Block 1 Exam Flashcards
Muscles are ________ cells that allows ________, __________, _________ and other propulsive movements
Muscles are contractive cells that allows locomotion, constriction, pumping and other propulsive movements
Origin of the muscle cells
mesoderm
types of muscle:
skeletal cardiac smooth
what is skeletal muscle?
Multinucleated cells with numerous nuclei peripherally located just beneath the cell membrane. responsible for voluntary movement
what is cardiac muscle?
function in propelling blood throughout the body
what is smooth muscle?
No striated.
No T tubules
Where? found in hllow viscera, GI tract, some reproductive tract, and the urinary tract. Wall of blood vessels, larger ducts of compounds glands, respiratory passages, and small bundles within the dermis of the skin. in peristalsis, blood vessel accommodation, elevation of hari follicles and lens of the eye
Function: specialized for slow, steady contraction under the influence of autonomic nerves and various hormones.
Muscle is classified according to appearance
striated muscle: skeletal and cardiac muscle smooth muscle: do not have striations
How muscle fibers/skeletal muscle develop?
multipotential myogenic stem cells—-> myoblasts —–> line up and fuse to form myotubes (multinucleated long cells) ——> after maturation is a muscle fiber (muscle cell)
Satellite cells
responsible to regenerate muscle. Typically inactuve but after ijury some become activated
Muscle fibers are arranged _______ to one another, and there long _________ and _________.
Muscle fibers are arranged parallel to one another, and there long cylindrical and striated
Identify parts of the Skeletal muscle
what is different in myosin filaments in smooth muscle fibers?
have less regular arrangement and less crossbridges
Identify the type of muscle tissue and name the parts in cross and longitudinal section
Each muscle fiber/cell is composed of a pack of __________, which are made of thousands of ________
Each muscle fiber/cell is composed of a pack of myofibril which are made of thousands of sarcomeres
the contractile unit of skeletal muscle fibers is the __________
the contractile unit of skeletal muscle fibers is the sarcomere
What we can see in muscle contraction in the sarcometer?
During muscle contraction, the various transverse bands behave characteristically.
I band becomes narrower
H band and M line are extinguished
Z disks move closer together (approaching the interface between the A and I bands)
A bands remains unaltered.
Identify parts in the TEM
TEM showing one contractile unit (sarcomere) in the long
series that comprises a myofibril. In its middle is an electrondense
A band bisected by a narrow, less dense region called
the H zone. On each side of the A band are the lighter-stained I
bands, each bisected by a dense Z disc which marks one end of
the sarcomere. Mitochondria (M), glycogen granules, and small
cisternae of SER occur around the Z disc.
Identify the parts of image, identify what tissue its
What is the sarcolema and its function?
The sarcolemma is the cell membrane of the muscle fiber and its function is to maintain a potential difference between its cytoplasmic and extracellular surfaces.
Transverse Tubules
also knows as T tubules extend into the interior of mucle cell to facilitate conduction of wave of depolarization
Sarcoplasmic reticulum
Its the sER, and its store intracellular calcium
Terminal cisternae
its a meshwork around each myofibril
What composes the triad? and its function?
tubulos T, terminal cysternae and sarcoplasmic reticulum which permits wave polarization to spread
what are costameres and where are they located?
group of proteins that works with Dystrophin-associated glycoprotein complex (DGC) to provide support and protection when contracting
Structure of myofibirls
composed of bundles of myofilaments. Actin- thin ones and myosin- thick ones.
Structure of Actin:
Its composed of F-actin, tropomyosin y troponina.
structure of myosin
its composed of myosin II
M line
consists of myomesin, C protein, cretine kinase and other proteins that interconnect think filaments to maintain the lattice arrangement.
Type I
- Slow, oxidative fibers
- adapted for slow contractions over long periods without fatigue
- many mitochondria
- many surrounding capillaries, and much
myoglobin (red fibers )
Ex. postural muscles of back
Type IIb
- Fast glycolytic fibers are specialized for rapid, shortterm
contraction
- having few mitochondria or capillaries
- depending largely on anaerobic metabolism of glucose derived from stored glycogen (white fibers) .
- Rapid contractions lead to rapid fatigue as lactic acid produced by glycolysis accumulates.
Ex. extraocular muscles
Type IIa
- Fast oxidative-glycolytic fibers
- physiological and histological features intermediate between those of the other two types.
Ex. major muscles of legs
What is cardiac muscle?
nonvoluntary striated muscle limited to the heart and proximal portions of the pulmonary veins.
Show striations due to arrangement of actin and myosin in the sarcomeres. Has intercalated discs, specialized attachment sites between adjacent cells.
Location: myocardium
Cardiac muscle differs from skeletal and smooth muscle in that it ____________ ___________ as well as the ability to _________. ________
Cardiac muscle differs from skeletal and smooth muscle in that it posseses an inherent rhythmicity as well as the ability to contract spontaneously
which type of muscle is this?
cardiac muscle
How cardiac muscle shows in sections?
Each cell has a central nuclei, large, oval although 2 nuclei are occasionally present.
What type of muscle is this?
skeletal muscle
What type of tissue is this and identify parts?
Cardiac muscle
what are intercalated discs?
Cell junctions in the Z lines.
Transverse portions: fascia adherence and desmosomes (anchoring)
Lateral portions: gap cjunctions
functional syncytium
formed by gap junctions that allow information from cell to the next, allowing muscle cell to contract in synchrony
What is the primary source of Calcium in cardiac muscle ?
Extracellular fluid
what are dyads?
Rather than triads in skeletal muscle, cardiac muscle have dyads involving terminal cisterns and T tubules
differences between cardiac muscle and skeletal muscle
- sarcoplasmic reticulum is less developed
- T tubules are wider, located in Z lines
- almost half of the volume of the cardiac muscle cell is occupied by mitochondria
sarcomere possesses the same substructure
In ________ bundles of _____ and _____ __________ crisscross the sarcoplasm obliquely
In smooth muscle cell bundles of thin and thick myofilaments crisscross the sarcoplasm obliquely
What type of muscle tissue is this one? and mention parts
smooth mucle fibers
Fibers ar fusiform elongated cells the expanded central portion contains an oval nucleus housing two or more nucleoli.
calmodulin and Ca sensitive MLCK (myosin light chain kinase)
these proteins are associated with smooth muscles to produce contraction
Smooth cell filaments:
actin is associated with caldesmon (protein blocks)
thick filaments are from myosin
microfilaments are obliquely
presence of invaginations, replace function of T tubules.
Identify cross section and longitudinal section, and type of muscle
smooth muscle fiber
Blood
se divide en erythrocitos, plasma y buffy coat
Buffy coat se compone de
leucocitos y plaquetas
tipos de leucocitos
granulocito y agranulocito
Neutrofilos
. Mas abundantes y tiene nucleos de 2-5 lobulos. En mujeres parece un muslo de pollo el nucleo.
En la sangre estan inactivos y son esferas
En el tejido son activos y son amoeboide
Granulos no especificos como myeloperoxidasa, lysozyme y defensins
Granulos especificos para degradar ECM, bactericidal proteins y new cell membrane components insertion
tipos de granulocitos
Neutrofilo
eosinophilo
basophilo
agranulocito
Lumphocitos y monocytos
Eosinophilos
se pintan rosa porque son eosinophilicos/acidos. Tiene un nucleo en dos lobulos. modula respuestas inflamatorias y remueve complejos antigeno-anticuerpo por fagocitosis. Abundante en linea del intetino y en inflamaciones cronicas.
Cuanto duran los neutrofilos ?
6-8 horas en la sangre y 1-4 dias en el tejido
Defectos en neutrofilos?
Ocasiona mas infecciones bacterianas y persistentes.
