Exam 1 Flashcards
what is the function?
neutrophil
kill/phago bacteria
- azurophillic primary granules (lysosomes)
- MPO: HClO3, other toxic bac agents
- lysozyme: degrade cell wall
- defensins: cysteine-rich, disrupt cell memb
- specific secondayr granules
- collagenase (ECM degrading)
- deliv bac to phagolysosomes
Cryosection
-Rapid processing of tissues -Specimen is rapidly frozen in liquid nitrogen -Cryostat – special microtome to cut the block Uses : Onco-surgery and histochemical study
Brown adipose tissue – multilocular adipocytes
White adipose tissue also functions as…
endocrine
leptin = prod by adipocytes in proportion to body fat
- Binds to receptors in hypothalamus
- Acts to ↓food intake, ↑ energy expenditure, and ↓ fat stores
- Most obese humans produce adequate leptin, but target cells not responsive
Elastic Cartilage
- Matrix composition similar to hyaline + elastic fibers
- Requires special stains to visualize elastic fibers
–E.g. Verhoeff, Weigert resorcin fuscin or silver stain
what is cell-cycling activated by?
•mitogens or growth factors
these are… func?
Macrophages: Phagocytic activity
how do Marrow cells enter circulation
by passing through discontinuous sinusoidal endothelium
T-tubule System
A particular feature of this epithelium is the intermediate filament composition. In order to highlight their intermediate filament composition using immunohistochemistry, an antibody should be directed at which of the following?
A.Vimentin
B.Desmin
C.Dynein
D.Cytokeratin
E.Glial fibrillary acidic protein
Cytokeratin
immunopositive staining on stratified squamous keratinized epithelium.
The hematocrit is the volume of packed RBCs per volume of blood:
~45% of whole blood volume
Blood volume in average adult:
5 L
After performing a brain biopsy, you see the picture below under the microscope. Which of the following statements would NOT be applicable to the cell in the center of the photomicrograph?
(A)It is active in protein synthesis
(B)It has a large prominent nucleus
(C)It has a visible nucleolus
(D)It is active in ribosome synthesis
(E)It contains abundant nuclear heterochromatin
(A)It contains abundant nuclear heterochromatin
This is CARDIAC muscle! Atrial myocytes release a hormone called Atrial Natriuretric Peptide (ANP) that acts on the kidney to release volume/sodium.
PS…What’s that nice golden stuff in the pic? Thats HEMOSIDEREN! It symbolizes damage and broken down RBCs that have HEMOglobin which contains iron.
Oligodendrocytes
- Small cells that are active in the formation and maintenance of myelin in the CNS.
- Insulates CNS axons.
- Allows faster action potential propagation.
- Derived from neuroectoderm
- Each oligodendrocyte myelinates multiple CNS axons (up to 30 each)
- Predominant type of glial cell in white matter
Gray & White Matter - and locations
Gray Matter: where most neuronal perikarya occurs (most cellular portion)
White matter: where the axons are concentrated
In the brain:
- Gray matter is peripheral
- White matter is central
Exception: Basal ganglia
In the spine:
- Gray matter is central
- White matter is peripheral
Hyaluronate
differs from other gags
- Exceedingly long rigid molecule (1000’s of sugars)
- Not sulfated
- Does not form proteoglycan, however……
- Proteoglycan (aggrecan) binds to hyaluronan via link protein forming giant proteoglycan aggregates
Hematopoietic stem cell
A single pluripotent hematopoietic stem cell gives rise to both myeloid and lymphoid lineages
Compare TEM and SEM
TEM:
Where electrons pass through specimen – TEM appears brighter or electron lucent
Where electrons absorbed/deflected by specimen – TEM appears darker or electron dense
SEM:
only surface view of the specimen with striking 3D quality
Inside of cells can be analyzed after exposure by sectioning
Endomysium
•Delicate loose CT around each fiber
–Includes basal lamina synthesized by each myofiber plus reticular fibers
Adipose tissue - Functions (7)
- Responds to nervous and hormonal stimuli
- Secretes hormones – an endocrine tissue
- Conducts heat poorly – insulates body
- Brown fat deposits – heat production
- Cushions vital organs
- Shock absorber – palms and soles
- Helps shape body surface
Mucoid connective tissue
(Wharton’s jelly)
Two types of adipose tissue
•White (unilocular) adipose tissue
–One very large droplet of whitish-yellow fat
•Brown (multilocular) adipose tissue
–Multiple lipid droplets
–Abundant mitochondria
–Darker appearance
function?
platelet
from proplatelet projections into sinosoid of bone marrow
pinching off creates MARGINAL BUNDLE (MB) - -microtub and actin that helps maintain shape when pinched off from megakaryoctye
Regenerative Capabilities of smooth M
•Higher capability for regeneration
–Actually can repair itself
A student is looking at a transmission EM image of skeletal muscle. The student notices that multiple sarcomeres are evident in cross section view and describes multiple thin filament profiles organized around a thick filament. Which portion of the sarcomere is the student likely observing?
(A)I band
(B)Z band
(C)H band
(D)M line
(E)A band
A band
Hyaline Cartilage
- Most common type (serves as template for skeleton in the embryo)
- ECM contents:
–Chondroitin sulfate, keratan sulfate, hyaluronic acid, chondronectin
–Plus collagen type II
•Matrix is basophillic under H&E staining
barr body
A
Which cell is more active?
Left
- Lymphocyte (resting)-Low metabolic activity
Right:
- Neuron-Metabolically active
Usain Bolt and I are both World Champion sprinters. He beat me one year after I pulled a hammy and I had to rest myself. I have been out of the sprinting game for many years now and have not done much but sit on the couch eating Takis while Usain continues his sprinting activities. What type of skeletal muscle fibers predominate in Usain?
A.Type 1A
B.Type 2B
C.Type 2A
D.Gamma motorneurons
E.You’re a liar and Takis are delicious.
lymphocyte, monocyte
duchenne’s muscular dystrophy
Lacunae
•space. Cavity of matrix where chondrocyte is located.
The image below illustrates an autoimmune condition known as pemphigus vulgaris. Patients suffering from pemphigus vulgaris have autoantibodies that attack desmosomes. Which of the following would be the likely target for these antibodies?
A.Actin
B.Calbindin
C.Claudin
D.Connexins
E.Desmoglein
.Desmoglein
theses are…
POLYRIBOSOMES
FREE AND ATTACHED TO MEMBRANES OF RER
Dendritic Spines
The homologous chromosomes pair and exchange the genetic material during which of the following phases of cell division?
(A)Prophase I
(B)Metaphase I
(C)Anaphase I
(D)Prophase II
(E)Metaphase II
Prophase I
Which of the following structures appear eosinophilic in routine hematoxylin and eosin staining of paraffin sections?
(A)Nucleus
(B)Nucleolus
(C)Lipid
(D)Collagen
(E)Ribosomes
Collagen
Fascia adherens
- Ribbon-like structure
- Stabilizes non-epithelial tissue
- Similar to Z. adherens
G2 /M checkpoint
•ensures that DNA replication is complete
what type of M has which thick filament?
smooth, skeletal
Receptor-mediated endocytosis
receptors that bind specific molecules (ligands). When many such receptors are bound by their ligands, they aggregate in one membrane region, which then invaginates and pinches off to create a vesicle or endosome containing both the receptors and the bound ligands.
Proerythroblast→ Basophilic erythroblast→ Polychromatophilic erythroblast→ Orthochromatophilic erythroblast→ Reticulocyte
TELOPHASE
•Two sets of chromosomes arrive at opposite poles
•
- Spindle depolymerizes.
- New nuclear envelope assembles
•
•Contractile ring starts to form
green?
blue?
pink?
Microtubules (green)
Chromosomal DNA (blue)
Kinetochores (pink)
RECEPTOR-MEDIAted endocytosis steps
- Ligands bind at high affinity to specific surface receptors
- associate with specific cytoplasmic proteins: clathrin and adaptor proteins
- aggregate in membrane regions to form coated pits.
- Clathrin = invagination of the pits, and another -peripheral membrane protein
- dynamin (peripheral membrane protein) forms constricting loops around the developing neck of the pit = pinch off as a coated vesicle.
The internalized vesicles lose their clathrin coats and -usually merge by membrane fusion with other endosomal vesicles. Ligands may have different fates within the endosomal compartment:
- Receptors and ligands may be carried to late endosomes and then to lysosomes for degradation.
- Ligands may be released internally and the receptors recycled to the cell surface.
