Integumentary System: Ms. Halbohm - PowerPoint Presentation

Slide1

Integumentary System:

Ms. Halbohm

AnatomySlide2

Today:

Read Pages 108-111 and define the following terms:

Body membranes

Epithelial membranesCutaneous membranesMucous membranesSerous membranesSerous fluidPeritoneumPleuraPericardium

Synovial membranes

Skin

Integumentary system

Integument

Keratin

Then I have an article on skin for you to read.

We will take our test tomorrow and I will have a video on skin for you to watch on Monday. Slide3

Warm up:

Start by filling in the diagram about what you know, and what you want to know about the integumentary system (skin). Slide4

Today’s objective:

What is the integumentary system and what is it’s function?Slide5

Body Membranes:

1. Body membranes -

cover surfaces, line body cavities, and form protective (and often lubricating) sheets around organs.

2. Fall into two categories: Epithelial membranes – cutaneous, mucous, and serous membranes.Connective tissue membranes – synovial membranes.

We will spend most our time talking about the cutaneous membrane (skin) during this chapter, but we will start with the other membranes first. Slide6

Epithelial Membranes:

Epithelial membranes

include the cutaneous membrane (skin), the mucous membranes, and the serous membranes.

Although these membranes are called epithelial, they also contain an underlying layer of connective tissue, therefore they are actually simple organs. Slide7

Cutaneous Membrane:

3. The Cutaneous membrane is your

skin

. Its superficial epidermis is composed of a keratinizing stratified squamous epithelium.The underlying surface is mostly dense (fibrous) connective tissue.Unlike the other epithelial membranes, your skin is exposed to air, so it is a dry membrane. Slide8

Mucous Membranes:

4. A

mucous membrane (mucosa)

is composed of epithelium resting on a loose connective tissue membrane called a lamina propria. 5. This membrane type lines all body cavities that open to the exterior, such as those of the hollow organs of the respiratory, digestive, urinary, and reproductive tracts. Most mucosae contain either stratified squamous epithelium or simple columnar epithelium.

In all cases, they are “wet” or moist membranes that are continuously bathed in secretions.Slide9

Serous Membranes:

6

. Serous Membranes (serosa):

composed of a layer of simple squamous epithelium resting on a thin layer of areolar connective tissue. 7. Serous membranes line body cavities that are closed to the exterior (except for the dorsal cavity and joint cavities). Serous membranes occur in pairs with the parietal layer lining a specific portion of the wall of the ventral body cavity. This layer folds on itself to form the visceral layer, which covers the outside of the organs in that cavity. Slide10

Serous Membranes:

8.In the body, the serous layers are separated not by air but by a small amount of thin, clear fluid called

serous fluid,

which is secreted by both membranes. The serous fluid allows the organs to slide easily across the cavity walls and one another without friction as they carry out their routine functions. This is important when mobile organs such as the pumping heart and the churning stomach are involved. Slide11

Serous Membranes:

9. The serosa lining the abdominal cavity and covering its organs is the

peritoneum.

10. The serosa lining the lungs is the pleura. 11. The serosa lining the heart is the pericardium. Slide12

Connective Tissue Membranes:

12. Synovial Membranes

are composed of soft areolar connective tissue and contain no epithelial cells at all.

13. These membranes line the fibrous capsules surrounding joints, where they provide a smooth surface and secrete a lubricating fluid. They also line small sacs of connective tissue called bursae and the tubelike tendon sheaths which both cushion organs moving against each other during muscle activity. Slide13

Integumentary system (skin)

14. Your

skin

is essentially like a coat that is waterproof, stretchable, washable, invisibly repairs small cuts, rips and burns, and is guaranteed to last a lifetime with reasonable care. 15. Your skin, sweat and oil glands, hair and nails together are called the integumentary system. Slide14

Next:

Let’s go back to the chart at the beginning of class and describe what we learned today. Slide15

Next:

You have labeling to do that we are going to do as a class. Slide16

Basic Skin Functions:

16. Also called

integument

(“covering”), the skin is much more than an external body covering. It is essential because it keeps water and other precious molecules in the body as well as keeps excess water and bad molecules in the body. Without our skin, we would quickly be taken over by bacteria and would not be able to survive from water and heat loss. Slide17

17. The skin serves many functions, but mainly

protection

, as well as it

insulates and cushions the deeper body organs and protects the entire body from mechanical damage, thermal damage, ultraviolet radiation, and bacteria. Slide18

Basic Skin Functions:

18. The uppermost layer of skin is full of

keratin

and cornified, or hardened, in order to prevent water loss from the body surface. 19. The skins rich capillary system and sweat glands play an important roll in regulating heat loss from the body surface. 20. The skin also acts as a mini

excretory

system due to the loss of urea, salts, and water in sweat.

