L3: Tissues Pt. 1 Flashcards
The four basic types of tissues in the human body contribute to homeostasis by providing diverse functions including protection, support, communication among cells, and resistance to disease, to name just a few.
Tissues
A cell is a complex collection of compartments, each of which carries out a host of biochemical reactions that make life possible.
Cell
Cells usually work together as part of ___.
Tissues
The structure and properties of a specific tissue are influenced by factors such as the nature of the ___ that surrounds the cells and the connections between the cells that compose the tissue.
extracellular material
Tissues may be hard, semisolid, or even liquid in their consistency, a range exemplified by ___, fat, and ___.
bone; blood
is a group of cells that usually have a common origin in an embryo and function together to carry out specialized activities.
Tissue
is the science that deals with the study of tissues.
Histology
The greek word histo- means
tissue
The greek word -logy means
study of
is a physician who examines cells and tissues to help other physicians make accurate diagnoses.
Pathologist
The greek word patho- means
disease
Body tissues can be classified into four basic types according to their structure and function namely:
Epithelial tissue, Connective tissue, Muscular tissue, and Nervous tissue
Type of tissue that covers body surfaces and lines hollow organs, body cavities, and ducts; it also forms glands.
Epithelial tissue
Type of tissue that allows the body to interact with both its internal and external environments.
Epithelial tissue
Type of tissue that protects and supports the body and its organs.
Connective tissue
Various types of this type of tissue that bind organs together, store energy reserves as fat, and help provide the body with immunity to disease-causing organisms.
Connective tissue
Type of tissue that is composed of cells specialized for contraction and generation of force.
Muscular tissue
Type of tissue that generates heat that warms the body.
Muscular tissue
Type of tissue that detects changes in a variety of conditions inside and outside the body and responds by generating electrical signals called nerve action potentials (nerve impulses) that activate muscular contractions and glandular secretions.
Nervous tissue
Other term for nerve action potentials?
Nerve impulses
Epithelial tissue and most types of connective tissue, except ___, ___, and ___, are more general in nature and have a wide distribution in the body.
cartilage; bone; blood
Normally, most cells within a tissue remain anchored to other cells or structures. Only a few cells, such as ___, move freely through the body, searching for invaders to destroy.
phagocytes
is the removal of a sample of living tissue for microscopic examination.
Biopsy
The greek word bio- means
life
The greek word -opsy means
to view
This procedure is used to help diagnose many disorders, especially cancer, and to discover the cause of unexplained infections and inflammations.
Biopsy
TRUE or FALSE. Each of the four types of tissues has different cells that vary in shape, structure, function, and distribution.
t
are contact points between the plasma membranes of tissue cells.
Cell junctions
What are the five most important types of cell junctions?
Tight junctions, Adhering junctions, Desmosomes, Hemidesmosomes, and Gap junctions
consist of weblike strands of transmembrane proteins that fuse together the outer surfaces of adjacent plasma membranes to seal off passageways between adjacent cells
Tight Junctions
Cells of epithelial tissue that lines the stomach, intestines, and urinary bladder have many ___ junctions
Tight Junctions
They inhibit the passage of substances between cells and prevent the contents of these organs from leaking into the blood or surrounding tissues.
Tight Junctions
contain plaque, a dense layer of proteins on the inside of the plasma membrane that attaches both to membrane proteins and to microfilaments of the cytoskeleton
Adhering Junctions
Transmembrane glycoproteins called ___ in adhering junctions join the cells.
Cadherins
Each cadherin inserts into the plaque from the opposite side of the plasma membrane, partially crosses the intercellular space (the space between the cells), and connects to cadherins of an adjacent cell.
Adhering Junctions
In epithelial cells, adhering junctions often form extensive zones called ___ because they encircle the cell similar to the way a belt encircles your waist.
adhesion belts
TRUE or FALSE. Tight junctions help epithelial surfaces resist separation during various contractile activities, as when food moves through the intestines.