Puede tener Baja adhesion de paredes de venulas y asusencia de granulos
Basophilos
el menos de los leucocitos y el nucleo es en 2 lobulos irregulares. Basofilicos por la presencia de heparin y tienen histamina, platelet activating factor
Suplementan funcion de mast cells
anaphylaxis s
segunda vez que se expone una persona a una alergeno los basofilos degranulan rapido y causan vasodilatacion de organos y bajan la presion.
lymfocitos
El agranulo mas presente y tienen su nucleo redondo. La mayoria son: linfocitos B, CD4, CD8 y Natural Killers
Pueden ser de diferentes tamanos
pequenos: acaban de salir y tienen una cromatina bien condensada y poco citoplasma
medianos/grandes: representas linfocitos activados o NK tienen mas citoplasma mitocondria.
Linfomas
enfermedades que envuelven la proliferacion neoplastica de linfocitos o el defecto de que muestren apoptosis. Se considera maligno porque se puede esparcir
Monocito
precursor de macrofagos osteoclastos y microglia. Tienen forma de C. Todos son antigen presentinf cells y reparacion de tejido
plaquetas
tinenson bien pequenos sin nucleo y se originan de megakaruocytos. Se encargan de promover el cuagulo de sangre y reparar tears and leaks pequenos.
Normal conteo es de 150,000 a 400,000 microlitros y pueden durar hatsa 10 dias.
erytropoiesis
produccion de RBC en el red bone morrow porque necesitas mas RBC por blood loss o necesitas mas oxigeno, anemiam etc
early embrio lo hace en el yolk sac
Second trimester: lo hace en el liver, spleen
Third semester: bone marrow hasta adultos vertebra sternum and rib
Que necesitamos para que eritropoesis ocurra?
ambientes con factores especificos y factores estimuladores de colonia
Stem cells
pluripotent cell que pueden convertirse en todo y self renewal
Myeloid stem cell
celular ancestral que da granulocitos, monocitos, eritrocitos y megakaryocitos
lymphoid stem cell
celula ancestral que da limfocitos
Progenitor cells
se llaman colony forming units, hacen colonias de un solo tipo de celula.
Hay 4 linajes: eritroid, trombocito, granulocito-monocito y linfoide.
Stem cell factor
interactua con las celulas progenitoras homotopoeticas, todas
eritropoietina
factor que interactua con eitroid progenitor
trombopoietina
facto para megakaryoblasto y formacion de plaquetas
granulocyte-macrofagi-colony stimulating factor
factir para todas las celulas progenitoras mieloides
granulocyte colony stimulating factor
interactura con neutrophil precursors cells
monocyte colony stimulating factor
interactua con monocyte precursor cell
cuando tenemos el mayor potencial?
Stem cell
cuando es mayor la division mitotica?
En celulas precursoras (blasts) necesitamos mas mas mas
Cuando tenemos la mayor de caracteristicas morfologicas?
cuando la cel es madura
Cuando tenemos el mayor “self new capacity”?
stem cell
Cuando tenemos la mayor influencia de factores de crecimiento?
siempre tenemos
Bone morrow
Lo encontramos en huesos largos en hueso esponjoso
dos tipos: red y yellow (lleno de grasa)
Red bone marrow
tenemos stroma, cordones hemopoieticos o islas de celulas como osteoblastos y megacariocitos, capilares sinusoidal (importante enter circulation), macrofagos
Cuanto toma la maduracion eritropoiesis?
Una semana, 3-5 divisiones y tendra funciones especificos, nucleo se hace pequeno o se desaprece, aumento de hemoglobina y no tiene organelos.
proeritoblasto
basophilic eritoblasto
polycromatophilic eritroblasto
orthohematophilic eritroblasto
reticulocito
eritrocito
Proeritroblast
large cell con loose cromatin, nucleoli and basiphilic cytoplasm
basophilic eritroblast
La hemoglobina empieza a sintesisarse
polychromatic eritroblast
cambia el color
orthrochromatophilic erythroblast
nucleous es cuando se expulsa y empieza a hacerse un poco mas acidophilico
reticulocyto
la celula tiene poliribosomas y nos dara un network. Es un signo que estan haciendo RBC porque estan madurando
como pasa la maduracion de granulocitos?
envuelve cambios citoplasmicos, sintesis de azurofilic granules y granulos especificos.
- myeoloblast: no hay granulos
- promyelocito: golgi empieza a secretar granulos azurophilic
- myelocyte: empieza a generarse los granulos especificos aqui se define si seran eosinofilos, basofilos etc
- metamyelocito: muchos granulos especificos y el golgi se va reduciendo
- Band cell- lobular shpe of the nucleous
- mature
Despues se almacenan en el bone morrow o en la sangre para ser marginating cells (stay in place) or circulating cells. Tambien pueden ser en un tejido inflamado van a residir ahi.
como pasa la maduracion de agranulocito- monocyto?
- monoblasto: como el myoblasto
- promonocyte: grande, citoplasma basophilico y nucleo indentado
- ** se divide dos veces**
- monocytes: tienen extensive RER y large golgi
- y luego a tejidos macrophagos
T linfocytes
linfocitos que maduran en el timo
B linfocytes
maduran en el bone morrow
como se hace lamaduracion de linfocitos
- linfoblasto: celula grande y se puede dividir 2-3 veces
- linfocyto: se hacen mas pequeno
Se hacen proteinas especificas para entonces se caracterice en B or T cells
origen de paquetas
se origina porque megakaryocyte se rompe
- celula myeloid afectada por trombopoetina
- se hace el megakaryblast
- se hace grande y hace endomitosis: replicacion DNA pero no se divide y crea el megakaryocyte
- El megakaryocito tendra processes llamados proplatelets
- los proplatelets se dividen y se salen
Nissl Bodies
ribosomes scattered in the cytoplasm of the neuron. Stain dark purple
epineirum
initial segment
is where the action potential is generated
basal membrane
type 4 collagen and integrin
The blood brain barrier
Neuron classifications by structure:
unipolar:
bipolar: rare; associated with receptos for special senses, found in olfactory epithelium in the ganglia os vestibulochoclear
multipolar: ubiquitous (todos lados) are generally motorneurons, spinal cord and in the cerebral and cerebellar cortices.
Identify parts of the nervous system and the classification
Cell body
it’s the central part of the neuron which has neuron, organelles, projections called dendrites, and a long projection called axon
axon
conducting region which generates electrical signals
Neurons classifications by function
-
sensory/afferent neurons- senses to CNS
- somatic afferent -convey sensations of pain, temp, touch, preassure of the body surface
- visceral afferent- transmit pain impulses and other sensations from internal organs mucous membrans, glands and blood vessels
-
motor/efferent neurons- CNS to muscles
- somatic efferent: voluntary impulses to skeletal muscle
- visceral efferent: involuntary impulses to smooth muscle, cardial conducting cells and glands
- interneurons: located in CNS, establish networks of neuronal circuits between sensory and motoneurons and other interneurons
The sensory (afferent) component ___________ information and _________ to the CNS for processing
The sensory (afferent) component that receives information and transmits it to the CNS for processing
most unipolar
The motor (efferent) component ___________ to ________ such as muscles and cells
The motor (efferent) component transmits to effectors such as muscles and cells
mostly multipolar
The motor component divides in:
- Somatic – motor output controlled consciously or voluntarily (eg, by skeletal muscle effectors)
- Autonomic – motor output not controlled consciously (eg, by heart or gland effectors)
Fight and flight responses
- icreases heart rate
- raises clood pressure
- diverts blood flow to working muscles
- releases sugars/fats into bloodstream
- inhibits digestion
- reduces appetite
- dilates pupils
sympathetic control
What are the parts of the neurons?
The neuron structure :
- the nucleus is central y ovoid
- rER is a prominent feature
- numerous mithochondria
- neurofilaments
“Rest and digest”. Control the body’s response while at rest .
