Chapter 4 Flashcards
Tissue
collection of similar cells and extracellular substances surrounding them
Four primary tissue types
epithelial, connective, muscle, nervous
histology
microscopic study of tissues
endoderm
inner germ layer, lines digestive tract
ectoderm
outer germ layer, forms skin (neuroectoderm- nervous sys)
mesoderm
middle germ layer, forms tissues (muscle, bone, blood vessels)
What are the 4 types of tissues derived from?
Each of the three germ layers (mesoderm, ectoderm, endoderm)
Epithelium
cells with little extracellular matrix. Covers surfaces. Basement membrane with no blood vessels.
Basement membrane
secreted by epithelial cells and attaches the epithelium to underlying tissue
Epithelial tissue functions
protect underlying structures, act as barriers, permit some substances to pass through layers, secrete substances, absorb substances
Simple epithelium
single layer of cells
- diffusion, filtration, secretion or absorption
stratified epithelium
two or more layers of cells
-protective role
pseudo stratified epithelium
single layer of cells that appear stratified
cells can be what 3 shapes
squamous (flat), cuboidal or columnar
stratified squamous epithelium can be..
nonkeratinized or keratinized
transitional epithelium is..
stratified with cells that can change shape from cuboidal to flattened
squamous cells function …
diffusion and filtration
cuboidal or columnar cells
have larger cell volume (many organelle) secrete or absorb
smooth free surface
reduces friction (mesothelium/endothelium)
microvilli
increase absorption (intestines)
cilia
moves materials across free surface (respiratory tract and uterine tubes)
transitional epithelium
has folded surface that allows cell to change shape and # of cells to change
cells are bound together by..
mechanically by glycoproteins, desmosomes and adhesion belts and to basement membrane.
tight junctions
form permeability barrier
gap junctions
allow intercellular communication
glands
organs that secrete
exocrine glands
secrete through ducts
endocrine glands
release hormones that are absorbed directly into blood
Glands are classified as…
-multicellular or unicellular
-mode of secretion
Goblet cells
unicellular glands
multicellular exocrine glands
-have ducts, simple or compound
-ducts are tubular or end in small sacs (acini/alveoli).
-Tubular - straight or coiled
Meocrine glands
-pancreas
-secrete substances as they are produced
apocrine glands
-mammary glands
accumulate secretions that are released when a portion of the cell pinches off
holocrine glands
-sebaceous glands
accumulate secretions that are released when the cell ruptures and dies
connective tissue
distinguished by extracellular matrix
- enclose/separate organs and tissues
-connect tissues to one another
-help support/move body parts
-store compounds
-cushion/insulate body
-transport substances
-protect against toxins and injury
extracellular matrix
Protein fibers, ground substance, fluid
connective tissue contains
adipocytes, mast cells, white blood cells, macrophages, and mesenchymal cells (stem cells)
-blast cells
form matrix
-cyte cells
maintain matrix
-clast cells
break matrix down
Collagen fibrils
join to form collagen fibers. resemble ropes. strong/flexible but resist stretching
reticular fibers
fine collagen fibers that form branching network that supports other cells and tissues
elastic fibers
structure like spring. after stretched, return to original shape
elastic fibers
structure like spring. after stretched, return to original shape
hyaluronic acid
ground substance major components
- makes fluids slippery
Proteoglycan
-ground substance major component
-aggregates trap water
-allows tissues to return to original shape
adhesive molecules
-ground substance major component
-hold proteoglycans together and to plasma membrane
connective tissue is classified according to..
type/proportions of cells, extracellular matrix fibers, ground substance and fluid
mesenchyme
Embryonic connective tissue
-consists of irregularly shaped cells and abundant matrix
-gives rise to adult connective tissue
-forms 3/4 week of development
Areolar connective tissue
-loose connective tissue
-different cell types, random arrangement of protein fibers with space b/w fibers. tissue fills space around organs and attaches the skin to underlying tissues
adipose tissue
adipocytes filled with lipid and little extracellular matrix (few reticular fibers)
-energy storage, insulation and protection.
-Yellow or brown (generate heat)
reticular tissue
network of reticular fibers.
framework of lymphatic tissue, bone marrow and liver
Dense regular connective tissue
-one direction fibers (strength with parallel).
-Collagenous (tendons/ligaments)
-elastic (ligaments of vertebrae)
dense irregular connective tissue
-fibers in all directions, strength in diff directions.
-collagenous(capsules of organs and dermis of skin)
-elastic (large arteries)
cartilage
-rigid matrix (protein fibers/proteoglycan aggregates)
-chondrocyte (located within lacunae)
hyaline cartilage
evenly dispersed collagen fibers (rigidity with some flexibility).
-ends of bones in joints, growing portion of long bones, embryonic skeleton.
fibrocartilage
collagen fibers in thick bundles
-withstand great pressure
-b/w vertebrae, jaw and knee
elastic cartilage
contains elastin, similar to hyaline. more flexible than hyaline.
-external ear
bone cells
osteocytes. located in lacunae surrounded by mineralized matrix (makes bone hard)
-spongey bone has spaces between trabeculae. compact bone is solid.
blood cells
suspended in fluid matrix
hemopoietic tissue
forms blood cells
muscle tissue
ability to contract
skeletal muscle
-striated voluntary
-muscle attaches to bone (responsible for body movement)
-long/cylindrical with many peripheral nuclei
cardiac muscle
-striated involuntary
-cylindrical, branching cells with single central nucleus
-found in heart, responsible for pumping blood through circulatory system
smooth muscle
-nonstriated involuntary
-forms walls of hollow organs, iris of eye
-spindle shape cell with single central nucleus
nervous tissue
conducts electrical impulses and composed of neurons (conductive cells) and glia (support cells)
dendrites
receive electrical impulses
axons
conduct electrical impulses
multipolar neuron
several dendrites and an axon
bipolar neuron
one dendrite and one axon
pseudo-unipolar neuron
one axon
Tissue membrane details
-1 external (skin)
-3 internal (mucous, serous, synovial)
mucus membrane
-epithelial cells, basement membrane, lamina propria. Sometimes smooth muscle cells.
-line cavities that open up to the outside and often contain mucous glands - secrete mucous.
serous membrane
line cavities that do not open to the exterior and do not contain glands but do secrete serous fluid
synovial membrane
formed by connective tissue, line joint cavities and secrete a lubricating fluid
inflammation response symptoms
redness, heat, swelling, pain and disturbed function
- isolates injurious agents from rest of body and destroys agents
tissue repair occurs by
regeneration or replacement
-substitution of viable cells for dead ones
labile cells
divide throughout life and regenerate
stable cells
do not ordinarily divide after growth is complete but can regenerate if necessary
permanent cells
cannot replicate. if killed, permanent tissue is repaired by replacement
primary union tissue repair
edges of would close together
secondary union tissue repair
edges of wound are far apart
age-related tissue changes
reduced rates of cell division and changes in extracellular fibers
collagen fibers with age
less flexible and have less strength
elastic fibers with age
become fragmented and less elastic
