Tissues/Histology, Ch. 4
Connective Tissue is divided into classes. One of these classes is Connective tissue proper. List the sub classes of this class and explain what tissues each sub class is subdivided into
Loose connective tissue; areolar, adipose, and reticular. Dense connective tissue; regular, irregular, and elastic
Explain what the matrix of a connective tissue is and what two parts comprise it
MATRIX: Connective tissue matrix is composed of: ground substance and fibers. Ground substance In ordinary connective tissue, the ground substance consists of water stabilized by glycosaminoglycans, proteoglycans, and glycoproteins. In bone the ground substance includes minerals. In blood, the ground substance is fluid (plasma). Fibers The principal fiber type is collagen -- the most abundant protein in the body -- which confers tensile strength with flexibility. Elastic fibers confer resiliency. The matrix is produced by fibroblasts (or related cell types -- chondroblasts in cartilage and osteoblasts in bone).
Describe and name the three basic common shapes of endothelial cells
Squamous cells are flattened and scalelike (squale= scale) Cuboidal cells are boxlike, approximately as tall as they are wide. Columnar cells are tall and column shaped.
Explain why tissue specimens must be "stained"
Staining: Most biological material is transparent and needs staining to increase the contrast between different structures. Different stains are used for different types of tissues. Methylene blue is often used for animal cells, while iodine in KI solution is used for plant tissues.
Simple squamous, simple cuboidal, simple columnar, pseudostratified, stratified squamous, stratified cubodial, stratified columnar, and transitional epithelium. Describe the morphology (shape/appearance) of the mentioned tissues
(Simple squamous epithelium) flattened laterally, resemble tiled floor, and resemble fried eggs. Thin and often permeable, simple squamous epithelium is found where filtration or the exchange of substances by rapid diffusion is a priority. In the kidneys, forms part of the filtration membrane. In the lungs, it forms the walls of the air sacs across which gas exchange occur (simple cubodial epithelium) consist of a single layer of cells as tall as they are wide. Important functions are secretion and absorption. This epithelium forms the walls of the smallest ducts of glands and of many kidney tubules. simple columnar epithelium is a single layer of tall, closely packed cells, aligned like soldiers in a row. It lines the digestive tract from the stomach through the rectum. Columnar cells are mostly associated with absorption and secretion. Dense microvilli = absorptive cells Tubular glands = secrete mucus containing intestinal juice. pseudostratified columnar epithelium all of its cells rest in the basement, vary in height, but only the tallest reach the free surface of the epithelium. The tissue give a false impression because of the nuclei lie at different levels above the basement membrane. Secretes or absorbs substances. found in the Trachea, lines mosth of the lines in the respiratory tract, traps mucus, and prevents it from getting into the lungs. stratified squamous epithelium composed of several layers, it is thick and well suited for its protective role in the body. This epithelium forms the external part of the skin and extends a short distance into every body opening that is directly continous with the skin. Protects underlying tissue in areas subjected to abrasion. located in moist linings of the esophagus, mouth, and vagina. The Keratinized (karitin) forms the epidermis of the body. Stratified Cuboidal epithelium rare in the body, mostly found in the ducts of some of the layer glands (sweat glands, mammary glands) typically has two layers of cuboidal cells. Stratified Columnar epithelium found in the pharynx, the male urethra, and lining some glandular ducts. transitional epithelium stretches readily, permits stored urine to distend urinary gland. lines the ureters, bladder, and part of the urethra. resembles both stratified squamous and stratified cuboidal
Describe the major functions of connective tissue
1) Binding and support 2) Protection 3) Insulation 4) Transportation of substances within body
State the percentage of fat found in a normal person, and a morbidly obese person
18% of an average persons body weight, and 50% of a morbidly obese person...
Describe the three main elements of connective tissue
Although connective tissue exists in a number of forms, all types have three basic structural elements -- cells, fibres and intercellular substance
Describe what is meant by the term polarity using the words "apical and basal surface"
Apical surface, an upper free surface exposed to the body exterior (or the cavity of an internal organ) and the lower attached is the basal surface.. The two differ in both structure and function. For this reason, we say that epithelia exhibit "apical-basal polarity"
Describe the general, obvious structural features of areolar connective tissue and explain what the word areolar means
Areola means "a small open space" The most obvious structural feature of this tissue is the loose arrangement of its fibers.
