Glossary of Histology Tissues
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- Aggregate cells designed to perform one or more functions
- Epithelium Tissue
- Covers body surfaces, lines body cavities, + formas glands
Specific cell-cell adhesion (cell junctions)
Functional + morphological polarity
Attached to an underlying basement membrane
- Connective Tissue
- Extracellular matrix supports structurally + functionally
Includes bone and cartilage
- Muscle Tissue
- Functional porperties of contraction allow movement
- Nerve Tissue
- Neurons revieve, transmit, + integrate informatino to control body
- What is blood tissue?
- fluid connecticut tissue in the cardiovascular system
- How much blood is in an adult human?
- 6 Liters
- What is the function of blood?
- transport nutrients
maintain homeostasis by a buffer system
- What is hematocrit?
- percentage of formed elements in blood based upon volume
- What are the components of blood?
- What is the percentage of plasma in blood?
- 55% plasma
45? formed elements
- What is the hematocrit level for males and females?
- male 39-50%
- What are the formed elements in the blood?
- erythrocytes (red blood cells)
leukocytes (white blood cells)
- How many erythrocytes are in 1 mm3 of blood?
- 4-5 millin/mm3
- How many leukocytes are in 1 mm3 of blood?
- 6-9 million/mm3
- How many thrombocytes are in 1 mm3 of blood?
- 200,000 -400,000/mm3
- What are the components of plasma, %?
- water 91-92%
other components 1-2%
- What proteins are in plasma?
- albumin (maitain osmotic pressure)
globulin (immune system molecules)
firbinogen (fibrous net to prevent further blood loss)
- What other components, besides protein and water, can be found in the plasma?
- electrolytes (Na+, K+, Ca2+, HCO3-, etc.)
nitrogenous compound (urea, uric acid, creatine)
nutrients (glucose, AA, lipids)
gases (CO2, O2, N2)
regulatory substances (hormoes, enzymes)
- What is the structure of an erythrocyte?
- biconcave disk
7.8 um diameter
2.6 um edge
0.8 um center
- What do erythrocytes stain with?
- What is the lifespan of erythrocytes?
- 120 day lifespan
- How are old erythrocytes removed?
- 90% phagocytosed by macrophages in spleen, bone marrow, and liver
10% break down intravascualarly
- What are the integral membrane proteins of erythrocytes?
band 3 protein
- What are the peripheral membrane proteins of erythrocytes?
- actin, adducin, band 4.1, spectrin
- What is the function of membrane proteins in erythrocytes?
- network that laminates inner layer of membrane
junctional complexes stabilize prectrin tetramers
- How is blood type recognized by erythrocytes?
- sugar groups on peripheral proteins (type: A,B,O)
- What is the structure and funciton of hemoglobin?
- globulin alpha, beta, delta, and gamma
located on the large erythrocyte surface
iron-bound gas exchange
affinity for O2
- What is a leukocyte?
- digestive cell containning lysosomes
- What are granulocytes?
- leukocytes with specific granules
- What are the different types of granulocytes, %?
- neutrophils 55-60%
- What are agranulocytes?
- leukocytes that lack specific granules
- What are the different types of arganulocytes, %?
- lymphocytes 30-35%
- What is the structure of a neutrophil?
- 10-12um diameter
multilobulated nucleus (2-4)
females have 'barr body' or drum stick appendage on lobe of 1 nucleus
- What are the granules of neutrophils?
- specific granules
- What is the function of specific granules in neutrophils?
- release suring inflammatory response
- What is the function of azurophilic granules in neutrophils?
- larger, less numerous
similar to lysosomes (acid hydrolases)
defensins (form channel in bacteria wall)
contain myeloperoxidase (reactive bactericidal chlorines)
- What is the function of tertiary granules in neutrophils?
- contain enzymes secreted by cell
can insert ahesion molecules to cell membrane
- What is the function of neutrophils?
- first wave of defense, most numerous
active phagocytes at inflammatory site
- How do neutophils kill bacteria?
- migrate to site of action in connective tissue
specific and azurophilic granules fuse with phagosome membrane
- What is pus?
