Chapter 4 - Tissues Flashcards
Collections of specialized cells and the extracellular substances surrounding them
Tissues
Body tissues are classified into:
4 types
structure of the cells
composition of the noncellular substances surrounding the cells (called
the extracellular matrix)
functions of the cells
The four primary tissue types:
epithelial tissue
connective tissue
muscle tissue
nervous tissue
the microscopic study of tissues
Histology
the process of removing
tissue samples from patients surgically or with a needle for diagnostic purposes.
biopsy
an examination of the organs of a
dead body to determine the cause of death or to study the changes caused by a disease.
autopsy
-blast means?
bud or germ
Approximately 13 or 14 days after fertilization, the embryonic stem cells that give rise to a new individual form a slightly elongated disk
consisting of two layers:
epiblast
hypoblast
Cells of the epiblast then migrate
between the two layers to form the three embryonic germ layers:
ectoderm
mesoderm
endoderm
give rise to all the tissues of the body
The germ layers
the inner layer, forms the lining
of the digestive tract and its derivatives.
endoderm
the middle layer, forms tissues such as muscle, bone, and blood vessels
mesoderm
the outer layer, forms the skin.
ectoderm
the portion of the ectoderm called __ becomes the nervous system
neuroectoderm
the groups of cells that break away from the neuroectoderm during development that give rise to parts of the peripheral nerves, skin pigment, the medulla of the adrenal gland, and many tissues of the face.
neural crest cells
covers and protects surfaces, both outside and inside the body
Epithelial tissue, or epithelium
characteristics common to most types of epithelial tissue:
- Mostly composed of cells.
- Covers body surfaces.
- Distinct cell surfaces.
- Cell and matrix connections.
- Nonvascular.
- Capable of regeneration.
where cells are exposed and not
attached to other cells.
free, or apical surface
where cells are attached to other epithelial cells.
lateral surface
attached to a basement membrane.
basal surface
often lines the lumen of ducts, vessels, and cavities.
free surface
a specialized type of extracellular material secreted by epithelial and connective tissue cells.
basement membrane
Functions of Epithelial Tissues:
- Protecting underlying structures.
- Acting as a barrier.
- Permitting the passage of substances.
- Secreting substances.
- Absorbing substances.
Classification of Epithelial Tissues based on the number of cell layers in each:
- Simple epithelium
- Stratified epithelium
- Pseudostratified columnar epithelium
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 basal layer attaches the deepest layer to the
basement membrane.
Stratified epithelium
pseudo- means?
false
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.
Pseudostratified columnar epithelium
three types of epithelium based on idealized shapes of the epithelial cells:
- Squamous
- Cuboidal
- Columnar
cells are flat or scalelike
Squamous
cells are cube-shaped—about as wide as
they are tall.
Cuboidal
(tall and thin, similar to a column) cells tend to be taller than they are wide
Columnar
consists of one layer of flat, or
scalelike, cells that rest on a basement membrane
Simple squamous epithelium
consists of several layers of cells.
Near the basement membrane, the cells are more cube-shaped, but at the free surface the cells are flat or scalelike
Stratified squamous epithelium
are columnar in shape (taller than they
are wide) and, although they appear to consist of more than one layer, all the cells rest on the basement membrane
Pseudostratified columnar epithelial cells
Roughly cuboidal to columnar
when not stretched and squamouslike when stretched
Transitional epithelium
S: Single layer of flat,
often hexagonal cells
F: Diffusion, filtration,
some secretion, and some
protection against friction
L: Lining of blood vessels
and the heart, lymphatic vessels etc. (kidney)
Simple Squamous Epithelium
S: Single layer of cube shaped cells.
F: Secretion and
absorption by cells of the kidney
tubules etc.
