Human Histology and Biopsies

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Questions and Answers

Which of the following statements best characterizes the field of human histology?

The study of genetic mutations that cause tissue related diseases.

The study of large-scale anatomical structures in humans using a microscope.

The examination of microscopic structures of biological materials derived from humans and their functional relationships. (correct)

The analysis of chemical reactions in human cells involving tissues.

What is the primary goal of histopathology?

To identify the genetic makeup of tissue cells.

To study the large-scale anatomy of organs.

To prepare small tissue samples for examination under a microscope. (correct)

To perform surgical procedures for tissue removal.

When might fresh tissue samples be examined?

When tissues are preserved in a lab for later study.

When evaluations of tissue state are required immediately after removal. (correct)

When a specific tissue sample is needed, days after surgery is completed

When a research protocol requires specific preparation.

What is the primary advantage of a punch biopsy in the the evaluation of a skin lesion?

It provides a full-thickness sample of the skin, crucial for diagnosis. (D) Signup and view all the answers

Which of the following are commonly removed with a shave biopsy?

Warts, lesions, and some skin cancers. (D) Signup and view all the answers

What is the purpose of the clearing process in tissue preparation?

To make the tissue translucent for better embedding (D) Signup and view all the answers

Which reagent is considered the best for dealcoholization in tissue preparation?

Ethanol (B) Signup and view all the answers

Which of the following is NOT a common clearing agent used in the tissue preparation process?

Hematoxylin (B) Signup and view all the answers

What is the main purpose of using preserved tissues in histopathology?

To study tissues in more detail through sections and smears (D) Signup and view all the answers

Which of the following best describes an incisional biopsy?

It obtains only a small sample of tissue (B) Signup and view all the answers

What is the main objective of the staining process in histology?

To enhance visibility of tissue architecture (A) Signup and view all the answers

Which classification studies tissues based on the chemical reaction of the stain?

Histochemical (D) Signup and view all the answers

Which procedure uses a big needle to separate tissue?

Teasing (D) Signup and view all the answers

What is a common application of crushing in a biopsy?

Diagnosis of leukemia and lymphoma (A) Signup and view all the answers

What is one of the key differences between excisional and incisional biopsies?

The amount of sample obtained differs (C) Signup and view all the answers

What is the primary purpose of fixation in tissue processing?

To ensure minimum loss or distortion during treatment (D) Signup and view all the answers

Which of the following statements about fine needle biopsy is true?

It is less invasive than core needle biopsy. (C) Signup and view all the answers

What is one of the secondary goals of fixation during tissue processing?

To harden and protect the tissue from damage (A) Signup and view all the answers

In the context of biopsy procedures, what characterizes an endoscopic biopsy?

It uses a flexible tube with light and camera for visualization. (C) Signup and view all the answers

Which of the following describes a core needle biopsy accurately?

It collects a core sample of tissue and is more invasive. (D) Signup and view all the answers

What is the recommended amount of 10% neutral buffered formalin for preservation relative to the tissue sample?

20x the size of the sample (C) Signup and view all the answers

Which biopsy technique involves the use of a flexible tube with a camera?

Endoscopic biopsy (A) Signup and view all the answers

What is the primary function of paraffin wax in tissue processing?

To provide a hard consistency for cutting sections (C) Signup and view all the answers

What distinguishes a fine needle biopsy from other types of biopsy procedures?

It utilizes aspiration to collect cell samples. (B) Signup and view all the answers

What temperature is typically set for the paraffin oven during the embedding process?

2-5 degrees C above the melting point (B) Signup and view all the answers

Which type of staining is associated with materials that have a net negative charge?

Hematoxylin staining (D) Signup and view all the answers

What is the purpose of the clearing agent in the tissue embedding process?

To replace the dehydrating agents in the tissue (D) Signup and view all the answers

Which embedding medium is particularly suitable for hard and dense tissues such as teeth and bones?

Collodion/Celloidin (D) Signup and view all the answers

What is the common consequence of improper dehydration before embedding?

Incomplete infiltration of wax (A) Signup and view all the answers

What is a characteristic of temporary mountants used in microscopy?

They often dissolve in solvents (C) Signup and view all the answers

Which of the following is true about acidophilic substances in tissue staining?

