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