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87 Cards in this Set

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General Considerations
Composed of closely aggregated polyhedral cells w/very little extracellular substance
Avascular, nourished by diffusion from adjacent CT, rich supply of sensory nerve endings
Cell Structure
Columnar, Cuboidal, Squamous w/nucleus formed corresponding to cell shape
Single (simple) or multiple (stratified) layers
Specialized Cells
Neuroepithelial cells have sensory function (i.e. taste buds)
Myoepithelial cells have contractile function (i.e. glands)
Intercellular Junctions - Structure
Structures on lateral membranes of cells that contribute to cohesion and communication between cells.
Present in most tissues, prominent in epithelia
Located from apex towards the base of the cell
Types of Intercellular Junctions
Tight
Adhering
Gap
Tight Junctions (Zonula Occludens)
A plasmalemmal fusion of adjacent cells. Prevents the flow of substances between cells
Adhering Junctions
Attachment of cytoskeletal elements of adjacent cells, through link proteins.
Provide firm adhesion, but space between cells is maintained
Parts of Adhering Junctions
Zonula Adherens
Desmosomes
Zonula Adherens
Encircles a cell and provides adhesion from one cell to its neighbor
Desmosomes
Macula Adherens - Disk-shaped structure at the surface of the adjacent cell
Gap Junctions
Communicating - Channels between adjacent cells. Allow metabolic and ionic coupling between cells (epithelial, cardiac muscle, smooth muscle)
Surface Specializations of Epithelial Tissue
Located on the free surface of some epithelial cells. Allow a specialized function
(microvilli, stereocilia, cilia)
Microvilli
Short, nonmotile, cytoplasmic projections or folds.
Composed of actin filaments.
May be none, few, or many per cell.
Increase surface area for absorption (i.e., small intestine)
Stereocilia
Long, branched, microvilli
Increase surface area for absorption (i.e., male reproductive system)
Cilia
Long, motile, cytoplasmic projections.
Composed of microtubules.
May be none, few, or many per cell
Transport substances (i.e., fallopian tubes, trachea)
Functions of Epithelial Tissue (5)
Protection
Absorption
Secretion
Sensation (neuroepithelium)
Contraction (myoepithelium)
How Epithelial Tissue is Classified
Number of cell layers
Shape of most superficial cells
Simple Squamous - Function
Absorption
Lines surfaces across which metabolites or gases must move rapidly
Simple Squamous - Distribution
Endothelium - inner lining of the blood vessels, Lymphatics, and Heart.
Mesothelium - Lining of the body cavities
Kidneys
Simple Cuboidal - Function
Protection, Secretion
Simple Cuboidal - Distribution
Covering of the ovary, thyroid.
Lines small ducts.
Kidney
Simple Columnar - Function
Protection, Absorption, Secretion
Simple Columnar - Distribution
Lining of the stomach, intestine, uterine cervix.
Lines ducts
Simple Pseudostratified - Function
Protection, Secretion
Simple Pseudostratified - Distribution
Lining of the upper respiratory tract, male reproductive tract
Stratified Squamous Keratinized - Function
Protection
Stratified Squamous Keratinized - Distribution
Epidermis of skin
Stratified Squamous non-keratinized - Function
Protection, Secretion
Stratified Squamous non-keratinized - Distribution
Mouth, esophagus, larynx, vagina, anal canal.
Stratified Cuboidal - Function
Protection, secretion
Stratified Transitional - Function
Protection, distensibility
Stratified Transitional - Distribution
Lining of the urinary tract
Stratified Columnar - Function
Protection
Stratified Columnar - Distribution
Conjunctiva
Lines large ducts
Keratin
Cytoskeletal intermediate filament that accumulates in epithelial cells during maturation.
Remains adherent to underlying layers of living cells
Definition of Gland
Individual cell, group of cells, or organ which is specialized to 'synthesize and release (secrete) a product used by other elements of the organism.
Definition of Secretion
Synthesis and release of cell products for further use outside the secreting cell(s)
Product Distribution Classification (Glandular Epithelia)
Exocrine, Endocrine
Type of Secretion Classification (Glandular Epithelia)
Exocrine (Mucous, Serous, Lipid)
Endocrine (Polypeptide, Steroid)
Structure Classification (Glandular Epithelia)
Unicellular (isolated cells)
Multicellular (clusters of cells)
Mode of Secretion Classification (Glandular Epithelia)
Merocrine (exocytosis), Apocrine (cell cytoplasm and secretory product), Holocrine (entire cell and secretory product), Diffusion
Exocrine Glands
Secretory products are released on to an epithelial surface either directly or via a duct or duct system
Polarized distribution of organelles
(Goblet Cells, Sheet Glands, Sweat Glands)
Endocrine Glands
Secretory products are released directly into the extracellular fluid and eventually into the blood or lymph (no duct system)
Do not display a polarized distribution
(Enteroendocrine Cells, Islets of Langerhans, Adrenal Glands)
Composition of Epidermis
Keratinized Stratified Squamous Epithelium
Organization of Epidermis - Superficial Layer
15-20 layers of flattened, non-nucleated, keratinized cells
Organization of Epidermis - Deep Layer
Single layer of columnar or cuboidal "keratinocyte" stem cells, which are mitotically active and produce keratin.