- slows down heart rate
- decreases blood preassure
- dilates blood vessels
- promotes energy storage
- stimulates digestion
- increases appetite
- constricts pupils
parasympathetic nervous system
The cells of the nervous system are derived from:
ectoderm
What are the cells of the nervous system?
neurons: responsible for the receptive, integrative, and motor functions of the nervous system
supporting cells (nueroglial cells): responsible for supporting, protecting, and assisting neurons in neural transmission
Types of support cells: Neuroglia
- astrocytes
- oligodendrocytes
- microglial cells
- ependymal cells
- schwan cells
What are neuroglia cells and their functions?
Known also as glial cells, do not participate in synaptic interactions and electical signaling. The most numerous type of cell in the brain. Lack axon and dendrites.
- Physical support and protection for neurons
- Insulation for nerve cell bodies and processes that facilitates rapid transmission
- repair neuronal injury
- regulation of the internal fluid environment
- clearance of neurotransmitters
- metabolic exchange between the vascular system and the neurons of the nervous system
Perikaryon
the cell body of a neuron
Inclusions
brown or black melanin granules in some neurons in certain regions of CNS in the sympathetic ganglia. They can be composed of lipofuscin, lipid droplets, secreting granules (signaling molecules).
_________________ and ______________ are precursos of some pigments in inclusions, are also precursos of neurotransmitter dopamine and noradrenaline
Dihydrophenylalanine and methydopa are precursos of some pigments in inclusions, are also precursos of neurotransmitter dopamine and noradrenaline
Neural cytoskeletal components
they have neurofibrils from the cytoplasm into processes. Neurofibrils are composed of:
microtubules
neurofilaments
microfilaments
microfilamento MAP-3 is present only in axon
microfilamento MAP-2 is present in cell body and dendrite
White matter
area where we have myelinated axons
gray matter
area where we have unmyelinated axons
nerve impulses will be received by _______ and they are transmitted ________ the _______.
nerve impulses will be received by dendrites and they are transmitted towards the body.
What organelle is abundant in dendrites?
mitochrondia
what is a axon and function?
Transmit the stimuli to other neurons effector cells, convey info away from cell body to another neuron or efector (muscle)
What are we seeing? What its happening?
Diagram showing a synapse releasing neurotransmitters by exocytosis from the terminal bouton. Presynaptic terminals always contain a large number of synaptic vesicles containing neurotransmitters, numerous mitochondria, and smooth ER as a source of new membrane. Some neurotransmitters are synthesized in the cell body and then transported in vesicles to the presynaptic terminal. Upon arrival of a nerve impulse, voltage-regulated Ca2+ channels permit Ca2+ entry, which triggers neurotransmitter release into the synaptic cleft. Excess membrane accumulating at the presynaptic region as a result of exocytosis is recycled by clathrinmediated endocytosis, which is not depicted here.
Classification of synapses
axodendritic: axon conecta con dendritas de otro axon
axosomatic: axon conecta con soma, cuerpo.
serial axoaxonic:
axoaxonic: Axon conecta con otro axon
Axon Hillock
site from where axon originates (el cuello). Usually lacks cytoplasmic organelles such as Nissl Bodies and golgi cisternae.
What is the initial segment?
It’s the region between the axon hillock and the myelin sheath and its where the action potential is generated
What are neuromusculat junction/motor end plate?
where neruon synapse with skeleytal muscle, the specialized synapse.
plasmalemma
the cell membrane of neurons
Peripheral nerve structure:
Smaller elements, fiber, will be covered by endoneurium, then the fascicles will be covered by perinerium, and the groups of fasciles will be covered by epinerium
Nerve impulses are conducted _________along ____________ than along _______________
Nerve impulses are conducted much faster along myelinated axons than along unmyelinated axons.
anterograde transport
transport is from the cell body to axon terminal. Its used in translocation of organelles and vesicles as well of macromolecules, such as actin, myosin, clathrin.
retrograde transport
transport is from the axon terminal to the cell body. Small molecules and proteins destined for degradation are transported to endolysosomes of th soma.
Some viruses use it to spread fro one neuron to the next and its how toxins are transported into the CNS
astrocytes
Two types: protoplasmic, in grey matter, and fibrous in white matter.
stellete shaped cells. they have many short branching processes, the foot of astrocytes form part of the blood brain barrier. Remove ions, neurotransmitter, and remnant if neuronal metabolism.
They have intermediate filaments called glial fibrillar acidic protein, GFAP, this is unique to astrocytes.
Which specilized juction facilitate transmission of impulses between presynaptic and postsynaptic neuron?
synapses
Where can happen synapses?
terminal bouton and on passage bouton
synapses can be :
chemical or electrical
blood brain barrier
group of capillaries in brain in order to protect from the entrance of molecules could damage this tissue. Epithelial cell with tight junctions resting in basal lamina, perocytes (substitue for smooth muscle for contraction) then the foot processes of the astrocytes
What are peripheral nerves?
Bundles of nerve fibers outside the CNS sorrunded by several investments of connective tissue
epineurium
Epinerium is composed of dense irregular collagenous connective tissue containing some thick elastic fibers that completely surround the nerve
perineurium
Its inner surface is lined by several layers of epithelioid cells joined to one another by zonulae occludentes (tigh juctions) and sorround by basal laminae to have the blood brain barrier
covering fascicles
endonerium
cover the nerve fibers, loose connective tissue
Peripheral neuroglia
Central Nervous System neuroglia
ALME
Astrocytes
Oligodendrocytes
Microglia
Ependymal cells
There not easy to identify in H&E
oligodendrocytes
Two types: interfasicullar o satellite
manufacturing and maintaining myelin of CNS , a single cell can provide for 50 axons.
microglial
originate in bone marrow and its part of phagocytic cell population. They clear the debris and damaged structures in CNS
ependymal cells
low columnar to cuboidal epithelial cells lining ventricles of brain and central canal of spinal cord. some have cilia to move cerebrospinal fluid
Schwann Cells
Envelop one axon per cell to provide myelin covering
function: support myelinated and unmyelinared nerve.
Peripheral Nervous system neuroglia
Nodes of ranvier
rich in votage Na ion channels
internuerons
most abundant. Impulses between sensory and efferent neruons.
What is histology?
The study of tissues of the body and how these tissues are arranged to constitute organs
WHAT IS Osmic acid, osmium tetroxide AND FOR WHAT IS USED?
ITS USED FOR LIPIDS IN GENERAL STAIN BLACK
Two Components of Tissues
Cells and Extracellular Matrix
Fixation
Small pieces of tissue are placed in solutions of chemicals that preserve by cross-linking proteins and inactivating degradative enzymes.
what are some examples of solutions for fixation?
Neutral buffered formalin and bouin fluid
Dehydration
Tissue is transferred through a series of increasingly concentrated alcohol solutions, ending in 100%, which removes all water. Removing water allows us to see
Clearing
Alcohol is removed in xylene in which both alcohol and paraffin are miscible
Infiltration
The tissue is placed in melted paraffin until it becomes completely saturated with this substance
Embedding
The paraffin-infiltrated tissue is placed in a small mold with melted paraffin and allowed to harden. If its going to be seen in EM it has to be resin instead of paraffin
Microtome
An instrument used to slice embedded tissues for light microscopy, 5-10micrometers
How dyes stain tissues?
more or less selectively behaving like acids or bases, forming puentes de sales electroestaticos.
what is the most common dye used?
Hematoxylin and eosin
How long could take a tissue prep?
It can take from 12 hrs to 2 days.
basophilic components
Cell components, such as nucleic acids, that have a net negative charge (anionic) and stain more readily with basic dyes
WHAT ELEMENTS DISPLAY BASOPHILIA? (BASIC LOVING)
HETEROCHROMATIN NUCLEI CYTOPLASMIC COMPONENTS- IONIZED PHOSPHATE IN RIBOSOMAL RNA EXTRACELLULAR MATERIALS LIKE COMPLEX CARBS
WHAT ARE Acidophilic components?
Cationic cell components, such as proteins with many ionized amino groups, that have an affinity for acidic dyes
WHAT ARE EXAMPLES OF ACIDIC COMPONENTS?
