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. Anatomy of the Skin video
Click on title to hyperlink website
This silent film from 1926 takes us through the basic physiology of the human skin, combining anatomical education and basic healthcare advice. We see the epidermis and its replacement, the structure of the underlying dermis, nails, sweat glands and hair follicles.

5. 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

6. The Epidermis
Epidermis

7. 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

8. 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

9. 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

10. High power magnification
Thin skin
S. Corneum
S. Granulosum
S. Spinosum
S. Basale
High power magnification

11. Low power magnification
Thick skin
S. Corneum
S. Lucidum
S. Granulosum
S. Spinosum
S. Basale
Low power magnification

12. Comparing the two together:

13. Pigmented Skin

14. How melanin granules pigment the skin:

15. Melanocyte cytoplams are unstained and appear white
Melanosomes (w/ melanin) are stained dark

16. Pigmented skin
Melanin
granules
Melanocyte

17. Review: ? ? ? ? ? Identify each layer
S. corneum ?
S. Lucidum ?
S. Granulosum ?
S. Spinosum ?
S. Basale
How do you distinguish each layer?

18. Identify as: Thin skin or Thick skin?

19. The Dermis
Dermal papillae
Dermis

20. 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

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

22. Dermal papillae not normally noticeable in thin skin as in thick skin
Review:
Thin skin
Stratified squamous
Thick or thin skin? Tissue type?
Papillary
Areolar CT
Dermal layer? Tissue type?
Reticular
Dense Irregular
Dermal layer? Tissue type?
Dermal papillae not normally noticeable in thin skin as in thick skin

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

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

25. Sudoriferous (sweat) glands
Cross section
Low magnification
High magnification

26. Skin derivatives found in the dermis:
Arrector pili muscle
Sebaceous (oil) gland
Hair Structures

27. Connective tissue root sheath Epithelial root sheath
HAIR STRUCTURES
Hair shaft
Sebaceous gland
Hair root
Connective tissue root sheath
Arrector pili muscle
Epithelial root sheath
(Hair follicle)
Hair Bulb
Hair Papilla

28. Hair Structures Hair Bulb Hair Shaft Hair Root (visible hair)
(embedded)

29. Histology – Hair Structures
Hair Root
Hair Follicle
Hair Bulb
Hair Papilla

30. Histology – Hair Structures
Hair follicle

31. Histology – Arrector pili muscle
(smooth muscle)

32. Histology – Hair Structures
Sebaceous (oil) gland

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

34. Cutaneous Sensory Receptors
Meissner's corpuscle
Free nerve ending
Pacinian corpuscle
Hair follicle receptor
(root hair plexus)

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

36. Meissner’s corpuscles Located in dermal papilla
Histology
Pacinian corpuscles
Located deep in dermis
Meissner’s corpuscles
Located in dermal papilla
External Internal

37. Meissner’s corpuscle - Histology Located in the dermal papilla
Tactile receptors = Discriminative touch

38. Pacinian corpuscle - Histology Located deep in the dermis
Deep pressure
High magnification
Low magnification

39. Review 5 1 6 2 4 3 9 8 7 10

40. Review 9 5 Hair shaft 6 Meissner's corpuscle 7 Free nerve ending 8
Sebaceous (oil) gland 10
Arrector pili muscle 1
Hair root 11
Pacinian corpuscle 2
Hair follicle 3
Hair bulb 4
Hair papilla 5
Eccrine
(sweat) gland 12
Root hair plexus

41. Objective 2 General Sensation
Additional Information

42. Although a part of the nervous system, cutaneous receptors have a direct impact on the integument, and so will be studied in this lab

43. 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

44. 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

45. There are 3 ways to classify cutaneous receptors: Location ………..………….
Stimulus (physiology)
Structure (anatomy)

46. Classifications of Sensory Receptors by Location
Exteroceptors Proprioceptors Interoceptors
Lab 11
BIOL 204
Respond to stimuli arising outside the body:
Touch
Pain
Temperature
Pressure
Detect stretch
Respond to stimuli inside the body (viscera, vessels)

47. Classifications of Sensory Receptors by Stimulus
Nociceptors detect pain
Thermoreceptors detect heat and cold
Mechanoreceptors detect touch and pressure
Photoreceptors detect light
Chemoreceptors detect chemicals and chemical changes
These are the ones you utilized in Lab 12

48. Classifications of Sensory Receptors by Structure
Unencapsulated Encapsulated
Connective tissue
capsule
Free Nerve Ending Encapsulated Nerve Ending

49. Free (Unencapsulated) Nerve Endings
Free nerve ending
in the epidermis
Root hair plexus
Detect hair movement
Mechanoreceptor
Phasic
Detect pain, temperature, tissue movements
Nociceptor (tonic)
Thermoceptor (phasic)
(Mechanoreceptor)

50. Encapsulated Nerve Endings
Examples
Pacinian corpuscle
Meissner’s corpuscle
Detect light pressure, discriminative touch, vibration
Mechanoreceptor
Phasic
Detect deep pressure, stretch, vibration
Mechanoreceptors
Phasic

51. Distribution of cutaneous sensory receptors

52. Functional Mapping of Somatosensory Cortex
The picture represents the sensory information covered by a particular portion of the post-central gyrus.
Consider what impact this may have on the receptive fields of the different areas tested in this experiment.

53. Adaptation: Tonic vs. Phasic
Pain
Stretch
Temperature
Pressure
Sensation diminishes but never ceases
Sensation ceases (becomes unnoticeable)

54. Receptive Fields and Adaptation of Select Receptors
Phasic
Tonic
Phasic
Tonic