NSG 100  Included under the classification of

epithelial tissue are the exocrine and

Anatomy and Physiology in Nursing endocrine glands.

Learning Outcome: Epithelial Tissue Characteristics

 General makeup of a tissue. 1. Mostly composed of cells
 Epithelial tissue 2. Covers body surfaces
 Differentiate exocrine and endocrine 3. Distinct cell surfaces
glands, and unicellular and multicellular 4. Cell and matrix connections
glands and its category and function. 5. Nonvascular
 Connective tissues and its classification. 6. Capable of regeneration
 Types of muscle and nervous tissue and
their function.
 Mucous, serous and synovial
membranes and its structural and
functional characteristics.
 Inflammation and its process.
 Tissue repair.
 Age-related changes occur in cells and
in extracellular matrix.

Tissue
 A tissue is a group of cells with
similar structure and function, plus
the extracellular substance
surrounding them.
 It is the study of tissues called Functions of Epithelial Tissues
Histology 1. Protects underlying structures
2. Acts as a barrier
Types of Tissues 3. Permits passage of substances
Four (4) Tissue types in the human body: 4. Secretes substances
1. Epithelial – a covering or lining tissue 5. Absorption of substances
2. Connective – a diverse primary tissue
type that makes up part of every organ
in the body Classification of Epithelia
3. Muscle – a tissue that contracts or  Epithelial tissues are classified primarily
shortens, making movement possible according to the number of cell layers
4. Nervous – responsible for coordinating and the shape of the superficial cells.
and controlling many body activities  The cell layers can be simple, stratified,
or pseudostratified.
EPITHELIAL TISSUES  The cell shapes can be squamous,
 Epithelium, or epithelial tissue, covers cuboidal, columnar, or a special
and protects surfaces, both outside and transitional shape, that varies with the
inside the body. degree of stretch.
Layers:
a. Simple epithelium consists of a single layer of
cells, with each cell extending from the
basement membrane to the free surface.
b. Stratified epithelium consists of more than
one layer of cells, but only the basal layer
attaches the deepest layer to the basement
membrane.
c. Pseudostratified columnar epithelium is a
special type of simple epithelium, that appears
to be falsely stratified.
 It consists of one layer of cells, with all
the cells attached to the basement
membrane.
 Due to variations in the shape of the
cells, the epithelia appear stratified.

Simple Cuboidal Epithelium 2

Three (3) types of epithelium based on  A single layer of cube-like cells that
shapes of the epithelial cells: carry out active transport, facilitated
1. Squamous cells are flat or scalelike. diffusion, or secretion.
2. Cuboidal cells are cube-shaped—about  They have a greater secretory capacity
as wide as they are tall. than simple squamous epithelial cells.
3. Columnar cells tend to be taller than
they are wide.

Simple Squamous Epithelium 1

 A single layer of thin, flat cells.
 Some substances easily pass through
this thin layer of cells, but other
substances do not.
 examples
lungs--- allows for gas
exchange.
kidneys---helps filter wastes
from the blood while keeping
blood cells inside the blood
vessels.
Simple Columnar Epithelium 3
 A single layer of tall, thin cells. Stratified Squamous Epithelium 1
 The large size of these cells enables  forms a thick epithelium because it
them to perform complex functions, consists of several layers of cells.
such as secretion.  Though the deepest cells are cuboidal
 Ex. small intestine --- produces and or columnar and are capable of dividing
secretes mucus and digestive enzymes. and producing new cells, the naming is
based on the shape of the surface cells.
 Two types of stratified squamous
epithelia: keratinized stratified
squamous and nonkeratinized stratified
squamous epithelia.

Pseudostratified Columnar Epithelium 4

 secretes mucus, which covers its free
surface. Two types of stratified squamous epithelia
 Ex. Cilia in the airways move the mucus 1. Keratinized Stratified Squamous
and accumulated debris toward the Epithelium
throat, where it is swallowed.  Ex. outer layer of the skin
 The keratin reduces the loss of
water from the body.
2. Nonkeratinized Stratified Squamous
Epithelium
 Ex. mouth---is a moist
nonkeratinized stratified
squamous epithelium.
 provides protection against
abrasion and acts as a
mechanical barrier.
 Water, however, can move
across it more readily than
across the skin (keratinized
stratified squamous).
Stratified Cuboidal Epithelium 2
 consists of more than one layer of
cuboidal epithelial cells and relatively
rare
 Ex. sweat gland ducts, ovarian follicular
cells, and the salivary glands.
 It functions in absorption, secretion,
and protection.

