Lab Exam 1 - Histology and Integumentary system Flashcards
Epithelial tissue
Lines and covers organs, creates boundaries between different environments, and forms glands
Epithelia functions
Filtration, absorption, protection, secretion, excretion, and sensory reception
Apical or free surface
Surface where cells are exposed to either external environment or to an internal passageway or cavity
These cells obtain nutrients by diffusion of substances from connective tissue underlying the epithelia
Basal lamina
Epithelium is attached to body via a basal lamina
Located between epithelium and its connective tissue layer
Functions as filter at base of epithelium
Simple epithelium
One layer
Main functions: Diffusion, absorption, filtration, and secretion
Microvilli or cilia on apical/free surface for increased surface area
Stratified epithelia
Composed of more than one layer
Found in areas exposed to abrasion and friction
Main function is protection
Stratified epithelia regenerate from basal cells and move out to replace older cells near apical border
Apical cells
Epithelial cells closest to external environment
Farthest from blood supply and thus atrophy and flatten (in stratified squamous)
Epithelial tissue characteristics
Regeneration: Easily regenerate; Good because many epithelia are exposed to friction or hostile substances
Polarity: Membranes always have one free surface (apical) and its significantly different from the basal surface; Apical surfaces commonly have microvilli and cilia
Cellularity and specialized contacts: Cells fit together to form membranes and are bound together
Supported by connective tissue: Cells are attached to and supported by a basement membrane
Avascularity: Lining epithelial tissues have no blood supply of their own, but instead depend on diffusion of nutrients from underlying connective tissue
Innervated: Supplied by nerve fibers
Basement membrane
An amorphous material secreted partly by epithelial cells and connective tissue cells that lie adjacent to each other with the reticular lamina deeper than the basal lamina
Helps epithelia resist tearing and stretching, reinforces structural integrity, and creates a boundary
Glandular epithelia
Very vascular
Makes up any gland in body
Function is directly related to its location
Simple squamous epithelium
Single layer of flattened cells with disc-shaped nuclei and sparse cytoplasm
Allows passage of materials by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosae
Located in kidney glomeruli, air sacs of lungs, lining of heart, blood vessels and lymphatic vessels, lining of ventral body cavity, ALVELOI
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Simple cuboidal epithelium
Single layer of cube-like cells with large, spherical central nuclei
Secretion and absorption
Located in the walls of ducts and secretory portions of small glands, KIDNEY TUBULES, ovary surface
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Simple columnar epithelium
Single layer of tall cells with round to oval nuclei; some cells bear cilia; layers may contain goblet cells (mucus-secreting unicellular glands)
Absorption; secretion of mucus, enzymes and other substances; ciliated type propels mucus by ciliary action
Nonciliated type lines most of DIGESTIVE TRACT, gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, UTERINE TUBES, and some regions of UTERUS
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Stratified squamous epithelium
Thick membrane composed of several layers; basal cells are cuboidal or columnar and metabolically active; surface are squamous; in keratinized type, surface cells are full of keratin and dead; basal cells are active in mitosis and produce the cells of the more superficial layers
Protects underlying tissues in areas subjected to abrasion
Nonkeratinized type forms the moist linings of esophagus, mouth, and vagina; keratinized variety forms the epidermis of the skin
Labelled: https://i.ytimg.com/vi/Yy2x3dWN7J4/maxresdefault.jpg
Keratinized: https://vmicro.iusm.iu.edu/hs_vm/images/epi9_kerat.jpg
Non-keratinized: https://study.com/cimages/videopreview/what-is-stratified-squamous-epithelium_01040301_139938.jpg
Pseudostratified ciliated columnar epithelium
Single layer of cells of differing heights; some not reaching the free surface; nuclei seen at different levels; may contain mucus-secreting cells and bear cilia
Secretion, particularly of mucus; propulsion of mucus by ciliary action
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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Transitional epithelium
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
Stretches readily and permits distension of certain hollow organs
Lines the URETERS, URINARY BLADDER, and part of the urethra
Unlabelled: https://images.fineartamerica.com/images/artworkimages/mediumlarge/2/3-urinary-bladder-transitional-epithelium-jose-calvo–science-photo-library.jpg
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Connective tissues
Provides body with structural support and a means of joining structural components to one another
Functions of connective tissue
Connects, protects, stores reserve energy, insulates body, and transports substances throughout the body
Cells within connective tissue
Cells in connective tissue are widely scattered throughout the tissue
