tissues Flashcards
groups of specialized cells and the extracellular
substances surrounding them.
tissues
the microscopic study of tissue structure
histology
four primary tissue types
(1) epithelial tissue, (2) connective tissue, (3) muscle tissue, and (4)
nervous tissue
found
virtually everywhere, both inside and outside the body.
Epithelium
especially important in hollow organs with openings
to the outside environment, because it protects against foreign materials
entering the body
epithelium
one surface of their cells is in direct contact with either the outside environment
or the contents of our hollow organs. The surface that is exposed is called the ________
surface.
free surface, or apical (A-pi-kal)
surface
The surface of the cells that is anchored in place is
called the
basal surface
attaches the epithelial cells to
underlying tissues.
basement membrane
Found throughout the body where it covers internal
and external surfaces. It also forms most of the glands.
EPITHELIAL TISSUE
EPITHELIAL TISSUE: FUNCTIONS
- Protecting underlying structures
- Acting as barriers
- Permitting the passage of substances
- Secreting substances
- Absorbing substance
consists of a single layer of cells, with each cell extending
from the basement membrane to the free surface
simple epithelium
consists of more than one layer of cells, but only the
deepest layer of cells attaches to the basement membrane.
Stratified epithelium
is a special type of simple epithelium.
The prefix pseudo- means false, so this type of epithelium appears to be
stratified but is not. It consists of one layer of cells, with all the cells attached to
the basement membrane. There appear to be two or more layers of cells because
some of the cells are tall and extend to the free surface, whereas others are
shorter and do not extend to the free surface
Pseudostratified columnar epithelium
cells are flat or scalelike.
Squamous
cells are cube-shaped—about as wide as they are tall.
cuboidal
cells tend to be taller than they
are wide
columnar
Diffusion, filtration, some
secretion, and some
protection against friction
Simple Squamous Epithelium
Single layer of flat, often
hexagonal cells; the nuclei
appear as bumps when
viewed in cross section
because the cells are so flat
Simple Squamous Epithelium
Secretion and absorption
by cells of the kidney
tubules; secretion by cells
of glands and choroid
plexuses; movement of
particles embedded in
mucus out of the terminal
bronchioles by ciliated cells
Simple Cuboidal Epithelium
Structure:
Single layer of cube-
shaped cells; some cells
have microvilli (kidney
tubules) or cilia (terminal
bronchioles of the lungs)
Simple Cuboidal Epithelium
Single layer of tall, narrow
cells; some cells have cilia
(bronchioles of lungs,
auditory tubes, uterine
tubes, and uterus) or
microvilli (intestines)
Simple Columnar Epithelium
Movement of particles out
of the bronchioles of the
lungs by ciliated cells;
partially responsible for
the movement of oocytes
through the uterine tubes
by ciliated cells; secretion
by cells of the glands, the
stomach, and the
intestines; absorption by
cells of the intestines
Simple Columnar Epithelium
Structure:
Single layer of cells; some
cells are tall and thin and
reach the free surface, and
others do not; the nuclei of
these cells are at different
levels and appear
stratified; the cells are
almost always ciliated and
are associated with goblet
cells that secrete mucus
onto the free surface
Pseudostratified Columnar Epithelium
Synthesize and secrete
mucus onto the free
surface and move mucus
(or fluid) that contains
foreign particles over the
surface of the free surface
and from passages
Pseudostratified Columnar Epithelium
Structure:
Several layers of
cells that are
cuboidal in the
basal layer and
progressively
flattened toward
the surface; the
epithelium can
be
nonkeratinized
(moist) or
keratinized; in
nonkeratinized
stratified
squamous
epithelium, the
surface cells
retain a nucleus
and cytoplasm;
in keratinized
stratified
epithelium, the
cytoplasm of cells
at the surface is
replaced by a
protein called
keratin, and the
cells are dead
Stratified Squamous Epithelium
the surface cells
retain a nucleus
and cytoplasm
nonkeratinized
stratified
squamous
epithelium
the
cytoplasm of cells
at the surface is
replaced by a
protein called
keratin, and the
cells are dead
keratinized
stratified
epithelium
Function:
Protects against
abrasion, forms a
barrier against
infection, and
reduces loss of
water from the
body
Stratified Squamous Epithelium
outer layer of the
skin;
Keratinized
mouth, throat,
larynx,
esophagus, anus,
vagina, inferior
urethra, and
corneas
nonkeratinized
Stratified cells
that appear
cuboidal when
the organ or tube
is not stretched
and squamous
when the organ
or tube is stretched by fluid
transitional epithelium
Function:
Accommodates
fluctuations in
the volume of
fluid in an organ
or a tube;
protects against
the caustic
effects of urine
transitional epithelium
a single layer of thin, flat cells. Some substances easily pass through this thin layer of cells, but other
substances do not.
