name the four primary classes into which all adult tissues are classified
epithelial, connective, nervous , and muscular tissues
name the three embryonic germ layers and some adult tissues derived from each
ectoderm, endoderm, mesoder
Ectoderm
outer layer, gives rise to epidermis and nervous system
Endoderm
Inner layer, gives rise to mucous membrane lining digestive and respiratory tracts, digestive glands
Mesoderm
middle layer, becomes gelatinous tissue called mesenchyme
wispy collagen fibers and fibroblasts in gel matrix
gives rise to cartilage, bone, blood, muscle
visualize the three-dimensional shape of a structure from a two-dimensional tissue section
longitudinal section , cross section (transverse section), oblique section
longitudinal section
tissue cut on its long axis
cross section (transverse section)
tissue cut perpendicular to long axis of organ
oblique section
tissue cut at angle between cross and longitudinal sections
structure of epithelia
sheets of closely adhering cells, one or more cells think
coves body surfaces and lines body cavities
upper surface usually exposed to the environment or an internal space in the body
constitutes most glands
avascular (does not have blood vessels)
functions of epithelia
protect deeper tissues from injury and infection
produce and release chemical secretions
excrete waste
absorb chemicals including nutrients
selectively filter substances
sense stimuli
describe the junctions that hold cells and tissues together
cell junctions
tight junctions
desmosomes
gap communicating
cell junction
connections between two cells
communication, resist mechanical stress, control what moves through the gaps between them
tight junctions
linkage between two adjacent cells by transmembrane cell-adhesion proteins
seals off intercellular space, making it difficult for substance to pass between cells
desmosomes
patch that holds cells together (like a clothing snap)
keeps cells from pulling apart, resist mechanical stress
(hemidesmosomes) half anchors basal cells of an epithelium to underlying basement membrane
gap communicating junction
formed by ring-like connexons
6 transmembrane proteins
ions, nutrients and other small solutions pass between cells
located in the cardiac and smooth muscle, embryonic tissue, lens and cornea
glands
cell or organs that secretes substance for use elsewhere in the body or releases them from elimination from the body
epithelial tissue
connective tissue
secretion
products useful to the body
saliva
Excretion
waste product
urination
endocrine gland
have no ducts; secrete hormones directly into blood
thyroid, adrenal, and pituitary glands
exocrine glands
maintain their contact with surface of epithelium by way of a duct
(external) sweat, tear glands
(internal) pancreas, salivary glands
unicellular glands
found in an epithelium that is predominantly nonsecretory
can be exocrine or endocrine
goblet cells
secrete mucus
capsule
connective tissue covering of exocrine gland
sac around the heart
Stroma
connective tissue framework of the gland
supports and organizes glandular tissue
parenchyma
cells that perform the tasks of synthesis and secretion
framework, structure
Tubular (classification of glands)
narrow secretory portion
-eccrine sweat gland
acinar (classification of glands)
secretory cells form dilated sac (acinus or alveolus)
mammary gland
tubuloacinar (classification of glands)
both tubular and acinar portions
serous glands
produce thin, watery secretions
milk, tears, digestive juices
mucous glands
produce glycoproteins, mucin, which absorbs water to form musuc
goblet cells: unicellular musous glands
Mixed glands
contain both serous and mucous cell types and produce a mixture of the two types of secretions
tears can change and saliva glands
apocrine secretion
lipid droplet covered by membrane and cytoplasm buds from cell surface (budding)
milk fat secretion
merocrine secretion
(used by eccrine glands)
uses vesicles that release their secretion by exocytosis
tear glands, pancreas, gastric glands
lowest lipid concentration
holocrine secretion
cells accumulate a product until they disintegrate
secret a mixture of cell fragments and synthesized substances
oil glands of scalp adn skin, gland of eyelids
cutaneous membrane (the skin)
largest membrane in the body
stratified squamous epithelium (epidermis) resting on layer of connective tissue (dermis)
relatively dry layer serves protective function
compound membrane
mucous membrane (mucosa)
lines passages that open to the external environment (digestive tract)
absorptive, secretory, and protective functions
often has mucus producing goblet cells
compound
serous membrane (serosa)
internal membrane
double membrane
produces serous fluid that arises from blood
covers organs and lines walls of body cavities
tissue growth
increasing the number of cells or size of existing cells
hyperplasia
growth through cell multiplication
hypertrophy
enlargement of preexisting cells
muscle growth through exercise
accumulation of body fat
neoplasia
development of a tumor
composed of abnormal, nonfunctional tissue
differentiation
development of more specialized form and function by unspecialized tissue
embryonic mesenchyme becoming cartilage and bone
metaplasia
changing from one type of mature tissue to another
simple cuboidal tissue of vagina before puberty changes to stratified squamous after puberty
developmental plasticity
ability of a stem cell to give rise to a diversity of mature cells types
totipotent
having the potential to develop into any type of fully differentiated human cell including accessory organs of pregnancy
most plasistity
cells of the very early embryo
twins separate in cells
pluripotent
can develop into a type of cell in the embryo (but not accessory organs of pregnancy)
cells of inner cell mass of embryo (blastocyts)
multipotent
able to develop into two or more cell lines
bone marrow stem cells
unipotent
produce only one cell type
cells giving rise to sperm
induced pluripotent stem cells (iPS Cells)
starts as a multipotent stem cell, reprogrammed to mimic a pluripotent stem cell
stem cells
adult
undifferentiated cells that give rise to keratinocytes
in deeper layers of the epidermis (stratum basale)
high metabolism= close to the source of nutrition
embryonic stem cells
pluripotent stem cells
can divide more or become any type of cell in the body
