tissue A&P Flashcards
histology
study of plant/animal tissue
how many types of cells
200 types
trillions of cells
tissue is a group of ____ with similar ____ and shared ____
group of cells with similar origin and shared function
4 main tissue types
nervous
muscle
epithelial
connective
origin of tissue types
from GERM LAYERS
during EMBRYONIC DEVELOPMENT
3 germ layers
ectoderm (outer)
mesoderm (middle)
endoderm (iner)
ectoderm becomes
nervous system
integumentary system
mesoderm becomes
bone
muscle
connective tissue (includes bone)
some organs (including kidneys and reproductive organs)
endoderm becomes
lining of digestive system
lining of respiratory system
urethra
some organs (including liver/pancreas/bladder)
Cell junctions (5 types)
tight junctions (occluding “)
adherens junctions (adhesion belts)
desmosomes
hemidesmosomes
gap junctions
cell junctions function
join cells to form tissue
4 specific functions of cell junctions
1) link cells in tissues
2) tissue homeostasis
3) tissue barrier
4) cell proliferation (division)
1) Tight Junctions
transmembrane proteins
interlock plasma membranes
NO WATER PASS (leak-proof)
separate BASOLATERAL (cell?) surfaces from LUMEN
where are tight junctions
STOMACH
BLADDER
INTESTINAL TRACT (isolate basolateral from lumen)
(Leak proof)
2) Adherens junctions (Adhesion belts)
contain protein called PLAQUE (Actin filaments)
microfilaments (Actin) form “Plaque”
=== THE BELT
BELTS then connected via CADHERIN
= transmembrane GLYCOprotein
“plaque” (adherens junctions)
made of ACTIN filaments
INSIDE of cell membrane
Cadherin is transmembrane ____-protein
glycoprotein
cadherin attach to adjacent ____
cadherins
each connected to ACTIN filaments of PLAQUE (adhesion belt)
function of adherens junctions (adhesion belts)
prevent separation of EPITHELIAL surfaces
esp during contractile activities
e.g. peristalsis
why “belts” ?
encircle cell
3) desmosomes
also via PLAQUE
supported via INTERMEDIATE FILAMENTS
Intermediate filaments via KERATIN
like “buttons” at specific spots
also via CADHERINS
intermediate filaments via
KERATIN
where are desmosomes found
epidermis
cardiac muscle cells
4) Hemidesmosomes
cell to BASEMENT MEMBRANE
structure similar to desmosome
via INTEGRIN (instead of Cadherin)
Integrins attach to laminins
INTEGRIN = ____-protein
glyco-protein
transmembrane
integrin attaches to external proteins called ____
Laminins
(BASAL LAMINA)
where are hemidesmosomes found?
between the epidermis and dermis
basement membrane
epithelial cells grow on “
attaches epithelial to connective
5) Gap junctions
via CONNEXONS
connexons via CONNEXINS
intercellular transport
e.g.
ions, nutrients, waste
connexons form HYDROPHILIC channel (?)
(GAP JUNCTIONS) connexons and electric signals
conduction of electric signals
(I.e. Movement of ions)
gap junctions and heart
electrical signal spreads via gap junctions
heart muscles contract – heart beat
epithelial tissue
lines internal and external surfaces
forms secretion glands
cells arranged in layers
single or multiple layers
+ NERVE SUPPLY
- BLOOD SUPPLY (less)
epithelium function
1) PROTECT (chemical/physical)
2) ABSORB (nutrient)
3) SECRETE (hormones/enzymes)
4) EXCRETE (waste)
cell polarity & Epithelial cells
“Spatial differences in shape/structure/function”
“Epithelial cells have polarity, meaning they have distinct cell surfaces”
Superficial surface different from deep surface and from sides of cell
3 Cell surfaces
APICAL
LATERAL
BASAL
1) Apical surface
opens into body cavity/lumen
may contain cilia/microvilli
E.g.