21. The skin also manufactures several

proteins

important to immunity and synthesizes vitamin D.

22. The cutaneous

sensory

receptors, which are actually part of the nervous system, are located in skin as well which include touch, pressure, temperature, and pain receptors, provide us with a great deal of information about our external environment. Slide19

Structure of the skin:

23. The skin is composed of two kinds of tissue:

1. The outer

epidermis is made of stratified squamous epithelium that is capable of keratinizing, or becoming hard and tough. 2. The underlying dermis is mostly made of dense connective tissue. 24. The epidermis and dermis are firmly connected but an abrasion such as a burn may cause them to separate allowing interstitial fluid to accumulate in the cavity between the layers, which results in a blister

. Slide20

Structure of the Skin:

25. Deep to the dermis is the

subcutaneous tissue,

or hypodermis, which is mostly adipose tissue. It is not considered part of the skin, but it does anchor the skin to the underlying organs. 26. Subcutaneous tissues acts as a shock absorber and insulates the deeper tissues from extreme temperature changes occurring outside the body. It is also responsible for the “curves” that many women have. Slide21

Epidermis:

27. The epidermis is made up of five layers called

strata.

From the inside out, they are stratum basale, spinsosum, granulosum, lucidum, and corneum.

28. Like all epithelial tissues, the epidermis is

avascular

, meaning it has no blood supply of its own.

Therefore, this is why a man can shave everyday and not bleed even though he is shaving off several cells each day.

29. Most cells of the epidermis are

keratinocytes,

which produce keratin, the fibrous protein that makes the epidermis a tough, protective layer. Slide22

Epidermis:

30. The deepest cell layer of the epidermis is the

stratum

basale, which lies closest to the dermis and contains epidermal cells that receive the most adequate nourishment via diffusion of nutrients from the dermis. These cells are constantly undergoing cell division, and millions of new cells are produced daily. Slide23

Projects:

You are going to create a model of skin structure using poster board/construction paper.

Instead of just drawing it, you are going to cut out shapes of the actual structures such as the hair follicles, epidermis, etc. and then attach them to the poster board. Use the picture on page 113 as a guide.

We will later label the structures once we have finished our discussion on skin structure. You make work together or alone, but be thorough and do a good job!Slide24

Today:

We are going to take some notes then you may work on your projects.

You projects will be due next Thursday and will be combined with a chapter test for your semester grade. Slide25

Epidermis:

The daughter

cells of the stratum

basale are pushed upward, away from the source of nutrition, to become part of the epidermal layers closer to the skin surface. 31. The daughter cells move away from the dermis and become part of the more superficial layers, the stratum spinosum, and then the stratum granulosum. 32. Then, they become flatter, increasingly full of keratin, and finally die, forming the

stratum

lucidum

. Slide26

Epidermis:

33. The

stratum

lucidum is not found in all skin regions, it occurs only where the skin is hairless and extra thick, such as the palms of your hands and the soles of your feet. 34. The outermost layer the stratum corneum is 20-30 cell layers thick and accounts for about ¾ of the epidermal thickness.

The

shinglelike

dead cell remnants, completely filled with keratin, are often referred to as

cornified

cells.

So, the saying “Beauty is only skin deep”, is especially interesting considering everything we see with out eyes is essentially dead cells. Slide27

Epidermis:

35. The

strength

of keratin allows it to be a strong protective overcoat for our bodies and it protects deeper cells from air and water loss as well as biological and physical attacks on the body. 36. The stratum corneum rubs and flakes off slowly and steadily and is replaced by cells produced by the division of the deeper stratum basale cells.

Therefore, we have a new epidermis every 25-45 days.

37.

Melanin

is a pigment that ranges from yellow to brown, to black, and is produced by cells called melanocytes and is found in the stratum

basale

.

