Histology Tissues (copy)
Terms
undefined, object
copy deck
- Tissues
- 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
transport wastes
transport gases
deliver hormones
maintain homeostasis by a buffer system - What is hematocrit?
- percentage of formed elements in blood based upon volume
- What are the components of blood?
-
erythrocytes
leukocytes
thrombcytes
plasma - 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%
female 35-45% - What are the formed elements in the blood?
-
erythrocytes (red blood cells)
leukocytes (white blood cells)
thrombocytes (platelets) - 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%
proteins 7-8%
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
elastic, deformable
7.8 um diameter
2.6 um edge
0.8 um center - What do erythrocytes stain with?
- eosin
- 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?
-
glycophorins
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
segmented nucleus
not dividing
short lives - What are the different types of granulocytes, %?
-
neutrophils 55-60%
eosinophils 2-5%
basophils 0-1% - What are agranulocytes?
-
leukocytes that lack specific granules
not segmented
actively dividing
long lives - What are the different types of arganulocytes, %?
-
lymphocytes 30-35%
monocytes 3-7% - 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
azurophilic granules
tertiary granules - What is the function of specific granules in neutrophils?
-
release suring inflammatory response
nost numerous - 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
kill bacteria - What is pus?
- dead bacteria and dead neutophils
- What is the structure of an eosinphil?
-
a leukocyte
10-12um diameter
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?
-
leukocytes
numerous large granules (stain with basic dyes)
heparin
histamine
acidic hydrolases - What is the funciton of a basophil?
-
similar to mast cells
bind antibodies
degranulate - What is the structure of lymphocyte?
-
a leukocyte
6-30um
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
disk shape
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
-
proerythroblast
basophilic erythroblast
polychromtophilic erythroblast
orthochromatophilic erythroblast
reticulocyte
erythroblast
erythrocyte - Formation of neutrophil
-
myeloblast
promyeloblast
neutrophilic myelocyte
neutrophilic metamyelocyte
neutrophil-band
neutrophil - Formaiton of eosinophil
-
myeloblast
promyeloblast
eosinophilic myelocyte
eosinophilic metamyelocyte
eosinophil - Formation of basophil
-
myeloblast
promyeloblast
basophilic myelocyte
basophilic metamyelocyte
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
thick filaments - What is the structure of a thin filament?
-
6-8nm diameter
1um long
composed primarily of actin
fibrous actin (F-actin)
globular actin (G-actin) - What is the structure of a thick filament?
-
15nm diameter
1.5um long
composed of myosin II
200-300 myosin II molecules in one filamen
rod shaped tail
projecting heads - 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?
-
skeletal
visceral
cardiac -
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
percise movement - 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
"muscle fiber"
long
cylindrical - What connective tissues hold together muscle fibers?
-
endomysium
perimysium
epimysium - 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
(marathon runners) - 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
muscle fascicle
muscle fiber
myofibril - 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?
- sacromere
- What is the structure and function of a sacromere?
-
segment of myofibril between adjacent Z lines
resting 2-3um
stretched 4um
contracted 1um - What are the thin filament proteins?
-
F-actin
tropoyosin
tropnin - 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?
-
titin
nebulin
desmin
dyomesin
C protein
dystrophin - What is the structure and function of the protein titin?
-
accesory protein in muscle fiber forms elastic lattice anchoring Z lines
two springlike portions
help stabalize
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
myosin-binding protein
holds thick filaments to M line - What is the structure and function of the protein C protein?
-
accesory protein in muscle fiber
myosin-binding protein
holds thick filaments to M line - What is the structure and function of the protein dystrophin?
-
accesory protein in muscle fiber
link laminin - 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"
unison - 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
synaptic cleft
sarcolemmal incaginations (junctional folds)
postsynaptic membrane (acetylcholine receptors)
sarcoplasm (mitochondria, ribosomes, rER) - What is the sarcoplastic reliculum?
-
modified smooth endoplasmic reticulum
surrounds myofilaments - 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
branching connections
central nuclei
glycogen granules
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
calcium ions
abundant mitochondria
atrial granules
intercalated disks
connective tissue elements
Purkinje fibers - 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
varriable lengths
regenerate
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
myofibroblasts - 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?
-
supports
medium for exchange
protects
repairs
stores fat - What are the most common collagen types in connective tissue proper? What are they composed of?
-
type I
type III
tropocollagen - What are the different cell types associated with connective tissue? (resident/transient)?
-
fibroblasts (resident)
pericytes (resident)
adipose tissue (resident)
mast cells (resident)
macrophages (transient)
lypmhoid cells (transient)
plasma cells (transient)
granulocytes (transient) - What are the two different types of fibroblasts?
-
active fibroblasts
quiescent 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
oval nucleus - 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
little rER
inactive
(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?
