Tissue Types Flashcards
Epithelial tissue
forms barriers
covers exposed body surfaces
lines hollow organs, body cavities, and gland ducts
forms glands
connective tissue
links tissues and organs together
provides structural and metabolic support
stores energy
forms immune system
few cells
lots of extracellular matrix
muscle tissue
specialized for contraction
generates force
maintains body temperature
elongated cells - contract + generate force
nervous tissue
receives, processes, and integrates signals from within the body and from external environment
generates and transmits impulses that control and integrate the various functions of the body
highly asymmetrical cells with long cytoplasmic processes
transmit electrical signals via ionic conduction
characteristics of epithelia
continuous
avascular
rest on basal lamina
little extracellular matrix
polarized
simple
single layer of cells
stratified
2+ layers of cells
squamous
flat cells
cuboidal
cell height equals width
columnar
cells are taller than wide
simple squamous epithelium
reduces friction, controls vessel permeability, performs absorption and secretion
mesothelium
simple squamous epithelium
lines body cavities
endothelium
simple squamous epithelium
lines heart chambers and blood vessels
simple cuboidal epithelium
provides limited protection; secretion and/or absorption
found in glands, ducts, portions of kidney tubules, thyroid gland
simple columnar epithelium
nuclei of cells are aligned
protection, secretion, absorption
lines digestive tract, fallopian tubes, and excretory ducts
stratified squamous epithelium
outermost layer is squamous
provides physical protection against abrasion, pathogens, and chemical attack
found where mechanical stresses are severe: outer layer of skin, mouth, throat, esophagus
stratified cuboidal epithelium
2-3 layers of cells
rare - line larger ducts of exocrine glands: sweat + mammary glands
protection, secretion and absorption
stratified columnar epithelium
multiple layers
rare - large excretory ducts: pharynx, urethra, anus (transitional zones)
protection
pseudostratified columnar epithelium
nuclei are not aligned
all cells touch basal lamina but not all reach luminal surface
found in respiratory system + male reproductive tract
protection, secretion
transitional epithelium
multiple layers of cells
outermost cells are large and dome-shaped
found in urinary tract: bladder, renal pelvis, ureters
permit expansion and recoil after stretching
glands
made of epithelial cells
form by growth of epithelial cells into underlying connective tissue
exocrine glands
release secretions through ducts onto epithelial surfaces
secretory cells remain connected to surface by duct
endocrine glands
lack ducts
secrete hormones into blood
merocrine secretion
normal exocytosis
messengers are manufactured in nucleus → sent to cell surface → bind to membrane → release
apocrine secretion
apical surface is pinched off
holocrine secretion
entire cell is released
division of cell → mature cell dies and becomes secretory product
connective tissue matrix
ground substance (hydrated gel) + fibres
collagen fibres
form bundles that provide tensile strength
reticular fibres
form branching network that supports cells
elastic fibres
thin branching fibres that function like rubber bands
fibroblasts
secrete ground substance and fibres
macrophages
ingest debris and function in immune response
classification of connective tissue
density of fibres
types of fibres
preponderance of specific cell type
mesenchyme
found in developing embryo
remain as stem cells in adult tissue
loose connective tissue
packing material - fill spaces between organs = cushioning + support
abundance of ground substance or cells
few fibres
areolar, adipose, reticular
areolar connective tissue
most common, least specialized
links together other tissues and organs
open framework
permits independent movement
phagocytic cells provide defense against pathogens
adipose connective tissue
fat tissue
forms deposits in specific areas of body
padding, insulation, energy storage
dense connective tissue
abundance of fibers
little ground substance, few cells
dense irregular connective tissue
fibres unaligned
forms dermis of skin, organ capsules, sheaths around bones, muscles, and nerves
provides maximal protection - strength to resist force applied from all directions
dense regular connective tissue
fibers aligned in one direction
forms tendons and ligaments
provides firm attachment, conducts pull of muscles, reduces friction between muscles, stabilizes positions of bones
membranes
epithelium + connective tissue
line surfaces, cavities, and hollow organs
mucous membrane
lines airway to trap particulates
epithelium - lamina propria (areolar tissue)
epithelium secretes mucous
serous membrane
delicate lining of pleural cavities
serous fluid = thin + lubricating
transudate - epithelium - areolar tissue
cutaneous membrane
skin
epithelium - areolar tissue + dense irregular connective tissue
= epidermis + dermis
synovial membrane
inside of joint capsule
synovial fluid = sticky → decrease friction
epithelium - areolar tissue (fibroblasts + adipocytes) - joint capsule
fluid connective tissue
blood + lymph
blood
blood cells + plasma
plasma forms fluid matrix
lymph
lymphocytes + lymph fluid
lymph fluid = dilute solution of proteins and excess interstitial fluid
supporting connective tissue
cartilage + bone
extensive incompressible matrix
support soft tissues of the body
skeletal muscle tissue
attaches to bones
striated - pattern of bands
voluntary contraction
long cylindrical multinucleated tubes
distinct cross-banding patterns (2 proteins)
stabilizes + moves articulated skeleton
smooth muscle tissue
associated with viscera
non-striated
involuntary contraction (automatic)
cells are short + spindle-shaped; contain single nucleus
non striated - interact with each other
forms walls of blood vessels + hollow organs
specialized for slow sustained contractions
cardiac muscle tissue
heart
striated - pattern of bands
involuntary contraction
short, branched, striated cells with single nuclei
specialized for continuous, rhythmic contraction
multipolar neuron
one cell body
many dendrites
only one axon