NUCLEIC ACIDS, DNA, SULFATE GROUP AND CARBOXYLIC GROUPS
Basic dyes
Tienen carga positiva por lo que se unen a cosas con carga negativa (componentes anionicos)
Ejemplos de basic dyes
Toluidine blue, alcian blue, methylene blue, hematoxylin
Acid dyes
tienen carga negativa por lo que se unen a cosas con cargas positivas Eosin, orange G, acid fuchsin
WHAT IS ACIDOPHILIA? OR EOSINOFILIA?
LIKES ACID DYE
H&E Stain
Hematoxylin stains DNA and other acidic structures dark blue or purple, and eosin stains other cytoplasmic components and collagen pink
PAS reaction
Periodic acid-Schiff reagent reacts with aldehyde residues on sugars to produce a purple or magenta color; stains polysaccharides and glycoproteins 1. GLYCOGEN 2. MUCUS 3. BASEMENT MEMBRANE 4. RETICULAR FIBERS IN CONNECTIVE TISSUE
Three lenses of a light microscope
Condenser, objective lens, eyepiece
what is the maximal resolving power of light microscopy?
0.2 micrometers. Smaller than this it cant be seen.
application of fluorescence microscopy
antibodies labed with fluorescnet compounds are important for inmunohistologic staining.
Magnification of light microscope
Objective lens x Ocular lens
Fluorescence microscopy
Tissue sections are irradiated with UV light, and they emit light in the visible portion of the spectrum
Resolving power
The smallest distance between two particles at which they can be seen as separate objects
types of light microscopy staining
- ones that differentiate between acidic and basic components of cell 2. specialized stains that differentiate fibrous components 3. metallic salts that precipitate on tissues, creating metal deposits
STAINS WITH EOSIN ELASTIN STAINS– CYTOPLASMIC STAINS– MUSCLES-
ELASTIN STAINS– GLASSY RED COLLAGEN STAINS- PINK MUSCLES- PINK
The Golgi stain is particularly good at revealing
NEURONAL FIBERS
Phase- contrast microscopy
Uses a lens system that produces visible images from transparent objects, and, importantly, can be used with living, cultured cells; based on principle of differential refractive indices darker or larger in relation to each other
Toluidine blue stain
A BASIC METACHROMATIC DYE WITH HIGH AFFINITY FOR ACIDIC TISSUE COMPONENTS
MASSON STAIN IS USED FOR…
CONNECTIVE TISSUE NUCLEI AND OTHER BASIC LIKING ARE STAINED RED
WHAT COLOR COLLAGEN STAINS WITH MASSON STAIN?
GREEN OR BLUE
DESCRIBE WRIGHT/ GIEMA STAIN
ITS USED TO IDENTIFY TYPES OF BLOOD CELLS.
WHAT COLOR ERYTHROCYTES STAIN WITH GIEMSA DYE?
PINK
WHAT COLOR PLATELETS STAINS WITH GIEMSA DYE?
LIGHT BLUE
Differential interference microscopy
Uses Nomarski optics, produces images of living cells with a more apparent 3D aspect
Confocal microscopy
Achieves high resolution and sharp focus by using a small pinpoint of high-intensity light and a plate with a pinhole aperture in front of the image detector
Polarizing microscopy
Allows the recognition of stained or unstained structures made of highly organized subunits; the oriented macromolecules rotate the axis of light between two polarizers like collagen, cellulose, actin, microtubules
Birefringence
The ability to rotate the direction of vibration of polarized light; a feature of crystalline substances or highly oriented molecules such as cellulose, collagen, micro tubules, and actin filaments
Transmission Electron Microscopy
Permits resolution around 3 nm; creates a greyscale image where the shade depends on whether electrons readily passed through the sample (brighter) or whether they were absorbed or deflected (darker). Cut with diamonds
Scanning Electron Microscopy
Provides high resolution view of the surfaces of cells, tissues, and organs; surface of specimen is dried and sprayed with very fine coating of heavy metal ( gold) that deflects the electron beam; black and white image
Autoradiography
A method of localizing newly synthesized macromolecules (DNA, RNA, protein, glycoproteins, polysaccharides) in cells or tissue sections; radiolabeled molecules react with AgBr crystals to produce dark spots in images
Enzyme Histochemistry
A method for localizing cellular structures using a specific enzymatic activity present in those structures
Phalloidin
Interacts strongly with actin
Protein A
Binds to immunoglobulin molecules and can be used to locate naturally occurring or applied antibodies bound to cell structures
Lectins
Proteins or glycoproteins that bind to carbohydrates with high affinity and specificity
Direct immunocytochemistry
Uses an antibody made against the tissue protein of interest and tagged directly with a label
Indirect immunocytochemistry
Uses a primary antibody made against the protein of interest and a labeled secondary antibody made in another species against the primary antibody
In situ hybridization (ISH)
Labeled cDNA that is complementary to a specific gene or nuclei acid sequence of interest is applied to a sample and the complementary sequences hybridize into double stranded nucleic acid
glycogen
free polysaccharide in animal cells
glycoprotein
have carbohydrate group attached to polypeptide chain. has short branched chains of sugars (oligosaccharides).
glycosaminoglycans
(GAGs) anionic unbranched long-chain polysaccharides containing aminated sugars.
proteoglycans
a compound consisting of a protein bonded to glycosaminoglycan groups, present especially in connective tissue.
enzyme digestion
pretreatment of a tissue section with an enzyme that specifically digests one substrate
counterstain
single stain that is applied separately to allow better recognition of nuclei and other structures
metal impregnation techniques
using silver slats solutions to visualize certain ECM fibers and specific cellular elements in nervous tissue
Cryofracture (freeze etching)
techniques that allow TEM study of cells without fixation or embedding.
primary cell culture
came straight from the organism
immunohistochemistry
highly specific interaction between molecules between antigen and antibodies.
What are antibodies?
An antibody, also known as an immunoglobulin, is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as bacteria and viruses
What is an antigen?
a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.
What are polyclonal antibodies?
different groups of lymphocytes in the injected animal recognize different parts of protein x and each clone produces an antibody against that part. each capable of binding a different region of protein x .
What are monoclonal antibody
Monoclonal antibodies are antibodies that are made by identical immune cells that are all clones of a unique parent cell. Monoclonal antibodies can have monovalent affinity, in that they bind to the same epitope.
what is hybridization
the specific binding between two single strands of nucleic acid, which occurs under appropriate conditions if the strands are complementary.
what are artifacts
spaces and precipitates that are not normally present in the living tissue and must be recognized
Connective tissue forms _______ ________ for the body; provides __________ ________ and its the site of exchange of waste products ,______ and ______
connective tissue forms structural support of the body and provides mechanical stability and its the site of exchange of waste products, oxigen and nutrients
___ is stored in connective tissue
Fat is stored in connective tissue
Connective tissue is composed of:
support cells and their associated matrix
Fibroblast can be ________ or _________
Fibroblast can be active or quiescent fibroblast (fibrocyte)
Mesenchymal stem cells give rise to:
Bone/osteoblasts , cartilage/chondroblasts , connective tissue and adipose tissue
The most common type of cells in connective tissue is:
fibroblast
Hematopoietic stem cell give rise to:
blood cells, monocytes (macrophages and osteoclastos), lymphocytes (plasma cell and T cell).
Conective tissue can be _____ and _____.
Conective tissue can be mature and embryonic
The 2 groups of connective tissue are:
Connective tissue proper and Spcialized connective tissue
Types of connective tissue proper : (name and describe them )
- Loose connective tissue
- dense connective tissue
- dense irregular connective tissue
- dense regular connective tissue
Adipose tissue, cartilage tissue, blood and bone are types of ________ _______ ________
Adipose tissue, cartilage tissue, blood and bone are types of specialized connective tissue
Name the support cells in the connective tissue:
- fibroblastos
- chondrocytes
- osteoblasts
- myofibroblasts
- adipocytes
What are fibroblasts ?
fixed cell in connective tissue that secrete extracellular matrix components, collagen and elastin.
origin: mesenchymal cells
What are chondrocytes?
secrete EMC of cartilage
What are osteoblast?
