Pearson Anatomy and Physiology Chapter 4

tissues
groups of cells similar in structure that perform common or related function
histology
study of tissues
Four basic tissue types:
epithelial, connective, muscle, nervous
Fixed:
tissue is preserved
Sectioned
tissue is cut into slices thin enough to transmit light or electrons
stained
a dye is used to enhance contrast
artifacts
distortions in preserved tissue
epithelial tissue (epithelium)
a sheet of cells that covers the body surfaces or lines body cavities
covering and lining epithelium
located on external and internal surfaces ex.) skin
glandular epithelium
made up of secreting cells that make up the glands of the body
main functions of epithelial tissue:
1. protection
2. absorption
3. filtration
4. excretion
5. secretion
6. sensory reception
characteristics of epithelial tissue:
1. polarity
2. specialized contacts
3. supported by connective tissues
4. avascular, but innervated
5. regeneration
apical surface
upper free surface exposed to body exterior OR the cavity of an internal organ; some have microvilli, some have cilia
basal surface
lower attached surface which attaches to basal lamina
basal lamina
noncellular, adhesive sheet made of glycoproteins and collagen fibers; holds basal surface of epithelial cells to underlying cells
epithelial tissues fit closely together and form continuous sheets
–except for glandular epithelia
tight junctions and desmosomes
specialized lateral contact points that bind adjacent epithelial cells together
reticular lamina
layer of extracellular material that “belongs to” the underlying connective tissue; made of collagen protein fibers
basement membrane
formed by the reticular lamina and basal lamina;
-reinforces epithelial sheet, resists stretching, defines the epithelial boundary
avascular but innervated
-no blood cells are found
-nourished by diffusion
-epithelia are supplied by nerve fibers
regeneration
replacement of destroyed tissue with same type of tissue
damage of epithelial cells
caused by friction and hostile substances; leads to loss of apical-basal polarity and broken lateral contacts; cell division occurs
squamous
flattened and scale-like
cuboidal
box-like; cube
columnar
tall, column-like
simple epithelia
single layer thick
-absorption, secretion, or filtration
stratified epithelia
two or more layers
-high abrasion areas where protection is important
cell is named for:
the shape in top (apical) layer
Simple squamous:
single layer of flattened cells
Location: alveoli of lungs
Function: rapid diffusion
endothelium
simple squamous in lining of lymphatic vessels, blood vessels, and heart
mesothelium
simple squamous in lining of serous membranes in the ventral body cavity
simple cuboidal epithelium
single layer of cube-like cells; large spherical central nuclei
Location: kidney tubules
Function: secretion and absorption
simple columnar epithelium
single layer of tall cells; round to oval nuclei
–may contain goblet cells
Location:
-nonciliated: digestive tract
-ciliated: bronchi
Function: absorption, secretion of mucous, propelling mucous or reproductive cells by ciliary action
goblet cells
secrete mucous
stratified squamous epithelia
many cell layers; basal cells are cuboidal and apical cells are squamous or flat
Location: skin
Function: protection
Keratinized stratified squamous
-outermost layer is dead (no nuclei) and filled with keratin protein
-helps to keep skin dry (waterproofer)
non-keratinized stratified squamous
-forms linings in ares kept moist
-mouth, esophagus, vagina
stratified cuboidal epithelium
-rare in the body
-typically two layers
Location: large glands (sweat, mammary)
stratified columnar epithelium
-rare in the body
-can occur at junctions between two types of epithelia
Location: pharynx, male urethra, lining some glandular ducts
pseudostratified ciliated columnar epithelium
-single layer of cells that differ in height
–contains goblet cells
Location: trachea
Function: propel substances (mucous) and secretion of mucous
transitional epithelium
-basal cells are cuboidal or columnar
-apical cells are dome shaped when relaxed and squamous shaped when distended
Location: bladder and urinary system
Function: change shape and allow an increase volume of urine
gland
one or more cells that make and secrete a product
secretion
-aqueous fluid rich in proteins, lipids, or steroids that is the product of glands
-process of making and releasing a product
endocrine
internally secreting to another site in the body
exocrine
externally secreting to a site outside the body
Endocrine glands = ductless glands
secretions are released into surrounding interstitial fluid, which is picked up by circulatory system
–most are multicellular but some individual cells
hormones
messenger chemicals secreted via exocytosis into extracellular space and travel to target organ
exocrine glands
secretions are released onto body surfaces or into body cavities; more numerous than endocrine glands
-unicellular or multicellular
Products of exocrine glands:
mucous, sweat, oil, saliva, bile, digestive enzymes
Unicellular exocrine gland:
goblet cells and mucous cells
mucin
product of goblet cells or mucous cells that contains a glycoprotein that dissolves in water to form mucus
mucus
slimy coating that protects and lubricates (secrete via exocytosis)
multicellular exocrine glands
composed of a duct and secretory unit; surrounded by supportive connective tissue
-supplies blood and nerve fibers to gland
-forms capsule around gland
-extends into gland, dividing it into lobes
tubular gland
secretory cells from a tube
alveolar gland
secretory cells form sacs
tubuloalveolar
tube and sacs
simple glands
have unbranched ducts
compound glands
have branched ducts
merocrine
secrete products by exoctyosis as secretions are produced
holocrine
accumulate products within, then rupture
apocrine
accumulate products withing, but only apex ruptures (not sure if these exist in humans)
connective tissue
most abundant and widely distributed of primary tissues
functions of connective tissue
1. binding and support
2. protecting
3. insulating
4. storing reserve fuel
5. transporting substances
exctracellular matrix (ECM)