Stratified Columnar Epithelium 3

 consists of more than one layer of
epithelial cells; the surface cells are
columnar but the deeper cells are
irregular or cuboidal in shape.
 relatively rare
 Ex. mammary gland ducts, the larynx,
Free Cell Surfaces
and a portion of the male urethra.
 Most epithelia have a free surface that
 This epithelium carries out secretion,
is not in contact with other cells and
protection, and some absorption.
faces away from underlying tissues.
 The characteristics of the free surface
Transitional Epithelium
reflect its functions.
 a special type of stratified epithelium
 The free surface can be smooth or lined
that can be greatly stretched.
with microvilli or cilia.
 The shape of the cells change as the
 Cilia move materials over the top of the
epithelium is stretched.
cell.
 Ex. lines cavities that can expand
 Microvilli increase surface area.
greatly, such as the urinary bladder.
 It also protects underlying structures,
Glands
like the urinary bladder, from the
 consists of one or more cells that make
caustic effects of urine.
and secrete a particular product called
secretion--contains protein molecules
in an aqueous (water based) fluid,
indicates active process in which
glandular cells obtain needed materials
from the blood (product) and discharge
via exocytosis
 secretory organs that secrete
substances onto a surface, into a cavity,
or into the bloodstream.
 composed primarily of epithelium, with
a supporting network of connective
tissue.

Two (2) major types that develop from

epithelial sheets:
1. Endocrine
  are ductless glands 1. highly vascularized except for
 Secretions(hormones) exits directly tendon, ligaments and cartilages
into the blood vessels that weave which are called avascular.
through the glands. 2. extracellular matrix---composed of
 Ex. thyroid, adrenal and pituitary different types of cell and other
2. Exocrine---glands with ducts nonliving substances outside the
 secretion exits through the ducts to cells.
the epithelial surface
 Ex. sweat and oil glands, liver, Functions of Connective Tissue
pancreas 1. Enclose and separate other tissues
 Most exocrine glands are 2. Connecting tissues to one another
multicellular, some are composed 3. Supporting and moving parts of the
of a single cell, like goblet cells, that body
secrete mucus. 4. Storing compounds
 Multicellular exocrine glands can be 5. Cushioning and insulating
classified according to the structure 6. Transporting
of their ducts and secretory regions: 7. Protecting
1. Simple glands--- single, non-branched
duct, some have branched ducts. Connective Tissue Cells 1
2. Compound --- have multiple,  The specialized cells of the various
branched ducts. connective tissues produce the
extracellular matrix.
Exocrine Gland Structures  The name of the cell identifies the cell
functions. ex. Prefix such as Blast, cytes
or clasts
 Blast-creates the matrix, Cytes-existing
cell, Clast-break down for remodelling
 Osteoblasts form bone, osteocytes
maintain it, and osteoclasts break it
down.
 Fibroblasts are cells that form fibrous
connective tissue, and fibrocytes
maintain it.
 Chondroblasts form cartilage and
chondrocytes maintain it.
 Found in connective tissue are cells
associated with the immune system,
Connective Tissue such as white blood cells.
 means “it connects body parts”  Macrophages are large cells that are
 Located throughout the body and most capable of moving about and ingesting
abundant in the body and widely foreign substances, including
distributed of the tissue types. microorganisms in the connective
 differs from the other three tissue types tissue.
and diverse in both structure and  Mast cells are nonmotile cells that
function. release chemicals, such as histamine,
 distinguishing characteristics: that promote inflammation.
 A. Cartilage
Extracellular Matrix a. Hyaline
 The extracellular matrix of connective b. Fibrocartilage
tissue has three major components: c. Elastic
protein fibers, ground substance, and B. Bone
fluid.
 Ground substance consists of non- 3. Fluid Connective Tissue
fibrous protein and other molecules.  Blood
 The structure of the matrix is
responsible for the functional
characteristics of connective tissues— 1. Types of Connective Tissues Proper
for example, they enable bones and A. Dense CT- large number of protein
cartilage to bear weight. fibers that form thick bundles and fill
nearly all of the extracellular space.
Matrix Protein Fibers Major categories:
Three (3) types of protein fibers—collagen,  Dense collagenous CT has an
reticular, and elastic—help form most extracellular matrix consisting
connective tissues. mostly of collagen fibers.
 Collagen fibers, which resemble o dense regular-same
microscopic ropes, are very flexible but direction (ex. tendons and
resist stretching. ligaments.) dense
 Reticular fibers are very fine, short irregular-multiple
collagen fibers that branch to form a directions (ex. dermis of
supporting network. the skin and in organ
 Elastic fibers have the ability to return capsules)
to their original shape after being  Dense Elastic CT -has abundant
stretched or compressed, giving tissue elastic fibers, which allows the
an elastic quality. tissue to stretch and recoil.
o Ex. vocal cords.
o A genetic condition
Classifications of Connective Tissue called Marfan
1. Connective Tissue Proper syndrome results from,
Types: in part the inability to
A. Dense CT (More fiber but less properly maintain and
ground substances) form elastic fibers.
a. Dense, regular elastic
b. Dense, regular collagenous Dense Regular Collagenous Connective Tissue
c. Dense, irregular elastic
d. Dense, irregular
collagenous
B. Loose CT (Fewer fiber but more
ground substances)
a. Areolar
b. Adipose
c. Reticular

2. Supporting Connective Tissue

Types:
  Cartilage is resilient because the
Dense Regular Elastic Connective Tissue proteoglycans of the matrix trap
water.
 Cartilage provides support, but if
bent or slightly compressed, it
resumes its original shape.

