Chapter 5 Flashcards
Tissue Organization
epithelial tissue (epithelium) is composed of
one or more layers of closely packed cells, with little to no extracellular matrix between these cells.
Extracellular matrix (ECM) is
a network of biological macromolecules that provides structural and biochemical support to surrounding cells.
Epithelial tissue covers _____, lines ______, and forms ______
surfaces of the body
the body cavities and organs
glands
All epithelia exhibit six common characteristics:
Cellularity: minimal ECM between tightly packed cells
Polarity: containing an apical (top/superficial) and basal (bottom/deep) surface
Attachment to basement membrane: a thin layer made of collagen, glycoproteins, and proteoglycans. Acts to adhere the epithelia to the underlying connective tissue
Avascularity: epithelial tissues receive blood/nutrients from underlying CT
Extensive innervation: epithelial tissues are enriched with many nerves to detect environmental changes
High regeneration capacity: epithelial tissues often protect against damage, so the cells must be replaced often
four general functions of epithelial tissue
Physical protection: protection against dehydration, abrasion, and destruction
Selective permeability: range of permeability to allow for selection of water and ions, either staying in or out
Secretory ability: specialized epithelial cells called glands produce secretions for specific functions
Sensation processing: nerve endings allow for sensations to be felt and processed, such as pain, temperature, touch, and pressure
three layer classifications of epithelia
simple
stratified
pseduostratified
simple epithelia is
only one true layer of cells
Stratified epithelia is
more than one true layer of cells
Pseudostratified epithelia is
more than one layer of cell but there is only one true layer, despite how it looks
how to differentiate between stratiified and pseudostratified epithelium?
In pseudostratified, cells will
reach the apical membrane but not the basal membrane, giving the stratified appearance.
one true layer of cells means?
that the cells begin at the basal membrane.
four shape classification for epithelia
squamous
cuboidal
columnar
transitional
squamous epthelia is
flat, wide, and irregular in shape
cubodial epithelia is
same height as width, cube-like
columnar epithelia is
taller than wide, column-like
transitional epithelia can
change shape when stretched
simple squamous epithelium function
thin to allow for diffusion and filtration, secretion in serous membrane
simple squamous epithelium location
alveoli in lungs, blood vessel lining, serous membranes
simple cuboidal epithelium location
absorption and secretion
simple cuboidal epithelium function
kidney tubules, thyroid gland follicles, ovarian surface, exocrine gland ducts/secretory regions
ciliated simple columnar epithelium location
bronchioles of lungs, fallopian tubes
ciliated simple columnar epithelium function
secretion of mucin, movement of mucus, movement of oocyte
nonciliated simple columnar epithelium function
absorption and secretion
nonciliated simple columnar epithelium location
GI tract lining (most)
ciliated Pseudostratified columnar epithelium function
protection, secretion of mucin, movement of mucus
ciliated Pseudostratified columnar epithelium location
nasal cavity, pharynx, larynx, trachea, bronchi
nonciliated Pseudostratified columnar epithelium function
protection
nonciliated Pseudostratified columnar epithelium location
parts of male urethra and epididymis
keratinized Stratified squamous epithelium function
protection from abrasion
keratinized Stratified squamous epithelium location
epidermis of skin
nonkeratinized Stratified squamous epithelium function
protection from abrasion
nonkeratinized Stratified squamous epithelium location
oral cavity, pharynx, larynx, esophagus, vaginal lining, anal lining
Stratified cuboidal epithelium function
protection and secretion
Stratified cuboidal epithelium location
exocrine gland ducts and ovarian follicles
Stratified columnar epithelium location
large salivary gland ducts, conjunctiva of the eye, membranous lining of the urethra
Stratified columnar epithelium function
protection and secretion
Transitional epithelium function
accommodation of urine volume changes
Transitional epithelium location
urinary bladder lining, ureters, urethra
Glands are
individual cells or multicellular organs composed mainly of epithelial tissue that secrete substances for either use for or elimination out of the body
five substances glandular secrtetions may contain
Mucin (glycoprotein for lubrication)
Ions
Hormones
Enzymes
Urea (a waste product created by nitrogen balance in the body)
Endocrine glands
ack ducts and secrete hormones into the blood to be transported throughout the body. These hormones are chemical messengers that influence cell communication.
