Tissues: Living Communities
Chapter 4
Introduction
• Cells of similar type and function cluster together to form
________________.
• Cells in our bodies are differentiated and have lost the ability to exist as an
isolated entity on their own.
• Cells exist in cooperative communities in multi-cellular organisms
Classification of Tissues
• Epithelial tissue
• Covers and lines
• Connective tissue
• Provides support
• Muscle tissue
• Enables movement
• Nervous tissue
• Controls work
Classification continued
• Most organs contain all 4 tissue types.
• The study of microscopic structures of tissues and organs is called
___________________ or microscopic anatomy.
• What is gross anatomy?
Epithelial Tissue
• Composed of sheets of cells that cover and line other types of tissue.
• Have an exposed surface that affords access to the surrounding
environment or to the inner openings of chambers and ducts.
• Acts as interface layer that separates and defines the beginning and
ending of different types of tissues.
Six Epithelial Tissue Functions
• _________________________________
• _________________________________
• _________________________________
• _________________________________
• _________________________________
• _________________________________
Characteristics of Epithelia
• Can be composed of single layer or multiple layers depending
on location.
• Epithelial cells share the following characteristics:
1. Polar - Each epithelial cell has an apical surface and a
basal surface
• _________________faces the lumen or body cavity
• __________________faces the underlying connective
tissue
2. Lateral surfaces are connected to neighboring cells by
_______________________________
3. Epithelial cells are ____________________- they have no
blood supply
4. Most epithelial cells are __________________- they DO
have nerve supply
Epithelial Tissue: Cellular Attachments
• Between the cell membranes of adjacent cells are channels that carry
nutrients to the cells and waste away
• Junctional Complexes – specialized attachments between epithelial cells
• 3 major types:
• ______________________
• Welded plaque
• Tough, resist tension and stretching (like Velcro)
• Found in: Skin, heart, uterus
• ______________________
• Cytoplasm continuous
• Exchange ions, nutrients – quickly transmit signals through
connexons
• Found in: Cardiac, smooth muscles
• _______________________
• Nothing can penetrate
• Prevent leakage
• Found in: Bladder, GI tract
Epithelial Cells: Basement Membrane
• Also called basal lamina - foundation of epithelial cells
• Meshwork of fibers that cements epithelial cell to underlying
connective tissue (CT)
• Varies in thickness
• Helps prevent cell from being torn off by intraluminal
pressures
• Acts as a partial barrier between epithelial cell and
underlying CT – substances have to travel through basement
membrane to get in and out of epithelial cells.
Surface Specializations
• Surfaces vary depending on location in body and
function
• May be smooth or contain _______________-fingerlike
projections
• If the cell contains microvilli, it is said to have a
_____________________.
• Brush border helps to increase surface area,
which aids in absorption. (can add up to 20
times of surface area).
• Hair-like projections, _________________- function
to move substances past the cell surface
• Skin cells may have ______________- protective,
waterproof substance
Classifications of Epithelia
• Characterized by 3 characteristics
1. Number of layers of cells
• Single layer is called ________________
• Found in protected parts of body because provide
minimal protection to underlying structures
• More than one layer is called ____________.
• Thicker and stronger and are on parts of body that
are subjected to mechanical or chemical stress.
2. Shape of cells
• Based on shape that is on exposed or on the luminal
surface
• ____________
• ____________
• ____________
3. Presence of surface specializations
• Keratin, cilia
Simple Squamous Epithelium
• Single layer of squamous shaped cells
• Found lining surfaces involved
in the passage of either gas
or liquid
Examples:_______________________________
• Mesothelium – includes lining of chest
_____________, lining of the abdomen
____________________,
and lining of the heart _______________
• Endothelium – includes lining of blood
vessels
SIMPLE SQUAMOUS
Simple Cuboidal Epithelium
• Single layer of cube-shaped
cells
• Round, dark-staining nuclei
aligned in a single row
• Occurs in areas of the body
where secretion and absorption
take place
• Examples:__________________________________________________
____________________________
SIMPLE CUBOIDAL
SIMPLE CUBOIDAL
Simple Columnar Epithelium
• Single layer of columnar shaped cells
• Nuclei aligned in a row at the
base of the cell near the
basement membrane
• Found in:
__________________________________________________
_____________________________
• _________________- apical surface is blanketed by
dense microvilli that maximize absorption by increasing
surface contact with nutrient-filled lumen.
