lecture 2: tissues Flashcards
what are tissues
groups of cells with a common structure and function
name 4 main categories of tissue
nervous
muscle
epithelial
connective
describe nervous tissue generally
brain
spinal cord
nerves
describe muscle tissue briefly
cause movement
anywhere that moves (skeletal, cardiac, smooth)
describe epithelial tissue generally
protects
secretes
absorbs
filters
lines
describe connective tissue generally
bones
fat
blood
tendons
all filler tissue
how to know it’s epithelial tissue visually
usually see air on one side or air somewhere
where do you find epithelial tissue
everywhere
describe locations of epithelial tissue
lining of hollow organs
covering of skin surface
glandular secretory tissue (saliva, sebaceous glands, sweat)
describe functions of epithelial tissue
protection (mechanical injury, microorganisms, fluid loss)
absorption
secretion
filtration
what is epithelial tissue classified by
cell shape and number of layers
name and describe 3 types of shapes of epithelial tissue
squamous - flat nucleus, flattened
cuboidal - cube shape, round nucleus
columnar - column like, oval nucleus
describe the 2 types (numbers) of layers of epithelial tissue
simple
stratified (combined together)
what is the apical surface
contacts air food blood etc
top
what is the basal surface
base
glues epithelial tissue to underlying tissue
how many types of epithelial tissue are there
8
name all 8 types of epithelial tissue
simple squamous
simple cuboidal
simple columnar
pseudo stratified columnar
stratified squamous
stratified cuboidal
stratified columnar
transitional epithelium
what’s the catch with pseudostratified columnar
looks stratified but is simple
describe structure function location of simple squamous
s - single layer of flattened cells (cytoplasm is sparse
f - rapid diffusion exchange
l - kidney glomeruli, lung alveoli, capillaries
visually describe simple squamous
very thin
simple, nuclei visible
thin strings
describe structure function location of simple cuboid
s - single layer of cuboidal cells
f - secretion and absorption
l - ducts of glands, kidney tubules
visually describe simple cuboid
can see cube shapes with nuclei
has blood (in capillary)
connective tissues glue tubules together
describe structure function location of simple columnar
s - single layer of tall closely packed cells, some have cilia or microvilli
f - secretion of enzymes and mucus (goblet cells, absorption (microvilli)
l - digestive tract, gallbladder, gland ducts, bronchi, uterine tubes
visually describe simple columnar
long cells
connective tissue
goblet cells (look empty ish but have mucus)
microvilli maximized surface area
describe structure function location of pseudo stratified columnar
s - single layer of cells that vary in height, often ciliated
f - secretion of mucus (goblet cells), cilia beat to move mucus
l - upper respiratory tract, duct glands, tubules in testes
visually describe pseudo stratified columnar
look for cilia, elongated cells and goblet cells
all cells touch bottom (simple) but nuclei at different heights so appears stratified
describe structure function location of stratified squamous
s - apical later is squamous (lower layers are columnar or cuboidal)
f - protect abasing wear and tear (friction)
l - skin, mouth, esophagus (keratinized cells on skin surface (dead) and non keratinized in moist areas)
visually describe stratified squamous
flat nuclei on top (apical cells gives names)
become round towards bottom
basement membrane - basal cells actively undergo mitosis to replace cells on top
connective tissue
stratified squamous lines the esophagus
WHYYYY???
protective against vomit, heat, food
eating food - peristalsis, so food is pushed down and scraped against esophagus
stratified cause multiple layers - to not top open esophagus
describe structure of stratified cuboidal
two layers of cuboidal cells
describe structure of stratified columnar
surface cells are columnar
cells underneath vary in size and shape
describe location and function of stratified cuboidal or columnar
l - ducts of large glands (ducts connect gland to skin) (sweat, mammary, esophageal)
f - protection
name the 2 types of epithelium that are rare
stratified cuboidal or columnar
visually describe stratified cuboidal
2 layers of nuclei visible
visually describe stratified columnar
only apical layer columnar - named by this
describe structure function location of transitional epithelium
s - multiple layers of cells, shape depends on stretching
f - can stretch and return to original shape
l - lining urinary system organs
visually describe transitional epithelium
in its relaxed state
has connective tissue
looks like cauliflower or broccoli (scalloped)
basement membrane
what type of epithelium is found in mucosa of nasal cavity and lung bronchi and trachea
pseudo stratified ciliated columnar
what type of epithelium is found in mucosa of mouth and esophagus lining
stratified squamous
what type of epithelium is found stomach to anus
simple columnar
describe connective tissue (gen)
ECM - extracellular matrix, fibers ground tissue
cells
ex - jello with fruit pieces in it
name the 3 types of fibers in connective tissue
collagenous
elastic
reticular
describe collagenous fibers
made of collagen
don’t tear easy
describe elastic fibers
made of elastin
have rubbery quality
describe reticular fibers
composed of collagen (type 3)
very thin and branched
describe gen characteristics of connective tissues (structure, function, location)
l - everywhere
