Integument is the body covering, what does it do and how does it do it? 10/3 What do we call skin? What are the layers of the epidermis? What are the cell types in the epidermis? What critters inhabit your skin? What determines skin color? What are the layers of the dermis? What is the function of the hypodermis? What types of subcutaneous gland do we have?

Practice Quiz 1) ________tissue consists of layers of flat cells that lack keratin. Where is this tissue found? 2) _______ consists of cells that have cilia and an elongated shape with all cells in contact with basement membrane, but an irregular nuclei arrangement. Where is this tissue found?.....__________ 3) ________tissue line all blood vessels. What are these cells called?_____ Name two physiological activities these cells perform. A) B) 4) Name the three primary germ layers and a tissue in the adult derived from each. A) B) C)

Integument is the sum of two parts: epidermis and dermis, with extra support from a third layer (the hypodermis). Weight and area: Thickness variability: Callus: Diseases: Dermatology:

Hypodermis (Adipose CT; Subcutaneous Fat) underneath the Dermis Technically the hypodermis is not part of the skin (integument) Areolar CT under basement membrane, this is especially evident in space FILLED by the dermal papillae The Integument is a mix of many different tissues working together! AN OVERVIEW: Smooth Muscle

Depending on environmental stimuli, you may observe five distinct epidermal layers. NO blood vessels are found in the epidermis! WHERE IS THE BASEMENT MEMBRANE? Stratum Basale: “keRatinocytes”, “melanocytes”, “merkel cells” Stratum Spinosum: desmosomes, dna, keratin, and spines Stratum Granulosum: keratinocyes and vesicle secretion Stratum Lucidum: eleidin and no organelles Stratum Corneum: thick or thin-desquamation/exfoliation How do nutrients reach these layers?

The Epidermis has five layers:

Melanocytes near the stratum basal produce a protein that gives the skin a dark pigment (melanin) that protects the underlying cells from UV radiation.

What determines skin color and how do we see or use color to diagnose disease? Healthy things in skin: Hemoglobin: Red/Blue Blushing(erythema) Melanin/melanocytes Freckles Carotene Fortune Telling: friction ridges, creases and lines Pathological Skin: Smoking and age lines Maybe Moles- Hemangioma- Capillary H.-childhood Cavernous H.-for life Cyanosis- Erythrema (blushing)- Pallor vs. Blushing- Hematoma- Albinism- Jaundice-

What is the dermis composed of? Many tissues can be found here! Superficial Papillary layer (1/5): Basement membrane- Loose areolar tissues- Deeper Reticular layer (4/5): Dense irregular CT contains Collagen (lots of fibroblasts), ground substance, a few adipocytes, nerves, blood vessels, and piloerector muscles Also: Glands and Hair Follicles Hair follicles and goose bumps: Striae in lifters, mothers and weight watchers

The hypodermis (subcutaneous) layer is rich in adipocytes. This tissue layer lies underneath the Integument. Other Names: Subcutaneous or superficial fascia Why are elderly/infants/anorexics often cold to touch? Distribution of adipicytes in hydodermis differs in males and females: SubCutaneous injection rational: Lipophyllic drug administrations: Drug/carcinogen accumulations:

Five kinds of gland: 1)Sebaceous, 2)Apocrine, 3)Merocrine(Eccrine), 4)Mammary and 5)Ceruminous. Glandular secretions often enter “ducts” that permit the fluid to exit onto the surface of the body (simple cuboidal). Larger ducts are often lined with transitional cuboidal tissues in order to protect the underlying tissues.

In what ways do the glands of the skin look different? Merocrine/Apocrine Glands: sweat via filtration from the blood Holocrine (Sebaceous) Glands: oils to surface via cell death/degradation

What five glands are in the integument and what do these glands do for us? Two Types of Sweat Gland: Sweat(Merocrine/Eccrine) vs Scent (Apocrine) Diaphoresis vs. Insensible Loss  heatloss Bromhidrosis and bacteria  scent Myoepithelial cells Where are they densely packed? Why? Mammary Glands= modified sweat glands Sebaceous Glands= secrete sebum (oils+dead cells) into hair follicle, (shiny vs dull hair) Ceruminous Glands: cabbages grew in your childhood ears using cerumen. Acne occurs when the hair follicle gets plugged and secretions accumulate. Bacteria move in and initiate inflammation (“rubor”) in the dermis under the “zit”…be careful when you pop it! How do we limit glandular infections?