Download cell-n-genetics-2007

Cell and genetics –histology 2007
• Cells
° Stem cells
° Cells of the 4 basic tissues
° Other specialized cells
• Jeanne Adiwinata Pawitan
Dept. of Histology FMUI
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Stem cells
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Stem cells – ability to differentiate
Totipotent = all +
placenta
Pluripotent = all
Multipotent = several
Unipotent = 1 type ><mature: self renewal
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Stem cells - source
• Embryonic stem cells (inner cell mass)
• Adult stem cells: bone marrow, umbilical
cord blood, Wharton jelly, adipose tissue, etc.
° Multipotential - > determined – adult stem cells
in 1 lineage: connective tissue, blood, etc
° Unipotential – progenitors (commited) 1 cell line
→ differentiation → precursor → mature fully
differentiated cells
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Cells of the 4 basic tissues
• Epithelium: cells, intercellular substance/extracellular
matrix – basement membrane
• *Connective tissue: intercellular substance↑
• Muscle: muscle cells* = muscle fibers
• Nerve*:
° Neurons
° Neuroglial cells (support, protect neurons)
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Epithelium
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Epithelium (and glands)
• Layers
• Shape
° Single
• Simple
• (Pseudostratified)
° Multiple
• Stratified
• (Transitional)
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° Squamous
° Cuboidal
° Columnar
(torax)
• Location
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Polarity and cell surface
specializations
• Morphological domain
• Biochemical domain
Polarity
• Functional domain
Apical domain – free surface – lumen
Basolateral domain
Basal - basal lamina
Lateral – other cells
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Apical domain - lumen
• Microvilli
• Cilia
° Kinocilia
° Stereocilia
•
•
•
•
•
•
Ion channels
Aquaporins
Carrier proteins
H+- ATPase
Glycoproteins
Hydrolytic enzymes
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Basolateral domain
• Intercellular interdigitation, basal enfoldings
• Junctional specialization
• Receptors
° Hormones
° Neurotransmitters
• Na+-K+ ATPase
• Ion channels
• Sites for constitutive secretions
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Junctional
specialization
• Lateral membrane
specialization – terminal
bars (LM) – junctional
complexes (EM)
° Occluding junction, tight
junction, zonula occludens
° Adhering junction
• Zonula adherens -zonulae
adherentes
• Fascia adherens
• Macula adherens (desmosome)
- hemidesmosome
° Gap junction
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Epithelial cells
Simple squamous
Simple cuboidal, columnar
Stratified cuboidal, columnar
Pseudostratified
Endothelium,
mesothelium
Glands
Respiratory S.
Transitional
Urinary S.
Stratified squamous – keratin +
Epidermis-skin
Stratified squamous – keratin -
Mucous
membrane: oral,
esophagus, vagina
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Connective
tissue
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Connective tissues
• Mesenchyme (embryo) – mucosa
/gelatinosa
• Connective tissue proper
°
°
°
°
Loose (areolar) connective tissue
Reticular connective tissue
Adipose tissue
Dense connective tissue
areolar CT
• Dense regular connective tissue
 Dense regular collagenous connective tissue
 Dense regular elastic connective tissue
• Dense irregular connective tissue
• Specialized connective tissue (cartilage, bone, blood)
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Intercellular substance/ extracellular
matrix
• Ground/amorphous substance (gel like)– tissue
fluid
° Glycosaminoglycans (GAG) (hyaluronic acid, heparin,
sulfated GAG)
° Proteoglycans ( certain GAG – Protein)
° Adhesive glycoproteins (fibronectin, laminin, entactin,
tenascin, chondronectin, osteonectin)
• Fibers
° Collagen type I – VII
• Reticular (type III collagen)
° Elastic fibers
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• Cells of mesenchyme
° Mesenchymal cells
• Cells of loose
connective tissue
• Cells of reticular CT
° Reticular cells
° Lymphocytes
° Plasma cells
• Cells of cartilage
• Cells of bone
• Cells of blood
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Cells of
connective tissue
Loose connectine
tissue
• Fixed cells
°
°
°
°
°
