Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

Integumentary System: Skin & Body
Membranes

Chapter 4

Body Membranes
Function of body membranes
1
...


Protect body surfaces

3
...
Epithelial membranes
2
...
1

Serous Membranes
Specific serous membranes
▪ Peritoneum

▪ Abdominal cavity
▪ Pleura

▪ Around the lungs
▪ Pericardium

▪ Around the heart

Connective Tissue Membrane
Synovial membrane
▪ Connective tissue only
▪ Lines fibrous capsules surrounding
joints
▪ Secretes a lubricating fluid

Figure 4
...


Mechanical damage
▪

Protection of internal structure

2
...


Bacterial damage
▪

Prevention from entry of disease causing microorganisms

4
...


Ultraviolet radiation – pigmentary protection

6
...


Aids in heat regulation – thermal regulation

8
...


Synthesizes vitamin D

10
...


Stratum basale
▪

Cells undergoing mitosis

▪

Lies next to dermis

▪

Gets nourishment through diffusion

2
...


Stratum grandulosum (keratinization)

4
...


Occurs only in thick skin (palms & soles)

Stratum corneum (prevents desication)
▪

Shingle-like dead cells, 20-30 layers thick

▪

Rubs and flakes off constantly (desquamation)

▪

Replaced by cells from stratum basale

The epidermis is
completely renewed
every 25 to 45 days

Dermis
Two layers:
▪ Papillary layer (upper)
▪ Projections called dermal papillae
▪ Pain receptors
▪ Meissner’s corpuscles (touch)
▪ Capillary loops

▪ Reticular layer
▪ Criss-crossing collagen meshwork
▪ Sweat and oil glands

▪ Deep into the dermis is the
hypodermis or subcutaneous
tissue

▪ Nerve receptors

▪ Not part of the skin!!

▪ Pacinian corpuscles (Lamellar
corpuscles): detect deep pressure

▪ Anchors skin to underlying organs

▪ Blood and lymph vessels

▪ Hair follicle and smooth muscle

▪ Composed mostly of adipose tissue
▪ Also contains blood and lymph vessels,
base of hair follicles and sweat glands

Skin Structure

Epidermis

meissner’s corpus
Papillary
free nerve ending

sweat gland

reticular

sebaceous gland
arrector pili muscle

lamellar corpuscle

hair root

Appendages of the Skin
Sebaceous glands
▪ Produce oil (sebum);a mixture of fats,
waxes and hydrocarbons
▪ Lubricant for skin making it soft and
smooth; prevent desication
▪ Numerous on face , scalp, chest

Widely distributed except for palm
of hands and soles of feet

▪ Kills bacteria
▪ Most with ducts that empty into hair
follicles
▪ Glands are activated at puberty

Hyperactivity leads to seborrhea

Appendages of the Skin
Sweat (Sudoriferous)glands
▪ Widely distributed in skin
▪ Two types
▪ Eccrine (Merocrine)
▪ Open via coiled ducts to pore on skin surface
▪ 99% water, 1% salts and Vit C; meant for temperature regulation

▪ Apocrine
▪ Ducts empty into hair follicles
▪ Found armpits (axillary region), areolae of nipples, and genital region
▪ Activate at puberty; unlike eccrine gland that respond to heat, these
respond to stress and sexual activity
▪ Contains fatty acids and proteins; may act as phermones
▪ Other modified apocrines include mammary and ceruminous glands

Appendages of the Skin (cont’d)
Hair
▪ Has lost much of it’s usefulness
▪ Used to keep our ancestors warm
Now…
▪ Protects head from bumps
▪ Shields eyes
▪ Keeps particles out of respiratory system

Associated Hair Structures
Hair

Figure 4
...
7b

Appendages of the Skin
Nails
▪ Scale-like
modifications of the
epidermis
▪ Heavily
keratinized
▪ Stratum basale
extends beneath the
nail bed
▪ Responsible for
growth
▪ Lack of pigment
makes them colorless

Skin Colour
▪ M_________ are mostly in the
stratum basale

▪ We all have similar amounts of melanocytes

▪ BUT in some, melanocytes produce
▪ Pigment (m________) produced
more or less melanin
by melanocytes
▪ Amount of melanin produced depends upon
▪ Color is yellow to brown to black
genetics and sometimes exposure to sunlight
▪ Amount of melanin determines
colour
▪ Human skin varies from dark
brown to nearly colorless