Stomach – surface of cells that interact with food (CHYME)
2) Lateral surface
adjacent cells
cell-to-cell junctions (4)
4:
tight
adherens
desmosome
gap
3) Basal surface
opposite to apical
attach to basement membrane + Connective tissue underneath
basement membrane.
attaches epithelial to connective tissue
2 layers:
1) BASAL lamina
2) RETICULAR lamina
1) basal lamina
Collagen fibres
LAMININ (glycoprotein)
other glycoproteins
proteoglycans (note GAG)
2) reticular lamina
fibrous proteins (stronger)
via Fibroblasts
epithelium classification
1) Number of cell layers
2) Shape of individual cells
1) number of cell layers
simple epithelium
stratified
pseudostratified (ciliated or non-ciliated)
where simple epithelium?
capillaries
alveolar sacs (lungs)
why simple epithelium?
fast exchange across epithelium
where stratified?
inside mouth
pharynx
esophagus
why stratified?
strength/reinforcement
protection
when cell layer shed (“slough”)
e.g.
skin (epidermis)
where pseudostratified?
can be ciliated or non-ciliated
ciliated
= respiratory tract (mucosa)
non-ciliated
= male reproductive tract
2) shape of individual cells
squamous
cuboidal
columnar
transitional
*Squamous
flat
high rate of absorption
E.g.
Capillaries
Alveolar sacs of lungs
**Cuboidal
cube shaped
may have microvilli
Secretion and Absorption
***Columnar
may have microvilli
secretion/absorption
E.g.
Stomach
small intestine lining
**Transitional
can alter between cuboidal and squamous
“distension and stretch”
E.g.
Bladder
Ureters
Urethra (some parts)
combinations of
1) # of cell layers
and
2) shape of individual cell
Simple squamous
simple cuboidal
non-ciliated simple columnar
ciliated simple columnar
non-ciliated pseudostratified columnar
ciliated pseudostratified columnar
stratified squamous
stratified cuboidal
stratified columnar
transitional
goblet cells
simple squamous epithelium
inside of blood vessels
(ENDOTHELIUM)
inside of heart
(ENDOCARDIUM)
air sacs (alveoli) of lungs
epithelial layer of serous membranes
(MESOTHELIUM)
I.e.
of Peritoneal, Thoracic, Pericardial cavities
(PERITONEUM,
PLEURA,
PERICARDIUM)
simple squamous epithelium …
endothelium
endocardium
mesothelium
simple cuboidal epithelium
round centrally located nucleus
secretion/absorption
E.g.
surface of ovary
anterior surface of lens capsule of eye
pigmented epithelium of retina of eye
KIDNEY TUBULES
secreting portion of glands
e.g.
THYROID GLAND
non-ciliated simple columnar
see GOBLET CELLS
note also MICROVILLI
“Microvilli, finger like cytoplasmic projections, increase surface area of plasma membrane thus increasing cell’s rate of absorption.”
microvilli
surface area
non-ciliated simple columnar epithelium E.g.
stomach to anus (digestive tract)
secrete/absorb
mucus secrete (goblet cell)
LUBRICATE
digestive/respiratory/urinary/genital tracts
PROTECT
from stomach acids (gastric juices)
ciliated simple columnar epithelium
E.g.
Bronchioles
Uterine tubes
uterus
ventricles of brain
cilia
beat in unison
move mucus
move foreign particles
cough up
swallow
spit out
move oocytes (immature ova)
expelled from ovary
through uterine tubes
to uterus
non-ciliated pseudostratified columnar
NO GOBLET CELLS
No cilia
nuclei various levels
appears stratified
Absorb/secrete
non-ciliated pseudostratified columnar epithelium E.g.
epididymis
vas deferens
male urethra some parts
…
larger ducts of many glands
epididymis
narrow tightly coiled tube attached to each of the testicles
sperm cells move from testicles to epididymis
vas deferens
connects epididymis to Urethra
ciliated pseudostratified columnar epithelium
have Cilia
have GOBLET cells
goblet cells secrete mucus
ciliated pseudostratified columnar epithelium E.g.
