Flashcards in Chapter 4 Part 1 Deck (70):
Work together in functionally related groups called tissues
Group of closely associated cells that perform related functions and are similar in structure
What are the components of tissues?
Cells and extracellular matrix
What makes up the extracellular matrix?
Ground substance and fibers
Describe collagenous fibers
Keeps the tissue from tearing, produces tensile, flexible strength
Describe Reticular fibers
Forms a storm or framework of an organ
Describe elastic fibers
Stretch and recoil to normal shape
Describe epithelial tissue
Covers a body surface or lines a body cavity, forms most glands
How are tissues distinguished?
By the type of cells, distribution of cells, components and distribution/amount of extracellular matrix
Name the 6 functions of epithelial cells
Protection, secretion, absorption, diffusion, filtration, sensory reception
What are 6 special characteristics of epithelia?
Cellularity, specialized contacts, polarity, support by connective tissue, avascular but innervated, regeneration
Allows sensory receptors to send messages to the brain
Where does the epithelia receive nutrients?
From underlying connective tissues
What binds epithelial cells together?
Adhesion proteins, contours of adjacent membranes, and cell junctions
Describe tight junctions
Found at apical region of epithelial tissues, close off intercellular space and prevents fluids from leaking between cells
Describe adhesive belt junctions
Anchoring junction that holds the cell together and supports tight junctions
Describe transmembrane linker proteins
Attach to actin microfilaments of the cytoskeleton and bind adjacent cells, around apical lateral boarders or tissues
Main junctions for binding cells together, scattered along abutting sides of adjacent cells. Filaments extend across cytoplasm to anchor at desmosomes on opposite sides
Where are desmosome common?
Cardiac muscle and epithelial tissues, wherever there is a lot of friction
Describe gap junctions
A passageway between two cells connected by hollow cylinders of protein that let small molecules move
Where are gap junctions common?
Embryonic tissue, cardiac muscle, smooth muscle, connective tissue
Describe a connexon
Allows communication and transportation, formed by proteins, found on a gap junction
Describe the basal lamina
Located at the boarder of epithelium and connective tissue, consists of proteins secreted by epithelial cells
What are the components of the basement membrane?
Reticular lamina and basal lamina
What is the function of the Basal Lamina?
Acts as a selective filter and a scaffolding allowing migration of regenerated epithelial tissue cells
What are two features of the apical surface?
Cilia and microvilli
Fingerlike extensions of plasma membrane with a core of actin filaments that stiffen it. Maximizes surface area so molecules can enter or leave
Where are microvilli found?
Kidney tubules, small intestine, mucus secreting epithelium
Whiplike, highly motile extensions of apical surface membranes that generate movement. Contain a core of microtubules held together by cross linking and radial proteins
Motor protein used to grip doublets and propel movement in cilia
Single layer of cells attached to basement membrane
Multiple layers of cells, basal layer is attached to basement membrane
Cells wider than tall, nucleus sits higher than cell
Cells are as wide as they are tall, circular and centered nucleus
Cells are taller than they are wide, nucleus is towards the bottom
How are cells named?
Based on the apical surface
Function of simple squamous epithelial
Diffusion and filtration
Function of stratified squamous epithelial
Function of simple cuboidal/columnar
secretion and absorption; ciliated types propel mucus or reproductive cells
Function of stratified cuboidal/columnar
Protection; very rare
Function of transitional epithelial
Protection; stretching to accommodate dissension of urinary structures
Where are simple squamous epithelium found?
Kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, lymphatic vessels, serosae, lining of capillaries
Where are simple cuboidal epithelium found?
Kidney tubules, ducts, secretary portions of small glands, ovary surface
Where are simple columnar epithelium found?
Nonciliated lines the digestive tract and gallbladder, ciliated lines the small bronchi, uterine tubes, and parts of uterus
Function of cilia
Move things quickly across the cell surface
Function of microvilli
Increase surface area of cell
What kind of tissue can goblet cells be found in?
Simple columnar and pseuodstratified epithelia
Where can pseudostratified columnar epithelium be found?
Sperm carrying ducts, trachea, upper respiratory tract
What is the major role of stratified epithelia?
How is stratified epithelia named?
After its apical layer
What is the thickest epithelial tissue?
Where can keratinized epithelium be found?
Where can nonkeratinized epithelium be found?
Moist lining of body openings
Function of stratified squamous epithelia?
Protects underlying tissues that are subject o abrasion
Where is stratified cuboidal epithelia found?
Sweat glands, mammary glands, salivary glands
Where is stratified columnar epithelium found?
Very rare, in male urethra and large ducts of some glands
Function of transitional epithelia
Stretches and permits dissension of urinary organ
Where is transitional epithelia found?
lines ureters, bladder, part of urethra
Define endocrine glands
Ductless glands that secrete directly into surrounding tissue fluid, secrete hormones
Define exocrine glands
Ducts carry products of this gland to epithelial surface, includes: mucus secreting, sweat and oil, salivary, and liver/pancreas glands
What is a goblet cell?
Unicellular exocrine gland that produces mucin, protects and lubricates internal body surfaces
What is mucus made of?
Mucin and water
What are multicellular exocrine glands?
Two parts: epithelium walled duct for transportation and secretory unit that secretes, classified by structure and secretory unit
Simple tubular example
Simple branched tubular example
Compound tubular example
Simple branched alveolar example
Sebaceous gland (Oil)
Compound alveolar example