Exercise 13 - The Integumentary System PDF

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Lab packet exercise 13...

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EXERCISE 13: The Integumentary System Reference: Chapter 6 OBJECTIVES:    

To describe the structure and function of the integumentary system To identify various features of the integumentary system and describe their structure To name and identify the layers of the epidermis and describe their characteristics To compare and contrast the epidermis and dermis structurally and functionally

A. Functions of the Skin Identify and describe the six functions of the skin. 1. resistance to trauma & infection 2. barrier functions: UV, water, chemicals 3. Vitamin D synthesis 4. sensation 5. thermoregulation 6. nonverbal communication

B. The Epidermis Skin models and slides: Observe the following structures / components of the epidermis. Describe their structure and function. Complete the table, filling in the epidermal and dermal layers starting with the deepest layer. Be able to identify the various layers using microscopy. Epidermis = keratinized stratified squamous epithelium 5 layers, usually 4, basement membrane stem cells

Undifferenticated cells, eventually give rise to keratinocytes

keratinocytes

Found in epidermis, Synthesizes keratin, formation of vitamin D

melanocytes

Found in deepest layer, synthesizes melanin, give skin colour pigment

free nerve endings Deepest layer, mechanoreceptors, light touch

dendritic cells

Immune cell, surveillance cells

LayersEpidermal

Tactile cells (merkel cells)

Stratum corneuum

Layer of dead keratinocytes, connected through desnosomes, skin peeling. Replaced every 4 layers

Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale

Missing in thin skin, found in palms/soles, dead cells, extra protection against water Thin layer (3-5 cell layers) biggest producer of keratin Interspersed with dendritic cells but mainly made up of keratinocytes, produce keratin & water proofing glycolipid All stem cells are found. All keratinocytes found in layers above are produced from stem cells found in this layer (mitosis) existing cells pushed up. Has tactile melanocytes

C. The Dermis Skin models and slides: Observe the following structures / components of the dermis. Describe their structure and function. Complete the table, filling in the epidermal and dermal layers starting with the deepest layer. Be able to identify the various layers using microscopy. Label these features on the model. dermal papillae

Ridges that rise up on the wave. increase SA & aids in adhesion

epidermal ridges

Ridges that slope downward on the wave, increase SA & aids in adhesion More superficial, made up of areolar connective tissue. Big role in diffusion of nutrients Deeper part, made up of dense irregular connective tissue. Resisting stretching motions

papillary layer reticular layer tactile corpuscle

Found in superficial layer. Light touch

lamellar (Pacinian) corpuscle

Deeper part. Sense pressure & vibration

Hypodermis     

Subcutaneous tissue More adipose & areolar tissue Vascular Adipose deposition Where adipose is deposited (when you gain weight)

3. Glands. Observe microscope slides of skin cross-sections that include eccrine and sebaceous glands. Sketch your observations. Label the first three on the integumentary figure above. Describe the function of the following exocrine glands. eccrine / merocrine apocrine sebaceous ceruminous mammary

True sweat glands, function through merocrine secretion, simple coiled tubular glands, exocytosis Function through merocrine & exocytosis. Found in certain locations (inguinal, axillary, areolar), active at puberty, scent Function through holocrine secretion, produces oil (sebum) = lubrication. Found next to hair follicles Found in dermis. Modified apocrine sweat glands found in ear canal & makes ear wax Found in dermis. Found in breast tissue, produces breast milk...