Exocrine glands originate from
invagination of the epithelium that burrows into the underlying connective tissue.
exocrine glands connect with the epithelium by using a
duct, a tube lined with epithelial tissue that directs the gland secretions onto the epithelial surface.
Anatomic form classification of exocrine glands
simple or compound
simple exocrine glands have
unbranched ducts
compound exocrine glands have
branched ducts
types of simple exocrine glands
Simple tubular
Simple branched tubular
Simple coiled tubular
Simple acinar
Simple branched acinar
types of compound exocrine glands
compound tubular
compound acinar
compound tubuloacinar
three methods of secretion of exocrine glands
merocrine
apocrine
holocrine
merocrine secretions are
packaged into secretory vesicles and released by exocytosis
Merocrine examples
tear glands, salivary glands, sweat glands, pancreas, and gastric glands
Apocrine secretory material is
produced when the cell’s apical portion is pinched off, releasing cytoplasmic contents. The cell must repair itself to repeat the process.
Holocrine cells accumulate
the secretory material and then the entire cell disintegrates.
Apocrine examples
mammary glands, ceruminous glands of the ear (earwax)
Holocrine examples
sebaceous glands (oil producing glands of the skin)
Connective tissue (CT) is
the most diverse, abundant, and widely distributed tissue in the body.
connective tissue functions
support, protect, and bind organs
six forms of CT
Tendons (muscle to bone)
Ligaments (bone to bone)
Adipose (fat tissue)
Cartilage
Bone
Blood
CT two characteristics that have ranges
Vascularity (none to very)
Regenerative capacity (none to fast)
ALL CT origin is from
mesenchyme, an embryonic connective tissue.
resident cells are
stationary and permanently housed within the connective tissue.
wandering cells
move continuously throughout the connective tissue proper and are components of the immune system. They may also help repair damaged ECM.
four resident cells of connective tissue proper
Fibroblasts
adipocytes
mesenchymal cells
macrophages
fibroblasts are
most abundant cell; flat with tapered ends. Produces fibers & ground substance of ECM.
adipocytes are
fat cells, found in small clusters in some CT proper types. If found in large clusters, this is adipose tissue.
mesenchymal cells are
embryonic stem cell of CT. These cell divide when the CT is damaged.
macrophages are
large, irregularly shaped cell, arise from white blood cells. Responsible for phagocytosis and immune system responses.
wandering cells are mainly
leukocytes (white blood cells).
three main protein fibers found in CT
collagen
reticular
elastic
collagen fibers are
unbranched, cable-like, long fibers that are strong, flexible, and resistant to stretching. Makes up 25% of the body’s protein.
reticular fibers are
similar to collagen but much thinner, different form of collagen. Provides a tough but flexible framework.
elastic fibers
contains elastin, a protein. Creates branching fibers and they appear wavy under a microscope. The elastin allows for the fibers to stretch and return to their original shape.
Collagen fibers are found
throughout tendons and ligaments
Reticular fibers are found
in organs: lymph nodes, spleen, and liver.
Elastic fibers are found
abundant in the skin, arteries, and lungs.
Mesenchymal CT function
origin for all CTs
Mesenchymal CT location
throughout the body of the embryo and fetus
Mucous CT function
supports structures in the umbilical cord
Mucous CT location
umbilical cord of fetus
ONLY
mucous CT is also called
wharton’s jelly
connective tissue proper is
a term that covers both loose and dense connective tissues.
