Bones and Cartilage

Question 1

Bones and cartilage are what types of tissue? What characterizes this tissue?

Answer 1

Connective tissue

Come from the mesenchyme and has a lot of ECM

Question 2

Perichondrium

Answer 2

Layer of dense connective tissue that surrounds cartilage
Resists outward pressure
Functions in growth and repair of cartilage

Question 3

Characteristics of cartilage

Answer 3

Has perichondrium
Consists primarily of water (mostly in the matrix)
Is a resilient tissue

Question 4

What cell type makes up cartilage?

Answer 4

Chondrocyte

Question 5

Hyaline (glass) cartilage

Answer 5

Appears translucent
Most abundant cartilage
Chondrocytes appear spherical
Collagen unit fibril is the ONLY type of fiber in the matrix
Ground substance holds a large amount of water
Provides support through flexibility

Question 6

Elastic cartilage

Answer 6

Contains many elastic fibers
Yellowish in colour
Able to tolerate repeated bending
Located in epiglottis and cartilage of external ear

Question 7

Fibrocartilage

Answer 7

Resists strong compression and tension
An intermediate between hyaline and elastic
Located in pubic symphysis, menisci of knee, and anulus fibrosus
Does NOT have the perichondrium

Question 8

Lacuna

Answer 8

Cavities in the matrix

Cells reside here

Question 9

Appositional growth

Answer 9

Growth from the outside

Chondroblasts in surrounding perichondrium produce new cartilage

Question 10

Interstitial growth

Answer 10

Growth from within

Chondrocytes within cartilage divide and secrete new matrux

Question 11

5 functions of bone

Answer 11

Support and protection
Movement (skeletal muscles use bones as levers)
Mineral storage (reservoir for important minerals like calcium and phosphate)
Blood cell formation (bone contains red marrow)
Energy metabolism (osteoblasts secrete osteocalcin)

Question 12

Osteocalcin

Answer 12

Secreted by osteoblasts

Can effect tissue sensitivity to insulin and the levels of insulin secretion

Question 13

Organic versus inorganic components of bone tissue

Answer 13

Organic: 35% - cells, fibers, and ground substance - contribute to flexibility and tensile strength
Inorganic: 65% - mineral salts that invade bony matrix - provide exceptional hardness, resist compression

Question 14

Osteogenic cells

Answer 14

Stem cells that differentiate into osteoblasts

Question 15

Osteoblasts

Answer 15

Actively produce and secrete bone matrix

Bone matrix is osteoid

Question 16

Osteocytes

Answer 16

Keep bone matrix healthy

Question 17

Osteoclasts

Answer 17

Found within bone tissue
Responsible for resorption of bone - eat it up - bones are constantly being remodelled
Are derived from a line of white blood cells
Secrete hydrochloric acid and lysosomal enzymes

Question 18

4 types of bones

Answer 18

Long bones
Flat bones
Short bones
Irregular bones

Question 19

Compact bone

Answer 19

Dense outer later

Contains passage ways for blood vessels, lymph vessels, and nerves

Question 20

Spongy (cancellous) bone

Answer 20

Internal network of bone

Question 21

Trabeculae

Answer 21

Little “beams” of bone in spongy bone

Open spaces between trabeculae are filled with marrow

Question 22

Diaphysis

Answer 22

Shaft of long bones

Question 23

Epiphysis

Answer 23

Ends of long bones

Question 24

Periosteum

Answer 24

Outer covering of bone

Helps the bone heal when it is injured

Question 25

Endosteum

Answer 25

Inner lining of bones

Question 26

Medullary cavity

Answer 26

Hollow cavity filled with yellow marrow (fat cells)

Question 27

Diploe

Answer 27

Internal spongy bone of flat bones

Question 28

Structure of flat bones, short bones, and irregular bones

Answer 28

Contain bone marrow but no marrow cavity Have diploe Outer and inner table

Question 29

Osteons

Answer 29

Also called Haversian system Long cylindrical structures Function in support Structurally resemble rings of a tree in cross section Rings are made out of the matrix with collagen fibers in it Contain: lamellae, central canal, perforating canals, and canaliculi

Question 30

Haversian canal

Answer 30

Central canal | Contains nerves and blood vessels

Question 31

Volkmann's canal

Answer 31

Perforating canals | Connect Haversian systems

Question 32

Canaliculi

Answer 32

Tiny canals Way for osteocytes to connect to one another Act like gap junctions Pass nutrients

Question 33

Ossification (definition, and 2 different types)

Answer 33

Bone formation Intramembranous ossification Endochondral ossification

Question 34

Intramembranous ossification

Answer 34

Membrane bones Formed directly from mesenchyme There is a membrane and then ossification begins on the membrane

Question 35

Endochondral ossification

Answer 35

All bones except some bones of the skull and clavicles Bones are modelled in hyaline cartilage Begins forming late in the second month of embryonic development Continues forming until early adulthood

Question 36

In epiphyseal plates of growing bones...

Answer 36

Cartilage is organized for quick, efficient growth Cartilage cells form tall stacks (chondroblasts at the top of stacks divide quickly) Pushes the epiphysis away from the stalk to lengthen entire long bone

Question 37

Growth hormone

Answer 37

Produced by the pituitary gland | Stimulates epiphyseal plates

Question 38

Thyroid hormone

Answer 38

Ensures that the skeleton retains proper proportions

Question 39

Sex hormones

Answer 39

Promote bone growth | Later induces closure of epiphyseal plates

Question 40

Osteoclast

Answer 40

``` Bone-degrading cell Giant cell with many nuclei Crawls along bone surfaces Breaks down bone tissue Secreted concentrated HCl Lysosomal enzymes are released Derived from hematopoietic stem cells ```

Question 41

Osteoporosis

Answer 41

Characterized by low bone mass Bone resorption outpaces bone deposition Occurs most often in women after menopause

Question 42

Osteomalacia

Answer 42

Occurs in adults | Bones are inadequately mineralized

Question 43

Rickets

Answer 43

Bones are weak Vitamin D deficiency Occurs in children Analogous to osteomalacia

Question 44

Osteosarcoma

Answer 44

A form of bone cancer

Question 45

3 places to find fibrocartilages

Answer 45

In the vertebral column Pubic symphysis Knee Everywhere else (except the ear) is hyaline