PRELIM HISTO REVIEWER

HISTOLOGY

The study of the main components of body tissues Ï How it is arranged to constitute the organ Ï How the cells are structured specific to its organ Ï A tissue is composed of cells and ECM

Cell Extracellular Matrix

2 TISSUE COMPONENTS

cell

basic fundamental unit of any living organism

EXTRACELLULAR MATRIX

composed of macromolecules, it supports the cell

EXTRACELLULAR MATRIX

Ë secreted by cells and surrounds them in tissue

EXTRACELLULAR MATRIX

Ë consist of many kind of macromolecules which form collagen fibrils and basement membranes

Fixation Dehydration Clearing Infiltration Embedding Trimming

PREPARATION OF TISSUES UNDER LIGHT MICROSCOPE

Fixation

small pieces of tissue are placed in solutions of chemicals that pre-serve by cross-linking proteins and inactivating degradative enzymes (formalin)

Dehydration

the tissue is transferred through a series of increasingly concen-trated alcohol solutions, ending in 100%, which removes all water

Clearing

Alcohol is removed in toluene or other agents in which both alcohol and paraffin are miscible

Infiltration

The tissue is then placed in melted paraffin until it becomes completely infiltrated with this substance

Embedding

The paraffin-infiltrated tissue is placed is placed in a small mold with melted paraffin and allowed to harden

Trimming

The resulting paraffin block is trimmed to expose the tissue for sectioning (slicing) on a microtome

Microtome

a device used to make very thin slices of tissue for histology

staining

process of coloring the microbe with a dye that emphasizes certain structures

a anionic b basophilic

Cell components such as nucleic acids with a net negative charge _____a_____ stain more readily with basic dyes and are termed _____b_____

a cationic b acidophilic

_____a_____ components, such as proteins with many ionized amino groups, have affinity for acidic dyes and are termed _____b_____

acidophilic

acid-loving, positively charged, these tissues stain with acid dye, membranes, proteins, cytoskeleton

basophilic

basic-loving, can be stained with basic dyes

catanionic

positively charged

anionic

negatively charged

toluidine blue, alcian blue, methylene blue and Hematoxylin

basic dyes examples

eosin, orange G, and acid fuchsin

Acidic dyes examples

Bright-Field Microscopy

the method most commonly used by both students andpathologists,usesordinarylightandthecolorsareimpartedbytissuestaining

condenser

collects and focuses a cone of light that illuminates the object to be observed

objective lens

enlarges and projects the image of the object in the direction of the eyepiece

eyepiece or ocular lens

further magnifies this image and projects it onto the viewer'sretinaoracharge-coupleddevice(CCD)highlysensitivetolowlightlevels with a monitor and camera

Total magnification

objective x ocular lens

Resolving power

defined as the smallest distance between two particles at which they can be seen as separate objects

FluorescenceMicroscopy

usesultravioletlight,underwhichonlyfluorescent molecules are visible, allowing localization of fluorescent probes which can be much more specific than routine stains

Phase-Contrast Microscopy

uses the differences in refractive index of var-ious natural cell and tissue components to produce an image without staining, allowing observation of living cells

Confocal microscopy

involves scanning the specimen at successive focal planes with a focused light beam, often from a laser, and produces a 3D recon-struction from the images

Polarizing Microscopy

allows the recognition of stained or unstained struc-tures made of highly organized subunitsWhen normal light passes through a polarizing filter, it exits vibrating in only one direction

Electron Microscopy

With wavelengths much shorter than those of light, electron beams allow very-high-resolution images at high magnification, called ultrastructural images

• Transmission Electron Microscopy • Scanning Electron Microscopy

2 types of electron microscopy

Transmission Electron Microscopy

is an imaging system that permits resolutionaround3nmThishighresolutionallowsmagnificationsofupto400,000 times to be viewed in detail • Electrons transmit

400,000

The transmission electron microscope (TEM) is an imaging system that permits resolution around 3 nmThis high resolution allows magnifications of up to _________ times to be viewed in detail • Electrons transmit

Scanning electron microscopy (SEM)

provides a high resolution view of the surfacesofcells,tissues,andorgansItscansanelectronbeamacrossaspecimen coated with a thin layer of heavy metal’reflected and secondary electrons from the specimen are processed into a 3D ultrastructural image

BLASTOMERES

• The first zygotic cellular divisions produce cells called

EMBRYONICSTEMCELLS

•Explantedtotissueculturecellsoftheinnercall mass are called

CELL/PLASMA MEMBRANE OR PLASMALEMMA

made of phospholipids, cholesterol, proteins, and oligosaccharide chains covalently linked to phospholipid and protein molecules’ selective barrier

CELL/PLASMA MEMBRANE OR PLASMALEMMA

- consist of bilayer of phospholipid molecules which are amphipathic

hydrophilic head and hydrophobic tail

What are the two parts of a phos-pholipid?

