Histology Basics and Microscopy Techniques

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Questions and Answers

What is the primary role of the cell membrane?

Store genetic information for the cell.

Generate energy for cellular functions.

Regulate the passage of materials into or out of the cell. (correct)

Provide structural support to the cell wall.

What structural feature describes the kidney of the cell membrane as viewed with an electron microscope?

Tessellated pattern.

A single dark line.

Bulbous formations.

Trilaminar with two dark lines and one light line. (correct)

Which component of the cell membrane contributes to its stability and rigidity?

Glycocalyx.

Phospholipids.

Cholesterol. (correct)

Integral proteins.

Which type of protein is embedded within the lipid bilayer and functions as a channel for water-soluble substances?

Trans-membranous protein. Signup and view all the answers

What describes the function of the cell coat, also known as the glycocalyx?

Facilitates cell to cell recognition and adhesion. Signup and view all the answers

What type of transport involves the engulfing of solid particles by the cell membrane?

Phagocytosis. Signup and view all the answers

Which staining method is specifically associated with visualizing the carbohydrate components of the cell membrane?

PAS. Signup and view all the answers

What is the primary composition of the lipid bilayer in the cell membrane?

Phospholipids and cholesterol. Signup and view all the answers

What is the primary focus of histology?

The microscopic structure of cells and tissues. Signup and view all the answers

Which structure is considered a membranous organelle?

Mitochondria Signup and view all the answers

What color does Hematoxylin stain appear under a microscope?

Blue Signup and view all the answers

Which of the following microscopy techniques allows the highest level of magnification?

Transmission EM Signup and view all the answers

How does the structure of a lysosome correlate with its function?

Its membrane-bound nature protects cellular contents from degradation. Signup and view all the answers

Which of the following stains are specifically used to identify carbohydrates in histological sections?

Periodic Acid-Schiff (PAS) Signup and view all the answers

What is one of the components of the cytoplasm?

Mitochondria Signup and view all the answers

Which of the following organelles is classified as non-membranous?

Cytoskeleton Signup and view all the answers

Study Notes

Histology

The study of the normal microscopic structure of cells (cytology) and tissues in relation to their functions.
Hierarchy: Cells → Tissues → Organs → Organisms

Staining

Differentiation of various structures by taking different colors.
Types:
- Acidic:
  - Eosin (E): Pink
  - Hematoxylin & Eosin (H&E): Purple
- Basic:
  - Hematoxylin (H): Blue

Special Stains

Carbohydrates:
- Periodic Acid Schiff (PAS): Magenta
Lipids:
- Frozen sections are used.
- Sudan III: Orange
- Sudan Black: Black
- Osmic acid: Black

The Microscope

Magnifies images to reveal details of the object.
Types:
- Light microscope: 40, 100, 400, 1000 times magnification
- Electron microscope: Up to 50,000 times magnification.
  - Transmission EM
  - Scanning EM

Structure of the Cell

Cell membrane: Surrounds the cell and regulates material passage.
Cytoplasm: Contains:
- Cytosol (cytoplasmic matrix)
- Cell organelles
- Cell inclusions
Nucleus

Cell Organelles

Living components in the cytoplasm
Types:
- Membranous:
  - Cell membrane
  - Mitochondria
  - Endoplasmic reticulum (smooth and rough)
  - Golgi apparatus
  - Lysosomes
- Non-membranous:
  - Ribosomes
  - Cytoskeleton
    - Microtubules (as centriole, cilia)
    - Filaments (Thin, intermediate, & thick)

The Cell Membrane

The outer limiting membrane that surrounds the cell.
Light microscope (LM): Too thin to be seen, but its carbohydrate contents can be stained by PAS.
Electron microscope (EM): Trilaminar structure: two dark (electron-dense) lines separated by a light one (electron-lucent).
- Called unit membranes

Chemical Structure

Lipid:
- Phospholipid
- Cholesterol
Protein:
- Integral (intrinsic protein)
- Peripheral (extrinsic protein)
Carbohydrate:
- Cell coat (Glycocalyx)

Lipid Structure

Phospholipid double layers:
- Hydrophilic polar head (outwards)
- Hydrophobic non-polar tail (center)
Cholesterol: Located on the cytoplasmic side of the lipid bilayer, giving stability and rigidity to the membrane. It forms channels for lipid-soluble substances.

Integral Protein

Located within the lipid bilayer and not easily extracted.
Small particles: Partially embedded in the lipid bilayer.
Trans-membranous protein: Large in size, completely embedded in the lipid bilayer and crosses it. It acts as channels for water-soluble substances.

Peripheral Protein

Located on the periphery and loosely attached to the outer surface of the cell membrane.
Easily extracted.

Carbohydrate Component

Consists of glycolipids and glycoproteins.
Projects from the external surface of the membrane, forming the:
- Cell coat or Glycocalyx:
  - PAS positive
  - EM: Fuzzy appearance
  - Thick in the intestine

Functions of the Cell Membrane

Maintains the internal composition of the cell.
Cell coat (glycocalyx) functions:
- Attachment to other cells:
- Receptors:
- Cell-to-cell recognition:
- Immunity:

Bulk Transport

Exocytosis:
Endocytosis:
- Phagocytosis:
- Pinocytosis:

MCQ

The cell coat is:
- Well developed and thick in the intestine.
How the cell membrane appears by EM:
- Trilaminar.
Which substance of the following is responsible for decreasing lipid bilayer movement?
- Cholesterol molecule.
Which of the following stains is responsible for staining of the cell membrane?
- PAS.

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Description

This quiz covers the fundamentals of histology, focusing on the microscopic structure of cells and tissues. It includes information about different staining techniques, types of microscopes, and the functions of various cellular components. Test your knowledge and understanding of these essential concepts in histology.