Anatomy and Physiology Chapter 4: The tissue level of organization

1. Name the four basic types of tissue that make up the human body and state the characteristics of each.
What is tissue?
A group of cells that usually have a common embryonic origin and function together to carry out specialized activities.
What is histology?
The science that deals with the study of tissue and disease.
What is a pathologist?
A person who specializes in laboratory studies of cells and tissues to help other physicians make accurate diagnoses.
What is epithelial tissue?
Covers body surfaces and lines hollow organs, body cavities, and ducts. It also forms glands.
What is connective tissue?
Protects and supports the body and its organs. Various types of connective tissue bind organs together, stores energy reserves as fat and helps provide immunity to disease-causing organisms. All connective tissue and most muscle tissues derive from mesoderm.
What is muscular tissue?
Generates the physical force needed to make body structures move and generate body heat. All connective tissue and most muscle tissues derive from mesoderm.
What is nervous tissue?
Detects changes in a variety of conditions inside and outside the body and responds by generating action potentials (nerve impulses) that activate muscular contractions and glandular secretions. Nervous tissues develop from the ectoderm.
What are the four basic types of tissue?
1. Epithelial
2. Connective
3. Muscular Tissue
4. Nervous Tissue
What is the primary germ layer?
One of three layers of embryonic tissue, called ectoderm, mesoderm, and endoderm, that give rise to all tissues and organs of the body.
Describe the structure and functions of the five mains types of cell junctions?
What are cell junctions and what are the 5 types of cell junctions?
Cell Junctions are contact points between the plasma membrane of tissue cells.
1. Tight junctions
2. Adherens Junctions
3. Desmosomes
4. Hemidesmosomes
5. Gap Junctions
What are tight junctions?
Consist of weblike strands of transmembrane proteins that fuse the outer surfaces of adjacent plamsa membrane
What are adherens junctions?
Adherens junctions contains 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.
Name two components of the adherens junction and their function.
1. Cadherins: Transmembrane glycoproteins that join the cell.
2. Adhesion Belts: They encircle the cell similar to the way a belt encircles your waist.
What are desmosomes?
Desmo-band: Contain plaque and have transmembrane glycoproetins (cadherins) that extend into the intercellular space between adjacent cell membranes and attach cells to one another. Unlike adherens juctions, the plaque of desosomes does not attach to microfilaments. Instead a desosome plaque attaches to elements of the cytoskeleton.
What are hemidesmosomes?
Hemi=half: Resemble desmosomes but they do not link adjacent cells. Their transmembrane glcopreteins are called integrins not cadherins. On the inside of the plasm membrane, inegrins attache to intermediate filaments made of the protein keratin. One the outside of the plasma membrane the integrins attach to the protein laminin. Which is present in the basement membrane.
What are gap junctions?
Membrane proteins called connexins form tiny fluid-filled tunnels called connexons that connect neighboring cells. The plasma membranes of gap junctions are not fused together as in ight junctions but are separated by a very narrow intercellular gap (space).
1. Describe the general features of epithelial tissue?
2. List the location, structure, and function of each different type of eipithelium.
Describe what epithelial tissue consists of
Consists of cells arranged in continuous sheets, in either single or multiple layers. Because the cells are closely packed together by many cell junctions, there is little intercellular space between adjacent plasma membranes.
What are the three major function of epithelial tissue?
1. Selective barriers that limit or aid the transfer of substances into and out of the body.
2. Secretory surfaces that release products produced by the cells onto their free surfaces.
3. Protective surfaces that resist the abrasive influences of the environment.
Describe the apical free surface of an epithelial cell.
The apical (free) surface of an epithelial cell faces the body surface, a body cavity, the lumen (interior space) of an internal organ, or a tubular duct that receives cell secretions. Apical surfaces may contain cilia or microvilli.
Apical and basal refer to:
Apical refers to the most superficial layer of the cell. Basal is the deepest layer of epithelial cells.