FALSE (Adhering Junctions)
TRUE or FALSE. Most epithelial cells and some muscle and nerve cells contain cell junctions.
t
The greek word desmo- means
band
Also contain plaque and have transmembrane glycoproteins (cadherins) that extend into the intercellular space between adjacent cell membranes and attach cells to one another
Desmosomes
TRUE or FALSE. The plaque of desmosomes does not attach to microfilaments. Instead, a desmosome plaque attaches to elements of the cytoskeleton known as intermediate filaments, which consist of the protein keratin.
t
The intermediate filaments extend from desmosomes on one side of the cell across the intracellular fluid (cytosol) to desmosomes on the opposite side of the cell. This structural arrangement contributes to the stability of the cells and tissue.
Desmosomes
In desmosomes, these spot weld–like junctions are common among the cells that make up the ___ (the outermost layer of the skin) and among ___ in the heart.
epidermis; cardiac muscle cells
prevent epidermal cells from separating under tension and cardiac muscle cells from pulling apart during contraction.
Desmosomes
The greek word hemi- means
half
resemble desmosomes, but they do not link adjacent cells. The name arises from the fact that they look like half of a desmosome
Hemidesmosomes
However, the transmembrane glycoproteins in hemidesmosomes are ___ rather than cadherins.
integrins
On the inside of the plasma membrane, integrins attach to intermediate filaments made of the protein keratin. On the outside of the plasma membrane, the integrins attach to the protein laminin, which is present in the basement membrane. Thus, ___ anchor cells not to each other but to the basement membrane.
Hemidesmosomes
At gap junctions, membrane proteins called ___ form tiny fluid-filled tunnels called connexons that connect neighboring cells
connexins
The plasma membranes of ___ junctions are not fused together as in tight junctions but are separated by a very narrow intercellular gap (space).
Gap Junctions
Through the ___, ions and small molecules can diffuse from the cytosol of one cell to another, but the passage of large molecules such as vital intracellular proteins is prevented.
connexons
The transfer of nutrients, and perhaps wastes, takes place through gap junctions in ___ such as the lens and cornea of the eye.
avascular tissues
This allows the cells in a tissue to communicate with one another. In a developing embryo, some of the chemical and electrical signals that regulate growth and cell differentiation travel via ___
Gap Junctions
also enable nerve or muscle impulses to spread rapidly among cells, a process that is crucial for the normal operation of some parts of the nervous system and for the contraction of muscle in the heart, gastrointestinal tract, and uterus.
Gap Junctions
The first obvious difference between the epithelial tissue and connective tissue is the ___ in relation to the extracellular matrix
number of cells
In an ___ many cells are tightly packed together with little or no extracellular matrix, whereas in a ___ a large amount of extracellular material separates cells that are usually widely scattered.
epithelial tissue; connective tissue
The second obvious difference is that an ___ has no blood vessels, whereas most ___ have significant networks of blood vessels.
epithelial tissue; connective tissue
In fact, ___ contains and distributes almost all the blood vessels in the body
Connective tissue
Another key difference is that epithelial tissue almost always forms ___ and is not covered by another tissue. An exception is the epithelial lining of blood vessels where blood constantly passes over the epithelium.
surface layers
TRUE or FALSE. Because epithelial tissue lacks blood vessels and forms surfaces, it is always found immediately adjacent to blood vessel–rich connective tissue, which enables it to make the exchanges with blood necessary for the delivery of oxygen and nutrients and the removal of wastes that are critical processes for its survival and function.
t
The ___ is a major difference between epithelial tissue and connective tissue.
ratio of cells to extracellular matrix
consists of cells arranged in continuous sheets, in either single or multiple layers. Because the cells are closely packed and are held tightly together by many cell junctions, there is little intercellular space between adjacent plasma membranes.
Epithelial tissue or epithelium
plural word of epithelium
Epithelia
Epithelial tissue may be classified into two general types:
Surface epithelium; Glandular epithelium
(covering and lining epithelium) forms the outer covering of the skin and some internal organs and the inner lining of structures such as blood vessels, ducts, body cavities, and the lining of the respiratory, digestive, urinary, and genital systems. In other words, it covers or lines a surface.
Surface epithelium
makes up the secreting portion of glands, such as the thyroid gland, suprarenal (adrenal) glands, sweat glands, and digestive glands.