f - protective, binds tissues together, support, energy storage, transporting substances
s - cells surrounded by ecm
describe two components of ecm
1 - ground substance (liquid, jelly like or solid)
2 - fibers, form a web (collagenous, elastic, reticular)
how many types of connective tissue are there
6
list types of connective tissue from hardest to softest
bone (mineralized)
cartilage
dense connective tissue
loose connective tissue (areolar)
adipose tissue
blood (and lymph)
dense and loose - connective tissue proper (contain fibroblasts)
what is the function of bone (osseous tissue)
support and protection
describe ecm of bone
hydroxyapatite (ca5(po4)3(oh)) - calcium and phosphorus, makes bone hard
collagen fibers - make bone flexible
describe cells of bone
osteoblasts - make collagen for ecm
osteocytes - maintain bone, sit in cavities called lacunae
why are bones hard and not brittle
combo of hydroxyapatite and collagen make bone hard but not brittle
visually describe bone
osteons
lacunae (osteocytes)
central canal - blood vessels and nerves
what does compact bone tissue consist of
repeating units called osteons (concentric layers of matrix that surround a central canal containing blood vessels)
what’s the function of cartilage
strong and flexible support material
describe ecm of cartilage
chondroitin sulphate - combined with 80% water, rubbery strong matrix
collagen fibers - gives flexibility
describe cells of cartilage
chondrocytes - make collagen for ecm, sit in cavities called lacunae
where to find cartilage in body
anywhere where flexibility is needed
ribcage - sternum
name the 3 subtypes of cartilage
hyaline
elastic
fibrocartilage
describe hyaline cartilage
most abundant
rib cage
larynx
fetal skeleton
epiphyseal plates
trachea
describe elastic cartilage
ear and epiglottis
more elastic due to elastic fibers
describe fibrocartilage
absorbs shock
highly compressible
intervertebral discs
what’s the function of dense (fibrous) connective tissue
attachment (bone to bone)
strengthen skin
describe ecm of dense connective tissue
collagen fibers - closely packed to provide strength and structure
describe cells of dense connective tissue
fibroblasts - make collagen for ecm
visually describe dense connective tissue
collagen fibers
nuclei darker
kinda looks like a wave or ocean
locations of dense connective tissues
tendons
ligaments
dermis of skin
what’s the function of areolar (loose) connective tissue
packing material that glues together organs and soaks up extra fluid (edema)
explain why things swell
areolar connective tissue soaks up water/fluid
immune system tried to help (fluid)
describe ecm of areolar connective tissue
collagen fibers
elastic fibers
reticular fibers
describe cells of areolar connective tissue
fibroblasts - make collagen for ecm
macrophages - white blood cells that phagocytize dead cells and bacteria
where to find areolar connective tissue in the body
EVERYWHERE
visually describe loose connective tissue
elastic fibers look like hair
fibroblast nuclei visible
collagen fibers - darker thicker lines
describe function of adipose (fat) tissue
padding and insulating organs and fuel storage
describe ecm of adipose tissue
collagen fibers
elastic fibers
reticular fibers
describe cells of adipose tissue
adipocytes - contains a large fat droplet that swells when fat is stored and shrinks when the body uses fat or fuel
where to find adipose tissue in body
EVERYWHERE
surrounding organs
subcutaneously
abdominal fat
visually describe adipose tissue
looks like eyeballs or bubbles
fat droplets
capillary - width of single blood cell
what is the function of blood
transport of substances throughout the body
describe ecm of blood
plasma - water with dissolved salts and proteins
describe cells of blood
erythrocytes - rbc - contain hemoglobin and carry oxygen
leukocytes - wbc - function in the immune system
platelets - cell fragments - function in blood clotting
where to find blood in body
in blood vessels
everywhere
visually describe blood
white blood cells look brighter - different
red blood cells look the same - red and round ish
what is muscle tissue composed of
long cells called muscle fibers
capable of contracting (shortening) to produce movement
what do muscle cells contain
elongated contractile threads called myofibrils - made of actin and myosin
what do muscle cells account for
most of the body’s energy consumption
name the 3 types of muscle cells
skeletal (voluntary)
smooth (involuntary)
cardiac (involuntary)
describe skeletal muscle
attached to skeleton (produces body movements and face expressions)
striated, multinuclear cells with long cylindrical shape
describe cardiac muscle
forms contractile wall of heart
striated, branches, cells with single nucleus
cells connected by intercalated discs (contain gap junctions) which relay signals between cells during a heartbeat
describe smooth muscle
found in walls of hollow organs (digestive tract, urinary bladder, arteries…)
NOT STRIATED, spindle shaped cells with single nucleus
contacts more slowly than skeletal muscles - but remains contracted for longer time
describe nervous tissue
senses stimuli and transmits signals from one part of animal to another
composed of neurons and supporting cells called neuroglia
describe neurons
functional unit of nervous tissue
cell body and processes (dendrites and axons)
describe dendrites
transmit nerve impulses towards the cell body
describe axons
transmit nerve impulses away from cell body towards another neuron or an effector (muscle cell)
location of nervous tissue
brain
spinal cord
nerves