Simple squamous epithelium
a single layer of cubelike cells that carry out active transport, facilitated diffusion, or secretion.
simple cuboidal epithelium
single layer of tall, thin cells. The large size of these cells enables them to perform complex
functions.
Simple columnar epithelium
actually a single layer of
cells, but the cells appear to be layered due to the differing heights of adjacent
cells and positions of their nuclei. This epithelium provides protection for the
body
Pseudostratified columnar epithelium
forms a thick epithelium because it
consists of several layers of cells. The deepest cells are cuboidal or
columnar and are capable of dividing and producing new cells. As these newly
formed cells are pushed to the surface, they become flat and thin
Stratified squamous epithelium
a special type of stratified epithelium that
can stretch
Transitional epithelium
best adapted for areas of
the body where filtration and diffusion are common
simple squamous epithelium
due to the larger
volume of these cells, has a greater secretory capacity
Simple cuboidal epithelium
Smooth free surfaces reduce friction. This kind of tissue is a specialized type of simple
squamous epithelium called
endothelium
Cell connection structures that mechanically bind epithelial cells together
are called
desmosomes
those that bind cells to the basement membrane are called
hemidesmosomes
the anchors of epithelial tissues to the underlying basement membrane,
preventing the movement of the tissue.
hemidesmosomes
cell connection structures that (1) form barriers and
(2) anchor cells to each other. form a barrier to movement of
molecules or ions between epithelial cells. In addition, anchor
cells together.
tight junction
are found just below the
tight junctions, and help the tight junctions anchor the epithelial cells to each
other
adhesion belt
consist of groups of channels that allow small molecules and ions to pass from one epithelial cell to an adjacent
one.
gap junction
specialized secretory organs, called
glands
are
composed of epithelium supported by a network of connective tissue.
glands
two major types of glands in the body
) endocrine glands, and (2)
exocrine glands
produce chemicals called hormones and are often
termed ductless glands based on their structure and mode of secretion.
Endocrine glands
produce a wide variety of products, such as saliva, sweat,
and digestive tract secretions. These secretions enter ducts, which are
continuous with the epithelial tissue surface
exocrine glands
•Usually characterized by large amounts of
extracellular materials that separate cells from
another.
connective tissue
CONNECTIVE TISSUE: FUNCTIONS
Enclosing and separating
Connecting tissues to one another
Supporting and moving
Storing
Cushioning and insulating
Transporting
Protecting
create
the matrix
blast
maintain it
cytes
break it down for remodeling
clast
are
large white blood cells that are capable of moving about and ingesting foreign
substances, including microorganisms in the connective tissue.
macrophages
nonmotile cells that release chemicals, such as histamine, that promote
inflammation.
mast cells
extracellular matrix of connective tissue has three major components
(1)
protein fibers, (2) ground substance, and (3) fluid
which resemble microscopic ropes, are very flexible but resist
stretching
collagen fibers
very fine, short collagen
fibers that branch to form a supporting network
reticular fibers
have the
ability to return to their original shape after being stretched or compressed,
giving tissue an elastic quality. This tissue stretches like a rubber band in
response to force and recoils when relaxed
elastic fibers
consists of relatively few protein fibers
that form a lacy network, with numerous spaces filled with ground substance
and fluid.
Loose connective tissue
Three subdivisions of loose connective tissue are
(1) areolar, (2)
adipose, and (3) reticular.
connective tissue primarily consists of collagen fibers and a few elastic
fibers.