Explain what kind of cells are found in the matrix of cartilage
Cartilage is usually found in close association with bone in the body. It is a type of connective tissue which is tough, semi-transparent, elastic and flexible. The matrix or ground substance of cartilage consists mainly of glyco-protein material, chondroitin. The cartilage cells (chondrocytes) lie scattered in the matrix. Cartilage is covered by a dense fibrous membrane, the perichondrium. No nerves or blood vessels occur in cartilage.
Explain the difference between fixed and wandering cells
Connective tissue cells are typically divided into two types, fixed cells and wandering cells. Fibrocytes, or fibroblasts and fat cells(adipocytes) are fixed cells, where as macrophages, monocytes, lymphocytes, plasma cells, eosinophils and mast cells are wandering cells. Fibrocytes are the most common cell type in connective tissues. If fibrocytes are stimulated by damage to the surrounding tissue, the fibrocyte is altered into a fibroblast. The fibroblasts contain organelles that are necessary for the synthesis and excretion of proteins needed to repair the tissue damage. Fibrocytes usually do not leave the connective tissue. Reticular cells are usually larger than fibrocytes. Reticular cells are the fibrocytes of reticular connective tissue and form a network of reticular fibers. Adipocytes are fat cells that are fixed cells in loose connective tissue. Their main function is the storage of lipid. Macrophages arise from monocytes. Monocytes originate in the bone marrow upon which they are released into the blood stream. They are mobile and leave the blood stream to enter connective tissues where they differentiate into marcophages. The fibroblasts are the most important in the connective tissue. Fibroblasts manufacture and maintain the extracellular material. They migrate throughout the extracellular matrix to wherever they are needed. Adipocytes are cells that are very efficient at storing energy in the form of triglycerides.[3]
List the four main classes of connective tissue
Connective tissue proper, cartilage, bone tissue , blood
Describe what kind of fibers dense connective elastic tissue have
Dense connective tissue, also called dense fibrous tissue, has fibers as its main matrix element.[1] Dense connective tissue is mainly composed of collagen type I. Crowded between the collagen fibers are rows of fibroblasts, fiber-forming cells, that manufacture the fibers. Dense connective tissue forms strong, rope-like structures such as tendons and ligaments. Tendons attach skeletal muscles to bones; ligaments connect bones to bones at joints. Ligaments are more stretchy and contain more elastic fibers than tendons. Dense connective tissue also make up the lower layers of the skin (dermis), where it is arranged in sheets.[2]
Explain how thin a tissue must be in order to viewed through a microscrope
Embedding: Supports the tissue in wax or resin so that it can be cut into thin sections. Sectioning Produces very thin slices for mounting. Sections are cut with a microtome or an ulramicrotome to make them either a few micrometres (light microscopy) or nanometres (electron microscopy) thick.
List the basic four types (main groups) human tissues are divided into
Epithelial (covers), Connective tissue (supports), Nervous tissue (controls), and Muscle tissue (produces movement).
Explain the characteristics of fibrocartilage and where it is subsequently found
Explain the characteristics of fibrocartilage and where it is subsequently found compressible and resists tension well, fibrocartiale is found where strong support and the ability to withstand heavy pressure are required.
Explain what the prominent element/characterisitc of all dense connective tissue is. Due to this characteristic what other name can it also be referred to?
Fiber, and can also be called fibrous connective tissue.
Explain why fibrocartilage is describe as the perfect intermediate between hyaline cartilage and dense regular connective tissue
Fibrocartilage has characteristics intermediate between those of hyaline cartilage and dense connective tissue. Its presence indicates the need for resistance to compression and shear forces. It is found in the intervertebral disks, the symphysis pubis, the articular discs of the sternoclavicular and temperomandibular joints, the menisci of the knee joint and some places where ligamen
Explain what the most abundant cartilage in the human body is and where its found
Hyaline Cartilage. Lots of collagen fibers, but you can't see them on a stained slide. Used for firm support but pliable for cushioning. Most abundant type of cartilage in the body; found in the articular cartilage of the joints, tip of the nose, coastal cartilage of the ribs, the rings of the trachea, and the embryonic cells.
