Bastyr ND program ISF Histology exam 1

Plasma membrane structure

Phospholipid bilayer containing cholosterol, protein, carbs

Forms selectively permeable boundary of cell

Plasma membrane function

Physical barrier

Selective permeability

Electrochemical gradient

Cell communiation

Endosome structure

made from "pinching" the plasma membrane

Endosome function

sorting of endocytosed material to be used or sent to lysosome to be broken down

Lysosome structure

Spherical sacs surrounded by a single membrane

Contains digestive enzymes

Lysosome function

breakdown of ingested substances, cell macromolecules, and damaged organelles for recycling

Rough ER structure

Extensive interconnected membrane network that varies in shape

Ribosomes attached on cytoplasmic surface

Rough ER function

Protein synthesis

Modifies, transports, stores proteins produced by attached ribosomes

Ribosome structure

Two subunits made of ribosomal RNA and proteins; can be free in cytosol or bound to ER

Ribosome function

Engage in protein synthesis

Golgi apparatus function

modifies, packages, stores, and transports lipids made by Smooth ER

Forms secretory vesicles and lysosomes

Golgi apparatus structure

Stacks of flattened membranous sacs; has polarity (cis and trans faces)

Smooth ER function

Snynthesis, transports, stores lipids

Metabolizes carbs

Detoxifies drugs, alcohol and poisons

Forms vesicles and peroxisomes

Mitochondria structure

outer membrane, folded inner membrane

Contains circular strand of DNA

Mitochondria function

ATP production

Peroxisomes structure

Membranous sacs of oxidase enzymes

Peroxisomes function

The enzymes detoxify a number of toxic substances. The most important enzyme, catalase, breaks down hydrogen peroxide.

What are the steps of tissue preparation for histo studying?

Fixation

Dehydration

Clearing

Infiltration

Embedding

Trimming

Fixation stage

small pieces of tissue placed in solutions of chemicals (formaldehyde/formalin) that preserve cell and tissue structure

Formalin/fermaldehyde preserve structures by doing what?

Cross linking and denaturing proteins, inactivating enzymes, and preventing autolysis

Dehydration phase

tissue is transferred through serious of increased alcohol solutions, ending in 100% alchohol which removes all water

Clearing phase

alcohol is removed in organic solvents (xylol) in which both alcohol and paraffin are added together

Infiltration phase

tissue placed in melted paraffin until it becomes completely infiltrated

Embedding phase

paraffin-infiltrated tissue is place in small mold with melted paraffin and allowed to harden

Trimming phase

the block is trimmed to expose tissue for slicing on a microtome

What is eosin

an acidic dye that carries a net negative charge on its colored portion

eosin reacts with

cationic groups (ex: ionized amino groups of proteins)

eosin staining is called

acidophilic

hematoxylin stains what structures and what color

stains acidic structures blue:

-DNA in cell nucleus

-RNA rich portions of cytoplasm

-Matrix of cartilage

Eosin stains what structures and what color

Stains basic structures red or pink

-Mitochondria

-Secretory granules

-Collagen

Hematoxylin reacts with what

Anionic components of cells (phosphate groups of nucleic acids)

Hematoxylin staining is called

basophilic

direct immunochemistry technique

Requires one antibody that is labeled to bind to specific protein, allowing it to be labeled and identified

Indirect immunochemistry technique

Requires two antibodies; the initial binds to the desired protein, then the second antibody, which is labeled, binds to the first and labels the protein

Immunochemistry definition

based on specific reactions between an antigen and antibodies labeled with visible markers, often fluorescent compounds or peroxidase for light microscopy and gold particles for TEM

Why is indirect immunochemistry preferred?

The added level of antibody binding amplifies the signal detected and provides greater technical flexibility

What basic cell components are non-membranous

Microtubules

Actin Filaments

Intermediate filaments

Centrioles and MTOCs

Basal bodies

What are examples of inclusions

Lipofuscin

Hemosiderin

Glycogen

Lipid

What is the glycocalyx?

cell surface coating made from glycolipids that extend outward from cell surface (found on plasma membrane)

Modified Fluid Mosaic Model suggests

membrane proteins are not bound rigidly in place and can move laterally

Lipid rafts

Collections of similar lipids with or without associated proteins that serve as attachment points for other biomolecules

integral proteins

Integral proteins that span the membrane.

Integral proteins are only extracted by

detergents that disrupt the lipids

peripheral proteins

The proteins of a membrane that are not embedded in the lipid bilayer; they are appendages loosely bound to the surface of the membrane.

Peripheral proteins can be extracted by

salt solutions

Glycosphingolipids

• sphingolipids w/ head groups composed of sugars bonded by glycosidic linkages

-not phospholipids b/c they have no phosphodiester linkage

- found on the outer surface of the plasma membrane

Plasma membrane cell surface specializations:

Junctions

Cilia

Microvilli

Glycolipids

Membrane carbohydrates that are covalently bonded to lipids.

Function of pumps in membrane

use ATP to drive thermodynamically uphill transport of ions or molecules

Function of channels in membrane

enable ions to flow rapidly through membranes at downhill direction

Function of receptors in membrane

mediate signal transduction for cellular responses to extracellular stimuli

Function of structural proteins in membrane

provide for junctions

What could happen to a person if there is a defect in the Cl- channel of their cells?

Creates dehydrated viscous mucus and leads to cystic fibrosis

Simple diffusion function

transports small, non-polar molecules directly through lipid bilayer

(lipophilic molecules diffuse quickly, water very slowly)

Carrier protein function

transmembrane proteins that bind small molecules and translocates them across membrane through conformational changes

Channel protein function

form transmembrane pores through which ions or small molecules pass selectively

Aquaporins function/def

type of channel protein that carries water through membrane

Endocytosis definition

cellular uptake of macromolecules or fluid by engulfment or invagination

Exocytosis definition

cellular secretion where cytoplasmic membrane vesicles fuse with plasma membrane and release their contents to extracellular space

Pinocytosis

smaller invagination of cell membrane which fuse and entrap extracellular fluid and its dissolved contents

Phagocytosis

ingestion of particles like bacteria or dead cell remnants

Phagocytosis process

1. Attach to membrane

2. Ingested (forms phagosome)

3. Phagosome fuses with lysosome (phagolysome)

4. Enzymes digest

5. Release

receptor-mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

Receptor-mediated endocytosis steps

1. Receptors located in clatharin coated pits

2. Receptors for specific proteins

3. LDL and receptor bind

4. Receptor and LDL complex is internalized (forms vesicle)

5. Vesicle fuses with lysozome

6. The lysozome changes pH (this change in pH causes degradation)

7. Protein is degraded to amino acids

8. Cholesterol is released into cells

9. Receptor returns to surface

Proteasome-mediated degradation