Histology of Bone and Cartilage

Question 1

What are isogenous groups?

Answer 1

daughter dividing cells in lacunae. These groups are able to form due to the fluidity of ECM

Question 2

Osteocytes in the lacunae secrete this substance around the ground substance…

Answer 2

territorial matrix

Question 3

What’s ECM made of?

Answer 3

collagen fibrils, proteoglycans, glycoproteins, and glycosaminoglycans (HA, chondritan sulfate, keratan sulfate, dermatan, heparin sulfate)

Question 4

What’s function with aggrecan?

Answer 4

aggrecan+hyaluron make up proteoglycan aggregates which aggregates absorb the H2O. When cartilage relaxes, negative proteoglycan aggregates attract the water

Question 5

Describe the features of perichondrium.

Answer 5

vascular supply of the cartilage, between the cartilage and supporting tissue. Outer layer - dense irregular CT that contains fibroblasts and inner layer chondroblasts

Question 6

Histogenesis

Answer 6

mesenchyme >condense>divide>separate(chondrocytes)> isogenous groups (interstitial growth- mitotic division of preexisting chondrocytes) > growth in width (appositional growth) differentiation

Question 7

Collagen type II, glassy appearance, has ground substance made of glycosaminoglycans, proteoglycans, glycoproteins

Answer 7

Hyaline Cartilage

Question 8

Where can you find hyaline cartilage?

Answer 8

Fetal skeleton, sternal ribs, trachea, larynx, nose, epiphyseal plate

Question 9

Where can you find elastic cartilage?

Answer 9

external ear, external auditory meatus, auditory tubes, epiglottis

Question 10

Collagen type 1, no perichondrium

Answer 10

fibrocartilage which makes up intervertebral discs, pubic symphysis, and insertions of tendons

Question 11

What are 6 differences between Bone and cartilage?

Answer 11

bony has hard salts in matrix, nutrients can’t diffuse through, there’s vasculature, lacunae linked by canaliculi, fibrils organized into lamellae, and appositional growth

Question 12

Secretes matrix in woven or organized pattern, type 1 collagen, important for mineralization

Answer 12

Osteoblast

Question 13

Reside in lacunae, with canaliculi, orchestrate bone remodeling

Answer 13

Osteocyte

Question 14

Hematopoietic origin, secretes specialized enzymes that break bone matrix

Answer 14

Osteoclasts

Question 15

What are extracellular matrix inorganic components?

Answer 15

Calcium, phosphorus, hydroxyapatite crystals

Question 16

What are organic compounds of bone extracellular matrix?

Answer 16

type 1 collagen, glycosaminoglycans, proteoglycans, glycoproteins

Question 17

Primary vs Secondary Bone

Answer 17

Primary is woven bone that has random deposition of collagen, low mineral content
Secondary is lamellar collagen fiber parallel arrangement with Haversian (osteon vessel) system

Question 18

Links adjacent Haversian canals

Answer 18

Volkman’s canals

Question 19

How do we get from woven bone to mature Haversian bone?

Answer 19

ossification>woven bone>remodeling>lamellar> Haversian system

Question 20

What happens to our body every 10 years?

Answer 20

our skeleton is regenerated, so new Haversian systems and lamella

Question 21

Intramembranous ossification

Answer 21

mesenchymal cells into osteoblasts, then direct mineralization of matrix secreted from osteoblasts

Question 22

Type of craniostenosis where there’s exophtalmos (bulging eyes) and mutation in fibroblast growth factor receptor

Answer 22

Crouzon Syndrome

Question 23

Type of craniostenosis where there’s skull and midfacial abnormalities, syndactyly, and mutation in fibroblast growth factor receptor 2

Answer 23

Apert Syndrome

Question 24

Enchondral Ossification zones

Answer 24

Resting Zone, Proliferative Zone, Hypertrophic cartilage zone, Calcified cartilage (osteoblasts invade), ossification zone

Question 25

increased bone mass due to abnormal osteoclasts

Answer 25

osteopetrosis

Question 26

Brittle bone disease, abnormal collagen type 1

Answer 26

osteogenesis imperfecta

Question 27

Steps of fracture repair

Answer 27

1. hematoma ad cell death, 2. reabsorption by macrohphages and osteoclasts, 3. Fibrocartilage soft callus formed, 4. Hard callus of woven bone, 5. Stresses on immature bone lead to remodeled lamella bone