Week 3 Histology Flashcards
What is this a slide of? What type of collagen is found in hyaline cartilage?
This is a slide of a traecha and type II collagen is found in hyaline cartilage
What are chondrocytes? And what is their relationship to their lacunae?
Chondrocytes occur singly or in groups, and are large spherical or ovoid cells with a centrally located nucleus and one or more nucleoli. The cartilage cells are found within lacunae. During life the lacunae are completely filled by the chondrocytes, however, shrinkage of the cells away from the walls of the lacunae occurs during tissue processing. The vacuolation of the cells is also an artifact of processing due to poor preservation of fat and glycogen. Toward the center of the cartilage mass, chondrocytes are found in groups, each group representing the offspring of a single parent chondrocyte. Such a group is known as an isogenous group or cell nest. Chondrocytes are responsible for the secretion and production of collagen fibers and proteoglycans.
During embryonic development, what two types of growth occur in cartilage?
Chondrogenesis refers to cartilage formation by mesenchymal cells and has two types of growth:
Appositional Growth results from a chondrogenic layer that continually divides to form cartilage cells and deposit ECM on the cells periphery. This growth increases the thickness of the cartilage from the outside.
Interstitial Growth – cartilage grows in length by continued cell divisions while secreting more ECM. This growth occurs within the cartilage.
What is this a slide of this?
It is the epiglottis
Where in the body is elastic cartilage found?
Elastic cartilage is found in the external ear, walls of the external acoustic meatus, the auditory (Eustachian) tube, and the epiglottis of the larynx.
What kinds of connective tissue fibers are found in elastic cartilage?
Type II collagen fibrils and elastic fibers
What is this a slide of? Where are the chondrocytes?
Fibrocartilage is found in the intervertebral disks and where ligaments and tendons are attached to bone. Examine the section of the intervertebral disk. Note that not all of the intervertebral disk is fibrocartilage. The fibrocartilage occurs between areas of dense connective tissue and hyaline cartilage; the two tend to merge together.
Chondrocytes are located in rows usually few in number and smaller compared to hyaline and elastic cartilage and are widely separated from each other. They differ from fibroblasts in their ovoid or spherical shape and their position in lacunae. Be sure to compare to tendon in longitudinal section stained with H&E.
Where in the body is fibrocartilage found?
in all intervertebral disks and where tendons/ligaments connect to bone
How will you distinguish fibrocartilage from hyaline and elastic cartilage?
There is no perichondrium present, the collagenous fibers are parallel or interwoven and are usually in a herringbone pattern. Also, the chondrocytes seem to be more spaced out in a regular pattern.
What is this an image of and what is circled?
Examine the dried ground compact bone slide. This tissue has been cut thinly enough to transmit light. Bone matrix appears white and spaces within bone in which air is entrapped appear dark. Compact bone is composed mostly of mineralized interstitial substance (bone matrix) deposited in lamellae (3 to 7mm thick)
Haversian canals (which contained CT, nerves and blood vessels) are cut in cross-section and surrounded by concentric layers or lamellae of bone. The combined canal system is known as a Haversian system or osteon and consists of lamellae surrounding a centrally located Haversian canal.
What are angular fragments of lamellar bone?
interstitial lamelle
The limits of the Haversian systems are demarcated by refractile lines known as?
Cement lines
Cross-connections or anastomoses between central or Haversian canals, or Haversian systems and the periosteum, are present and known as?
Volkmann canals
How is an osteoclast distinguished from a megakaryocyte?
osteoclasts have multiple nucleases
Megakaryocytes have multiple lobed nuclease
What are the functions of the megakaryocyte and osteoclast?
The megakaryocyte is the source of platelets within the bone. Osteoclasts work where sections of bone is being removed, and rest on tissue where bone reabsorption is actively taking place. Megakaryocyte have multi-lobed nuclei while osteoclasts have multiple nuclei.
What are each of the arrows pointing to?
Green - Volkman’s Canal
Red - Haversians Canals or Osteon
Blue - Canaliculi
Yellow - interstitial lamellae
Yellow - Lacunae with osteocytes
Green - Cement lines
Blue - Haversian canal
Brown - lamellae
What is this a picture of?
Megakaryocyte
What is this a picture of?
Osteoclast
What is this a picture of?
Osteoblasts
What is this a picture of?
Periosteum
What is the little hand on?
Endosteum