Secrete EMC of bone
what are myofibroblasts?
Secrete EMC and have contractile function and are enriched with a form of actin also found in smooth muscle cells.These are abundant in aras undergoing healing.
Elongated, spindly connective tissue cell.
It’s not easily stain with H&E dye by llight microscopy.
What are adipocytes?
specially adapted lipid-storing support cells that act as energy store AND cushioning and padding.
What is extracellular matrix?
consists of ground substance (gelly like), cells and fiber embbeded in it. Provides mechanical, structure support, extracellular communication, provides pathways for cell migration and modulate cell growth.
Explain ground substance components structure
As shown here schematically, connective tissue ground substance
contains a vast complex of proteoglycans linked to very
long hyaluronan molecules. Each proteoglycan monomer has
a core protein with a few or many side chains of the sulfated
glycosaminoglycans (GAGs)
What are the components of ground substance?
- proteoglycans: aggrecan, syndecan
- cell adhesion glycoproteins: fibreonectin, laminin
- glycosaminoglycans: keratan sulfate, hyaluronic acid
What are proteoglycans?
It constitute the family of macromolecules, each composed of a protein core to wich GAGs are covalently bonded
What are glycosaminoglycans- GAGs?
negatively charged long, rod- like chains of repeating disaccharides that have the capability of binding large quantities of water. Ex hyalyronic acid
Identify the image and describe
active state of fibroblast.
The active fibroblast have a basophilic cytoplasm reflectinve collagen synthesis.
Identify the image and describe
Quiescent fibroblast or fibrocytes
The fibroblast lose thei voluminous basophilic cytoplasm and the nuclei gets reduced.
hyaluronidase
Enzyme that cleaves hyaluronic acid into numerous small fragments. thus convesting the gel state of the ECM to a liquid state letting rapid spread of the bacteria through the connective tissue spaces
What are pericytes?
These cells surround endothelial cells of capillaries and small venules. Reside outside of the connective tissue because they have their own basal lamina.
Have characteristics of: endothelial cells and smooth cells (actin, myosin, and tropomyosin)
may function on contraction
What are Adipose Cells?
- Origin: undifferentiated fibroblast-like mesenchymal cells
- Function: synthesis or storage of triglycerides
- Produce hormones like Adipokines
- Types of fat cells: unilocular fat cells white adipose tissue and multilocular fat cells brown adipose tissue
what are mast cells?
Origin: bone morrow stem cells
Structure : They are ovoid and posses a centrally placed, spherical nucleus, have numerous granules in the cytoplasm.
Function: inflammatory response, innate immunity, and tissue repair. Primary mediator: histamine; Secondary: leukotrienes, thromboxanes, and prostaglandins.
What are cell adhesion glycoproteins?
Large molecules with several domains and they bind to: integrins, collagen fibrils and proteoglycans. These permit the cells to adhere to components of the ECM.
Types of glycoproteins: fibronectin, laminin, entactin, tenascin, chondronectin, and osteonectin
Decribe loose connective tissue/ aereolar tissue
What? Its characterized by abundant ground substance and extracellular fluid housing the connective tissue cells: fibroblasts, adipose cells, macrophages and mas cells (equal parts). Its very flexible and not resistant to stress
Composition? Predomina las fibras de colageno pero tiene fibras elasticas y reticulares.
Location? below mesothelial lining od body cavities, sorrounds parenchyma of glands.
** this is where the body first attack antigens, bacteria and foreign invaders, therefore, it has MANY cells for inflammation, allergic reactions and immune reponse**
What are the cellular components of Extracellular matrix?
fixed cells: which develop and remain in place withing the connective tissue. Ex fibroblasts, adipose cells, macrophages and pericytes
transcient cells: originate in bone morrow and circulate the bloodstream. Ex lymphocytes, neutrophils, eosinophils, basophils, monocytes, macrophages and mast cells
Identify the type of tissue here and describe
Dense irregular connective tissue
Contains mostly coarse collagen fibers interwoven into a meshwork that resist stress from all direction. collagen is very tightky packed so theres no space for ground substance. fibroblasts, most abundandt cell, are located between collagen bundle.
It’s located in the dermis of the skin, sheaths of nerves, capsules of spleen, testes, ovary, kidney, and lymph nodes
Identify tissue and parts
Identify tissue and parts
Dense Regular collagenous connective tissue
It has a parallel organization of collagen and resist tensile forces with little ground substance. Thin sheet like fibroblast are located between bundles of collagen.
Active fibroblasts show ______ _____ ______ _____ and ______
Active fibroblasts show abundant rough endoplasmic reticulum and nuclei
What are macrophages?
Mononuclear phagocytic system and are divided in two groups: phagocytes and antigen presenting cells. These cells phagocytose foreign substances and damaged senescent cells as cellular debirs
All:
arise from stem cell in bone marrow —> monocytes—-> macrophages (monocytes circulate the blood and signaling lead them to connective tissue where they mature and become macrophages)
have lysosomes
capable of phagocytosis
display receptors for complement
Elastic Fibers
hydrophobic fiber produced by fibroblast. Formed by interaction of elastin and fibrillin. This give elasticity to the tossues and allow them to recoil after stretching. Microfibrils are important in this fibers
Thinnr than collgen fibers
Stain: take acidic dye better than collagen
special dye: orcein or resorcin-fuchsin
What are the cells of mononuclear phagocyte system? (tipos de macrophagos)
- monocyte:
- in liver
- precursos of macrophages
- macrophage:
- connective tissue, lymphoid organs, lungs, bone marrow
- prodcution of cytokines, chemotactic factors and other molecules in inflammation, antigen presentation
- Kupffer cells :
- liver
- same as macrophages
- microglial cell:
- in CNS
- same as macrophages
- langherhans cell:
- epidermis of skin
- antigen processing and presentation
- dendritic cell:
- lymph nodes, spleen
- antigen processing and presentation
- osteoclast (from fusion of several macrophages):
- bone
- localized digestion of bone matrix
- mulinuclear giant cell: (from fussion of several macrophages)
- in connective tissue under various pathological conditions
what is lamina proria?
loose connective tissue of mucous membranes as alimentary canal
Describe dense connective tissue
In comparison with loose connective tissue has MORE fibers and FEWER cells.
Theres two types: dense irregular and dense regular
Dense regular elastic connective tissue
It has coarse branching elastic fibers with only a few collagen fibers. It’s present in blood cells, ligamentum flavum of the vertebral column, and the suspensory ligament of the penis
Connective Tissue Fibers
proteins that determine tensile properties of support tissues.
Major 4:
collagen
fibrillin
elastin
fibronectin
Collagen Fibers
family of proteins and sre the most important fibrillar extracellular matrix components. They are flexible, high tensile strength
Masson’s stain- light green
Acidic dyes- readily with eosin
Mallory - anylin blue
Families of collagen are:
fibrillar collagen: 1,2,3,5,11
short-chain collagen: 8,10
basement membrane collagens: 4
other collagen: 6,7,13
1,2,3 are arranged as rope like fibrils and are the main forms of fibrillar collagen
Reticulin fibers
proide supporting framework for the cellular constituents of various tissues and organs
thin fibrils of type 3 collagen
Stain: PAS, black
microfibirls are prominent in elastic containing EM like
lung, skin, blood vessel walls
Marfan’s syndrome
abnormal expression of the fibrillin gene, autosomal dominant connective tissue disorder. Abnormal elastic tissue because of absence of elastin-associated fibrillin microfibers
What are a few functions of bone?
- provide solid support
- protect organs
- reservoir for calcium and phosphate
- allows us to move
- have cavities for bone morrow
DESCRIBE THE DEVELOPMENT OF THE OSTEON
Osteoclast begin to dig a hole and at somepoint they die and leave a hole. this hole its gonna fill up with vessels, osteoblast. Osteoblast will create bone.
What is the osteon?