- Vesicles may move to and fuse with another cell surface, where the ligands are released again outside the cell (transcytosis).
cardiac
Lipid stains
Oil red O, Sudan black
organic solvents (those used in h&e) degrade all the fat so left stain is just empty cells
Connective tissues characteristics and what kinds of tissues they describe
- Tough and flexible- tendons, dermis
- Hard and dense – bone
- Resilient and shock absorbing – cartilage
- Soft and transparent – vitreous of eye
Highly variable structure and physical/mechanical properties
PROMETAPHASE
Starts abruptly with breakdown nuclear envelope
Chromosomes attach microtubules via kinetochores which attach to centromere
- can now undergo movement
•GFAP stain: star shaped cell
A mother brings her 8 year-old boy to your office with the complaint of recurrent respiratory infections. The boy is later diagnosed with a genetic disorder that interferes with the motility of the cilia. Which of the following structures are responsible for the ciliary motility?
(A)Actin filaments
(B)Microtubules
(C)Lamins
(D)Myosin filaments
(E)Desmins
Microtubules
Nuc Func
- Stores the genetic material in DNA of chromosomes. (Storage and replication)
- Synthesis of RNA (Transcription).
- Directs protein synthesis.
- Contains all the enzymes for replication and repair of newly synthesized DNA as well as transcription and processing of precursor RNA molecules
2 friends, George and Bud, were playing around one day quizzing each other with UMich images for Histo. George points to a specimen that is obviously skeletal muscle, proclaiming that it is cardiac instead. Bud lashes out at George yelling, “Geez, George that’s obviously skeletal muscle! What are you brain dead???”
If George actually did not have a functional nervous system, what description matches a type of muscle that would still be functioning in George?
A.Caveolae, electron dense bodies and fusiform appearance
B.Striated, multinucleated and fused
C.Uninucleated, branched, gap junctions, triads
D.Fascia adherens, eosinophillic, T tubules
Smooth muscle in the gut and viscera work without nervous system stimulation. Contraction waves work through gap junctions.
B describes skeletal muscle and C would describe cardiac muscle if “triads” was changed to “diads”. Btw, where do you find triads in skeletal muscle? The AI band junction
And diads in cardiac muscle? The Z line
protein A
purified from s. aureus
bind to Fc regions of antibodies
Some important GAGs
- Hyaluronan
- Chondoitin sulfate
- Dermatan sulfate
- Keratan sulfate
- Heparan sulfate
Polarizing microscopy
Polarizing light.
Allows visualization of material with repetitive, periodic macromolecular structure.
NUCLEAR PORE COMPLEX
In order of development, what are the 6 cell types of granulopoiesis?
a. Promyelocyte, myeloblast, myelocyte, metamyelocyte, band, mature granulocyte
b. Myeloblast, promyelocyte, myelocyte, metamyelocyte, band, mature myelocyte
c. Myeloblast, promyelocyte, myelocyte, metamyelocyte, band, mature granulocyte
d. Promyeloblast, myeloblast, myelocyte, metamyelocyte, band, mature granulocyte
Myeloblast, promyelocyte, myelocyte, metamyelocyte, band, mature granulocyte
Pluripotent cells
•Able to form all embryonic cell types; inner cell mass of blastocyst.
Osteoblasts
- Found at the surface of bone matrix
- Osteoid deposition
Trimming
to expose the tissue for sectioning
Which of the following organelles release cytochrome c to activate apoptosis?
A.Rough endoplasmic reticulum
B.Smooth endoplasmic reticulum
C.Nucleus
D.Mitochondria
E.Golgi complex
Mitochondria
Monocytopoiesis
Monoblast→
Promonocyte→
Monocyte→
what kind of m is this?
smooth
dynanmin
pinches neck around clathrin-coated invag
peripheral memb protein
what is happening here?
Orthochromatophilic erythroblast extruding nucleus
What is the function of this?
Site of rRNA synthesis
Ribosomal proteins enter through the nuclear pores
Assembly of ribosomes with rRNA
Release of ribosomes into the cytoplasm through nuclear pores
Resorcin-fuchsin
Calcitonin
–released by thyroid parafollicular cells. Slows matrix resorption and gradually lowers calcium levels (WHEN CALCIUM IS HIGH).
sudan black
x-links in elastin
Oxidized lysines on two different elastin molecules condense as desmosine ring forming covalent crosslinks
(incomplete sheets)
in wall of aorta
Duchenne’s Muscular Dystrophy
Dystrophin links the cytoskeleton and ECM, and reinforces and stabilizes the sarcolemma during stress of muscle contraction.
When dystrophin is absent, the sarcolemma is disrupted, allowing calcium entry, which causes necrosis of muscle fibers
May be a precursor of plasma cells
mito
structure and associated filament
Microtubules in mitotic spindle
Found encircling muscle fascicles
purkinje layer of cerebellum
- thin middle layer consisting of very large neurons.
- Their dendrites extend throughout the molecular layer as a branching basket of nerve fibers. Axons through granular layer.
type 1 collagen characteristics
- Every third amino acid is glycine
- Rich in proline and lysine
- Proline and lysine hydroxylated by proline and lysine hydroxylase – requires vitamin C
- Hydrogen bonding of hydroxyproline stabilizes the triple helix
They are the same cell type as those in the bottom picture containing bluish material
An actively dividing cell was examined under microscope. It exhibited cleavage furrow and appeared to undergo cytokinesis. The cell is in which of the following stages of mitosis?
A.Prophase
B.Metaphase
C.Anaphase
D.Telophase
E.Prometaphase
Telophase
Integrins
Transmembrane link between ECM and cytoskeleton
Metal impregnation
•Silver stain: Reticular fibers, Nerve elements
Apoptosis
Programmed cell death.
Rapid
No cell leakage = no inflammation.
Controlled by Bcl-2 proteins on mitochondrial membrane.
Triggered by tumor suppressor proteins.
- p53
3rd arrow? structure and function
desmosome
structure: intermediate filaments (keratins)
function: strong attachment points between adjacent cells (velcro)
stratified cuboidal: distribution and function
sweat glands, developing ovarian follicles
protection, secretion
Epithelial Tissues composition
closely aggregated cells - with little ECM
strong adhesions - cellular sheets
Epithelial Tissues Func
- Covering, lining, protection (e.g. skin)
- Absorption (e.g. intestines)
- Secretion (e.g. epithelium of glands)
- Contractility (e.g. myoepithelial cells)
Clearing
Alcohol replaced by toluene / xylene
Apoptotic changes
Loss of mitochondrial function via cytochrome release by caspase activation.
Fragmentation of DNA by endonuclease.
Shrinkage of nucleus and cytoplasm by pyknotic nucleus.
Cell membrane blebbing
Apoptotic bodies form
phagocytosis
Epithelial Tissue Characteristics
- Avascular
- Face a lumen
- Rest atop connective tissue (e.g. lamina propria of the GI system) – support and nutrition
–Papillae – increase contact between epithelium and connective tissue
- Produce a layer of extracellular material (basal lamina/ basement membrane)
- Show polarity
–Apical
–Basal
–Lateral
Cell / Tissue Culture
- Maintenance of live tissue in vitro.
- Primary cell culture à Transformation à Permanent cell line.
•
•Uses:
–To understand the molecular changes in cancer and various infections;
–To learn about the location and functions of the components of cytoskeleton
function of this?
basophil
less than 1%
heparin, histamine, leukotrienes
- heparin = why so basophillic
- anaphylactic shock
receptors of IgE
LIKE MAST CELLS!!
Platelets have several roles in hemostasis
- Platelets aggregate at sites of injury to control blood loss from leaks in the microvasculature
- Platelets promote formation of a fibrin blood clot
- Cause clot retraction
- Play a role in activating plasmin to lyse blood clot
Molecular layer of cerebellum
•thick outer layer with much neuropil and scattered neuronal cell bodies.
Skeletal M type IIa
•Fast Type IIb (oxidative-glycolytic)
–An intermediate of Type I and IIa
pic of? func?
label pic
Adipocytes specialized for storage of neutral fat or less commonly production of heat
Anaxonic neuron
- Lacks true axons.
- Present in the CNS
- Do not produce action potential
- Regulate local electrical charges of adjacent neurons
Multiadhesive glycoproteins func:
–Adhesion of cells to ECM
–Assembly and stabilization of ECM
–Cell migration through ECM
–Bidirectional connection between cells and ECM → physical orientation of both cells and fibers
Leukocyte general func
migration to site of injury or infection is an important component of the inflammatory response
Basophils
•Specific basophilic granules contain mediators similar to those in connective tissue mast cells
–Heparin, histamine, and eosinophil chemotactic factor
–Strong basophilia due to heparin and other GAGs
- Surface receptors for IgE
- Appear to supplement the functions of mast cells by migrating into connective tissues
–Both mast cells and basophil central to allergic responses
Granular layer of cerebellum
a thick inner containing various very small, densely packed neurons and not much neuropil.
STEM CELLS
- Undifferentiated cells that renew the differentiated cells.
- In tissues with rapid cell turn over.
- Asymmetric division: One of the daughter cells remains as stem cell.
It is a precursor of tissue macrophages
RER function
Synthesis of membrane-packaged proteins
(secretory, lysosomal, and membrane protein)
Interference microscopy
- Modification of phase contrast microscopy – contrast is further enhanced.
