Comprehensive Histology Laboratory Practice

Comprehensive set of 194 practice flashcards testing key histological concepts, tissue types, organ microanatomy, microscope usage, and laboratory procedures covered across Labs 1 through 9.

In what orientation should the arm of the microscope be positioned relative to the user?

The microscope should have the arm pointing away from you.

Which objective lens must always be selected first when beginning to focus an image on a specimen?

Always start with the lowest objective lens.

What is the formula used to calculate total magnification on a compound light microscope?

$$\text{Total magnification} = 10\text{X ocular magnification} \times \text{magnification of objective}$$

What cleaning solution should be used to clean the body and stage of a microscope?

Use soap solution for cleaning the body and stage of the microscope.

What cleaning liquids are approved for cleaning optical microscope lenses?

Use alcohol or lens cleaner for cleaning the lenses.

Which cleaning materials are recommended for microscope lenses, and which should be used for the body and stage?

Cotton swabs, lens paper, or tissue paper for the lenses; paper towels for the body and stage.

Are students permitted to remove the eyepieces or objective lenses from the microscope?

No, do not remove the eyepiece or objectives.

What is the step-by-step procedure for cleaning microscope lenses?

Blow to remove dust, use a cotton swab or lens paper moistened with alcohol or cleaning solution in a circular motion, and dry with lens paper.

When must the $100\text{X}$ oil immersion objective lens be cleaned with cleaning solution?

Immediately after use.

Which adjustment knob should never be used once you have switched to high magnification?

Do not use the coarse adjustment knob on high magnification power; adjust using only the fine adjustment knob.

What happens to working distance as magnification increases?

The higher the magnification, the less working distance you have.

What is the primary function of the iris diaphragm within the condenser assembly?

The iris diaphragm controls the light passing through the condenser and helps in illuminating the object under observation.

What effect does closing the iris diaphragm have on specimen illumination and contrast?

Closing the iris diaphragm reduces the amount of illumination but increases the amount of contrast.

Why is it necessary to open the iris diaphragm further when changing from low power to high power?

To increase resolution.

What is the diameter of the field of view when using the $4\text{X}$ objective lens?

$4\,\text{mm}$ (or $4000\,\mu\text{m}$).

What is the diameter of the field of view when using the $10\text{X}$ objective lens?

$1.6\,\text{mm}$ (or $1600\,\mu\text{m}$).

What is the diameter of the field of view when using the $40\text{X}$ objective lens?

$0.4\,\text{mm}$ (or $400\,\mu\text{m}$).

What is the diameter of the field of view when using the $100\text{X}$ objective lens?

$0.16\,\text{mm}$ (or $160\,\mu\text{m}$).

What general relationship exists between magnification and the diameter of the field of view?

An increase in magnification causes a decrease in the diameter of the field of view.

Based on this field of view diagram, if two cells take up $1\,\text{mm}$, what is the size of one cell?

$0.5\,\text{mm} = 500\,\mu\text{m}$.

What are the typical size ranges for eukaryotic cells and prokaryotic cells?

Most eukaryotic cells have a diameter of $7\text{--}20\,\mu\text{m}$, whereas prokaryotic cells are smaller ($0.2\text{--}5\,\mu\text{m}$).

What is the average diameter of a red blood cell (RBC), making it a useful internal standard for size estimation?

$7.2\,\mu\text{m}$.

How do images appear when viewed through a light microscope, and how does stage movement affect image motion?

Images appear upside down and backwards; movement appears in the opposite direction (moving the slide to the right appears to move it to the left).

What stain is used when preparing a wet mount of cheek cells, and at what total magnification must it be verified?

Methylene blue, checked at $400\text{X}$ total magnification.

At what magnification must wet mounts of an Elodea leaf be checked by the instructor?

$400\text{X}$.

Where must cover slips be discarded at the conclusion of histology laboratory work?

In the glass disposal box.

What penalty is imposed if a student fails to properly clean up their microscope, table, and slides?

Loss of the $2$ points associated with the lab handout.

What type of simple surface epithelium with interlocking cell boundaries is demonstrated in this micrograph?

Pavement epithelium.

What single-layered, cube-shaped epithelium lining a lumen is shown in this micrograph?

Simple cuboidal epithelium.

What thin, single-layered flattened epithelium is indicated by the arrows in this tissue section?

Simple squamous epithelium (simple squamus epithelium).