L: Kidney tubules, glands
and their ducts etc. (kidney)
Simple Cuboidal Epithelium
S: Single layer of tall,
narrow cells
F: 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 small
and large intestines
L: Glands and some ducts,
bronchioles of the lungs, auditory
tubes, uterus, uterine tubes,
stomach, intestines, gallbladder,
bile ducts, ventricles of the brain (Lining of
stomach and intestines)
Simple Columnar Epithelium
S: Multiple layers of cells that
are cube-shaped in the basal layer and
progressively flattened toward the surface
F: Protection against abrasion, a barrier against
infection, reduction of water loss from the body
L:
Keratinized— skin
nonkeratinized—mouth,
throat, larynx, esophagus, anus,
vagina, inferior urethra, cornea
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
S: Multiple layers of
somewhat cube-shaped cells
F: Secretion, absorption,
protection against infection
L: Sweat gland ducts,
ovarian follicular cells, salivary
gland ducts
Stratified Cuboidal Epithelium
S: Multiple layers of cells
with tall, thin cells resting on layers
of more cube-shaped cells
F: Protection, secretion
L: Mammary gland ducts,
larynx, a portion of the male urethra
Stratified Columnar Epithelium
S: Single layer of cells;
some cells are tall and thin and
reach the free surface, and others
do not
F: Synthesize and secrete
mucus onto the free surface;
move mucus (or fluid) that
contains foreign particles over the
surface of the free surface and
from passages
L: Lining of the nasal
cavity, nasal sinuses, auditory
tubes, pharynx, trachea, bronchi
of the lungs
Pseudostratified Columnar Epithelium
S: Stratified cells that
appear cube-shaped when the
organ or tube is not stretched and
squamous when the organ or tube
is stretched by fluid
F: Accommodate
fluctuations in the volume of fluid
in organs or tubes; protect against
the caustic effects of urine
L: : Lining of the urinary
bladder, ureters, superior urethra
Transitional Epithelium
specialized columnar epithelial cells that are responsible for synthesizing and secreting mucus
goblet cells
are extensions of the cell that greatly increase free surface area. They occur in cells that absorb or secrete, such as serous membranes and the lining of the small intestine
Microvilli
are a specialized, elongated form of microvilli found in sensory structures, such as the inner ear
Stereocilia
consist of adhesive
glycoproteins that bind cells together and intracellular proteins
attached to intermediate filaments that extend into the cytoplasm
of the cells
desmosomes
similar to one-half of a desmosome, attach epithelial cells to the basement
membrane.
Hemidesmosomes
hold cells together and form a permeability
barrier
Tight junctions
formed by proteins in the
plasma membranes of adjacent cells that join one another to make
a very tight seal
Tight junctions
in glycoproteins, found just below the
tight junction
adhesion belt
a small, specialized contact region
between cells containing protein channels that aid intercellular communication by allowing ions and small molecules to pass from one cell to another
gap junction
contain both gap junctions and desmosomes that help hold adjacent cells in close contact.
intercalated disks
composed primarily of epithelium, with a supporting network of connective tissue
Glands
Glands with ducts are
called
exocrine glands (Both the glands and their
ducts are lined with epithelium)
some glands become
separated from the epithelium of their origin and have no ducts; these are called
endocrine glands (have extensive blood vessels)
cellular products of endocrine
glands
hormones
glands that are composed of many cells
multicellular glands
glands that are composed of a single cell
unicellular glands
glands that have a single, nonbranched duct
Simple glands
if there are multiple secretory regions that branch off the duct, then the gland is called
branched
have multiple, branched ducts
Compound glands
Glands with secretory regions
shaped as tubules
tubular
shaped in saclike structures
acinar or alveolar
most common type of secretion
merocrine secretion
involves the release of secretory products by exocytosis
merocrine secretion
involves the release of secretory products as pinched off fragments of the gland cells
Apocrine secretion
involves the shedding of entire cells
Holocrine secretion
a diverse primary tissue type that makes up
part of every organ in the body.
Connective tissue
differs from the other three tissue types in that it consists of cells separated from each other by abundant extracellular matrix.
Connective tissue
Functions of Connective Tissue (7)
- Enclosing and separating other tissues.
