Integumentary Flashcards

Question

Describe accessory structures of hair

Answer 1

**arrector pili** - smooth muscle, causes hairs to stand up. **sebaceous glands** - an exocrine gland which secrete oily substance (sebum) via holocrine secretion. Lubricates the hair and helps control bacteria

Answer 2

**Anagen Phase (Growth Phase)** Duration: Lasts from 2 to 6 years. - a layer of dividing basal cells in the hair bulb divide rapidly, pushing the hair shaft up and out. - Dermal Papilla: Provides nutrients and signals for hair growth through its blood supply. Inner and Outer Root Sheath, support and protect the growing hair. **Catagen Phase (Transition Phase)** Duration: Lasts about 2 to 3 weeks. Activity: Hair growth stops, and the hair follicle shrinks and detaches from the dermal papilla. Club hair forms **Telogen Phase (Resting Phase)** Duration: Lasts about 2 to 4 months. The hair follicle is dormant, and no active growth occurs. The hair remains in the follicle as a club hair. **Exogen Phase (Shedding Phase):** Activity: The old hair (club hair) is shed from the follicle, can be triggered by the growth of a new hair in the *active cycles through everyone*

Answer 3

- It is the region where actively dividing cells proliferate to form the hair shaft and the inner root sheath. The cells in the hair matrix undergo rapid mitosis, producing the cells that will become the hair shaft and the inner root sheath as they move upward and become keratinized (filled with keratin). - The hair matrix is located at the base of the hair follicle, just above the dermal papilla, within the hair bulb.

Answer 4

**Medulla** Location: The innermost layer of the hair shaft. Structure: It consists of loosely packed, soft keratinized cells. Not all hair types have a medulla; it is more commonly found in thicker hairs. **Cortex** Location: Surrounds the medulla and makes up the majority of the hair shaft. Structure: The cortex contains tightly packed, elongated cells filled with hard keratin. It provides strength, elasticity, and determines the hair's color due to the presence of melanin granules. **Cuticle** Location: The outermost layer of the hair shaft. Structure: Composed of a single layer of flat, overlapping cells arranged like shingles on a roof. These cells contain hard keratin and provide a protective barrier for the inner layers of the hair shaft.

Answer 5

- holocrine glands - secrete **sebum**. An oily secretion which contains oils - lubricates and protects the epidermis and hair, inhibits bacterial growth.

Answer 6

**insensible perspiration** -interstitial fluid lost by evaporation through the stratum corneum. We loose between 0.5-0.8 qt per day **sensible perspiration** - water excreted by sweat glands. - We can see / feel this water loss.

Answer 7

**apocrine** - located in armpits, nipples, groin, beard - inactive until puberty - secrete into hair follicles - a sticky, cloudy secretion which break down and cause odors - respond to nervous or hormonal signals. **eccrine sweat glands** - widely distributed on body surface, especially on palms and soles - discharge directly to skin surface - release water, salts and organic compounds - cool skin, flush microorganisms and harmful chemicals *BOTH utilize merocrine secretion*

Answer 8

- modified apocrine glands, produce milk. *apocrine secretion*

Answer 9

- modified apocrine glands in the external ear, produce cerumen (earwax) to protect the eardrum, waterproofs canal, and kills bacteria *apocrine secretion*

Answer 10

**basal cell carcinoma** - 78% of skin cancers - basal cells in stratum basale - rarely metastasize. - often appears as a pearly or waxy bump, a flat, flesh-colored or brown scar-like lesion, or a sore that bleeds, scabs, and returns. - BCC typically develops on areas of the skin that are frequently exposed to the sun, such as the face, neck, and hands. **squamous cell carcinoma** - 20% of skin cancers - Originates from the squamous cells in the stratum spinosum of the epidermis - variable tendency to metastasize - CC often appears as a firm, red nodule, or a flat lesion with a scaly, crusted surface. It can also present as a sore that doesn't heal or a wart-like growth. - Chronic sun exposure, fair skin, a history of sunburns, older age, immunosuppression, and exposure to carcinogenic substances (like tobacco or certain chemicals).

