BSCI 201 Review Sheet for Exam 2 A The Integumentary system 1 Name and describe all the strata in the epidermis of a thin layer and a thick layer a from deep to superficial i Stratum basale single layer of cuboidal cells called keratinocytes Always undergoing mitosis mitotically active Contains melanocytes which produces melanin and it protects the skin from UV radiation ii Stratum spinosum several layers of cells joined by desmosomes Cells appear spiny because of the intermediate filaments called tonofilaments and they can withstand pulling forces without the cells separating iii Stratum granulosum 3 5 layers of flattened cells filled with granules 2 types keratohyaline granules and lamellated granules iv Stratum lucidum found only in thick skin 3 5 layers of dead cells appears translucent under a light microscope v Stratum corneum 20 30 layers of dead flattened squamous like cells The dead cells are filled with keratin which makes it abrasive resistant The cells are also coated with gylcolipids making the skin waterproof 2 Describe the following tonofilaments Langerhan s cells lamellated granules keratohyaline granules a Tonofilaments supports and connects the cells to prevent separation letting in pathogens Found in stratum spinosum b Langerhan s cells epidermal dendrite cells act as macrophages in epidermic to engulf or destroy pathogens and to activate specific immune responses if the pathogen gains access into the body Mostly found in stratum spinosum c Lamellated granules d Keratohyaline granules keratinization of the skin which makes the skin water proof Found in the stratum granulosum 3 Name and describe the two layers in the dermis a Superficial papillary layer Highly vasculared areolar connective tissue Surface of the papillary layers is thrown into involutions called dermal papillae Dermal papillae contains 3 structures blood vessels free nerve ending pain receptors and meissner s corpuscles touch receptors b Deep reticular layer stratum reticulerosum dense irregular connective tissue and dense collagen fibers It strengthens the skin structural and elastically 4 Describe the following Meissner s corpuscles Pacinian corpuscles Merkel discs a Meissner s corpuscles light touch receptors in papillary layer of the dermis b Pacinian corpuscles deep pressure receptor in reticular layer of the dermis c Merkel discs light touch receptors in epidermal dermal junctions This is the combination of free nerve endings and merkel cells Merkel cells alone cannot transmit impulses so they are not nervous structures 5 Name and discuss the function of the accessory skin structures What is acid mantle a Sweat glands i Ecrrine mesocrine sweat glands simple coiled tubular multicellular exocrine gland It secretes sweat via the merocrine mod of secretion Sweat prevents the growth of microorganism on the surface of the skin Located in palms soles and forehead ii Apocrine ordiferous gland located in annogential and axillary armpit areas Activated after puberty The secreted product itself does not stink but does emit an odor when combined with the bacteria present on the skin Secrete viscous yellowish fluid onto hair follicles iii Ceruminous glands specialized sweat glands located in the lining of the external ear canal Secrete a bitter substance called cerumen earwax to prevent entry of foreign objects such as insects and water into the ear iv Mammary glands specialized sweat glands in breasts that secrete milk to feed the young b Sebaceous gland oil glands simple alveolar glands Located everywhere in body except in palms soles Secretes sebum into hair follicles and via pores to the surface of the skin to keep the hair skin moisturized oily to prevent water loss c Hairs pili protects against trauma and insulates the body in cold weather i 2 regions 1 Shaft above skin surface Flat or ribbon like is curly hair Oval is wavy hair Round is straight hair Highly keratinized dead cells 2 Root below skin surface enclosed in hair follicle Hair follicle also contains hair matrix Cells in the matrix constantly undergo mitosis forming 3 concentric rings medulla cortex and cuticle The base of hair follicles re wrapped by root hair plexus which acts like touch receptors when hair is bent d Acid mantle sweat contributes to the protective function of the skin Skin pH level is between 4 6 levels It is a very fine slightly acidic film sweat covering the skin to protect it from microorganisms 6 Name and discuss the 3 types of burns a First degree burn partial thickness burn damage to the epidermis and no b Second degree burn partial thickness burn damage to papillary layer of treatment necessary dermis blister formation c Third degree burn full thickness burn destruction of entire epidermis and dermis and occasionally hypodermis intermediate treatment necessary to prevent pathogenic infection and to supply water and electrolytes lost in the burn due to loss of epidermis 7 Name and define the 3 major types with skin cancer a Basal cell carcinoma proliferation in stratum basale least malignant and b Squamous cell carcinoma stratum spinosum second most common grows most common slow growth rapidly c Melanoma proliferation of the melanocytes cell producing melanin which provides protection against UV radiation most aggressive highly metastatic and resistant to chemotherapy least common B Skeletal System 1 Compare and contrast compact and spongy bone tissues a Compact bone is located on the exterior part of bone Compact bones are composed of osteons Has concentric rings called lamellae haversian canal center of osteon and contains blood vessels b Spongy bone is located in the interior part of bone Composed of needle like structure called trabeculae c Both contain blood vessels 2 Name and describe the 4 structural classes of bones What are sesamoid bones Give an example of each class a long bones composed of diaphysis shaft and 2 epiphysis expanded ends of the long bones at the end of epiphyseal plates in children show remnants of hyaline cartilage Mostly in the appendicular skeleton phalanges are long bones too i surrounded by medullary cavity 1 red bone marrow in children produces blood cells and platelets 2 yellow bone marrow in adults does not produce blood cells and in children platelets b short bones appear roughly cuboidal located in wrists carpals and ankles c d e tarsals sesamoid bones flat bones sternum protect internal organs ex cranial vaults protects brain irregular bones bones that are not classified in
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