When the skin is exposed to sunlight, it stimulates the melanocytes to produce more melanin, and tanning occurs. Slide28

Epidermis:

38. The

stratum

basale cells eat the pigment that is produced and it accumulates inside them. 39. The melanin then forms a protective pigment umbrella over the superficial “sunny” side of the nuclei that shields their genetic material (DNA) from the damaging effects of ultraviolet radiation. 40. Freckles and

moles

are found where melanin is concentrated in one spot. Slide29

Homeostatic (body stability) Imbalance:

Despite melanin’s protective effects, excessive sun exposure eventually damages the skin.

It causes the elastic fibers to clump, leading to leathery skin. It also depresses the immune system.

Overexposure to the sun can also alter the DNA of skin cells and in this way lead to skin cancer. Slide30

Dermis:

41. The

dermis

is a strong stretchy envelope that helps to hold the body together.Leather is the treated dermis of other animals. The dermis consists of two layers: The papillary and reticular areas. Like the epidermis, the dermis varies in thickness, with the thickest parts being the palms of the hands and the soles of the feet, and the thinnest parts being the eyelids. Slide31

Dermis:

42. The

papillary layer

is the upper dermal region, it is uneven and has fingerlike projections from its superior surface, called dermal papillae, which indent the epidermis above. 43. Many of the dermal papillae contain capillary loops, which send nutrients to the epidermis. 44. Others hold pain receptors (free nerve endings) and touch the receptors called Meissner’s corpuscles.

On the palms of the hands and soles of the feet, the papillae are arranged in definite patterns that form looped and whorled ridges on the epidermal surface that increase friction and enhance the gripping ability of the hands and feet. Slide32

Dermis:

Papillary patterns are genetically determined.

45. The ridges of fingertips are well provided with sweat pores and leave unique, identifying films of sweat called

fingerprints on almost anything they touch. 46. The reticular layer is the deepest skin layer. 47. It contains blood vessels, sweat and oil glands, and deep pressure receptors called pacinian corpuscles. Slide33

Dermis:

Both elastic and collagen fibers are found in the dermis.

48.

Collagen fibers are responsible for the toughness of the dermis; they also attract and bind water and thus help to keep the skin hydrated. 49. Elastic fibers give the skin its elasticity when we are young. As we age, the number of collagen and elastic fibers decreases, and the subcutaneous tissue loses fat.As a result, the skin loses its elasticity and begins to sag and wrinkle. Slide34

Dermis:

The dermis has an abundant supply of blood vessels that play a roll in maintaining body temperature homeostasis.

50. When your body temperature is

high, the capillaries of the dermis become enlarged, or swollen, with heated blood, and the skin becomes reddened and warm. This allows body heat to radiate from the skin surface. 51. If the environment is cool, then body heat must be conserved, and blood bypasses the dermis capillaries temporarily, allowing internal body temperature to stay high. Slide35

Homeostatic Imbalance:

Any restriction of blood supply to the skin results in cell death and, if severe or prolonged enough, skin ulcers.

Bedsores occur in bedridden patients who are not turned regularly or who are dragged or pulled across the bed repeatedly.

The weight of the body puts pressure on the skin, especially over bony projections (hips, elbows, etc.) Because this restricts the blood supply, the skin becomes pale or blanched at pressure points. At first, the skin reddens when pressure is released, but if the situation is not corrected, the cells begin to die, and typically small cracks or breaks in the skin appear at compressed sites. Permanent damage to the superficial blood vessels and tissue eventually results in degeneration and ulceration of the skin. Slide36

Skin Color:

52. Three pigments contribute to skin color:

1) The amount and kind (yellow, reddish brown, or black) of

melanin in the epidermis. 2) The amount of carotene deposited in the stratum corneum and subcutaneous tissue. Carotene is an orange-yellow pigment found in abundant amounts in carrots and other

organge

, deep yellow, or leafy green vegetables.

The skin tends to take on a yellowish-orange color when large amounts of carotene-rich foods are eaten.

3) The amount of oxygen-rich

hemoglobin

(pigment in red blood cells) in the dermal blood vessels. Slide37

Skin Color:

People who produce a lot of melanin have brown-toned skin.