- Differential interference optics are used.
- Mass of the cellular components could be calculated.
- More apparent 3-D image is produced.
Key features of meiosis
Meiosis I – Crossing over (genetic recombination). Separation of homologous chromosomes →haploid cells
Meiosis II – Separation of sister chromatids
NM Jxn
what is this? structure and function
gap Junctions
structure: connexin
function: direct transfer of ions/molecules
classes of intermediate filaments
cytokeratins - epithelium
desmin - muscle
vimentin - mesenchymal fibroblasts, cells
Sharpey fibers
periosteum
METAPHASE
•Chromatids most condensed
- Chromosomes aligned at equator (equatorial plate)
•Kinetochores attached to opposite spindle poles
Connective tissue cells: Permanent cells
–Fibroblasts
–Macrophages
–Adipocytes
–Mast cells
–Adult stem cells
CHOLESTEROL
HELPS MAINTAIN THE APPROPRIATE LEVEL OF MEMBRANE FLUIDITY
Embryonic mesenchyme
A 45 year old female undergoes a lumpectomy which confirmed a malignant mass in the right breast. As her oncologist you wish to determine how many copies (if any) of a particular oncogene (HER2) the patient’s tumor expresses. Which of the following techniques would be used to determine the number of copies of this gene?
(A) Hematoxylin and Eosin staining
(B) Fluorescent immunohistochemistry
(C) Fluorescent in situ hybridization
(D) Transmission electron microscopy
(E) Silver staining
Fluorescent in situ hybridization
Basal Lamina
- From Basal Pole
- Laminin – Main structural component
- Type IV collagen
- Entactin/nidogen & perlecan = adhesives
•
- CT contribution
- Type III & VII collagen
Ex of acidic dyes
Eosin, Acid fuschin
what is this showing?
EM of apoptotic cells
what triggers apoptosis?
•Triggered by tumor suppressor proteins.
e.g.: p53
Platelets
- Very small, non-nucleated membrane-bound fragments of cytoplasm derived from megakaryocytes in bone marrow
- Important for hemostasis
- Circulating platelet life span 10 days
Endoneurium
–Loose CT surrounding individual nerve fibers
–Merge w/ type IV collagen (laminin et al.) of basal lamina
A.They are derived from polyploid bone marrow cells
what is 2nd arrow pointing to? structure and function?
zona adherens
structure: actin
function: joins cytoskeletons of adjacent cells, strenghten/stab tight jxns
It is a phagocytic cell
CNS
- Neuron body (Gray matter)
- Axons (White matter)
- What is the physiologic cause of the presence of the inclusion?
- A. Incomplete glycogen breakdown
- B. Breakdown of lipids
- C. Byproduct of lysosomal degradation
- D. Denatured ferritin proteins
C Byproduct of Lysosomal degradation
This is Lipofuscin: “wear and tear” pigment. Seen in long lived cells (i.e. neurons, skeletal muscle)
Barrett’s Esophagus
Acid reflux disease causes irritation to the mucosa of the esophagus which can result in glandular metaplasia (i.e. change from one epithelium type to another; illustrated below).
Osteocytes
intermediate filaments are composed of:
fibrous protein subunits
periosteum
Axonal Transport
Microtubules are involved in the axoplasmic transport in neurons.
Molecular motor proteins
Transport cellular cargo towards opposite end of microtubule tracks
Dynein: retrograde to microtubules (+à-)
Kinesin: anterograde to microtubule (- à+)
An active mammary gland is shown in the photomicrograph below. Release of the secretory products of this gland is accomplished by which of the following methods?
A.Merocrine
B.Apocrine
C.Endocrine
D.Holocrine
E.Myocrine
Apocrine
Phase-contrast microscopy
- Thin, translucent, unstained sections.
- Special lens – Recognizes the structures with different refractive indexes based on the retardation of light
- Appear light/ dark – Resolution is not good
- Living tissues visualized à used in tissue culture
resolution in electron microscopy greatly exceed that of light microscophy due to?
wavelength of electrons in microscope beam is shorter than that of a beam of light
Phagocytosis
large folds called pseudopodia that engulf particles - then invag
internalized in cytoplasmic vacuole or phagosome
A.Type I collagen abundantly present in the matrix
Pemphigus vulgaris
- Autoimmune disorder that involves blistering and sores (erosions) of the skin and mucus membranes
- Achantolysis=loss of intercellular connection
PERIODIC ACID-SCHIFF (PAS):
A “SPECIAL STAIN” FOR CARBOHYDRATES
Stains glycoprotein, glycogen and mucin (oligosaccharide and polysaccharides)
osteoblasts synth:
•Synthesize type I collagen and ground substance
–Ground substance = GAG’s, glycoproteins
–Also osteonectin (anchors mineral components to collagen
–Osteocalcin
Which of the following structures appear eosinophilic in routine hematoxylin and eosin staining of paraffin sections?
(A)Nucleus
(B)Nucleolus
(C)Lipid
(D)Collagen
(E)Ribosomes
(D)Collagen
Perimysium
•CT septa from epimysium
–Envelops fascicles
what is function of this?
golgi apparatus
MODIFIES, SORTS PACKAGES PROTEINS
Acidic dyes
stain acidophilic (basic/ cationic) structures (mitochondria, collagen, protein granules).
Erythropoiesis:
Basophilic erythroblast
Polychromatophilic erythroblast
Orthochromatophilic erythroblast
Reticulocyte
Erythrocyte
these are..
Permanent cells:
Fibroblasts – Most common connective tissue cell
Which protein component of the nucleus is closely related to the nuclear membrane and stabilizes it?
A. Microtubule
B. Microfilament
C. Cyclin
D. Actin
E. Lamin
Lamin
Other special stains
- Elastic fibers – Orcein/ Resorcin.
- Collagen – Van Gieson Method – Collagen: pinkish-red, muscle: yellow.
Totipotent cells
•Able to form all embryonic and extraembryonic tissue; zygote and early blastomeres.
What is the sex of this patient?
Woman! Presence of Barr Body
what kind of cell and its distribution
Ovary & Thyroid & urninary
a) Renal collecting tubules, (b) thyroid cells, ( c ) Ovarian mesothelium
label
Confocal microscopy
Uses laser beam instead of ordinary light.
Scans successive focal planes with focused light beam.
Allows a 3D reconstruction.
Permanent cells
–Cells that cannot divide.
- exit the cell cycle and remain for ever in G0 phase
–e.g.: Neurons, cardiac muscle
(A) 30-nm thick chromatin fiber - packed nucleosomes
(B) “Beads-on-a-string” - unpacked nucleosomes
Factors enhancing lipid storage (lipogenesis)
•Dietary abundance
–Dietary fat absorbed by intestinal epithelium → chylomicrons
–Dietary glucose converted to triglycerides in liver → very low-density lipoproteins (VLDLs)
•Insulin
–Insulin - ↑glucose uptake and triglyceride synthesis by adipocytes
A.Disruption of the growth plates is of concern in this patient
this is?
A oligodendroglioma case shows conspicuous network of branching capillaries
Elastic Cartilage
More than just an envelope to the cell, the cell membrane or plasmalemma carries out many functions that are fundamental to the survival of the cell and ultimately the organism. Which of the following features is not characteristic of a cell’s plasma membrane?
(A)Allows the lateral movement of proteins across its surface
(B)Cell-to-cell recognition
(C)Membrane proteins are linked to the cytoskeleton
(D)Energy synthesis via oxidative phosphorylation
(E)Allows passive diffusion of certain molecules
●
(A)Energy synthesis via oxidative phosphorylation
Specialized connective tissue:
Reticular connective tissue
Cartilage Growth
•The result of 2 processes
- Interstitial growth – mitotic division of pre-existing chondrocytes.
- Appositional growth – differentiation of perichondrial cells.
type 1 skeletal M
–Slow contractions, prolonged time, little fatigue
–Rich in mitochondria, capillaries, and abundant myoglobins (darker appearance)
how are GAGs linked?
covalently linked to a core protein to form proteoglycans
- Syndecan: transmembrane core - cell to ECM
- Aggrecan: cartilage
- Decorin: binds fibrils of type I collagen
Factors enhancing lipid mobilization (lipolysis)
•Hormones
–Norepinephrine and peptide hormones (glucagon, GH)
•Autonomic innervation
–Norepinephrine released by sympathetic postganglionic nerves
glycocalyx
CARBOHYDRATE COAT ON EXTERNAL CELL SURFACE
what are arrows pointing at?
light = golgi
dark = nucleus
plasma cells have well-developed golgi
Penicillin can be used to treat certain kinds of bacterial meningitis as it can penetrate the blood brain barrier. Which of the following best describes the blood brain barrier?