- dead bacteria and dead neutophils
- What is the structure of an eosinphil?
- a leukocyte
refractile crystalloid bodies
- What is the funtion of an eosinphil?
- kill larval parasites
opperate with mast cells in allergic reactions
- What is the structure of a basophil?
numerous large granules (stain with basic dyes)
- What is the funciton of a basophil?
- similar to mast cells
- What is the structure of lymphocyte?
- a leukocyte
90% are small
lymphatic immune cells
- What are the different types of lymphcytes?
- T cells (long life, cell mediated immunity)
B cells (produce circulatin antibodies)
NK cells (short life, kill certain virus infected cells)
- What is the structure of a monocyte?
- largest WBC
originate in bone marrow
indented cell nucleus is bean shaped
- What is the function of a monocyte?
- precursor of mononuclear phagocytotic cells
differentiate into macrophages, osteoclasts, etc.
- What is the structure of a thrombocyte (platelet)?
- 2-3um diameter
glycocalyx coat, receptors
microtubules (8-24), actin, myosin
fibrogren, coagulation factors
- What is the funciton of a thrombocyte?
- platelets derived from megakayoctes
survalence of blood vessels
blood clot formation
repair of injured tissue
- What are the different types of T cells?
- cytotoxic (recognize antigens)
helper (induction of immuse response)
supressor (downregulate T lymphocyte initiation)
- What is the structure of bone marrow?
- spongy bone in flat and long bones
sinusoid blood vessels covered by reticular tissue
vascualr and hemopoetic
- What is the funciton of bone marrow?
- to produce erythrocytes and thrombocytes
new blood cells penetrate endothelium to enter circulation
not active bone marrow is predominantely adipose (yellow)
- Formaiton of erythrocytes
- Formation of neutrophil
- Formaiton of eosinophil
- Formation of basophil
- Formation of platelets
- multiple endimitoses
polyploidal cell (64n)
single lbulated nucleus
divided by membrane territory
easy release to proximal sinusoid
- What is the funciton of myofilaments?
- responsible for muscle cell contraction
- What are the two types of myofilaments?
- thin filaments
- What is the structure of a thin filament?
- 6-8nm diameter
composed primarily of actin
fibrous actin (F-actin)
globular actin (G-actin)
- What is the structure of a thick filament?
- 15nm diameter
composed of myosin II
200-300 myosin II molecules in one filamen
rod shaped tail
- What is the single purpose muscle cells contain a large number of contractile filaments?
- to produce mechanical work
- What are the pincipal types of muscle?
- striated (exhibit cross-striations)
smooth (do not exhibit cross-striations)
- What are the types of muscle, based upon location?
- What is the structure of skeletal muscle?
Where can it be found?
- attach to bone
movement of axial and appendicular skeleton
maintinance of body position and posture
- Where can smooth muscle be found it be found?
- Tongue, pharynx, upper esophogas
- What is the structure of cardiac muscle?
Where can it be found?
- striated muscle
wall of the heart
base of large veins that empty into heart
- What is characteristic about skeletal muscle?
- multinucliated syncytium
- What connective tissues hold together muscle fibers?
- What is the structure and function of endomysium tissue?
- delicate layer of reticular fibers that immediately surround individual muscle fibers
- What is the structure and function of perimysium tissue?
- thicker connective tissue that surround a bundle/fascicle of fibers
- What is the structure and function of epimysium tissue?
- a sheath of dense connective tissue that surrounds a collection of fascicles
- What are the different types of skeletal muscle?
- Type I, slow oxidative fibers(red)
Type IIa, fast oxidative glycolytic fibers (white)
Type IIb, fast glycolytic fibers (intermediate)
- How are types of skeletal muscles distinguished?
- color when dyed
speed of contraction and relaxation
- What is the structure and function of Type I skeletal muscle?
- intermediate fibers contain many mitochondria and large amounts of cytochrome complexes and myoglobin
slow-twitch fatigue-resistant motor units
- What is the structure and function of Type IIa skeletal muscle?
- many mitochondria and a high myoglobin content
capable of anaerobic glycolysis
fast-twitch fatigue-resistant motor units
longer distance sprinters
- What is the structure and function of Type IIb skeletal muscle?
