Human Anatomy - Chapter 4

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