(A)Capillary and ependymal cell apposition in the ventricles
(B)Pia mater binding to astrocytes at the brain surface
(C)Tight junctions between endothelial cells in brain capillaries
(D)Microglial processes surrounding the venous sinuses
(E)Desmosomes of adjacent neuronal soma
c
Here is a bronchial biopsy from a smoker. Prolonged smoking has caused irritation to the bronchial epithelium resulting in change of the epithelium called “metaplasia”. Which of the following choices describes the transition from normal epithelium (1)to abnormal epithelium (2)?
A.Pseudostratified columnar epithelium with stereocilia à Simple cuboidal epithelium
●
B.Stratified squamous non-keratinized epithelium à Stratified columnar epithelium
●
C.Simple columnar epithelium à Pseudostratified columnar epithelium with cilia
D.Pseudostratified columnar epithelium with cilia à Stratified squamous non-keratinized epithelium
●
E.Stratified columnar epithelium à Simple cuboidal epithelium
A.Pseudostratified columnar epithelium with cilia à Stratified squamous non-keratinized epithelium
Aneuploidy
•Failure of the homologous chromosomes to separate à Abnormal number of chromosomes.
ex: trisomy 21: down syndrome
Epineurium
•– External nerve covering
–Dense irregular CT
Infiltration
Toluene replaced by molten paraffin wax
Oligodendrocytes stain presentation
- Nissl stain: Small nuclei with dark chromatin and little cytoplasm
- H&E stain: Fried egg appearance
What is true regarding this cell?
A.Actin is the most important fiber in the production of this cell’s progeny
A.It lacks granules
A.Its genetic makeup is similar to other somatic cells
A.It has multiple nuclei
A.It is confined to one developing area of the marrow
A.It has multiple nuclei - megakaryocytes have multiple nuclei from cell divisions w/o separation
Which of the following stains is best used to stain the tissue shown in this image?
(A)PAS stain
(B)Hematoxylin and eosin
(C)Trichrome stain
(D)Sudan black
(E)Orcein
(d)Sudan black
Progenitor cells
colony forming units (CFUs), give rise to separate pathways committed to erythropoiesis, thrombopoiesis, granulopoiesis, monocytopoiesis, or lymphopoiesis
Neurulation
beginning formation of the CNS
neural plate —> neural tube
ENZYME HISTOCHEMISTRY
A method for localizing a specific enzymatic activity (phosphatases, dehydrogenases, peroxidase) in cellular structures
Differentiating cells
have long G1 phase
remain temporarily in G0 phase.
what is this. structure and function
hemidesmosomes
structure: integrins, intermediate filaments
function: achors cytoskeleton to basal lamina
Cartilage function
•Resist mechanical stress w/o deformation
Inhibitory neuroT
g-aminobutyric acid (GABA) & glycine
•Cause membrane hyperpolarization (Cl- mediated)
sebaceous Gland
Holocrine Secretion
While doing an elective rotation in gastroenterology a 4th year D.O. student is asked by the chief resident to observe an esophageal biopsy sample obtained by endoscopy. Despite this patient’s chief complaint of severe and persistent heartburn you notice that his biopsy shows normal esophageal epithelium. Which of the following images (see next slide) depicts the epithelial lining that this student has observed?
c
Schwann Cells (Neurolemmocytes)
Cerebellar Cortex
What structure is predominate in this?
(A)The site of rRNA synthesis
(B) The site of ribosomal protein synthesis
(C) The site of transport proteins
(D) Transcriptionally inactive chromatin
(E)The site of translation of mRNA
(A)The site of rRNA synthesis - nucleolus
(B) The site of ribosomal protein synthesis - nucleus
(C) The site of transport proteins
(D) Transcriptionally inactive chromatin - heterochromatin (around lamina)
(E)The site of translation of mRNA
Regenerative Capabilities of skeletal M
•Limited capacity for regeneration
–Satellite cells
Cerebrospinal Fluid
- CSF is made by ependymal cells of choroid plexus.
- The choroid plexus consists of ependyma and vascularized pia mater and projects many thin folds from certain walls of the ventricles.
- The CSF It is reabsorbed by arachnoid granulations and then drains into dural venous sinuses.
Multiadhesive glycoproteins characteristics:
- Very large molecules with branched oligosaccharide chains
- Multiple binding sites for cell surface receptors and matrix macromolecules
- –Cell surface receptors – integrins
- –Matrix macromolecules- collagens, GAGs, proteoglycans
what are functions of this?
eosinophil
parasidic worms, local imflammation
major basic protein
- acidophillia
- 50% total granule protein
remove antigen-antibody complexes via phago
HIGH IN ASTHMA PTS!!
Embedding
block of paraffin hardened
THE FLUID MOSAIC MODEL DESCRIBES MEMBRANES AS
“protein icebergs in a lipid sea”
hematoxylin and eosin (H&E)
Q3. Local anesthetics are important for numerous procedures that involve numbing a particular area for pain (e.g. dental, sutures, etc). This medication works by inhibiting the propagation of the neuro action potential. Which of the following best explains the effects of local anesthetics?
(A)Decreasing the number of terminal boutons
(B)Blocking voltage gated Na+ channels
(C)Inhibiting the synthesis of synaptic vesicles
(D)Inhibiting microtubule synthesis
(E)Removing neurotransmitter from the synaptic space
●
Blocking voltage gated Na+ channels
TYPES OF HETEROCHROMATIN
Constitutive
- always inactive and condensed.
- Ex: Centromere, Telomere
Facultative
- Can exist in both forms
- Ex: Barr body
Osteomalacia is characterized by the presence of demineralized bone matrix. What is another name for immature bone matrix that is present in this condition?
A.Chondronectin
B.Osteonectin
C.Osteoid
D.Hyaluronan
E.Collagen Type I
Osteoid
lectins
glycoproteins from plant seeds
fluoro stained - bind to carbs at high affinity and specificity
what are these?
Macrophages: Phagocytic activity
GAGS resist….
compression
- Negatively charged GAGS attract osmotically active cations (Na)
- Water binding results in a heavily hydrated matrix strongly resisting compression
•3 Main types of cartilage (matrix composition)
- Hyaline – mostly type II collagen
- Elastic – collagen type II & elastic fibers
- Fibrocartilage – dense network type I collagen
•All types avascular.
–Nutrients derived from adjacent CT or from synovial fluid (in the case of articular cartilage)
RESOLUTION (Resolving power)
- Determines clarity and richness of detail
- Measures how close 2 objects can be and still appear separate (“the smallest distance”)
•
• Resolution of …
human eye - 200 µm
light microscope - 0.2 µm
electron microscope - 0.002 µm
CYTOKINESIS
•Cytokinesis begins by assembly of contractile ring of actin and myosin filaments dividing cell in two
•
•Cell divided into two cells, each with one nucleus
•
•Cytoplasm and organelles are divided by the constriction ring
Neutrophils
- Active phagocytes
- First leukocytes to arrive at infection
- Azurophilic primary granules
- –Myeloperoxidase-generate hypochlorite toxic to bacteria
- –Lysozyme –degrade bacterial wall
- –Defensins-disrupt cell membrane of bacteria
•Specific secondary granules
- –Collagenases
–Bacteriocidal proteins
these fibers are what kind of fibers, what kind of stain?
reticular
collagen type III
best seen with silver stains
Perichondrium
sheath of dense CT surrounding cartilage (carries blood, nerves and lymphatics)
Nucleolus Morphology
- Intensely basophilic* and spherical non-membranous structure
- Contains RNA and proteins
- One or more nucleoli
- Large in metabolically active cells
function?
monocyte
antigen-presenting
precursor to macrophages aand other mononuclear phago sys cells
what kind of filament, where found (specific)
MICROFILAMENTS IN MICROVILLI AND TERMINAL WEB
Granulopoiesis
Myeloblast→
Promyelocyte→
Myelocyte→
Metamyelocyte→
Mature granulocyte
(neutrophil, eosinophil, basophil)
Collagen Distribution in Nerves
- Epimysium – Types I (major component) & III (minor component)
- Perimysium – Types I, III & V
- Endomysium – Types I, III, IV, & V
Identify the different hematopoietic cell types in this tissue section (not smear) prepared from a bone marrow biopsy
Extra - Remember “MEG”
Megakaryocytic, Erythrocytic, Granulocytic Cells
A: schwann cell: myelinate a single axon
B: microglia: removing cellular debris via phago
C:astrocyte: maintain BBB
D: ogliodendrocyte: myelinates many N
E: sateliite cells: structural and metabolic supp for motor N
F: ependymal cells: produce csf
ULTRASTRUCTURE OF PLASMA MEMBRANE
trilaminar
Perineurium
•Specialized CT
–Surround fascicles of nerves
–Layers of flat epithelium-like cells
–Edges joined by tight junctions
•Blood nerve barrier
what kind of preparation can integral membrane proteins be visualized?