can be used to regenerate or repair diseased tissue and organs
regeneration
replacement of dead or damaged cells by the same type of cells as before
restores normal function
ex: minor skin or liver injuries
fibrosis
replacement of damaged cells with scar tissue
scar holds organs together, but does not restore function
repair of severe cuts and burns, scarring of lungs in tuberculosis
simple squamous epithelium
single row of thin cells
permits rapid diffusion or transport of substances
secretes serous fluid
location: alveoli, glomeruli, endothelium, and serosa
simple cuboidal epithelium
single layer of square or round cells
absorption and secretion, mucus production and movement
location: liver, thyroid, mammary and salivary glands, bronchioles, and kidney tubules
simple columnar epithelium
single row of tall, narrow cells
oval nuclei in basal half of cell
brush border of microvilli, ciliated in some organs, may possess goblet cells
absorption and secretion; secretion of mucus
location: lining of GI tract, uterus, kidney, and uterine tubes
pseudostratified epithelium
looks multilayered, but all cells touch basement membrane
nuclei at several layers
has cilia and goblet cells
secretes and propels mucus
location: respiratory tract and portions of male urethra
keratinized stratified squamous epithelium
multiple cell layers; cells become flat and scaly toward surface
resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms
location: epidermis; palms and soles heavily keratinized
non-keratinized stratified squamous epithelium
same as keratinized epithelium without surface layer of dead cells
resists abrasion and penetration of pathogens
locations: tongue, oral mucosa, esophagus, and vagina
stratified cuboidal epithelium
two or more cell layers; surface cells square or round
secretes sweat; produces sperm, produces ovarian hormones
locations: sweat gland ducts; ovarian follicles and seminiferous tubules
transitional epithelium
multilayered epithelium with surface cells that change from round to flat when stretched
allows for filling of urinary tract
location: ureter and bladder
functions of connective tissue
connecting organs
support
physical protection
immune protection
movement
storage
heat production
transport
connecting organs
tendons and ligaments
support
bones and cartilage
physical protection
cranium, ribs, sternum
immune protection
white blood cells attack foreign invaders
movement
bones provide lever system
storage
fat, calcium, phosphorus
heat production
metabolism of browns fat in infants
transport
blood
cells of fibrous connective tissue
fibroblasts
macrophages
leukocytes
plasma cells
mast cells
adipocyte
fibroblast
produce fibers and ground substance of matrix
macrophages
phagocytize foreign material and activate immune system when they sense foreign matter (antigens)
leukocyte
white blood cells
neutrophils attack bacteria
lymphocytes react against bacteria, toxins and other foreign agents
plasma cells
synthesize antibodies
mast cells
often found alongside blood vessels
secrete heparin to inhibit clotting
secrete histamine to dilate blood vessels
adipocytes
store triglycerides (fat molecules)
collagenous fibers
collagen is most abundant of the body’s proteins 25%
tough, flexible, and stretch-resistant
tendons, ligament, and deep layer of the skin are mostly collagen
less visible in matrix of cartilage and bone
reticular fibers
thin collagen fibers coated with glycoprotein
form framework of spleen and lymph nodes
elastic fibers
thinner than collagenous fibers
branch and rejoin each other
made of protein called elastin
allows stretch and recoil
areolar tissue
loosely organized fibers, abundant blood vessels
underlies epithelia, in serous membranes, between muscles, passageways for nerves and blood vessels
reticular tissue
mesh of reticular fibers and fibroblasts
forms supportive stroma (framework) for lymphatic organs
found in lymph nodes, spleen, thymus, and bone marrow
dense regular connective tissue
densely packed, parallel collagen fibers
compressed fibroblast nuclei
elastic tissue forms wavy sheets in some locations
tendons attach muscles to bones and ligaments home bones together
dense irregular connective tissue
densely packed, randomly arranged, collagen fibers and few visible cells
withstands unpredictable stresses
location: deeper layer of skin; capsules around organs
atrophy
shrinkage of tissue through loss in cell size or number
senile atrophy through normal aging
disuse atrophy from lack of use
necrosis
pathological tissue death due to trauma, toxins, or infections
infarction
sudden death to tissue when blood supply is cut off
gangrene
tissue necrosis due to insufficient blood supply (usually involved infection)
dry gangrene
common complication of diabetes
wet gangrene
liquefaction of internal organs with infection
gas gangrene
usually from infection of soil bacterium that results in hydrogen bubbles in tissues
apoptosis
programmed cell death
adipose tissue
Fat, tissue in which adipocytes are the dominant cell type
primary energy storage, insulation, cushioning
subcutaneous fat and organ packing
brown fat of juveniles produces heat
white fat
main type of fat in adults
provides thermal insulation
cushions organs such as eyeballs, kidneys
contributes to body contours- female breasts and hips
brown fat
in fetuses, infants, children
color comes from blood vessels and mitochondrial enzymes
heat-generating tissue
hyaline cartilage
clear, glassy appearance because of fineness of collagen fibers
eases joint movement, holds air way open, moves vocal cords, growth of juvenile long bone
location: articular cartilage, costal cartilage, trachea, larynx, fetal skeleton
Elastic cartilage
cartilage containing abundance of elastic fibers
covered with perichondrium
provides flexible, elastic support
location: external ear and epiglottis
fibrocartilage
cartilage containing large, coarse bundles of collagen fibers
resist compression and absorbs shock
location: pubic symphysis, menisci, and intervertebral discs
compact bone
arranged in cylinders that surround central canals that run longitudinally through shafts of long bones
blood vessels and nerves travel through central canal
bone matric deposited in concentric lamellae
excitability
ability to respond to stimuli by changing membrane potential
nervous and muscular tissue