It can also be known as Harvesian system. Are concentric lamellae that surrounds a canal in which are blood vessels, nerves and endosteum.
What is the cement line?
boundary of an osteon
Describe some of the structures seen in bone.
picture:
A schematic overview of the basic features of bone, including the three key cell types: osteocytes, osteoblasts, and osteoclasts; their usual locations; and the typical lamellar organization of bone. Osteoblasts secrete the matrix that then hardens by calcification, trapping the differentiating cells now called osteocytes in individual lacunae. Osteocytes maintain the calcified matrix and receive nutrients from microvasculature in the central canals of the osteons via very small channels called canaliculi that interconnect the lacunae. Osteoclasts are monocyte-derived cells in bone required for bone remodeling.
The periosteum consists of dense connective tissue, with a primarily fibrous layer covering a more cellular layer. Bone is vascularized by small vessels that penetrate the matrix from the periosteum. Endosteum covers all trabeculae around the marrow cavities.
What is bone matrix? What are the three major cell types found in bone matrix? Briefly describe them.
- calcified extracellular material. 50% is inorganic: calcium hydroxapatite, mst abundant.
- organic composition: most abundant is collagen type 1 collagen, 90%; proteoglycans and mutiadhesive glycoproteins and osteocalcin, and phosphatase
What are the two linings seen in bone? Describe them.
- All bones are lined on their internal and external surfaces by layers of connective tissue containing osteogenic cells
- endosteum on the internal surface surrounding the marrow cavity
- periosteum on the external surface
By what process do osteoblast secretions become bone matrix?
- Matrix components are secreted at the cell surface in contact with existing bone matrix, producing a layer of unique collagen-rich material called osteoid between the osteoblast layer and the preexisting bone surface.
- Prominent among the noncollagen proteins secreted by osteoblasts is the vitamin K-dependent polypeptide osteocalcin
- also release membrane-enclosed matrix vesicles rich in alkaline phosphatase and other enzymes whose activity raises the local concentration of PO43- ions - together with various glycoproteins binds Ca2+ ions and concentrates this mineral locally
- with high concentrations of both these ions, matrix vesicles serve as foci for the formation of hydroxyapatite [Ca10(PO4)6(OH)2] crystals, the first visible step in calcification
- These crystals grow rapidly by accretion of more mineral and eventually produce a confluent mass of calcified material embedding the collagen fibers and proteoglycans (surrounds collagen fibers and other macromolecules)
How are osteocytes derived? Where are they located? What are some notable structures that are observed in osteocytes?
- some osteoblasts become surrounded by the material they secrete and then differentiate as osteocytes enclosed singly within the lacunae spaced throughout the mineralized matrix
- During the transition from osteoblasts to osteocytes, the cells extend many long dendritic processes, which also become surrounded by calcifying matrix
- The processes thus come to occupy the many canaliculi, radiating from each lacuna
Where are active osteoblast typically located? How are they fixed in these locations and how do they appear?
- located exclusively at the surfaces of bone matrix
- bound by integrins, typically forming a single layer of cuboidal cells joined by adherent and gap junctions
osteogenesis
formation of bone; two types of ossification: intramembranous and endochrondral. In both processes woven bone is produced first and then replaced with lamellar bone
How do metabolites diffuse in bone?
- unable to diffuse through the calcified matrix of bone
- exchanges between osteocytes and blood capillaries depend on communication through the very thin, cylindrical spaces of the canaliculi
How is histological preparation of bone different than other tissues?
- Because of its hardness, bone cannot be sectioned routinely.
- Bone matrix is usually softened by immersion in a decalcifying solution before paraffin embedding
- or embedded in plastic after fixation and sectioned with a specialized microtome.
What do osteoblast produce? (function)
- organic components of bone matrix, including type I collagen fibers, proteoglycans, (filler) and matricellular glycoproteins such as osteonectin (junction)
- Deposition of the inorganic components of bone also depends on osteoblast activity
After osteoblast synthetic activity is complete, what is their fate?
- some differentiate as osteocytes entrapped in matrix-bound lacunae
- some flatten and cover the matrix surface as bone lining cells
- the majority undergo apoptosis
How does an active osteoclast function?
- the membrane domain that contacts the bone forms a circular sealing zone which binds the cell tightly to the bone matrix and surrounds an area with many surface projections, called the ruffled border
- This circumferential sealing zone allows the formation of a specialized microenvironment between the osteoclast and the matrix in which bone resorption occurs
Explain more in depth how osteoclast preform their function in bone remodeling and how they are regulate to preform this function.
osteoblast sense microcraks in the bone produce RANKL, receptor activator of nucelar factor KB ligand, binds to nearby monocytes to produce multi nucleated osteoclast. The osteoclast secrete lysosomal enzyme (collagenase) and digest and college making the Howship’s lacunae. The osteoclast secretes HCl, and this dissolves hydroxypatite to Ca and PO3. This gets into the blood stream. when they are done they commit suicide.
Osteoblast secrete osteoid seam (mostly collagen) to fill in lacunae. they also secrete Ca and PO3 making hydroxipatite.
How does diffusion occur between osteocytes and blood vessels?
-through the small amount of interstitial fluid in the canaliculi between the bone matrix and the osteocytes and their processes
What is the function of osteocytes?
-communicate with one another and ultimately with nearby osteoblasts and bone lining cells via gap junctions at the ends of their processes
mechanoreceptors- giving orders to other cells to form or deform bones
What are some structural differences seen in osteocytes vs osteoblast?
- almond-shaped osteocytes
- exhibit significantly less RER
- smaller Golgi complexes
- more condensed nuclear chromatin than osteoblasts
What are a few functions of osteocytes?
- maintain the calcified matrix, and their death is followed by rapid matrix resorption
- While sharing most matrix-related activities with osteoblasts, osteocytes also express many different proteins, including factors with paracrine and endocrine effects that help regulate bone remodeling
- The extensive lacunar-canalicular network of these cells and their communication with all other bone cells allow osteocytes to serve as sensitive detectors of stress- or fatigue-induced microdamage in bone and to trigger remedial activity in osteoblasts and osteoclasts
What are osteoclast?
-very large, motile cells with multiple nuclei (Figure 8-6) which are essential for matrix resorption during bone growth and remodeling.
** they are big become comes from monocytes**
Why are osteoclast large in size and multinucleated?
-due to their origin from the fusion of bone marrow-derived monocytes
What is the periosteum ?
outer fibrous layer of dense connective tissue containing: Type 1 Collagen, fibroblast and blood vessels
-Bundles of periosteal collagen, called perforating (or Sharpey) fibers, penetrate the bone matrix and bind the periosteum to the bone.
inner layer: is more cellular and has osteoblasts, bone lining cells and stem cells .
-With the potential to proliferate extensively and produce many new osteoblasts, osteoprogenitor cells play a prominent role in bone growth and repair
What is the endosteum?
inside the bone. Covers the trabeculae and contains: osteoprogenitors/ mesenchymal cells, osteoblast and bone lining cells.
More delicate because we dont have the fibrous part as the periosteum
Location and appearance Woven bone (type of bone)
Irregular and random arrangement of cells and collagen; lightly calcified/ no mineralized. Its replaced by lamellar bone
It is located in developing and growing bones embryonic development; bones fracture
Location and appearance lamellar bone (type of bone)
multiple layers of calcified matrix, organized on sheets around a canal. Each lamella has type 1 collagen with orthogonal orientation ( different directions)
all normal regions of adult
Compact bone
Parallel lamellae or densely packed osteons, with interstitial lamellae
It is located in the thick, outer region of bones
Explain osteoclast development
- It requires two polypeptides produced by osteoblast: M-CSF and RANKL
In areas of bone undergoing resorption, osteoclasts on the bone surface lie where?