RESPIRATORY MUCOSA
respiratory tract
cilia, mucus, foreign particles
mucus traps foreign particles
cilia sweep away mucus
stratified squamous epithelium
cells in apical layer = squamous
cells in deeper layer =
cuboidal to columnar
basal cells divide, daughter cells push upward toward apical layer
NON-KERATINIZED stratified squamous
no KERATIN
moistened by mucus
surface cells shed before die
WHERE?
wet surface lining
lining of mouth
esophagus
pharynx
vagina
WHY?
Protect (abrasion)
(water loss)
(pathogen)
KERATINIZED stratified squamous
protein KERATIN
tough
WHERE?
Epidermis
hair
nails
WHY?
Protect (abrasion)
(water loss)
(pathogen)
(UV)
Stratified cuboidal
rare epithelial tissue type
WHERE?
Ducts of sweat glands
ducts of esophageal glands
WHY?
Protect
limited secrete/absorb
Stratified columnar
UNCOMMON
basal layer shortened irregular shape
apical layer is columnar
WHERE?
some glands (esophageal)
anal mucous membrane
part of conjunctiva (eye)
WHY?
Protect
secrete
transitional epithelium
Urothelium (for urinary system)
appearance varies
relaxed
= stratified cuboidal
stretched
= stratified squamous
WHERE?
bladder
ureters
urethra
WHY?
stretch and maintain protection while holding fluids
different parts of same structures can have different epithelial tissue organization/type
goblet cells
columnar cells
secrete mucous
AKA MUCOUS CELLS
respiratory mucosa (lining of tract)
= nose, trachea, bronchi
mesothelium
simple squamous epithelium of serous membranes
serous membranes line cavities
secrete serous fluid
reduce friction
Abdominal cavity (Peritoneal)
thoracic cavity (pleural)
pericardial cavity
endothelium
simple squamous epithelium
lines inside of blood vessels
smooth surface
blood moves – no friction
endocardium
simple squamous epithelium
lines inside of heart and heart valves
smooth surface
blood moves – no friction
glands (2 types)
1) exocrine
2) endocrine
what are glands?
specialized epithelial tissue
produce/secrete substances
scattered cells or complex organs
glands release secretions into…
ducts
surface of organ/skin
bloodstream
Exocrine glands
released into duct
released onto surface of epithelium
LOCAL ACTION
endocrine
released into blood
act away from secretion site (travel via blood)
exocrine example
sudoriferous (sweat)
sebaceous (sebum) for hair
lacrimal glands (tears)
acinar cells (pancreas)
3 functional classifications of EXOCRINE
1) Merocrine
2) Apocrine
3) Holocrine
merocrine
AKA eccrine
secretions via vesicles (EXOCYTOSIS)
*most common
E.g.
Pancreas
Salivary glands
ECCRINE sweat glands
Apocrine
secretions go near apical surface
portion near apical surface is pinched off
entire apical surface is lost
substances release
E.g.
Apocrine sweat glands
mammary glands
ceruminous glands
Holocrine
secretions accumulate in entire cell
cell dies
secretions released
destroyed cells replaced via cell division
E.g.
Sebaceous glands (Sebum)
exocrine glands – structural classifications (not on exam)
shape/form
SIMPLE:
tubular
branched tubular
coiled tubular
acinar
branched acinar
COMPOUND:
tubular
acinar
tubuloacinar
endocrine glands
secrete into bloodstream
local or systemic
E.g.
Testes
ovaries
pancreas
pituitary
Connective tissue
surrounds organs/muscles
layers deep to epidermis
surface of joints
bone
blood
CT can be VASCULAR or AVASCULAR
functions of CT
structural support (bone)
Protection (bone)
Nutrition
Immune (bone marrow)
Energy storage (fat)
Transportation (blood)
CT e.g.
tendons
ligaments
cartilage
fascia
bone
blood
adipose (fat)
Blast cells
chondroblasts
= result in cartilage
osteoblasts
= result in bone
fibroblasts
= produce ECM
Cytes
mature cells
chondrocyte
osteocyte
fibrocyte
etc.