FREEZE-FRACTURE PREPARATION
what are the functions of bone?
mechanical
- –Protection of vital organs
- –Harbors bone marrow
- –Attachment site for muscles
metabolic
- –Ca+2, PO-3 reservoir
Embryonic connective tissue types
- Mesenchyme
- Mucoid connective tissue
A.Inefficient signal transmission at the neuromuscular junction
Urothelium: distribution, function
- Bladder, ureters, renal calyces
- Protection, distensibility
Osteoblasts origin
Mesenchymal
25 year old female patient presents to her primary care physician with complaints of abdominal pain, bloating, fatigue and chronic diarrhea. An intestinal biopsy sample shows blunted, flattened intestinal villi with damaged microvilli. In addition to the biopsy results, bloodwork was also done which confirmed a diagnosis of Celiac disease. Which of the following functions is lost due to the damage to the apical epithelial surface modifications in this condition?
A.Motility
B.Cell to cell adhesion
C.Vesicular transport
D.Absorption
E.Lipid secretion
Absorption
classify this:
Simple squamous epithelium
site where multiple junctional complexes are present
what are these and what are they important for?
Myofibroblasts:
Wound healing
Eosinophils
- Kill parasitic worms
- Important in inflammatory response triggered by allergies (e.g., asthma)
- Remove antibody-antigen complexes from interstitial fluid by phagocytosis
- Specific eosinophilic granules contain
–Major basic protein – 50% of total granule protein-accounts for granules acidophilia
–Eosinophilic peroxidase
Stereocilia characteristics
- Longer than microvilli
- Branched
- Immotile
- Increase surface area
- present in absorptive epithelia
Stable cells
–Cells that divide only following damage to replace the lost cells.
–e.g.: liver, kidney
An electron microscopic image is shown. Which of the following steps was used in the preparation and examination of this tissue?
A. Paraffin embedding
B. Mounting on glass slide
C. Preservation with glutaraldehyde
D. Staining with eosin and hematoxylin
E. Magnification by biconvex lens
C. Preservation with glutaraldehyde
Epimysium
•– Surrounds the muscle
–Dense irregular CT
Synapsis
- Takes place in prophase I
- Homologous chromosomes come together and tetrads are formed.
- Cross over: double stranded breaks, repair and DNA exchange.
- New gene combination produced.
- Duration of prophase I: 3 weeks in sperm; >12 years in oocyte.
Connective tissue proper contains
- Loose (areolar) connective tissue
- Dense irregular connective tissue
- Dense regular connective tissue
Chondroblast
•immature, precursor cell of cartilage (stellate-shaped, synthesizes matrix)
Red (hematopoietic) bone marrow
Pic below: bone marrow sinusoids
Neurons
•The structural and functional unit of the nervous system (both the CNS and PNS)
- Conduction of information
- Numerous long processes
- From Neuroectoderm (CNS neuron) or Neural crest (PNS neuron)
- Permanent cell
Q2. After fusion with the cellular plasma membrane in the distal axon, viral particles are generally too large to diffuse freely within the crowded cytoplasm environment. Thus, they will never reach the cell nucleus or the perinuclear areas where replication or reverse transcription usually takes place. However, recent studies have show that certain viruses, such as the herpes virus, have found a way to be transported from the axonal end towards the soma of the neurons. What would be the most likely mechanism that would allow such viruses to reach the neuronal soma?
(A)Association with actin
(B) Association with kinesin
(C)Association with microtubules
(D)Association with dynein
(E)Association with desmin
Association with dynein
metaphase spindle checkpoint
•ensures that all chromosomes will be segregated
Oligodendrocytes
Tissue preparation for Transmission Electron microscopy
Fixation: Glutaraldehyde Post fixation: Heavy metals (Osmium tetroxide) –> imparts electron density and better visibility Embedding: Epoxy resin–> Hard plastic block Ultra microtome: Diamond or glass knives - Ultra thin sections < 1µm Sections mounted on copper grids Stained with lead citrate and uranyl acetate
what controls apoptosis?
•Bcl-2 proteins on mitochondrial membrane.
Chromosomes
•23 pairs of chromosomes (22 pairs of autosomes and 1 pair of allosome)
•3 Types Skeletal Muscle Fiber Types
•3 Types
- Fast Type IIa
- Fast Type IIb
- Slow Type I
Platelets - EM
- Glycocalyx
- Marginal bundle
- Open canalicular system
- Dense tubular system
- Alpha granules
- Dense (delta) granules
Pia mater
•Flattened, mesenchymally derived cells closely applied to the entire surface of the CNS tissue.
Color of brown fat
–Abundant mitochondria containing cytochrome pigment
–Large number of capillaries
PNS
- Neuron body (Ganglion)
- Axons (Nerve)
A student in the histology lab is describing a tubular structure whose lumen is lined by two layers of stacked cells that all have similar height and width. What type of epithelium is this student describing?
A.Simple squamous epithelium
B.Pseudostratified columnar epithelium
C.Stratified cuboidal epithelium
D.Stratified squamous non-keratinized epithelium
E.Urothelium
A.Stratified cuboidal epithelium
staining? what is it?
Platelets – LM
- In stained blood smears often in clumps
- Platelets are discoid in shape
- Very light peripheral zone (hyalomere) and darker central zone containing granules (granulomere)
what kind of m is this?
smooth
CELL-CYCLE CONTROL SYSTEM DEPENDS
Controlled by cyclins and cyclin dependent kinases (CDK)
leptin
prod by adipocytes in proportion to body fat
- Binds to receptors in hypothalamus
- Acts to ↓food intake, ↑ energy expenditure, and ↓ fat stores
- Most obese humans produce adequate leptin, but target cells not responsive
what are these?
Adult stem cells such as pericytes
Dura mater
- Dense irregular connective tissue
- Organized as an outer periosteal layer and an inner meningeal layer.
Uses of Crysection
onco-sx, histochemical study
Reticular fibers form….
a delicate stromal network in cellular organs - lymphoid and hematopoietic organs, endocrine glands, and liver
synapse
Specialized connective tissue:
Lymphatic tissue
collagen fibrils at higher magnification
typical 67-nm banding pattern
Microscopic examination can provide a surgeon in the operating room with valuable information regarding the extent of neoplastic tumor resection by evaluating the margins of the surgical incision for the presence or absence of tumor cells. What would be the most suitable tissue-processing technique for this type of intraoperative examination?
(A)Fresh tissue examination followed by paraffin embedding, sectioning, and staining
(B)Fast formaldehyde fixation followed by paraffin embedding, sectioning and staining
(C)Rapid freezing of a fresh specimen followed by sectioning and staining
(D)Glutaraldehyde fixation followed by epoxy resin embedding, sectioning, and staining
(E)Frozen-fracute preparation followed by sectioning and staining
Rapid freezing of a fresh specimen followed by sectioning and staining
monocytes
•Precurser cells of macrophages, osteoclasts, microglia, and other cells of the mononuclear phagocyte system
–In tissues macrophage-type cells function as phagocytes and antigen presenting cells
Schwann Cells (Neurolemmocytes)
- Surrounds and insulates PNS axons
- Allows for faster action potential propagation (saltatory conduction; one node of Ranvier to the next).
- Increases conduction velocity of action potentials.
- Promote axonal regeneration
- Derived from Neural Crest
- One cell per axonal segment
- Nuclei: oval to elongated nuclei in the cell peripher
KINETOCHORE
PROTEIN STRUCTURE TIGHTLY ASSOCIATED WITH CENTROMERE DNA, WHERE THE SPINDLE FIBERS ATTACH DURING CELL DIVISION
A.1)RBC, 2)platelet, 3)lymphocyte, 4)neutrophil, 5)basophil
GFAP
GFAP (Glial fibrillary acidic protein) antibody - Astrocyte Marker
what is this picture showing predominantly?
(A)Nucleolus
(B)Nuclear Pores
(C)Ribosomes
(D)DNA
(E)Vacuoles
Nuclear Pores
Diffusion of nutrients in bone is facilitated by which of the following?
A.Active transport systems
B.Bone matrix
C.Periosteum
D.Gap junctions
E.Hemidesmosomes
A.Gap junctions
vescile traficing through endosomeal compartment is directly largely via
rab proteins
peripheral memebrane G groteins0
Connective tissue is derived from embryonic
mesenchyme
Cerebral Cortex
- Six recognizable layers of neurons with different sizes and shapes.
- Efferent pyramidal neurons being the most prominent cells.
•
•Neurons of the cerebral cortex function in the integration of sensory information and the initiation of voluntary motor responses.
PTH
–inhibits osteoblasts and causes them to secrete osteoclast stimulating factor. Matrix is broken down and calcium delivered to interstitial fluid. (WHEN CALCIUM IS LOW)
Cryofracture/ Freeze etching
- A type of unfixed tissue preparation for electron microscopy
- Frozen section is fractured and covered by platinum vapor à Replica is examined under EM
- Use: To study the details of cellular membranes and organelles
A 28 year-old male arrives to the emergency room in a comatose state. The patient is known for drugs and alcohol abuse, which require an increased level of detoxifying enzymes in the liver.