In light-skinned (Caucasian) people, who have less melanin, the red color of oxygen-rich hemoglobin in the dermal blood supply flushes through the transparent cell layers above and gives the skin a rosy glow. Slide38

Homeostatic imbalance:

54. When hemoglobin is poorly oxygenated, both the blood and the skin of Caucasians appear blue, a condition called

cyanosis

.Cyanosis is common during heart failure and severe breathing disorders. In dark-skinned people, the skin does not appear cyanotic in the same situations because of the masking effects of melanin, but cyanosis appears in their mucous membranes and nail beds. Slide39

Influences on Skin Color:

55. Redness, or erythema:

M

ay indicate embarrassment (blushing), fever, hypertension, inflammation, or allergy.56. Pallor or blanching: Under certain types of emotional stress (fear, anger, etc.), some people become pale. Pale skin may also indicate anemia, low blood pressure, or impaired blood flow into the area. Slide40

Influences on Skin color:

57. Jaundice (yellow-cast)

– An abnormally yellow skin tone usually indicates a liver disorder in which excess bile pigments are absorbed into the blood, circulated throughout the body, and deposited in body tissues.

58. Bruises (black-and-blue marks) – reveal sites where blood has escaped from the circulated and has clotted in the tissue spaces. Such clotted blood masses are called hematomas. An unsual tendency to bruising may signify a deficiency of vitamin C in the diet or hemophilia (bleeder’s disease). Slide41
Slide42

Appendages of the skin:

59. The

skin appendages

include the cutaneous glands, hair and hair follicles, and nails. Each of these appendages come from the epidermis and play an important role in maintaining homeostasis. Slide43

Cutaneous Glands:

60. The cutaneous glands are all

exocrine glands

that release their secretions to the skin surface via ducts. 61. They fall into two groups:1) Sebaceous glands2) Sweat glandsSlide44

Sebaceous (oil) glands:

62.

The Sebaceous glands

, or oil glands, are found all over the skin, except on the palms of the hands and the soles of the feet. Their ducts usually empty into a hair follicle, but some open directly onto the skin surface. 63. The product of sebaceous glands is sebum (seb = grease), is a mixture of oily substances and fragmented cells. 64. Sebum is a

lubricant

that keeps the skin soft and moist and prevents hair from becoming brittle.

Sebum also contains chemicals that kill bacteria, therefore it is important for preventing the bacteria on the skin surface Slide45

Homeostatic imbalance:

If sebaceous gland’s ducts become blocked by sebum, a whitehead appears on the skin surface.

If the accumulated material oxidizes and dries, it darkens, forming a blackhead.

Acne is an active infection of the sebaceous glands accompanied by pimples on the skin. It can be mild or severe, leading to permanent scarring. Slide46

Sweat Glands:

65.

Sweat glands

(sudoriferous glands) are widely distributed on the skin, each person containing about 2.5 million. 66. There are two types of sweat glands: 1) Eccrine2) ApocrineSlide47

Sweat Glands:

67.

Eccrine

glands: are more numerous and are found all over the body. 68. They produce sweat, a clear secretion that is primarily water plus some salts (sodium chloride), vitamin C, traces of metabolic wastes (ammonia, urea, uric acid), and lactic acid (a chemical that accumulates during vigorous muscle activity). Sweat is acidic (pH from 4 to 6), a characteristic that inhibits the growth of bacteria, which are always on the skin surface. Typically sweat reaches the skin surface via a duct that opens externally as a funnel-shaped pore. Slide48

Sweat Glands:

69. The

eccrine

sweat glands are an important and a highly efficient part of the body’s heat-regulating equipment.70. They are supplied with nerve endings that cause them to secrete sweat when the external temperature or body temperature is high. When sweat evaporates off the skin surface, it carries large amounts of body heat with it. On a hot day, it is possible to lose up to 7 liters of body water by sweating. Slide49

Apocrine glands:

71.

Apocrine glands

are located in the axillary and genital areas of the body and are larger than eccrine glands, and their ducts empty into hair follicles. 72. Their secretions contain fatty acids and proteins, as well as all the substances present in the eccrine secretion, therefore they take on a milky or yellowish color and when combined with the bacteria on the skin can take on that unpleasant odor that we know well known as body odor.