- large fibers will less myoglobin and fewer mitochondria
low oxidative enzymes
high anaerobic enzyme activity on high amount of glycogen
fast-twitch fatigue-prone units
short distance sprinters, weightlifters
- What is a myofibril?
- the structural and functional subunit of a muscle fiber
composed of bundles of myofilaments
- What are myofilaments?
- inficifual filamentous polumers of myosin II, actin, and associated proteins
- What are the structural levels of muscle fiber, magnification?
- skeletal muscle
- What are the different bands of a myofibril?
- A band (actin, myosin, dark)
I band (unbound actin, light)
Z line (dark border)
H band (unbound myosin, light)
M line (most central line)
- What is the basic contractile unit of striated muscle?
- What is the structure and function of a sacromere?
- segment of myofibril between adjacent Z lines
- What are the thin filament proteins?
- What are the thick filament proteins?
- myosin II
- What is the structure and function of tropomyosin?
- double helix of two polypeptides
forms filaments that run between F-actin
when resting masks the myosin binding site on the actin molecule
- What is the structure and function of trophin?
- complex of three globular subunits
binds Ca2+ (essential step in the initiation of contraction)
inhibits myosin-actin interaction
- What is the structure and function of myosin II?
- two polypeptide heavy chains (small globular projections at right angles)
four light chains
rodshapped segments overlap
- What are the names accesory porteins used in maintainning alighnment of thin and thick filaments?
- What is the structure and function of the protein titin?
- accesory protein in muscle fiber forms elastic lattice anchoring Z lines
two springlike portions
prevents excessive stretching
- What is the structure and function of the protein nebulin?
- accesory protein in muscle fiber helps anchor thin filaments to Z line
- What is the structure and function of the protein desmin?
- accesory protein in muscle fiber surrounds Z lines
stabilize cross-links between neighboring myofibrils
- What is the structure and function of the protein myomesin?
- accesory protein in muscle fiber
holds thick filaments to M line
- What is the structure and function of the protein C protein?
- accesory protein in muscle fiber
holds thick filaments to M line
- What is the structure and function of the protein dystrophin?
- accesory protein in muscle fiber
- What is the general contraciton cycle of skeletal muscle?
- binding, hydrolysis, and release of ATP
- What happens to the thin and thick filaments during contraction of a muscle?
- filaments do not shorten but increase their overlap
thin filaments slide deep past thick filaments into the A band
I bands and H bands shorten as Z disks are drawn closer
- What happens during the initiation of contraction of a muscle?
- depolarization and Ca2+ release
sarcolemma is depolarized
T tubules convey the wave of membrane depolarization to myofibrils, DHP alter conformation
Ca2+ released into cystol A-I junctions via release channels
high Ca2+ lvls continues contraction cycle
- What happens during the activation of actin in muscle fibers?
- resting state-tropomyosin covers myosin binding sites
Ca2+ binding by troponin C results in conformational chnage, breaks TnI-actin bond
tropomyosin shifts and uncovers myosin-binging site
- What happens during relaxation of a muscle?
- low Ca2+ concentration
tropomyosin returns to resting state position
Ca2+ pump in SR membrane is bound
- What is a motor unit of muscle cells?
- neuron and innervating muscles
"all of none law"
- What are the types of innervations of skeletal muscle?
- myoneural junction
muscle spindle (stretch receptor)
Golgi tendon organ
- What are the structural components of the myoneural junction?
- axon terminal lacks myelin, has Schwann cell
sarcolemmal incaginations (junctional folds)
postsynaptic membrane (acetylcholine receptors)
sarcoplasm (mitochondria, ribosomes, rER)
- What is the sarcoplastic reliculum?
- modified smooth endoplasmic reticulum
- What happens in the conduction of nerve impulse across a myoneural junction?
- presynaptic membrane is depolarized
voltafe-gates Ca2+ channels open
rise in cytosolic Ca2+ releases acetylcholine into synaptic cleft
acetylcholine binds to receptors of postsynaptic membrane results in a depolarization
degradation of acetylcholine ends the signal
recycling of acetylcholine
- What is the structure of the muscle spindle (stretch receptor)?
