BIOS 251 Week 5 Integumentary system lab

Student Name

Chamberlain University

BIOS-251 Anatomy & Physiology I

Prof. Name:

Date

OL Lab 5: Integumentary System

Learning Objectives

The objectives of this lab include the following:

Identifying the tissue and cellular features of the skin.
Understanding the structures associated with the skin.
Correlating anatomical features with their respective functions.
Exploring the role of the skin in thermoregulation and wound healing.

Part A: Anatomy of the Skin

I. Microscopic Anatomy of the Skin

The following table summarizes the structures and functions of the microscopic components of the skin.

Structure	Function
Epidermis: Stratum Corneum	Composed of 25–30 layers of flattened, dead keratinocytes; protects deeper layers from injury and microbial invasion.
Stratum Granulosum	Contains 3–5 layers of keratinocytes undergoing apoptosis; keratinocytes produce keratohyalin and lamellar granules.
Stratum Spinosum	Consists of 8–10 layers of keratinocytes with projections of melanocytes and intraepidermal macrophages.
Stratum Basale	Deepest layer; stem cells undergo division to produce new keratinocytes, generating epidermal cells.
Basement Membrane	Separates tissues and provides protection.
Sensory Neuron	Connects to tactile discs and detects touch sensations.
Dermis	Provides tensile strength to resist stretching forces; possesses stretch and recoil ability.
Intraepidermal Macrophages	Arise from red bone marrow; migrate to the epidermis to participate in immune responses, aiding in microbial destruction, although vulnerable to UV damage.
Tactile Epithelium Cell	Associated with sensory nerve endings, forming Merkel discs, which act as slow-adapting touch receptors.
Keratinocyte	Produces keratin, a fibrous protein for skin protection, and lamellar granules, which secrete a water-repellent substance.
Melanocyte	Produces melanin granules that absorb UV radiation to protect skin from damage and contribute to pigmentation.

II. Gross Anatomy of the Skin

The table below outlines the structures of the skin and their respective functions.

Structure	Function
Hair Shaft	Projects above the skin surface.
Blood Vessels	Facilitate blood flow from the heart to the body.
Arrector Pili Muscle	Contracts under emotional stress.
Sebaceous (Oil) Gland	Prevents hair from drying, reduces water loss from the skin, softens skin, and inhibits bacterial growth.
Eccrine Sweat Gland	Regulates body temperature, removes waste, and responds to emotional stress.
Hair Root	Interacts with various structures in the dermis.
Adipose Tissue (Subcutaneous Layer)	Stores fat and contains large blood vessels that nourish the skin.
Lamellated Corpuscle	Adapts quickly to stimuli and senses pressure.
Epidermal Ridges	Strengthens bonds between the epidermis and dermis, enhances grip by increasing friction.
Papillary Region	Contains thin collagen, elastic fibers, dermal papillae, and touch corpuscles.
Reticular Region	Composed of thick collagen, coarse elastic fibers, fibroblasts, and macrophages, providing strength and elasticity to the skin.
Dermis	Vascular region that supports and protects deeper layers of the skin.

Part B: Thermoregulation

Homeostatic Regulatory Mechanism
The three components involved in thermoregulation are:
- A: Sweat glands.
- B: Hypothalamus.
- C: Blood vessels.
Physiological Events in Thermoregulation
When internal temperature changes, central nervous system (CNS) sensors send messages to the hypothalamus. The hypothalamus then activates mechanisms to restore balance. If cooling is needed:
- Sweating: Sweat evaporates from the skin, dissipating heat and lowering internal temperature.
Conditions Related to Temperature Dysregulation
- Increased temperature: Hyperthermia.
- Decreased temperature: Hypothermia.

Part C: Skin Wound Healing

1. Epidermal vs. Dermal Wound Healing

Epidermal Wound Healing	Dermal Wound Healing
Involves only the epidermis; minimal risk of infection.	Involves deeper layers; higher infection risk.
Keratinocytes re-epithelialize the wound site.	Scar tissue forms, lacking the original tissue’s functionality.
Heals quickly with few complications.	Healing prioritizes life preservation over tissue functionality.

2. Initial Step in Wound Healing and Its Significance

Homeostasis Phase: Blood vessels constrict, and platelets aggregate to form clots, sealing the wound. This prevents further blood loss and lays the foundation for granulation tissue formation.
Significance: Ensures minimal blood loss and creates a scaffold for new tissue development.

3. Role of Inflammation in Healing

Inflammation prevents infection and supports healing by recruiting white blood cells, growth factors, and nutrients to the site.

4. Fibrosis in Deep Wound Healing

Excessive fibroblast activity and collagen deposition result in scar tissue, leading to wound contraction or fibrosis.

Part D: Case Studies

Case Study 1: Burns

Partial Thickness Burns:
- Second-degree burns that involve the epidermis and varying layers of the dermis.
- Superficial burns affect the papillary layer, while deep burns reach the reticular layer.
Loss of Sensation:
Deep burns damage nerves in the reticular layer, causing reduced or no sensation.
Burn Percentage Using Rule of Nines:
- Anterior legs: 18% per leg.
- Total: 36%.

Case Study 2: Hypothermia

Definition: A condition resulting from prolonged exposure to cold, leading to a dangerous drop in body temperature.
Temperature Detection: Thermoreceptors in the skin.
Control Center: Hypothalamus.
Blood Vessel Response: Vasoconstriction reduces blood flow to conserve heat.
Hair Response: Erect hairs trap warm air to minimize heat loss.
Feedback Mechanism: Negative feedback involving shivering generates heat to restore normal body temperature.

References

Tortora, G. J., & Derrickson, B. (2020). Principles of Anatomy and Physiology (15th ed.). Wiley.