Glandular epithelium
Functionally, ___ protects, secretes (mucus, hormones, and enzymes), absorbs (nutrients in the digestive canal), and excretes (various substances in the urinary tract).
epithelial tissue
The various surfaces of surface epithelium often differ in structure and have specialized functions and namely are
Apical surface, lateral surfaces, basal surface
faces the body surface, a body cavity, the lumen (interior space) of an internal organ, or a tubular duct that receives cell secretions. It may also contain cilia or microvilli
Apical (free) surface
face the adjacent cells on either side, may contain tight junctions, adhering junctions, desmosomes, and/or gap junctions.
lateral surfaces
is opposite the apical surface, the deepest layer of epithelial cells adhere to extracellular materials such as the basement membrane. Hemidesmosomes in the ___ of the deepest layer of epithelial cells anchor the epithelium to the basement membrane
basal surface
In discussing epithelia with multiple, layers, the term ___ refers to the most superficial layer of cells, and the ___ is the deepest layer of cells.
apical layer; basal layer
The ___ is found between an epithelial tissue and a connective tissue.
basement membrane
Under certain conditions, basement membranes become markedly thickened, due to increased production of ___ and ___
collagen; laminin
TRUE or FALSE. In untreated cases of diabetes mellitus, the basement membrane of small blood vessels (capillaries) thickens, especially in the eyes and kidneys. Because of this the blood vessels cannot function properly, and blindness and kidney failure may result.
t
is a thin extracellular layer that commonly consists of two layers, the basal lamina and reticular lamina.
basement membrane
The word lamina means
thin layer
is closer to—and secreted by—the epithelial cells. It contains proteins such as laminin and collagen, as well as glycoproteins and proteoglycans
basal lamina
the ___ molecules in the basal lamina adhere to integrins in hemidesmosomes and thus attach epithelial cells to the basement membrane
laminin
is closer to the underlying connective tissue and contains proteins such as collagen produced by connective tissue cells called fibroblasts
Reticular lamina
In addition to attaching to and anchoring the epithelium to its underlying connective tissue, they also form a surface along which epithelial cells migrate during growth or wound healing, restrict passage of larger molecules between epithelium and connective tissue, and participate in filtration of blood in the kidneys.
Basement membrane
Epithelial tissue has its own nerve supply but, is ___, relying on the blood vessels of the adjacent connective tissue to bring nutrients and remove wastes.
avascular
The prefix a- means
without
The word -vascular means
vessels
Exchange of substances between an epithelial tissue and connective tissue occurs by
diffusion
___ has many different roles in the body; the most important are protection, filtration, secretion, absorption, and excretion. In addition, it combines with nervous tissue to form special organs for smell, hearing, vision, and touch
Epithelial tissue
Types of surface epithelium are further classified according to two characteristics:
the arrangement of cells into layers and the shapes of the cells
Characteristic of the types of surface epithelium where the cells are arranged in one or more layers depending on function
Arrangement of cells in layers
There are 3 types of surface epithelium based on the characteristic of arrangement of cells in layers which are
Simple epithelium, Pseudostratified epithelium, Stratified epithelium
is a single layer of cells that functions in diffusion, osmosis, filtration, secretion, or absorption.
Simple epithelium
is the production and release of substances such as mucus, sweat, or enzymes.
Secretion
is the intake of fluids or other substances such as digested food from the intestinal tract.
Absorption
Functions associated with Simple epithelium
Secretion and absorption
The prefix pseudo- means
False
appears to have multiple layers of cells because the cell nuclei lie at different levels and not all cells reach the apical surface; it is actually a simple epithelium because all its cells rest on the basement membrane. Cells that do extend to the apical surface may contain cilia; others (goblet cells) secrete mucus.
Pseudostratified epithelium
The word stratum means
layer
consists of two or more layers of cells that protect underlying tissues in locations where there is considerable wear and tear.
Stratified epithelium
Characteristic of the types of surface epithelium that vary in shape depending of their function
Cell shapes
There are 4 types of surface epithelium based on the characteristic of cell shapes which are:
Squamous cells, Cuboidal cells, Columnar cells, and Transitional cells
The word SKWĀ-mus means
flat
are thin, which allows for the rapid passage of substances through them.
Squamous cells
are as tall as they are wide and are shaped like cubes or hexagons. They may have microvilli at their apical surface and function in either secretion or absorption.