Fibroblasts/fibrocytes
Histiocytes/macrophages
Mast cells
Pericytes
Adipose cells
• Transient cells:
° plasma cells
° leucocytes
° macrophages
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Cells of cartilage
Chondrogenic cells
Chondroblast
Chondrocyte
Shrunken
lacuna
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Osteogenic cells
Osteoblast
Osteocyte
Osteoclast
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Cells of bone
Cells of blood
Erythrocyte
Leucocyte
Neutrophil
Eosinophil
Basophil
Monocyte
lymphocyte
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Basement membrane
• Basal lamina
° Lamina lucida
° Lamina densa
• Lamina reticularis:
type I, III collagen
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Muscles
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Muscles
• Striated muscle – characteristic striation –
specific arrangement of myofilament (contractile
protein in a myofibril: myosin, actin)
 parallel arrays
 interdigitating
° skeletal muscle
° cardiac muscle
regularly repeated arrangement
in myofibril
• Smooth muscle
Myoepithelial cells –glandular unit in glands
Myofibroblast – wound contraction, tooth
eruption
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Unique terms in muscle
• Sarcolemma = cell membrane
• Sarcoplasm = cytoplasm
• Sarcoplasmic reticulum = smooth
surfaced endoplasmic reticulum (SER)
• Sarcosome = mitochondria
• muscle fiber = muscle cell
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Smooth muscle
• Location: wall of hollow organ - lumen
°
°
°
°
°
°
Digestive system
Reproductive system
Urinary system
Respiratory system
Ducts - large (glands)
Dermis (skin)
• Function:
° contraction
° Protein synthesis  extra cell: collagen, elastin,
glycosaminoglycans, proteoglycans, growth factors
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Smooth muscle
• contraction - involuntary – controlled by
° Autonomic nervous system (sympathetics,
parasympathetics)
° Hormone: bradykinin
° Local physiological condition
• Every fiber – lined by external lamina (outside
sarcolemma)
° reticular fiber - embedded in external lamina –
surrounding each muscle cell – function: control and
unify the strength of muscle fiber contraction
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• Shape : fusiform, elongated
–Ø 5-6 μm, length -0.2 mm
• Surrounded by sarcolemma
(cell membrane)
• Nucleus - center – oval – 1-2
nucleolei – at contraction 
nucleus  bottle opener
• HE: cytoplasm –
homogenous – acidophilic
• Iron hematoxylin – in
sarcoplasm:
° Dense body – attached at the
inside of cell membrane
° Longitudinal lines  groups of
myofilaments
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Smooth muscle
fiber
Smooth muscle fiber
• Form sheets/layers – usually 2 layers –
perpendicular
• fibers –closely packed – thin part ><
thick part
° Cross section – fiber diameter ≠ – section nucleus (+)/(-)
• Individual cell
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Innervation – smooth muscle fiber
• Neuromuscular junction usually en passant type
° Bulging of axon
° Containing synaptic vesicles
• Nor epinephrine – sympathetic
• Acetylcholine – parasympathetic
• Type
° multi unit –individual innervation (iris, vas deferens
° Intermediate (mixed 30-60% - individual)
° Visceral – some fibers – 1 neuromuscular junction – gap
junction/nexus (uterus, GI tract) – other influencing
factor
• Humoral factor : oxytocin
• Micro environmental factor : stretching (intestines)
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Cardiac muscle
• Development: Myoepicardial mantle in
splanchnic mesenchyme  epicardium +
myocardium
• Cardiac muscle
° Cardiac muscle fiber–branching-anastomosing
network – arranged in layers (laminae)
° Between fibers – connective tissue
° Connective tissue between laminae – contains:
• Blood vessels  capillaries  network –in connective tissue
between each fiber
• Nerves
• conducting system – in heart
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Cardiac muscle
fiber
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• Striated, branching
• Length 15-80 μm
• Nucleus 1 (occasionally 2) –
center – big –oval
• Perinuclear space
• Between cells (at the end) intercalated disk -consist of:
° Transverse portion: facia
adherens ( Z disk),
desmosome
° Lateral portion: gap
junction (also found in
regions - side by side
contact – long.)