• Another type of cell may be found between absorptive
cells. __________________- manufacture and store
mucus for lubrication
SIMPLE COLUMNAR
SIMPLE COLUMNAR
Stratified Squamous
Epithelium
• Multiple layers of squamous
shaped cells
• Occur in areas of the body
subject to mechanical
and chemical stresses
• Examples:
__________________________________
__________________________
• Continually being worn
away or sheared off
• Replaced by cells from a
deeper layer
STRATIFIED SQUAMOUS
STRATIFIED SQUAMOUS
Stratified Cuboidal Epithelium
• Multiple layers (usually two)
of cuboidal cells
• Found primarily along large
excretory ducts
• Examples:_____________
_____________________
_____________________
_________
STRATIFIED CUBOIDAL
Stratified Columnar Epithelium
• Found only in select parts of
the respiratory, digestive,
reproductive systems and
along some excretory ducts
• Rare
• Function in secretion and
protection
STRATIFIED COLUMNAR
Pseudostratified Columnar Epithelium
• “False” stratified – truly one layer of cells
• Cell nuclei are found at different levels
across the length of the tissue
• Some cells do not reach luminal
surface but all attach to basement membrane.
• Usually ciliated
• Found in:
________________________________________________________
____________
PSEUDOSTRATIFIED
COLUMNAR
PSEUDOSTRATIFIED
COLUMNAR
Transitional Epithelium
• Multiple layers of cells with varying shapes
• basal layer of _______________or _____________ cells
• superficial layer of ______________ or
___________________
cells
• Ability to stretch - found in areas
where changes in volume occur
• Examples:
________________________________________________
___________________________
• As epithelia stretches, layers often
thin depending on how much volume
is present
TRANSITIONAL EPITHELIUM
TRANSITIONAL EPITHELIUM
Glandular Epithelia
• _________________- a cell or group of cells that have ability to
manufacture and discharge a secretion.
• _________________- specialized protein molecules that are
produced in the Rough ER, packaged by the golgi and
discharged from the cell.
• Glands can be organized by factors:
• Endocrine vs. Exocrine
• Presence or absence of ducts
• Unicellular vs. Multicellular
• Number of cells that compose them
• Simple vs. compound
• Shape of secreting ducts
• Tubular, acinar, tubuloacinar
• Complexity of the structure
• Mucoid or serous
• Type of secretion made
• Merocrine, apocrine, or holocrine
• Manner in which secretions are stored and discharged
Endocrine Glands
• No ducts
• Blood stream delivers secretions to entire body
• Secretion is usually a hormone
• Regulate body functions (growth, maturity, sex cycle)
• Part of Endocrine System
ENDOCRINE GLANDS
Exocrine Glands
• Contain ducts (except for Goblet cells)
• Have local effect
• Examples:___________________________
___________________________________
_______________________
GOBLET CELL
ENDOCRINE vs. EXOCRINE
GLANDS
Unicellular Exocrine Gland:
Goblet Cell
• Ductless
• Opens into GI, respiratory
tracts, conjunctiva
• Composed of modified columnar
epithelial cell
• Secretes ______________: mixed
with water → mucus
Multicellular Exocrine Glands
• Contains:
• 1) ________________
• usually surrounded by connective tissue rich
in blood vessels and nerve fibers
• 2) ________________
• May be surrounded by myoepithelial cells
that assist with the discharge of secretions
into the glandular duct
Classification of Multicellular Exocrine Glands:
Shape
• Based on shape and number of tubes
Classification of Exocrine Glands: Manner of
secretion
• _____________________
• glands package their secretions and release them via exocytosis as they are manufactured
• Majority of glands
•
(ex: pancreas, sweat, salivary)
• ______________________
• glands store their secretions and then release the top part (apex) of the cell into the duct
system
•
(ex: mammary, some sweat)
• _____________________
• glands store their secretions and then release the entire contents of the cell
•
(ex: sebaceous)
Classification of Exocrine Glands:Type of
Secretions Produced
Type of secretion produced
• ________________________
• Watery
• Contain a high concentration of enzymes
• Pancreatic secretion
• _____________________
• Thick, viscous
• Mucus membranes (GI, resp)
• Composed of glycoproteins
• Mixed exocrine glands contain both
mucous and serous components
Connective Tissue
• Represents most abundant tissue by weight.
• Some systems are almost exclusively composed of connective tissue
• Skeletal, integumentary
• Appearance varies.
• Form and function may be different.
• Reserve for energy
• Protection
• Provides framework for structural support
• Is vascularized.
• Level of vascularity varies among connective tissue type.
Connective Tissue
Components
• All connective tissue is composed of distinct components
• 1. __________________________
• Collagenous
• Reticular
• Elastic
• 2. _____________________________
• 3. _____________________________
• Cells that stay in the tissues-____________
• Fibroblasts
• Adipocytes (fat cells)
• Reticular cells
• Cells that are able to migrate in and out of tissues_____________________________
• Mast cells
• Leukocytes (white blood cells)
• Macrophages (fixed and wandering)
Connective Tissue
Components
Connective Tissue
Components: Ground
Substance
• An homogenous material that ranges from
liquid to gel to solid.
• Composed of glycoproteins called
__________________________ (GAGs)
• Is a medium through which cells exchange
nutrients and waste with the
bloodstream.
• Acts as shock absorbing cushion and helps
to protect underlying delicate cells.
• Serves as obstacle for invading
microorganisms.