-within enzymatically etched depressions or cavities in the matrix known as resorption lacunae (or Howship lacunae)
What are the parts of the long bones?
epiphyses: composed of cancellous bone covered with compact bone.
diaphysis: dense bone with a region of cancellous bone
type of bone in short bones:
cores of spongy bone and covered completely in compact bone
What is osteopetrosis
- characterized by dense, heavy bones (“marble bones”)
- the osteoclasts lack ruffled borders and bone resorption is defective.
- This disorder results in overgrowth and thickening of bones, often with obliteration of the marrow cavities, depressing blood cell formation and causing anemia and the loss of white blood cells.
- The defective osteoclasts in most patients with osteopetrosis have mutations in genes for the cells’ proton-ATPase pumps or chloride channels
Describe both the inorganic and organic contents that make up the bone matrix.
Inorganic Material
- About 50% of the dry weight of bone matrix is inorganic materials
- Calcium hydroxyapatite is most abundant, but bicarbonate, citrate, magnesium, potassium, and sodium ions are also found
- Significant quantities of noncrystalline calcium phosphate are also present
Organic Material
-he organic matter embedded in the calcified matrix is 90% type I collagen, but also includes mostly small proteoglycans and multiadhesive glycoproteins such as osteonectin
What is present on the surface of hydroxyapatite crystals and what is the significance of this
- a hydration layer
- facilitating the exchange of ions between the mineral and body fluids
What substances released in matrix vesicles promote calcification of the matrix?
-Calcium-binding proteins, notably osteocalcin, and the phosphatases released from cells in matrix vesicles promote calcification of the matrix
Why do most tissues rich in type I collagen not undergo calcification?
-they lack osteocalcin and matrix vesicles
endochondral ossification
process in which bone forms by replacing hyaline cartilage because osteoblast invades.
Happens in most bones of the body.
What is a histological phenomenon that occurs in regards to collagen fibers and calcification in bone? What staining property does this give histologically prepared bone?
- The association of minerals with collagen fibers during calcification provides the hardness and resistance required for bone function.
- If a bone is decalcified by a histologist, its shape is preserved but it becomes soft and pliable like other connective tissues.
- Because of its high collagen content, decalcified bone matrix is usually acidophilic.
How many parts have the epiphyseal cartilage plate and their names
zone of reserve
proliferative zone
zone of hypertrophy
zone of calcified cartilage
zone of ossification
cancellous bone or spongy bone
interconnected thin spicules or trabeculae covered by endosteum
its located inner region of bones, adjacent to marrow cavities
trabeculae makes spongy bone “flexible”
Bone marrow is in the middle of the —
bone
type of bone in flat bone:
two layers of compact bone called plates and in the middle has cancellous bone/ diploe
Types of cancellous bones/ organization
- mature lamellar bone- matriz are sheets
- woven bone- newly formed, usually in newborns and are randomly arranged
what happens with low levels of Ca in blood?
parathyroid hormone Its secreted when low Ca levels to allow reabsorption of Ca
what happens with high levels of Ca in blood?
Parathyroid hormone stops being secreted to inhibit reabsorption
What is calcitonin?
hormone produced by parafollicular cells of thyroid gland the lowers blood calcium levels by inhibiting reabsoption
Volkmann’s canals
transverse perforating canals.
intramembranous ossification
process by which bone forms directly from mesenchymal tissue and secretes osteoid, which calcifies, forming irregular areas of woven bone
Most flat bones begins this way– skull jaws, scapula and clavicle
Note:
Newborns have fontanelles on head are areas of skull which the membranous tissue is not yet ossified
Explain how endochondral ossification happens
- Fetal hyaline cartilage model develops
- Osteoblast that differentiate in the perichondrium (early periosteum) produce bone collar around diaphysis.
- primary ossification center forms in the diaphysis
- the chondocytes dies and leave empty spaces. Blood vessels penetrate bone collar and bring stem cells to central region. - secondary ossification centers from in epiphyses (same as 1rat ossification)
- bone replaces cartilage except the articular cartilage (within the joints between long bones) and epiphyseal plates. (you see it in children and let people grow with time)
- epiphyseal plates ossify and form epiphyseal lines when they become bone.
bone collar
produced by osteoblast and impides oxygen and nutrition of chondrocytes causing hypertrophy (swell) and then to release osteocalcin and alkaline phosphatase, calcification.
zone of reserve cartilage
composed of typical hyaline cartilage
proliferative zone
cartilage cells divide repeatedly, enlarge and secrete more type 2 collagen and proteoglycans, and become organized into columns parallel to the long axis of the bone.
zone of hypertrophy
contains swoller, terminally differentiated chrondrocytes which compress the matrix into align spicules and stiffen it by secretion of type X collagen
zone of calcified cartilage
chrondrocytes about to go apoptosis release matrix vesicles and osteocalcin to begin matrix calcification by hydroxypatite crystals.
– where secondary ossification happens
zone of ossification
bone tissue first appears.
Osteoid
unmineralized bone matrix
four basic types of tissue
epithelial, connective, muscular, nervous
Most organs can be divided into __________, which is composed of the cells responsible for the organ’s specialized functions
parenchyma
what is stroma?
cells of which have a supporting role in the organ; always CT except in brain and spinal cord
What are possible shapes of epithelial cells?
columnar, cuboidal, squamous; c ells size and morphology are generally dictated by their function
What is lamina propria
the connective tissue that underlies the epithelia lining the organs of the digestive, respiratory, and urinary systems
what is papillae?
area of contact between the epithelium and connective tissue maybe increased by irregularities at the interface in the form of small evaginations; occur most frequently in epithelial tissues subject to friction (skin and tongue)
what is Basal Pole/ domaine
region of the cell contacting the connective tissue
have specializations include the basal lamina, plasma membrane infoldings, and hemidesmosomes
what is Apical Pole
the opposite end of the basal pole, usually facing a space.
Rich in: ion channels, carrier proteins, glycoproteins, and hydrolytic enzymes, and aquaporins
what is lateral surfaces
regions of cuboidal or columnar cells that adjoin the neighboring cells
Basement membrane
All epithelial cells in contact with subjacent connective tissue have at their basal surfaces a specialized, feltlike sheet of extracellular material referred to as this
Basement membrane
All epithelial cells in contact with subjacent connective tissue have at their basal surfaces a specialized, feltlike sheet of extracellular material referred to as this It has two parts: basal lamina and reticular lamina
What is epitelial tissues?
Are cells which cover surfaces, line body cavities or form glands
What is connective tissue?
Cells that produe an extracellular matrix and serve to link or support other specialized tissues by forming tendons, bone or fatty tissue.
What is connective tissue?
Cells that produe an extracellular matrix and serve to link or support other specialized tissues by forming tendons, bone or fatty tissue.
reticular lamina
layer beneath the basal lamina, this one is more fibrous than basal lamina contains Type III collagen bound by anchoring fibrils of type VII collagen (produced by connective tissue)
Laminin
large glycoproteins that self assemble as a lacelike network immediately below the cells’ basal poles where they are held in place by the transmembrane integrins
The macromolecules in the basal lamina come from the _______
epithelial tissues
The molecules in the basal lamina are:
Type IV collagen laminin nodigen and perlecan
What are the functions of epithelial tissue?
Protection Transcellular transport Secretion Absoption Selective permeability Detection of sensations
Identify the type of cell in the image
Simple squamous epithelium
Identify the type of cell in the image
simple squamous epithelium
Identify the type of cell in the image
simple squamous epithelium
What are the functions of simple squamous epithelium?
- infiltration
- diffusion- lungs
- transport- cardiovascular system
- secretion
- reduction of friction - peritoneal cavity
Types of simple squamous epithelium:
endothelium
mesothelium
endocardium
type of epithelial lining found in blood and lymphatic vessels which form a semipermeable barrier between blood and lymphatic vessels. It can secrete factors for roles.
endothelium
Stratified Squamous Nonkeratinized Epithelium
Lines wet cavities (mouth, esophagus, and vagina) where water loss is not a problem; the flattened cells of the surface layer contain much less keratin, retaining their nuclei and metabolic function
Stratified Squamous Keratinized Epithelium
- epithelium that gives more protection
- Layers of cells composing the free surface are dead, non nucleated, filled with keratin.