CT STRUCTURE***
basic components shared by all CT types
1) Specialized cells
2) ECM
(Via EC protein fibres, and GROUND SUBSTANCE)
ECM surrounds cells
ECM most of CT volume
CT fewer cells and more EC than EPITHELIAL
CT has fewer ____ and more ____ compared to EPITHELIAL
fewer cells, more EXTRACELLULAR material
Majority of CT volume is ____
ECM
ECM is:
1) Extracellular protein fibres
2) Fluid called GROUND SUBSTANCE
what are “Specialized Cells” of CT?
Fibroblasts
Macrophage
Mast cell
Plasma cell
Adipocyte
Leukocyte (WBC)
RBC
others
What are ECM fibre types?
Collagen
Elastin
Reticular
What are ECM GROUND SUBSTANCE components?
Water, Polysaccharide, proteins
semifluid, gelatinous, calcified, or fluid (blood plasma)
GS contains minerals in bone
one difference between Epithelial tissue and CT?
fewer cells, more ECM
ECM
Ground substance
Fibres (Collagen, elastin, reticular)
Ground substance
Consists mainly of:
water (H2O)
polysaccharides (GAGs)
proteins
It may be
fluid
semi-fluid
gelatinous
calcified
GAG types
Hyaluronic acid
Chondroitin sulfate
Dermatan sulfate
Keratan sulphate
Fibronectin (the protein)
what is GAG
long, linear polysaccharide
contain amino groups
(fibre types) Collagen fibres
via collagen proteins
stability to cartilage, tendons, ligaments
appears white
(fibre types) Elastic fibres
via ELASTIN
via FIBRILLIN
elasticity of fibres
up to 150%
(fibre types) Reticular fibres
also via COLLAGEN
thinner, more widespread
forms network
also support and strength
reticular fibres form…
STROMA (“bed/covering”) of some organs
= supportive framework of organs
E.g.
Spleen, kidney, liver
some specialized CT cells
Fibroblast
Macrophage
Plasma cell
Mast cells
Adipocytes
White blood cells(leukocytes)
RBC (?)
Fibroblast
most numerous cell
generates fibres
secrete GS (GROUND SUBSTANCE)
Macrophage
inflammatory/immune response
Phage = eat
Macro = big
Plasma cell
develops from B-Lymphocytes
IMMUNE RESPONSE
produce antibodies
Mast cell
inflammatory response
produce Histamine
Vasodilation in blood vessels
Constriction of bronchioles
Allergen = Histamines
adipocyte
fat cell
WBC (leukocyte)
allergic, inflammatory, immune
Eosinophil and Neutrophil
Eosinophil = parasitic infection
Neutrophil = infection
(More later)
CT CLASSIFICATION TYPES &&&&&&&
1) EMBRYONIC CT
a) mesenchyme
b) mucous
2) MATURE CT
a) CT propert
i) Loose CT
ii) Dense CT
b) Cartilage
i) hyaline, fibrocartilage, elastic
c) Bone
d) Fluid CT
i) Blood
ii) Lymph
Embryonic CT
from fertilization to birth
1) Mesenchyme
= Tissue that all CT comes from
= STEM CELL capabiities
2) Mucous (“Wharton’s Jelly)
= Umbilicus tissue
= muscous structure
= contains mesenchyme
= precursor STEM cells
Mature CT
postnatal to rest of life
1) CT proper
2) Cartilage
3) Bone
4) Fluid CT
1) CT proper (2 types)
a) Loose CT
= MORE CELLS
= loosely packed fibres
= high cell:ECM ratio
b) Dense CT
= LESS CELLS
= densely packed fibres
= low cell:ECM ratio
loose CT 3 types
areolar CT
adipose CT
reticular CT
1) Areolar CT
most types of connective tissue cells (even adipocytes)
most abundant CT
WHY?
strength, elasticity, support
WHERE?
around muscles
between muscle fascicles
around blood vessels
around organs
layers below the skin
2) adipose CT
of adipocytes doesn’t change – size does – as you gain weight
adipocytes mainly
WHY?