Sarcoplasm contains
• Myofibrils Ø-1-2 μm –longitudinal –regularly
arranged  striated (longitudinal section):
° A band – (anisotropic on polarized light  dark)
° I band– (isotropic on polarized  light)
• EM: Sarcoplasmic reticulum = SER
°
°
°
°
°
Network around myofibril
Function: intracellular Ca storage (< skeletal muscle)
Small terminals (terminal cisternae -)
The rest = longitudinal sarcotubule + branches
Contraction needs active transport of Ca from extra cell
• membrane contains junctional feet (= voltage gated Ca release
channels)
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Sarcoplasm contains
• Organels
° Mitochondria >>> - ½ volume – cardiac
muscle
° Myoglobin  O2 transport
° Glycogen particle  energy source for
contraction ( with lipid)
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Cardiac muscle fiber – T tubule
• EM: Sarcolemma – tubular invagination –
transverse – branching - anastomosing T tubule
(transverse tubule)
• Intertwine among myofibril
• Location: around Z line – 1/sarcomere
° Open to extra cellular compartment -lined by external
lamina
° Ø 2.5 X T tubule in skeletal muscle
• Function: facilitate conduction – depol. wave -along
sarcolemma
• Associated with sarcoplasmic reticulum: T tubule +
small terminals  dyad
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Myofibrils
• A band (dark) – H band (light) – M line
• I band (light) – Z line (Z disk, dark)
• Sarcomere = myofibril region between 2
Z line = 1 contractile unit
• Contraction:
°
°
°
°
I band - shortened
H band - disappeared
A band - constant
Z line - approaching each other
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Cardiac muscle fiber-atrium
• Ø < fiber in ventricle  myoendocrine cells
• Contains granules - cardiodilatin (CDD)/Atrial
Natriuretic (Poly)peptide (ANP) – esp. in right
atrium
° ANP – regulation of fluid –electrolyte balance
• Efferent arteriole constriction  diuresis, sodium excretion↑
• Sodium, water resorption in kidneys (renal tubules)↓  blood
pressure ↓ • Vasodilatation
• inhibit the release of arginine-vasopressin (posterior
hypophysis), and aldosterone (adrenal cortex)
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Skeletal muscle
• investments
° Epimysium – muscle – irregular dense
collagenous connective tissue
° Perimysium – fascicles (bundles) - < dense
° Endomysium – muscle fiber (cell) - reticular
fiber, basal lamina / external lamina
• cell
° Skeletal muscle fibers – striated – parallel
° Satellite cells
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• Development: myoblast – parallel
 end –end  fused  myotube
– formed myofibril  skeletal
muscle fiber
• Shape: long, tubular – Ø 10100μm
• Between fibers: endomysium +
continuous capillaries – parallel to
fiber
• Skeletal muscle fiber – non
branching -striated multinucleated
• Nuclei – periphery – in a row –
inside cell membrane
(sarcolemma)
• EM: Sarcolemma invaginate T
tubule (transverse tubule)
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Skeletal muscle
cells/fibers
Sarcoplasm: contains
• A lot of myofibril Ø-1-2 μm –longitudinal – along
the fiber – regularly arranged  striation in
longitudinal section:
° A band – (anisotropic on polarized light  dark)
° I band– (isotropic on polarized light  light)
• EM: Sarcoplasmic reticulum = smooth surface
endoplasmic reticulum
° Form a network around myofibril
° Function: intracellular Ca storage (esc. terminal cysterna)
° A-I junction – dilated  terminal cysterna
• The membrane has junctional feet (= voltage gated Ca release
channels)
° The rest = longitudinal sarcotubules + their branches
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T tubule
• Tubular invagination –transversal – branchinganastomosing – intertwine among myofibril
• Location: transversal plane - A-I junction  2 in
each sarcomere
• To extra cell - open