Cuboidal cells
are much taller than they are wide, like columns, and protect underlying tissues. Their apical surfaces may have cilia or microvilli, and they often are specialized for secretion and absorption.
Columnar cells
change shape, from squamous to cuboidal and back, as organs of the urinary system such as the urinary bladder stretch (distend) to a larger size and then collapse to a smaller size.
Transitional cells
When we combine the two characteristics (arrangements of layers and cell shapes), we come up with the following types of epithelial tissues:
Simple epithelium and Stratified epithelium
Under the Simple epithelium, there are 4 subtypes which are
Simple squamous epithelium, Simple cuboidal epithelium, Simple columnar epithelium, and Pseudostratified columnar epithelium
Under the Simple squamous epithelium are another 2 subtypes namely
Endothelium and Mesothelium
Type of simple squamous epithelium that lines heart, blood vessels, lymphatic vessels
Endothelium
Type of simple squamous epithelium that forms epithelial layer of serous membranes
Mesothelium
Under the Simple columnar epithelium are another 2 subtypes namely
Nonciliated and Ciliated
Type of simple columnar epithelium that lacks cilia
Nonciliated
Type of simple columnar epithelium that contains cilia
Ciliated
Under the Stratified epithelium, there are 4 subtypes namely
Stratified squamous epithelium, Stratified cuboidal epithelium, Stratified columnar epithelium, and Urothelium or transitional epithelium
Under the Stratified squamous epithelium are 2 subtypes namely ___ and ___ that is based on the shape of the cells at the apical surface
Nonkeratinized and Keratinized
Type of stratified squamous epithelium that lacks keratin
Nonkeratinized
Type of stratified squamous epithelium that contains keratin
Keratinized
Type of Stratified epithelium that lines most of urinary tract
Urothelium or transitional epithelium
___ and___ are the bases for classifying surface epithelium.
Cell shapes and Arrangement of layers
forms the outer covering of the skin and some internal organs. It also forms the inner lining of blood vessels, ducts, and body cavities, and the interior of the respiratory, digestive, urinary, and reproductive systems.
Surface Epithelium
is 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.
Simple Squamous Epithelium
Most commonly (1) lines the cardiovascular and lymphatic system (heart, blood vessels, lymphatic vessels), where it is known as endothelium and (2) forms the epithelial layer of serous membranes of the abdominal and thoracic cavities (peritoneum, pleura, pericardium), where it is called mesothelium
Simple Squamous Epithelium
The word endo- means
within
The word -thelium means
covering
The word meso- means
middle
Also found in air sacs of lungs, glomerular capsule of kidneys, inner surface of cornea, inner surface of tympanic membrane (eardrum).
Simple Squamous Epithelium
Present at sites of filtration (such as blood filtration in kidneys) or diffusion (such as diffusion of oxygen into blood vessels of lungs) and at site of secretion in serous membranes. Not found in body areas subject to mechanical stress (wear and tear)
Simple Squamous Epithelium
is a single layer of cube-shaped cells; round, centrally located nucleus. The shape is obvious when tissue is sectioned and viewed from the side and couldn’t form small tubes as they are more pie-shaped but stull nearly as high as they are wide at the base.
Simple Cuboidal Epithelium
Location of the Simple Cuboidal Epithelium
Covers surface of ovary; lines anterior surface of capsule of lens of the eye; forms pigmented epithelium at posterior surface of retina of the eye; lines kidney tubules and smaller ducts of many glands; makes up secreting portion of some glands such as thyroid gland and ducts of some glands such as pancreas.
Its function secretion and absorption
Simple Cuboidal Epithelium
is a single layer of nonciliated columnlike cells with oval nuclei near base of cells; contains (1) columnar epithelial cells with microvilli at apical surface and (2) goblet cells.
Nonciliated Simple Columnar Epithelium
fingerlike cytoplasmic projections, increase surface area of plasma membrane, thus increasing cell’s rate of absorption.
Microvilli
are modified columnar epithelial cells that secrete mucus, a slightly sticky fluid, at their apical surfaces. Before release, mucus accumulates in upper portion of cell, causing it to bulge and making the whole cell resemble a goblet or wine glass.
Goblet cells
Location of the Nonciliated Simple Columnar Epithelium
Lines digestive canal (from stomach to anus), ducts of many glands, and gallbladder.