-
unilocular
multilocular - What is the structure and function of a unilocular adipose cell?
-
contain a single fat droplet
appear white
peripheral nucleus
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
appear brown
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
scant rER - 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
ovid cell
plae nucleus
abundant rER - What is the function of a plasma cell?
-
humoral immunity
anti-body manufacturing cells - What are the classifications of connective tissue?
-
embryonic
proper - 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
ground substance
fibers - What are the different proteins in the ground substance?
-
GAGs (glycosaminoglycans)
proteoglycans
glycoproteins
fibronectin receptors - What is the structure of GAG proteins?
-
glycosaminoglycans
repeating disaccharide with one amino sugar
sulfated strong=negative charge
large volume - 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)
entactin
tenascin
chondronectin
osteonectin - What are the different types of extracellular fibers?
-
collagen
elastic fibers - What are the steps in intracellular collagen synthesis?
-
preprocollagen synthesis (mRNA)
hydroxylation (rER)
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
self-assembly
covalent bond (cross-link) - What are the most common collagen fiber types?
-
I
II
III
IV
V
VII - What is the formation, location, and funciton of type I collagen?
-
fibroblast, osteoblast, odontoblast
dermin of skin, bone, tendon, ligaments, fibrocartilage
resists tension - What is the formation, location, and funciton of type II collagen?
-
chondroblasts
hyaline cartilage
resists intemittent pressure - What is the formation, location, and funciton of type III collagen?
-
fibroblast, schwann cell, hepatocyte, reticular cell
visceral organs
structural framework in expandable organs - What is the formation, location, and funciton of type IV collagen?
-
endothelial, epithelial
basal lamina
support and filtration
muscle, schwann
external lamina
scaffold for cell migration - What is the formation, location, and funciton of type V collagen?
-
mesenchymal cell
placenta
unknown - What is the formation, location, and funciton of type VII collagen?
-
keratinocyte
dermal-epidermal junction
secures lamina densa - What are the components of elastic fiber?
-
elastin
fibrillin - 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?
-
sensory
motor (somatic, autonomic) - What types of cells are containned within nervous tissue?
-
neurons (conduct immpulases)
neruroglial (support) - What is the histogenesis of the nervous system?
-
neruoepithelium
neural plate thickens and differentiates
nerual groove
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)
interneurons (connect)
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
scattered mitochondria
neurofilaments, microtubules, microfilments
granules - What is the strucutre and funciton of dentrites?
-
arborized terminals
lack Golgi
abundant mitochondria
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?
-
astrocytes
oligodendrocytes
schwann cells
microglia (phagocytic)
ependymal cells (epithelial cells) - What is the structure and function or astrocytes?
-
neuroglial cell that passess pedicles
protoplasmic (gray matter)
fibrous (white matter)
sealed barried
structural support
scar tissue - What is the structure and function of oligodendrdrocytes?
-
live symbiotically with neurons
gray and white matter
produce myelin - 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?
-
axodendritic
axosomatic
axoaxonic
sendrodendritic - What are the different methods of synapse signal transmission?
-
chemical synapses
electrical synapses - What are the characteristcs of chemical synapses?
-
most common neruon-neruon synapse
only neruon muscle synapse
slight delay
contain neurotransmitters (acetylchoiline) - What are the characteristics of electrical synapses?
-
movement of ions between neurons via gap junctions
almost instantaneous - 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
internodes - 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
action potential
axonal transport - 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
maintain homeostasis
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?
-
vasoconstriction
increase HR, BP, and respiration - What is the funciton of the parasympathetic system?
-
secretomotor
decreases HR, BP, and respiration - What is the structure of the CNS?
-
white matter (myelinated nerve fibers, neuroglial cells)
gray matter (unmelinated neuronal bodies)
meninges
cerebrospinal fluid - What is the structure of gray matter in the spinal cord?
-
appears in the shape of a central 'H'
central canal
dorsal horns (sensory)
ventral horns (motor, multipolar) - What is the structure of the gray matter in the brain?
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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?
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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)
absorption
secretion
selective permeability
protection - What are the different types of lateral and basal junctions? (from apex to base)
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tight junctions
intermediate junctions
desmosomes
gap junctions
hemidesmosomes - 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
actin filaments
E-cadherin
ribbon adhesion zone - What is the structure and function of desomsomes?
-
macula aherens
dense plaque (desmoplakins)
keratin filaments
glycoproteins - 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
lamina lucida
lamina densa - 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
increase SA
bring ion pumps close to mitochondria - What is the structure of the apical epithelial surface?
-
microvilli
seriocilia
cilia - What is the structure and function of microvilli?
-
projections of epithelia
nine triplets
extend into a lumen increasse SA
glycocalyx
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)
longitudinal microtubules
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+0) configuration
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?
-
mucus
serous secretions (water, enzymes)
mixed secretions - 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)