- What is a definition for tissue? What is the study of tissues called?
Tissues - Collection of specialized cells and cell products that carry out a limited number of functions
Histology
- Name the 4 categories of tissues in the human body and briefly describe each type of tissue.
- Epithelial tissue - Covers exposed surfaces, lines internal passageways and chambers, and forms glands
- Connective tissue - Fills internal spaces, provides structural support for other tissues, transports materials within the body, and stores energy
- Muscle tissue - Specialized for contraction and includes the skeletal muscles of the body, the muscles of the heart, and the muscular walls of hollow organs
- Nervous tissue - Carries information from one part of the body to another in the form of electrical impulses.
- Distinguish between epithelia and glands.
Epithelia - layers of cells that cover external or line internal surfaces
Glands - Are structures that produce fluid secretions
- List five important characteristics of epithelial tissue.
- Polarity
- Cellularity
- Attachment
- Avascularity
- Regeneration
- Identify and describe the four essential functions of epithelial tissue.
- Provide physical protection - Protect exposed and internal surfaces from abrasion, dehydration, and destruction by chemical or biological agents
- Control permeability - Any substance that enters or leaves the body must cross an epithelium
- Provide sensation - Most epithelial are extremely sensitive to stimulation, because they have large sensory nerve supply
- Produce Specialized Secretion - Epithelial cells that produce secretions are called gland cells. Individual gland cells are usually scattered among other types in an epithelium.
- What is the probable function of an epithelial surface whose cells bear many microvilli? Where in the body can these specialized cells be found?
Increase surface volume
Where absorption and secretion take place
- What is the probable function of an epithelial surface whose cells bear cilia? Where in the body can these specialized cells be found?
Movement of substances over the epithelial surface
Respiratory tract
- Identify and describe the three most common types of epithelial cell junctions. Provide an example of a location in the human body where each of these junctions is utilized.
Gap junction - Two cells held together by two embbeded interlocking transmembrane proteins connection.
- Epithelial cells, cilia
Tight junctions - The lipid portions of the two plasma membranes are tightly bound together by interlocking membrane proteins
- Apical regions of epithelial cells
Desmosomes- CAMs and proteoglycans link the opposing plasma membranes
- Epithelium
- Epithelial cells often have a hard life!! What type of cell is necessary to maintain the structure of epithelia?
Stem Cells
- Epithelia can easily be sorted into categories based on what two criteria?
Epithelia and glands
- What three basic shapes do epithelia possess?
Squamous
Cuboidal
Columnar
- Once you have determined the shape of the superficial cells, then you will need to look at the number of cell layers. You have two options, what are they?
Simple
Stratified
- Name the functions and locations of simple squamous epithelium.
Protected regions where absorption or diffusion takes place
Alveoli
Lining of the thoracic and abdominopelvic body cavities
Lining of the heart and blood vessels
- Name the functions and locations of stratified squamous epithelium.
Located where mechanical stresses are severe.
Surface of the skin
Lining of the mouth, esophagus, and anus
- What is keratin? What function does it perform? Provide examples of keratinized and nonkeratinized stratified squamous epithelia.
- Protein
- Tough and water resistant - are keratinized
- Nonkeratinized resists abrasion, but will dry out and deteriorate unless kept moist
- Name the functions and locations of simple cuboidal epithelium.
- Limited protection, secretion, and absorption
2. Glands, ducts, kidneys, thyriod
- Name the functions and locations of stratified cuboidal epithelium.
- Protection, absorption, and secretion
2. Lining of some ducts
- Name the function and locations of transitional epithelium.
Permits repeated stretching without damage
Urinary bladder, renal pelvis, ureters
- Name the functions and locations of simple columnar epithelium.
Protection, secretion, and absorption
Lining of the stomach, intestine, gall bladder, uterine tubes, and collecting ducts of kidneys
- Name the functions and locations of pseudostratified columnar epithelium. What structures typically line the apical surface of pseudostratified columnar epithelia?
Protection, secretion, move mucus with cilia
Nasal cavity, trachea, and bronchi, portions of the male reproductive tract
- Compare and contrast endocrine and exocrine glands.
Endocrine - Release secretions into the blood
Exocrine - Release secretions into an epithelia surface or a duct
- What are the secretions from endocrine glands called?
Hormones
- Name several locations where endocrine glands are located in the body.
Thyroid
Thymus
Pituitary glands
Exocrine glands have several different modes of secretion. Distinguish between the modes of secretion and provide examples of each…
Merocrine secretion
Secretory vesicles through exocytosis mucous secretions of the salivary glands.
Exocrine glands have several different modes of secretion. Distinguish between the modes of secretion and provide examples of each…
Apocrine secretion
Loss of cytoplasm as well as the secretory product
Exocrine glands have several different modes of secretion. Distinguish between the modes of secretion and provide examples of each…
Holocrine secretion
Destroys the gland cell. Sebaceous glands with hair follicles
- What are the three basic components of connective tissue? What is matrix?
- Specialized cells
- Extracellular protein fibers
- Fluid - ground substance matrix (surrounds the cell) - extracellular fibers and ground substance
Fibroblast
Production of the connective tissue fibers
Fibrocyte
Maintenance of the connective tissue fibers
Adipocyte
Energy storage
Mesenchymal cells
Stem cells which can differentiate into fibroblasts
Mast cells
Release histamine and heparin
Macrophages
Phagocytes that engulf damaged cells or pathogens
Lymphocytes
Defense of the body; some produce antibodies
Melanocytes
Produce a brown pigment called melanin
- Many allergy sufferers take antihistamines to relieve their allergy symptoms. Which cells produce the molecule that this medication blocks?
Mast cells
- List the three types of connective tissue fibers and their primary function.
- Collagen - tendons and ligaments
- Reticular - resists force from many directions
- Elastic - after streaching, return to original length
- List the 3 types of loose connective tissue in adults, where they are normally found in the body, and their primary function.
Areolar
- Dermis of the skin, digestive, respiratory, urinary, between muscles, around joints, blood vessels, and nerves. - Cushions, provides support, phagocytics cells for defense
Adipose
- Under the skin of the sides, buttocks, and breast. Behind the eyes and around the kidneys
- Provide padding, absorbs shock, insulator, and filler
Reticular
- Liver, kidneys, and spleen
- Supports the functional cells of the organ, forms a 3D stroma
- Distinguish between dense regular and dense irregular connective tissue. Provide examples of each type of connective tissue in the human body.
Regular - collagen fibers are parallel to each other, tightly packed (tendons)
Irregular - collagen is interwoven in no consistent (dermis)
- _____________________ connect muscle to bone. __________________ connect bone to bone.
Tendons
Ligaments
- What cell stimulates the inflammatory process by releasing histamine, heparin, and prostaglandins?
Mast cells
- List the four signs of inflammation
Redness, swelling, heat, and pain
- Define necrosis.
Tissue destruction after cells have been damaged or killed
- What is pus? What is an abscess?
Pus - Collection of debris, fluid, dead / dying cells
Abscess - Accumulation of pus in an enclosed tissue space
- Briefly describe which tissues regenerate well and those which regenerate poorly.
Well - Epithelia, connective tissues, smooth muscle, skin
Poorly - Skeletal and cardiac muscles and nervous tissues
- Identify some age-related factors that affect tissue repair and structure.
Maintenance activities decrease
Rate of energy decreases
Hormonal alterations
- What would account for the observed increase in cancer rates with age?
Longer exposure to chemical and environmental factors