1. Integumentary System

2. Anatomy A-Day 11/21/16 Bellringer
What is the body membrane layer that is the outermost layer (skin)?
What membrane surrounds joints and is composed of only areolar connective tissue?
Agenda
Bellringer
Skin Structure Notes
Skin Label and Diagram
Skin Sensory Lab

3. Anatomy A-Day 11/21/16 Bellringer
What is the body membrane layer that is the outermost layer (skin)?
Cutaneous
What membrane surrounds joints and is composed of only areolar connective tissue?
Synovial membrane
Agenda
Bellringer
Skin Structure Notes
Skin Label and Diagram
Skin Sensory Lab

4. Body Membranes
Body membranes cover surfaces, line body cavities, and form protective sheets over organs
Two major groups:
Epithelial membranes – cutaneous (skin), mucous, and serous membranes
Connective tissue membranes – synovial membranes

5. Epithelial Membranes
Epithelial membranes – covering and lining membranes
Contain an epithelial sheet, but it is always combined with a connective tissue layer
2 tissues = These membranes are actually simple organs

6. Cutaneous Membrane = Skin
Its superficial epidermis is composed of keratinizing stratified squamous epithelium.
Underlying dermis is mostly dense (fibrous) connective tissue.
Exposed to air = dry membrane

7. Mucous Membrane = Mucosa
Composed of epithelium resting on loose connective tissue called lamina propria.
Lines all body cavities that open to exterior
Varied types
Stratified squamous epithelium in mouth, esophagus
Simple columnar epithelium in digestive tract
Wet membranes bathed in secretions or urine
Adapted for absorption or secretion

8. Serous membrane = serosa
Layers of simple squamous epithelium resting on a thin layer of areolar connective tissue
Line body cavities that are closed to exterior
Occur in pairs:
Parietal layer lines the wall of the ventral cavity
Visceral layer covers the outside of those organs
Layers separated by serous fluid, which allows organs to slide without friction (heart, stomach)

9. Serosa
Serosa lining the abdominal cavity and covering its organs = peritoneum
Membrane surrounding lungs = pleura
Membrane around the heart = pericardium

10. Synovial Membranes
Composed of soft areolar connective tissue and contain no epithelial cells.
Line the fibrous capsules surrounding joints and tendon sheaths
Secrete lubricating fluid to cushion organs during muscle activity

11. Tattoos
Tattoos are made by using a needle to deposit pigment in the dermis.
Risk of Hepatitis C is 15x higher in people who have tattoos…

12. Cutaneous Membrane = Skin
Skin and its glands (sweat, oil), along with hair and nails, make up the integumentary system
Integument (covering):
keeps water and other molecules in the body
Insulates and cushions body organs
Protects body from damage.
Uppermost layer of skin is full of keratin and is cornified (hardened) to help prevent H2O loss.

13. Regulation and Reception
Capillary network and sweat glands in skin regulate heat loss
Urea, salts, and water are lost when we sweat
Manufactures proteins - immunity
Synthesizes Vitamin D (sunlight converts cholesterol in skin into vit. D).
Cutaneous sensory receptors are located in skin – sense pain, pressure, temperature, touch

14. Skin Structure Two kinds of tissue in skin
Epidermis (outer) – stratified squamous epithelium, keratinizing (can become hard)
Dermis (inner) – dense connective tissue
Subcutaneous layer (hypodermis) – below dermis, adipose tissue, anchors skin to organs.

15. Skin Structure
Subcutaneous layer – shock absorber and insulation from extreme T changes
Thicker in women than in men (adipose tissue)

16. Epidermis Five layers / strata:
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
Epidermis is avascular (no blood supply)
Ex: shaving is cutting off cells w/ no blood (usually)

17. Stratum Basale
Most cells of epidermis are keratinocytes (keratin cells) which produce keratin
Keratin –protein that makes epidermis tough
Deepest layer of epidermis / closest to dermis
Stratum basale constantly undergoing mitosis, a.k.a. stratum germinativum
Daughter cells pushed upward into superficial layers

18. Epidermis New cells become increasingly flatter and full of keratin
Stratum Spinosum – relatively thick
Stratum granulosum – cells granular

19. Epidermis As new cells die they form the stratum lucidum (no O2)
Only present where skin is hairless and thick (palms of hands, soles of feet)
Stratum corneum – ¾ of epidermal thickness
Cornified or horny (cornu = horny) cells, completely keratinized (…and dead)

20. Melanin Melanin is a pigment that ranges from yellow to brown to black
Produced by melanocytes, found in stratum basale.
Everyone has same number of melanocytes
Complexion determined by quantity of melanin produced
Heredity – genes specific for melanin production; mutant genes can cause lack of melanin

21. Albinism
Albinism results when genetic changes result in a lack of pigment (melanin) production
Can have eye problems (light scattering, optic nerve problems)

22. Dermis = your hide Two major regions
Papillary – upper dermal region
Dermal papillae (papill=nipple) – house pain receptors, send nutrients to epidermis, form fingerprints
Reticular – deepest skin layer
Contains blood vessels, sweat and oil glands, and pressure receptors (Pacinian corpuscles)
Collagen (toughness) and elastic (stretch when growing) fibers found in dermis
Many receptors for nervous system

23. Skin Appendages
Cutaneous glands – exocrine. Release secretions to skin surface via ducts.
Sebaceous (oil) glands – often open into hair follicles. Everywhere but palms and soles.
Secrete sebum – oil that keeps skin soft and kills bacteria. Increased amount in adolescence

24. Acne = infection of sebaceous gland
When sebaceous gland’s duct is blocked by sebum, a whitehead appears on skin surface
If the material accumulates and dries it darkens to form a blackhead.
Sebaceous cysts occur when keratin blocks the sebaceous gland and inflammation occurs.
Sebaceous Cyst

25. Sweat Glands
Sweat (Sudoriferous) Glands – more than 2.5 million per person. Two types:
Eccrine glands – most numerous, all over body. Produce sweat (water plus salts and vitamins)
Sweat is acidic (pH 4-6) so inhibits growth of bacteria
Apocrine glands – confined to armpits and genital areas of the body. Secrete fatty acids and proteins
Function unclear but activated during stress, pain, sex

26. Hair Millions of hairs Minor protection:
Head bumps
Eyelashes
Nose hairs
Early humans – provided insulation from cold weather

27. Hair Produced by hair follicle Flexible epithelial structure
Root in follicle
Shaft projects from skin
Matrix (growth zone) of hair bulb at end of follicle
Pigment made by melanocytes

28. Nails Scale-like modification of epidermis Free edge
Body (visible portion)
Mostly nonliving keratinized cells