- fluid filled periaxial space is bound by connective tissue
contains 10 modified skeletal muscle fibers surrounded by norma skeletal muscles
- What is the funciton of the muscle spindle (stretch receptor)?
- stretching of a muscle-stretches the spindle
stimulates afferent nervve endings
response is dependent upon rate and duration or stretch
- What is the structure and function of the Golgi tendon organ in the mucles cells?
- collagen fibers sitmulated too strenuously on tendon
counteracts the effects of muscle spindles
- What are the general features of cardiac muscle cells?
- contract spontaneously
display rhythmic beat
doorly defined myofibrils
do not regenerate
- What are the structural components of cardiac muscle cells?
- T tubules are larger that skeletal muscle, lined by lamina
dyads-contain T tubule and SR
connective tissue elements
- How do calcium ions act in cardia muscle cells?
- Ca2+ leaks into carcoplams at slow rate during relaxation (autonomic rhythm)
Ca2+ released from SR in response
contraction is dependent on concentratio of Ca2+
- What are intercalated disks in muscle cells?
- comples step-like junctions between adjacent cardiac muscle cells
- What are Purkinje fibers?
- modified cardiac muscle cells in bundle of His
conduction with a few myofibrils
- What is the structure of smooth muscle?
- nonstriated, fusiform cells
central nucleus (corkscrew shape when contracted)
mitochondris, RER, and Golgi concentrated at poles of nucleus
sarcolemmal vesicles (Ca2+ movement)
nexus gap junctions
- What is the difference between skeletal and smooth muscle thick filaments?
- skeletal-myosin molecules are opposite
smooth-myosin molecules all point in same direction
- What happens in the contraction of smooth muscle?
- slower and longer contraction
transient increase in Ca2+
inhibitory effect is eliminated in the presence of Ca2+
- What happens in the initial contraction of smooth muscle?
- vascular smooth muscle triggered by nerve impulse
visceral smooth muscle is triggered by stretching of muscle and spreading of signal
- What nerves innervate the smooth muscle?
- sympathetic and parasympathetic nerves
- What are some contractile nonmuscle cells?
- moyepithelial cells
- What is the general stuctrue of connective tissue?
- tissue primarily of extracellular matrix (ground substance, fibers, fluid)
- What is the general function of connective tissue?
medium for exchange
- What are the most common collagen types in connective tissue proper? What are they composed of?
- type I
- What are the different cell types associated with connective tissue? (resident/transient)?
- fibroblasts (resident)
adipose tissue (resident)
mast cells (resident)
lypmhoid cells (transient)
plasma cells (transient)
- What are the two different types of fibroblasts?
- active fibroblasts
- From where are fibroblasts formed?
- asire from mesenchymal cells
- What is the structure of a fibroblast?
- within connective tissue proper
two or more nuclei
- What is the structure and funtion of active fibroblasts?
- spindle-shaped (fusiform)
well developed rER and Gogli
produce procollagen and other extracellular components
- What is the structure and function of Quiescent fibroblasts?
- small flattened cells
(except during wound healing)
- From where are pericytes formed?
- arise from embryonic mesenchymal cells
- What is the structure of a pericyte?
- small characterists of smooth muscle and endothelial cells
smaller than fibroblasts
located along capillaries with basil lamina
- What is the function of a pericyte?
- function as contractile cells that modify cappilary blood flow
differentiate into smooth muscle cells and endothelial during wound healing
- From where are adipose cells formed?
- arise from mesenchymal cells and fibroblasts
- What is the function of an adipose cell?
- synthesis, storage, and release of fat
- What are the types of adipose tissue?
- What is the structure and function of a unilocular adipose cell?
- contain a single fat droplet
receptors for insulin and other hormones
control uptake and release of free fatty acids and triglycerides
- What is the structure of multilocular adipose cells?
- contain many small fat droplets
central spherical nucleus
- What are mast cells formed from?
- arise from myeloid stem cells during hemopiesis
- What is the structure of a mast cell?
- largest cell of connective tissue proper
central spherical nucleus
well developed Golgi
- What is the function of a mast cell?