Answer 11

**ABCDE RULE** A: asymmetry B: border irregularity C: color; contains several colors / uneven coloration D: diameter; larger than 6mm E: evolution; changes in A-D

Answer 12

- 2% of all skin cancers - melanocytes - metastasize rapidly, high mortality rate, resistant to chemotherapy

Answer 13

**first-degree** - partial thickness burn, involves only the epidermis - mild pain and erythema (redness) - no blisters - skin functions remain intact **second degree burn** - destroys the epidermis and part of the dermis - some skin functions are lost - redness blister formation, edema, pain - hair follicles, sebaceous glands, and sweat glands usually not injured **third degree burn** - full thickness burn, destroys epidermis, dermis, and hypodermis - most skin functions lost, - edema, burned region is numb, sensory nerve endings destroyed - regeneration occurs slowly, often skin grafts are needed.

Answer 14

- large loss of water, plasma, and plasma proteins, can cause shock - bacterial infection - reduced circulation of blood - decreased production of urine - immune response

Answer 15

1. shock from rapid fluid loss 2. infection 3. toxic effects of eschar (burned / dead tissue)

Answer 16

Permanent graft options **autograft** skin taken from another location on the body. Can be a split graft where only epidermis, and part of the dermis is taken. **isograft** skin from identical twin Temporary graft - will eventually be rejected **homograft** from unrelated person **heterograft** graft from another species **amnion** the innermost layer of the placenta, which can be used as a biological dressing for wounds. **artificial** skin from silicone and collagen

Answer 17

The basement membrane is a specialized extracellular matrix found at the interface between epithelial cells and the underlying connective tissue. It anchors the epithelium to dermis, acts as a selective filter, and influences cell behavior. The basement membrane is composed of the basal lamina and the reticular lamina. The basal lamina can be further subdivided into the lamina lúcida and lamina densa. **basal lamina** Lamina lúcida has laminin, lamina densa collagen IV. Secreted by epithelial cells. **Reticular Lamina** - A layer of the basement membrane located beneath the lamina densa, blending with the underlying connective tissue. - Secreted by connective tissue cells (fibroblasts), composed of type III collagen and extracellular matrix proteins.

Answer 18

found in the deepest layer of the epidermis, the stratum basale. These cells are stem cells, are constantly undergoing mitosis, and are responsible for epithelial regeneration *mesenchymal stem sells -> can become: osteoblasts, chondroblasts, adipocytes, myocytes, fibroblasts*

Answer 19

are the most abundant cell in **epidermis**. They are born from basal cells in the stratum basal and move to the stratum corneum. As they move up the layers they undergo keratinization in which they flatten, become full of keratin, and eventually die forming a protective layer

Answer 20

The boundary between the epidermis and dermis is “wavy”, like corrugated cardboard. This structure provides structural integrity preventing slippage between the epidermal and dermal layers. The epidermal ridge are the downward waves of the epidermis and the dermal papillary are the upward waves of the dermis.

Answer 21

Amount of melanin produced. We have roughly the same number of melanocytes but these cells produce different amounts of melanin. The ratio of eumelanin to pheomelanin produced.

Answer 22

Lamellar granules are formed within keratinocytes in the deeper layers of the epidermis (spinosum and granulosum). As keratinocytes migrate upwards to the stratum granulosum, the granules move to the cell surface and release their contents through exocytosis into the intercellular space resulting in the formation of an impermeable, lipid-containing membrane that serves as a water barrier and is required for correct skin barrier function. The granules themselves contain lipids (cholesterol / free fatty acids), enzymes and other proteins

Answer 23

1. severed vessels bleed into cut. mast cells release histamine, increasing blood flow and making capillaries more permeable. 2. blood plasma seeps into the wound carrying antibodies and clotting proteins. 3. blood clot forms knitting the edges of the cut together inhibiting the spread of pathogens. (fibrin / platelets / blood cells) 4. a scab forms (composed of fibrin, platelets / blood cells) 5. macrophages phagocytize bacteria/dead cells. 6. New capillaries sprout from nearby vessels 7. Deeper portions of a clot become infiltrated by capillaries and fibroblasts. Macrophages remove the blood clot. Fibroblasts deposit new collagen (type III then type I), creating granulation tissue. Begins 3-4 days after injury and lasts of to 2 weeks. 8. epithelial cells around the wound multiple and migrate beneath scab. covering the wound surface, providing protectieve barrier, protecing underlying barrier. 9. underlying connective tissue undergoes fibrosis creating scar tissue may or may not show through epithelium. 10. remodeling maturation phase begins several weeks after injury

Integumentary Flashcards

(47 cards)