- Connecting tissues to one another.
- Supporting and moving parts of the body.
- Storing compounds.
- Cushioning and insulating.
- Transporting.
- Protecting.
extracellular matrix is produced by?
specialized cells of the various connective tissues
blasts
create the matrix
cytes
maintain
clasts
break it down for remodeling
cells that form fibrous connective tissue
Fibroblasts
maintain fibrous connective tissue
fibrocytes
form cartilage
Chondroblasts
maintain cartilage
chondrocytes
also called adipose cells, contain large amounts of lipid.
Adipocytes
play important roles in inflammation
Mast cells
continuously move from blood vessels into connective tissues.
White blood cells, or leukocytes
are large, phagocytic cells found in some connective tissue types. They are derived from monocytes, a type of
white blood cell.
Macrophages
fragments of hemopoietic cells containing enzymes and special proteins that function in the clotting process to reduce bleeding from a wound.
Platelets
a type of adult stem cell that persist in connective tissue. They have the potential to form multiple cell types, such as fibroblasts or smooth muscle
cells, in response to injury
Undifferentiated mesenchymal cells
The extracellular matrix of connective tissue has three major components:
(1) protein fibers, (2) ground substance, and (3) fluid
Three types of protein fibers
collagen
reticular
elastic
consist the protein of collagen.
collagen fibers
e most abundant protein in the body
collagen
synthesized within fibroblasts and secreted into
the extracellular space
collagen
there are how many types of collagen fibers?
20
very fine collagen fibers, not a chemically distinct category of fibers, and very
short, thin fibers that branch to form a network.
Reticular fibers
consist of the protein elastin
Elastic fibers
has the ability to return to its original
shape after being stretched or compressed, giving tissue an elastic quality.
Elastic fibers
secrete elastin polypeptide chains, which are
linked together to form a network.
Fibroblasts
provide the elasticity of skin, lungs, and
arteries.
Elastic fibers
consists of nonfibrous molecules
ground substance
“shapeless” background against which the collagen fibers are seen through the microscope
ground substance
The two major components of ground substance:
hyaluronic acid
proteoglycans.
a long, unbranched polysaccharide chain composed of repeating disaccharide units. I
hyaluronic acid
a large molecule that consists of a protein core attached to many long polysaccharides called glycosaminoglycans
proteoglycan monomer
a large molecule that consists of a protein core attached to many long polysaccharides called glycosaminoglycans
proteoglycan monomer
Embryonic Connective Tissue (2)
Mesenchyme
Mucous connective tissue
Adult Connective Tissue (2)
Loose connective tissue
Dense connective tissue
Loose connective tissue (3)
Areolar
Adipose
Reticular
Dense connective tissue (4)
Dense, regular collagenous
Dense, regular elastic
Dense, irregular collagenous
Dense, irregular elastic
Supporting Connective Tissue (2)
Cartilage (Hyaline, Fibrocartilage, Elastic)
Bone (Spongy, Compact)
Fluid Connective Tissue (2)
Blood (Red blood cells, White blood cells, Platelets)
Hemopoietic tissue (Red marrow, yellow marrow)
Two major categories of connective tissue
embryonic
adult
composed of fibroblasts surrounded by semifluid extracellular matrix containing delicate reticular fibers
mesenchyme
The major source of remaining embryonic connective tissue in the newborn is in the umbilical cord, where it is called
mucous connective tissue
consists of relatively few
protein fibers that form a lacy network, with numerous spaces filled with ground substance and fluid.
Loose Connective Tissue
the “loose packing” material of
most organs and other tissues; it attaches the skin to underlying tissues
Areolar tissue
appears white at birth, but it turns yellow with age because of the accumulation of pigments
Yellow
adipose
a plant pigment that humans can metabolize as a source of vitamin A.
carotene
found in specific areas of the body, such
as the axillae (armpits), the neck, and near the kidneys.
brown adipose tissue
forms the framework of lymphatic tissue
Reticular tissue
has a relatively large number of protein
fibers, which form thick bundles and fill nearly all of the extracellular space.
