HMB302 Lab Notes

Topics: Epithelium, Epithelial cells, Collagen Pages: 8 (2199 words) Published: November 25, 2014
Classification of Epithelia

Lines
Examples
Simple squamous
Surfaces involved in passive transport
Alveoli
Endothelium
Loops of Henle
Simple cuboidal epithelia
Surfaces involved in secretion and absorption
Some glands
Ducts
Collecting tubule of kidney
Simple columnar epithelia
Surfaces involved in high rates of secretion and absorption
Protection
Stomach and small intestine where it has microvilli
Collecting tubule of kidney
Fallopian tubes where it is ciliated

Pseudostratified
Usually ciliated with goblet cells
Respiratory tract in large airways, e.g. trachea
Parts of male reproductive system
Stratified cuboidal or columnar
Rare

Stratified squamous nonkeratinized
Surfaces requiring protection from abrasion, pathogens and chemical attack Kept moist by glandular secretion
Lining of mouth
Throat
Esophagus
Rectum
Anus
Vagina
Stratified squamous keratinized
Surfaces requiring protection from abrasion, pathogens and chemical attack Protects against dehydration
Skin – acts as barrier to evaporation
Transitional
Surfaces which must allow stretch and recoil
Round and puffy cells on top when relaxed, flattened cells when stretched Urinary bladder
Ureter

Connective Tissue and Cartilage

Structure and Function
Found in:
Areolar CT
Least specialized – all cell and fibre types
Provides support
Allows independent movement
Provides defence against pathogens
Superficial fascia
Between muscles, BVs, Ns
Around joints
Reticular CT
Delicate thin reticular fibres
Forms stroma (scaffolding) of highly cellular organs on which they arrange their parenchyma (functional cells) Liver, spleen, kidney, lymph nodes, bone marrow, smooth muscle Adipose CT
Adipocytes
With areolar CT
Amount and distribution varies with age, sex, activity level Deep to skin
Behind eyes
Around kidneys
Dense Regular CT
Type I collagen fibres arranged in parallel arrays
Tensile strength in one direction
Tendons
Aponeuroses
Ligaments
Dense Irregular CT
Type I collagen fibres arranged in meshwork sheet
Tensile strength in more than one direction
Reticular layer of dermis
Submucosa of GI tract
Periosteum, perichondrium
Organ and joint capsules
Elastic CT
More elastic fibres  more resiliency
In structures that stretch and recoil
Ligamentum flavum
Supporting transitional epithelium
BVs
Hyaline Cartilage
Most common
Weakest cartilage
Closely packed Type II collagen fibrils in firm gel-like GS
Resists compxn
Provides tough, flexible support
Reduces friction btwn bony surfaces in articulations
Articular cartilage* - no perichondrium
Tracheal rings
Costal cartilage
Nasal cartilage
Immature skeleton
Elastic CT
Like hyaline, but more elastic fibres
Provides greater flexibility and resiliency
Pinna of external ear
Epiglottis
Pharyngotympanic tube
Fibrocartilage
Densely interwoven Type I collagen fibres arranged in perpendicular arrays Intermediate in strength between hyaline and dense regular
Chondrocytes in rows between fibre bundles
Resists compxn and tension
Annulus fibrosis
Pubic symphysis
Intra-articular disks
Tendon and ligament insertions

Laboratory I: Epithelium

Simple Epithelium – single layer of epithelial cells

Simple Squamous Epithelium
Very flattened
Nuclei: round to oval, dark blue, project into lumen of structures Cytoplasm: extremely flattened, thin, indistinct in light microscopy Lines surfaces involved in passive transport
Lines loops of Henle in medulla, and BVs
*Nuclei of cells lining loops of Henle are more rounded and less flattened then nuclei of endothelial cells (BVs) BVs contain blood cells while loops of Henle do not

Simple Cuboidal Epithelium
Square in outline
Round nuclei
Lines surfaces involved in secretion and absorption
Lines collecting tubules – collecting tubules eventually merge with collecting ducts

Simple Columnar Epithelium
Rectangular in outline
Nuclei: round to oval, often on basal side of...
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