Hydrophilic

- polar, _____?_____ head

hydrophobic

- non polar, _____?_____ tail

polar

hydrophilic head is ??

non-polar

hydrophobic tail is ??

Proteins

are major constituent of cell membrane

Intrinsic or Integral proteins

incorporated with the lipid layer, found in the cell membrane (inside/within "proteins within the cell membrane")

Transmembrane proteins

are integral proteins that completely expands to the bilayer

Peripheralproteins

itcanbeseenperipherally,foundatinternalpartorinside the cell membrane

•Transmembrane proteins •Extrinsic or Peripheral proteins

TYPE OF INTEGRAL PROTEIN

1 Physical barrier 2 Selective permeability 3 Electrochemical gradients 4 Cell communication

FUNCTION OF PLASMA MEMBRANE

Physical barrier

establishes a flexible boundary, protects cellular contents, and support cell structure Phospholipid bilayer separates substances inside and outside the cell

Selective permeability

- Regulates the entry and exit of ions nutrients, and waste molecules through the membrane

Electrochemical gradients

- maintains electrical charge difference across plasma membrane

Cell communication

- has receptors that respond to molecular signals (com-municate with each other within materials’ allows transfer)

• Passive processes • Active processes •Vesicular transport

TRANSPORT ACROSS PLASMA MEMBRANE

- Simple diffusion - Facilitated diffusion - osmosis

type of transport under Passive processes

active transport

type of transport under under active processes

- Exocytosis - Endocytosis - Phagocytosis - Pinocytosis - Receptor mediated phagocytosis

type of transport under vesicular transport

PASSIVE/SIMPLE DIFFUSION

- type of transport that is entirely dependent on the presence of concentration gradient

FACILITATED DIFFUSION

- involves the movement of large hydrophilic mol-ecules, requires presence of protein carrier molecules "gated pores"

OSMOSIS

- movement of water across a selectively permeable membrane’ directionisdeterminedbyrelativesoluteconcentrations’continuesuntilequilibrium is reached

ACTIVETRANSPORT

- type of transport which is independent of concentra-tion gradients, operates against extreme concentration gradients

EXOCYTOSIS

- bulk movement of substance out of the cell by fusion of secretory vesicles with the plasma membrane

ENDOCYTOSIS

- Bulk movement of substances into the cell by vesicles forming at the plasma membrane

PHAGOCYTOSIS

- type of endocytosis in which vesicles are formed as par-ticulate materials external to the cell are engulfed by pseudopodia

PINOCYTOSIS

- type of endocytosis in which vesicles are formed as intersti-tial fluid is taken up by the cell

Phagocytosis

"Cell Eating" of large particles

PINOCYTOSIS

Cell drinking’ small materials

RECEPTOR-MEDIATEDENDOCYTOSIS

-typeofendocytosisinwhichplas-ma membrane receptors first bind specific substances’

ROUGH ENDOPLASMIC RETICULUM

area where the synthesis and segre-gation of proteins for export are synthesize by ribosomes attached to it

RECEPTOR -MEDIATED ENDOCYTOSIS

receptor and bound substance then taken up by the cell

SMOOTH ENDOPLASMIC RETICULUM

Glycogen and lipid metabolism, detoxification reactions, and temporary Calcium sequestration happens here

Fatty acids and triglycerides

are mostly synthesized within the cytosol

cytosol

Fatty acids and triglycerides are mostly synthesized within the ????

Smooth Endoplasmic Reticulum

Cholesterol and phospholipid are synthe-sized in

Cholesterol and phospholipid

are synthesized in Smooth Endoplasmic Reticulum

transcription and translation

What are the 2 steps of protein synthesis?

transcription

= DNA > RNA

translation

= RNA > AMINO ACIDS/PROTEINS

DNA > RNA

what happens in transcription?

RNA > AMINO ACIDS/PROTEINS

what happens in translation?

RIBOSOMES

site of protein synthesis

RIBOSOMES

minute cytoplasmic organelles each composed of a subunit of a strand of RNA

Free ribosomes

synthesize protein for intracellular use

intracellular

Free ribosomes - synthesize protein for ________ use

Attached ribosomes

- synthesize protein for export

export

Attached ribosomes - synthesize protein for _______

Golgi complex

GOLGI APPARATUS or

Golgi apparatus

dynamic organelle’ completes the modification through packing proteins

Golgi apparatus

packaging center of the cell’ continuous with the ER

cis phase (Golgi apparatus)

receiving area of the golgi apparatus

trans phase (Golgi apparatus)

shipping area of the golgi apparatus

lysomes

digestive system of the cell

lysosome

has enzymes that can degrade a material/molecule

mitochondria

hasarraysofenzymes’responsiblefortheenergy/powerhouse of the cell’ creates ATP’ for cellular respiration

Adenosine Triphosphate (ATP)

ATP or ?

Adenosine Triphosphate (ATP)

energy currency of the cell