Cartilage and Bone

Question 1

Epithelia Tissue

Answer 1

cells which cover free surfaces or form the secretory cells in glands

(skin = stratified squamous)

Question 2

Muscle Tissue

Answer 2

long thin cells which shorten and cause movement

skeletal, cardiac, smooth (large nuclei, no fibers)

Question 3

Nerve Tissue

Answer 3

cells with long processes which send impulses around the body

(neurons are the cells that actually transmit the electrical signals, neuroglia are the supporting cells of the neural tissue)

Question 4

Connective Tissue

Answer 4

Everything else

Varied in structure and function

large number of extracellular fibers (composed of protein collagen)

connective tissue cells secrete all the extracellular matrix components (including collagen)

ex: skin -> faschia, ligament, tendon, fat, bone, blood

Question 5

Specialized connective tissues

Answer 5

blood

adipose

cartilage

bone

Question 6

blood

Answer 6

has a fluid extracellular matrix

Question 7

adipose tissue

Answer 7

lots of cells that store fat

Question 8

bone

Answer 8

tissue that consists of cells embredded in a mineralized, rigid extracellular matrix

vascular and is constantly undergoing turnover and renewal

Question 9

Functions of the Skeletal System

Answer 9

structural support - to withstand the forces of gravity and allow upright posture

locomotion - bones and cartilages anchor muscles and act as levers in producing movement

protection - of delicate organs

mineral storage - bones are a resevoir of calcium which is necessry for many metabolic functions in the body. Calcium must be maintained at precise levels and is added to or removed from bones as needed

Blood formation - occurs in bone marrow

Question 10

Hyaline Cartilage

Answer 10

look for: lacuna (thing in middle) -> cartilage -> matrix with no fibers -> hylaine cartilage (crystal clean)

Semi-rigid tissue consists of cells (chondrocytes) embedded in a rubbery extracellular matrix

Condrocytes are typical protein-secreting cells and secrete the extracellular matrix that surrounds them. They often are poorly preserved in histological preparations and shrink so that they leave an empty space in the matrix

Examples: nose, costal cartilage, trachea

Question 11

Proteoglycans of cartilage

Answer 11

large, space-filling molecules

highly negatively carged and tightly bind many water molecules

Question 12

Perichondrium

Answer 12

Layer of dense irregular connective tissue that surrounds the cartilage of developing bone

this layer contains cells which can become new chondrocytes when a cartilage grows

Question 13

Interstitial Growth

Answer 13

chondrocytes within the cartilage divide and secrete new matrix. The cartilage slowly deforms to accomodate the new matrix. This type of growth occurs mainly in the fetus and children

(cartilage grows in length)

Question 14

Appositional growth

Answer 14

cells in the perichondrium become chondrocytes and make new cartilage matrix at the surface of the cartilage. This is the main type of growth in adults, but occurs at a very slow rate

(cartilage grows in thickness)

Growth in width of a bone may occur at any time by conversion of cells in the periosteum to osteoblasts

Question 15

Cartilage

(and aging changes)

Answer 15

avascular - metabolically inactive

nutrition and waste removal occurs by diffusion

this means there is very little turnover of its componenets and has a very poor capacity for repair

aging changes - some cartilages acquaire calcium phosphate deposits in the matrix in older individuals. This makes them brittle and prone to fracture

Question 16

Elastic Cartilage

Answer 16

similar to hyaline cartilage but has many elastic fibers in matrix (thin)

external ear, epiglottis

thin extracellular fibers

Question 17

Fibrocartilage

Answer 17

similar to hyaline cartilage but has many more collagen fibers (thick)

has characteristics of both cartilage and dense fibrous connective tissue and is stronger than hyaline cartilage

intervertebral discs and pubic symphysis

Question 18

osteoblasts

osteoclasts

osteocytes

Answer 18

• bone forming (secrete bone matrix proteins, mostly collagen)
• bone resorbing, secrete enzymes and acid to dissolve the bone matrix
• maintain bones, osteoblasts that become trapped within the matrix, remain in contact with each other through long processes. Mechanosensors (which detect stresses and strains in their own local ara)

Question 19

intramembranous bone formation

Answer 19

most skull bones form in connective tissues (not really “membranes”)

Question 20

Bone Matrix

Answer 20

contains collagen and other proteins

calcium phosphate, in the form of hydroxyapatite, precipitates in the matrix several hours after the organic components (proteins) have been secreted

mature bone matrix is about 50% organic material and 50% inorganic minerals

Question 21

Primary center of ossification

Answer 21

begins in the center of the shaft of a long bone and then moves gradually toward the ends of the bone

Question 22

Secondary centers of ossification

Answer 22

at the ends of bone

Question 23

Epiphysial plate

Answer 23

Cartilage between the primary center and the secondary center

All growth in length of a long bone occurs in the epiphyseal plates

Converted to bone after puberty

Question 24

Outer Bone

Spongy Bone

Bone Marrow

Answer 24

Outer part of all bones is formed by this solid layer

In center, irregular network of spongy bone

Within the spaces of spongy bone, blood-forming bone marrow

Question 25

Periosteum

Answer 25

Layer of dense irregular connective tissue on the outer surface of a bone. Some osteoblasts are present in this layer

Question 26

Endosteum

Answer 26

lines the marrow cavity of a bone. Conssits of osteoblasts and osteoclasts.

Question 27

Lamellae in compact bone

Answer 27

(lamellae –> layers)

Form concentric rings around blood vessels (osteons)

Question 28

Callus

Answer 28

supports the bone while the fracture is healing

Question 29

Parathyroid hormone

Answer 29

removes mineral from bone

Question 30

Calcitonin (from thyroid gland)

Answer 30

causes mineral deposition in bone

Question 31

Growth hormone

Answer 31

pituitory gland

stimulates growth of the epiphyseal plate cartilage

Question 32

Estrogen

Answer 32

prevents osteoporoissi in post menopausal women