mesenchymal tissue Prepared by: Ms. BR Tsauses Anatomical Pathology - - PowerPoint PPT Presentation

Connective tissue & mesenchymal tissue

Prepared by: Ms. BR Tsauses Anatomical Pathology 2A (ANP611S) April 2020

Learning objectives

• Understand connective and mesenchymal tissues in order to describe

and apply appropriate staining techniques in Histology.

Pre-learning Quiz

• Please take the pre-learning quiz before proceeding with the

presentation.

Introduction

• Connective tissue (CT) is of the four tissue types
• Derived fom latin word connectere meaning to bind.
• Is to connect together and provide support

Introduction cont…

• During embryonic development: ectoderm + endoderm =

mesoderm

• This germ layer is known as mesenchymal
• Mesos means middle
• Enchyma means infusion

Connective tissue

CT are divided into:

• 1. Connective tissue proper (dense, areolar, regular,adipose regular

and reticular

• 2. Cartilage (hyaline elastic, fibrocartilage)
• 3. Bone( spongy or cancellous and dense or cortical)
• 4. Blood
• 5. Blood-forming (hematopoietic)

Connective tissue cell types

• Fibroblast
• Mast cells
• Histocytes
• Adipose cells
• Reticulor cells
• Osteoblast and osteocytes
• Chondroblast and chondrocytes
• Blood cells and blood forming cells

Intercellular substance

• Intercellular substance (ICS) is composed of both amorphous(sulfated

and non sulfated mucopolysaccharides) and formed elements (collagen, reticular fibers and elastic fibers)

• The nature of these substance varies according its function (hard or

dense or soft.)

• Classified into: formed or fibrous type

: gel or amorphous type

Formed or fibrous intercellular substances

Collagenenic fibers

• Most common ICS found in large quantities in most sites
• Appear as individual fibers as in loose areolar tissues e. g tendon
• Collagenic fibers do not branch
• Collagen types: Type (i) up to (vi)

Reticular fibers

• Provide bulk of supporting network of more cellular organs e. g

spleen, lymph nodes, liver.

• To support individual cell within the tissue.

Elastic fibers

• Elastic fibers are associated with respiratory system, circulatory

system and integumentary system

• Oxytalan fibers
• Elaunin fibers
• Lack structure or functional significance.

Basement membrane

• Found throughout the body as resilient matrix separating connective

tissue from epithelial

• Support epithelial cells
• Support epithelial cells lining blood vessels etc
• Divided into three zones or layers:
• lamina- rara (or lamina lucida)
• lamina densa (basal lamina)
• lamina reticularis

Connective tissue

Connective Tissue cont.

Connective tissue cont (examples)…

Connective tissue cont…

Connective tissue…

References

• 1. John D. Bancroft, Christopher Layton and S.Kim Suvarna,

(2013),Bancroft’s Theory and Practice of Histological Techniques,7thEdition, Elsevier, China

• 2. J.A.Kiernan,(2015)Histological and Histochemical Methods,

5thEdition, Scion, UK