Dense Connective Tissue
has protein fibers in the
extracellular matrix that are oriented predominantly in one direction
Dense regular
has abundant collagen fibers, which give this tissue a white appearance.
Dense regular collagenous
consists of
parallel bundles of collagen fibers and abundant elastic fibers
Dense regular elastic
lies along the posterior of the neck, helping hold
the head upright.
nuchal ligament
contains protein fibers
arranged as a meshwork of randomly oriented fibers.
Dense irregular connective tissue
forms most of the dermis as well as the connective tissue capsules that surround organs such as the kidney and spleen
Dense irregular collagenous
is found in the walls of elastic arteries. In addition to collagen fibers, oriented in many directions, the layers of this tissue contain abundant elastic fiber
Dense irregular elastic
composed of cartilage cells within an
extensive and relatively rigid matrix
Cartilage
The surface of nearly all
cartilage is surrounded by a layer of dense irregular connective tissue called
perichondrium
spaces which chondorocytes are located
lacunae
has large amounts of both collagen fibers and proteoglycans
Hyaline cartilage
found where strong support and some flexibility are needed, such as in the rib cage
and within the trachea and bronchi
Hyaline cartilage
has more collagen fibers than proteoglycans
Fibrocartilage
slightly compressible
and very tough. It is found in areas of the body where a great deal of pressure is applied to joints, such as in the knee, in the jaw, and between the vertebrae.
Fibrocartilage
has numerous elastic fibers in addition to
collagen and proteoglycans dispersed throughout its matrix. It is found in areas that have rigid but elastic
properties, such as the external ears
Elastic cartilage
a hard connective tissue that consists of living cells and
mineralized matrix
bone
has organic and inorganic portions.
Bone matrix
The organic portion consists of?
protein fibers, primarily collagen,
and other organic molecules
The mineral, or inorganic, portion
consists of specialized crystals called
hydroxyapatite (which contains calcium and phosphate)
Intervertebral disks
Fibrocartilage
Growing long bones
Hyaline Cartilage
External ears
Elastic Cartilage
bone cells
Osteocytes
has spaces between trabeculae or plates, of bone and therefore resembles a sponge
Spongy bone
more solid, with almost no space between
many thin layers, or lamellae
Compact bone
(T/F) bone can repair itself much more readily than can cartilage
True (Bone, unlike cartilage, has a rich blood supply)
unusual among the connective tissues because the matrix between the cells is liquid
blood
move freely within a fluid matrix
blood cells (Blood’s liquid matrix allows it to flow rapidly through the body)
Acts as scaffolding to provide
strength and support without the greater
weight of compact bone
Spongy Bone
forms a solid outer shell on bones that keeps
them from being easily broken or punctured
Compact Bone
ends of long bones
spongy bone
shafts of long bones
compact bone
forms blood cells
Hemopoietic tissue
In adults, hemopoietic tissue is found in
bone marrow
the soft connective tissue in the cavities
of bones
bone marrow
hemopoietic tissue surrounded by a framework of reticular fibers
red marrow
produces red and white blood cells and
platelets
Hemopoietic tissue
marrow of most bones
red marrow
consists of yellow adipose tissue and does not produce blood cells.
Yellow marrow
children
red marrow
adult
Yellow marrow
contracts, or shortens, with a force and therefore is responsible for movement
muscle tissue
meat of animals and constitutes about 40%
of a person’s body weight
Skeletal muscle
under voluntary (conscious) control
Skeletal
muscle
are striated or banded, because of the arrangement of contractile proteins within the cells
Skeletal
muscle
under involuntary (unconscious) control
Cardiac muscle
muscle of the heart
Cardiac muscle
forms the walls of hollow organs
Smooth muscle
responsible for a number of functions, such as moving
food through the digestive tract and emptying the urinary bladder
Smooth muscle
controlled involuntarily.
