Body Bugs
NOVA | Bugs That Live on You
Follicular Mites – found in all hair follicles Dust Mites –
found on your body, your bed, any fluffy surface that you spend time with
Essentials of Human Anatomy & Physiology
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slides 4.1 – 4.32
Seventh EditionElaine N. Marieb
Chapter 4Skin and Body Membranes
Lecture Slides in PowerPoint by Jerry L. Cook
Skin and Body MembranesSkin and Body Membranes
Slide 4.1Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Function of body membranes: 1. Line or cover body surfaces
2. Protect body surfaces
3. Lubricate body surfaces
2 TYPES OF MAIN MEMBRANES
• 1. EPITHELIAL MEMBRANES:
• Cutaneous, mucous, & serous membranes included
• All of these do contain an epithelial sheet However, it is always combined with an underlying layer of connective tissue.
• 2. CONNECTIVE TISSUE MEMBRANES:
• Represented by Synovial Membranes = Areolar Tissue: NO Epithelial Cells
1. 1. Cutaneous MembraneCutaneous Membrane
Slide 4.3Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Cutaneous Membrane = skin A dry membrane & exposed to air
Outermost protective boundary
Composed of: Superficial Epidermis Keratinized stratified
squamous epithelium
Underlying Dermis Mostly dense
fibrous connective tissue Figure 4.1a
2. 2. Mucous Membranes (Mucosa)Mucous Membranes (Mucosa)
Slide 4.4Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Surface is Composed of Epithelium resting on loose connective tissue called Lamina Lamina PropriaPropria. **Type of Epithelial tissue depends on site:
Lines all body cavities that open to the exterior body surface: including repiratory, digestive, urinary, & reproductive tracts.
In all cases, these membranes are “wet” or moist
Often adapted for absorption or secretion: it is NOT a requirement that they secrete mucusFigure 4.1b
3. Serous Membranes (Serosa)3. Serous Membranes (Serosa)
Slide 4.5Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Surface = simple squamous epithelium
Underlying epithelial tissue = areolar connective tissue
Lines open body cavities that are closed to the exterior of the body (opposite of Mucous Membranes)
Serous layers separated by serous fluid
Figure 4.1c
Serous Membrane
**Serous Membranes occur in Pairs**
Perietal Layer Lines a specific portion of the wall of the ventral body cavity
Visceral Layer covers the outside of organs in the cavity (this layer is made from the perietal layer folding in on itself)
Serous MembranesSerous Membranes
Slide 4.6
Specific serous membranes: Peritoneum
Abdominal cavity
Pleura Around the
lungs
Pericardium Around the
heart
** Good Picture to look at is on Page 97 Figure 4.1 C
Connective Tissue MembraneConnective Tissue Membrane
Slide 4.7Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
1. Synovial membrane
Connective tissue only (areolar): NO EPITHELIAL CELLS
Lines fibrous capsules surrounding joints, small sacs of connectiev tissue called Bursae, & Tendon Sheaths
Figure 4.2
Integumentary SystemIntegumentary System
Slide 4.8Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Skin (cutaneous membrane)
Skin derivatives:
Sweat glands
Oil glands
Hairs
Nails
Integumentary Functions
Protection - biological
• Biological – cells – macrophages & Langerhan’s cells engulf invaders.
Protection - mechanical
• Mechanical – physical
• Continuity – skin is made impermeable through the tight junctions & desmosomes
• Keratin – physically blocks the passage of water and water soluble substances
• FYI: Molecules that can pass through your skin:
• Lipid soluble – O2, CO2, ADEK, steroids, nicotine, & other transdermal medications
• Oleoresins – poison ivy & poison oak, etc – you have less than 10 min to wash it off!
Protection - Chemical
• Chemical
• Skin secretions: tears, sweat, oil lower pH and contain lysozyme (chemical that lyses cells)
• Melanin – pigment shield against UV radiation
Excretion
• Limited amounts of nitrogen containing wastes (most is excreted in urine unless you have a kidney disorder in which case urea will be excreted in small amounts through skin)
• Sodium chloride through sweat
• Water through sweat
• Heat through sweat
Homeostasis of Body Temperature
• Heat production – chief determinant is muscle activity
• Heat loss/gain
• 80% of heat transfer is through the skin – the rest is through the mucosa (dogs are opposite!)
• Regulated by vasoconstriction & vasodilation since heat is carried primarily in the water content of the blood (reminder: on page 1 of notes)
Understand what is happening in these diagrams!!
Vitamin D Production
• Vitamin D is important in the uptake of Calcium from the food you eat.