Apocrine glands begin to function during puberty under the influence of androgens (male sex hormones) in both males and females. Their precise function is not known yet. Slide50

Hair and Hair Follicles:

73. There are millions of

hairs

scattered all over the body and they serve only a few purposes such as: guarding the head against bumps, shielding the eyes (eyelashes), and helping to keep particles out of the respiratory tract. Other than that, our bodies have lost its usefulness. Hair use to serve as insulation to early humans in cold weather, but now we have developed other methods of keeping warm. Slide51

Hair and Hair follicles:

74. Hair is produced by a

hair follicle

and is a flexible epithelial structure. 75. The part of the hair enclosed in the structure is called the root. 76. The part projecting from the surface of the scalp or skin is called the shaft. 77. The hair is formed by the division of the well-nourished stratum basale epithelial cells in the matrix

(growth zone) of the hair bulb at the inferior end of the follicle. Slide52

Hair:

Each hair consists of a central core called the

medulla

surrounded by a bulky cortex layer. The cortex is, in turn, enclosed by an outermost cuticle formed by a single layer of cells that overlap one another like singles on a roof. The cuticle is the most heavily keratinized region; it provides strength and helps keep the inner hair layer tightly compacted. Because it is open to the outside, the cuticle tends to wear away at the tip of the shaft, allowing the keratin fibrils in the inner regions to frizz out, we call this “split ends”

Hair also contains melanin much like your skin and your hair color will depend on the quantity and type of melanin your hair contains. Slide53

Hair:

Hair comes in a variety of shapes and sizes.

When the hair shaft is oval, hair is smooth and silky, and the person has wavy hair.

When the shaft is flat, the hair is curly. If it is perfectly round, the hair is straight and tends to be coarse. You are born with all the hair follicles you will ever have and hair is one of the fastest growing tissues in the body and is stimulated by hormones. Slide54

Hair Follicles:

78. Hair follicles are structures that are made up of

two layers.

1) The inner epidermal sheath is composed of epithelial tissue and forms the hair. 2) The outer dermal sheath is actually dermal connective tissue and supplies blood vessels to the epidermal region. Slide55

Goose Bumps:

79. Small bands of smooth muscle known as

arrector

pilli connect each side of the hair follicle to the dermal tissue. When these muscles contract, like when you are cold or frightened, the hair is pulled upright, dimpling the skin surface with “goose bumps”. This action helps keep animals warm in winter by insulating air to the fur. Slide56
Slide57

Nails:

80. A

nail

is a scalelike modification of the epidermis that corresponds to the hoof or claw of other animals. Each nail has a free edge, a body, and a root. The borders of the nail are overlapped by skin folds, called nail folds

. In the nail we call the thick fold the

cuticle.

The stratum

basale

extends beneath the nail as the

nail bed

, with its thickened proximal area, called the

nail matrix

, which is responsible for nail growth. Slide58

Infections and Allergies:

Athlete’s foot:

An itchy, red, peeling condition of the skin between the toes, resulting from fungus infection. Slide59

Infections and Allergies:

Boils and Carbuncles:

Inflammation of hair follicles and sebaceous glands, common on the dorsal neck. Carbuncles are composite boils typically caused by bacterial infection. Slide60

Infections and Allergies:

Cold Sores:

small fluid-filled blisters that itch and sting, caused by a herpes simplex infection.

The virus hangs out in a cutaneous nerve, where it remains dormant until activated by emotional upset, fever, or UV radiation. Usually occur around the lips. Slide61

Infections and Allergies:

Contact dermatitis:

Itching, redness, and swelling of the skin, progressing to blistering. Caused by exposure of the skin to chemicals (like poison ivy) that provoke allergic responses to sensitive individuals. Slide62

Infections and Allergies:

Impetigo:

Pink, water-filled, raised lesions (usually around the mouth and nose) that develop a yellow crust and eventually rupture. Caused by a highly-contagious staph infection. Slide63

Infections and Allergies:

Psoriasis:

A chronic condition, characterized by overproduction of skin cells that results in reddened epidermal lesions covered with dry, silvery scales.

