Human and Mammalian Biological Structures

Questions and Answers

What are human blood cells primarily composed of?

Erythrocytes (correct)

Leukocytes

Thrombocytes

All of the above

What is the function of human columnar epithelium?

Lines most organs in the digestive and respiratory tract, contributing to greater surface area.

What are the layers of mammalian skin?

Epidermal, dermal, hypodermal (or subcutaneous).

What is a characteristic appearance of human cheek cells?

Flat appearance. Signup and view all the answers

What describes the structure of human hair?

Smooth, solid rods with a small and undefined medulla. Signup and view all the answers

What is a notable feature of cat hair?

Medulla has a ladder structure. Signup and view all the answers

What are the parts of sperm?

Head, midpiece, and tail. Signup and view all the answers

What is the structure of hair?

Shaft, root, and hair bulb. Signup and view all the answers

The ______ is the outside layer of hair with scale patterns.

cuticle Signup and view all the answers

What is the composition of the cortex in hair?

Compact, elongated cells containing pigment (melanin). Signup and view all the answers

What is the medulla in hair?

Composed largely of air spaces. Signup and view all the answers

What does PMI stand for?

Post Mortem Interval. Signup and view all the answers

What is limnology?

The study of freshwater ecology. Signup and view all the answers

What are diatoms?

Eukaryotic algae with a unicellular structure and silica shell. Signup and view all the answers

What are the two shapes of diatoms?

Centrales Signup and view all the answers

What do chromatophores do?

Help synthesize their own food. Signup and view all the answers

How do diatoms travel during drowning?

They enter a person's lungs and are carried throughout the body. Signup and view all the answers

Drowning in freshwater leads to water being drawn from blood to lungs.

False Signup and view all the answers

What are the downsides of using diatoms in forensic investigations?

Contamination from other sources and inactive circulatory system. Signup and view all the answers

At least ______ diatoms have to be in the body to consider drowning.

20/10g of lung tissue. Signup and view all the answers

Study Notes

Human Blood Cells

Erythrocytes are denucleated red blood cells.
White blood cells are larger and contain purple nuclei.

Human Columnar Epithelium

Comprises the lining of most organs in the digestive and respiratory tracts.
Structure increases surface area for absorption and secretion.

Mammalian Skin Section

Divided into three layers: epidermis (top), dermis (middle), and hypodermis/subcutaneous (deepest).
Hair follicles function as sensory receptors.

Human Cheek Cells

Characterized by a flat appearance.
Commonly found in the epidermis and often collected at crime scenes.

Human Hair

Composed of smooth, solid rods.
Medulla appears small and undefined.

Cat Hair

The medulla exhibits a distinctive "ladder" structure.

Sperm Structure

Consists of three parts: head, midpiece, and tail.
The head contains haploid genetic material.

Structure of Hair

Shaft located above the head, while the root is beneath it.
Hair bulb is positioned at the bottom.

Cuticle of Hair

The outer layer features distinct scale patterns.
Types include:
- Coronal: encircles completely, common in rodents.
- Spinous: long, thin triangular shapes, typical in cats.
- Imbricate: short, flat, wide scales, found in humans and some others.

Cortex of Hair

Composed of compact, elongated cells containing melanin, providing hair color.
Represents the largest portion of the hair shaft.
Air pockets within the cortex can be used to test hair.

Medulla of Hair

Made up mainly of air spaces.
Can be categorized as continuous, intermittent, or fragmented based on the structure.

PMI (Post-Mortem Interval)

Refers to the duration since a person has died.

Limnology

The scientific study focusing on freshwater ecology.

Diatoms

Unicellular, eukaryotic algae characterized by a silica shell.

Diatom Shapes

Pennates: bilaterally symmetrical and float in water.
Centrales: radially symmetrical and primarily sessile, can move with flagella.

Chromatophore Function

Structures that enable organisms to synthesize their own food.

Diatom Travel Mechanism

Diatoms enter the lungs during drowning and travel through the body via the circulatory system.

Drowning in Fresh vs. Saltwater

In freshwater, water rapidly flows from the lungs to the bloodstream.
In saltwater, the process is reversed, pulling water from the bloodstream to the lungs, resulting in a longer death process.

Downsides of Using Diatoms

Potential contamination from other sources.
Ineffective if the circulatory system is not active to absorb diatoms.

Quantification for Drowning Evidence

A minimum of 20 diatoms per 10 grams of lung tissue is required to consider drowning as the cause of death.

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Description

Explore the fascinating world of human and mammalian biological structures. This quiz covers various topics including blood cells, epithelial tissues, skin layers, and hair composition. Test your knowledge on the unique characteristics and functions of these essential components.