Histology Flashcards
(133 cards)
1
Q
Histology
A
the science and study of tissues
2
Q
tissue
A
a group of cells, usually with a common embryonic origin, that function together to carry out
specialized activities
3
Q
pathologist
A
a physician who examines cells and tissues to help other physicians make accurate
diagnoses
4
Q
4 types of tissues
A
epithelial
connective
muscular
nervous
5
Q
epithelial tissue
A
covers body surfaces; lines body cavities, hollow organs, and ducts (tubes);
and forms glands
6
Q
connective tissue
A
protects and supports the body and its organs, binds organs together, stores
energy reserves as fat, and provides immunity
7
Q
muscular tissue
A
generates the physical force needed to make body structures move
8
Q
nervous tissue
A
detects changes inside and outside the body and initiates and transmits nerve
impulses (action potentials) that coordinate body activities to help maintain homeostasis
9
Q
2 types of epithelial tissue
A
covering and lining epithelium
glandular epithelium
10
Q
covering and lining epithelium
A
outer covering of the skin and the outer covering of some
internal organs; lines body cavities, blood vessels, ducts, interiors of the respiratory, digestive,
urinary, and reproductive systems
11
Q
glandular epithelium
A
makes up secreting portions of glands such as sweat glands
12
Q
general features of epithelial tissue
A
Consists of closely packed cells with little extracellular material between them; arranged in
continuous sheets
Avascular
Epithelial tissue has a nerve supply
Has a high capacity for renewal by cell division (because it is subject to a certain amount of wear
and tear)
13
Q
avascular
A
lacks blood vessels; blood vessels that supply epithelial tissue are located in adjacent
connective tissues
14
Q
components of epithelial tissue
A
an apical (free) space surface
lateral surface
a basal surface
basement membrane
15
Q
an apical (free) surface
A
exposed to a body cavity, lining of an internal organ, or the exterior of the body (most superficial layer)
16
Q
lateral surface
A
face adjacent cells on either side
17
Q
basal surface
A
attached to a basement membrane (deepest layer)
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Q
basement membrane
A
a thin extracellular structure composed mostly of protein fibers; located
between the epithelial tissue and the underlying connective tissue layer; helps bind and support
the epithelial tissue
19
Q
classification of epithelial tissue
A
classified according to the arrangement of cells into layers and the
shape of the cells
arrangement of cells in layer
simple epithelium
pseudostratified epithelium
stratified epithelium
20
Q
secretion
A
the production and release of substances such as mucus, sweat or enzymes
21
Q
absorption
A
the intake of fluids or other substances such as digested food from
the intestinal tract
22
Q
pseudostratified epithelium
A
actually simple epithelium, but appears to have multiple
layers of cells because the cell nuclei lie at different levels and not all cells reach the
apical surface
23
Q
stratified epithelium
A
consists of two or more layers of cells that protect underlying tissues in locations where there is considerable wear and tear
24
Q
squamous cells
A
thin, allowing for the rapid passage of substances through them
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cuboidal cells
as tall as they are wide, shaped like cubes or hexagons; have microvilli at their apical surface and function in either secretion or absorption
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columnar cells
much taller than they are wide, like columns, protect underlying tissues.
Their apical surfaces may have cilia or microvilli; often specialized for secretion and
absorption
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transitional cells
change shape, from flat to cuboidal and back, as organs such as the urinary bladder stretch to a larger size, then collapse to a smaller size
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arrangement of simple epithelium
simple squamous epithelium
simple cuboidal epithelium
simple columnar epithelium ( noncilated and ciliated)
pseudostratified columnar epithelium ( noncilated and ciliated)
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stratified epithelium
stratified squamous epithelium ( keratinzed and nonkeratinzed)
stratified cuboidal epithelium
stratified columnar epithelium
transitional epithelium
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Simple squamous epithelium
a single layer of flat cells that resembles a tiled floor when
viewed from apical surface; centrally located nucleus that is flattened and oval or spherical in shape
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location of simple squamous epithelium
lines Lines heart, blood vessels, and lymphatic vessels (endothelium)
Lines air sacs of lungs, glomerular capsule of kidneys, and inner surface of the
tympanic membrane
Forms the epithelial layer of serous membranes such as peritoneum, pleura, or
pericardium (mesothelium)
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function of simple squamous epithelium
filtration, diffusion, osmosis, and secretion in serous membranes
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simple cuboidal epithelium
single layer of cube-shaped cells; round, centrally located nucleus
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location of simple cuboidal epithelium
Lines kidney tubules and smaller ducts of many glands
Makes up the secreting portion of some glands such as the thyroid gland
Covers surface of ovary
Lines anterior surface of capsule of the lens of the eye
Forms the pigmented epithelium at the posterior surface of the eye
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function of simple cuboidal epithelium
secretion and absorption
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noncilated simple columnar epithelium
a single layer of nonciliated column-like cells with
| nuclei near bases of cells; contains cells with microvilli and goblet cells
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microvilli
microscopic fingerlike projections that increase the surface area of the
plasma membrane to increase the rate of absorption
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goblet cells
modified columnar cells that secrete mucus, a slightly sticky fluid, at their apical surfaces
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location of noncilated simple columnar epithelium
lines most of the gastrointestinal tract (from stomach to anus), ducts of many glands, and gallbladder
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function of noncilated simple columnar epithelium
secretion and absorption
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Ciliated simple columnar epithelium
a single layer of ciliated column-like cells with nuclei
| near bases; contains goblet cells in some locations
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location of ciliated simple columnar epithelium
lines a few portions of upper respiratory tract, uterine (fallopian) tubes, uterus,
some paranasal sinuses, and central canal of spinal cord
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function of ciliated simple columnar epithelium
mucus secreted by goblet cells forms a film over respiratory surface that traps
inhaled foreign particles; cilia wave in unison and move mucus and any trapped foreign particles toward throat where it can be coughed up and swallowed or spit out.
