Ch 4 Epithelial Tissue, Glands, Cell connections Flashcards
Tissue & 4 types
Collections of specialized cells and the extracellular substances surrounding them
-Epithelial
-Connective
- Muscle
-Nervous
Extracellular Matrix
Non cellular substances surrounding the cells
Histology
Microscopic study of tissues
Biopsy
Process of removing tissues from patients surgically or with a needle for dianostic purposes
Autopsy
a postmordem examination of the organs to determine cause of death or to study the changes caused by disease
What are the 3 Embryonic germ layers
Endoderm, Mesoderm and ectoderm
Endoderm
A embryonic germ layer - inner layer that forms the lining of digestive tract
Mesoderm
A embryonic germ layer - middle layer that forms tissues such as muscle, bone and blood vessels
Ectoderm
A embryonic germ layer - outer layer that forms the skin
Neuroectoderm
A portion of the ectoderm – becomes the nervous system.
*Neural crest cells break away from neuroectoderm during development give rise to parts of peropheral nerves, skin pigment,etc
Epithelial Tissue
- Mostly composed of cells
- Covers body surfaces - Exterior, lining of digestive/respiratory tracts, the heart, blood vessles and body cavities
- Distinct Tissue surfaces - Most have apical surface
- Cell and Matrix connections - specialized cell contacts bind adjacet cells together
- Nonvascular
- Regeneration - Fast mitosis
What are the functions / purpose of epithelial tissue?
- Protection
- Barrier- Reduces water loss
- Filter - allowing some subtances through and not others
- Absorption & Secretion
Simple squamous Epithelium
Flat - squashed cells
Single layer
Diffusion/Filtration/some secretion/some protection
Lining of blood vessels and the heart, Alveoli of lungs
Simple Cuboidal Epithelium
Cube shaped
Single Layer
Secreation/Absorption & movement of particles
Kidney tubules
Simple columnar Epithelium
Column shaped, taller than wide
Single layer
Movement of particles, Secretion/Absorption
Lining of stomach and intestines
Stratified Squamous Epithelium
Flat, scaley
Multiple layers
Protection/barrier - water loss prevention
Epidermis/mouth
Pseudostratified Columnar Epithelium
Some appear columnar
Appear to have multple layers but all touch basement membrane
Synthesize and secrete mucous on to the free surface, move muscous
Trachea, lining of nasal cavity
Transitional Eptihelium
Appear cube or rounded cubed
Multple layers
Accomadte flucuations in the volume of fluid in organs
Urinary Bladder
What is the difference between Keratinized and non-keratinized?
Keratinized consists of living cells only in the deepest layers while dead layers are on top
Non-keratinized (moist) consists of living cells in both deep and superficial layers
Goblet cells
Responsible for synthizing and secreting mucous
What are the 6 types of cell connections
- Desmosomes
- Hemidesmosomes
- Tight junctions
- Adhesion belt
- Gap junction
- Intercalated discs
Desmosomes
Consists of adhesive glycoprotiens that bind cells together and extend to cytoplasm
Holds neighboring cells together
*Found in areas of stress - Skin
Hemidesmosomes
Similar to one half a desmosome
Attached epithelial cells to basement membrane
Tight Junction
Holds cells together and forms a permeability barrier so substances cannot seep through
Found near apical layer
Binds adjcent cells together to prevent passage of materials between cells
Adhesion belt
Found just below the tight junction
Located between plasma membrane of adjacent cells and acts as a weak glue
Gap Junction
A small specialized contact region between cells containing protien channels that aid in intracellular communication
Allows small water soluable molecules pass BETWEEN cells
Intercalated disc’s
Specialized Gap Junctions in the heart between cardiac muscles
*Contain both desmosomes and gap junction
Glands
Secretory organs
Composed primarily of epithelium with a supporting network of connective tissue
Exocrine Glands
Glands with ducts
*Maintains an open contact with epithelium tissue
Endocrine Glands
no ducts
Become seperated from epithelium
*Adrenal glands, Thyroid glands
Hormones
Cellular products of endocrine glands
Secreted into bloodstream and carried throughout the body
Multicellular glands
Composed of my cells
*Most exocrine cells
Classified by their structure of their ducts and secretory regions
Unicellular glands
Composed of a single cell
*Goblet cells
Simple glands
have a single, non branched duct
Compound glands
Multiple branched ducts
What are the 2 shapes of secretory regions in glands?
Tubular
Acinar/Alveolar
Also a combination of the 2 are : Tubuloacinar or Tubuloalveolar
What are the 3 types of secretion from a gland?
Merocrine secretion
Apocrine secretion
Holocrine secretion
Merocrine Secretion
Most common type
The release of secretoru products by exocytosis
Apocrine Secretion
release of secretory products as pinches off fragments of hte gland cells
Holocrine Secretion
Shedding of entire cell
What is the name of this Gland?
Simple tubular
What is the name of this Gland?
Simple coiled tubular
What is the name of this Gland?
Simple branched tubular
What is the name of this Gland?
Simple acinar
What is the name of this Gland?
Simple branched acinar
What is the name of this Gland?
Compound tubular
What is the name of this Gland?
Compound acinar
What is the name of this Gland?
Compound tubuloacinar
