Questions and Answers
What are human blood cells primarily composed of?
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?
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What describes the structure of human hair?
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What is a notable feature of cat hair?
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What are the parts of sperm?
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What is the structure of hair?
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The ______ is the outside layer of hair with scale patterns.
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What is the composition of the cortex in hair?
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What is the medulla in hair?
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What does PMI stand for?
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What is limnology?
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What are diatoms?
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What are the two shapes of diatoms?
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What do chromatophores do?
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How do diatoms travel during drowning?
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Drowning in freshwater leads to water being drawn from blood to lungs.
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What are the downsides of using diatoms in forensic investigations?
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At least ______ diatoms have to be in the body to consider drowning.
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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.