Connective Tissue, Adipose and Cartilage Lecture Notes

Flashcards based on connective tissue, adipose tissue and cartilage lectures.

What are the three main types of connective tissue fibers?

Collagen fibers, Reticular fibers, and Elastic fibers

What is the main component of elastic fibers?

Elastin

What environmental conditions and body needs, can collagen proteins be modified by?

To become rigid, elastic, or strong

What percentage of dry body weight does collagen make up?

30%

What are the main amino acids in collagen synthesis?

Glycine (33.5%), Proline (12%), and Hydroxyproline (10%)

What is the basic unit of collagen?

Tropocollagen

What is tropocollagen made of?

Three polypeptide chains twisted into a triple helix

What is Reticular fibers composed mainly of?

Collagen type III, Glycoproteins, and Proteoglycans

What type of network do Reticular Fibers form?

Supportive network

Where are reticular fibers found?

Smooth muscle, Endoneurium, Epineurium, Perineurium, Hematopoietic organs, Around cells of organs like liver and endocrine glands

What special stain makes Reticular fibers Appear black?

Silver stain (argyrophilic)

What stain turns Reticular Fibers PAS positive?

Periodic acid-Schiff

What deficiency causes scurvy and weak tissues?

Vitamin C

What needs copper to make collagen strong?

Lysyl oxidase

What is the main function of Collagen type I?

Resistance to tension

What is the main function of Collagen type II?

Resistance to pressure

What is the function of Collagen type III?

Structural maintenance in expansible organs

What is the function of Collagen type IV?

Support of delicate structures, filtration

What is the function of Collagen type VII?

Anchors skin epidermal basal lamina to underlying stroma

What are the three types of Elastic Fiber System?

Oxytalan fibers, Elaunin fibers, and Elastic fibers

What is the function of Oxytalan fibers?

Resist pulling forces

What material occupies the center of Elastic fibers?

Elastin

What amino acid composition does Elastin have that is similar to collagen?

Desmosine and Isodesmosine

How more times can elastin be stretched compared to rubber?

5 times more

What does ground substance Fills space between?

Fibers and cells

What are the three main components of Ground Substance?

Glycosaminoglycans (GAGs), Proteoglycans, and Multiadhesive glycoproteins

What molecule does Collagen fibers contain as the main molecule?

Collagen molecules (especially type I collagen)

What molecule does Reticular fibers contain as the main molecule?

Collagen molecules (especially type III collagen)

What molecule does Elastic fibers contain as the main molecule?

Elastin molecules

What is the function of Glycosaminoglycans (GAGs)?

Highly hydrophilic

Examples of Proteoglycans

Aggrecan, Syndecan, Fibroglycan

Examples of Multiadhesive Glycoproteins

Fibronectin, Laminin

What are the components of ECM ?

Fibers (collagen, elastic, reticular),Ground substance (GAGs, proteoglycans, glycoproteins),Fluid

What is the function of Fibronectin?

Helps with cell adhesion and migration

What is the function of Laminin?

Allows cells to attach to basal lamina

What interacts with Collagen in Glycosaminoglycans?

Electrostatic Interaction

Where can Hyaluronic acid be found?

Umbilical cord, synovial fluid, vitreous humor, cartilage

Hyaluronic acid interacts with what collagen?

None

Chondroitin 4-sulfate interacts with what collagen?

High levels of interaction, mainly with collagen type II

Dermatan sulfate interacts with what collagen?

Low levels of interaction, mainly with collagen type I

Heparan sulfate interacts with what collagen?

Intermediate levels of interaction, mainly with collagen types III and IV

What is the role of hydrostatic pressure in fluid movement through connective tissue?

Pushes fluid out of the capillary

What is the role of osmotic pressure in fluid movement through connective tissue?

Pulls fluid back in to the capillary

Connective Tissue Proper major types:

Loose and dense connective tissue

What are the differences of Loose vs Dense Connective Tissue?

Loose connective tissue: Flexible, delicate, well-vascularized, not very stress-resistant. Dense connective tissue: Fewer cells, dominated by collagen fibers, more rigid and stress-resistant, not flexible

Two types of Dense Connective Tissue:

Irregular and egular

What is Elastic Tissue made of?

Thick, parallel elastic fibers

Where is Mucous Tissue found?

Umbilical cord and Dental pulp of young teeth

Main cellular component for Adipose tissue:

Adipocyte (fat cell)

Adipose tissue expands by:

Hypertrophy and Hyperplasia

Functions of Adipose tissue:

Structural support and protective padding for major organs (e.g., kidneys), Thermal insulation - prevents heat loss through the skin and Energy storage - provides long-term energy during fasting

What hormone is responsible for genetic leptin deficiency?

