histology

Question Answer
Functions of Skin 1. Protection against physical abrasions, chemical irritants, pathogens, UV radiation, and dessication2. Thermoregulation – regulates body temperature3. Reception of pressure and touch sensations4. Production of vitamin D5. Excretion
The skin appendages sweat glands, hair follicles, sebaceous glands, and nails
The skin and its appendages are called integument
Components of the skin the epidermis and dermis
what layer is the Epidermis The epidermis is the superficial layer of the skin
type of epithelium found in the epidermis Stratified squamous keratinized epithelium
The epidermis is composed mainly of / Epidermis Cell types keratinocytes and three other types of cells: melanocytes, Langerhans cells, and Merkel cells
define Keratinocytes Keratinizing epidermal cells, major cell type in the epidermis
define Melanocytes Melanin pigment-producing cells
define Langerhans cells Macrophages, antigen-presenting cells
define Merkel cells : tactile epithelial cells; Touch receptors
define Dermis The dermis is the layer of the skin underlying the epidermis.
the dermis is composed of two layers of connective tissue
two layers of connective tissue contain 1. Blood vessels, 2.nerves, 3. Sensory receptors and 4. sweat and sebaceous Glands
define the Hypodermis a layer of loose connective and adipose tissues that forms the superficial fascial layer
Classification of Skin—Based on the Thickness of the Epidermis THIN SKIN and THICK SKIN
THIN SKIN function 1. covers entire body except palms and soles;2. Possesses hair with sebaceous glands3. Sweat glands are present.
THICK SKIN function 1. Located on palms of the hands and soles of the feet2. Hairless and, thus, possesses no sebaceous glands
Layers of the epidermis 1. Stratum granulosum (granular layer)2. Stratum basale (basal layer)3. Stratum lucidum4. Stratum corneum5. Stratum spinosum (spinous layer)
Stratum granulosum (granular layer) contain 3-5 layers of flattened polygonal cells with keratohyalin granules. Present only in thick skin
Stratum basale (basal layer) Deepest layer of epidermis; contains a single layer of cuboidal to columnar shaped cells that rest on the basement membrane
Stratum lucidum A clear layer of non-nucleated, flattened cells that is only visible as a distinct/separate layer in thick skin
Stratum corneum The outer layer of epidermis; containing flattened dead squamous cell, filled with keratin filaments with no nucleus.
Stratum spinosum (spinous layer) contains several layers of keratinocytes, called prickle cells because they appear spiny; the cells are attached to one another by desmosomes.
dermis contains two sublayers Papillary layer & Reticular layer
Papillary layer outer layer of the dermis, consisting of loose connective tissue. It forms the major part of the dermis papillae
Reticular layer deepest layer of dermis; consisting of thick dense irregular connective tissue
list the SKIN APPENDAGES/ STRUCTURES ASSOCIATED WITH THE SKIN Hair, Arrector pili, Sebaceous glands, Sweat glands,Nails
Hair Invaginations of the epidermis consisting of a bulb; for sensation, heat loss
Arrector pili muscles that pull hair straight (goose bumps) and attaches hair follicle to the Papillary layer
Sebaceous glands produce and secrete sebum onto hair follicle
Sweat glands secrete sweat
Nails severe as protection

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