fluid connective tissue is
blood
Supportive connective tissue includes
bone and cartilage
all connective tissue share three components
Cells (mesenchymal, macrophage, adipocyte, fibroblast)
Protein fibers (elastic, collagen, or reticular)
Ground substance (gel-like substance made of mostly water and large organic molecules)
Areolar CT function
protection of tissues and organs, binds skin and epithelia to deeper tissues, provides space for blood vessels and nerves
Areolar CT location
dermis of skin, subcutaneous layer of skin, surrounds organs, nerve cells, some muscle cells, and blood vessel walls
adipose CT function
energy storage, insulation, cushion, protection
adipose CT location
subcutaneous layer, surrounds and covers some organs
reticular CT function
provides stroma (supportive framework) to lymphatic organs
reticular CT location
spleen, lymph nodes, red bone marrow
Dense regular CT function
attaches bone to bone (ligaments), muscle to bone (tendons), resists unidirectional stress
Dense regular CT location
tendons, ligaments
Dense irregular CT function
resists stress in all directions
Dense irregular CT location
reticular layer of dermis, epimysium (SK muscle), epineurium (nerves), periosteum (bone), perichondrium (cartilage), some organ capsules
Elastic CT function
stretch and recoil
Elastic CT location
elastic arterial walls, trachea, vocal cords
Hyaline Cartilage function
support, most of fetal skeleton
Hyaline Cartilage location
tip of nose, bronchi, larynx, costal cartilage, epiphyseal (growth) plates
Fibrocartilage function
weight bearing cartilage, resists compression, shock absorption
Fibrocartilage location
intervertebral discs, pubic symphysis, menisci of knee
Elastic Cartilage function
shape maintenance allowing for extensive flexibility
Elastic Cartilage location
external ear, epiglottis
Bone function
body movement levers, support of soft structures, organ protection, calcium and phosphorus storage, blood cell formation (spongy bone in bone marrow)
blood function
RBCs transport oxygen and CO2, WBCs protect against infection, platelets for blood clotting, plasma transports nutrients and waste
blood location
blood vessels and heart
an organ is
a structure composed of two or more tissue types that work together to perform specific, complex functions.
organ example (and why)
Stomach
Contains all four tissue types: epithelial, connective, muscular, and nervous tissue.
All of these tissue types must work together to perform specific functions:
Secretion of chemical/enzymes for digestion (glands)
Housing of blood vessels, shape, and support (CT)
Contraction and relaxation for mechanical mixing of contents (muscle)
Stimulation and control of muscle contraction and glandular secretions (nervous/nerves)
Body membranes are formed from
an epithelial layer that is bound to an underlying connective tissue
body membrane functions
line body cavities or a joint surface, cover the viscera, or cover the external surface of the body
four types of body membranes
mucous
serous
cutaneous
synovial
mucous membranes line
passageways and compartments that eventually open to the external environment. They perform absorptive, protective, and/or secretory functions.
serous membranes line
lines body cavities that typically don’t open to the external environment, covers the surface of many organs. Produce serous fluid for lubrication.
cutaneous membranes cover
covers the external body surface. Composed of keratinized epithelium and protects against abrasion and water loss.
synovial membranes are
specialized connective tissue that secretes synovial fluid. For friction reduction like serous fluid.
mucosa example
digestive, urinary, reproductive tracts
serous membrane example
pericardium of the heart, pleura of the lungs, peritoneum of the abdominal organs
cutaneous membrane example
skin
synovial membrane example
joints of the body like the knees
hypertrophy
is an increase in size of the existing cells in a tissue, but the number of cells remains constant.
muscle cells grow in size when undergoing long-term rigorous exercise regimen.
Hyperplasia
an increase in the number of cells in a tissue.
callus on the palm of the hand
Atrophy
shrinkage of tissue by a decrease in either class size or cell number.
if a muscle group is unused for a period of time (broken bone with a cast) the muscle cells will begin to shrink.
Metaplasia
an adaption of the cells to a change in the external environment.
the epithelium of the trachea will convert from pseudostratified ciliated columnar epithelium to nonkeratinized stratified squamous epithelium in chronic smokers (and back to normal when they quit)
Dysplasia
abnormal tissue development in an area.
cervical dysplasia from HPV, can turn into cancer.
Neoplasia
abnormal, out of control, tissue growth.
tumors, either benign or cancerous. Benign growths do not spread and don’t invade other body systems.
Necrosis
tissue death as a result of inflammatory response to irreversible tissue damage.
