Transcript Skin ppt

I. Membranes
Classified by tissue types.
1. Epithelial Membranes (layer of epithelia and
connective tissue) = Simple organ
a. Cutaneous Membrane (skin) composed of
stratified squamous and dense connective
tissue. Unique because it is primarily a “dry”
membrane.
b. Mucous Membrane (mucosa) composed
of epithelia and loose connective tissue.
i. Membrane lines body cavities that open to the exterior
(digestive, respiratory, urinary and reproductive)
ii. A “wet” membrane continuously bathed in secretions
(mucus or urine).
iii. Cell types vary (squamous or columnar) typically
specialized for secretion (mucus) or absorption
(digestive tract).
c. Serous Membranes (serosa) composed
of simple squamous and aerolar
connective tissue.
i. Line body cavities that are closed
to the exterior (except dorsal cavity
and joints)
ii. Occurs in pairs:
1. Layer that lines the body
cavity is known as the parietal
layer
2. Layer that lines the body
organ is the visceral layer
3. Fluid between layers
iii. Function of membrane is to decrease friction between organs.
Ex. Heart and lungs, stomach and intestine.
iv. Location of membrane can dictate name.
Ex. Pleura around lungs; pericardium around heart, peritoneum in
abdominal cavity.
2. Connective Tissue
Membranes/Synovial Membranes
(composed of soft aerolar tissue)
a. Lines:
i. fibrous capsules of
your joints,
ii. bursa (sacs of
connective tissue at some
joints),
iii. tendon sheaths
b. Protects against friction
between moving parts of the
body.
• Friction is the force resisting the relative
motion of solid surfaces, fluid layers, and
material elements sliding against each
other.
Cool Skin Facts
• Your skin weighs around 9 pounds
• You lose 30-40 thousand skin cells each
minute (around a billion in a day) Hi! I live in
your
• These mites live in your
eyelashes!
Eyelash follicles!
II The Integument System Structure (skin and its derivatives)
A. Epidermis – top most superficial layer
1. Composed of stratified squamous epithelial
2. Avascular and not innervated (no nerves)
3. Different cell types:
a. Keratinocytes – produce keratin helps with
waterproofing of the skin; these cells are lost
through friction.
b. Melanocytes – produce melanin (primary skin
pigment), found in the lowest level of epidermis.
Function is to protect the DNA in the nucleus
from the UV radiation of the sun.
Amount and kind of melanin determine skin
color.
c. Immune system cells in lower layers for early
detection (called Langerhans cells)
4. Layers of epidermis
a. Stratum corneum – most
superficial layer, numerous
cell layers (20 to 30); cells
are dead (cornified) and
flake off easily. Major
protective layer.
b. Stratum Lucidum – Only
present on palms and soles
of your feet. Cells are clear
and dead (too far to receive
nutrients and oxygen)
c. Stratum Granulosum
d. Stratum Spinosum
e. Stratum
Basale/Germinativum –
layer of rapid cell division
How tatoos work.
"Come, Let's Get Sun Burned":
· From superficial to deep:
Corneum
Lucidum
Granulosum
Spinosum
Basale [Germinativum]
2. Dermis – Intermediate layer and the
thickest “your hide”
1. Composed of dense fibrous connective
tissue
2. Primary function is to hold the body
together therefore it is very strong and
stretchy
3. Composed of two layers
a. Papillary layer – upper/superficial
layer
i. Contains dermal papillae (ridges
that extend up into the dermis)
these are the ridges of your
fingerprints. Increase friction.
ii. Capillaries extend into the
ridges to provide nutrients to
stratum basal layer by diffusion.
iii. Location of pain receptors
(Meissner’s corpuscles)
b. Reticular layer – thicker
layer of the dermis
i. Contains blood vessels,
sweat and oil glands,
pressure receptors
(Pacinian corpuscles),
phagocytes (immune cells)
and collagen and elastic
fibers.
a. Collagen – help keep
skin hydrated
b. Elastic – help with skin
“stretchyness”
c. Hypodermis – Deepest layer of skin
1. Composed of adipose tissue
2. Anchors the two other layers
to underlying organs also
insulate and act as a shock
absorber.
Skin Layer Review
"Come, Let's Get Sun Burned":
· From superficial to deep:
Corneum
Lucidum
Granulosum
Spinosum
Basale [Germinativum]
III Appendages of the Skin – Arise from the epidermis
(stratum basal)
A. Cutaneous Exocrine (have a duct) glands
1. Sebaceous Gland / Oil Glands
a. Found everywhere except palms of
hands and feet.
b. Duct empties into a hair follicle.
c. Sebum is the product excreted
composed of oils, chemicals that
kill bacteria and fragmented cells.
d. Function to lubricate the skin and
hair and protection against microbial
invasion.
