Studied by 8 people
What is tissue?
a group of cells that have a common embryonic origin and function together to carry out specialized activities
What is histology?
the study of tissues
What are the four basic types of tissues?
epithelial, connective, muscle, and nervous
What is epithelial tissue?
covers body surfaces, lines hollow organs, body cavities and ducts, forms glands
What is connective tissue?
protects and supports the body and its organs, binds organs together, stores energy reserved as fat, provides immunity
What is muscle tissue?
responsible for movement and generation of force
What is nervous tissue?
initiates and transmits action potentials that help coordinate body activities
What is a cell junction and what do they do?
point of contact between adjacent plasma membrane: form fluid-tight seals between cells, anchor cells together or to extracellular material, or act as channels which allow ions and molecules to pass from cell to cell within a tissue
What is a tight junction, where can you find it, and what does it do?
transmembrane proteins fuse together adjacent cells; located in epithelial tissue in the stomach, intestines, and urinary bladder; inhibits the passage of substances between cells
What is an adhering junction, where can you find it, and what does it do?
a dense layer of proteins (plaque); epithelial tissue; anchor cells together (help epithelial surfaces resist separation during various contractile activities)
What is a desmosome, where can you find it, and what does it do?
plaque and have transmembrane glycoproteins (cadherins); epidermal cells and cardiac muscle; contributes to stability of cells and tissue (prevent epidermal cells from separating under tension and cardiac muscle cells from pulling apart during contraction)
What is a hemidesmosome, where can you find it, and what does it do?
same as desmosomes however it anchors cells to the basement membrane
What is a gap junction, where can you find it, and what does it do?
connexins (transmembrane protein channels); anywhere that requires large area nervous control; enable nerve or muscle impulses to spread rapidly among cells
What is the major structural differences between epithelial and connective tissue?
epithelial tissue: many cells are tightly packed together with little or no extracellular matrix epithelial tissue has no blood vessels almost always form surface layers and are not covered by another tissue
connective tissue: a large amount of extracellular material separates cells have significant networks of blood vessels
What is the difference between epithelial and epidermis?
epithelial: one or more layers of cells which forms the covering of most internal and external surfaces of the body.
epidermis: top layer of skin
What some features of epithelial tissue?
cells arranged in densely packed sheets, many cell junctions, avascular, attaches to basement membrane, apical surface, mitosis
What is the basement membrane?
a thin, two-layered membrane consisting of the basal lamina (closer to epithelial) and reticular lamina (closer to underlying connective)
What are the four types of shapes of epithelial tissue?
squamous (flat), cuboidal (cube-like), columnar (rectangular), and transitional (variable)
What is simple squamous?
single layer of flat, scale-like cells; best for diffusion and filtration (lungs and kidneys), found in parts that are subject to little wear and tear (endothelium lines the heart and blood vessels, mesothelium lines the thoracic and abdominopelvic cavities)
What is simple cuboidal?
single layer of cube cells; performs the functions of secretion and absorption in ovaries, kidney tubules, and thyroid
What is simple columnar?
single layer of rectangular cells; non-ciliated: contain microvilli to increase surface area and rate of absorption in GI tract, ciliated: help move fluids or particles along a surface in bronchioles and fallopian tubes
What is pseudostratified columnar?
one layer but gives the appearance of many; all cells attached to basement membrane but some don't reach apical surface, non-ciliated: male urethra and epididymis, ciliated: upper respiratory tract
What is stratified squamous?
top layer of cells is flat, deeper layer of cells vary in shape from cuboidal to columnar; non-keratinized: mouth and esophagus, keratinized (very water-resistant protein): superficial layer of skin
What is stratified cubodial?
two or more layers of cuboidal cells; makes things, adult sweat glands
What is stratified columnar?
only top layer is columnar; conjunctiva of eye, part of urethra
What is transitional or urothelium?
several layers of cells that all vary in shape; capable of stretching and permits distention of an organ, lines most of urinary tract
What is a gland?
a single cell or mass of epithelial cells adapted for secretion
What is an endocrine gland, location, and function?
ductless; secretory product (hormones) enter the extracellular fluid and diffuse into the blood; pituitary glands in brain, pineal gland in brain, thyroid, etc.; regulate many metabolic and physiological activities
What is an exocrine gland, location, and function?
secrete products into ducts that empty at the surface of covering and lining epithelium or directly onto a free surface (skin or lumen of stomach); sweat, oil, digestive gland; produce substances such as sweat to help lower body temp, oil, earwax, saliva, or digestive enzymes
What is the most abundant tissue?
connective
What are the two basic elements of connective tissue?