When severe, it may be disfiguring. It is believed to be an autoimmune disorder in which the immune system attacks a person’s own tissues. Attacks often triggered by trauma, infection, hormonal changes, and stress. Slide64

Burns:

A

burn

is tissue damage and cell death caused by intense heat, electricity, UV radiation, or certain chemicals (such as acids). The volume of fluid lost by a burn can be estimated indirectly by determining how much of the body surface is burned using the rule of nines. This method divides the body into 11 areas, each accounting for 9% of the total body surface as well as an additional area which makes up 1% of the total body surface. Slide65

Burns:

First degree burns:

only the epidermis is damaged. The area becomes red and swollen.

Not usually serious and generally heal within two to three days. Slide66

Burns:

Second degree burns:

involve injury to the epidermis and the upper region of the dermis. The skin is red and painful and blisters appear.

Usually, no scarring takes place if the burns are taken care of properly. First and second degree burns are classified as partial-thickness burns. Slide67

Burns:

Third degree burns:

destroy the entire thickness of the skin, so they are called

full-thickness burns. Appears blanched (grey-white) or blackened, and since nerve endings are destroyed, the burn area is not painful. Regeneration is not possible and skin grafting is necessary to cover the burned area. Slide68

Skin cancer:

Basal Cell carcinoma:

Is the least malignant and most common skin cancer. Cells of the stratum

basale, are altered so they cannot form keratin, and the boundary between the epidermis and dermis is no longer present. They proliferate, invading the dermis and subcutaneous tissue. The cancer lessions occur most often on sun-exposed areas of the face and appear shiny, dome-shaped nodules that later develop a central ulcer with a “pearly” beaded edge. Full cure in 99% of cases is possible by removing the lesions. Slide69

Skin Cancer:

Squamous cell carcinoma:

Arises from the cells of the stratum

spinsonum. The lesions appear as a scaly, redden papule (small, rounded, elevated) that gradually forms a shallow ulcer with a firm, raised border. Appears most often on the scalp, ears, dorsum of the hand, and lower lip. It grows rapidly and moves to nearby lymph nodes if not removed. If it is caught early and removed surgically, chances of a cure are good. Slide70

Skin Cancer:

Malignant Melanoma

: a cancer of melanocytes. It accounts for only about 5% of skin cancers, but cases are increasing in number rapidly and are often deadly.

It can begin wherever there is pigment. It arises from accumulated DNA damage in a skin cell and usually appears as a spreading brown to black patch that moves and grows rapidly to surrounding lymph and blood vessels. The change for survival is about 50% and early detection helps. Slide71

ABCD Rule:

The American Cancer Society suggests you check yourself periodically for new moles or pigmented spots if you spend a great deal of time in the sun and to also follow the

ABCD Rule:

(A) Asymmetry: the two sides of the pigmented spot or mole do not match. (B) Border Irregularity: the borders of the lesion are not smooth but exhibit indentations. (C) Color: the pigmented spot contains areas of different colors (blacks, browns, tans, and sometimes blues and reds).

(D) Diameter:

the spot is larger than 6 millimeters in diameter (the size of a pencil eraser) Slide72

Developmental Aspects:

During the fifth and sixth months of fetal development, the soon-to-be infant is covered in a downy type of hair called

lanugo,

but this cloak is usually shed by birth. When a baby is born, their skin is covered with vernex caseosa, a white, cheesy-looking substance, produced by the sebaceous glands, and protects the baby’s skin while it is floating in its water-filled sac inside the mother.

The newborn’s skin is very thin, and blood vessels can be easily seen through it.

Our skin starts to get oily again during adolescence before it reaches its peak in our twenties.

We then start to see visible changes in our skin appearance due to wind, sun, chemicals, and pollution getting in our pores. Slide73

Developmental aspects:

As we age, our skin starts to lose its elasticity and the amount of subcutaneous tissue we have, which leads to elderly people feeling more cold easily.

The loss of elasticity is speed up by both smoking and exposure to the sun. Therefore, the best way to prevent that process from beginning is to not smoke and protect your skin from the sun.

Your hair follicles also start to degenerate as you age which leads to hair loss. Gray hair is caused by a gene that controls the amount of melanin that is deposited in the hair. The best way to prevent both hair loss and graying is a nutritious diet and a healthy lifestyle. Slide74

Next:

You can work on your projects.

You can now start labeling as well because we have learned all of the structures that will be in your models. Slide75