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33 Cards in this Set
- Front
- Back
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accessory structures of the integumentary system
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hair nails and glands
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Two layers of the skin
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Epidermis and dermis
Hypodermis is associated but not part of the skin. |
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Hypodermis
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composed largely of adipose and areolar tissue and it anchors the skin to its underlying structures, such as muscle.
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Stratum Basale:
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The deepest layer of the skin. These cells rest on the basement membrane and are stem cells capable of dividing. Major cells in this area are keratinocytes, melanocytes, and merkel cells.
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Stratum Spinosum:
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This layer is several cell layers thick and the cells are connected with desmosomes. Cells contain keratin protein fibers and lamellar bodies. Langerhan’s cells are found most often in this layer.
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Stratum Granulosum:
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This is a thin layer of cells which contain keratohyalin granules. This is the last layer of living cells. The cells within the most superficial area of this layer loose their nucleus and other organelles as they degenerate.
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Stratum Lucidum:
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This layer is only found in only in thick skin and is lacking entirely in the thinner skin that covers most of your body. Areas of your body that would have thick skin would be the palm of your hands and the soles of your feet. Cells in this layer are anucleated, keratinized, and dead.
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Stratum Corneum:
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This is the most superficial layer of skin and makes up the majority of the area of the epidermis. Cells in this layer are cornified to protect against abrasion and penetration and are waterproofed by glycolipids present between the cells. Cells are constantly being sloughed off from this layer.
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Dermis has two layers
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1) Papillary
2) Reticular |
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Papillary Layer:
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This is the most superficial layer of the dermis. It is composed of loose areolar connective tissue and is highly vascularized with cutaneous receptors present. The dermal papillae of this region project into the epidermis to form a wavy border. Meissner’s Corpuscles which are light touch sensory receptors are found within this region.
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Reticular Layer:
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This region accounts for the majority of the dermal area. It is composed of dense irregular connective tissue and is highly vascularized. Pacinian receptors that detect deep pressure are found within this layer along with sensory nerve endings. Hair follicles, arrector pili, and glands are also present within this layer.
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Skin color is determined by the presence of which three pigments
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Melanin
Carotene Hemoglobin |
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Melanin
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Only pigment found in the skin, comes from melanocytes among individual its production depends on enzyme tyrosinase
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Melanocytes
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ound in the stratum basale produce melanosomes full of melanin which are phagocytized by the keratinocytes in the upper layers of the epidermis. Since most people have approximately the same number of melanocytes present, it is the particular type of melanin produced that accounts for the variety of skin color among different races of people. Melanocytes are activated to increase their production of melanin when they are exposed to ultraviolet radiation. This is why you tan. This increased melanin protects the DNA from damage.
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Carotene
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ound in the stratum basale produce melanosomes full of melanin which are phagocytized by the keratinocytes in the upper layers of the epidermis. Since most people have approximately the same number of melanocytes present, it is the particular type of melanin produced that accounts for the variety of skin color among different races of people. Melanocytes are activated to increase their production of melanin when they are exposed to ultraviolet radiation. This is why you tan. This increased melanin protects the DNA from damage.
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Hemoglobin
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s the pigment found in red blood cells. This pigment is responsible for the red color of oxygenated blood. This pigment contributes to the "rosiness" of skin. The lighter the color of melanin present, the greater influence hemoglobin has on overall coloration. Additionally, the closer blood vessels are to the skin, the more apparent this pigment is.
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First-degree burns
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These are considered superficial burns. Only the epidermis is damaged.
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Second-degree burns
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The entire epidermis and the upper regions of the dermis are damaged.
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Third-degree burns
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These are considered full-thickness burns. Both the epidermis and the dermis are damaged.
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Two main types of glands
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Sweat and oil
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Sudoriferous (sweat) glands
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Sweat glands are extremely numerous, covering almost the entire body (except nipples and parts of the external genitalia). Sweat glands may be classified as either eccrine or apocrine, depending upon the substance they secrete.
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Eccrine sweat glands
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These are found over most of the body and are the most numerous type of sweat glands. They secrete a type of sweat which is largely composed of water (approximatley 99%) which is filtrated from the blood. In addition to water, minute amounts of salts, metabolic wastes, antibodies, lactic acid and vitamin C make up the other approximately 1% of sweat's composition. These sweat glands may be heat activated or emotionally induced. They largely contribute to the maintainance of body temperature through their activation.
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Apocrine sweat glands
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These sweat glands are found only in the armpit and groin areas of the body. They secrete sweat into hair follicles and their sweat is similar in composition to that of the eccrine sweat glands except for added fatty substances and proteins. This makes this sweat more viscous with a slightly whitish tinge to it.
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Sebaceous (oil) glands
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These glands secrete sebum or oil either into a hair follicle or to the surface of the skin. Sebum helps maintain skin and hair textures by slowing water loss, and making it softer. Additionally, sebum is bactericidal.
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How is hair color determined?
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by the amount and kind of melanin pigment produced within the hair cortex by melanocytes and may change over time. White/gray hair has drastically decreased amounts of melanin or lacks melanin completely.
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Arrector pili muscle
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is a bundle of smooth muscle tissue that is associated with individual hair follicles. When stimulated, contraction of this muscle causes hair to elevate or "stand up" and may dimple the skin forming "goose bumps."
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Two types of hair
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Vellus and terminal
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Vellus hair
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thinner, softer (body hair of children and adult females)
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Terminal hair
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Thicker, coarser hair, may be darker in color than vellus hair. Hair found on the axillary (underarm) and pubic regions of males and females. This hair type is also found on the face, chest, arms, and legs of males.
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Three factors that contribute to hair growth
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Nutrition: Poor nutrition results in poor hair growth.
Dermal Blood Flow: Increased dermal flow enhances hair growth. Hormones: Sex hormones (androgens and testosterone) stimulate terminal hair growth. |
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Nails
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ails are composed of a mass of keratinized cells. Nails contain the same type of hard keratin found in hair. The exposed nail is composed of dead cells, while cell division occurs in the underlying nail bed. Nails appear pink due to the hemoglobin in the capillaries of the underlying dermis. The white, moon-shaped portion of the nail is the lunula which lies over the thick nail matrix. The cuticle is the overgrowth of the stratum corneum layer of the skin which attaches to the proximal nail fold.
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Lanugo coat
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is a layers of delicate hairs that cover a fetus. These appear approximately in the fifth month of development and are shed in approximately the seventh month of development. At this point vellus hairs replace the lanugo coat.
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Vernic Caseosa
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is a white, cheesy looking substance that covers a newborn. This covering is a result of secretions by the fetus's sebaceous glands within the amnion.
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