What is the major intracellular organelle in hepatic cells that undergoes extensive proliferation in these patients?
(A) Smooth endoplasmic reticulum (sER)
(B) Rough endoplasmic reticulum (rER)
(C) Mitochondria
(D) Lysosomes
(E) Golgi Apparatus
(A)Smooth endoplasmic reticulum (sER)
Microvilli Glycocalyx = Brush border
The ground substance ….
mainly a complex mixture of three classes of macromolecules
- •Glycosaminoglycans (GAGS)
- •Proteoglycans
- •Multiadhesive glycoproteins
most lost during tissue processing
White adipose tissue – unilocular adipocytes
ELECTRON MICROSCOPY
- Based on the interaction of electrons with the tissue components.
- Electron beam has shorter wavelength than light = acheive higher resolution.
pattern?
‘honeycomb’ or ‘fried egg’ pattern of oligodendrogliomas
IN SITU HYBRIDIZATION (ISH)
- Technique that is used to localize a specific gene or to identify cells with a specific DNA sequence or mRNA.
- Nucleic acid sequences (probes) applied to tissue sectionsà hybridization.
- Probes are tagged with radio-isotopes or enzyme marker.
- Target is identified by autoradiography or enzyme immunochemistry or fluorescent stains.
RIBOSOMES
LARGE AND SMALL SUBUNITS ASSEMBLE ALONG STRANDS OF mRNA TO FORM POLYRIBOSOMES
- Ts
what is this a pic of?
Macrophage engulfing red blood cells
Osteoclasts
Highly variable structure and physical/mechanical properties of connective tissue (7)
- Physical support
- Metabolic support
- Defense
- Repair
- Energy reserve
- Temperature regulation
- Storage
Collagen fibrils (visible only on EM) bundle together to form collagen fibers (visible on LM)
•Congenital cataracts
- Gap junction defect partly responsible for the condition
- Cx 50 expressed in the lens
- Degree of opacity in the lens varies by patient
- Can lead to blindness
- Autosomal dominant inheritance pattern
Tissue preparation process
- fixation 2. dehydration 3. clearing 4. infiltration 5. embedding 6. trimming
collagen banding results from…
staggered arrangement of collagen molecules that form the fibril
While flexing your bicep at the gym trying to intimidate your arch nemesis you accidently pop your biceps tendon giving you “Popeye’s” Deformity. You go to Dr. Bruno and he relays to you that not only did you severely damage your tendon, but your biceps muscle is completely shot. In this moment you remember Dr. Vidal’s lecture on muscle and proclaim how skeletal muscle, like the biceps, has what kind of regenerative capabilities?
A. Just start calling you Popeye cause skeletal muscle has no regenerative capability
B. Skeletal muscle has this thing called a “Satellite cell” that has a little bit of regenerative capability
C. Skeletal muscle has this thing called a sarcomere that allows you to regenerate the muscle
D. Smooth muscle is the ONLY kind of muscle that has any kind of regenerative abilities
E. I plead the 5th.
function of squamous epithelium
- Facilitates viscera movement (mesothelium)
- Active transport by pinocytosis (mesothelium & endothelium)
- Secretion of biologically active molecules (mesothelium)
what are Glandular epithelia
- Cells specialized to secrete
- Glands can be unicellular or multicellular
- goblet cells are an example of unicellular gland
Calcium Mobilization
- Mainly resorbed from spongy bone.
- 2 hormones regulate calcium release and absorption:
–PTH
–Calcitonin
A mother brings her 8 year-old boy to your office with the complaint of recurrent respiratory infections. The boy is later diagnosed with a genetic disorder that interferes with the motility of the cilia. Which of the following structures are responsible for the ciliary motility?
(A)Actin filaments
(B)Microtubules
(C)Lamins
(D)Myosin filaments
(E)Desmins
Microtubules
Development of hematopoietic tissue
- Early embryo – yolk sac
- Second trimester – liver and spleen
- Third trimester – bone marrow
Fibrocartilage
Erythrocytes
- Most abundant formed element
- Densely filled with hemoglobin - specialized to transport oxygen and carbon dioxide
- Rely on anaerobic glycolysis
- Lack nuclei - cannot replace defective protein
- Average lifespan 120 days
Which of the following microscopy uses the principle of optical sectioning of different planes of the tissue to get high quality 3-D image?
A. Polarizing microscopy
B. Transmission electron microscopy
C. Compound light microscopy
D. Confocal microscopy
E. Dark field microscopy
Confocal microscopy
Astrocytes
- Morphologically heterogeneous cells that provide physical and metabolic support for neurons of the CNS (repair, K+ metabolism, removal of excess neurotransmitter, maintenance of the blood-brain barrier)
- Largest glial cell
- Derived from Neuroectoderm
- Nuclei: salt and pepper pattern
- Reactive gliosis happens in response to injury
- Intermediate filament = GFAP
Brown adipocytes produce
heat by
nonshivering thermogenesis
- Hibernating animals
- Newborn humans
Glycosaminoglycans (GAGs)
long unbranched polysaccharides composed of repeating disaccharide units (hexosamines and uronic acids)
this is what disease?
Celiac’s Disease
•H&E stain: irregular, potato-shaped nuclei and numerous fine cellular processes
astrocyte
what 2 things (white patches) is this showing?
golgi, lysosomes
microtome
Sectioning of the blocks of tissue: thin sections (5 to 10µm thick) Steel knives are used
The cell division of mouse embryo was being studied in a research lab. The dividing cells were observed to be mostly in which of the following stages of cell cycle?
A.S phase
B.G2 phase
C.M phase
D.G1 phase
E.G0 phase
M phase
Origin of platelets
- Platelet demarcation membranes partition megakaryocyte cytoplasm into individual platelets
- Megakaryocytes extend long processes called proplatelets into lumen of sinusoids
- Platelets separate from the ends of proplatelet cytoplasmic processes
ANAPHASE
Chromatids pulled to opposite spindle poles -separation
- Kinetochore tubules shorten
- chromosome segregation
Spindle poles move apart
what cells are the arrows on superior part showing
Chondrocytes
caveolae
receptor-medicated endocytosis in endothelial cells
(little caves)
caveolin
thermogenin
Uncoupling protein (UCP-1)
- Mitochondrial inner membrane has ↑thermogenin
- Permits backflow of protons from intermembranous space without passing thru ATP-synthetase
Common myeloid and lymphoid stem cells
to multiple lineage-restricted myeloid/lymphoid progenitor cells
what are these? where?
NISSL SUBSTANCE:
ABUNDANT POLYRIBOSOMES IN NEURON
Neuronal Classification
•Multipolar neuron: most abundant.
- One axon and two or more dendrites.
- Presence of dendritic arbor (very branched dendritic processes). Common in motor neuron.
•Bipolar neuron: rare.
- One dendrite and one axon
- Special sensory system (e.g. sensory neurons: retina, olfactory mucosa, inner ear)
•Unipolar or pseudounipolar: Spinal ganglia.
- Since process that bifurcates near cell body (longer branch goes to the periphery and the other to the CNS)
During the investigation of her pathological condition, a 55 year old woman undergoes a kidney biopsy that is later examined by electron microscopy. The nucleus of an endothelial cell exhibits a peripheral ring of dark-stained chromatin (arrow, shown in the image). Which of the following best describes the functional significance of the dark-stained ring of marginal chromatin observed in this electron micrograph?
(A)Ribosomal RNA biosynthesis
(B)Organization of inactive chromatin
(C)DNA replication center
(D)Nucleosome assembly
(E)Kinetochore complex assembly
Organization of inactive chromatin.
Largest membrane bound organelle?
Nucleus
cross-links of collagen characteristics and function
•Extracellular lysine oxidase covalently cross-links lysine in collagen molecules of adjacent rows
- tensile strength
columnar epithelium function
•Protection, lubrication, absorption, secretion
a) Renal collecting duct, (b) Oviduct, ( c) Gallbladder
Osteogenesis
1.Intramembranous Ossification
- Mesenchyme à Osteoblasts à Osteoid
- Flat bone formation
2.Endochondral Ossification
- Hyaline cartilage mold replaced by bone matrix
- Long bone formation
Arachnoid
- Sheet of connective tissue in contact with the dura mater
- A system of loosely arranged trabeculae composed of collagen and fibroblasts, continuous with the underlying pia mater layer
Muscle Contraction
1) ACh released at NMJ
2) ACh binds to receptors on sarcolemma
3) Depolarizing wave spreads via T-tubules
4) Depolarization opens Ca+2 channels in SR
5) Ca+2 enters the sarcoplasm
6) Ca+2 binds to TnC
7) Myosin binds to actin
8) Myosin head pivots, slides actin towards A band
9) ATP binds to myosin head
10) Myosin detaches, pivots, reattaches to actin and pivots actin forward
11) Contraction ends when Ca+2 exits sarcoplasm
restriction point in cell-cycle
G1/S - just before S
Gene coding retinoblastoma gene controls the restriction point
Ex of basic dyes
Hematoxylin, methylene blue
Celiac disease
- Loss of the microvilli brush border of the absorptive cells
- Immune reaction against the wheat protein gluten during its digestion
where are elastic fibers deposited in?