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Pseudostratified columnar epithelium
not a true stratified tissue; nuclei of cells are at different
levels; all cells are attached to basement membrane, but not all reach the apical surface
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location of pseudostratified columnar epithelium
Lines the airways of most of upper respiratory tract and larger ducts of many
glands, epididymis, and part of male urethra
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function of pseudostratified columnar epithelium
ciliated variety secretes mucus that traps foreign particles, and cilia sweep
away mucus for elimination from body; nonciliated variety functions in absorption and
protection
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Stratified squamous epithelium
2+ layers of cells; cells in apical layer and several layers deep to it are squamous; as new cells grow at the basal layer, the deepest layers are pushed upward toward the surface
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Keratinized stratified squamous epithelium
develops a tough layer of keratin in apical layer and
| several layers deep to it
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Nonkeratinized stratified squamous epithelium
does not contain keratin in apical layer and several layers deep to it and remains moist
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location of Nonkeratinized stratified squamous epithelium
```
keratinized variety forms superficial layer of skin; nonkeratinized variety lines
wet surfaces (lining of mouth, esophagus, part of epiglottis, part of pharynx, and vagina),
covers tongue
```
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function of Nonkeratinized stratified squamous epithelium
protection; provides first line of defense against microbes
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stratified cuboidal epithelium
two or more layers of cells; cells in the apical layer are cubeshaped; fairly rare type
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location of stratified cuboidal epithelium
ducts of adult sweat glands and esophageal glands and part of male urethra
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function of stratified cuboidal epithelium
Protection and limited secretion and absorption
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stratified columnar epithelium
basal layers usually consist of shortened, irregularly shaped
cells; only apical layer has columnar cells; uncommon.
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location of stratified columnar epithelium
Lines part of urethra, large excretory ducts of some glands such as esophageal
glands, small areas in anal mucous membrane, and part of conjunctiva of eye
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function of stratified columnar epithelium
Protection and secretion
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transitional epithelium
variable in appearance; in relaxed or unstretched state, looks similar to
stratified cuboidal epithelium, except apical layer cells tend to be large and rounded; as tissue is
stretched, cells become flatter
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location of transitional epithelium
lines urinary bladder and portions of ureters and urethra
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function of transitional epithelium
allows urinary organs to stretch and maintain protective lining while holding
variable amounts of fluid without rupturing
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glandular epithelium
secretion accomplished by glandular cells that lie in clusters deep to the
covering and lining epithelium
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gland
may consist of one cell or a group of highly specialized epithelial cells that secrete
substances into ducts onto a surface or into the blood
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glands are classified as endocrine and exocrine
secretions (hormones) enter the interstitial fluid and then diffuse into the
bloodstream without flowing through a duct
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glands are classified exocrine
secrete their products into ducts that empty at the surface of covering and
lining epithelium such as the skin surface or the lumen (interior space) of a hollow organ
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connective tissue
one of the most abundant and widely distributed tissues in the body
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functions of connective tissue
Binds together, supports, and strengthens other body tissues
Protects and insulates internal organs
Compartmentalizes structures such as skeletal muscles
Is the major transport system within the body (blood)
Is the major site of stored energy reserves (adipose)
Is the main site of immune responses
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2 basic elements of connective tissue
cells
| extracellular matrix
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extracellular matrix
the material between its widely spaced cells; consists of protein
fibers and ground substance (the material between the cells and the fibers
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general features of connective tissue
Do not usually occur on body surfaces
Usually are highly vascular
Except for cartilage, connective tissue is supplied with nerves
Connective tissue cells
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Fibroblasts
large flat cells with branching processes; usually the most numerous; migrate through the connective tissue secreting the fibers and ground substance of the
extracellular matrix
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macrophages
develop from monocytes (a type of white blood cells); irregular shape with short branching projections; capable of engulfing bacteria and cellular debris by
phagocytosis
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plasma cells
small cells that develop from B lymphocytes (a type of white blood cells); secrete antibodies