The functions of this type of epithelium are the following: Secretion and absorption; larger columnar cells contain more organelles and thus are capable of higher level of secretion and absorption than are cuboidal cells. Secreted mucus lubricates linings of digestive, respiratory, and genital tracts, and most of urinary tract; helps prevent destruction of stomach lining by acidic gastric juice secreted by stomach.
Nonciliated Simple Columnar Epithelium
is a single layer of ciliated columnlike cells with oval nuclei near base of cells. Goblet cells are usually interspersed.
Ciliated Simple Columnar Epithelium
Location of the Ciliated Simple Columnar Epithelium
Lines some bronchioles (small tubes) of respiratory tract, uterine tubes, uterus, some paranasal sinuses, central canal of spinal cord, and ventricles of brain.
The following are the functions of this type of epithelium: In the respiratory tract, the cilia beat in unison, moving mucus and foreign particles toward throat, where they can be coughed up and swallowed or spit out. Coughing and sneezing speed up movement of cilia and mucus. Cilia also help move oocytes (immature ova) expelled from ovaries through uterine tubes into uterus.
Ciliated Simple Columnar Epithelium
appears to have several layers because the nuclei of the cells are at various levels. Even though all the cells are attached to the basement membrane in a single layer, some cells do not extend to the apical surface. When viewed from the side, these features give the false impression of a multilayered tissue. It also contains cells without cilia and also lacks globlet cells.
Nonciliated Pseudostratified Columnar Epithelium
Location of the Nonciliate Pseudostratified Columnar Epithelium
Lines epididymis, larger ducts of many glands, and parts of male urethra.
Its function is also absorption and secretion
Nonciliated Pseudostratified Columnar Epithelium
appears to have several layers because cell nuclei are at various levels. All cells are attached to basement membrane in a single layer, but some cells do not extend to apical surface. When viewed from side, these features give false impression of a multilayered tissue. Contains cells that extend to surface and secrete mucus (globlet cells) or bear cilia.
Ciliated Pseudostratified Columnar Epithelium
Location of Ciliated Pseudostratified Columnar Epithelium
Lines airways of most of upper respiratory tract.
Its function is that it secretes mucus that traps foreign particles, and cilia sweep away mucus for elimination from body.
Ciliated Pseudostratified Columnar Epithelium
has two or more layers of cells; cells in apical layer and several layers deep to it are squamous; cells in deeper layers vary from cuboidal to columnar. As basal cells divide, daughter cells arising from cell divisions push upward toward apical layer. As they move toward surface and away from blood supply in underlying connective tissue, they become dehydrated and less metabolically active. Tough proteins predominate as cytoplasm is reduced, and cells become tough, hard structures that eventually die. At apical layer, after dead cells lose cell junctions they are sloughed off, but they are replaced continuously as new cells emerge from basal cells.
Stratified Squamous Epithelium
develops tough layer of keratin in apical layer of cells and several layers deep to the apical layer
Keratinized stratified squamous epithelium
is a tough, fibrous intracellular protein that helps protect skin and underlying tissues from heat, microbes, and chemicals.
Keratin
Relative amount of keratin increases in cells as they move away from nutritive blood supply and organelles die.
Keratinized stratified squamous epithelium
does not contain large amounts of keratin in apical layer and several layers deep and is constantly moistened by mucus from salivary and mucous glands; surface cells do not die in this epithelium; instead, they are shed before they die.
Nonkeratinized stratified squamous epithelium
Location of the 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) and covers tongue.
Its function is for the protection against abrasion, water loss, ultraviolet radiation, and foreign invasion. Both types form first line of defense against microbes.
Stratified Squamous Epithelium
has two or more layers of cells; cells in apical layer are cube-shaped; fairly rare type.
Stratified Cuboidal Epithelium
Location of the Stratified Cuboidal Epithelium
Ducts of adult sweat glands and esophageal glands, part of male urethra.
Its function is for protection; limited secretion and absorption
Stratified Cuboidal Epithelium
usually consist of shortened, irregularly shaped cells; only apical layer has columnar cells; uncommon.
Stratified Columnar Epithelium
Location of the Stratified Columnar Epithelium
Lines part of urethra; large excretory ducts of some glands, such as esophageal glands; small areas in anal mucous membrane; part of conjunctiva of eye.
