Microscope Basics and Measurements

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Questions and Answers

What is the formula to calculate total magnification in a compound microscope?

Eyepiece x Objective (correct)

Objective - Eyepiece

Eyepiece + Objective

Objective x Eyepiece

What is the function of a stage micrometer?

To provide illumination for the specimen

To increase the field of view

To calibrate the ocular micrometer (correct)

To focus the image on the lens

Which of the following factors affects the resolving power of a microscope?

Brightness of the light source

Cleaning of the lenses (correct)

Thickness of the stage

Type of specimen being viewed

When switching to a higher magnification lens, what change occurs in the field of view?

The central portion viewed becomes narrower Signup and view all the answers

What is a key characteristic of quality lenses in microscopy?

They deliver a clear image in fine detail Signup and view all the answers

How should lenses be maintained for optimal performance?

Cleaned regularly with lens paper Signup and view all the answers

What measurement unit is typically used on a stage micrometer scale?

Millimeters Signup and view all the answers

During the calibration of an ocular micrometer, what must be aligned with the stage micrometer?

The zero line of the ocular disc scale Signup and view all the answers

What is the primary function of the central canal in the spinal cord?

Acts as a cavity for cerebrospinal fluid Signup and view all the answers

Which layer of the spinal cord is primarily composed of smooth muscle and connective tissue cells?

Tunica Media Signup and view all the answers

What is the composition of the white matter in the spinal cord?

Nerve fibers Signup and view all the answers

Which layer lies beneath the dura mater in the spinal cord?

Pia Mater Signup and view all the answers

Which component is NOT found in the Tunica Externa?

Smooth muscle Signup and view all the answers

How can the gray matter in the spinal cord be described based on its location?

Inner layer surrounding the central canal Signup and view all the answers

What characterizes the ependymal cells in relation to the central canal?

They line the central canal Signup and view all the answers

Which statement accurately describes the structure of the Tunica Intima?

It contains the lining epithelium and elastic tissue. Signup and view all the answers

What is the shape of the nucleus in basophils?

U or J shaped Signup and view all the answers

What percentage of blood leukocytes are lymphocytes?

20-25% Signup and view all the answers

What is true about erythrocytes in mammals compared to other vertebrates?

They are biconcave and anucleated Signup and view all the answers

Which of the following is a type of agranulocyte?

Monocytes Signup and view all the answers

What characteristic distinguishes elastic cartilage from hyaline cartilage?

Numerous fine elastic fibers Signup and view all the answers

What is the function of megakaryocytes in the blood?

Fragment to form platelets Signup and view all the answers

What percentage of blood leukocytes are monocytes?

3-8% Signup and view all the answers

What is a characteristics of cartilage tissue?

It relies on simple diffusion for nourishment Signup and view all the answers

What is the primary function of the cell membrane in an animal cell?

To regulate the flow of substances in and out of the cell Signup and view all the answers

Which type of cell has genetic material that is not membrane bound?

Prokaryotic cell Signup and view all the answers

What shape are smooth muscle cells in the stomach?

Fusiform Signup and view all the answers

What is the function of cytoplasm in an animal cell?

To house organelles and facilitate metabolic processes Signup and view all the answers

What is the significance of staining cells like the human cheek cell?

It enhances visibility under a microscope Signup and view all the answers

Which cell type is characterized by a distinct nucleus and an oval shape, optimizing for oxygen exchange?

Red blood cell Signup and view all the answers

Which component of the animal cell contains genetic material?

Nucleus Signup and view all the answers

Which of the following is true about the structure and function of cells?

Cells differ in size and shape according to their function Signup and view all the answers

What is the shape of an egg cell in a frog’s ovary?

Spherical Signup and view all the answers

What is a characteristic feature of eukaryotic cells?

They have membrane-bound organelles Signup and view all the answers

What is the primary purpose of cell division in living organisms?

For growth and repair Signup and view all the answers

During which phase of the cell cycle does DNA replication occur?

Interphase Signup and view all the answers

What structural form does genetic material take during interphase?

Chromatin Signup and view all the answers

Which phase of mitosis involves the alignment of chromosomes at the equatorial region?

Metaphase Signup and view all the answers

What structures form between centrioles during prophase in mitosis?