made up of ground substance and fibers
-non-living
-living cells of the tissue are embedded in it
-allows connective tissue to bear weight, withstand tension, and endure abuses
ground substance
unstructured gel-like material that fills space between cells
-interstitial fluid
-cell adhesion proteins
-proteoglycans (sugar proteins)
-water is trapped in varying amounts
collagen fibers
strongest and most abundant type
-provides high, tensile strength
-made up of collagen protein
elastic fibers
networks of long, thin, fibers
-contain elastin: rubber-like protein
-allow for stretch and recoil
reticular fibers
short, fine, hgihly branched collagenous fibers
-branching forms networks
-different chemistry and form from collagen fibers
-surround small blood vessels
-support soft tissue of organs
“blast” cells
immature form
-actively mitotic
-secrete ground substance and ECM fibers
fibroblasts
found in connective tissue proper
chondroblasts
found in cartilage
osteoblasts
found in bone
hematopoietic stem cells
found in bone marrow
“cyte” cells
mature form
-becomes part of the extracellular matrix
-maintains health
-less active
fat cells
store nutrients
white blood cells
tissue response to injury ex.) neutrophils, eosinophils, lymphocytes
mast cells
initiate local inflammatory response against foreign microorganisms
macrophages
phagocytic cells that “eat” dead cells and microorganisms
Loose connective tissue types
-areolar, adipose, reticular
areolar loose connective tissue
gel like matrix, all 3 fiber types
Location: dermal papilla (under the hypodermis of the skin)
Function: acts as a cushion, “packing material” between tissues
adipose loose connective tissue
sparse matrix, closely packed fat cells
Location: under skin, around organs
Function: insulation; support and protection
reticular loose connective tissue
loose network of reticular fibers; gel-like ground substance; reticular cells
Location: spleen and lymphatic system
Function: support of organs
dense connective tissue types:
regular, irregular, elastic
dense regular connective tissue
parallel collagen fibers, few elastic fibers, fibroblast cells
Location: attaches things; tendons and ligaments
Function: withstand stress in 1 direction
dense irregular connective tissue
irregularly arranged collagen fibers, some elastic fibers, fibroblast cells
Location: fibrous capsules of organs and joints (shoulder)
Function: withstand tension in multiple directions; structural strength
dense elastic connective tissue
dense tissue, high amount of elastic fibers
Location: artery walls
Function: allows recoil after stretch; maintains blood flow through arteries
Hyaline cartilage
most abundant cartilage, matrix appears glassy, chondrocytes lie in lacunae (cavities in the matrix)
Location: costal cartilage of ribs
Function: support and reinforcement; acts as a cushion; resists compression
elastic cartilage
more elastic fibers than hyaline
Location: ear
Function: maintain shape and structure with ability to flex
fibrocartilage
less firm matrix than hyaline, thick collagen fibers, alternating fibers and cells
Location: intervertebral discs
Function: absorbs compressive shock
bone tissue
osteons, lamellae, central canal, hard calcified matrix, collagen fibers
Location: bones
Function: support and protection, framework
osteons
closely packed structural units
lamellae
concentric rings of bony matrix
central canal
contains blood supply
bood
fluid in blood vessels (red and white blood cells, platelets, fluid matrix or plasma)
-most atypical connective tissue
-doesn’t connect things or give support
Location: within blood vessels
Function: transport gases, nutrients, and wastes
myofilaments
networks of actin and myosin filaments in muscle cells; enable movement and contraction
skeletal muscle
long, cylindrical cells; multinucleate; striations
Location: skeletal muscles attached to bone or skin
Function: voluntary movement
smooth muscle
spindle shaped cells; elongated; central nuclei; no striations
Location: walls of hollow organs (blood vessels, lymphatic vessels, bladder, respiratory tract, digestive tract, iris of the eye)
Function: involuntary muscle movement; propel substances along internal passageways by contracting
cardiac muscle
branched cells, striated, uninucleate, cells fit together at unique junctions (intercalated discs)
Location: walls of the heart
Function: involuntary muscle; propels blood when it contracts
nervous tissue
made of neurons (branching cells with soma, dendrites, and axon) and glial cells (varied structures that support)
Location: brain, spinal cord, nerves
Function:
-neurons: generate and conduct nerve impulses
-dendrites: respond to stimuli and pick up signal
-axon: transmits electrical impulses
-glial cells: act as a mesh to support, insulate and protect the neurons
covering and lining membranes
composed of at least two primary tissue types: an epithelium bound to underlying connective tissue proper layer
-cutaneous
-mucous
-serous
cutaneous membrane
(a.k.a. skin)
-keratinized stratified squamous epithelium (epidermis) attached to a thick layer of connective tissue (dermis)
-dry membrane
mucous membrane
(a.k.a. mucosae)
line body cavities that are open to the exterior
-epithelial sheet lies over layer of loose connective tissue called lamina propria
-moist membranes bathed by secretions (ex. urine)
-may secrete mucus
serous membrane
(a.k.a. serosae)
-found in closed ventral body cavities
-made of simple squamous epithelium (mesothelium) resting on thin areolar connective tissue
-moist membrane (cavity is filled with serous fluid)
parietal
line internal body cavity walls
visceral
cover internal organs
pleurae
lungs
pericardium
heart
peritoneum
abdomen
endothelium
simple squamous in lining of lymphatic vessels, blood vessels, and heart
mesothelium
simple squamous in lining of serous membranes in the ventral body cavity
simple cuboidal epithelium
endothelium
simple squamous in lining of lymphatic vessels, blood vessels, and heart
mesothelium
simple squamous in lining of serous membranes in the ventral body cavity
endothelium
simple squamous in lining of lymphatic vessels, blood vessels, and heart
endothelium