Lecture 28 Flashcards
Difference between parenchyma and stroma
parenchyma : functional cellular unit (eg : epithelium, nerve, muscle)
Stroma : supporting structure such as connective tissue
What is ECM made up of (3)
Fibers
Ground substance (GAG, proteoglycan, glycoprotein)
Tissue fluid
Function of connective tissue
support, defense, repair, nutrition
What is connective tissue made up of?
Cell & ECM
Is connective tissue supplied by blood vessels and nerve?
YES, it should be so it supplies nutrients to avascular epithelial cells
Difference between permanent and transient cells of connective tissue
permanent : those that stay in connective tissue (fibroblast or macrophage, adipocytes, stem cells, mast cells)
Transient : those that come to connective tissue for an event (basophil eosinophil, neutrophil, lymphocytes, plasma cells)
Different types of fibers in connective tissue (3)
collagen, laminin, elastic
Types of collagen I, II, III, IV
Type I : collagen found in mainly in ECM (heterotrimeric : triple helix)
Type II : cartilage
Type III : Reticular fiber (lymph, liver)
Type IV : basement membrane
2 types of embryonic connective tissue
- Mesenchyme
2. Mucous connective tissue
Features of mucous connective tissue
- found in new borns
- Few cells
- Few fibers
- Abundant ground substances and tissue fluid
Where are mucous connective tissue found?
Umbilical cord (Wharton’s jelly)
Cardiac jelly
Vitreous humor in eye
Which germ layer form almost all connective tissue?
mesoderm
Difference in cell shapes of mesenchyme and mucous connective tissue
mesenchyme : spindle like thin cell shape
mucous : star shaped fibroblasts with sparse reticular fibers
Both have abundant ground substance
Features of loose (areolar) connective tissue
Abundant cells of various types
Few fibers
Abundant ground substance
Characteristics of loose connective tissue (3)
- flexible, not resistant to stress
- rich in blood supply
- fill spaces between other tissues
Location of loose connective tissue (4)
- beneath epithelia surface (for providing nutrients to epithelium) = dermis
- surrounds glands and smallest blood vessels and nerves
Staining for loose connective tissue
Mesentery Verhoeff’s hematoxylin
What is lamina propria?
a thin layer of loose areolar connective tissue part of mucosa
Where is lamina propria found? (3)
lining of respiratory tract
GI tract
Urogenital tract
Features of dense irregular connective tissue
- few cells of single type : fibroblasts - produce fiber and ground substance
- abundant fibers mostly collagen
- little ground substance
Function of irregular connective tissue
No orientation of collagen fibers so it is resistance to stress in all directions
- significant support to organs and structures (organs capsule, periosteum, dermis)
Another name of Irregular dense connective tissue (2)
Reticular layer or deep layer
Feature of dense regular connective tissue
- few cells of single type : fibroblasts: aligned between fiber bundles
- Abundant fibers mostly collagen fibers arranged in a specific orientation
- little ground substance
Where is dense regular connective tissue found? (2)
tendons/ligament
Function of dense regular connective tissue?
tensile strength
What are endotendineum, peritendineum, and epitendineum?
Endotendineum : connective tissue covering around a group of collagen fiber (contain blood vessels for blood supply)
Peritendineum : covering around a group of fascicles
Epitendineum : covering an entire tendon
Function of reticular connective tissue
framework for myeloid (bone marrow), lymphoid organ (lymph node/spleen), liver
Features of reticular connective tissue
reticular cells are modified fibroblasts that its cytoplasmic extensions cover reticular fiber
Which cells produce elastic connective tissue? (2)
fibroblasts and smooth muscle cells
Where are elastic connective tissues found? (4)
elastic arteries, elastic cartilage, vocal ligament, suspensory ligament of penis, elastic aorta
Staining of elastic connective tissue
orcein, resorcin or verhoeff’s
Difference between white and brown adipose tissue
white adipose tissue
- nucleus and cytoplasm to periphery
- one lipid droplet
- function : fat storage
Brown
- central nucleus with many lipid droplets
- function: energy release (rich in mitochondria)
Relationship between aged skin and collagen fiber
Aged skin decreased production of type I and type III collagen fiber and elastic fibers, leading to stretched skin
Difference between hypertrophic and keloid scar
hypertrophic scar : raised than normal, but within original wound boundary,
Keloid scar : in excess of boundary, extending into surrounding tissue
*caused by increased collagen production
How is edema caused?
due to protein deficiency in vessels (eg albumin), tissue fluid increases
is sulfated proteoglycan basophilic or eosinophilic?
basophilic
What are the active and inactive type of fibroblasts and their shapes?
Active = fibroblasts (more branched and larger) Inactive = fibrocytes (no branch, smaller)
What is myofibroblasts?
fibroblasts that have contractile filament
With contractile filament, it can contract the edge of wound and speed up wound healing.
major energy source of adipocyte
triglyceride
main function of brown adipose tissue (2)
heat production, energy production
specialized locations of brown adipose tissue (2)
body neck, abdomen of neonates
From which cell is macrophage derived?
from monocytes. Monocyte migrate to connective tissue and differentiate to macrophages
macrophages in liver
Kupffer cells
Macrophages in brain
microglia
Macrophage in bone
osteoclasts
Morphology of macrophage
irregular cell membrane
- cytoplasmic extensions (pseudopodia)
Roles of macrophage (3)
- phagocytic
- produce cytokines
- antigen presenting cells
Where does mast cell originate from?
originate in bone marrow from precursor cells lacking cytoplasmic granules, then it migrate to connective tissue or lamina propria of mucosa to proliferate and accumulate cytoplasmic granules
Staining mast cell and its granule (2)
Using toluidine blue
- dye color is purple red, but staining is blue (metachromasia)
- Granule staining with PAS
Origin of basophil
bone marrow
Morphology of lymphocyte
small spherical cell with condenced basophilic nucleus and narrow cytoplasm
two types of lymphocyte
B and T cells
What does B-lymphocyte develop into?
plasma cells
Role of plasma cells
synthesize and secrete single class of immunoglobulin (glycoprotein)
Morphology of plasma cell when stained (3)
- basophilic cytoplasm (large RER)
- clockface nucleus- peculiar distribution of chromatin
- negative golgi (slightly brighter close to nucleus since golgi is acidophilic)
Morphology of eosinophils (2)
- eosinophilic granules (red) in cytoplasm
- condensed bilobed nucleus
Role of eosinophils (2)
- kills parasitic worms
- phagocytosis of antibody
What is the first type of collagen synthesized during wound healing?
Reticular fibers
3 developmental stages of elastic fiber
1st : oxytalan
2nd: elaunin
3rd : elastic
is fibrillin of elastic fiber protein or glycoprotein?
glycoprotein
Examples of glycoprotein in ground substance
adhesion molecules - fibronectin, chonderonectin, laminin
integrins - cell surface receptors that bind cells to matrix
