Skeletal system

What is an avascular connective tissue that is soft and flexible?

cartilage (Note: found in the ear, nose, larynx, trachea, and joints)

What are the 3 types of cartilage?

1. hyaline (most common, reduces friction and absorbs shock in joints) 2. fibrocartilage 3. elastic

What cells create cartilage?

chondrocytes

From what tissue do chondrocytes originate?

mesenchyme

What is the cartilaginous matrix that chondrocytes secrete made of?

collagen and proteoglycans

What substance is present in tissue as a triple helix with special amino acids hydroxyproline and hydroxylysine, ground substance, and elastin fibers?

collagen

Of what is cartilage primarily composed?

collagen fibers embedded in chondroitin sulfate

How does cartilage receive nutrients?

diffusion

What is cartilage surrounded by?

perichondrium (Note: a dense fibrous connective tissue)

What is the most abundant protein in vertebrates?

collagen

What is living connective tissue that is hard and strong while also elastic and lightweight?

bone

What are the functions of bone?

1. support soft tissue 2. protect internal organs 3. assist in body movement 4. mineral storage 5. blood cell production 6. energy storage (in the form of adipose cells in bone marrow)

What is the most immature form of bone?

woven bone

What is woven bone replaced by?

lamellar bone

What are the types of lamellar bone?

1. spongy 2. compact

What is the basic framework of the skeleton that includes the skull, vertebral column, and rib cage?

axial skeleton

What are the bones of appendages, pectoral and pelvic girdles?

appendicular skeleton

What are immoveable joins that hold together the bones of the skull?

sutures

What are joints that allow bones to move relative to each other?

movable joints

What are bone to bone connectors that strengthen joints?

ligaments (Note: the ACL ligament connects the femur to the tibia and limits rotational knee movement)

What are dense connective tissues that connect muscle to bone and bend skeleton at moveable joints?

tendons

What is the point of attachment for muscle to stationary bone?

origin

What is the point of attachment for muscle to a bone that moves?

insertion

What motion is the straightening of a joint?

extension

What motion is the bending of a joint?

flexion

What is an opening in the bone that allows for the passage of nerves?

foramen (Note: foramen magnum in the skull allows for the passage of the spinal cord)

What bone disorder describes the result of cartilage that covers the bone ends of freely moveable joints beginning to wear away due to aging?

osteoarthritis

What bone disorder is a degenerative disorder with a genetic basis where the cartilage of bone wears away?

rheumatoid arthritis

How does the pelvic structure differ between males and females?

pelvic bones are lighter and wider in females

How does the skull structure differ between males and females?

male skulls have more defined features

Which joint type connects bones without allowing any movement?

fibrous (Note: ex: skull, pelvis, spinous process, and vertebrae)

What joint type describes bones that are attached by cartilage and allow little movement?

cartilaginous (Note: ex: spine and ribs)

Which joint type is the most common type of joint that allows for much more movement as it is filled with synovial fluid that acts as a lubricant?

synovial

Which type of bone cell is part of the mesenchymal stem cell lineage that differentiates into osteoblasts?

osteoprogenitor/osteogenic

Which type of bone cell secretes collagen and organic compounds upon which bone is formed?

osteoblast (Note: incapable of mitosis)

Which type of bone cell differentiates into osteocytes when they release matrix materials around themselves?

osteoblast

Which type of bone cell exchanges nutrients and waste material with the blood?

osteocyte (Note: incapable of mitosis)

Which type of bone cell resorbs (destroy) bone matrix and release minerals back to the blood?

osteoclast

Which type of bone cell have carbonic anhydrase, and develops from WBC's called monocytes?

osteoclast (Note: hematopoietic stem cell lineage)

Which type of bone is highly organized, dense bone that doesn't appear to have cavities from outside?

compact bone

Osteoclasts burrow tunnels that form canals called what?

Haversian canals

What are the concentric rings formed by osteoblasts in compact bone?

lamellae

Osteocytes trapped between the lamellae reside in a space called what?

lacunae (Note: within compact bone)

How do lacunae within compact bone exchange nutrients?

canaliculi

the Haversian canals contain what components?

nerves, blood vessels, and lymph vessels

What are Haversian canals connected by?

Volkmann's canals

The entire system of lamellae + Haversian canals is called what?

osteon

What structure surrounds the medullary cavity?

compact bone

What substance fills the medullary cavity?

yellow bone marrow (adipose tissue)

Which type of bone is less dense bone that consists of an interconnecting lattice of bony spicules called trabeculae?

spongy (cancellous) bone

What substance is spongy bone filled with?

red bone marrow

What is red bone marrow the site of?

hemopoiesis (RBC development)

What kind of bone typically has a long shaft (diaphysis) and two ends?

long bone

What are the two parts of the end of a long bone?

metaphysis and epiphysis

What is the sheet of cartilage is found between the metaphysis and epiphysis called?

epiphyseal plate

What is the location of bone growth?

epiphyseal plate (Note: Bone increases in both length and diameter along the diaphysis as well)

Most of the Ca2+ in the body is stored in bone matrix as what substance?

hydroxyapatite (Note: calcium phosphate mineral)

What is the main calcium compound in bone?

Calcium phosphate (CaHPO4)

How much of the calcium in the body is contained in bones and teeth?

99%

How do osteoblasts respond if stress is put on the bone?

deposit collagen and release calcium phosphate to strengthen the bone (Note: the mineral hydroxyapatite is produced)

Endochondral ossification and Intramembranous ossification occur during which stage in development?

fetal

What type of bone formation describes when cartilage turns into bone (ex: long bones, limbs, fingers, toes)?

Endochondral ossification

What type of bone formation describes when undifferentiated connective tissue is replaced by bone (ex: flat bones, skull, sternum, mandible, clavicles)?

Intramembranous ossification

What membrane is bone surrounded by?

periosteum (Note: highly vascularized. Tendons associated with powerful movements highly integrate with it)

What bone disease causes bone density to decrease, and the bone becomes easier to break and fracture?

osteoporosis

What hormone can help maintain bone density?

estrogen (Note: it can increase a female's risk of blood clots, heart disease, and cancer)

Which practices helps decrease the risk of osteoporosis?

ensure high calcium and vitamin D intake, and regular exercise