1. Week 13
The
Integumentary
System

2. The integumentary system consists of the skin and its derivatives: hair, nails, and glands

3. Objective 1: Structures of the Integument
The two primary skin layers are:
Epidermis: superficial layer made of keratinized stratified squamous epithelium
Dermis: consists of areolar tissue and dense irregular connective tissue
Hypodermis: attaches skin to underlying structures; made of areolar tissue and variable amounts of adipose

4. 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

5. 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

6. 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

7. Hair follicles and sebaceous glands are epithelial derivatives that live in the dermis

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

9. 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

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

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

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

13. Sudoriferous (sweat) glands are also found in the dermis

14. Other important structures found in the dermis are cutaneous sensory receptors

15. Sensory receptors can be “encapsulated” or “unencapsulated” nerve endings
Connective tissue
capsule
Free Nerve Ending Encapsulated Nerve Ending

16. Free nerve endings mediate the following sensations:
Nociceptors detect pain
Thermoreceptors detect heat and cold
Proprioceptors detect stretch
Root hair plexus detect hair movement
Root hair plexus
Free nerve ending
in the epidermis

17. Encapsulated Receptors
Pacinian corpuscles mediate
deep pressure
Meissner’s corpuscles mediate
light touch

18. Objective 2: Plotting Eccrine Sweat Gland Distribution
Follow the instructions on page 61 of the lab manual
Do Not perform this test if you are allergic to iodine
The purpose of this experiment is to compare the density of eccrine sweat glands on the forehead, anterior antebrachium, palmar surface of the hand, and the crural region
Class data will be gathered

19. Objective 3: General Sensation
Perform each experiment in pairs, one member is the subject the other is the recorder. Then switch roles and perform the experiments again.
Some data will be collected from everybody and class data used in your report.
You are required to write a lab report for these series of experiments. Follow the format in your lab manual, and the instructions given by your lab instructor.
The lab report is due the week after the lab practical