These cells produce and secret protein fibers and a ground substance, that together form the extracellular matrix
Suspended in the ground substance are collagen fibers, elastic fibers, and reticular fibers
Collagen fibers
The strongest fiber
Made up of the protein collagen
Made up of many cross-linked collagen fibrils which is what gives the fibers their strength
Elastic fibers
Largely made of elastin, a protein which forms a branching network in the extracellular matrix to provide stretch and recoil
Connective tissue will stretch to the limits of collagen fibers and then recoil back due to elastic fibers
Reticular fibers
Short, fine fibers made also of collagen but with a different chemistry and form than that of the collagen fibers
Reticular fibers form fuzzy nets that have more give or play
Connective tissue proper
Loose and dense connective tissue
A thick liquid matrix and a variety of cell types
Fibroblasts
Stationary cells that secrete proteins that join other molecules in the matrix to form fibers
Mast cells
Detect foreign microorganisms and initiate immune responses against them
Loose connective tissue
Areolar, adipose, and reticular
Dense connective tissue
Made up of two types of fibers: protein fibers assembled it thick bundles of collagen and elastic fibers of widely scattered cells
Dense regular
Type of dense connective tissue
Proteins fibers in the matrix are arranged in parallel bands
Dense irregular
Type of dense connective tissue
Fibers are interwoven
Has fibers that run in many directions and is found where tension is exerted from many different directions
Fluid connective tissue
Two types: Blood and lymph
Blood contains red blood cells and white blood cells
Leukocytes mediate immune responses and tissue response to injury
Supporting connective tissue
Two types: Bone and cartilage
Contain a strong matrix of fibers capable of supporting body weight and stress
Three types of cartilage
Hyaline, elastic, and fibrocartilage
Areolar tissue
Loose connective tissue
Gel-like matrix with all three fiber types; cells: fibroblasts, macrophages, mast cells, and some white cells
Wraps and cushions organs; its macrophages phagocytize bacteria; plays important role in inflammation; holds and conveys tissue fluid
Widely distributed under the skin
Unlabelled: https://images.fineartamerica.com/images-medium-large-5/11-areolar-connective-tissue-lm-science-stock-photography.jpg
Labelled: https://diagramweb.net/img/areolar-connective-tissue-diagram.png
Adipose tissue
Loose connective tissue
Displacement of nucleus and cytoplasm due to storage of lipids
Matrix as in areolar, but very sparse; closely packed adipocytes (fat cells) have nucleus pushed to the side by large fat droplet
Provides reserve food fuel; insulates against heat loss; supports and protects organs
Under skin in subcutaneous tissue; around kidneys and eyeballs; within abdomen; in breast
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Reticular tissue
Network of reticular fibers in a typical loose ground substance; reticular cells lie on the network
Fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages
Lymphoid organs (lymph nodes, bone marrow, and spleen)
Unlabelled: https://cdn.lecturio.com/assets/White-adipose-tissue.jpg
Labelled: https://www.onlinebiologynotes.com/wp-content/uploads/2018/02/reticular-tissue.jpg
Dense regular connective tissue
Primarily parallel collagen fibers; a few elastic fibers; major cell type is fibroblast
Attaches muscles to bones or to muscles; attaches bone to bone; withstands great tensile stress when pulling force is applied in one direction
Located in tendons, most ligaments, aponeuroses
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Fascia
Flat layers of dense regular connective tissue
Protects and isolates muscles from surrounding structures and allows muscle movement
Dense regular elastic tissue
Dense regular elastic tissue containing a high proportion of elastic fibers
Allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs through respiration
Located within walls of large arteries; within certain ligaments associated with vertebral column; within the walls of bronchial tubes
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Blood
Composed mostly of formed elements that are suspended in a liquid ground substance called plasma
Formed elements: red blood cells, white blood cells, platelets
Red and white blood cells in a fluid matrix
Transport of respiratory gases, nutrients, wastes, and other substances
Contained within blood vessels
Unlabelled: https://med.libretexts.org/@api/deki/files/38248/Blood_Connective_Tissue_%2540400x.jpeg?revision=1&size=bestfit&width=676&height=305
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Hyaline cartilage
Most common cartilage in the body
Has an apparent lack of fibers in the matrix; they are not visible
Amorphous but firm matrix; collagen fibers form an imperceptible network; chondroblasts produce the matrix and when mature lie in lacunae
Supports and reinforces; has resilient cushioning properties; resists compressive stress
Forms most of embryonic skeleton; covers the ends of long bones in joint cavities; forms costal cartilages of the ribs; cartilages of the nose, trachea, and larynx
Unlabelled: https://medcell.org/histology/connective_tissue_lab/images/hyaline_cartilage.jpg
Labelled: https://o.quizlet.com/KscJD7MI75FurOdFqObaCw.jpg
Elastic cartilage