Its function is for protection and secretion
Stratified Columnar Epithelium
has a variable appearance (transitional) and is unique to the urinary system. In relaxed or unstretched state, looks like stratified cuboidal epithelium, except apical layer cells tend to be large and rounded. As tissue is stretched, cells become flatter, giving the appearance of stratified squamous epithelium. Multiple layers and elasticity make it ideal for lining hollow structures (urinary bladder) subject to expansion from within.
Urothelium
Location of the Urothelium
Lines urinary bladder, ureters, and portions of urethra.
Its function is it allows urinary organs to stretch and maintain protective lining while holding variable amounts of fluid without rupturing
Urothelium
also called a Pap test or Pap smear, involves collection and microscopic examination of epithelial cells that have been scraped off the apical layer of a tissue.
Papanicolaou test
A very common type of Pap test involves examining the cells from the nonkeratinized stratified squamous epithelium of the ___ (inferior portion) of the uterus. This type of Pap test is performed mainly to detect early changes in the cells of the female reproductive system that may indicate a precancerous condition or cancer.
cervix
It is recommended that Pap tests should be performed every three years beginning at age ___
21
It is further recommended that females aged ___ should have Pap testing and HPV (human papillomavirus) testing (cotesting) every five years or a Pap test alone every three years.
30 to 65
The function of ___ is secretion, which is accomplished by glandular cells that often lie in clusters deep to the surface epithelium.
Glandular Epithelium
consists of epithelium that secretes substances into ducts (tubes), onto a surface, or eventually into the blood in the absence of ducts. All glands of the body are classified as either endocrine or exocrine.
Gland
The secretions of ___ called hormones, enter the interstitial fluid and then diffuse into the bloodstream without flowing through a duct. They also have far-reaching effects because they are distributed throughout the body by the bloodstream.
Endocrine Glands
The word endo- means
inside
The word -crine means
secretion
secrete their products into ducts that empty onto an epithelium that covers or lines a surface, such as the skin surface or the lumen of a hollow organ. Their secretions also have limited effects and some of them would be harmful if they entered the bloodstream.
Exocrine Glands
The word exo- means
outside
secretions (hormones) enter interstitial fluid and then diffuse into bloodstream without flowing through a duct.
Endocrine Glands
Location of the endocrine glands
Examples include pituitary gland at base of brain, pineal gland in brain, thyroid and parathyroid glands near larynx (voice box), suprarenal (adrenal) glands superior to kidneys, pancreas near stomach, ovaries in pelvic cavity, testes in scrotum, thymus in thoracic cavity.
Its function is that its hormones regulate many metabolic and physiological activities to maintain homeostasis.
Endocrine Glands
secretory products are released into ducts that empty onto an epithelium that covers or lines a surface, such as skin surface or lumen of hollow organ
Exocrine Glands
Location of the exocrine glands
Sweat, oil, and earwax glands of skin; digestive glands such as salivary glands (secrete into mouth cavity) and pancreas (secretes into small intestine).
Its function is that it produce substances such as sweat to help lower body temperature, oil, earwax, saliva, or digestive enzymes
Exocrine Glands
Structural classification of multicellular exocrine glands is based on the
branching pattern of the duct and the shape of the secreting portion
What are the 2 structural classification of exocrine glands?
Unicellular and Multicellular Glands
are single-celled glands
Unicellular Glands
are important unicellular exocrine glands that secrete mucus directly onto the apical surface of a lining epithelium.
Goblet Cells
Most exocrine glands are ___, composed of many cells that form a distinctive microscopic structure or macroscopic organ.
Multicellular Glands
Examples of this type of glands include sudoriferous (sweat), sebaceous (oil), and salivary glands.
Multicellular Glands
Multicellular glands are categorized according to two criteria:
(1) whether their ducts are branched or unbranched and (2) the shape of the secretory portions of the gland
If the duct of the gland does not branch, it is a
simple gland
If the duct branches, it is a
compound gland
Glands with tubular secretory parts are
tubular glands
Those with rounded secretory portions are
acinar glands or alveolar glands
The word acin- means
berry
have both tubular and more rounded secretory parts
Tubuloacinar glands
Classification scheme for multicellular exocrine glands are the
Simple and Compound Glands
What are the 5 types of simple glands?
