodysplasia Ossificans Progressiva (FOP)?
A disorder causing fibrous connective tissue or muscles to turn into bone
What is Osteopetrosis?
Also known as ‘Marble Bone Disease’, characterized by dense bones
What do osteoblasts do?
Produce collagen and proteoglycans for the matrix. Also secrete calcium and phosphate for mineral portion
What is ossification?
Conversion of a substrate into bone matrix
Collagen produced by ER and Golgi- precursors of hydroxyapatite stored in vesicles and released by exocytosis
What do osteocytes do?
Mature osteoblasts— Maintain the matrix and are less active than osteoblasts
What do osteoclasts do?
Break down matrix using enzymes (degrade organic) and acid (degrade inorganic)
Where are osteoclasts found?
In both the periosteum and endosteum
What are osteochondral progenitor cells?
Stem cells that can become cartilage or bone cells
What are the two types of bone?
- Woven Bone - formed during fetal development and fracture repair
- Lamellar Bone
What is the difference between woven and lamellar bone?
Woven has collagen fibers in many directions and is immature bone; lamellar has fibers in flat sheets and is mature bone