Similar to hyaline cartilage, but more elastic fibers in matrix
Maintains the shape of a structure while allowing great flexibility
Supports the external ear; epiglottis
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Fibrocartilage
Matrix similar to but less firm than that in hyaline cartilage; thick collagen fibers predominate
Tensile strength with the ability to absorb compressive shock
Intervertebral discs, pubis symphysis, discs of knee joint
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Skeletal muscle tissue
Composed of long cells called muscle fibers
Long, cylindrical, multinucleate cells; obvious striations
Voluntary movement; locomotion; manipulation in the environment; facial expression
In skeletal muscles attached to bones or occasionally to skin
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Labelled: https://embryology.med.unsw.edu.au/embryology/images/6/6e/Skeletal_muscle_histology_012.jpg
Cardiac muscle tissue
Branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs); contains striations
As it contracts, it propels blood into circulation; involuntary control
Located within the walls of the heart
Unlabelled: https://histology.siu.edu/ssb/images/NM018b.jpg
Labelled: https://embryology.med.unsw.edu.au/embryology/images/e/ef/Heart_histology_002.jpg
Smooth muscle tissue
Spindle-shaped cells with central nuclei; no striations; cells arranged closely to form sheets
Propels substances or objects along internal passageways; involuntary control
Located mostly in walls of hollow organs
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Nervous tissue
Made up of cells called neurons and glial cells
Neurons are branching cells; cell processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are the non-irritable supporting cells
Transmit electrical signals from sensory receptors and to effectors (muscles and glands)
Located in brain, spinal cord, and nerves
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Labelled: https://histology.siu.edu/ssb/images/motoneur.jpg
Osteon cell
Unlabelled: https://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Bone_connective_tissue.jpg/220px-Bone_connective_tissue.jpg
Labelled: https://upload.wikimedia.org/wikipedia/commons/thumb/9/98/Transverse_section_of_bone_en.svg/1200px-Transverse_section_of_bone_en.svg.png
https://pressbooks.pub/app/uploads/sites/7863/2024/01/Slide1-e1704667164873-1024x593.jpg
Integumentary system
Comprises of skin and its derivatives (sweat and oil glands, hair, and nails)
Unlabelled: https://www.researchgate.net/publication/309480351/figure/fig1/AS:421942487457792@1477610336148/Microscopic-image-of-real-human-skin-presenting-the-two-defined-layers-Epidermis-and.png
Labelled: https://cdn.ps.emap.com/wp-content/uploads/sites/3/2019/11/Fig-2-Layers-of-the-skin-1024x758.jpg
https://upload.wikimedia.org/wikipedia/commons/8/84/Epidermis-delimited.JPG
Skin
Skin is largest organ of body
Two main tissue layers: superficial and avascular epidermis and the deep and vascularized dermis layer
Integumentary system functions
Regulate body temperature, house sensory receptors, ensure water homeostasis, protect the body from environment, and manufacture vitamin D3
Epidermis
Consists of keratinized stratified squamous epithelium organized into layers called strata
Most cells in epidermis are keratinocytes (produce the protein keratin)
Keratinocytes are produced by basal layer of the epidermis and migrate out
As they move, they fill with keratin and gradually lose all other function until they fall off body
Five layers of epidermis: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, stratum basale (Come Lets Get Sun Burnt)
Dermis
Layer of irregularly arranged flexible, but strong, connective tissue that supports and nourishes the epidermis
Contains rich supply of nerve fibers, blood vessels, and lymphatic vessels
Divided into two layers: Papillary and reticular
Papillary layer
Consists of areolar tissue that contains collagen and elastic fibers Folds in the papillary layer, called dermal papillae, form large mounds in thick skin called dermal ridges that make-up fingerprints
Layer also houses phagocytes that protect us from bacteria
Reticular layer
Below the papillary layer
Contains thick collagen fibers in dense, irregular connective tissue with pockets of adipose cells
Hair follicles and glands originate from this follicle
Terminal hair
Thich, coarse, heavy, dark hairs on scalp, eyebrows, and eyelashes
Vellus hair
Lightly pigmented and distributed over much of the skin as fine “peach fuzz”
Pale and found all over bodies of children and adults
Intermediate hair
Hair on arms and legs
Sebaceous glands
Oil glands
Flank hair follicle; Where sebum (oil) is secreted
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Sebum
Functions as lubricant for hair root (below surface of skin)
Secreted onto outer surface of stratum corneum, where it serves as an antibacterial function and as a lubricant for surrounding skin
Exocrine glands
Secrete their substances onto a body surface or into a body cavity and do not release hormones into circulation
Unicellular exocrine glands release secretions by exocytosis directly onto epithelial surface
Multicellular glands release secretions through a duct on its way to the surface
Produces substances such as saliva, oil, sweat, mucus, bile, and digestive enzymes from the pancreas