Ex. skin
Stratified squamous parakeratinized epithelium
Very similar to keratinized but many cells at the surface retain thei nuclei
Ex. hard palate and gingiva
Identify the type of epithelium cell in the image and its functions
Simple cuboidal epithelium
This cells present a centrally placed nucleus. They made uo ducts of many glands of the body, covering the ovary, composed many kidney tubules.
Identify the type of epithelium and describe
Stratified cuboidal epithelium
contains only two layers of cuboidal cells, lines the duct of cellsof glands
this epithelium are usually specialized for absorption, with apical cilia or microvilvi
simple columnar epithelium
identify type of epithelium and explain
Stratified columnar epithelium
Can be found in the conjunctiva lining the eyelids where is it both protective and mucus secreting. Large ducts in glands.
Identify epithelium and describe
Transitional epitehlium
Its compsed of layers of cells that are either squamous or cuboidal. Its located EXCLUSIVELY in the urinary system
What is mesothelium?
The mesothelium is the epithelium that lines the wall and covers the contents of the closed cavities of the body
Epithelial lining of ventricles and atria of the hear
Endocardium
Simple Epithelia
contain one cell layer; cell shape classification: squamous, cuboidal, or columnar
Name the type of junction and function
Tight junctions/ occluding junction
mostly apical
- prevents diffusion of molecules between adjacent cells
- prevents lateral migration of specialized cell memebrane proteins
Transmembrane proteins in tight junctions:
- occludings
- claudins
- nectins
- junctional adhesive molecules (JAMs)
Identify ZO1, ZO2, ZO3, actin, claudin. occludin, and JAM
The polarity of the cell are determined
by the properties of each domain (apical, basal, basolateral surface of cell) , which are determined by specific lipids and integral membrane proteins
examples of Modifications on apical surface
microvilli, stereocilia and flagella
catenin
protein to whom cytoplasmic cadherins binds, these link to actin filaments (cytoskeleton) with actin binding proteins
How actine filaments of adjacent cells are attached?
are attached by e-cadherine- catenine complex by actinin and vinculin
Lateral domain or pole
Lateral side of the cell and has structures link the lindividual cells together into a functional unit
Junctional complexes
cell adhesion molecules (CAMs)
What are CAMs?
Cell adhesion molecules
What is the CAM’s function?
- control and regulate diverse intracellular processes
- Cell adhesion
- cell proliferation
- cell migration
- intercellular communications
- cell recognition
- regulation of intercellular diffusion barrier
- generation of inmune responses
- apoptosis
Types of cell juntions/junctional complexes:
- occluding junctions
- anchoring junctions
- communicating junctions
Name cell junctions
How the small bowel prevents macromolecules from passing the cells?
Tight junctions in epithelial cells lining
Explain gap junction structure
six closely packed transmembrane channel-forming proteins (connexins) that assember form channel structures called connexons (hemochannels)
Two connexons, one in each cell form the gap junction
_____ attach the basal cellmembrane to the underlying basal lamina; they have strong adhesive properties
Trasmembrane protein responsible for seal between cells:
occludin and claudin, makes sure substances go THROUGH the membrane and not between them
What are anchoring junctions?
provide mechanical stability to epithelial cells so that they can function as a cohesive unit
What are the types of anchoring junctions?
- adherens junctions
- desmosome
- hemodesmosome
Adherent junction/ zonula adherens
LOCATION: located basal to zonulae occludentes
FUNCTION: joins cell membranes and links cytoskeleton of two cells via transmembrane linker proteins
Which proteins are important for adherens junctions?
cadherins y catenins
cadherin
transmembrane glycoproteins of each cell that interact in the presence of Ca2+
What are desmosomes or macula adherens?
resembles a single spot weld and does not form a belt around the cell; are discshaped structures at the surface of one cell that are matched
with identical structures at an adjacent cell surface.
Epithelial desmosomes attach to —
cable like filaments of cytokeratin
What type of cadherins are found in desmosomes?
desmogleins and desmocollins
How desmosomes anchore the cell?
cytoplasmic part of proteins Desmogleins and desmocollins bind to plakoglobins, these link desmoplakina. Desmoplakins bind to intermediate filaments rather than actin.
Type of communication junction
gap junction
The 9 +2 arrangement of cillia is made of —–, whereas arms composed of the protein ——.
The 9 +2 arrangement of cillia is made of -microtubules-, whereas arms composed of the protein -dynein-
IDENTIFY PARTS AND WHAT IT IS
axonema
what are gap junctions?
cell structures that permit direct passage of signaling molecules, small molecules, from one to another
Structure of Microvillus
Each microvillus contains a core of 25 to 30 actin filament bundle, cross-linked to each other by a number of actin-binding proteins, such asespin,fascin,villin, andfimbrin
What is the terminal web?
Is a complex of actin and spectrin molecules as well as intermediate filaments located at the cortex of the epithelial cells.
Structure of stereocilia
Are supported by internal bundles of actin filaments that are cross linked by fimbrin and espin
ezrin: anchors the actin filament to the plasma membrane
Identify structure
erzin
fimbrin
erzin
actin filament
Identify type of epithelium
Simple squamous epithelium
Identify the epithelium
Simple squamous epithelium
Identify the epithelium
Simple columnar epithelium
Identify epithelium
Pseudostratified epithelium,
identify epithelium
simple columnar epithelium
identify epithelium
stratified columnar cells
identify epithelium
simple cuboidal epithelium
identify epithelium
simple cuboidal epithelium
identify epithelium
stratified squamous epithelium
identify the epithelium
squamous non keratinized
identify the epithelium
transitional epithelium
identify the epithelium
type of hemisdosome found in stratified squamous and pseudostratified epithelium
Type 1
How hemidesmosomes commit adhesion?
The half desmosome , structurally, the integrins are the ones which binds to intermediate filaments. Integrins bind primarily to laminin in basal lamina.
Which type of hemisdosomes are present in plama membranes of simple columnar epithelial lining of small and large intestines?
Type 2
Proteins present in type 2 hemidesmosomas
plectin, filamentos de keratina y integrinas
Proteins present in type1 hemidesmosomas
integrina, tonofilamentos, plakin proteins, erbin and CD151
microvilli
in epithelial cells specialized for absorption, the apical surfaces present an array of projections
(it looks like a brush)
brush or striated border
apical surfaces are densely covered with uniform microvilli
stereocilia
restricted to absorptive epithetlial cells lining the the epididymis and the proximal part of ductus deferens in the male reproductive system and on the sensory hair cells of the cochlea (inner ear)
cilia
long projecting structures, larger than microvilli, which contain internal array sof microtubules. most cell types have at least one cilium of variable length usually called a primary cilium which is not motile but is enriched with receptors and signal transduction complexes for detection of light, odors, motion, and flow of liquid past the cells
what is the assembly of each cilium
9 doubles form an array around two central microtubules
what the 9+2 assembly of microtubules is called, cilia?
axoneme
relatively weak and transcient attachments in the basal cell membranes of epithelial cells are called ____
focal adhesion
Focal adhesion structures
Although resembling hemidesmosomes superficially, focal adhesions are smaller, more numerous, and consist of integrins linked indirectly to bundled actin filaments
integrins of focal adhesions are also linked _______________
via paxillin to focal adhesion kinase
What is focal adhesion kinase?
signaling protein which upon integrin binding to laminin or other specific ECM proteins initiates a cascade of intracellular protein phosphorylation affecting cell adhesion, mobility, and gene expression.
Are formed by clusters of α and β integrins that form weak interactions with laminin, type IV collagen, and fibronectin molecules of the basal lamina.
Focal Adhesion
Kartagener syndrome
results from hereditary defects in the ciliary dynein that would normally provide the energy for ciliary bending
It can cause:
Lung infections.•Immotile sperm
What is the function of the terminal web?
Provides support and give rigidity to the microvilli