Simple tubular, simple branched tubular, simple coiled tubular, simple acinar, and simple branched acinar.
What are the 3 types of compound glands?
Compound tubular, compound acinar, and compound tubuloacinar
Tubular secretory part is straight and attaches to a single unbranched duct
Simple tubular
Example of simple tubular
glands in the large intestine
Tubular secretory part is branched and attaches to a single unbranched duct
simple branched tubular
Example of simple branched tubular
gastric glands
Tubular secretory part is coiled and attaches to a single unbranched duct
Simple coiled tubular
Example of simple coiled tubular
sweat glands
Secretory portion is rounded, attaches to single unbranched duct
Simple acinar
Example of simple acinar
glands of spongy urethra
Rounded secretory part is branched and attaches to a single unbranched duct
Simple branched acinar
Example of simple branched acinar
sebaceous glands
Secretory portion is tubular and attaches to a branched duct
Compound tubular
Example of compound tubular
bulbourethral glands
Secretory portion is rounded and attaches to a branched duct
Compound Acinar
Example of compound acinar
mammary glands
Secretory portion is both tubular and rounded and attaches to a branched duct
Compound tubuloacinar
Example of compound tubuloacinar
acinar glands of the pancreas
The functional classification of exocrine glands is based on
how their secretions are released
Each of these secretory processes begins with the ___ and ___ working together to form intracellular secretory vesicles that contain the secretory product.
endoplasmic reticulum; golgi complex
Secretions of ___ are synthesized on ribosomes attached to rough ER; processed, sorted, and packaged by the Golgi complex; and released from the cell in secretory vesicles via exocytosis
merocrine glands
The word mero- means
a part
Most exocrine glands of the body are ___.
merocrine glands
Examples of merocrine glands include
salivary glands and pancreas
accumulate their secretory product at the apical surface of the secreting cell. Then, that portion of the cell pinches off by exocytosis from the rest of the cell to release the secretion
Apocrine sweat glands
The word apo- means
from
Electron microscopy has confirmed that this is the mechanism of secretion of milk fats in the mammary glands.
Apocrine sweat glands
The cells of ___ accumulate a secretory product in their cytosol. As the secretory cell matures, it ruptures and becomes the secretory product. Because the cell ruptures in this mode of secretion, the secretion contains large amounts of lipids from the plasma membrane and intracellular membranes. The sloughed-off cell is replaced by a new cell.
Holocrine glands
The word holo- means
entire
Example of a holocrine glands is a
sebaceous gland of the skin
The functional classification of exocrine glands is based on
whether a secretion is a product of a cell or consists of an entire or a partial glandular cell.
is one of the most abundant and widely distributed tissues in the body.
connective tissue
It binds together, supports, and strengthens other body tissues; protects and insulates internal organs; compartmentalizes structures such as skeletal muscles; serves as the major transport system within the body (blood, a liquid connective tissue); contains and distributes almost all the blood vessels in the body; is the primary location of stored energy reserves (adipose, or fat, tissue); and is the main source of immune responses.
Connective tissue
Connective tissue consists of two basic elements
Extracellular matrix and cells
is the material located between its widely spaced cells.
Extracellular matrix
The extracellular matrix consists of ___ and ___, the material between the cells and the fibers.
protein fibers; ground substance
are secreted by the connective tissue cells and account for many of the functional properties of the tissue in addition to controlling the surrounding watery environment via specific proteoglycan molecules
extracellular fibers
determines much of the tissue’s qualities. For instance, in cartilage, the extracellular matrix is firm but pliable. The extracellular matrix of bone, by contrast, is hard and inflexible.
extracellular matrix
Unlike epithelial tissue, ___ usually is highly vascular; that is, it has a rich blood supply.
connective tissue
Except for cartilage, connective tissue, like epithelial tissue, is supplied with ___
nerves
Embryonic cells called ___ give rise to the cells of connective tissue.
mesenchymal cells
Each major type of connective tissue contains an immature class of cells with a name ending in ___, which means “to bud or sprout.”
-blast
These immature cells are called ____ in loose and dense connective tissue, ___ in cartilage, and ___ in bone
fibroblasts; chondroblasts; osteoblasts
retain the capacity for cell division and secrete the extracellular matrix that is characteristic of the tissue.
