The skin & integumentary system is based on the CTEVT syllabus for diploma in health sciences, Anatomy, and physiology,

1. Topics to Study

2. The integument as an
organ, and is an alternative
name for skin.
The integumentary system
includes the skin and the skin
derivatives hair, nails, and
glands.
The Skin & integument as an organ:

3. The Skin & Integument
Is the largest system of the body
 15-20% of body weight, (4kg )
 1.5 to 2m2
in area, 0.3 to 3mm thickness
 The integument is made up of two parts:
1. Cutaneous membrane
a. Epidermis– Superficial epithelium
b. Dermis – underlying Cutaneous tissue with blood supply
2. Accessory structures
a. Hair
b. Nails
c. Exocrine Glands

4. Types of Membrane
-Thin layers of epithelial tissue
-Bound to an underlying layer of connective tissue.
-Membranes cover, protect, or separate other structures or tissues in the
body.
There are four types of Membrane:
1. Cutaneous membranes:
-a layer of stratified squamous epithelium (epidermis) firmly attached to
a thick layer of dense connective tissue (dermis).
-exposed to air and is dry.

5. 2.Serous membranes:
-consist of simple squamous epithelium (a mesothelium) supported by
a layer of connective tissue (areolar).
These moist membranes line the closed, internal divisions of the
ventral body cavity.
The three types of serous membranes are: P3
--The pleura, lining the pleural cavities and covering the lungs;
--The peritoneum, lining the peritoneal cavity and covering the
abdominal organs; and
--The pericardium, lining the pericardial cavity and covering the heart.

6. 3. Mucus membranes:
-consist of epithelial tissue (usually stratified squamous or simple
columnar epithelia) on a layer of loose connective tissue called the
lamina propria (from the Latin, meaning “one’s own layer”).
-The mucosae line the body cavities that open to the exterior, such as
the digestive, respiratory, reproductive, and urinary tracts.
-Are kept moist by bodily secretions.

7. 4. Synovial Membrane:
--are composed of connective tissue.
--They surround the cavity of joints, filling
the space with the synovial fluid that they make.
--The synovial fluid lubricates the ends of the bones
allowing them to move freely.

8. Protection
 First line of defense against
 Bacteria
 Viruses
 Protects underlying structures from
 Ultraviolet (UV) radiation
 Dehydration
Vitamin D production
 Needed for calcium absorption
Sensation
 Sensory receptors

9.  Body temperature regulation
If too hot
 Dermal blood vessels dilate
 Vessels carry more blood to surface so heat can escape
If too cold
 Dermal blood vessels constrict
 Prevents heat from escaping
 Excretion
Small amounts of waste products are lost through
perspiration

10.  Understanding how the skin can function in these many
ways starts with understanding the structure of the 3
layers of skin
The Epidermis
Epithelial tissue
Dermis
Dense connective tissue proper – irregular
Hypodermis
Subcutaneous tissue- loose connective tissue proper
and adipose tissue

11. Epidermis
Dermis
Hypodermis
or
subcutaneous layer

12. Thin Skin
Covers most of the body
Has four layers of keratinocytes
Thick Skin
Covers the palms of the hands and soles of the feet
Has five layers of keratinocytes

13. The Epidermis
Is a vascular stratified squamous epithelium
Nutrients and oxygen diffuse from capillaries in the dermis
Cells of the Epidermis
Keratinocytes
Contain large amounts of keratin about 90%
Strengthens the skins and prevents from excessive water
loss.

14. Melanocytes:
-synthesizes melanin, which barrier against UV radiation.
Langerhans’ cells:
-class of macrophages, role in immunity acting as antigen cells,
produced in bone marrow.
Merkel cells:
-acts as a touch receptor.