Microtubule bodies Signup and view all the answers

Which phase of mitosis sees the disappearance of the nuclear membrane?

Prophase Signup and view all the answers

What occurs during telophase?

Chromosomes uncoil and assume a threadlike appearance Signup and view all the answers

What is a cleavage furrow?

A constriction of the plasma membrane during cytokinesis Signup and view all the answers

In which type of cells can a centrosome typically be observed?

White blood cells Signup and view all the answers

What is the role of the kinetochore during metaphase?

To anchor spindle fibers to chromosomes Signup and view all the answers

Which type of cells are spermatozoa typically classified as?

Threadlike cells Signup and view all the answers

What happens to the mitotic spindles during telophase?

They disappear Signup and view all the answers

What is one of the main functions of white blood cells?

Fighting infections Signup and view all the answers

Study Notes

Compound Microscope and Magnification

Combines eyepiece and objective lens magnifying powers.
Total magnification calculated as Eyepiece (10x) × Objective.
Magnification power is indicated on lens housing.

Stage Micrometer and Ocular Micrometer

Stage micrometer: glass slide with scale, divided into 0.01 mm.
Ocular micrometer is calibrated against the stage micrometer.
Calibration process requires aligning both scales properly on the stage.

Resolving Power

Measures lens quality, affecting image clarity and detail.
High resolving power necessary; poor resolution diminishes usefulness.
Cleanliness of lenses impacts resolution; cleaning before and after use is advised.

Field of View

Refers to the observable area through the lens.
Higher magnification results in a smaller visible area.
Transitioning to higher magnification reveals central parts visible at lower power.

Structure of Frog’s Spinal Cord

Tunica Intima: Internal layer featuring lining epithelium and elastic tissue.
Tunica Media: Intermediate smooth muscle layer with collagen and elastic fibers.
Tunica Externa (Adventitia): External layer with elastic membrane and blood vessels.
Central canal surrounded by columnar ependymal cells viewed at different power levels.
Gray matter (nerve cells, neuroglia) and white matter (nerve fibers) surround the canal.

Blood Composition

Composed of formed elements (cells) and plasma (fluid matrix).
Erythrocytes (red blood cells) lack nuclei in mammals; nucleated in other vertebrates.
Thrombocytes are fragments of megakaryocytes and aid in clotting.

Types of White Blood Cells

Basophils: U or J-shaped nucleus, least numerous (0.5%).
Lymphocytes: Small round cells with an indented nucleus, 20-25% of leukocytes.
Monocytes: Larger with eccentric nuclei, 3-8% of leukocytes.

Supporting Tissue: Cartilage

Elastic Cartilage: Similar to hyaline cartilage, distinguished by numerous elastic fibers.
Chondrocytes are housed in lacunae filled with tissue fluid.
Lacks blood vessels; nourished through diffusion.

Cell Structure and Types

All living organisms consist of cells, forming the basic unit of structure and function.
Prokaryotic Cells: Contain non-membrane-bound genetic material.
Eukaryotic Cells: Genetic material is membrane-bound.
Animal cells typically contain a cell membrane, nucleus, and cytoplasm.

Cell Shape Variations

Fusiform: Spindle-shaped, commonly found in stomach’s muscular layer.
Spherical: Seen in frog’s ovary (egg cells), aids fertilization.
Oval: Observed in frog’s blood smear (red blood cells), maximizes surface area for gas exchange.
Amorphous: Definite shape, found in white blood cells.

Cell Division and Mitosis

Vital for growth, development, and tissue repair.
Process divided into interphase and mitosis.
Interphase: Cell prepares for division; 90% of the cell cycle.
Mitosis: 10% of the cell cycle consisting of stages:
- Prophase: Nuclear membrane disintegrates, chromatin condenses into chromosomes.
- Metaphase: Chromosomes align at the equator, spindle fibers attach.
- Telophase: Cleavage furrow forms, nuclear membrane reappears, leading to daughter cells' formation.

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Description

Explore the fundamentals of compound microscopes, including their magnifying powers and components. This quiz will cover key concepts like the stage micrometer and ocular micrometer calibration, providing essential knowledge for microscopy.