AREOLAR TISSUE
Function:
Loose packing,
support, and
nourishment for
the structures
with which it is
associated
Areolar Connective Tissue
Structure:
Little
extracellular
matrix
surrounding cells;
the adipocytes, or
fat cells, are so
full of lipid that
the cytoplasm is
pushed to the
periphery of the
cell
Areolar Connective Tissu
Function:
Packing material,
thermal insulator,
energy storage,
and protection of
organs against
injury from being
bumped or jarred
adipose tissue
Function:
Provides a
superstructure for
lymphatic and
hemopoietic
tissues
Reticular Tissue
Structure:
Fine network of
reticular fibers
irregularly
arranged
reticular tissue
consists of adipocytes, or fat cells, which
contain large amounts of lipids for energy storage. Unlike other connective
tissue types, this tissue is composed of large cells
adipose tissue
has a relatively large number of protein fibers
that form thick bundles and fill nearly all of the extracellular space.
dense connective tissue
has an extracellular matrix
consisting mostly of collagen fibers (table 4.7a). Structures made up of _______include tendons, which attach muscle to bone;
many ligaments, which attach bones to other bones; and much of the dermis,
which is the connective tissue of the skin.
Dense collagenous connective tissue
the collagen fibers are oriented in the
same direction, and so the tissue is called
dense regular
in organ capsules, the fibers are oriented in many different directions,
and so the tissue is called
dense irregular
has abundant elastic fibers among its
collagen fibers. The elastic fibers allow the tissue to stretch and recoil.
Dense elastic connective tissue
Structure:
Matrix
composed of
collagen fibers
running in
somewhat the
same direction
in tendons and
ligaments;
collagen fibers
run in several
directions in
the dermis of
the skin and in
organ capsules
Dense Regular Collagenous Connective Tissue
Function:
Withstand
great pulling
forces exerted
in the direction
of fiber
orientation due
to great tensile
strength and
stretch
resistance
Dense Regular Collagenous Connective Tissue
Structure:
Matrix
composed of
collagen fibers
and elastin
fibers running
in somewhat
the same
direction in
elastic
ligaments;
elastic fibers
run in
connective
tissue of blood
vessel walls
Dense Regular Elastic Connective Tissue
Function:
Capable of
stretching and
recoiling like a
rubber band
with strength
in the direction
of fiber
orientation
Dense Regular Elastic Connective Tissue
composed of chondrocytes (KON-droh-sites), or
cartilage cells, located in spaces called lacunae (la-KOO-nee; small spaces)
within an extensive matri
cartilage
Structure:
Collagen fibers are
small and evenly
dispersed in the
matrix, making the
matrix appear
transparent; the
chondrocytes are
found in spaces, or
lacunae, within the
firm but flexible
matrix
Hyaline Cartilage
Function:
Allows growth of
long bones;
provides rigidity
with some flexibility
in the trachea,
bronchi, ribs, and
nose; forms strong,
smooth, yet
somewhat flexible
articulating
surfaces; forms the
embryonic skeleton
Hyaline Cartilage
Structure:
Collagen fibers
similar to those in
hyaline cartilage;
the fibers are more
numerous than in
other cartilages and
are arranged in
thick bundles
fibrocartilage
Function:
Somewhat flexible
and capable of
withstanding
considerable
pressure; connects
structures subjected
to great pressure
fibrocartilage
Structure:
Similar to hyaline
cartilage, but matrix
also contains elastic
fibers
Elastic Cartilage
Function:
Provides rigidity
with even more
flexibility than
hyaline cartilage
because elastic
fibers return to their
original shape after
being stretched
elastic cartilage
the most
abundant type of cartilage and has many functions. It covers the ends of bones
where they come together to form joints
hyaline
has more collagen than does hyaline cartilage, and
bundles of collagen fibers can be seen in the matrix. can
withstand both compression and pulling or tearing forces.
Fibrocartilage
contains elastic fibers in addition to collagen and
proteoglycans. The elastic fibers appear as coiled fibers among bundles of
collagen fibers. _____ is able to recoil to its original shape when bent.