Leptin is made by fat cells

Functions of Adipose Tissue:

Largest energy reserve, Shaping the body, Mechanical cushioning, Secretory role, Fills anatomical spaces and Thermoregulation

Two Types of Adipose Tissue:

Unilocular and Multilocular

Structural Organization of Yellow Fat

Divided into incomplete lobules by connective tissue septa

What does Unilocular Adipose Tissue produces?

Hormones like leptin, which regulates appetite and metabolism

What are the names of Multilocular Adipose Tissue?

Brown adipose tissue (BAT) and Hibernating gland

What the main function for Multilocular Adipose Tissue?

Heat Production (Thermogenesis)

unilocular VS multilocular Adipose Tissue

Lipid Droplet, One large droplet VS Multiple small droplets; Color, Pale yellow or white VS Reddish-brown; Mitochondria, Few, sparse VS Many, rich in UCP-1; Size of Cells, Larger (50-150 μm) VS Smaller; Shape, Spherical/polyhedral VS Polygonal; Presence in Adults, Common VS Rare; Presence in Newborns, Present VS Prominent; Function, Energy storage, hormone secretion VS Heat generation; Capillary Network, Moderate VS Very rich; Innervation, Some sympathetic input VS Direct and dense sympathetic innervation

Main function of Cartilage Tissue:

it allows it to bear mechanical stresses, function as a shock absorber, provide a sliding area for joints, and facilitate bone movement

What are the two Cellular Components of Cartilage Tissue?

Extracellular Matrix (ECM) and Cellular Components

Nutrients are supplied via what in Cartilage Tissue?

Diffusion or synovial fluid

What are the three types of cartilage?

Hyaline cartilage, Elastic cartilage, Fibrocartilage

Perichondrium contains?

Mesenchymal stem cells, Blood vessels, Lymphatics, and Nerves

Most common form of cartilage Is:

Hyaline Cartilage

What is primary madeStructural protein for Hyaline Cartilage

type II collagen

What is essential for cartilage growth and repair?

Perichondrium

Development of Cartilage (Histogenesis), step one:

Mesenchymal precursor cells differentiate into cartilage-forming cells

Two types of cartilage growth:

Interstitial Growth and Appositional Growth

benign vs malignant Cartilage tumors:

Benign tumors: Chondromas; Malignant tumors: Chondrosarcomas

Composition of Elastic Cartilage:

Type II collagen fibers and Elastic fibers (abundant)

Elastic cartilage is found in:

Auricle (external ear), Walls of the external auditory canal, Eustachian tube, Epiglottis, and Some laryngeal cartilages

Does Fibrocartilage contains a distinct perichondrium?

No, This is a key distinguishing feature from hyaline and elastic cartilage

What two structures make each Intervertebral Disks?

Annulus Fibrosus and Nucleus Pulposus

Hyaline Cartilage VS Elastic Cartilage VS Fibrocartilage

Main Collagen Type; Type II VS Type II+ Elastic fibers VS Type I (main), Type II (minor); Elastic Fibers, Absent VS Present VS Absent; Perichondrium, Present (except articular cartilage) VS Present VS Absent; Chondrocyte Arrangement, Single or in isogenous groups VS Similar to hyaline VS Arranged in rows between collagen; Flexibility, Moderate VS High VS Low (rigid and strong); Tensile Strength, Low VS Low VS High; Locations, Joints, ribs, respiratory tract VS Ear, epiglottis, eustachian tube VS Intervertebral disks, pubic symphysis

What is Bone tissue made of?

Bone matrix: intercellular calcified material and Three cell types: Osteocytes, Osteoblasts, and Osteoclasts.

What is located at the surfaces of bone tissue?

Osteoblasts

What does Osteoclasts secrete??

collagenase, promoting localized digestion of collagen and dissolving calcium salt crystals.

What are the functions of Periosteum and Endosteum?

Nutrition of osseous tissue and Continuous supply of new osteoblasts for bone repair and growth.

Two types of Bone based on gross appearance:

Compact and Cancellous

Describe Primary vs Secondary bone?

Primary (Immature or Woven) Bone: First to appear during embryonic development and fracture repair,Temporary and replaced by secondary bone in adults , Characterized by randomly arranged fine collagen fibers and Lower mineral content and more osteocytes than secondary bone. Secondary (Mature or Lamellar) Bone: Found in adults, collagen fibers arranged in organized lamellae

Haversian System (Osteon) consists of:

A central canal (Haversian canal) surrounded by concentric lamellae, Each canal is lined with endosteum and contains: Blood vessels, Nerves, and Loose connective tissue.

How Endochondral Ossification occurs?

Takes place within a hyaline cartilage model of the future bone.

What kind of skeleton stores?

Stores 99% of the body's calcium

What stimulates bone formation?

Sex Hormones (Androgens and Estrogens)

Two type of Joints:

Diarthroses and Synarthroses

Outer capsule of Diarthroses joints consists of?

Outer fibrous layer and Inner synovial membrane (contains fibroblasts and macrophages)