Anatomy & Physiology Lecture Notes - Ch. 4 tissues - epithelium
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Transcript of Anatomy & Physiology Lecture Notes - Ch. 4 tissues - epithelium
Warm-Up
1. What is a tissue?2. The study of tissues is called ______.3. What are the 4 main types of
tissues? (See the intro to Chapter 4 in textbook)
Warm-UpWhat type of epithelial cell is shown below?
1. 2.
3.
4.
Simple Columnar Epithelium
Stratified Squamous Epithelium
Pseudostratified Columnar Epithelium
Simple Cuboidal Epithelium
Chapter 4
Tissue: group of cells that are similar in structure and function
Histology: study of tissues
Types of Tissues:1. Epithelium (covering)2. Connective (support)3. Muscle (movement)4. Nervous (control)
Preparing tissues for microscopy
Specimen is fixed (preserved) Cut into thin sections (slices) Stained with colored dyes
Part I: Epithelial Tissue
Epithelial Tissue
“epithe” = laid on, covering Structure:
1. Covering and lining epithelium2. Glandular epithelium
Function: Protection Absorption Filtration Secretion
Special Properties1. Polarity
Apical surface = exposed free surface or edge (some with microvilli, cilia)
Basal surface = lower, attached surface
2. Specialized contacts Fits close together to form continuous
sheets
Special Properties3. Supported by connective tissue
Rests on basement membrane 4. No blood supply (avascular)
Rely on diffusion and underlying connective tissue for food/O2
5. Regeneration – Replace lost cells
Classification Two names = (# cell layers) + (shape of cells) Cell Layers: simple or stratified Shapes: squamous, cuboidal, or columnar
Simple Epithelium
Absorption, secretion, filtration Very thin
Simple Epithelium
Simple Epithelium
Simple squamous Filtration, rapid diffusion Capillary walls, air sacs in lungs, kidney
filtration Serous membranes: slick layer lining
ventral body cavity and its organs
Simple Epithelium Simple cuboidal
Secretion & absorption Lines ducts of glands (salivary), kidney
tubules, ovary surface
Simple Epithelium
Simple columnar Absorption and
secretion Lines digestive tract Microvilli, cilia Mucous
membranes: lubricating mucus
Simple Epithelium
Pseudostratified columnar Rests on basement membrane – false
impression (pseudo) of being multi-layered
Secretes or absorbs Respiratory tract – cilia propels mucus
from lungs
Stratified Epithelium
2+ layers, more durable Main function = protect
Stratified Epithelium
Stratified squamous Withstand abuse, friction Esophagus, mouth, outer portion of skin
Stratified Epithelium
Stratified cuboidal Usually 2 layers Mainly in ducts of large glands (sweat,
mammary, salivary)
Sweat Gland Esophageal Gland
Stratified Epithelium
Stratified columnar Thick, waterproof layer Pharynx, male urethra, lining ducts
Transitional Epithelium
Able to change shape (cuboidal squamous)
Lining of hollow urinary organs (bladder, ureter, urethra)
Stretches when filled with urine
Glandular Epithelium
Gland: make and secrete a particular product
2 Types: Endocrine gland: produce hormones
secreted into tissue fluid or bloodstream
Exocrine gland: secrete products into ducts onto body surfaces or body cavities Eg. mucous, sweat, oil, saliva, bile
Exocrine Glands
Unicellular Multicellular Mucus cells or
goblet cells Duct structure