cells and extracellular matrix
What are some general features of connective?
does not occur on free surfaces, is highly vascularized, and has nerve supply (except tendons and cartilage)
What is a fibroblast?
secretes fibres and ground substance
What is a macrophage?
develop from monocytes and are phagocytic
What is a plasmocyte?
develop into B lymphocytes/B cells
What is a mast cell?
produce histamine
What is a adipocyte?
store energy in the form of fat
What is a leukocyte?
white blood cell
What is extracellular matrix?
fibers and ground substance
What are collagen fibres?
collagen; very tough and resistant to stretch, allow some flexibility; found in bone, cartilage, tendons, and ligament
What are elastic fibres?
elastin; provide strength and stretch; found in skin, blood vessels, and lungs
What are reticular fibres?
collagen and glycoprotein; provide support in walls of blood vessels and form a strong, supporting network; fat cells, nerve fibres, and skeletal and smooth muscle fibres
What is loose connective?
fibres are loosely arranged between cells
What is dense connective?
fibres are thicker and more densely packed, but have fewer cells than loose connective tissue (tendon)
What is elastic connective?
strong and can recoil back to its original shape after being stretched
What is cartilage?
dense network of collagen fibers and elastic fibers firmly embedded in chondroitin sulfate
What is bone?
a matrix containing mineral salts and collagenous fibers and cells called osteocytes
What is blood?
has a liquid extracellular matrix called blood plasma and formed elements
What are the three types of cartilage?
hyaline, fibrous, and elastic
What is hyaline cartilage, location, and function?
resilient gel are ground substance, bluish-white, shiny, prominent chondrocytes in cartilage lacunae surrounded by perichondrium (except joints, growth plates, where bone lengthen); end of long bones, anterior end of ribs, nose, larynx, etc.; smooth surface for movement at joints, flexibility, and support
What is fibrous cartilage, location, and function?
chondrocytes among thick bundles of collagen fibres within extracellular matrix, no perichondrium; pubic symphysis, intervertebral discs, menisci, etc.; support and joining structures together
What is elastic cartilage, location, and function?
chondrocytes in a threadlike network of elastic fibres within extracellular matrix, perichondrium; epiglottis, auricle, eustachian; provides strength and elasticity, maintains shape
What is the most abundant cartilage?
hyaline
What is the weakest cartilage?
hyaline
What is the strongest cartilage?
fibrous
What is a membrane?
flat sheet of pliable tissue that covers or lines a part of the body
What are the two types of membranes?
epithelial and synovial
What are the three types of epithelial?
mucous, serous, and cutaneous
What is the mucous membrane?
lines cavities that open to the exterior (ex. GI tract); important aspect of the body’s defense mechanisms, acting as a barrier to pathogens; connective tissue layer called lamina propria
What is the serous membrane?
lines a body cavity that does not open directly to the exterior and covers the organs that lie within the cavity (ex. pleura); consist of parietal and visceral
What is the cutaneous membrane?
cover the outside of the body (ex. skin); the epidermis consists of keratinized stratified squamous epithelium and the dermis consists of areolar and dense irregular connective tissues
What is the synovial membrane?
line joint cavities, bursae, and tendon sheaths and do not contain epithelium, also secrete synovial fluid
What is muscle tissue?
fibres that provide, motion, posture, and heat
What are the three types of muscle tissue?
skeletal, cardiac, and smooth
What is skeletal muscle?
voluntary control; long, striated fibres
What is cardiac muscle?
involuntary control; branched, striated fibres
What is smooth muscle?
usually involuntary; non-striated fibres
What are the two types of cells in nervous tissue?
neurons and neuroglia
What do neurons consist of?
a cell body, dendrites, and axons
What is a neuron?
sensitive to stimuli, convert stimuli into nerve impulses, and conduct nerve impulses to other neurons, muscle fibers, or glands
What is a neuroglia?
protect and support neurons; sites of tumours of the nervous system
What are two types of excitable cells?
neurons and muscle fibres; respond to neurotransmitters
What is electrical excitability?
the ability to respond to certain stimuli by producing electrical signals which travel along the plasma membrane due to the presence of specific voltage-gated channels
How does each type of tissue respond to tissue repair?
epithelial: replaced by division of stem cells or undifferentiated cells
connective: bone has a continuous capacity to renewal while cartilage replenishes cells less readily
muscle: poor capacity for renewal
nervous: limited to no repair
What is fibrosis?
process of scar formation
What is granulation tissue?
actively growing connective tissue formed over extensive injuries
How do disorders effect epithelial tissue?
specific to individual organs
How do disorders effect connective tissue?
autoimmune in nature
Note
Flashcard