What two layers does the basement membrane consist of?
1. the basal lamina
2. reticular lamina (lamina=thin layer)
The basement membrane functions as a point of attachment and support for the overlying epithelial tissue.
Describe the epithelial tissue blood and nerve supply.
Epithelial tissue is avasuclar (a=without, vasuclar=vessel). It has its own nerve supply but lacks its own blood supply. Exchange of substances between epitheliuma nd connective tissue occurs by diffusion.
Epithelial tissue is divided into what two types?
1. Covering and lining: Forms the outer covering of the skin and some internal organs.
2. Glandular epithelium: Makes up the secreting portion of glands such as the thyroid gland, adrenal glands and sweat glands.
What are the three types of cells in layers?
1. Simple epithelium
2. Pseudostratified epithelium
3. Stratified epithelium
What is simple epithelium?
The cells are arranged in one or more layers depending on the function the epithelium performs:
What is pseudostratified epithelium?
pseudo=false: Appears to have multiple layers of cells because the cell nucleoli lie at different levels and not all cells reach the apical surface.
What is stratified epithelium?
Consists of two or more layers of cells that protect underlying tissues in locations where there is considerable wear and tear.
What are the four types of cell shapes?
1. SQUAMOUS CELLS: Arranged like floor tiles and are thin, which allow for the rapid passage of substances.
2. CUBOIDAL CELLS: Tall as they are wide and are shaped like cubes or hexagons.
3. COLUMNAR CELLS: Much taller than they are wide like columns, and protect underlying tissues Their apical surfaces may have cilia or microvilli. Often they are specialized for secretion and absorption.
4. TRANSITIONAL CELLS: Change shape, from flat to cuboidal and back, as organs such as the urinary bladder stretch (distend) to larger size and then collapse to a smaller size.
Describe, location, and function of simple squamous epithelium.
Description: Single layer of flat cells, centrally located nucleus.
Location: Lines heart, blood vessels, lymphatic walls, air sacs of lungs, globular (Bowman's) capsule of kidneys, and inner surface of the tympanic membrane (eardrum); forms epithelial layer of serous membranes (mesothelium), such as the peritoneum, pericardium, and pleura.
Function: Filtration, diffusion, osmosis, and secretion in serous membranes.
Describe, location, and function of cuboidal epithelium.
Description: Single layer of cube-shaped cells; centrally located nucleus.
Location: 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, lines kidney tubules and smaller ducts of many glands, and makes up the secreting portion of some glands such as the thyroid gland and the ducts of some glands such as the pancreas.
Function: Secretion and absorption.
Describe location, and function of nonciliated simple columnar epithelium
Description Single layer of nonciliated column-like cells with nuclei near base of cells; contains gobble cells and cells with microvilli in some locations.
Location: Lines the gastointestinal tract (from the stomach to the anus), ducts of many glands, and gallbladder.
Function: Secretion and absorption
Describe location, and function of ciliated simple columnar epithelium.
Description: Single layer of ciliated column-like cells with nuclei near base; contains goblet cells in some locations.
Location: Lines some bronchioles (small tubes) of respiratory tract, uterine (fallopian) tubes, uterus, efferent ducts of the testes, some paranasal sinuses, central canal of spinal cord, and ventricles of the brain.
Function: Move mucus and other substances by ciliary acton.
Describe location and function of pseudostratified columnar epithelium.
Description: 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.
Location: Pseudostratified ciliated columnar epithelium lines the airways of most upper respiratory tract; pseudostratified nonciliated columnar epithelium lines larger duct of many glands, epididymis, and part of the male urethra.
Function: Secretion and movement of mucus by ciliary action (ciliated); absorption and protection (non ciliated)
Describe squamous epithelium.
Description: Several layers of cells; cuboidal to columnar shape in deep layers; squamous cells form the apical layer and several layers deep to it; cells from the basal layer replace surface cells as they are lost.
