Chapter 4 - Tissue Flashcards
1
Q
Tissue
A
Groups of cells that are similar in structure and perform a similar or related function
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Q
Epithelial Tissue
A
sheet of cells that covers a body surface; or lines a body cavity; found in the body:
- Covering and lining
- As glandular epithelial (makes up glands). Typically found in GI gastinual intestine tract (mouth all the way to the anus, inside the thorax, in the abdomen, and on our skin)
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Q
Epithelial General Functions
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- Protection undying tissue from mechanical injury, harmful chemicals, pathogens, and from excessive water loss.
- Sensory stimuli are detected by specialized epithelial cells, sensory nerve endings is found in the skin, eyes, ears, nose and tongue.
- Secretions specific chemical substances (enzymes, hormones, and lubricated fluids).
- Absorption of nutrients from the digestion of food
- Excretion in the kidneys excretes waste products from the body and reabsorbs needed materials from the urine. Sweat is also excreted from the sweat glands
- Filtration found in kidneys
- Diffusion promotes gasses, liquids, and nutrients it can do this because how thin it is (found in lungs)
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Q
Epithelial General Characteristics
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- Arrangement of cells – composed of closely packet cells and their continuous sheets which are held together by tight junctions and desmosomes (macula adherins) which are specialized for cell to cell adhesions.
- Polarity – surfaces
- Connective tissue support – is support that is given to epithelium physically and it provides nutrients
- Vascularity – blood supply. Epithelium tissue is A vascular (doesn’t have blood supply but has nerve intervasion)
- Regeneration – high rate regeneration (rapid repair) it will regenerate as long as it receives proper nutrients
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Q
Apical Surfaces
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Upper or free surface of epithelial tissue; can be smooth and slick but most will have microvilli or cilia
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Q
Microvilli
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Fnger like extensions or the plasma membrane they increase the surface area in epithelial that absorb and secrets substances. It is often so dense that the cell apexes have a fuzzy appearance (brush boarder)
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Q
Cilia
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Found in specific spaces (lining of trachea), they are tiny hair like projects that propel substances along their free surfaces.
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Q
Basal Surface
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Lower attached surface of epithelial tissue
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Q
Basal Lamina
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None cellular, it’s a thin cellular sheet of glycol-proteins + fine collagen fibers. It acts as a selective filter that determines which molecules can cross from the connective
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Q
Reticular Lamina
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A layer of extra cellular material which contains collagen protein
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Q
Basement Membrane
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Formed by the two lamina (basal and reticular lamina)
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Q
Classification - Number of Cell Layers
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A. Simple epithelia – single cell layer and is typically found where absorption, secretion, and filtration occur.
B. Stratified epithelia – composed of 2 or more cells layers stacked one on top of the other and is common in high abrasion areas where protection is important (skin surface and inside the mouth)
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Q
Classification - Cell Shape
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A. Squamous cells – flattened and scale like
B. Cuboidal cells – box like they are as tall as they are wide
C. Columnar cells – tall and column shaped
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Q
Simple Squamous Epithelia
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- Description – single layer of flatten cells with disc shaped central nuclei, this is the simplest of the epithelia
- Functions – allows passage of materials by diffusion and filtration and also secreted lubrication
- Locations – where protection is NOT important, kidney glomeruli, air sacs of the lungs, lining of the heart, lining of blood vessels, lining of lymphatic vessels, and lining of ventral body cavity
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Q
Endothelium
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Specialized, simple squamous epithelium found in the lymphatic vessels and in all hollow organs of the cardiovascular systems (blood vessels and the heart) capillaries consists exclusively of endothelium and its thinness encourages the efficient exchange of nutrients and wastes between the bloodstream and surrounding tissue cells.