What type of epithelium forms the outer parietal layer of Bowman's capsule enclosing this urinary space?

Simple squamous epithelium.

What junctional complexes appear as dense markings between adjacent simple cuboidal cells near the free surface of pancreatic ducts?

Terminal bars.

Which major glands and pigment-bearing cells are identifiable in a cross section of frog skin?

Poison glands, mucus glands, and chromatophores (located in the dermis beneath the epidermis).

What structural layer distinguishes keratinized stratified squamous epithelium from non-keratinized stratified squamous epithelium?

A cornified layer consisting of flattened, fused, anucleated cell remnants.

What specific epithelial lining is demonstrated in this H&E section of the esophagus?

Non-keratinized stratified squamous epithelium.

What multi-layered cuboidal or columnar epithelial lining is depicted in this mammary gland duct?

Stratified cuboidal (and columnar) epithelium.

In which two anatomical glandular ducts is stratified cuboidal and columnar epithelium typically found?

Mammary glands and sweat glands.

What specific respiratory epithelial lining is shown in this tracheal section?

Pseudostratified ciliated columnar epithelium.

Why is pseudostratified epithelium classified as simple rather than truly stratified?

All cells touch the basement membrane, but nuclei lie at different heights, creating the illusion of multiple layers.

Where is pseudostratified epithelium with non-motile stereocilia found?

In the epididymis.

What urinary epithelial lining characterized by rounded dome-shaped surface cells is displayed in this micrograph?

Transitional epithelium.

What is the primary function of transitional epithelium in the urinary system?

To stretch and accommodate fluctuating fluid volumes while providing an impermeable barrier against toxic urine.

What unicellular mucus-producing gland cell is indicated by the arrow among columnar epithelial cells?

A goblet cell.

What is the main function of goblet cells in mucous membranes?

To secrete lubricating and protective mucus onto the luminal surface.

What two distinct secretory cell populations are labelled in this salivary gland section?

Serous cells and mucous cells.

How do serous cells and mucous cells differ in histological appearance and staining in salivary glands?

Serous cells stain darker with round nuclei and watery protein secretions; mucous cells stain pale with flattened basal nuclei and thick mucin secretions.

Which secretory units and duct types are visible in sections of the submandibular gland?

Serous acini, mucous units, and striated ducts.

What apical membrane specialization increases the absorptive surface area of simple columnar intestinal cells?

Microvilli.

What is the layer of loose connective tissue that supports an epithelial lining in a mucous membrane called?

Lamina propria.

What embryonic connective tissue is considered the developmental precursor of all adult connective tissues?

Mesenchyme.

What primitive embryonic connective tissue is shown in this section from a pig embryo?

Mesenchyme (pig embryo).

What are the morphological characteristics of mesenchymal cells?

Star- or spindle-shaped cells with cytoplasmic processes embedded in a viscous ground substance containing sparse, fine fibers.

What loose, mesh-like connective tissue containing both collagen and elastic fibers is shown here?

Areolar tissue.

What are the two predominant protein fibers dispersed throughout areolar tissue?

Thick collagen fibers and thin elastic fibers.

What specialized connective tissue composed of lipid-storing cells with a honeycomb appearance is shown here?

Adipose tissue.

Why do adipocytes appear as empty, signet-ring-like spaces in standard H&E histology sections?

Lipids in the large central droplet are dissolved by solvents during slide preparation, leaving the nucleus flattened against the periphery.

What delicate connective tissue containing branching argyrophilic fibers forms the stroma of lymphoid organs?

Reticular tissue.

Which lymphoid organ is the only exception that lacks a framework of reticular fibers?

The thymus.

What dense regular connective tissue preparation is shown in this tendon cross section?

Dense regular - white fibrous tissue - tendon c.s.

What connective tissue type consists of densely packed, parallel bundles of collagen fibers seen in longitudinal section?

Dense regular - white fibrous tissue - tendon l.s.

What primary cell type is aligned in rows between the parallel collagen bundles in a tendon?

Fibroblasts (or tendon cells).

What connective tissue containing parallel, wavy elastic fibers is demonstrated in this ligament longitudinal section?

Dense elastic - yellow elastic tissue - ligament l.s.

What biomechanical advantage does dense elastic connective tissue provide to ligaments?

It allows tissue to stretch under tension and recoil back to its original resting length.

What connective tissue composed of randomly oriented, interwoven collagen bundles is shown in this dermis section?

Dense irregular - skin Caucasian dermis.