Amorphous elastin is deposited in a scaffold of fibrillin microfibrils
Recticulocytes
Wright stain
Supravital stain : new methylene blue
Neurons consist of:
- A cell body (or soma or perikaryon). Contains the nucleus, Nissl bodies, and other organelles, The trophic center of the neuron.
- Several dendrites. Shorter processes that transmit impulses toward the cell body. Receive stimulus at sinapses.
- An axon. Usually the longest process of the cell body(ends in telodendria). Transmits impulses away from the cell body. Generate and conduct impulse to other cells. (May receive stimulus)
In order of development, what are the 6 cell types of erythropoiesis?
a. Proerythroblast, basophilic erythroblast, polychromatophilic erythroblast, orthochromatophilic erythroblast, reticulocyte, erythrocyte
b. Erythroblast, basophilic erythroblast, polychromatophilic erythroblast, orthochromatophilic erythroblast, reticulocyte, erythrocyte
c. Proerythroblast, orthochromatophilic erythroblast, basophilic erythroblast, polychromatophilic erythroblast, reticulocyte, erythrocyte
d. Proerythroblast, polychromatophilic erythroblast, basophilic erythroblast, orthochromatophilic erythroblast, reticulocyte, erythrocyte
a.Proerythroblast, basophilic erythroblast, polychromatophilic erythroblast, orthochromatophilic erythroblast, reticulocyte, erythrocyte
Specialized connective tissue:
Elastic tissue
•Nuclear lamina
–Lamin (Intermediate filament)
–Stabilizes the envelope by interacting with nuc envelope and chromatin
Craniofacial mesenchyme derives
from neural crest (ectomesenchyme)
Proteasomes
PROTEASE COMPLEXES THAT DEGRADE WITHOUT LYSOSOMES
targets ubiquitin-ated cells
top arrow points to…
zonula occludens, apical end
structure: actin
function: seals adjacent cells
what are the arrows indicating
EM OF NUCLEAR ENVELOPE SHOWING NUCLEAR PORES
More than just an envelope to the cell, the cell membrane or plasmalemma carries out many functions that are fundamental to the survival of the cell and ultimately the organism. Which of the following features is not characteristic of a cell’s plasma membrane?
(A)Allows the lateral movement of proteins across its surface
(B)Cell-to-cell recognition
(C)Membrane proteins are linked to the cytoskeleton
(D)Energy synthesis via oxidative phosphorylation
(E)Allows passive diffusion of certain molecules
(A)Energy synthesis via oxidative phosphorylation
function?
adaptive immunity
B, T, NK - dependent of CD markers
intermediate filaments
microtubules
actin
Basic dyes
stain basophilic (acidic/anionic) structures (DNA, RNA, glycosaminoglycans).
LysosomAL ENZYMES
what type of cartilage is this?
Hyaline Cartilage
phospholipids
AMPHIPATHIC (BOTH HYDROPHILIC AND HYDROPHOBIC) ARRANGED MOLECULES IN A LIPID BILAYER
Precurser cells
Each progenitor cell/CFU
gives rise to a series of morphologically recognizable precurser cells that gradually assume the characteristics of the mature functional cell types
Skeletal M type IIb
fast type: glycolytic
–Rapid, short term contractions
–Anaerobic metabolism, few mitochondria
–Rapid to fatigue
–Paler appearance than Type I
Nucleoporins
- proteins that help form a ring structure with 8-fold symmetry encircling a central pore
- Regulate transport of macromolecules in both directions
what stain and what id?
Romanovsky stains (Examples-Wright, Giemsa): Identify blood and bone marrow cells on smears
Regenerative Capabilities of cardiac M
•No satellite cells, virtually no capability for regeneration
–Heart attacks – fibroblasts, scar formation
Blood clot containing platelet aggregates, fibrin network, and entrapped RBCs
Why do mitochondria stain pink when using H&E?
(A)Because they are Acidic (Basophilic)
(B)Basic they are Basic (Acidophilic)
(C)Because they are Large
(D)Because they are Small
(E)Because they are dying
Basic they are Basic (Acidophilic))
what is the result of protein aggregates in ground substance of cartilage/
pressure or turgor
accounts for ability to resist compression without inhibiting flexibility
cartilage excellent shock absorber
A.Interstitial growth
Brown adipose tissue
- Maximal at birth (newborn 2%-5% of body weight)
- Greatly reduced in adult
Chondrocyte
•main cell of cartilage
–Essentially a chondroblast trapped in its matrix
clathrin
invag of pits
peripheral memb protein
Satellite Cells
- Structural and metabolic support for neuronal cell bodies
- Electrically insulates PNS cell bodies
- Found in peripheral ganglia
- Derive from Neural Crest
- Around the cell body of PNS neuron
- Indistinct cell boundaries
- Nuclei: Small, round and condensed
•
Arachnoid villi
- Outpocketings of arachnoid away from the brain
- Penetrate the dura mater and enter blood-filled venous sinuses.
- Function in releasing excess CSF into the blood.
Fluorescence microscopy
- Ultraviolet light is used.
- Fluorescent stains (only fluorescent molecules are visible)
- Fluorescent stain absorbs UV rays and emit light of longer wavelength than the visible range
- Much more specific than routine stains
Slide preparation
Section is mounted on the glass slide
Deparaffinized
Stained to enable visual differentiation of various cellular components
Covered and protected with coverslip
Examined under light microscope
structure and function?
•Found only in females
- Inactivated X chromosome (one of two)
- Random inactivation – Lyonization
•Seen as a dense heterochromatin
- Due to chemical modification of chromatin
•Clinical: Gender determination
Dense irregular connective tissue
Functions of blood:
•Transport
–Nutrients, wastes, O₂, CO₂, hormones, cells
•Physiologic homeostasis
–Participates in heat distribution
–Assists in regulation of body temperature
–Assists in maintenance of osmotic balance
–Assists in maintenance of acid-base balance
•Defense
–Circulation of inflammatory cells, immune cells, and complement
–Circulation of coagulation factors and platelets
Lymphocytes
lymphocyte
- Central role in immunity
- Major classes include B-lymphocytes, T-lymphocytes, and natural killer cells
- Subdivided into functional groups by CD markers
Osteomalacia
- Can be the result of insufficient calcium intake in the diet
- Also caused by hypovitaminosis D
- Osteoid is deposited but is either demineralized or unmineralized
b
excit neuroT
ACh, Glutamate, Serotonin (5-HT)
Biconcave shape of RBCs:
helps maximize surface-to-volume ratio facilitating oxygen exchange
A spectrin lattice anchored to the membrane by ankyrin helps support the biconcave shape and flexibility of the erythrocyte membrane
The apical surface of the cells shown here have glycocalyx. Which of the following special stains is used to stain this structure?
A. Sudan black
B. Oil Red O
C. PAS stain
D. Silver stain
E. Trichrome stain
C. PAS stain
PATHWAYS OF LYSOSOMAL ACTIVITY
- Autophagy - fusion with autophagosomes
- Heterophagy - fusion with heterophagosomes
- Extracellular secretion of hydrolytic enzymes
columnar epithelium distribution
•Intestines, gallbladder
a) Renal collecting duct, (b) Oviduct, ( c) Gallbladder
ependymal cells;
- Columnar cells that line the ventricles of the brain and the central canal of the spinal cord.
- Epithelial-like cells
- Derive from Neuroectoderm
- Single layer of cuboidal-to-columnar cells
- Clear cytoplasm, rounded nuclei
- Has both Microvilli and Cilia as its apical specializations
squamous keratinized epithelium: distribution and function
epidermis
protection, prevent h20 loss
what is arrow pointing to?
terminal web, where there are microvilla with microfilaments (actin) inside
this is a pic of….
Quiescent fibroblast
A 2 year old boy is brought to his pediatrician. The mother suspects her son is having vision problems. An examination detects the presence of cataracts in both eyes. The condition is later determined to be congenital, the result of a defect in the gene encoding for the Connexon 50 (Cx50) protein. Given this information, which cell junction is defective in this patient?