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Q
Mesothelium
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The epithelium found in serous membranes lining the ventral body cavity and covering its organs
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Q
Simple Cuboidal Epithelium
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- Description – single layer of cube like cells with large sphere central nuclei
- Functions – secretion and absorption
- Locations – in the kidney tubules, ducts and secretory portions of small glands and surface of the ovaries
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Q
Simple Columnar Epithelium
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- Description – single layer of tall cells with round to oval nuclei some contain cilia and some layers may contain mucus secreting unicellular (goblet cells)
- Functions – absorption and secretion of mucus, enzymes and other substances, cilia types are going to propel mucus
a. Goblet cells – mucosa pockets - Locations –lines most of digestive tract, gallbladder, and excretory ducts of some glands. Ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus
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Q
Pseudostratified Columnar Epithelium
A
- Description – single layer of cells of differing heights, some not reaching, the free surface; nuclei seen at different levels; may contain goblet cells and bear cilia
- Functions – secretion, particularly of mucus; propulsion of mucus by ciliary action
- Locations – nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract
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Q
Stratified Squamous Epithelium
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- Description – thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers
- Functions – protects underlying tissues in areas subjected to abrasion
- Locations – nonkeratinized type forms the moist lining of the esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin, a dry membrane
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Q
Stratified Cuboidal Epithelium
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Rare in the body, mostly found in the ducts of some of the larger glands (sweat glands, mammary glands)
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Q
Stratified Columnar Epithelium
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Limited distribution in the body; small amounts are found in the pharynx, the male urethra, and lining some glandular ducts; also occurs at transition areas or junctions between two other types of epithelia
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Q
Transitional Epithelium
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- Description – resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamous like, depending on degree of organ stretch
- Functions – stretches readily and permits distension (swelling) of urinary organ by contained urine
- Locations – lines the ureters, bladder, and part of the urethra
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Q
Glandular Epithelia
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a. Glands – consists of one or more cells that make and secrete a particular product
b. General classification – endocrine (internally secreting) or exocrine (externally secreting) depending on where they release their product, and as unicellular or multicellular based on the relative cell number making up the glands
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Location of Secretion for Glandular Epithelia
A. Endocrine – ductless glands – they produces hormones that travel from lymph or blood to target organs
B. Exocrine – numerous, and many of their products are familiar, all exocrine glands secrete their products onto body surface (skin) or into body cavities – the unicellular glands directly and the multicellular glands via an epithelium walled duct that transports the secretion to the epithelial surface.
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Number of Cells
A. Unicellular – sprinkled in the epithelial linings of the intestinal and reparatory tracts in between columnar cells with other functions
B. Multicellular – have two basic parts: an epithelium – derived duct and a secretory unit consisting
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Goblet Cells
a. Description – glandular simple columnar cells
b. Functions – secrete mucin which dissolves in water to form mucus
c. Locations – small intestine, colon, repertory tract
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Multicellular Exocrine Glands
1. Components
a. Duct
i. Simple – unbranched duct
ii. Compound – have branched ducts
b. Secretory unit
i. Tubular – cells form tubes
ii. Alveolar – form small, flask like sacs
iii. Tubuloalveolar – if they have both types of secretory units 2. Examples
3. Functions – duct - expel secretions to the surface; secretory – produce secretions
4. Merocrine – secrete their products through Exocytosis (pancreases, most sweat glands, and salivary glands which belong to this class) or holocrine – accumulate their products within them until they rupture
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Connective Tissue
A. General locations – everywhere in the body and in about every organ system; quantity varies by organ (skin has more than brain)
B. General functions – binding and support, protection, connection, insulation and transportation
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Connective Tissue General Characteristics
1. Mesenchyme
2. Vascularity
3. Extra cellular matrix
4. Cells
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Extra Cellular Matrix
most abundant and widely distributed primary tissue; they have some common characteristics that set them apart from other primary tissues. 1. Common origin – mesekine (embryonic tissue).
2. Vascularity – very vascular, poorly vascular (dense tissue), or a vascular (cartilage)
3. Extra cellular matrix – nonliving and it separates cells
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Connective Tissue Extra Cellular Matrix Fibers
1. Collagen fibers – rope like, made of collagen, main and largest fibers; abundant, strongest, and high tensile strength.
2. Elastic fibers – made of protein elastin (rubber like protein), can stretch and bend, they are long, thin and found where greater elasticity is needed (skin, lungs and blood vessels)
3. Reticular fibers – collaginious protein fibers; they are short, fine and highly branched fibers and found in areas such as basement membrane.
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Extra Cellular Ground Substance
Unstructured material that fills the space between the cells, and contains fibers; composed of interstitial fluid, cell adhesion protein and protoglycons
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Connective Tissue Cells
a. Major cell types
i. Immature form – undifferentiated cells and they’re indicated by the suffix blast; actively mitotic cells. fiberblast, cartilage- condroblast, bone – ostioblast)
ii. Mature form – maintain health and they end in
b. Additional cell types (fat cells, neutrophil (white blood cells), mast cells, and macrophage)
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Connective Tissue Classification