15. Thick skin LM  210
Surface
Stratum
corneum
Stratum
lucidum
Stratum
granulosum
Stratum
spinosum
Stratum basale
Basement
membrane
Dermis
Papillary layer of dermis
E
P
I
D
E
R
M
I
S

16. Stratum Basale
Is attached to basement membrane by
hemidesmosomes
Forms a strong bond between epidermis and dermis
Forms epidermal ridges (e.g., fingerprints)
Dermal papillae (tiny mounds)
Increase the area of basement membrane
Strengthen attachment between epidermis and dermis
Has many basal cells or germinative cells

17. Stratum Spinosum — the ―spiny layer‖
Produced by division of stratum basale
Eight to ten layers of keratinocytes bound by
desmosomes
Cells shrink until cytoskeletons stick out (spiny)
Continue to divide, increasing thickness of epithelium
Contain dendritic (Langerhans) cells, active in
immune response

18. Stratum Granulosum — the ―
grainy layer
‖
Stops dividing, starts producing
Keratin
A tough, fibrous protein
Makes up hair and nails
Keratohyalin
Dense granules
Cross-link keratin fibers

19. Stratum Lucidum — the ―clear layer‖
Found only in thick skin
Covers stratum granulosum
Stratum Corneum — the ―horn layer
‖
Exposed surface of skin
15 to 30 layers of keratinized cells
Water resistant
Shed and replaced every 2 weeks

20. The Dermis
 Located between epidermis
and subcutaneous layer
 Anchors epidermal accessory
structures (hair
follicles, sweat glands)
 Two components
1. Outer papillary layer
2. Deep reticular layer Dermis

21.  The Papillary Layer
Consists of areolar tissue
Contains smaller capillaries, lymphatics, and sensory
neurons
Has dermal papillae projecting between epidermal ridges
 The Reticular Layer
Consists of dense irregular connective tissue
Contains larger blood vessels, lymphatic vessels, and nerve
fibers
Contains collagen and elastic fibers
Contains connective tissue proper

22. An inflammation of the papillary layer
Caused by
 infection, radiation, mechanical irritation, or chemicals
(e.g., poison ivy)
Characterized by
itch or pain
Characteristics
Strong, due to collagen fibers
Elastic, due to elastic fibers
Flexible

23. Hair
Papillary
layer
Reticular
layer
Cutaneous
plexus
Papillary
plexus
Epidermal
ridges
Dermal
papillae
Capillary loop
of papillary
plexus

24. The Hypodermis (Subcutaneous Layer)
Lies below the integument
Stabilizes the skin
Allows separate movement
Made of elastic areolar and adipose tissues
Connected to the reticular layer of integument by
connective tissue fibers
Deposits of Subcutaneous Fat
Distribution patterns determined by hormones
Reduced by cosmetic liposuction (lipoplasty)

26. Accessory organs and glands of the skin:
Hair :
Nails
Sweat glands:
Sebaceous glands:

27. The Hair Follicle
 Hair follicles are the organs that form the hairs.
Hair follicles are the organs that form the hairs.
Located deep in dermis.
Produces nonliving hairs.
Wrapped in a dense connective tissue sheath.
Base is surrounded by sensory nerves (root hair plexus).
Control bacteria

28. Exposed
shaft
of hair
Sebaceous
gland
Arrector
pili
muscle
Connective
tissue sheath
Root hair
plexus
Accessory Structures of Hair
Arrector pili
Involuntary smooth muscle
Causes hairs to stand up
Produces ―goose bumps‖
Sebaceous glands
Lubricate the hair

29. Regions of the Hair
Hair root
Lower part of the hair
Attached to the integument
Hair shaft
Upper part of the hair
Not attached to the
integument
Boundary
between
hair shaft
and
hair root
Arrector
pili muscle
Hair shaft
Sebaceous
gland
Hair root
Connective
tissue sheath
Hair bulb
Hair matrix
Hair papilla

30. Nails
Protect fingers and toes
Made of dead cells packed with
keratin
Metabolic disorders can change
nail structure
Nail Production
Occurs in a deep epidermal fold
near the bone called the nail root
Free edge
of Nail
Body of
Nail
Laternal
Nail fold
Lunula
Eponychium
(cuticle)

31. Structure of a Nail
Nail body
The visible portion of the nail
Covers the nail bed
Lunula
The pale crescent at the base of the nail
Sides of nails
Lie in lateral nail grooves
Surrounded by lateral nail folds