A.Tight Junctions
B.Gap Junctions
C.Adherent Junctions
D.Desmosomes
E.Hemidesmosomes
A.Gap Junctions
MICROTUBULE NETWORK ORIGINATING FROM MICROTUBULE ORGANIZING CENTER/CENTROSOME
It performs functions similar to the mast cell
Most mesenchyme derives from
embryonic mesoderm
Ganglia
Brown fat:
Ultrastructure
Pseudostratified columnar epithelium Distribution
•Lining of trachea, bronchi, nasal cavity
what do silver grains do?
particles that incidcated cells/region of cells where specific macrocol were synth prior to fixation
used in audioradiography
axon / dendrite
Diagram of events involving leukocytes in a postcapillary venule at sites of inflammation.
1. Local macrophages activated by bacteria or tissue damage release
- proinflammatory cytokines such as interleukin-1 (IL-1)
- tumor necrosis factor-α (TNF-α)
- signal endothelial cells of nearby postcapillary venules to rapidly insert glycoprotein selectins on the luminal cell surfaces.
- Passing neutrophils with appropriate cell surface glycoproteins bind selectins
* cells to adhere loosely to the endothelium and “roll” slowly along its surface. - Exposure to these and other cytokines causes
- expression of new integrins on the rolling leukocytes and
- expression of the integrin ligand ICAM-1 (intercellular adhesion molecule-1) on the endothelial cells.
Junctional complexes between the endothelial cells are selectively downregulated, loosening these cells.
- Integrins and their ligands provide firm endothelial adhesion of neutrophils to the endothelium, allowing the leukocytes to receive further stimulation from the local cytokines.
- Neutrophils become motile, probe the endothelium with pseudopodia, and, being attracted by other local injury-related factors called chemokines, finally migrate by diapedesis between the loosened cells of the venule.
- Rapid transendothelial migration of neutrophils may be facilitated by the cells’ thin, segmented nuclei.
- All leukocytes first become functional in the ECM after emerging from the circulation by this process.
Nissl bodies can be found in __________ but not in ________.
•Nissl bodies can be found in dendrites but not in axons.
What color does the nucleus stain when using H&E?
(A) Brown
(B) Pink
(C) Red
(D) Purple
(E) Silver
Purple
structure and filament association
microtubules in cilium, basal body
kinesins: carry materials away from MTOC (microtub org center), towards plus end, away from nuc
dyneins: carry materials to MTOC (microtub org center), towards negative end, towards from nuc
A
Multipotent cells
Able to differentiate to limited types of cells; Ex- hematopoietic stem cells.
Glial Cells
- Support and protection of the neurons
- Other neural actives (e.g. nutrition, defense)
- Short processes
Fibrocartilage
- Intermediate between dense CT and hyaline.
- Found in intervertebral discs and some ligaments
- Type I collagen fiber bundles.
collagen family
•Fibrillar collagens – I, II, III
–Type I – skin, tendon, ligament
–Type II - cartilage
–Type III – reticular fibers
•Sheet-forming collagens – IV
–Basal and external lamina
•Linking/anchoring collagens – VII
–Secures basal lamina to ECM
these are? function?
Mast cells contain basophilic granules that store mediators of inflammation (histamine, heparin, eosinophilic chemotactic factor)
Reticular fibers are produced….
produced and partly covered by modified fibroblasts called reticular cells
stereocilia
Loose connective tissue:
mesentary
Dehydration
Water replaced by alcohol
•Criteria for Differentiating Skeletal Muscle Fiber Types
–Rate of contraction
–Mechanism of ATP generation
Thrombopoiesis
Megakaryoblast→
Promegakaryocyte→
Megakaryocyte→
Platelets
SER function
Steroid hormone synthesis (adrenal cortex)
Drug detoxification (liver)
Muscle contraction (skeletal muscle)
Blood-Brain Barrier
Prevents circulating blood substances (eg, bacteria, drugs) from reaching the CSF/CNS.
Functional barrier that allows much tighter control than that in most tissues over the passage of substances moving from blood into the CNS tissue
MICROSCOPIC AUTORADIOGRAPHY
A method of localizing newly synthesized macromolecules (DNA, RNA, protein, glycoproteins) in cellular structures
particles called silver grains indicate the cells or regions of cells in which specific macromolecules were synthesized just prior to fixation
what are the most abundant connective tissue fiber in human body?
Collagen fibers – 30% of dry weight
structure and its function
Peroxisomes:
OXIDATIVE REACTIONS GENERATING H₂O₂
Labile cells
Continuously dividing cells
bone marrow, epidermis, gastrointestinal lining
these fibers *(what are they) found in what kinds of tissues, location?
in tissues that stretch or expand and return to original shape: arterial walls, lung, vertebral ligaments
Trichrome staining
•Collagen: Mallory stain, Masson stain
fluorescein-phalloidin
fluro stain for actin filaments
types of glandular epithelium
pinocytosis
dimples, pinches off in (like a pimple into the cell)
cell drinking
cuboidal epithelium function
cover, secretion
a) Renal collecting tubules, (b) thyroid cells, ( c ) Ovarian mesothelium
Dense regular connective tissue
Glycocalyx
•glycolipids/surface proteins contain oligosaccharides important for:
–Protection and immunity
–Cell-cell adhesion
–Signaling molecules
Which of the following are not membrane-bound cytoplasmic structures?
(A)Mitochondria
(B)Glycogen granules
(C)Peroxisomes
(D)Lysosomes
(E)Secretory vesicles
(A)Glycogen granules
Matrix Calcification
- Osteocalcin secreted by osteoblasts binds Ca2+ and increases [Ca2+]
- Osteoblasts also secrete alkaline phosphatase increasing [PO-4]
- The vesicles housing alkaline phosphatase serve as the foci for the formation of hydroxyapatite crystals. (1st step in calcification, unique to bone, no other collagen-containing tissue contains it)
- This process continues until collagen is embedded in calcified material.
Allosomes
•Sex chromosomes; XX in females and XY in males
squamous epithelium distribution
•Lining of vessels (endothelium)
Serous lining of cavities: pericardium, pleura, peritoneum (mesothelium
Oligodendrocytes
Dark-field microscopy
Special condenser with a shield in the center.
Unstained & transparent material.
Objects that deflect light are seen in a dark background
Which of the following proteins contributes to the structural matrix that anchors chromatin to the nuclear membrane during interphase of the cell cycle?
(A) Desmin
(B) Lamin
(C) Keratin
(D) Vimentin
(E) Perlecan
Lamin
INTERPHASE
- Cell increases in size
- DNA of chromosomes is replicated
- Centrosome is duplicated
Types of chromatin
Euchromatin
- Lightly basophilic stained.
- Fine granular.
- Uncoiled DNA.
- Regions of active transcription.
- More in metabolically active cells
Heterochromatin
- Intensely basophilic.
- Coarse electron dense.
- Tightly coiled DNA
- inactive.
- Accumulate near the nuclear lamina.
d
Collagen makes-up —- all proteins in peripheral nervous tissue
49%
type 1 most abundant
–Epineurium – Approximately a 1:1 ratio of type I and type III
–Perineurium – Types III, & IV
–Endoneurium – Mostly type III & IV though Type I also present in small quantity
3 structures of BBB
- Tight junctions between nonfenestrated capillary endothelial cells
- Basement membrane
- Astrocyte foot processes
- The phagocytes of the CNS (protective, phagocytic and immune-related function)
- Scavenger cells of the CNS (respond to tissue damage by differentiating into large phagocytic cell)
- Derive from Mesoderm
- Part of the mononuclear phagocyte system
•
- Nissl stain: Not readily seen
- Nucleus: Small and flat
Cerebral Cortex
Proteoglycans func:
bind and sequester growth factors
Release of growth factors during tissue repair stimulates new cell growth and ECM synthesis
The granules contain major basic protein
Fixation
Preserves and hardens by cross- linking proteins (Formaldehyde)
IMMUNOHISTOCHEMISTRY
- Technique used for identifying a specific macromolecule (antigens) by means of antigen-antibody interactions.
- Types: Direct and indirect
- Indirect: More sensitive; Used in pathology
- Use: Proteins specific for pathological condition used to diagnose the disease
Q3. A 28 year-old male arrives to the emergency room in a comatose state. The patient is known for drugs and alcohol abuse, which require an increased level of detoxifying enzymes in the liver.
What is the major intracellular organelle in hepatic cells that undergoes extensive proliferation in these patients?
(A) Smooth endoplasmic reticulum (sER)
(B) Rough endoplasmic reticulum (rER)
(C) Mitochondria
(D) Lysosomes
(E) Golgi Apparatus
(A)Smooth endoplasmic reticulum (sER)
PROPHASE
- Duplicated chromosomes condense
- Mitotic spindle between two centrosomes
- Centrosomes begin moving apart
Achantolysis
loss of intercellular connection
mammary gland
Apocrine Secretion
Intramembranous Ossification
Pseudostratified columnar epithelium Function
- Protection
- Secretion
- Cilia-mediated transport
squamous nonkeratinized: distribution and function
mouth, espophagus, largynx, vagina, anal canal
protection, secretion, prevent water loss