Some individuals have
melanocytes that produce very
little or no melanin

Other Skin Color Determinants
▪ Melanocytes
▪ Yellow, brown or black pigments
▪ Carotene
▪ Orange-yellow pigment from some
vegetables
▪H
▪ Red coloring from blood cells in dermis
capillaries
▪ Oxygen content determines the extent of red
coloring

UV radiation and Skin
▪

Small amounts of UV are good for people
▪

▪

Essential in the production of vitamin D

Prolonged exposure to UV radiation may
result in acute and chronic health effects:
1
...
Actinic keratoses are skin growths that
occur on areas exposed to the sun
3
...
Skin Cancer

▪

All people are susceptible to these problems
regardless of skin darkness

Tanning, Burning; Whatever
▪ Caused by UV rays
from the sun
▪ UVB affect epidermis
causing burns
▪ UVA penetrates
dermis causing tans
▪ UVA ages skin
▪ UVB causes cancer
▪ Tans are body’s way
of protecting itself (it
produces melanin)

Actinic Keratosis
▪ A scaly or crusty bump that forms on the
skin surface
▪ Also called sun spots, solar keratosis, or
precancerous spots
▪ May come and go
▪ May be the first step to the development
of skin cancer
▪ 10 or 15% of the more active lesions
make progress into squamous cell
carcinomas

Skin Cancer
▪ Cancer—abnormal cell mass
▪ Classified two ways
▪ Benign

▪ Does not spread (encapsulated)
▪ Malignant

▪ Malignant (moves) to other parts of the
body

▪ Skin cancer is the most common type of
cancer

Skin Cancer Types
▪ Basal cell
carcinoma
▪ Least malignant
▪ Most common type
▪ Arises from stratum basale
▪ Most common on face and
neck
▪ A sore that recurs and often
bleeds
▪ Can be scraped and burned
off (curretage and
electrodesication)

Skin Cancer Types
▪ Squamous cell carcinoma
▪ Metastasizes to lymph nodes if not removed
▪ Early removal allows a good chance of cure
▪ Believed to be sun-induced
▪ Arises from stratum spinosum

Skin Cancer Types
▪ Malignant
melanoma
▪ Most deadly of skin
cancers
▪ Cancer of melanocytes
▪ Metastasizes rapidly to
lymph and blood vessels
▪ Detection uses ABCDE
rule

ABCD Rule
▪ A = Asymmetry
▪ Two sides of pigmented mole do not match
▪ B = Border irregularity
▪ Borders of mole are not smooth
▪ C = Color
▪ Different colors in pigmented area
▪ D = Diameter
▪ Spot is larger then 6 mm in diameter
▪ E = Evolution
▪ change in size, shape, colour, etc

Ailments Caused by Homeostatic Imbalances
▪ D_________ - Bed sores
▪ Restriction of blood supply to skin
▪ Cyanosis
▪ Caused by poorly oxygenated haemoglobin
▪ Acne
▪ Blocked sebaceous glands
▪ Seborrhea - cradle cap
▪ Pink raised lesions caused by overactive
sebaceous glands

Common Skin Infections
▪ Infections
▪ Athlete’s foot (tinea pedis)

▪ Caused by fungal infection
▪ Boils and carbuncles

▪ Caused by bacterial infection
▪ Cold sores

▪ Caused by virus

Common Skin Infections
Infections and allergies
▪ Contact dermatitis
▪ Exposures cause allergic reaction
▪ Impetigo
▪ Caused by bacterial infection
▪ Psoriasis
▪ Cause is unknown
▪ Triggered by trauma, infection, stress

Skin Repair (Minor Injury)
Steps:
1
...
Clotting mechanisms are activated
3
...
Dermis is repaired by the activity of stem cells
5
...
Cells of stratum basale begin to divide, migrate to
the edges of scab
7
...
Skin is unable to return to its original condition
2
...
relatively few blood vessels
4
...
Replaced by the fibrous tissue
6
...
g
...




---