2. Sudoriferous / Sweat Glands
a. 2.5 million per person
b. Two types:
i. Eccrine Glands – more numerous and found
everywhere; primary excretion is sweat (water, salts,
vitamin C, metabolic wastes, and lactic acid) Secretion
empties out onto the skin through a pore
ii. Apocrine Glands – Only found in axillary and
genital areas; empty into hair follicle; secretions contain
fatty acids and proteins (causes body odor when
microbes digest); function not yet clear.
The lovely mites
that live in our
eyelash follicles!
B. Hair and Hair Follicle
1. Layers of hair – cuticle (outer most, looks like
shingles on a roof), cortex (area of color) and medulla
(core, different pattern in each species)
2. Types of hair:
a. Vellus hair – “peach fuzz” covers the entire
body.
b. Terminal hair – darker hair on head, eye lashes,
eye brows, pubic area, etc…
c. Function of the hair – protection (eye lashes, nose hairs,
etc..)
d. Hair follicle
IV Function of the integument (the best coat you’ll ever
wear)
A. Thermoregulation – maintaining proper body
temperature
1. Capillaries in the dermis can dilate (get bigger)
releasing heat from the skin (red and swollen)
causing a flushed appearance; or become
restricted and redirect blood flow
away from skin to more vital parts of the body (why
your skin feels cold)
2. Sweat glands -release of water from sweat
results in evaporative cooling.
B. Physical and Chemical Damage - bumps, cuts,
scrapes, burns.
a. Keratinized cells in upper epidermis
b. Nerve receptors that alert central nervous
system to a problem
C. Microbe damage – bacteria
1. “acid mantle” secretions of epidermis slow/prevent
bacterial growth
2. Phagocytes in dermis that engulf pathogen (disease
causing microbes)
D. Desiccation – drying out
1. Keratinized epidermal cells- waterproof
E. Excretion
1. Sweat – uric acid, heat, other toxins and chemicals.
2. Pheromones – through apocrine sweat glands
3. Oil – through sebaceous glands
F. Synthesis
1. Vitamin D (modified cholesterol and sunlight) helps
with calcium absorption in the digestive tract.
2. Proteins necessary for immunity.
G. UV radiation
1. Melanin protecting DNA in nucleus from mutations.
Fingerprints
• Arch
•
Whorl
Double loop
Eccrine vs. Apocrine Glands
Use your notes to explain their location,
secretion, functions
Question of the Week
Why do we have fingernails?
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“We have fingernails because we're primates," said John Hawks, a
biological anthropologist at the University of Wisconsin-Madison.
“Fingernails distinguish primates, they are essentially flattened forms
of claws to grab onto things, to climb things, to scratch things, and to
dig holes."
While claws would have provided excellent grip as our mammalian
ancestors clambered up large tree trunks, they would have been a
nuisance for larger-bodied primates trying to grasp smaller branches
while scrambling across tree canopies for fruits. Rather, primates
developed broader fingertips made for grasping.
Nails serve as a visual advertisement of a person's health, he said.
For instance, malnutrition can change the coloring of nails.
small pits in fingernails can signal the skin condition psoriasis.
Spoon-shaped--- anemia
A healthy nail has a specific shape—slightly raised in the middle,
then curving down a bit at the tip.
Dry and brittle it’s possible for an under-active thyroid to cause both
dry skin and brittle nails
Yellow-When all of the nails turn yellow it can be a sign of lung
disease or diabetes,”
White spots- nail injury or can be ZINC defeciency, or air spaces in
nail plate
V Development of the Integument System
A. Fetal Development and Birth
1. Lanugo – downy hair that covers the fetus’s
body and is typically shed by birth.
2. Vernix caseosa – white secretion by the
sebaceous glands which protects the baby’s skin
in the uterus.
3. Milia – accumulation of sebaceous glands on
nose and forehead, typically disappear by 3rd
week.
4. Seborrhea – “cradle cap” formed from
overactive sebaceous glands forming raised
lesions that crust over and slough off.
5. As baby developed skin becomes thicker and
moist and more subcutaneous fat is deposited.
B. Adolescence
1. Sebaceous glands increase their activity and acne (infection of
sebaceous gland) can appear.
a. White head – sebaceous gland blocked by
sebum
b. Black head – when accumulated material oxidizes
and dries
c. 20’s and 30’s your skin is the best it will ever look!