• Associated with sarcoplasmic reticulum
• Function: facilitate conduction of depol wave
along sarcolemma
• T tubule + 2 terminal cysternae  triad
° function: spreading of depol wave – fast – from
sarcolemma – trough out the cell – to terminal cysterna
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Myofibril
• A band (dark) – H band – pale –M line
• I band (light) –Z line, Z disk – thin, dark
• Sarcomere = myofibril area between 2 Z line =
contractile unit of skeletal muscle fiber
• Contraction:
°
°
°
°
I band shortened
H band disappeared
A band remain unaltered
Z line – move closer together
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Satellite cells
• Satellite cells = regenerative cells
• Small cell – location: shallow depression
– muscle cell’s surface
• External lamina – shared with muscle cell
→ inside external lamina
• Nucleus-one - > dense - > coarse
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Myotendinuous junction
• Connective tissue–muscle – tendon –
continuous
° Cells tapered – fluted (deeply folded)
° Collagen fibers-tendon – penetrate
• Infoldings
• Endomysium – continuous – reticular fibers
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Innervation of skeletal muscle
• Motor nerve fibers (α motor neurons –axonmyelinated) branching – unmyelinated
(Schwann cells +) – terminal dilated myoneural junction (motor end plate)
° Axon terminal
° Synaptic cleft
° Muscle cell membrane
• Sensory nerve fibers
° muscle spindles – among muscle cells –stretch Rx
° Golgi tendon organ (neurotendinuous spindle)–
inhibitory feedback - α motor neurons - relax
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Regeneration - muscles
• Skeletal muscle – regeneration (+)
° Skeletal muscle fiber ≠ mitosis
° Satellite cells
• Injury: satellite cells - mitosis – hyperplasia
• At muscle building: satellite cell – muscle fiber fusion  mass increase  hypertrophy
• Cardiac muscle - ≠ regeneration, fibroblast
– connective tissue (scar)
• Smooth muscle – regeneration (+)
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Regeneration – smooth muscle
• Injury formation of new fibers
° Mitosis – smooth muscle fiber (GI tr., urin. tr.)
° Differentiation - pericyte – blood vessel
• Uterus –pregnant – smooth muscle
° hyperplasia - mitosis
° hypertrophy
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Nervous tissue
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Neurons
• Cell body (soma,
perikaryon) – nucleus –
nucleolus prominant
• Dendrite (multiple)
° Nissl bodies
° Branching
• Axon (single) – long branching
° Axon Hillock
° Axon terminals, end
bulbs, terminal boutons
→ synapse
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Specialized
cells
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Specialized cells
•
•
•
•
Protein secreting cells
Steroid secreting cells
Neuroendocrine cells
Cells in organs → other modules
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• Ex.: chief cells (stomach),
acinar cells (pancreas)
• Shape: columnar,
truncated pyramid, etc
• Basal cytoplasm basophilic
° Nucleus
° Rich in RER, polysome
• Apical cytoplasm acidophilic
° Secretory granules –
proenzyme (zymogen)
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Protein secreting
cells
Steroid secreting cells
• Ex: spongiocytes
(adrenal cortex)
• Shape: polyhedral
• Cytoplasm
° Extensive network of
SER
° Lipid droplets –
appear vacuolated
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• Argentaffin, argyrophilic
– silver staining
• APUD= amine precursor
uptake decarboxylation
• DNES= diffuse
neuroendocrine system
• Location:
epithelium/glands –
systems
• Secretory granules –at
basal cytoplasm/ near
blood vessel
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Neuroendocrine
cells
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