Location: Keratiniezed variety forms superficial layer of skin; nonkeratinized variety lines wet suffices, such as lining of the mouth, esophagus, part of larynx, part of pharynx, and vagina, and covers the tongue.
Function: Protection
Describe stratified cuboidal epithelium.
Description: Two or more layers of cells in which the cells in the apical layer are cube shaped.
Location: Ducts of adult sweat glands and esophageal glands and part of the male urethra.
Function: Protection and limited secretion and absorption.
Describe stratified columnar epithelium.
Description: Several layers of irregularly shaped cells; only the apical layer has columnar cells
Location: Lines part of urethra, large excretory ducts of some glands, such as esophageal glands, small areas n anal mucous membrane and part of the conjunctiva of the eye.
Function: Protection and secretion.
Describe transitional epithelium
Description: Appearance is variable (transitional); shape of cells in apical layer ranges form squamous (when stretched to cuboidal (when relaxed).
Location: Lines urinary bladder and portions of ureters and urethra
Function: Permits distension
Describe endocrine glands versus exocrine glands.
Endo=inside; crine=secretion; exo=outside; crine=secretion.....Endocrine glands enter interstitial fluid and diffuse directly into bloodstream. Exocrine glands secrete products into ducts that empty on the skin surface or lumen of a hollow organ.
Describe the endocrine glands of glandular epithelium.
Description: Secretory products (hormones) diffuse into blood after passing through interstitial fluid.
Location: Examples include pituitary gland at base of brain, pineal gland in braid, thyroid and parathyroid glands near larynx (voice box), adrenal glands superior to kidneys, pancreas near stomach, ovaries in pelvic cavity, testes in scrotum, and thymus in thoracic cavity.
Function: Produce hormones that regulate various body cavities.
Describe the exocrine glands of glandular epithelium.
Description: Secretory products released into ducts.
Location: Sweat, oil, and earwax glands of the skin; digestive glands such as salivary glands, which secrete into mouth cavity, and pancreas, which secretes into the small intestine.
Function: Produce substances such as sweat, oil, earwax, saliva, or digestive enzymes.
Name the simple glands:
1. Simple tubular
2. Simple branched tubular
3. Simple coiled tubular
4. Simple acinar
5. Simple branched acinar
Describe a simple tubular gland.
Tubular secretory part is "STRAIGHT" and attaches to a single unbranched duct. Examples: glands in large intestine
Describe a simple branched tubular gland.
Tubular secretory part is branched and attaches to a single unbranched duct.
Describe a simple coiled tubular gland.
Tubular secretory part is coiled and attaches to a single unbranched duct.
Describe a simple acinar gland.
Acin=berry: Secretory portion is "ROUNDED" and attached to a single unbranched duct.
Describe a simple branched acinar gland.
Rounded secretory part is branched and attaches to a single unbranched duct.
Name the compound glands:
1. Compound tubular
2. Compound acinar
3. Compound tubuloacinar
Describe a compound tubular gland.
Secretory portion is "TUBULAR" and attaches to a "BRANCHED" duct. Example: bulbourethral (Cowpers) gland
Describe a compound acinar.
Secretory portin is rounded and attaches to branched duct. Example: mammary glands.
Describe a compound tubuloacinar gland.
Secretory portion is both tubular and round and attaches to a branched duct. Example: acinar glands of the pancreas.
1. Describe the general feature of connective tissue.
2. Describe the structure, location, and function of various types of connective tissue
What two basic elements are connective tissue composed of:
1. Extracellular matrix
2. Cells
What is extracellular matrix?
The material located between its widely spaced cells. the extracellular matrix consists of protein fibers and ground substance, the material between the cells and the fibers.
What does the suffix blast mean?
blast="to bud or spout" as in fibroblass which are immature cells in dense and loose connective tissue. Once immature cells differentiate into mature cells they are end in cyte.