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mast cells
abundant alongside the blood vessels that supply connective tissue; produce histamine (chemical that dilates small blood vessels as part of the inflammatory response); can kill bacteria
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adipocytes
fat cells; adipose cells; store triglycerides; found below the skin and around
organs such as the heart and kidneys
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connective tissue extracellular matrix
Each type of connective tissue has unique properties based on the specific extracellular
materials between the cells
Fluid, gel, or solid ground substance plus protein fibers
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ground substance
the component of connective tissue between the cells and fibers
supports and binds cells together
provides a medium through which substances are exchanged between the blood and cells
plays an active role in how tissues develop, migrate, proliferate, change shape, and carry out their metabolic functions
contains water and an assortment of large organic molecules
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fibers
Strengthen and support connective tissues
3 types in the extracellular matrix
collagen fibers
elastic fibers
reticular fibers
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collagen fibers
very strong and resist pulling forces; not stiff, promotes
tissue flexibility; often occur in parallel bundles that offer strength
Most types of connective tissue; bone, cartilage, tendons, and
ligaments
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elastic fibers
smaller in diameter than collagen fibers, branch and joint together to form a network within a tissue; strong but can be stretched up
to 1 ½ times their relaxed length without breaking
Plentiful in skin, blood vessel walls, and lung tissue
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reticular fibers
much thinner than collagen fibers; provide support and
strength; supporting framework of many soft organs
provide support in the walls of blood vessels and form branching
networks around fat cells, nerve fibers, and skeletal and smooth
muscle cells
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loose connective tissue
```
fibers are loosely arranged
areolar connective tissue
adipose tissue
reticular connective tissue
dense connective tissue
dense irregular connective tissue
elastic connective tissue
cartilage
liquid connective tissue
```
82
areolar connective tissue
one of the most widely distributed connective tissues; consists of
fibers arranged randomly and several kinds of cells embedded in a semifluid
ground substance
83
location of areolar connective tissue
in and around nearly every body structure (“packing material of the
body”); subcutaneous layer deep to skin, superficial region of dermis of skin,
connective tissue layer of mucous membranes, around blood vessels, nerves, and
body organs
84
function of areolar connective tissue
strength, elasticity, and support
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adipose tissue
cells called adipocytes; specialized for storage of triglycerides; new
blood vessels form with weight gain
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location of adipose tissue
Wherever areolar connective tissue is located; subcutaneous layer deep to skin, around heart and kidneys, yellow bone marrow, and padding around joints and behind eyeball in eye socket
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function of adipose tissue
reduces heat loss through skin; serves as an energy reserve; supports
and protects organs
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reticular connective tissue
fine interlacing network of reticular fibers and reticular cells
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location of reticular connective tissue
stroma (supporting framework) of liver, spleen, lymph nodes; red bone marrow; part of the basement membrane; around blood vessels and muscles
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function of reticular connective tissue
forms stroma of organs; binds together smooth muscle tissue cells;
filters and removes worn-out blood cells in spleen and microbes in lymph nodes
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dense regular connective tissue
contains more numerous, thicker, and denser fibers, but fewer cells than loose connective tissue
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description of dense regular connective tissue
extracellular matrix looks shiny white; consists mainly of collagen fibers regularly arranged in bundles
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location of dense regular connective tissue
forms tendons, most ligaments, and aponeuroses (sheet-like tendons
that attach muscle to muscle or muscle to bone)
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function dense regular connective tissue
provides strong attachment between various structures; tissue structure
resists pulling along long axis of fibers
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dense irregular connective tissue
consists predominantly of collagen fibers randomly arranged and a
few fibroblasts
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location of dense irregular connective tissue
often occurs in sheets (fascia), deeper region of dermis of skin, periosteum of bone, perichondrium of cartilage, joint capsules, various organs,
pericardium of the heart; also in heart valves
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function of dense irregular connective tissue
provides tensile strength in many directions
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elastic connective tissue
consists predominantly of elastic fibers; fibroblasts are present in spaces between fibers; unstained tissue is yellowish
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location of elastic connective tissue
lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal
cords, suspensory ligaments of penis, some ligaments between vertebrae
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function of elastic connective tissue