Explain the fiber difference between hyaline and elastic cartilage
Hyaline cartilage has widely dispersed fine collagen fibres (type II), which strengthen it. The collagen fibres are hard to see in sections. It has a perichondrium, and it is the weakest of the three types of cartilage. In elastic cartilage, the chondrocytes are found in a threadlike network of elastic fibres within the matrix. Elastic cartilage provides strength, and elasticity, and maintains the shape of certain structure such as the external ear. It has a perichondrium.
Explain where in the human body elastic cartilage could be found
It is found in the epiglottis (part of the larynx) and the pinnae (the external ear flaps of many mammals including humans). Elastin fibers turn dark purple/black with Verhoeff stain.
Describe "reticular lamina" and explain its function
Reticular lamina is a layer of extracellualr material containing a fine network of collagen protein fibers that "belong to" the underlying connective tissue. It's function is to reinforce the epithelial sheet, helps it resist stretching and tearing, and defines the epithelial boundary.
Describe how reticular tissue is similar to areolar tissue
Reticular tissue resembles areolar connective tissue, but only the fibers in its matrix are reticular fibers.
Explain the difference between simple and stratified endothelium
Simple epithelia consist of a single cell layer. Stratified epithelia is composed of two or more cell layers stacked on top of each other. Simple epithelia are found where absorption, secretion, and filtration occur and a thin epithelial barrier is desirable. Stratified epithelium is found where protection is important, such as the skin surface, and the lining of the mouth.
Explain what little cavities cartilage cells live in are called
The cartilage cells or chondrocytes are contained in cavities in the matrix, called cartilage lacunae; around these the matrix is arranged in concentric lines, as if it had been formed in successive portions around the cartilage cells. This constitutes the so-called capsule of the space. Each lacuna is generally occupied by a single cell, but during the division of the cells it may contain two, four, or eight cells. Lacunae are found between narrow sheets of calcified matrix that are known as lamellae (lah-MEL-ah).
List the three different fibers that occur in the matrix of some connective tissues
The intercellular matrix of loose connective tissue is composed of various fibers and ground substance. There are three types of fibers in the intercellular matrix of connective tissue: (1) collagen fibers, (2) reticular fibers, and (3) elastic fibers. The most prevalent protein in the body is collagen.
Explain what type of fibers are found in hyaline cartilage
The type of protein fiber embedded within the matrix of cartilage determines the cartilage type. In hyaline cartilage protein fibers are large and predominantly collagen. The optical density of these fibers is the same as the ground substance surrounding them and as a result, they are not visible within the extracellular matrix. Hyaline cartilage subsequently appears as a very uniform, glossy type tissue with evenly dispersed chondrocytes in lacunae. Typically, perichondreum is found around hyaline cartilage.
Describe what "tight junctions and desmosomes" are and explain their function and importance
Thight junctions and desmosomes are epithelial cells that fit closely together to form continuous sheet, bind adjacent cells together at many points. The tight junctions help keep proteins in the apical region of the plasma membrane from diffusing into the basal region, and thus help to maintain epithelial polarity
Describe a multicellular and unicellular gland and explain their differences
Unicellular- are mucous and goblet cells; inn epithelial linings of the intestinal and respiratorytracts amid columnar cells with other functions o The only important unicellular gland is thegoblet cell, the cuplike accumulation of mucin distends the top of the cell,making the cells look like a glass with a stem. • Multicellular- more complex; composed of a duct and a secretory unit; Classifiedaccording to: o Duct type (simple:unbranched duct or compound: branched duct) o Structure of their secretory units (tubular: tubelike , alveolar: small flasklike sacs, ortubuloalveolar: have both)
Explain what composes most of the adipose cell volume
a glistening oil droplet (almost pure triglyceride) occupies most of a fat cell's volume and displaces the nuclei...
Describe a secretion
a process by which substances are produced and discharged from a cell, gland, or organ for a particular function in the organism or for excretion.
Define the term "gland"
an organ in the human or animal body that secretes particular chemical substances for use in the body or for discharge into the surroundings.
Explain the characteristic that collagen fibers have due to the cross linked arrangement and describe where such fibers may be found
because they're cross linked, collagen fibers are extremely tough and provide high tensile strength(that is, the ability to be pulled apart) Stress test show that collagen fibers are stronger than steel fibers of the same size.
Explain how cartilage gets nutrients
by diffusion from blood vessels located in teh connective tissue membrane (perichondrium) surrounding it.