temperature
protect
energy store
WHERE?
e.g. subcutaneous tissue (subcutaneous fat)
NOTE
number of adipocytes doesn’t change – size does – as you gain weight
3) Reticular CT
reticular cells
= FIBROBLAST –> creates RETICULAR fibres
Reticular fibres = netlike
= @ stroma of internal organs
WHY?
structure support
bind together tissues
Dense CT 3 types
dense regular CT
dense irregular CT
Elastic CT
dense regular
COLLAGEN FIBRES
in “REGULAR” pattern
DENSELY packed
Parallel collagen fibres
LINEAR STRENGTH
WHERE??
TENDONS
LIGAMENTS
dense irregular CT
COLLAGEN FIBRES
IRREGULAR pattern
disorganized
STRENGTH IN DIRECTIONS (SHEARING)
WHERE???
DERMIS
HEART VALVES
sheaths
periosteum
ELASTIC CT
ELASTIC fibres
= YELLOW fibres
WHY?
stretch, elasticity
WHERE?
Large Blood vessels
lungs
2) Cartilage &&&&
Collagen & Elastin proteins
Embedded in CHONDROITIN SULFATE
high stress w/o losing shape
ONLY 1 CELL TYPE = CHONDROCYTES
Chondrocytes in LACUNAE
AVASCULAR (cartilage)
3 types of cartilage
HYALINE
= in b/w
E.g.
ribs
nose
FIBROCARTILAGE
= least flexible
E.g.
knee (menisci)
spine
ELASTIC CARTILAGE
= most flexible
E.g.
ear
hyaline
MOST COMMON
WHERE?
ribs
joints -ARTICULAR cartilage
nasal SEPTUM
trachea
WHY?
STIFF but FLEXIBLE
reduce friction
developing skeleton in fetus
ENTIRELY HYALINE CARTILAGE (in utero)
later ossified
fibrocartilage
strongest
resist compression
no bone-to-bone
limit movement
WHERE?
knee joint (menisci)
pubic symphysis
intervertebral discs
elastic cartilage
NOT SAME AS ELASTIC CT
ELASTIC FIBRES
stretchable
returns to original shape
WHERE?
EXTERNAL EAR
epiglottis
3) BONE &&&&&
bone cells
RED BONE MARROW
YELLOW BONE MARROW
minerals
somewhat flexible
4) fluid CT &&&&
i) blood
ii) lymph
watery ground substance
fluid matrix + proteins
no insoluble fibres
blood
ECM of blood = blood plasma
plasma
= water + dissolved substances
3 key elements in blood
RBC (O2 transport)
WBC
platelets (cell fragments)
lymph
fluid in lymph vessels
from interstitial fluid
LYMPHOCYTES
= T cells, B cells, immune
return to blood @ large veins near heart
WHY?
maintain solute level
blood volume
alert immune system
MUSCLE TISSUE. WHY?
movement
moves blood
moves chyme/bolus/feces/urine
generate heat (metabolism)
WHAT???
Cells with contractile proteins
muscle tissue other functions
create motion
work w/ skeletal/nervous
stabilize positions
maintain posture
storage/movement substances
E.g.
blood
food (peristalsis)
urine
etc.
GENERATE HEAT
3 types of muscle tissue
skeletal
cardiac
= within heart
= moves blood
smooth
= digestive tract
= regulate diameter of blood vessels
(E.g. Vasodilation)
skeletal muscle tissue
cylinder cell
multiple NUCLEI
STRIATED
why?