- contain secondary and primary mediators
mediate immediate hypersensitivity (allergic reactions)
degranulation occurs from second exposure and binding of IgE
- What are macrophages formed from?
- originate in bone marrow as monocytes
- What is the principle function of macrophages?
- phagocytosing cells
remove large particulate matter
assist in immune resopnse
- What is the structure of a macrophage?
- eccentric kidney-shape mucleus
vacuoles, lysosomes, residual bodies
- What are lymphoid cells formed from?
- arise from lymphoid stem cells during hemopoiesis
- What are the different types of lymphoid cells?
- T cells (cell mediated immune respone)
B cells (differentiate to plasma cells, body/humoral immune response)
NK cells (cytotoxic activity on tumor cells)
- What are plasma cells formed from?
- arise from activated B lymphocytes
- What is the structure of a plasma cell?
- clumps of heterochromatin in wheel spoke form
- What is the function of a plasma cell?
- humoral immunity
anti-body manufacturing cells
- What are the classifications of connective tissue?
- What are the types of embryonic connective tissue?
- muscous tissue (loose connective umbilical cord)
mesenchymal tissue (only in embryo, smorphous matrix)
- What are the types of connective tissue proper?
- loose conenective tissue (vascularized, flexible, fewer fibers, more abundant)
Dense connective tissue (irregular-dermis, organs; regular-tendons, ligaments)
- What is the general structure of the extracellular matrix?
- organized meshwork of macromolecules
- What are the different proteins in the ground substance?
- GAGs (glycosaminoglycans)
- What is the structure of GAG proteins?
repeating disaccharide with one amino sugar
sulfated strong=negative charge
- What are the types of GAG proteins?
- hyaluronic acid (connective tissues, not sulfated)
chondoitin sulfate, dermatin sulfate (bone, cartilage; skin)
heparin, heparan sulfate (lungs)
keratan sulfate (nucleus pulposus)
- What is the structure and function of proteroglycans?
- core protein of GASs
binding sites for growth factors and signaling molecules
- What are the different glycoproteins?
- fibronectin (cell adhesion molecule)
laminin (basal laminae anchor)
- What are the different types of extracellular fibers?
- What are the steps in intracellular collagen synthesis?
- preprocollagen synthesis (mRNA)
attachement of sugars (glycosylation in rER)
procollagen formation (triple-helix, rER)
addition of carbohydrates (Golgi)
secretion of procollagen
- What are the steps in extracellular collagen synthesis?
- clevage of procollagen ends
covalent bond (cross-link)
- What are the most common collagen fiber types?
- What is the formation, location, and funciton of type I collagen?
- fibroblast, osteoblast, odontoblast
dermin of skin, bone, tendon, ligaments, fibrocartilage
- What is the formation, location, and funciton of type II collagen?
resists intemittent pressure
- What is the formation, location, and funciton of type III collagen?
- fibroblast, schwann cell, hepatocyte, reticular cell
structural framework in expandable organs
- What is the formation, location, and funciton of type IV collagen?
- endothelial, epithelial
support and filtration
scaffold for cell migration
- What is the formation, location, and funciton of type V collagen?
- mesenchymal cell
- What is the formation, location, and funciton of type VII collagen?
secures lamina densa
- What are the components of elastic fiber?
- What is the structure of elastic fibers?
- amorphous structural proteins
elasticity to matrix
composed of elastin and fibrillin
- What are the structural divisions of nervous tissue?
- central nerous sysytem (brain, spinal cord)
peripheral nervous system (nerves, ganglia)
- What are the funcitonal divisions of nervous tissue?
motor (somatic, autonomic)
- What types of cells are containned within nervous tissue?
- neurons (conduct immpulases)
- What is the histogenesis of the nervous system?
neural plate thickens and differentiates
nerual tube (spinal cord, brain)
neural crest cells stem
- What are the different morphological classificaitons of neurons?
- unipolar (single process)
pseudounipolar (single branching process)
bipolar (single axon, dendrite)
multipolar (most common)
- What are the functional classifications of nerurons?
- sensory (to CNS)
motor (from CNS)
- What is the structure of the neruron?