Name some connective tissues cells.
1. Fibroblasts (fibro=fibers):
2. Adipocytes:
3. Mast Cells
4. White blood cells
5. Macrophages
6. Plasma Cells
What are fibroblasts?
Large, flat cells with branching processes. They are present in several connective tissues, and usally are the most numerous. Fibroblasts migrate through the connective tissue, secreting the fibers and certain components of the ground substance of the extracellular matrix.
What are adipocytes?
Also called fat cells or adipose cells are connective tissue cells that store triglycerides (fats). They are found deep to the skin and around organs such as the heart and kidneys.
What are mast cells?
Mass cells are abundant alongside the blood vessels that supply connective tissue. The produce histamine, a chemical that dilates small blood vessels as part of the inflammatory response, the body's reaction to injury or infection. In addition, researchers have recently discovered that mast cells can bind to, ingest, and kill bacteria.
What are white blood cells?
White blood cells are not found in significant numbers in normal connective tissue. However, in response to certain conditions they migrate from blood into connective tissues. For example, neutrophils gather at sites of infection, and eosinophils migrate to sites of parasitic invasions and allergic responses.
What are macrophages?
Macro=large, phates=eaters: develop from monocytes, a type of white blood cell. Macrophages have an irregular shape with short branching projections and are capable of engulfing bacteria and cellular debris by phagocytosis.
What are plasma cells?
Small cells that develop from a type of white blood cell called a B lymphocyte. Plasma cells secrete antibodies, proteins that attack or neutralize foreign substances in the body.
What two components does the extra-cellular matrix consist of?
1. Ground substance
2. Fibers
What is ground substance?
Component of a connective tissue between between the cells and fibers. Fibrobasts secrete the fibers and certain components of the ground substance.
Grounds substance contains an assortment of large organic molecules. Collectively theses are referred t as glycosaminoglycans or GAGs. What are the GAGs.
1. Hyaluronic acid
2. chondroitin sulfate,
3. dermatan sulfate
4. keratan sulfate
Describe each ground substance above and their function:
What are proteolglycans?
Adhesion proteins
What are the three types of fibers embedded in the extracellular matrix?
1. Collagen fibers
2. Elastic fibers
3. Reticular fibers
Describe collagen fibers
colla=glue: Very strong and resist pulling forces, but they are not stiff, which allows tissues flexibility.
Describe elastic fibers
Elastic fibers are smaller in diameter than collagen fibers, branch and join together to form a network within a tissue.
What are reticular fibers.
Reticul=net: Consists of collagen arranged in fine bundles with a coating of glycoprotein, provide support in the walls of blood vessels and form a network around the cells in some tissues, such as areolar connective tissue, adipose tissue, and smooth muscle tissue.
What are two types of embryonic connective tissues?
1. Mesenchme
2. Mucous Connective Tissue
Describe the description, location and function of mesenchme.
DESCRIPTION: Consists of irregularly shaped mesenchymal cells embedded in a semifluid ground substance that contains reticular fibers.
LOCATION: Under skin and along developing bones of embryo; some mesenchymal cells are found in adult connective tissue, especially along blood vessels.
FUNCTIONS: Forms all other types of connective tissue
Describe mucous connective tissue.
DESCRIPTION: Consists of widely scattered fibroblast embedded in a viscous, jellylike ground substance that contains the fine collagen fibers.
LOCATION: Umbilical cord of fetus
What are the 5 types of mature connective tissues?
1. Loose connective tissues
2. Dense connective tissues
3. Cartilage
4. Bone Tissue
5. Liquid Connective Tissue (Blood Tissue and Lymph)
There are 3 types of loose connective tissue what are they?
1. Areolar (areol=small space)
2. Adipose Tissue
3. Reticular Connective Tissue
Describe areolar tissue.
DESCRIPTION: Consists of fibers (collagen, elastic, and reticular) and several kinds of cells (fibroblasts, macrophages, plasma cells, adipocyte, and mast cells) embedded in a semifluid ground substance.