• Ca has to be absorbed from your stomach into the blood to go anywhere
• Cholesterol molecules when exposed to UV light become a Vitamin D precurser
• Precurser becomes active in the liver & kidneys
Sensation – skin receptorsDon’t need to memorize
• Free nerve ending = pain
• Meissner’s corpuscles = discriminating touch, light pressure (think fly on your arm)
• Krause’s – cold
• Ruffini’s – heat
• Merkel Disc – Medium pressure
• Pacinian corpuscle – Deep pressure
See diagram in notes
Skin StructureSkin Structure
Slide 4.10aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Epidermis – outer layer:
Stratified Squamous epithelium
Often keratinized (tough & hardened by keratin)
Dermis:
Dense connective tissue
Skin StructureSkin Structure
Slide 4.10bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Deep to dermis is the hypodermis (Subcutaneous Tissue)
Not part of the skin
Anchors skin to underlying organs
Composed mostly of adipose tissue
Responsible for “curves” on your figure
*Serve as a shock absorber and insulates deeper tissues
Skin Structure page 101 (This is on pg 4 of notes – You need know all of your diagrams!
Slide 4.13b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 4.4
Epidermis – FIGURE 2 - fill in text box on left side of diagram
Slide 4.10a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Epidermis – outer layer – color code brackets
Keratinized stratified squamous epithelium
Avascular (hardened by keratin)
Renews itself ~ every 35 - 45 days
Need to know this slide!
Dust Mites – eat your dead keratinocytes
Epidermis – cell types – Go to FIGURE 1 of notes & fill in cell info (upper right)
Slide 4.10a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Keratinocytes
produce keratin – waterproofing proteinWhy important? To keep you from gaining/losing water
Originate in deeper layers & get pushed to surface – becomes keratin filled & dies
Reminder: Connected to each other by desmosomes & tight junctions
Cell production & keratinization are accelerated in areas of friction
Callus – thickened skin for protection
Keratinocyte Growth
Epidermis – cell types – FIG. 1
Slide 4.10a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Melanocytes• Produce melanin which
accumulates on superficial (between nucleus & sun) side of nucleus
• Why that location? to prevent DNA mutation from the UV radiation
Mutation can change growth instructions & cause cancer
Side Note:
• Freckles and moles = areas where melanin is concentrated in one spot.
• Despite protection of melanin, over time the exposure eventually damages the skin permanently:
• Elastic fibers begin to clump = leathery skin
• Depresses the Immune System
• Skin Cancer
Melanocytes
Label the 5 strata on FIGURE 1 left side
Reflection
• Through research it has been found that darker skinned individuals seldom have skin cancer.
• Why do you think that is?
5 epidermal strata– place info on page 5 right side
Slide 4.10a
From deep to superficial
Stratum basale highly mitotic Approx. 25% melanocytes
Stratum spinosum Slightly mitotic Contains Langerhan’s
macrophages
5 strata of the Epidermis
Slide 4.10a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Stratum granulosum
Also contains Langerhans cell
contains keratin granules
Stratum lucidum
found in thicker epidermis – palms, soles, callus
Completely keratinized (and dead!)
5 strata of the Epidermis
Slide 4.10a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Stratum corneum
Also completely keratinized (& dead)
Tough, waterproofing protection
AGAIN: Why is waterproofing important?
How it all fits together
Dermis – back to FIGURE 2
Slide 4.13a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Left side: Strong, flexible CT - 2 layersRight side - Papillary dermis
Contains areolar CT Dermal papillae – indent into the
epidermis – form fingerprintsWhat else is important about these? Give us grip !
Also contain
nerve receptors,
capillary loops, glands, etc.
Blister: add in margin NEXT TO FIGURE 2
• Dermal – epidermal junction
• Held together by desmosomes
• Blister - separation due to mechanical stress
• What 2 sublayers actually separate? Think about this!!
Dermis
Slide 4.13a
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
FIGURE 2 right side Reticular Dermis
Reticular CT & Dense irregular CT – also contains Blood vessels, Nerve receptors, Glands
cleavage lines – direction of fibers in collagen bundles – used in plastic surgery to reduce scarring
flexure lines – dermis secured to hypodermis
stretch marks – dermal tears
Cleavage lines
Decubitus Ulcers
• Any restrictions of normal blood supply to skin, causes cell death, and if sever and long enough causes ulcers.
• Common in Bedridden Patients.
DERMIS
• Both Collagen & Elastic Fibers are found throughout the dermis.
• *Collagen helps with toughness & hydration.