- cell body
dendrites (recieve stimuli)
axons (transmit away)
- What are the characteristic components of neuronal cell bodies?
- large central nucleus
nissl bodies (clumps of polysomes, rER)
Gogli close to nucleus
neurofilaments, microtubules, microfilments
- What is the strucutre and funciton of dentrites?
- arborized terminals
spines increase area
recieve stimuli, transmit to soma
- What is the structure and function of axons?
- contain collaterals (perpendicular branches)
can be long processes (100cm)
- What are the functions of neuroglial cells?
- support and protect neurons
- What are the different types of neuroglial cells?
ependymal cells (epithelial cells)
- What is the structure and function or astrocytes?
- neuroglial cell that passess pedicles
protoplasmic (gray matter)
fibrous (white matter)
- What is the structure and function of oligodendrdrocytes?
- live symbiotically with neurons
gray and white matter
- What is the structure and function of Schwann cells?
- few mitochondria
create myelin sheath around an axon
- What are nerve synapses?
- functional appositions for transmitting signals
- What are the different classifications of synapses?
- What are the different methods of synapse signal transmission?
- chemical synapses
- What are the characteristcs of chemical synapses?
- most common neruon-neruon synapse
only neruon muscle synapse
contain neurotransmitters (acetylchoiline)
- What are the characteristics of electrical synapses?
- movement of ions between neurons via gap junctions
- What are neurotransmitters?
- diffusing chemical substances in synapse
produced, stored, and released by presynaptic neurons
- What is the structure of a synapse?
- acon terminals
preynaptic membrane (voltage-gated Ca2+)
postsynaptic membrane (receptors)
synaptic cleft (20-30nm wide space)
synaptic vesicles (transport neurotransmitters to membranes)
- What are the types of nerve fibers?
- myelin sheath
nodes of ranvier
- What is the structure and function of the myelin sheath fibers?
- produced by oligodendrocytes and Schwann cells
spiral layers of plasma membrane
present in lenght of axon
- What are the nodes of ranvier?
- regions along axons that lack myelin
discontinuities between adjacent Schwann cells
- What are the connective tissues that surrond nerves?
- epineurium (external coat)
perineurium (surrond bundle/fascicle, tight junctions)
endoneurium (thing reticular fibers)
- What are ganglia, types?
- aggregations of neruonal cell bodies
autonomic ganglia (motor)
craniospinal ganglia (sensory, dorsal root, pseudounipolar)
- What is the distophysiology of nervous tissue?
- resting membrane potential
- What are the characteristics of resting membrane potential in neurons?
- exists across plasma membrane
maintained by K+ leak channels and Na+-K+ pump
no net movement of K+ ions
- How is the action portential in neurons generated?
- stimulus creates depolarization
threshold reached-voltage gated Na+ channels allow Na+ to enter cell
reversal of resting potential
voltage-gated K+ channels triggered by depolarization to repolarize (open longer)
- How is the action potential in neurons propogated?
- longitudial diffusion of Na+ ions depolarizes adjacent membranes
most rapid in myeliniated fibers
- What are the two types of axonal transports?
- anteroretrograde transport (away from soma)
retrograde transport (toward soma for recycling)
- What is the structe and function of the somatic nervous system?
- contains sensory fibers
innervate skeletal muscle
propogate voluntary movement
- What is the structure and function of the autonomic nerous system?
- regulate smooth muscle, cardiac muscle, and glands
sympathetic and parasympathetic systems function antagonistically
- What are the types of autonomic nerves?
- pregangionic fibers to autonomic ganglion of CNS
postganglionic fibers to effector organ
- What is the function of the sympathetic system?
increase HR, BP, and respiration
- What is the funciton of the parasympathetic system?
decreases HR, BP, and respiration
- What is the structure of the CNS?
- white matter (myelinated nerve fibers, neuroglial cells)
gray matter (unmelinated neuronal bodies)
- What is the structure of gray matter in the spinal cord?
- appears in the shape of a central 'H'
dorsal horns (sensory)
ventral horns (motor, multipolar)
- What is the structure of the gray matter in the brain?