1. Connective tissue proper - fat and fibrous tissue.
2. Cartilage
3. Bone
4. Blood
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Loose Connective Tissue: Areolar Connective Tissue
A. Fibers – all 3 types of fibers, collagen, elastic, and reticular fibers
B. Cells – fibroblast, macrophages, mast cells, white blood cells, and fat cells
C. Description – loose fiber arrangement, gel like matrix with three fiber types
D. Functions – wraps and cushions organs its macrophages phagocytize bacteria (fights of bacteria), plays important role in inflammation, hold and conveys tissue fluid
E. Locations – widely distributed under epithelia of body (forms lamina propria of mucous membrane; packages organs; surrounds capillaries)
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Loose Connective Tissue: Adipose Tissue
A. Fibers – all 3 (collagen, elastic and reticular)
B. Cells – adipose cites (fat cells), nuclei is pushed out
C. Description – very vascular and nucleus is pushed to the side in each adipose cite
D. Functions – storage or energy and nutrients, provides reserve food fuel; insulates against heat loss; supports and protects organs
E. Locations – under skin in the hypodermis, around kidneys and eyeballs; within abdomen and breast
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Loose Connective Tissue: Reticular Connective Tissue
A. Fibers – reticular fibers
B. Cells – reticular cells and white blood cells
C. Description – network of reticular fibers in a typical loose ground substance; reticular cells lie on the network
D. Functions – fibers form a soft internal skeleton (stroma) that supports other cell types (white blood cells, mast cells, and macrophages)
E. Locations – lymphoid organs (lymph nodes, bone marrow, and spleen)
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Dense Connective Tissue: Dense Regular Connective Tissue
A. Fibers – collagen and few elastic fibers
B. Cells – fibroblast
C. Description – poorly vascularized, and is resistant to tension in a single direction; primarily parallel collagen fibers; a few elastic fibers; major cells type is the fibroblast
D. Functions – attaches muscles to bones or to muscles or bones to bones; with stand great tensile stress in one direction
E. Locations – tendons (muscle to bone), most ligaments (bone to bone), and aponeuroses (muscle to muscle)
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Dense Connective Tissue: Elastic Connective Tissue
Similar to dense regular but has more elastic fibers
A. Function – it allows recoil of tissue
B. Location – in arteries, large artery, bronchial tubes, and in ligament of the vertebral column
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Dense Connective Tissue: Dense Irregular Connective Tissue
A. Fibers – collagen and some elastic
B. Cells – fibroblasts
C. Description – primarily irregularly arrange collagen and elastic fibers
D. Functions – able to withstand tension exerted in many directions; provides structural strength
E. Locations – capsules of joints and organs, in the dermis of the skin, and the submucosa of digestive tract
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Cartilage
A. Fibers – collagen and elastic fibers
B. Cells – condroblast and condrocytes located in the lacunae
C. Description – 80% water, lacks nerve fibers and avacular; quality of dense connective tissue and bone
D. Functions – supports and reinforces; has resilient cushioning properties; resists compressive; withstands tension and compression
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Hyaline Cartilage
A. Fibers – collagen fibers
B. Cells – condroblast and condrocytes
C. Description – amorphous matrix (unable to distinguish fibers)
D. Functions – supports, reinforces, has resilient cushioning properties, and it resists compressive stress
E. Locations – forms most of the embryonic skeleton; covers the ends of long bones in joints cavities; forms costal cartilage of the ribs; cartilages respiratory systems(of the nose, trachea, and larynx)
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Elastic Cartilage
A. Fibers - collagen fibers and elastic fibers in matrix
B. Function - maintain the shape of a structure while allowing great flexibility
C. Location - Support the pinna and epiglottis
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Fibrocartilage
A. Fibers - collage fibers
B. Description - thick collagen fibers predominate
C. Function - tensile strength with the ability to absorb compressive shock
D. Locations - Intervertebral discs, pubis symphysis, disc of knee joint
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Bone: Osseous Tissue
A. Fibers - collagen fibers
B. Description - Hard, calcified matrix; osteocytes lie in lacunae. Very well Vascularized
C. Function - Bone support and protects (by enclosing), provides levers for the muscles to act on, stores calcium and other minerals and fat, marrow inside bones is the site for blood cell formation.
D. Location - bones
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Blood
A. Description - Red and white blood cells in a fluid matrix (plasma)
B. Function - transport of respiratory gases, nutrients, wastes and other substances
C. Location - contained within blood vessels
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Nervous Tissue
A. Description - Neurons are branching cells, cell processes that may be quite long extend from the nucleus containing cell body, also contributing to nervous tissue are nonirritable supporting cells
B. Function - Transmit electrical signals from sensory receptors and to effectors (muscles and glands) which control their activity
C. Location - brain, spinal cord and nerves
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Skeletal Muscles
A. Description - long, cylindrical, multinucleate cells, striated
B. Function - voluntary movement, locomotion, manipulation of the environment, facial expressions, voluntary control
C. Location - in skeletal muscles attached to bones or occasionally to skin
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Cardiac Muscles
A. Description - branching, striated, generally uninucleate cells that interdigitate at specialized junction
B. Function - as it contracts it propels blood into the circulation; involuntary control
C. Location - walls of heart
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Smooth Muscles
A. Description - spindle-shaped cells with central nuclei, no striations, cells arranged closely to form sheets
B. Function - propels substances or objects (food) along internal passageways; involuntary control
C. Location - Mostly in the walls of hollow organs