Elastic cartilage
a hard connective tissue that consists of living cells and a
mineralized matrix
bones
Structure:
Hard, bony
matrix
predominates;
many
osteocytes (not
seen in this
bone
preparation)
are located
within
lacunae; the
matrix is
organized into
layers called
lamellae
bone
Function:
Provides great
strength and support and
protects
internal
organs, such as
the brain; bone
also provides
attachment
sites for
muscles and
ligaments; the
joints of bones
allow movements
bones
has spaces between trabeculae (trah-BEK-you-lee), or plates, of
bone and therefore resembles a sponge
spongy bone
more solid, with almost no space between many thin layers of mineralized matrix
compact bone
unique because the matrix is liquid, enabling blood cells and
platelets, collectively called formed elements, to move through blood
vessels
blood
Structure:
Formed
elements and a
fluid matrix
blood
Function:
Transports
oxygen, carbon
dioxide,
hormones,
nutrients, waste
products, and
other
substances;
blood
main function is to to contract, or shorten, making
movement possible
muscle tissue
what we normally think of as “muscle” (table
4.11a). It is the meat of animals and constitutes about 40% of a person’s body
weight.
skeletal muscle
Structure:
cells
or fibers
appear
striated
(banded);
cells are large,
long, and
cylindrical,
with many
nuclei
skeletal muscle
Function:
Movement of
the body;
under
voluntary
control
skeletal muscle
Structure:
cells
are cylindrical
and striated
and have a
single
nucleus; they
are branched
and
connected to
one another
by
intercalated
disks, which
contain gap
junctions
cardiac muscle
Function:
Pumps the
blood; under
involuntary
(unconscious)
control
cardiac muscle
Structure:
cells
are tapered at
each end, are
not striated,
and have a
single nucleus
smooth muscle
Function:
Regulates the
size of organs,
forces fluid
through
tubes,
controls the
amount of
light entering
the eye, and
produces
“goose
bumps” in the
skin; under
involuntary
(unconscious)
control
smooth muscle
forms the brain, spinal cord, and nerves. It is responsible for
coordinating and controlling many body activities
nervous tissue
or nerve cell, is responsible for conducting electrical
signals. It is composed of three parts: (1) a cell body, (2) dendrites, and (3) an
axon
neuron
contains the nucleus and is the site of
general cell function
cell body
usually
receive stimuli that lead to electrical changes
dendrites
conduct
electrical signals, which usually originate at the base of an axon where it joins
the cell body and travel to the end of the axon.
axons
are the support cells of the nervous system. They nourish, protect, and
insulate the neurons.
glial cell
Structure:
A neuron consists
of dendrites, a cell
body, and a long
axon; glia, or
support cells,
surround the
neurons
nervous tissue
Function:
Neurons transmit
information in the
form of action
potentials, store
information, and
integrate and
evaluate data; glia
support, protect,
and form
specialized sheaths
around axons
nervous tissue
thin sheet or layer of tissue that covers a structure
or lines a cavity. Most membranes consist of epithelium and the connective
tissue on which the epithelium rests.
tissue membrane
Line cavities that open to the outside
and often contain mucous glands which secretes mucus.
Mucous Membranes
line the trunk cavities and cover the organs located within these cavities.
serous membrane
line the joint cavities
Synovial Membranes
• flamma, flame
• The body’s response to tissue damage caused by:
1. Infection
2. Trauma
• It mobilizes the body’s defenses to isolate and destroy
harmful agents, allowing tissue repair.
• Five key symptoms: redness, heat, swelling, pain, and
disturbance of function.
• Although inflammation can be painful, it is typically
beneficial for recovery.
inflammation
Chemical mediators like ______ and______ are
released during inflammation.
histamine and prostaglandins
occurs when fluids and proteins, like fibrin, move into
tissues, helping to prevent infection spread.
edema
a type of white blood cell, fight infections but die
after ingesting bacteria, forming pus.
neutrophils
•The substitution of viable cells for dead cells.
• Occurs in two major ways: 1)regeneration or 2) fibrosis
tissue repair
•Cells divides more slowly as people age. Injuries heal
more slowly.
•Extracellular matrix containing collagen and elastic
fibers become less flexible and less elastic.
Consequently, skin wrinkles elasticity in arteries is
reduced, and bones break more easily.
tissue aging
