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Week 13 The Integumentary System.

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Presentation on theme: "Week 13 The Integumentary System."— Presentation transcript:

1 Week 13 The Integumentary System

2 The integumentary system consists of:
The Skin Its Derivatives Hair Nails Glands

3 Objective 1 Structures of the Integument

4 Skin Layers The two primary skin layers are: Plus:
Epidermis: superficial layer made of keratinized stratified squamous epithelium (subdivided into 4-5 layers) Dermis: consists of areolar tissue and dense irregular connective tissue (subdivided into 2 layers) Plus: Hypodermis: attaches skin to underlying structures; made of areolar tissue and variable amounts of adipose

5 The superficial layer of the Integument
The Epidermis is: The superficial layer of the Integument Composed of keratinized stratified squamous epithelium Majority of cells are called keratinocytes Avascular

6 The epidermis has either 4 or 5 cell layers
Thin skin has 4 layers; the stratum lucidum is absent Thick skin of the palms and soles of the feet has 5 layers

7 Layers of the Epidermis:
Mnemonic? Come Let’s Get Some Beer… Layers of the Epidermis: Layer Structure Stratum corneum rows of flat dead keratinocytes Stratum lucidum 2-3 rows of dead keratinocytes, found only in thick skin Stratum granulosum 3-5 rows of flat keratinocytes Stratum spinosum 8-10 rows of flat keratinocytes, Stratum basale single layer of keratinocytes; some melanocytes, and Merkel cells Number of rows are less in thin skin and more in thick skin

8 Thin vs. Thick Skin

9 Identify as: Thin skin or Thick skin?

10 The Dermis Dermal papillae Dermis

11 Composed of connective tissue
epidermis The Dermis is: Deep to the epidermis Composed of connective tissue Consists of a superficial papillary layer and a deep reticular layer Contains sensory receptors, nerve fibers, glands, and hair follicles Papillary layer dermis Reticular layer

12 Layers of the Dermis Papillary Layer Areolar C.T. Reticular Layer
Collagen fibers Elastic Reticular fibers Reticular Layer Dense Irregular C.T. Collagen fibers

13 Skin Derivatives Hair shaft Pore Sebaceous (oil) gland
Arrector pili muscle Hair root Hair follicle Hair bulb Hair papilla Eccrine (sweat) gland

14 Skin derivatives found in the dermis:
Sudoriferous (sweat) glands: Eccrine Apocrine

15 Sudoriferous (sweat) glands
Cross section Low magnification High magnification

16 Skin derivatives found in the dermis:
Hair Shaft Arrector pili muscle Sebaceous (oil) gland Hair Root Hair Follicle Hair Bulb Hair Papilla

17 Hair Structures Hair Bulb Hair Shaft Hair Root (visible hair)

18 Histology – Hair Structures
Hair Root Hair Follicle Hair Bulb Hair Papilla

19 Histology – Arrector pili muscle
(smooth muscle)

20 Histology – Hair Structures
Hair follicle

21 Histology – Hair Structures
Sebaceous (oil) gland

22 Histology – Hair Structures
Sebaceous (oil) gland Hair shaft Hair follicle Hair root Arrector pili Hair Root Hair Follicle Sebaceous (oil) gland

23 Cutaneous Sensory Receptors
Identify these from models Meissner's corpuscle Free nerve ending Pacinian corpuscle Hair follicle receptor (root hair plexus)

24 The cutaneous sensory receptors are nerve endings that receive stimuli from the external environment through the skin (Exteroceptors) Spinal cord

25 Cutaneous Sensory Receptors

26 Meissner’s corpuscles Located in dermal papilla
Histology Pacinian corpuscles Located deep in dermis Meissner’s corpuscles Located in dermal papilla External Internal See skin models for 3-D structure and structural clarity

27 Note: Although a part of the nervous system, cutaneous receptors can have a direct impact on the integument

28 Consequences of Sensation Loss Diabetic neuropathy
Nerve damage due to decreased blood flow Ulcers and infections - skin damage undetected Charcot's Joint (neuropathic arthropathy) Loss of motor function

29 Consequences of Sensation Loss Leprosy (Hansen’s disease)
Lesions and infections from inability to detect tissue and bone injury resulting from nerve damage caused by the bacterium Mycobacterium leprae Appendage loss due to infection Blindness and nasal collapse also result from nerve damage

30 Objective 2 General Sensation

31 Distribution and Discrimination
Experiment A – 2-Point Discrimination Determine touch receptor density Experiment B – Mapping Temperature and Touch Receptors Compare density of cold, heat and touch receptors Experiment C – Tactile Localization Localizing the stimulus (receptive field) ? cm

32 Adaptation Experiment D – Sensory Adaptation
Timing pressure sensation adaptation Experiment E – Temperature Receptor Adaptation Compare sensation of hand immersed in hot water with sensation of hand already immersed (adapted)

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