Exam 1: Ch.1 Epithelium and Epithelial Glands Flashcards
What are the four basic types of tissues?
- Epithelial
- Connective
- Nervous
- Muscle
What are the three general functions of epithelium?
- Absorption
- Secretion
- Provide a barrier
What are the three specialized functions of epithelium?
- Transport molecules across epithelium
- Selective Permeability = Prevent transport of materials across epi.
- Sensory (ex: taste buds, retina in eye)
What are the 5 basic characteristics of epithelium?
- Cells are adjacent to each other
- Ass. with a complete or partial basement membrane
- Avascular, obtain nutrients by diffusion
- Ass. with vascular CT
- Cells are held together by cell junctions
What are the two parts of a complete basement membrane and what cells are they produced by?
- basal lamina – produced by epithelium cells
2. reticular lamina – produced by fibroblasts in the CT
What does a partial basement membrane include?
basal lamina ONLY
What are the 4 functions of the basement membrane?
- provides a surface for epithelial cell attachment
- molecular filter–very limited
- limits stretch
- directs migration of cells (i.e. during wound healing)
What are the two functions of the CT that epithelium is associated with?
- provides nutrition
2. source of defensive cells (macrophages, neutrophils, etc.)
What are the four types of Cell Junctions?
- Zonula Occludens = tight junctions
- Zonula Adherens = adhesion belt
- Macula Adherens = desmosome
- Gap junctions
What are the junctions that involve the sharing of intrinsic membrane proteins between adjacent cells?
Zonula Occludens = tight junctions
What are the two functions of Zonula Occludens (tight junctions)?
- provides strong attachment
2. prevents the passage of materials between cells
Zonula Adherens (adhesion belt) are regions consisting of what two things?
- cadherins (linkage proteins) b/w cells
2. marginal bands (microfilaments) that attach cytoskeleton to the cell membrane at these areas
What are the two functions of Zonula Adherens (adhesion belts)?
- strong attachment
2. provide cell structural stability
What is the function of Macula aherens (desmosomes)?
provides strong attachment
Gap junctions are ___ connexins (proteins) arranged in an cylinder. The size of the openings can be controlled by the cell. A _____ = 1 complete structure.
six; connexon
What are the two functions of gap junctions?
- strong attachment
2. transport materials b/w cells
List in order from the free cell surface and deep, the Junctional Complex.
- Zonula Occludens
- Zonula Adherens
- Macula Adherens
What help to connect epithelial cells to the basal lamina?
Hemidesmosomes, (essentially, half a desmosome)
What are Focal Point Contacts?
integrin (a transmembrane protein of the cell membrane) binds to structural CT glycoproteins and also connects to cytoskeleton
What two junctions hold the epithelium to the basement membrane and CT below?
- hemidesmosomes
2. Focal Point Contacts
What autoimmune skin disease causes large blistering lesion that burst, but do heal? The cause is due to antibodies binding to parts of hemidesmosomes
Bullous Pemphigoid
What autoimmune skin disease causes skin blistering that does not heal easily and usually has excessive bleeding, and can be fatal? Cause is antibodies binding to parts of desmosomes.
Pemphigus Vulgaris
What is an acute bacterial infection of the SI that is caused by toxins disrupting proteins in the zonula occludens?
Cholera; allows losee of water and electrolytes form CT below epithelium
What are the 4 types of Simple Epithelium?
- Simple Squamous
- Simple Cuboidal
- Simple Columnar
- Ciliated Pseudostratified Columnar Epithelium (Respiratory Epithelium)
~single cell thick