Cells differentiate as they move outwards, turnover from deep to superficial ranges from 25-50 days.
Epidermis Specializations (3 types)
Melanocytes, Merkel Cells, Langerhans Cells
Malanocytes
Produce pigment, melanin, which is essentially "injected" into keratinocytes
Merkel Cells
May serve as sensory mechanoreceptors or neuroendocrine cells
Langerhands Cells
Immune function
Dermis - Composition and Organization
Loose CT (Superficial Layer)
Dense Irregular CT (Deep Layer)
Dermis Specializations (3)
Dermal Papillae
Nonencapsulated Receptors
Encapsulated Receptors
Dermal Papillae
Projections of the dermis that interdigitate with evaginations of the epidermis, called epidermal ridges
Nonencapsulated Receptors
Sensitive to touch, pressure, pain, temperature
Extend into epidermis
Encapsulated Receptors
Function as mechanoreceptors, include Ruffini, Pacinian, Meissner, and Krause
Hypodermis
Subcutaneous Tissue, Superficial Fascia
Not part of skin
Loose CT w/variable number of adipose cells
Surface Specializations Derived From Epidermis
Hair, Nails, Glands
Sebaceous Glands
Produce and release sebum (complex lipid mixture)
Located in skin of most body regions except palms and soles
Sweat Glands
Produce and release sweat.
Eccrine - widely distributed
Apocrine - Distributed in axilla, areola, and circumanal regions
Regional Variations - Thick Skin
No hairs and sepaceous glands
Palms, Finger Tips, Soles
Regional Variations - Thin Skin
Contains hairs and sebaceous glands
Function of Skin
Protection, Sensation, Thermoregulation, Metabolic (vitamin D)
Basic Organization of the Circulatory System
Tunica Intima, Tunica Media, Tunica Adventitia
Tunica Intima
Layer closest to body
Commonly includes an endothelium, basement membrane, and subendothelial loose CT
Tunica Media
Middle Layer
Commonly includes smooth muscle and elastic lamellae
Tunica Adventitia
Layer furthest from blood
Commonly includes loose CT
Continuous w/CT of organ through which vessel runs
Composition of Circulatory System - Endothelium
Simple Squamous Epithelium
In tunica intima
Rests on basement membrane: carries a negative charge that repels circulating blood cells. Underlying basement membrane carries a positive charge that encourages platelet clotting
Composition of Circulatory System - Smooth Muscle
In all 3 tunics, most prominent in tunica media
Organized circularly - media
Organized longitudinally - intiima and adventitia
Composition of Circulatory System - Connective Tissue
In all 3 tunics, most prominent in tunica adventitia
Loose CT, but can be Dense irregular in larger vessels
Vessels contain concentric fenestrated (lamellae) or continuous (laminae) sheets of elastic fibers
Layers of the Heart
Endocardium
Myocardium
Epicardium
Endocardium
Inner layer composed of endothelium and basement membrane
Cardiac Valves
Folds of endocardium with central flat sheet of dense irregular CT
Myocardium
Middle layer composed of cardiac muscle tissue. Fibers insert on componenets of cardiac skeleton
Epicardium
Outer layer composed of simple squamous epithelium (mesothelium) supported by a thin later of dense irregular CT
Supporting Structure of the Heart
Cardiac Skeleton
Pericardium
Cardiac Skeleton
Composed of dense irregular CT: annuli fibrosi, fibrous trigones, septum membranaceum
Annuli Fibrosi
Rings surrounding each valve
Fibrous Trigones
Two triangular zones between annuli fibrosi
Septum Membranaceum
Superior portion of interventricular septum
Pericardium
Composed of inner visceral layer of simple squamous epithelium and outer layer of dense irregular CT
Covering Epithelium of Larynx -> Terminal Bronchiole
Ciliated pseudostratified columnar epithelium (Respiratory Epithelium)
Contains goblet cells that secrete mucous
Lamina Propria - Respiratory System
Loose CT underlying the covering epithelium
Includes elastic and reticular fibers, lymph tissue, smooth muscle, and/or glands (except at level of bronchiole)
Smooth muscle becomes more prominent towards the respiratory portion
Submucosa - Respiratory System
Middle layer of loose CT, contains glands (except at level of bronchiole)
Adventitia - Respiratory System
Outer layer. Commonly includes loose CT, but may be dense irregular CT in larger airways (i.e. trachea, bronchi)
Contains cartilaginous rings and plates (hyaline cartilage)
Interalveolar Septum
Consists of 2 layers of alveolar simple squamous epithelium, btw which lie capillaries, elastic and reticular fibers, and CT matrix.
Contains lung macrophages, called dust cells
Epithelial Lining Cells - Type I
97% of alveolar cells, squamous "lining" cells
Epithelial Lining Cells - Type II
Interspersed btw Type I cells, produce pulmonary surfactant which lowers the alveolar surface tension