• *Elastic Fibers help with elasticity when we are young
• As we age the amount of these fibers decrease skin begins to sag and wrinkle
Dermis
Hypodermis – FIGURE 2 left side
Slide 4.10b
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Deep to dermis is the hypodermis - superficial fascia
Anchors skin to underlying organs, shock absorption, insulation
Composed mostly of adipose tissue
Very vascular
Site of subcutaneous injections
5 Tissues
• There have been 5 types of tissues during the previous slides
• You will need to MEMORIZE the location/function/slide of these 5 for this unit test
Skin StructureSkin Structure
Slide 4.13bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 4.4
Skin color
Normal Skin Color Determinants
Slide 4.14Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Determined by a combo of:Types of pigments presentBlood circulation
Stratum corneum thickness
Normal Skin Color Determinants
Slide 4.14Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
MelaninYellow, brown or black pigments
produced in melanocytes found in stratum basale – transferred to keratinocytes
Local accumulations form freckles & pigmented moles
Amount of melanin produced depends upon genetic and exposure to sunlight
Solar elastosis – clumping of elastin fibers = leathery looking skin
Slide 4.14
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Carotene Orange-yellow
pigment from some vegetables
Vitamin A precurser – vitamin A forms retinal which is needed for sight
Accumulates in adipose and stratum corneum cells
Normal Skin Color Determinants
Normal Skin Color Determinants
Slide 4.14Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hemoglobin & blood circulation
Red coloring from oxygenated blood cells in dermis capillaries
Oxygen content determines the extent of red coloring
More obvious in fair skinned individuals
Blood flow
Vasodilation causes increase in flow
Vasoconstriction causes decrease in flow
Skin as a Diagnostic
Slide 4.14Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Skin color is influenced by emotional & disease states: You should know the states that cause these. Cyanosis – bluish color - lack of oxygen Erythema – redness – heat, inflammation,
fever Add this -Pallor – paleness – lack of
blood flow Jaundice – yellowish color – liver damage Bronzing – bronze (tan) – Addison’s
disease Hematomas – black & blue – blood under
skin
Skin Derivatives
Hair Anatomy
Slide 4.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Central medulla
Cortex surrounds medulla
Cuticle on outside of cortex
Single layer of overlapping cells
Split ends – cuticle flakes off – fibers in cortex fray out
Figure 4.7b
Hair anatomy
• Hair shaft – above skin
• Hair root – below skin
Appendages of the Skin
Slide 4.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hair
Shaft – projects from skin
Add in margins: Shape determines hair curliness
Flat = curly
Oval = wavy
Round = straightFigure 4.7c
Hair Follicle
Slide 4.18
Hair - Extends into dermis & hypodermis
Produced by hair bulb- expanded end
Papilla contains capillaries in bulb for hair nourishment (fix in notes!)
Matrix = growth zone – directly surrounds papilla
Figure 4.7c
Associated Hair Structures
Slide 4.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Arrector pilli
Smooth muscle regulated by emotions
Contraction pulls hair upright - Normally at angle
Figure 4.7a
Arrector Pili Muscle
Hair Color
Slide 4.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Caused by proportions of 3 types of melanin
Determined by genetics
Melanin is replaced by air bubbles in gray/white hair – causes different texture Figure 4.7b
Hair Types
Slide 4.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Vellus hair – softer body hair
Terminal hair – coarser hair found in axillary & anogenital regions & other body regions
Lanugo – newborn baby fuzz Figure 4.7a
Hair Growth
Slide 4.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Influenced by (in order):
Nutrition: main influence
hormones
Blood flow
Figure 4.7a
Cycles
Thought Question: know the answers to these questions!!
• Why is the hair on your head longer than the hair in your eyebrows?
• Why does some hair fall out every day?
• Approx 100 hairs per day are lost from your head! That is why your sink is stopped up!
Androgenetic Alopecia
Slide 4.20Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Male pattern baldness Sex linked,
recessive trait Punnett Square!
Figure 4.7a
Causes thinning hair in women
Androgenetic Alopecia
Increased activity in androgen receptors causes hair loss & increases other health risks such as coronary heart disease and prostate cancer in men and polycystic ovary syndrome in women
Terminal hair replaced by vellus hair -progresses posteriorly
Treatment: drugs that inhibit testosterone production (Rogaine, Propecia)
FYI: Polycystic Ovarian Syndrome
More on these topics when we study the Endocrine System
Imbalance: FYI
• Thinning hair can be caused by an abundance of factors.