LOCATION: Subcutaneous layer deep to skin; papillary (superficial) region of dermis of skin; lamina propia of mucous membranes; and around blood vessels, nerves and body organs.
FUNCTION: Strength, elasticity and support
Describe Adipose Tissue.
DESCRIPTION: Consists of adipocytes, cells specialized to store triglycerides (fats) as a large centrally located droplet; nucleus and cytoplasm are peripherally located.
LOCATION: Subcutaneous layer deep to skin, around heart and kidneys, yellow bone marrow, and padding around joins and behind eyeball in eye socket
FUNCTION: Reduces heat loss through skin, serves as an energy reserve, supports, and protects. In newborns, brown adipose tissue generates considerable heat the helps maintain proper body temperature.
Describe reticular connective tissue.
DESCRIPTION: A network of interlacing reticular fibers and reticular cells.
LOCATION: Stroma (supporting framework) of liver, spleen, lymph nodes; red bone marrow, which gives rise to blood cells; reticular lamina of he basement membrane; and around blood vessels and muscles.
FUNCTION: Forms stroma of organs; binds together smooth muscle tissue cells; filters and removes worn-out blood cells in the spleen and microbes in lymph nodes.
What are the three types of dense connective tissues?
1. Dense Connective Tissue
2. Dense irregular connective tissue
3. Elastic Connective Tissue
Describe dense connective tissue.
DESCRIPTION: Extracellular matrix looks shiny white; consists mainly of collagen fibers regularly arranged in bundles; fibroblasts present in rows between bundles.
LOCATION: Forms tendons (attach muscle to bone), most ligaments (attach bone to bone), and aponeuroses (sheetlike tendons that attach muscle to muscle or muscle to bone).
FUNCTION: Provides strong attachment between various sources.
Describe dense irregular connective tissue.
DESCRIPTION: Consists predominantly of collagen fibers randomly arranged and a few fibroblasts
LOCATION: Faciae (tissue beneath skin and around muscles and other organs), reticular (deeper) region of dermis of skin, periosteum of bone, perichondrium of cartilage, joint capsules, membrane capsuels around various organs (kidneys, liver, testes, lymph nodes), pericardium of the heart and heart valves.
FUNCTION: Provides strength
Describe elastic connective tissue.
DESCRIPTION: Consists predominantly of elastic fibers; fibroblasts are present in spaces between fibers.
LOCATION: Lung tissue, walls of elastic arteries, trachea, bronchial tubes, true vocal cords, suspensory ligament of penis, and some ligaments between vertebrae.
FUNCTION: Allows stretching of various organs.
What is cartilage?
Cartilage consists of a dense network of collagen fibers or elastic fibers firmly embedded in chondroitin sulfate, a gell like component of ground substance. Cartilage can endure considerably more stress than loose and dense connective tissues. The strength of cartilage is due to is collagen fibers, and its resilience (ability to assume its original shape after deformation) is due to chondroitin sulfate.
What are the three types of cartilage?
1. Hyaline cartilage
2. Fibrocartilage
3. Elastic Cartilage
What are chondrocytes?
(Chrondo=cartilage). The cells of mature cartilage
What are lacunae?
(lakunae=little lakes). Spaces in the extracellular matrix.
What is antiangiogenesis factor?
(anti=against, angio=vessel, genesis=production)
Cartilage does not have a blood supply because it secretes an aniangiogenesis factor. Since cartilage has no blood supply it heals slowly.
What is perichondrium?
(Peri=around)=A covering of dense irregular connective tissue. Surrounds the surface of most cartilage.
The perichondrium is composed of what two layers?
1. An outer fibrous layer that consists of collagen fibers.
2. An inner cellular layers that consists of cells involved in growth of cartilage.
Describe hyaline cartilage.