They react with eosin and basic dyes (C), They are positively charged materials (D) Signup and view all the answers

What is the primary purpose of endoscopic biopsies?

To identify abnormalities in organisms and guide treatment decisions (A) Signup and view all the answers

Which of the following statements about a punch biopsy is correct?

It involves a circular cutting tool to extract a cylindrical piece of skin. (A) Signup and view all the answers

What is the purpose of dehydration in tissue processing?

To remove intracellular and extracellular water prior to wax impregnation. (A) Signup and view all the answers

What is the suggested volume of decalcification solution relative to the sample size?

20 times the amount of the sample (A) Signup and view all the answers

Which of the following steps is crucial when preparing alcohol solutions for dehydration?

Following an ascending order from 70% to 100%. (C) Signup and view all the answers

Why is it important to consider the size of samples when using a microtome machine?

Size affects the fragility of the ribbons produced. (A) Signup and view all the answers

What is the significance of the temperature in the filtration box for tissue samples?

The temperature should be black but not specified. (C) Signup and view all the answers

Which of these fixative solutions is commonly used for tissue preservation?

Aldehydes (formalin) (C) Signup and view all the answers

Study Notes

Human Histology

Defined as the microscopic study of human biological structures and their functional relationships.
Involves intertwining with biology, biochemistry, physiology, and pathology.

Histopathology

Deals with sample tissue preparation for microscopic examination.
Techniques involve using scalpels, needles, and flexible cannulae.
Samples can be examined as fresh tissues, or preserved tissues.

Common Types of Biopsies

Surgical Biopsy:
- Excisional: Removing the entire tissue mass.
- Incisional: Removing a portion of the tissue.
- Key difference: Amount of tissue obtained.
Needle Biopsy:
- Fine needle: Collects cellular samples, less invasive.
- Core needle: Extracts tissue cores, thicker instruments.
- Guided by ultrasound or MRI.
Endoscopic Biopsy:
- Uses an endoscope to visualize and collect tissue samples from internal organs.
- Used for diagnosing various conditions (cancers, infections).
- Less invasive than surgical biopsies.
Punch Biopsy:
- Removes a small, cylindrical piece of skin.
- Includes all skin layers (epidermis, dermis).
- Used to diagnose skin conditions (cancers, lesions).
Shave Biopsy:
- Removes superficial skin layers using a blade or scalpel.
- Diagnoses skin lesions (warts, skin cancers).
Bone Marrow Biopsy:
- Uses a large needle for extracting bone marrow samples.
- Diagnoses conditions like leukemia and lymphoma.

Preserved Tissues

Examination of tissue sections and smears, permanently preserved, stained, & mounted on slides.
A more effective approach to studying tissues for diagnosis

Steps in Processing Preserved Tissues(FDD-CIET-SSML)

Fixation (F):
- Preservation of tissue components to withstand further processing.
- Crucial step for preserving morphology and chemical integrity.
- Typically uses 10% neutral buffered formalin.
Decalcification (D): Removing calcium from samples containing it. (Optional)
Dehydration (D): Removing water from the tissue.
Clearing: Replacing dehydration agents with a translucent agent.
Impregnation: Filling tissue spaces with a solidifying medium to allow cutting.
Embedding: Placing impregnated tissue in a solidified mold.
Trimming(T): optional step for refining the mold
Sectioning (S): Slicing the embedded tissue into thin sections using a microtome.
Staining (S): Dyeing the sections to highlight specific structures and provide better visualization for analysis.
Mounting (M): Mounting stained sections onto slides using a mounting medium and coverslip

Additional Staining Information

Hematoxylin and Eosin (H&E): Common staining technique for highlighting cellular details.
Cell components with a negative charge (DNA, RNA) stain basophilic with hematoxylin, while positive components stain acidophilic with eosin.

Clearing Techniques

Common clearing agents include xylene/xylol, alcohol, toluene, Benzene, chloroform, and cedarwood oil.
Ethanol is frequently used in clearing, and methanol is not recommended due to toxicity.

Tissue Impregnation

Techniques involve paraffin wax, collodion, or gelatin impregnation, based on specimen needs.

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Description

Explore the intricacies of human histology, including the microscopic study of biological structures and their functional relationships. Delve into the various types of biopsies, including surgical and needle procedures, and learn about the methods used for tissue examination.