HISTOLOGY & CELLS Q&A + LO

IFM: i. Use antibodies tagged with fluorescent dyes to visualize specific structure ii. Allows you to see cells in action as well b. UC: i. Easy to obtain, non invasive ii. The presence of a specific cast indicates the presence of a certain disease iii. Visible under light microscope without staining

4. Describe the clinical applications of immunofluorescence microscopy and urinary casts.

Lipid bilayer membrane with hydrophilic heads facing outwards and hydrophobic fatty tails facing the center i. Also has integral and peripheral proteins to allow for the passage of molecules b. Endocytosis: i. Phagocytosis 1. Uses receptor binding to take in LARGE substances ii. Pinocytosis 1. Non-specific - no receptors 2. Takes up fluid and small molecule iii. Receptor-mediated 1. Receptors bind specific molecules c. Exocytosis i. Constitutive Secretion 1. Does not require any signaling ii. Regulated secretion 1. Requires signals binding to the receptor

Describe the plasma membrane of a cell and the processes of endocytosis and exocytosis

Mitochondrion i. Generates ATP ii. Eosinophilic b. Ribosomes i. Synthesizes protein ii. Primarily found on rER c. sER i. No ribosomes 1. Stains poorly w/ H&E ii. Makes steroid hormones & phospholipids d. rER i. Ribosomes attached to outer surface - synthesize proteins 1. Makes it basophilic ii. Highly secretory cells e. Golgi Complex i. Well developed in highly secretary cells ii. Stains weakly w/ H&E iii. Cis Golgi Network 1. Modifies proteins - packaged into vesicles iv. Trans Golgi Network 1. Modification of protein - activation 2. Sorts & packages to secretory vesicles

Describe the structure and function of a mitochondrion, ribosomes, smooth and rough endoplasmic reticulum (SER and RER), Golgi complex

Nuclear envelope i. Outer "wall" ii. Has pores to communicate w/ cytosol b. Euchromatin i. Active DNA that is loosely packed c. Heterochromatin i. Inactive DNA that is tightly packed d. Nucleolus i. Forms ribosomal RNA in secretory cells

Describe the structure of the cell nucleus and its components

Light microscopy stains tissues. Tissues are colorless - for visualization you can stain with dye. b. Electron microscopy i. Transmission EM - inside cells 1. Darker = denser ii. Scanning EM - shape/surface of cells 1. Electrons are reflected from the surface

Explain the differences between Light Microscopy and Electron Microscopy

Through various methods, endocytosis of various molecules (ex. bacteria) to form phagosome, digests the item, & then either exocytosis the remnants or keeps it as a residual body (if it isn't safe to be released)

Explain the functions of lysosomes and their related organelles

Microfilaments i. F-actin polymerized from G-actin ii. Highly dynamic iii. Maintains cell shape iv. Track for movement of myosin b. Intermediate Filaments i. Strands of fibrous proteins coiled together (d=10nm) ii. Made up of various proteins 1. Keratin in epithelial iii. High tensile strength 1. Keeps shape and anchors c. Microtubules i. Hollow tube 1. Tubulin subunits ii. Highly dynamic iii. Tracks movement for kinesins and dynein iv. Maintains cell shape v. Commonly seen in flagellum

List the types and functions of the various components of the cytoskeleton

Hematoxylin i. Basophilic - Blue/Purple ii. Basic (+) dye, attracts to (-) nucleic acids 1. Nucleic Acids: RNA, DNA, ribosomes, RER, nuclei b. Eosin i. Acidophilic/eosinophilic - Pink ii. Acidic (-) dye, attracts to (+) proteins 1. Proteins: enzymes, cytoskeleton (cytoplasm), mitochondria c. H&E i. Combine hematoxylin and eosin ii. Can view the nucleus (b/c of hematoxylin) AND the cytoplasm (b/c of eosin) d. PAS i. Used for carbs - mucus & glycogen ii. Magenta in color e. Silver nitrate i. Used for staining neurons (black color) f. Osmium-fixation i. Used for staining cell membranes (outer lining) ii. Dark blue colored membranes

Name the common histological stains, such as H&E, and describe what cellular components they stain

Fixation i. Dip in formaldehyde, 70% ethanol - stops metabolic processes ii. Intended to stop all processes and cross-link proteins - like taking a screenshot b. Embedding i. Remove water from tissue to "harden" - dehydration ii. Allows the sample to be cut c. Sectioning i. Cut/slice into thin sections d. Staining i. Dye it

Outline the main steps involved in tissue preparation for light microscopy, including fixation, embedding, sectioning, and staining