DESCRIPTION: Consists of a bluish-white, shiny ground substance with thin, fine collagen fibers and may chondrocytes; most abundant type of cartilage.
LOCATION: Ends of long bones, anterior ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, and embryonic and fetal skeleton.
FUNCTION: Provides smooth surfaces for movements at joints, as well as flexibility and support.
Describe fibrocartilage
DESCRIPTION: Consists of chondrocytes scattered among thick bundles of collagen fibers within the exracellular matrix.
LOCATION: Public symphysis (point where hip bones join anteriorly), intervertebral discs (discs between vertebrae), menisci (cartilage pads) of knee, and portion of tendons that insert into cartilage.
FUNCTION: Support and fusion.
Describe elastic cartilage
DESCRIPTION: Consists of chodrocytes located ina threadlike network of elastic fibers within the extracellular network.
LOCATION: Lid on top of larynx (epiglottis), part of external ear (auricle), and auditory (eustachian) tubes.
FUNCTION: Gives support and maintains shape.
The growth of cartilage consists of what two basic patterns?
1. Interstitial growth.
2. Appositional growth.
What is interstitial growth?
Interstitial growth is growth from within a tissue.
This pattern is occurs while the cartilage is young and pliable, during childhood and adolescence.
What is appositional growth?
Appositional growth is growth at the outer surface of the tissue. Appositional growth starts later than interstitial growth and continues through adolescence.
What are the basic units of compact bone?
1. Osteon and haversian system.
What are the four parts of the osteon?
1. The lamellae
2. The lacunae
3. The canaliculi
4. A central (haversian) canal
What are the lamellae?
Concentric rings of extracellular matix that consist of mineral salts (mostly calcium and phosphates), which give bone its harness, and collagen fibers, which give bones its strength.
What is lucanae?
Small spaces between lamellae that contain mature bone cell called osteocytes.
What is canaliculi?
Networks of minute canals containing the processes of osteocytes. Canaliculli provide routes for nutrients to reach osteocytes and for wastes to leave them.
What is a central canal?
Contains blood vessels and nerves
What are two type of liquid connective tissue?
1. Blood tissue (or simply blood): Connective tissue with a liquid extracellular matrix called blood plasma.
2. Lymph: Extracellular fluid that flows in lymphatic vessels.
What is blood plasma?
A pale yellow fluid that consists mostly of water with a wide variety of dissolved substances--nutrients, wastes, enzymes, plasma proteins, hormones, respiratory gases, and ions.
What is lymph?
Extracellular fluid that flows in lymphatic vessels.
1. Define a membrane
2. Describe the classification of membranes
What is a membrane?
They are flat sheets of pliable tissue that cover or line a part of the body. The combination of an epithelial layer and an underlying connective tissue constitutes and epithelial membrane.
What is a synovial membrane?
Lines joints and contains connective tissue but no epithelium.
What is an epithelial membrane?
It consists of a epithelial layer and an underlying connective tissue.
What the three types of epithelial membranes?
1. A mucous membrane
2. A serous membrane
3. A cutaneous membrane
What is a mucous membrane or mucosa?
A mucous membrane lines a body cavity that opens directly to the exterior. Mucous membranes line the entire digestive, respiratory, and reproductive tract, and much of the urinary tract.
What is the serous membrane or serosa?
Serous =watery; Lines a body cavity (thoracic and abdominal) that does not open directly to the exterior, and it covers the organs that lie within the cavity.
What ere the two layers to the serous membrane?
1. Parietel Layer (pariet=wall): The layer attached to and lining the cavity wall.
2. Visceral layer (viscer=body organ): The layer that covers and adheres to organs within the cavity walls.
What is the pleura?
The serous membrane lining the thoracic cavity and lining the lungs.
What is the pericardium?
The serous membrane lining the heart cavity and covering the pericardium.
What is the peritoneum?
The serous membrane lining the abdominal cavity and covering the abdominal organs.
