Tissues Flashcards
What is Histology?
Study of tissues
What are Tissues?
specialized cells that have a common function
What is an Extracellular Matrix?
fluids, protein fibers, and macromolecules that surround the tissue
What types of tissues are there?
Epithelial
Connective
Muscle
Nervous
What are their general functions?
Epithelial - covers and lines surfaces
Connective - provides support
Muscle - Movement
Nervous - Controls work
Characteristics of Epithelial
Little to no extracellular matrix
apical/basal/lateral surfaces
avascular
basement membrane
Lume
Functions of Epithelial
Protection
Selectively Permeable
Secretion
Absorption
Filtration
Sensation
Define Cell Junctions
Types of connections between the lateral surface of epithelial cells
Types of Cell Junctions
Tight Junctions
Desmosomes
Gap Junctions
Define Tight Junctions
adhering proteins that bind near the apical side of the cell, encircling the cell
Tight Junction is AKA
Zonula Occludens
Functions of Tight Junctions
creates a seal to prevent substances from passing between the cells
Tight Junctions are found in
GI tract
small/large intestine
Define Desmosomes
protein plaques w/ intermediate and protein filaments that are like a button between adjacent cells
Desmosomes is AKA
Macula Adherens
Functions of Desmosomes
prevents mech. stress
gets stuck together in order to prevent them to fall apart from each other
Desmosomes are found in
Skin
Heart
UterusDe
Define Hemidesmosomes
half of a desmosome
anchors the cell at the basal side to the basement membrane
Define Gap Junctions
uses connexon as a protein; transmembrane proteins in a circle to form a pore between cells
Gap Junctions AKA
Nexus
Functions of Gap Junctions
allows passage of molecules between cells to coordinate cellular activities or communication
Gap Junctions are found in
respiratory tract w. cilia
cardiac muscle
What are glands?
individual cells or organst
What are glands made of?
mostly epithelial tissue
What types of glands are there?
Exocrine
Endocrine
Define Endocrine Glands
ductless glands that secrete hormones
Define Exocrine Glands
contain ducts for secretions to fo to the surface locally
Where are Exocrine Glands found?
Sweat, enzymes, saliva
Characteristic of Unicellular
may not have ducts
What are the Exocrine glands # of cells?
Unicellular
Multicellular
Characteristic of multicellular
contains acini
- sacs that secrete products into ducts
Merocrine Glands are found in
Saliva, tears, sweat, etc
What are the 3 secretion methods of Exocrine Glands?
Merocrine Glands
Apocrine Glands
Holocrine Glands
Define Merocrine Glands
secretions packaged in vesicles within cells and then released to the environment
Define Apocrine Glands
AG accumulate secretions at apical part of therir cytoplasm pinch off and release secretions
Define Holocrine Glands
cells that accumulate secretions and then disintegrate more viscous (thickly)
Apocrine Glands are found in
skin, axillary, inguinal, anal , armpit, groin, mammary glands and areolar regions
what is the Epi tissues classified by?
the amount/number of layers and shape of the cell
Holocrine Glands are found in
sebacous glands in skin
What are the layers of the epithelial tissue
Simple Epithelium
Stratified Epithelium
Define Simple Epithelium
single layer of
