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

Body Bugs

NOVA | Bugs That Live on You

http://www.pbs.org/wgbh/nova/nature/bugs-that-live-on-you.html

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


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)


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)


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


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


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


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


Figure 4.4

Epidermis – FIGURE 2 - fill in text box on left side of diagram

Slide 4.10a


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


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


• 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


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


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


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


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


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


Slide 4.13bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 4.4

Skin color

Normal Skin Color Determinants


Determined by a combo of:Types of pigments presentBlood circulation

Stratum corneum thickness



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


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




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


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


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


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


Arrector pilli

Smooth muscle regulated by emotions

Contraction pulls hair upright - Normally at angle

Figure 4.7a

Arrector Pili Muscle

Hair Color


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


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


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


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



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


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


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


• 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


Ceruminous glands

Modified apocrine gland Found in outer 1/3 of ear canal Produce ear wax to trap “invaders”



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


Infections Athletes foot

Caused by fungal infection

Boils and carbuncles

Caused by bacterial infection

Cold sores

Caused by virus



Infections and allergies Contact dermatitis

Exposures cause allergic reaction

Impetigo

Caused by bacterial infection

Psoriasis

Cause is unknown

Triggered by trauma, infection, stress



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


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


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


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


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


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


Malignant melanoma Most deadly of skin cancers

Cancer of melanocytes

Metastasizes rapidly to lymph and blood vessels

Detection uses ABCD rule

ABCD RuleABCD 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

Documents

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