What is the cutaneous membrane or skin?
Covers the entire surface of the body and consists of a superficial portion called the epidermis and a deeper portion called the dermis.
What are synovial membranes?
(syn=together), (ova=egg): Because it resemble the slimy egg white of an uncooked egg. The synovial cavities line the cavities of freely movable joints. Synovial membranes line structures that do not open to the exterior.
What are synoviocytes?
Membranes composed of a discontinuous layer of cells.
What is synovial fluid?
Lubricates and nourishes the cartilage covering the bones at movable joints and contains macrophages the remove microbes and debris from the joint cavity.
1. Describe the general feature of muscular tissue.
2. Contrast the structure, location, and mode of control of skeletal, cardiac, and smooth muscle cell.
What is muscular tissue?
Muscular tissue consists of elongated cells called muscle fiber or myocytes that can use ATP to generate force.
Describe skeletal muscle tissue.
DESCRIPTION: Long, cylindrical striated fibers with many peripherally located nuclei; "VOLUNTARY" control.
LOCATION: Usually attached to bones by tendons
FUNCTION: Motion, posture, heat production, and protection.
Describe Cardiac muscle tissue
DESCRIPTION: Branched striated fibers with on or two centrally located nuclei; contains intercalated discs;" "INVOLUNTARY" control
LOCATION: Heart Wall
FUNCTION: Pumps blood to all parts of the body.
Describe smooth muscle tissue
DESCRIPTION: Spindle-shaped (thickest in middle and tapering at both ends), nonstriated fibers with one centrally located nucleus; "INVOLUNTARY" control.
LOCATION: Iris of the eyes, walls of hollow internal structures such as blood vessels, airways to the lungs, stomach, intestines, gallbladder, urinary bladder, and uterus.
FUNCTION: Motion (constriction of blood vessels and airways, propulsion of foods through gastrointestinal tract, contraction of urinary bladder and gallbladder).
Describe nervous tissue.
DESCRIPTION: Consists of neurons (nerve cells) and neurolglia. Neurons consist of a cell body and processes extending from the cell body (multiple dendrites(dendr=tree) and a single axon (axo=axis)). Neuroglia do not generate impulses but have other important supporting functions.
LOCATION: Nervous system
FUNCTION: Exhibits sensitivity to various types of stimuli, converts stimuli into nerve impulses (action potentials), and conducts nerve impulses to other neurons, muscle fibers, or glands.
1. Explain the concept of electrical excitability.
What is electrical excitability?
The ability to respond to certain stimuli by producing electrical signals such as action potentials. Because neurons and muscle fibers exhibit electrical excitability they are considered excitable cells.
1. Describe the role of tissue repair in restoring homeostasis.
What is tissue repair?
Tissue repair is the replacement of worn-out, damaged, or dead cells by healthy ones.
What is vital to tissue repair?
Good nutrition and blood circulation.
1. Describe the effects of aging on tissues.
The four types of tissues are?
1. Epithelial
2. Connective
3. Muscle
4. Nervous
Epithelial tissue tends to be classified according to two criteria
Arrangement of cells in layers, cell shape
Distinguish whether cardiac, smooth, and skeletal tissue can be voluntary or involuntary.
Distinguish which tissues are vascular and avascuclar.
Cardiac muscle-vascular
Compact bone-vascular
Stratified Squamous Epithelial-avascular
Skeletal Muscle-vascular
If the lining of an organ produces and releases mucas, which of the following would likely be found in the tissue lining the organ?
Goblet Cells-yes
Mast Cells-no
Why does damaged cartilage heal slowly?
Cartilage is avascular, so materials needed for repair must diffuse from surrounding tissue.
The type of exocrine gland that forms its secretory product and simply releases it from the cell by exocytosis is the
Mecrocrine gland
Tissue changes that occur with aging can be due to?