32. Eponychium
Proximal nail fold
Nail root
Lunula Nail body
Epidermis Dermis
A longitudinal section
Phalanx Hyponychium

33. Sweat and Sebaceous glands:

34. A. Sweat Glands:
Situated in the dermis
Excretes urea, salt water and other ions in the form of sweat
• Eccrine sweat glands:
-Mostly found in palms and soles
-Secretion is thin and watery for temperature regulation under control of Automatic
Nervous System.
• Apocrine sweat glands:
-Located in axillary and pubic region
-ducts empty in hair follicles
-secretion is more viscous( fats and proteins) than eccrine glands
-activated by sex hormones and sympathetic autonomic nervous system

35. B. Modified sweat glands:
Ceruminous glands:
-Located in the external ear canal
-Secretes wax (cerumin)
Mammary glands:
-Milk producing and is most dominant in female
-secrets milk after parturition
C. Sebaceous glands:
-Located next to hair follicles and oily secretion called sebum
-sebum composed of triglycerides, cholesterol, proteins and electrolytes.
-inhibits bacterial growth, lubricates hair shaft and conditions the skin
-influenced by sex hormones

36. Thermoregulatory function of the skin:
Physics of Heat Loss from the Body:

37. “Set-Point” for Temperature Control
●Criticalbodycore temperature isabout36.8°C to 37.1°C (98.8°F)
●Drasticchangesoccurin the rates ofboth heatlossandheatproduction.
●Attemperaturesabovethislevel, the rate ofheatlossisgreater thanthat
ofheatproduction, sothe bodytemperature fallsandapproaches the
37.1°C level.
●Attemperaturesbelow thislevel, the rate ofheatproduction isgreater
thanthat ofheatloss, sothe bodytemperature risesandagain
approachesthe37.1°Clevel.
●Thiscrucialtemperature leveliscalledthe “set-point”ofthe temperature
control mechanism.
●Thatis, allthe temperature control mechanismscontinuallyattempt to
bringthebodytemperature backto thisset-point level.

38. Mechanism:
-The thalamus is the temperature regulating center responsive to the
temperature of the circulating blood.
-Controls through autonomic nerve stimulation of the sweat glands
and peripheral blood vessels.

40. Pigmentation:
Skin pigmentation determined by the following pigments:
1. Melanin:
dark skinned people produce more melanin although having similar
amounts of melanocytes which is stimulated by the exposure to sunlight and
protects from UV radiation.
2.Carotene:
-gives yellow or orange skin color
3. Bilirubin and biliverdin:
-products of degradation haemoglobin and gives yellow skin color
4. Hemoglobin:
-gives pinkish color to fair and dark color in black skin.

41. Healing of wounds
It is defined as a living body response in an attempt to restore the
normal structure and function which include regeneration and repair
of body parts simultaneously.

42. Factors delaying wound healing
- Infection
- Poor blood supply
- Presence of foreign body
- Mobilization of wounded part
- Age slow in old age
- Nutritional deficiency
- Diabetes
- Bleeding disorders
Complications:
-Epidermal cyst
-Scar formation
-Infection may occurs
-Neoplasia may develop if untreated for long time

43. Burns:
The injury which is caused by dry heat is called burns and by moist
heat is called scalds.
Causes of burns:
Dry heat: fire, flame, piece of hot metal
Moist heat: boiling water, steam, hot oil
Electricity; electric currents and lightning
Radiation: burns due to radium and deep X-ray.
CLASSIFICATION:
Erythema: results from vasodilation due to heat with sign of
inflammation.
Superficial burns: only superficial layer is lost and very painful due
to exposure of nerve ending.
Deep burning: whole skin is lost and less painful due to nerve
ending burning. Skin grafting is needed.

44. Estimation of burns
The percentage of body surface burn can be estimated by Wallace
rule of NINE

45. Skin disorders
A. Inflammatory disorders:
-viral infections:HPV (human pailoma virus) causes warts
herpes virus causes chicken pox, shingles in the skin
-Bacterial infections: impetigo and cellulities
-Fungal infection: Ringworm and Tinea pedis
B. Non- Inflammatory disorders:
-Eczema and dermatitis
-psoriasis
-Malignant tumors: basal cell carcinoma, malignant melanoma,
Kaposi’s sarcoma etc.

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