- peripheral (cortex)
purkinjie cell layer
excitatrory and inhibitory impulasis
basal ganglia in cerebrum
- What are the meninges?
- membranous coverings of the brain and spinal cord in the CNS
(dura mater, arachnoid mater, pia mater)
- What is the structure and function of the cerebrospinal fluid?
- choroid plesus
water, ions, protein
nouraishes brain and spinal cord
- What is characteristic about nerve tissue's degeneration and regeneration?
- neurons of CNS cannot divide
regeneration or proximal axonal segment
- What are the classifications of epithelia based upon?
- number of cell layers
shaper of superficial layer
- What is the shape and location of simple squamous cells?
- flattened, single layer
lining of blood vessels (endothelium, mesothelium)
- What is the shape and location of simple cuboidal cells?
- cuboidal, single layer
lining of kidney, ovary, ducts
- What is the shape and location of simple comlumnar cells?
- columnar, single layer
lining of intestine, stomach, excretory glands
- What is the shape and location of pseudostratified cells?
- falsely stratified, single basal layer (all attached to basal lamina, not all reach lumen)
lining of trachea, bronchi, nasal cavity
- What is the shape and location of stratified squamous cells (nonkeratinized)?
- flattened, multiple layers
lining of esophagus, vagina, mouth
- What is the shape and location of stratified squamous (kerateinized)?
- flattened (no nuclei), multiple layers
epidermis of skin
- What is the shape and location of stratified cuboidal cells?
- cuboidal, multiple layers
lining of ducts in sweat glands
- What is the shape and location of stratified columnar cells?
- columnar, multiple layers
lining of large excretory ducts
- What is the shape and location of transitional cells?
- dome-shaped to flattened
lining of urinary passages
- What are the functions of epithelial cells?
- transcellular transport (diffusion of gases, carrier protein and vesicle mediated transport)
- What are the different types of lateral and basal junctions? (from apex to base)
- tight junctions
- What is the structure and function of tight junctions?
- zonula occludens
surrounds apical perimeter
fusion of outer leaflets
integral membrane proteins
- What is the structure and function of intermediate junctions?
- zonula adherens
surround the entire perimeter
ribbon adhesion zone
- What is the structure and function of desomsomes?
- macula aherens
dense plaque (desmoplakins)
- What is the structure and function of gap junctions?
- communicating junctions
couple adjacent cells metabolically and electrically
ordered 12 subunits of connexons (open and closed conformation)
- What is the structure of the basal lamina?
- extracellular supportive structure
type IV collagen (some I, III), laminin, entactin, proteoglycans
- What is the structure and funciton of hemidesmosomes?
- adhesion of basal cells
dense cytoplasmic plaque
link to extracellular matrix
- What is the structure and function of basal plasma-membrane infoldings?
- ion-transporting epithlia
deep invaginations that compartmentalize
bring ion pumps close to mitochondria
- What is the structure of the apical epithelial surface?
- What is the structure and function of microvilli?
- projections of epithelia
extend into a lumen increasse SA
actin filaments with terminal web connection
brush border in kidney (proximal tube cells)
striated border of intestine (absorptive cells)
- What is the structure and function of sterocilia?
- very long mucrovilli
epididymis and vas deferend of male reproductive tract
- What is the structure and function of cilia axoneme?
- actively motile propel substances (effective and resting stroke)
9 doublets+2 configuration (ciliary dynein arms, radial spokes, central sheath, and nexin)
without central microtubules cilia would only spin
- What is the structure and function of cilia basal body?
- base of each cilium
9 triplet microtubules
- What are the classifications of multicellular exocine glands?
- duct branching (simple, compound)
shape of secretory unit (alveolar-sac/flask, tubular)
- What are the types of glands?
- exocrine (secrete into a duct or surface)
endocrine (secrete into bloodstream, no duct)
paracrine (secrete into extracellular space)
- What do multicellular exocrine glands secrete?
serous secretions (water, enzymes)
- What are the different mechanisms for multicelluar exocrine secretion?
- merocrine (parotid-releases just contents)
apocrine (marramry-part of apical cytoplasm released with contents)
holocrine (sebaceous-entire cell with contents released)
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