Three (3) types of cartilage:

 Hyaline cartilage is the most
abundant type of cartilage and has
many functions, such as covering
the ends of bones, where they form
joints.
 Fibrocartilage has more collagen
than does hyaline cartilage and is
able to withstand compression and
resist tearing or pulling. ex.
intervertebral disks, and in some
B. Loose connective tissue - consists of few joints, such as the knee and
proteins fibers that form a lacy network with temporomandibular (jaw) joints.
spaces filled with ground substances and  Elastic cartilage contains elastic
fluids. fibers in addition to collagen and
Three (3) subdivisions of loose connective proteoglycans which appear as
tissue: coiled fibers among bundles of
 Areolar connective tissue collagen fibers.
primarily consists of collagen  able to recoil to its original
fibers and a few elastic fibers. shape when bent ex.
 Adipose tissue consists of external ear, epiglottis, and
adipocytes, or fat cells, which auditory tube contain
contain large amounts of lipid elastic cartilage.
for energy storage. Adipose
tissue pads and protects parts B. Bone
of the body and acts as a  Bone is a hard connective tissue that
thermal insulator. consists of living cells and a mineralized
 Reticular tissue forms the matrix. Osteocytes are located within
framework of lymphatic tissue, lacunae.
such as in the spleen and lymph  The strength and rigidity of the
nodes, as well as in bone mineralized matrix enables bones to
marrow and the liver. support and protect other tissues and
organs.
 Two (2) types of bone tissue
2. Supporting Connective Tissue  Spongy bone has spaces
A. Cartilage between trabeculae or
 chondrocytes-major cell types plates, of bone and
 Collagen in the matrix give therefore resembles a
 cartilage flexibility and strength. sponge.
 Compact bone is more
solid, with almost no space
 between many thin layers  It is responsible for coordinating and
of mineralized matrix. controlling many body activities.
 Nervous tissue consists of neurons and
3. Fluid Connective Tissue support cells, termed glial cells.
A. Blood  The neuron is responsible for
 it is a liquid connective tissue conducting action potentials.
 It contains a liquid matrix, termed the  It is composed of three parts: a cell
plasma, along with formed elements. body, dendrites, and an axon.
 The formed elements are
erythrocytes, leukocytes, and Tissue Membranes
platelets.  A thin sheet or layer of tissue that
 It functions in transport of food, covers a structure or lines a cavity.
oxygen, waste, hormones, and  Most membranes consist of epithelium
other substances. and the connective tissue on which the
epithelium rests.
 There are four (4) tissue membranes in
the body: cutaneous, mucous, serous,
and synovial.
 Cutaneous membrane----a.k.a
MUSCLE TISSUE Skin is an external body surface
 The main function of muscle tissue is to membrane.
contract, or shorten, making movement  Mucous membranes--- line
possible. cavities that open to the
 Muscle contraction results from outside of the body such as the
contractile proteins located within the digestive, respiratory, and
muscle cells. reproductive tracts that
 Three (3) types: secretes mucus (but not all)
1. skeletal---muscle attaches to  functions: include
the skeleton and enables the protection, absorption,
body to move. and secretion.
2. cardiac---muscle of the heart; it  Serous membrane---line
is responsible for pumping cavities that do not open to the
blood. exterior of the body, such as
3. smooth---muscle forms the the pericardial, pleural, and
walls of hollow organs and can peritoneal cavities.
be seen in the skin and the  three components: a
eyes. layer of simple
 functions such as squamous epithelium,
moving food through its basement
the digestive tract and membrane, and a
emptying the urinary delicate layer of loose
bladder. connective tissue.
 do not contain glands,
but they secrete a small
NERVOUS TISSUE amount of fluid called
 forms the brain, spinal cord, and nerves serous fluid, which
lubricates the surface
of the membranes.
  Synovial membranes line the causes scar production and the loss of
cavities of freely movable some tissue function.
joints.  Tissue repair occurs in sequential steps.
 made up of modified
connective tissue cells.
 Synovial membranes
produce synovial fluid,
which makes the joint
very slippery, thereby
reducing friction and
allowing smooth
movement within the
joint.

Tissue Inflammation 1
 Inflammation is usually a beneficial
process occurring when tissues are
damaged.
 When viruses infect epithelial cells of
the upper respiratory tract,
inflammation and the symptoms of the
common cold are produced.
 The inflammatory process occurs in
stages.
 Inflammation mobilizes the body’s
defenses and isolates and destroys
microorganisms, foreign materials, and
damaged cells so that tissue repair can
proceed.
 Five (5) major symptoms: redness,
heat, swelling, pain, and disturbance of
function.

Tissue Repair 1
 Tissue repair involves substitution of
dead cells for viable cells that can occur
by regeneration or by fibrosis.
 Regeneration--- the new cells are the
same type as those that were
destroyed, and normal function is
usually restored.
 Fibrosis--- or replacement, a new type
of tissue develops that eventually