Ch 4 Integumentary System PDF

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lab note for integumentary system ...

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Chapter 4 INTEGUMENTARY SYSTEM Introduction The integumentary system is the skin and its accessory structures. The purpose of this lab is to identify the layers of the integument and components of each layer, as well as accessory structures. Objectives: 1. 2. 3.

Identify and describe selected structures of the skin, using slides, models and diagrams. Explain differences between thin skin and thick skin. Apply your knowledge of the skin to a fingerprinting exercise.

Prelab Assignment Prior to the beginning of the laboratory session, review epithelial and connective tissue characteristics and functions. Study in your textbook sections titled “Skin and Subcutaneous Tissue”, “Hair and Nails”, and “Cutaneous Glands”.

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INTEGUMENTARY SYSTEM Exercise 1: Skin Anatomy A. Epidermis List from deep to superficial the five layers of the epidermis found in thick skin. Identify the function or a major distinguishing feature in each layer. Skin Layer Function or Distinguishing Feature Stratum basale Stratum spinousum Spiny; few dendritic cells. Granular keratinocytes. Stratum granulosum Stratum lucidum Smooth. seemingly translucent layer. No nucleus or organelles Dead keratinocytes flaking away. Stratum corneum Label the following diagram of the epidermis:

Stratum corneum Stratum lucidum Stratum granulosum

Living keratinocytes Dendritic cells (Langerhans)

Stratum spinousum

Merkel cells (Tactile) Stratum basale Melanocytes Stem cells

Figure 4.1 Epidermis of Skin

Check Your Understanding Stratum spinousum 1. Which is the thickest layer of the epidermis? ___________________ Stratum lucidum 2. Which layer is found only in thick skin? _______________________

3. Locate the following epidermal cells and describe their function: Cell Function Produces pigment melanin. Melanocyte Langerhans (dendritic) Macrophages that active the immune system. Merkel (tactile) Touch receptors. 2

B. Dermis List from superficial to deep the two layers of the dermis. Identify the function or a major distinguishing feature in each layer. Dermis Skin Layer Function or Distinguishing Feature Papillary layer Areolar LCT, dermal papillae: Gives fingeprint. Reticular layer Dense irregular CT. C. Hair and Hair Follicle Identify if seen on models: Hair shaft: extends beyond skin surface. Three layers (medulla, cortex, cuticle) Hair root: segment deep to epidermis Hair Follicle: tubular sheath surrounds the root. Originates in epidermis and extends deep into dermis. Hair bulb: Matrix: mitotically active basal cells Papilla: blood vessels, nerve and melanocyte Erector pili muscle: erects hair

Figure 4.2 Structure of Hair

D. Skin Glands How do the following glands differ in location and function? Gland Location and Function Produce sweat. Sweat Sebaceous Oil gland, generate and excrete sebum, found all over the body. 3

E. Skin Receptors How do the following receptors differ in function? Receptor Function Free nerve endings Pain, temperature Pressure receptor Pacinian corpuscle Meissner’s corpuscle Touch receptor Using terms from the previous tables, label the following skin diagram:

Hair shaft

Sebaceous gland Epidermal ridges

Dermal papilla Epidermis Tactile corpuscle (Meissner’s) Piloerector muscle Sweat gland

Dermis

Free nerve ending Pacinian corpuscle (Lamellar) Hair follicle Hypodermis

Figure 4.3 Anatomy of the Skin

Check Your Understanding 1. Remember that the skin is an organ and accordingly it comprises two or more tissues. List four types of tissues that you can identify in skin. Dense irregular CT; Areolar CT; Adipose CT; Keratinized squamous _________________________________________________________________________ Stratified keratinized squamous 2. Which type of tissue makes the hair follicle? __________________ Simple cuboidal 3. Which type of tissue are sweat and sebaceous glands? ________________ 4

4. When examining thick skin (palms and soles), which layer is thicker, epidermis or dermis? _______________ 5. When examining thin skin (scalp), which layer is thicker, epidermis or dermis? Hair follicle; Sebaceous gland 6. List two entities that are found in thin skin but are absent in thick skin. _________________ Straum corneum; 7. List two entities that are found in thick skin but are absent in thin skin. _________________ Straum lucidum Exercise 2: Skin Histology Label the different layers of skin and identify the structures: Stratum corneum Epidermis

Stratified squamous keratinized

Dense irregular

Reticular dermis

Figure 4.4 Histology of Skin

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