Explain what fibers are found in dense regular connective tissue and what can be said about the direction these fibers are arranged in and what characteristic does this arrangement provide
collagen fibers, running in the same direction, parallel to the direction of pull. The arrangement results in white, flexible structure with great resistance to tension ( pulling forces)
Describe the difference in the arrangement of collagen fibers in dense irregular connective tissue compare to dense regular connective tissue
dense irregular connective tissue is collagen fibers are much thicker and they are arranged irregularly; that is, they run in more than one plane/
List the three types of Dense Connective tissue
dense regular, dense irregular, and elastic...
Explain the derivation/meaning of stroma and describe its function
derivation/meaning of stroma is bed, mattress, or internal framework..can support many free blood cells (mostly lymphocytes) in lymph nodes, the spleen, and bone marrow.
Explain what is meant by the phrase "human body cells are specialized"
each individual body cells are speciliazed, with each type performing specific functions that help maintain homeostasis and benefit the body as a whole.
Describe the basic shape that all endothelia cells have in the transverse plane
epithelial sheet looks like a honeycomb.
What function does the elastic fibers provide and where is such a characteristic a benefit
few ligaments, such has those connecting adjacent vertebrae, arteries have stretchy sheets of elastic connective tissue in their walls
Explain, in general terms, what is meant by "epithelium covers and lines" and give some examples
forms outer layer of the skin, dips into and lines the open cavities of the urogenital, digestive, and respiratory systems; and covers the walls and organs of the ventral body cavity.
Describe where (which structures) dense regular and dense irregular would be found
found in the skin as the leathery dermis, and it forms fibrous joint capsules and the fibrous covering that surround some organs kidneys, bones, cartilages, muscles, and nerves
Explain what type of epithelium doesn't meet the previous definition in No.1 and discuss the function of this type of epithelium provides
glandular epithelium, which fashions the glands of the body
Explain what is meant by the statement that cartilage is avascular
lacks nerve fibers
Describe in what structures are dense regular connective tissues are typically
lymph nodes, bone marrow, and spleen
Explain what a microvilli is and what its function is
microvilli are fingerlike extensions of the plasma membrane. Its function is to absorb or secrete (export) substances. examples the lining of the intestine or kidneys tubules.
Explain what is meant by the phrase, "epithelium forms boundaries between environments"
nearly all substances received or given off by the body must pass through an epithelium.
Explain what functions epithelium can perform as an interfacing tissue
protection, absorption, filtration, excretion, and sensory reception
Explain how adipose tissue differs from areolar tissue
similiar to areolar tissue in structure and function, but its nutrient storing ability is much greater.
Explain the differences and similarities between single celled and complex multi-celled organisms regarding the way functions and activities to maintain life are carried out
single cells carries all activities to keep itself alive, and multi-celled organisms do not operate independently. Instead, they form tight cell communities that live and work together.
Explain what is meant by cartilage has qualities between bone and dense connective tissue
stands up to both tension and compression
Describe the basic function of areolar tissue
supporting and binding other tissues (the job of the fibers) holding body fluids (the ground substance's role) defending against infection (via the activity of white blood cells and macrophages) storing nutrients as fat cells
Explain how, due to the difference in fiber arrangement, the characteristics change and describe these differences
this type of tissue forms sheets in body of areas where tension is exerted from many different directions.
Explain what is meant by the term "tissue"
tissue is a group of cells that are similar in structure and perform a common or related function.
Name the wandering cells and describe their function
wandering cells move through the connective tissue and are components of the immune system EXAMPLE: different types of white blood cells wandering cells: mast cells secrete heparin and histamine wandering cells: plasma cells secrete antibodies wandering cells: free macrophages wander around wandering cells: other leukocytes white blood cells
Describe what functions simple epithelium is concerned with
with absorption, secretion, and filtration.
Explain how long we could live without eating if we didn't have any fat tissue
without the fat stores in our adipose tissue, we could not live for more than a few days without eating.
Differentiate between endocrine gland and exocrine glands
§ Endocrineglands - often called ductlessglands; secrete hormones that travel through lymph or blood to target organs;most are compact multicellular organs § Exocrineglands - More numerous than endocrine glands; Secrete products into ducts; Secretionsreleased onto body surfaces (skin) or into body cavities; Examples includemucous, sweat, oil, and salivary gland.
