F. Y. B. Pharm Sem I: Unit II: 1. Integumentary System
1. INTEGUMENTARY SYSTEM
PRESENTED BY:
MS. SHRADDHA MAHADEV PARAB
ASSISTANT PROFESSOR
YASHAWANTRAO BHONSALE COLLEGE OF PHARMACY, SAWANTWADI
Yashawantrao Bhonsale College of Pharmacy, Sawantwadi
3. INTRODUCTION TO INTEGUMENTARY SYSTEM
The skin is the largest organ of the human body
Accessory structures include: - Hair, nails,
sebaceous glands, and sudoriferous
Is composed of three layers:
1) Epidermis (Epi - above or outer)
2) Dermis
3) Subcutaneous layer (Sub - below)
Impulses from the skin are interpreted in the
parietal lobe of the brain - Parietal refers to a layer
away from the organ
4. INTEGUMENTARY SYSTEM
The Integument
Is the largest system of the body: 16% of body weight, 1.5 to 2m² in area,
The integument comprises two parts:
1. Cutaneous membrane
a. Epidermis- Superficial epithelium
b. Dermis - underlying CT with blood supply
2. Accessory structures
a. Hair
b. Nails
c. Exocrine Glands
6. PROTECTION
Intact skin serves as a protective
barrier to our body
1. First line of defense against
Bacteria
Viruses
2. Protects underlying structures
from Ultraviolet (UV) radiation
Dehydration
3. Vitamin D production: Needed
for calcium absorption
7. ABSORPTION
The skin is a route by which substances
can enter the body.
Transdermal absorption can administer
medications such as motion sickness
medications and hormonal therapies.
Medication lotions are applied to the
skin for quick absorption and surface
treatment.
Transdermal patches and medication
pastes have time-release properties
that allow medications to be absorbed
through the skin at a slower process
rate.
8. REGULATION
1. 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
2. Excretion
Small amounts of waste products are lost through perspiration
9. SECRETION
The skin contains millions of sudoriferous
glands that produce sweat and sebaceous
glands that produce oil for skin lubrication.
Perspiration is a mixture of salt and water
with other chemical compounds.
Accumulated sweat produces body odor and
bacteria.
Sebaceous glands produce sebum, which
protects the body from dehydration.
10. SENSATION
The skin has millions of microscopic nerve
endings that act as sensory receptors.
Sensory reactions include responses to
pressure, traction, heat, cold, pain, and
other sensations.
Nerve endings send information to the
brain for the appropriate response to
sensations.
The integumentary and nervous systems
work together for the function of
sensation.
11. STRUCTURE OF SKIN
The Epidermis Epithelial tissue
Dermis Dense connective tissue
proper - irregular
Hypodermis OR Subcutaneous
tissue- loose connective tissue
proper and adipose tissue
12. 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 and are the most abundant cells in the epidermis
Thin Skin: Covers most of the body and has four layers of keratinocytes
Thick Skin: Covers the palms of the hands and soles of the feet and has five
layers of keratinocytes
13. STRUCTURES OF THE EPIDERMIS
The five strata of keratinocytes in thick skin
From basal lamina to free surface
1. Stratum corneum
2. Stratum lucidum
3. Stratum granulosum
4. Stratum spinosum
5. Stratum basale
14. A. STRATUM BASALE
It is attached to the basement membrane by hemidesmosomes
Forms a strong bond between epidermis and dermis.
Forms epidermal ridges. Eg fingerprints
It is the lowermost layer of epidermis
It is the single cell layer, thick in nature
Consists of cells that only get adequate nutrition and oxygen by diffusion from
tissues below
These are the actively dividing cells
bordered below by basement membrane
15. B. 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 the thickness of the epithelium
Contain dendritic (Langerhans) cells, active in immune response.
16. C. STRATUM GRANULOSUM
the "grainy layer"
Three to five layers of keratinocytes
Three to five rows of flattened keratinocytes, in which organelles are beginning to
degenerate;
cells contain the protein keratohyalin, which converts tonofilaments into keratin,
and lamellar granules, which release a lipid-rich, water-repellent secretion.
17. D. STRATUM LUCIDUM
Present only in the skin of fingertips, palms, and soles;
consists of three to five rows of clear, flat, dead keratinocytes with large amounts
of keratin.
18. E. STRATUM CORNEUM
the "horn layer"
Exposed surface of skin
15 to 30 layers of keratinized cells
Water resistant
Shed and replaced every 2 weeks
19.
20. 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
21. o The Papillary Layer
Consists of areolar tissue with thin collagen and fine elastic fibers
Contains smaller capillaries, lymphatics, and sensory neurons
Has dermal papillae projecting between epidermal ridges
o The Reticular Layer
Consists of dense irregular connective tissue
Contains larger blood vessels, lymphatic vessels, and nerve fibers
Contains collagen and elastic fibers
Spaces between fibers contain some adipose cells, hair follicles, nerves,
sebaceous glands, and sudoriferous glands.
22.
23. THE STRUCTURAL BASIS OF SKIN COLOR
Melanin, hemoglobin, and carotene are three pigments that impart a wide variety of
colors to skin.
The amount of melanin causes the skin’s color to vary from pale yellow to reddish
and brown to black.
24. HYPODERMIS
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)
25.
26. HAIR: STRUCTURE OF HAIR
A. The Hair Follicle:
o Hair follicles are the organs that form the hairs.
o Located deep in the dermis.
o Produces nonliving hairs.
o Wrapped in a dense connective tissue sheath.
o The base is surrounded by sensory nerves (root hair plexus).
27. STRUCTURE OF HAIR
B. Accessory Structures of Hair:
Arrector pili
o Involuntary smooth muscle
o Causes hairs to stand up
o Produces “goosebumps"
o Sebaceous glands Lubricate the hair
28. STRUCTURE OF HAIR
Regions of the Hair:
A. Hair root
o Lower part of the hair
o Attached to the integument
B. Hair shaft
o Upper part of the hair
o Not attached to the integument
29. Hair Shaft Structure
Medulla: Core, dead cells contain soft keratin and
air to provide flexible
Cortex: Middle layer, dead cells contain hard
keratin to provide stiffness
Cuticle: Outermost, overlapping dead keratinized
cells form the shiny surface
30. FUNCTIONS OF HAIRS
Head:
o UV protection
o Cushion from trauma
o Insulation
Nostrils, Ear canals, Eyelashes: Prevent entry of foreign material
Body Hair: sensory detection
Root hair plexus: Sensory nerves at the base of the hair follicle that detect slight
movement of hair
Arrector pili muscle: Attached to every hair follicle Contract to stand hair perpendicular
to the skin surface
31. NAILS
Protect fingers and toes
Made of dead cells packed with keratin
Metabolic disorders can change nail structure
32. STRUCTURE OF NAILS
Nail body
o The visible portion of the nail
o Covers the nail bed
Lunula
o The pale crescent at the base of the nail
Sides of nails
o Lie in lateral nail grooves
o Surrounded by lateral nail folds