allows stretching of various organs; is strong and can recoil to original shape after being stretched
101
cartilage
Consists of a dense network of collagen fibers or elastic fibers firmly embedded in chondroitin sulfate (a rubbery component of the ground substance)
Can endure considerably more stress than loose and dense connective tissues
chondrocytes
perichondrium
no blood vessels or nerves except in the perichondrium
antiangiogenesis factor
heals poorly
102
chondrocytes
cells of mature cartilage
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perichondrium
a membrane of dense irregular connective tissue that surrounds the surface of most cartilage
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antiangiogenesis factor
secreted by cartilage to prevent blood vessel growth
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3 types of cartilage
Hyaline
Fibrocartilage
Elastic cartilage
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hyaline cartilage
contains a resilient gel as ground substance and appears in the body as a bluish-white, shiny substance; most abundant type of cartilage in the body
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location of hyaline cartilage
ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, and embryonic and fetal skeleton
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function of hyaline cartilage
provides smooth surfaces for movement at joints, as well as
| flexibility and support; weakest type of cartilage (can be fractured)
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fibrocartilage
consists of chondrocytes scattered among clearly visible thick bundles of collagen fibers within extracellular matrix; lacks perichondrium
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location of fibrocartilage
pubic symphysis, intervertebral discs, menisci of knee, and portions of tendons that insert into cartilage
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function of fibrocartilage
Support and joining structures together. Strength and rigidity
make it the strongest type of cartilage
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elastic cartilage
consists of chondrocytes located in a threadlike network of elastic fibers within the extracellular matrix; perichondrium present
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location of elastic cartilage
lid on top of larynx (epiglottis), part of external ear, and
| auditory (Eustachian) tubes
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function of elastic cartilage
provides strength and elasticity; maintains shape of certain structures
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bone tissue
each bone is an organ composed of different tissues: bone tissue, cartilage,
dense connective tissue, epithelium, blood-forming tissue, adipose tissue, and nerve tissue
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liquid connective tissue
( blood and lymph tissue)
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blood tissue
connective tissue with a liquid extracellular matrix (blood plasma) and red blood cells, white blood cells, platelets, and a variety of other substances
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lymph tissue
a fluid that flows in lymphatic vessels; a connective tissue that consists of several types of cells in a clear extracellular matrix similar to blood plasma
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membranes
flat sheets of pliable tissue that cover or line a part of the body
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epithelial membrane
combination of an epithelial layer and an underlying connective tissue layer
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principle epithelial membranes
mucous membranes, serous membranes, cutaneous membrane (skin), and synovial membranes (except these do not contain epithelium)
122
mucous membrane (mucosa)
lines a body cavity that opens directly to the exterior
Lines the entire digestive, respiratory, and reproductive systems and much of the urinary
system
Secretes mucus which prevents the cavities from drying out
Traps particles in the respiratory passageways, lubricates and absorbs food as it moves through the gastrointestinal tract, and secretes digestive enzymes
123
serous membrane
lines a body cavity that does not open directly to the exterior, and covers the
organs that lie within the cavity
Consists of 2 parts: parietal layer (attached to cavity wall) and visceral layer (covers and
attaches to the organs inside the cavities)
secretes serous fluid
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serous fluid
watery lubricating fluid that allows organs to glide easily over one another or to slide against the walls of cavities
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synovial membrane
lines the cavities of some joints
composed of areolar connective tissue and adipose tissue with collagen
do not have an epithelial layer
Contain cells which secrete synovial fluid
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synovial fluid
lubricates the ends of bones as they move at joints, nourishes the cartilage covering the bones, and removes microbes and debris from the joint cavity
127
musuclar tissue
Consists of elongated cells called muscle fibers that are highly specialized to generate force
Produces motion, maintains, posture, generates heat, and offers protection
classified into skeletal, cardiac, smooth
128
skeletal muscular tissue
usually attached to the bones of the skeleton
129
cardiac muscular tissue
the bulk of the wall of the heart
130
smooth muscular tissue
located in the walls of hollow internal structures (blood vessels, airways, digestive and urinary systems
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nervous tissue
consists of neurons and neuroglia
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neurons
nerve cells; sensitive to various stimuli which are converted into nerve
impulses and conducted to other neurons, muscle fibers, or to glands
133
neuroglia
do not generate or conduct nerve impulses, but serve protective and
supportive functions