Smooth muscle
found in the brain, spinal cord, and nerves and
is characterized by the ability to conduct electrical signals
called action potentials.
Nervous tissue
consists of neurons,
which are responsible for its conductive ability, and support cells called glia
Nervous tissue
nerve cells
neurons (conducting cells of nervous
tissue)
three major parts of neuron
cell body
dendrites
axon
contains the nucleus
and is the site of general cell functions.
cell body
consist of projections of cytoplasm surrounded by membrane.
dendrites and axons
usually receive action potentials
dendrites (much shorter than axons and have multiple branches at their ends)
usually conducts action potentials away from
the cell body
axon
have multiple dendrites and a single axon
Multipolar
neurons
have a single dendrite and an axon.
Bipolar neurons
have only a single, short process that extends
from the cell body and then divides into two branches, which extend to the periphery and to the central nervous system
Pseudo unipolar neurons
are the support cells of the brain spinal
cord, and peripheral nerves
glia
nourish, protect, and
insulate neurons
glia
a thin sheet of tissue that covers a structure
or lines a cavity.
tissue membrane
(T/F) There are four tissue membranes in the body, one external and three internal.
True
external membrane
skin (cutaneous
membrane)
The three major categories of internal
membranes:
mucous
serous
synovial membranes
lines cavities and canals that
open to the outside of the body, such as the digestive, respiratory, excretory, and reproductive passages
Mucous Membranes
Mucous membranes consist of epithelial cells, their basement membrane, and a
thick layer of loose connective tissue called
lamina propria
a viscous protein substance
mucus
lines cavities that do not open to the
exterior of the body such as the pericardial, pleural, and
peritoneal cavities.
Serous Membranes
three components of serous membrane:
mesothelium (a layer of simple squamous epithelium)
basement membrane
delicate layer of loose connective tissue.
Serous membranes do not contain glands, but they
secrete a small amount of fluid called
serous fluid
lubricates the serous membranes, making their surfaces slippery.
serous fluid
line freely movable joints
Synovial Membranes
produce synovial fluid
Synovial Membranes
rich in hyaluronic acid, making the joint fluid very slippery, thus facilitating smooth
movement within the joint.
synovial fluid
the response that occurs when
tissues are damaged.
inflammation
mobilizes the body’s
defenses, isolates and destroys microorganisms and other injurious agents, and removes foreign materials and damaged cells, so
that tissue repair can proceed
inflammatory response
Inflammation has five major manifestations:
redness
heat
swelling
pain
disturbed function
released or activated in the tissues and the
adjacent blood vessels after a person is injured
chemical mediators
increases the pressure in the tissue, which can also stimulate neurons and cause pain
edema
substitution of viable cells for dead cells by
regeneration or replacement.
Tissue repair
the new cells are the same type as those that were destroyed, and normal function is usually restored.
regeneration
a new type of tissue develops which eventually produces a scar and causes
the loss of some tissue function.
replacement
Cells are classified into three groups according to their
ability to regenerate:
labile
stable
permanent
continue to divide throughout life.\
labile
include
adult stem cells and other cells of the skin, mucous membranes, and hemopoietic and lymphatic tissues. Damage to these cells can be repaired completely by regeneration
labile cells
such as those of connective tissues and glands, including the liver, pancreas, and endocrine glands, do not normally divide after growth ceases, but they retain the ability to divide and are capable of regeneration in response to injury.
stable
have a very limited ability to replicate and, if killed, are usually replaced by a different type of cell. S
permanent cells
If the edges of the wound are close
together, as in a surgical incision, the wound heals by a process called
primary union
If the edges are not close together, or if tissue loss has been extensive, the process is called
secondary union
binds the edges of the wound together
fibrin
seals the wound
and helps prevent infection
scab
a delicate, granular-appearing connective tissue that consists of fibroblasts,
collagen, and capillaries, replaces the clot.
Granulation tissue
consists of dense irregular collagenous connective tissue
scar