B/c CONTRACTILE proteins
VOLUNTARY
guard entrance
I.e.
urinary/digestive tract
respiratory tract
generate heat
protect organs
FASTEST***
cardiac muscle tissue
cardiocytes
SINGLE NUCLEUS (usually)
INTERCALATED DISCS (special junction)
STRIATED
INVOLUNTARY
moves blood
contributes to BP
MEDIUM SPEED
INTERCALATED DISCS junction types
DESMOSOMES
GAP JUNCTIONS
smooth muscle tissue
skin
BV
digestive
NONSTRIATED
SINGLE NUCLEUS
INVOLUNTARY
SLOWEST**
GAP JUNCTIONS***
shape difference
cylindrical
cylindrical + branched
FUSIFORM (smooth)
Nervous tissue
2 cell types:
neurons
neuroglia
neurons
conduct nerve impulse
neuroglia
non-conducting
support neurons
neurons and ACTION POTENTIALS
nerve impulses
longest cells?
neurons
up to 1 meter
parts of neuron
Dendrites (dendron)
axon
Cell body
Dendrites
receive info
axon (nerve fibre)
transmit signal
Cell body
large nucleus
other organelles
neurons and Centrioles
no centrioles for most
no cell division
neuroglia
different cell types
protect/support neurons
examples of neuroglia
Oligodendrocytes
&
Schwann Cells
help form MYELIN SHEATH
speed up rate of conduction
protect neuron axons
Membrane categories
Epithelial membranes:
= mucous
= serous
= cutaneous
Synovial membranes
what are membranes
epithelial tissue
supported by CT
AKA epithelial membranes
“Sheets of tissue that line or cover a portion of the body”
(epithelial membranes) where?
cavities:
spinal, cranial, thoracic, vertebral, oral, etc.
tracts:
GI, oral, nasal, urinary
cover organs:
kidneys, lungs, heart, liver
cover joint surface
4 categories of membranes
mucous
serous
cutaneous
synovial
mucous/serous/cutaneous = ____ membrane
epithelial membrane
mucous membranes
AKA mucosa
open to body exterior
Therefore needs mucous membrane to release mucous
= protection
E.g.
digestive, urinary, respiratory, reproductive
lubricated by mucus
mucous membrane supported by ____
AREOLAR CT
(Lamina Propria)
Lamina propria vs Basement membrane
lamina propria is below Basement membrane
lamina propria
holds nerves/BV
2) Serous membranes
AKA serosa
covers cavities that:
do not open to external env
also covers:
organs within those cavities
VIA MESOTHELIUM
+ Areolar CT
watery serous fluid
serous membrane types
Pleura
= cover thoracic cavity
= cover lungs
Pericardium
= covers pericardial cavity
= covers heart
Peritoneum
= covers abdominal cavity
= covers organs within “
2 layers of serous membrane
parietal layer
visceral layer
parietal layer lines inside of body cavity
visceral layer surrounds organ
space between is called…
a) pleural cavity
b) peritoneal cavity
c) pericardial cavity
Cavity Contains…
SEROUS FLUID
PARIETAL and VISCERAL layers are continuous
visceral and parietal MESOTHELIA
(Simple squamous epithelial membranes)
they secrete fluid
reduce friction
E.g.
b/w lungs and chest wall
3) Cutaneous membranes
Epidermis + dermis
epidermis = stratified squamous
dermis = Areolar CT + Dense irregular CT
thick, waterproof
skin random facts
15% body weight
21 sqft of skin
11 miles of Blood vessels
square inch of skin = 300 sweat glands
thickest skin = feet
thinnest skin = eyelids
skin renews every 28 days
skin colour via MELANIN
melanin protects from UV
4) synovial membranes
synovial cavity
synovial fluid
lubricate
O2 CO2 waste nutrient exchange
not true epithelium
no basement membrane
develops with CT
SYNOVIOCYTES
note cracking joints
when some joints stretched air bubbles form/release
causes cracking noise
systemic lupus erythematous (SLE)
antibodies/immune cells attack CT
ranges from mild to severe
“disease of 1000 faces” (wide ranging symptoms)
SSx (signs/symptoms)
Ulcers
arthritis
fever
fatigue
weight loss
neurological
note butterfly rash on face
Etiology
genetics
environmental
toxins
Sjogren’s syndrome
immune cells destroy EXOCRINE glands (lacrimal/salivary)
SSx
dry eyes, mouth, nose
arthritis
pancreatitis
pleuritis
more females than males