1. cross links between glucose and proteins-yes
2. a decrease in the amount of collagen fibers-yes
3. a decreased blood supply-yes
4. improper nutrition-yes
5. a higher cellular metabolic rate-no
What type of cell would be required for cells to communicate with one another?
1. Adherens Junction
2. Desmosome
3. Gap Junction-YES
4. Tight Junction
5. Hemidesmosome
Describe Simple Squamous Epithelium
Contains a single layer of flat cell; found in the body where filtration (kidney) or diffusion (lungs) are priority process
Describe keratinized stratified squamous epithelium
Found in the superficial part of skin; provides protection from heat, microbes, and chemicals
Describe transitional epithelium
Found in the urinary bladder contains cells that can change shape (stretch or relax)
Describe simple cuboidal epithelium
Contains cube-shaped cells functioning in secretion and absorption.
Describe ciliated simple columnar epithelium
Lines the upper respiratory tract and uterine tubes; wavelike motion of cilia propels materials through the lumen.
Describe nonciliated epithelium
Contains cells with microvilli and goblet cells; found in linings of the digestive, reproductive, and urinary tracts
Describe pseudostratified ciliated epithelium
Contains cells that are all attached to the basement membrane, although some do not reach the surface; those cells that do extend to the surface secrete mucus or contain cilia.
Describe stratified cuboidal epithelium
A fairly rater type of epithelium that has mainly protective function
Label E for epithelial tissue
C for connective tissue
M for muscle tissue
N for nervous tissue
-binds, supports
-contains elongated cells that generate force
-may contain fibroblasts
-tightly packed cells
-intercalated discs
-goblet cells
-contains extracellular matrix
-generate action potentials
-ground substance
-apical surface
-binds, supports-C
-contains elongated cells that generate force-M
-may contain fibroblasts-C
-tightly packed cells-E
-intercalated discs-M
-goblet cells-E
-contains extracellular matrix-C
-generate action potentials-N
-ground substance-C
-apical surface-E
-excitable-N and M
Describe mesenchyme
The tissue from which all other connective tissues eventually arise
Describe lymph
Connective tissue with a clear, liquid matrx that flows in lymphatic vessels
Describe areolar connective tissue
Connectie tissue consisting of several kinds of cells, containing all three fiber types randomly arranged and found in the subcutaneous layer deep to the skin
Describe adipose tissue
A loose connective tissue specialized for triglyceride storage
Describe reticular connective tissue
Tissues that contain reticular fibers and reticular cells and forms the stroma of certain organs such as the spleen
Dense irregular connective tissue
Tissue with irregularly arranged collagen fibers found in the dermis of the skin
Describe elastic connective tissue
Tissue found in the lungs that is strong and can recoiled back to its original shape after being stretched
Describe hyaline cartilage
Tissue that affords flexibility at joints and reduces joint friction
Describe fibrocartilage
Tissue that provides strength and rigidity and is the strongest of the the three types of cartilage
Describe dense regular connective tissue
Bundles of collagen arranged in parallel patterns; compose tendons and ligaments
Describe bone (osseous tissue)
Tissue that forms the internal framework of the body and works with skeletal muscle to generate movement
Describe elastic cartilage
Tissue that contains a network of elastic fibers, providing strength, elasticity, and maintenance of shape; located in the external ear
Describe blood
Connective tissue with formed elements suspend in a liquid matrix called plasma
Which type of cell functions in communication between basement cells?
Gap junctions allow cellular communication via passage of electrical and chemical signals between adjacent cells.
What is the function of the basement membrane?
The basement membrane provides physical support for the epithelium.
Which cell type is best adapted for the rapid movement of substances from one cell to another?
Substances would move most rapidly through squamous cells because they are so thin.
What types of glands are sebaceous (oil) glands? Salivary glands?
Subaceous (oil) glands are holocrine glands, and salivary glands are merocrine glands
What is the function of fibroblasts?
Fibroblasts secrete the fibers and ground substance of the extracellular matrix.