Why is the irregular arrangement of collagen fibers functionally beneficial in the dermis?

It provides multidirectional tensile strength against mechanical stress from various angles.

What is the principal protein fiber component in white fibrous connective tissue?

Type I collagen fibers.

How do dense regular and dense irregular connective tissues differ functionally?

Dense regular resists mechanical pull in one specific direction, whereas dense irregular resists pulling forces in multiple directions.

What organ or anatomical layer serves as the classic histological example of dense irregular connective tissue?

The dermis of the skin.

What type of collagen forms the branching fibrillar network of reticular tissue?

Type III collagen.

What mode of bone development occurs directly from mesenchymal membranes without a cartilage intermediate?

Intramembranous ossification (bone developing - intramembranous).

What type of developing bone tissue is visualized in this histological slide?

Bone developing - intramembranous.

What mode of bone formation relies on the replacement of an initial hyaline cartilage template?

Endochondral ossification (developing cartilage - endochondral).

What developmental bone process is shown transitioning from chondrocytes to ossifying bone trabeculae?

Developing cartilage - endochondral.

What concentric structural units of compact bone are shown in this ground bone cross section?

Osteons (Haversian systems).

What central channel containing blood vessels and nerves runs longitudinally through the core of an osteon?

The Haversian canal (central canal).

What are the small dark microscopic cavities that house osteocytes in ground bone called?

Lacunae.

What fine, radiating microchannels connect adjacent lacunae to each other and to the central canal?

Canaliculi.

What anatomical plane of compact bone shows longitudinally running canals and rows of flattened lacunae?

Ground bone longitudinal section.

How does a decalcified compact bone slide differ from a ground bone preparation?

Decalcified bone has its mineral matrix dissolved with acid so it can be embedded and sectioned like soft tissue, retaining osteocytes and collagen.

What are the three structural variants of cartilage found in the body?

Hyaline cartilage, elastic cartilage, and fibrocartilage.

What cartilage type characterized by a smooth, glassy, homogenous extracellular matrix is shown here?

Hyaline cartilage.

What layer of dense irregular connective tissue covers the exterior of hyaline and elastic cartilage?

The perichondrium.

What type of cartilage featuring dense networks of dark-staining elastic fibers is shown here?

Elastic cartilage.

Name two human anatomical structures composed of elastic cartilage.

The external ear (pinna) and the epiglottis.

What histological characteristics distinguish fibrocartilage from hyaline cartilage?

Fibrocartilage contains visible thick bundles of type I collagen fibers running between rows of chondrocytes in lacunae.

Does fibrocartilage possess an outer perichondrium?

No, fibrocartilage lacks a perichondrium.

What specialized mature cells reside within cartilage lacunae to maintain matrix integrity?

Chondrocytes.

What term describes clusters of chondrocytes originating from the recent mitotic division of a single parent cell?

Isogenous groups.

What are the concentric rings of calcified bone matrix surrounding an osteon's central canal termed?

Concentric lamellae.

What are the three principal muscle tissue types found in the human body?

Skeletal muscle, smooth muscle, and cardiac muscle.

What muscle tissue featuring long parallel fibers, prominent striations, and multiple peripherally placed nuclei is shown?

Skeletal muscle (H&E longitudinal cut).

Where are nuclei characteristically positioned within a skeletal muscle fiber?

Peripherally placed, immediately underneath the sarcolemma.

What delicate layer of connective tissue encloses each individual skeletal muscle fiber?

Endomysium.

What connective tissue envelope gathers multiple skeletal muscle fibers together into a fascicle?

Perimysium.

What dense fibrous connective tissue sheath wraps around an entire anatomical muscle?

Epimysium.

What contractile protein-packed structures are visible within muscle fiber profiles in this cross-sectional view?

Myofibrils.

Why do skeletal muscle fibers contain multiple nuclei?

They form during embryonic development by the fusion of many individual myoblasts into a multinucleated syncytium.

What muscular layer showing longitudinal and cross-sectionally cut smooth muscle cells with myenteric ganglion cells is shown?

Smooth muscle of the colon (muscularis externa).

What are the shape and nuclear placement of smooth muscle cells?

Spindle-shaped (fusiform) cells with a single, centrally located oval or elongated nucleus.

Does smooth muscle display sarcomeric cross-striations when viewed under light microscopy?

No, actin and myosin myofilaments are not arranged into repeating sarcomere arrays.