C. Old Age
1. Subcutaneous fat deposits decrease (intolerance of cold due to lack
of insulation and thinness of skin can lead to increase in bruising)
2. Decrease oil production and fewer collagen fibers contribute to
overall decrease in moisture level of skin.
3. Sagging is caused by the loss of elasticity of the elastic fibers in the
skin.
4. Overexposure to sun can lead to increase incidence of skin cancer
(accumulation of mutations over the years)
5. Hair follicle numbers decrease by 1/3 by the age of 50 resulting in
hair loss (alopecia) and melanocytes can stop producing melanin
in the follicle and the hair appears “gray”
(due to a delayed action gene)
D. How can we reverse this aging trend?
1. Stay out of the sun /use sunscreen
2. Good balanced diet (antiaging foods- blueberries,
nuts, brocolli, green leafy veggies, garlic, tomatoes, soy
beans, prunes, etc.)
3. Plenty of water
4. Cleanliness / good hygiene
In Raynaud's disease, smaller arteries that supply
blood to your skin narrow, limiting blood circulation
to affected areas.
VI Homeostatic Imbalances of the Skin (there are over
1000)
A. Changes in color
1. Redness /Erythema – dilation of capillaries in
the skin
2. Blanching/Pallor – pale skin can be indicative of
anemia, emotional stress, low blood pressure.
3. Jaundice – yellowing of skin from a liver
disorder (not breaking down bile properly and the
pigments are circulated through the blood)
4. Bruises – blood has escaped the vessels and
clotted in the tissues (hematoma)
B. Blockage in circulation results in cell death and therefore
tissue death. Ex. Bed sores (decubitis ulcer) result
when patients are bedridden, weight of the body puts
pressure on the skin and circulation is impaired in that
area.
C. Blisters - skin is exposed to constant friction causing the
dermis and epidermis to separate
D. Attack by bacteria, virus and/or fungus or allergy.
Symptoms and effects to skin vary with cause. (read
over pg. 107 for specific types) Ringworm, caused by a
fungus in middle picture and impetigo caused by
bacteria in third picture.
E. Burns – tissue damage and cell death caused by
radiation, electricity, chemicals or heat
1. Dangerous because:
a. Loss of fluids (dehydration and electrolyte
imbalance)
b. Exposure to pathogens and risk of infection
(exposed area and depressed immune system)
2. Three types (classified by severity):
a. Partial Thickness Burns
1)First Degree Burn – Only epidermis is
damaged; symptoms are redness and
swelling in the area. Heals usually within
2 to 3 days.
2) Second Degree Burn – Epidermis and
upper layer of dermis affected; blisters
will appear; regeneration can occur (little
scarring)
2. Full Thickness Burns
Third Degree Burn – entire thickness of skin is
burned; area is charred (black) or blanched;
nerve endings destroyed (not initially painful);
regeneration not possible, skin must be
grafted.
Burns are considered critical if the following
criteria are met:
25% of body has 2nd degree burn
10% of body has 3rd degree burn
3rd degree burns on face and hands (loss of
mobility due to lack of regeneration and
proximity to respiratory system)
Look over the Rule of 9’s on page 108.
F. Skin Cancer
1.Cells divide uncontrollably and the cancer can metastasize (move
to other areas of the body); growth can also be benign such as
warts.
2. Factors that can predispose a person to skin cancer: exposure
to UV radiation (sun), frequent irritations, genetics.
3.Types:
Basal Cell Carcinoma – least malignant; most common; cells stop
producing keratin and invade the dermis. Relatively slow growing
and 99% full cure if lesions removed surgically. Sun induced!
Squamous Cell Carcinoma – Arise from stratum spinosum layer;
lesion is scaly in appearance; appears on scalp, ears, tops of
hands and lower lips; grows more rapidly and can metastize.
Malignant melanoma – Cancer of melanocytes; often deadly
metastases quickly; survival 50% with early detection.
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Rule for detection – ABCD Rule
Asymmetry of the lesion
Border irregularity (not smooth)
Color changes and different colors in same area
Diameter is larger than 6mm (pencil eraser
Skin Disease Assignment
Choose a skin disease from the list provided and research with a
partner.
Research and create a presentation in KEYNOTE on the iPads.
KEYNOTE is so user-friendly! Let me know if you need help getting
started.
You will be doing a 5 min. presentation to the class tomorrow! See
rubric for grading information.
• Name of skin disease:
1 points
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Skin structures/ layers affected 5 points
•
Cause(s)
5 points
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Signs and symptoms :
5 points
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Treatments, cures, prevention: 5 points
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Illustrations, pictures:
5 points
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Bibliography (min.2 sources): 4 points