Blast cells
In some connective tissues, once the extracellular matrix is produced, the immature cells differentiate into mature cells with names ending in -cyte, namely, ___, ___, and ___.
fibrocytes; chondrocytes; osteocytes
have reduced capacities for cell division and extracellular matrix formation and are mostly involved in monitoring and maintaining the extracellular matrix.
Mature cells
Connective tissue cells vary according to the type of tissue and include the following
Fibroblasts, Macrophages, Plasmocytes, Mast cells, Adipocytes, and Leukocytes
are large, flat cells with branching processes. They are present in all the general connective tissues, and usually are the most numerous.
Fibroblasts
The word fibro- means
fibers
are phagocytes that develop from monocytes, a type of white blood cell.
Macrophages
reside in a particular tissue; examples include alveolar macrophages in the lungs and splenic macrophages in the spleen.
Resting macrophages
have the ability to move throughout the tissue and gather at sites of infection or inflammation to carry on phagocytosis.
Wandering macrophages
The word macro- means
large
The word -phages means
eaters
are found in many places in the body, but most plasmocytes reside in connective tissue, especially in the digestive canal and respiratory tracts.
Plasmocytes or plasma cells
are involved in the inflammatory response, the body’s reaction to injury or infection, and can also bind to, ingest, and kill bacteria.
Mast cells or mastocytes
are fat cells or adipose cells, connective tissue cells that store triglycerides (fats). They are found deep to the skin and around organs such as the heart and kidneys.
Adipocytes
are not found in significant numbers in normal connective tissue. However, in response to certain conditions they migrate from blood into connective tissue. For example, neutrophils gather at sites of infection, and eosinophils migrate to sites of parasitic invasions and allergic responses.
Leukocytes
The extracellular matrix consists of two major components:
(1) the ground substance and (2) the fibers
are usually the most numerous connective tissue cells.
Fibroblasts
are made of collagen and glycoproteins. They provide support in blood vessel walls and form branching networks around various cells (fat, smooth muscle, nerve).
Reticular fibers
are large flat cells that move through connective tissue and secrete fibers and ground substance.
Fibroblasts
are strong, flexible bundles of the protein collagen, the most abundant protein in your body.
Collagen Fibers
are abundant along blood vessels. They produce histamine, which dilates small blood vessels during inflammation and kills bacteria.
Mast Cells
develop from B lymphocytes. They secrete antibodies that attack and neutralize foreign substances.
Plasmocytes
is the material between cells and fibers. It is made of water and organic molecules (hyaluronic acid, chondroitin sulfate, glucosamine). It supports cells and fibers, binds them together, and provides a medium for exchanging substances between blood and cells.
Ground substance
are white blood cells that migrate to sites of infection that destroy microbes by phagocytosis.
Neutrophils
are white blood cells that migrate to sites of parasitic infection and allergic responses.
Eosinophils
are fat cells that store fats.They are found below the skin and around organs(heart, kidney).
Adipocytes
are stretchable but strong fibers made of proteins, elastin, and fibrillin. They are found in skin, blood vessels, and lung tissue.
Elastic fibers
develop from monocytes and destroy bacteria and cell debris by phagocytosis.
Macrophages
is the component of a connective tissue between the cells and fibers.
Ground substance
may be fluid, semifluid, gelatinous, or calcified. It supports cells, binds them together, stores water, and provides a medium for exchange of substances between the blood and cells. It plays an active role in how tissues develop, migrate, proliferate, and change shape, and in how they carry out their metabolic functions.
Ground substance
___ contains water and an assortment of large organic molecules, many of which are complex combinations of polysaccharides and proteins. The polysaccharides include hyaluronic acid, chondroitin sulfate, dermatan sulfate, and keratan sulfate. Collectively, they are referred to as ___
Ground substance; glycosaminoglycans (GAGs)
Except for hyaluronic acid, the GAGs are associated with proteins called
proteoglycans
form a core protein and the GAGs project from the protein like the bristles of a brush.
proteoglycans
One of the most important properties of ___ is that they trap water, making the ground substance more jellylike.
Glycosaminoglycans (GAGs)