• Heterozygous traits
• Nutrition
• Medications
• Stress (affects nutrition & hormones)
• Hormones
• Physical factors
Appendages of the Skin
Slide 4.21Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Nails: Just know diagram & these imp. facts – add to diagram: Scale-like modifications of the
epidermis
Heavily keratinized
Stratum basale extends beneath the nail bed to form nail matrix
Which is responsible for growth
Lack of pigment makes them colorless
Nail Structure
Nail Structure
Know all parts labeled on diagram
Why is lunula white?
What happens if matrix is damaged?
Cutaneous Glands
• Are ALL Exocrine Glands they release secretions to the surface using DUCTS. Reside in the Dermis. (Made in the Stratum Basale)
• These fall into 2 groups:
• 1. Sebaceous Glands
• 2. Sweat Glands
Appendages of the SkinAppendages of the Skin
Slide 4.15Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
1. Sebaceous glands found all over skin except palms and soles of feet.
Produce oil called Sebum.
Lubricant for skin
This sebum also kills bacteria
Most with ducts that empty into hair follicles
Glands are activated at puberty
If these glands are blocked causes acne if material oxidizes and dries, get blackheads.
Sweat Glands
Slide 4.16Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Sudoriferous (sweat) glands
Three types
Eccrine glands
Widely distributed in skin: abundant on palms, soles, forehead
Open via duct to pore on skin surface
Sweat composition: mostly water with a slightly acidic 4-6 pH
Function: thermoregulation
Sweat Glands
Slide 4.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
• Apocrine glands (also sudoriferous)
Ducts empty into hair follicles Found mainly in anogenital & axillary
region Begin to function at puberty due to
hormones Organic contents: Fatty acids and
proteins – can have a yellowish color that stains clothes
Odor is from associated bacteria
Sweat Glands
Slide 4.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Ceruminous glands
Modified apocrine gland Found in outer 1/3 of ear canal Produce ear wax to trap “invaders”
Appendages of the Skin
Slide 4.15Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Sebaceous glands (all over except palms and soles of feet)
Produce oil for waterproofing
Lubricant for skin & kills bacteria
Most with ducts that empty into hair follicles
Glands are activated at puberty: stimulated by hormones
Imbalances
• Upper right hand box in notes;
• Acne – active infection of sebaceous glands
• Whitehead - Sebaceous gland duct blocked by sebum
• Blackhead – sebum oxidizes, dries, and darkens
• Seborrhea – “cradle cap” – Over activity of sebaceous glands in infants
Skin Homeostatic ImbalancesSkin Homeostatic Imbalances
Slide 4.23Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Infections Athletes foot
Caused by fungal infection
Boils and carbuncles
Caused by bacterial infection
Cold sores
Caused by virus
Skin Homeostatic ImbalancesSkin Homeostatic Imbalances
Slide 4.24Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Infections and allergies Contact dermatitis
Exposures cause allergic reaction
Impetigo
Caused by bacterial infection
Psoriasis
Cause is unknown
Triggered by trauma, infection, stress
Skin Homeostatic ImbalancesSkin Homeostatic Imbalances
Slide 4.25Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Burns
Tissue damage and cell death caused by heat, electricity, UV radiation, or chemicals
Associated dangers
Dehydration
Electrolyte imbalance
Circulatory shock
Rules of NinesRules of Nines
Slide 4.26Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Way to determine the extent of burns
Body is divided into 11 areas for quick estimation
Each area represents about 9%
Severity of BurnsSeverity of Burns
Slide 4.27Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
First-degree burns Only epidermis is damaged Skin is red and swollen
Second degree burns Epidermis and upper dermis are damaged Skin is red with blisters
Third-degree burns Destroys entire skin layer Burn is gray-white or black
Critical BurnsCritical Burns
Slide 4.28Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Burns are considered critical if:
Over 25% of body has second degree burns
Over 10% of the body has third degree burns
There are third degree burns of the face, hands, or feet
Skin CancerSkin Cancer
Slide 4.29Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Cancer – abnormal cell mass
Two types 1. Benign
Does not spread (encapsulated)
2. Malignant
Metastasized (moves) to other parts of the body
Skin cancer is the most common type of cancer
Skin Cancer TypesSkin Cancer Types
Slide 4.30Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Basal cell carcinoma Least malignant
Most common type
Arises from statum basale
Squamous cell carcinoma Arises from stratum spinosum
Metastasizes to lymph nodes
Early removal allows a good chance of cure
Skin Cancer TypesSkin Cancer Types
Slide 4.31Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Malignant melanoma Most deadly of skin cancers
Cancer of melanocytes
Metastasizes rapidly to lymph and blood vessels
Detection uses ABCD rule
ABCD RuleABCD Rule
Slide 4.32Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
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
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