Bio 425 Lecture Exam 2 Study Notes.docx - Bio 425 Lecture...

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Bio 425 Lecture Exam 2 Study Notes1. Muscle Comparison Chart2. Nervous Tissue:specialized for communication by means of electrical and chemical glands. It consists of:TypeFunctionLocationNeuron (nerve cells)They detect stimuli, respond quickly and transmit coded information rapidly toother cells.Brain, spinal cord, nerves and ganglia (knot-like swellings inthe nerves).Neuroglia or Glial cellsNon-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the centraland peripheral nervous systems. The parenchyma of brain and spinal cord.
3. Types of membranesNameAppearanceFunctionLocationCutaneous membrane (aka the skin)Relatively dry. Stratified squamous epithelium resting on a layer of connective tissue.Resists dehydration of the body and providesan inhospitable environmentfor the growth of infectious organisms.Skin; external
Mucous MembraneTwo to three layers :epitheliumlamina propria (an areolar connective tissue)muscularis muscosae (a layerof smooth muscle).Lines the passages that open to the exterior environment; have absorptive, secretory and protective functions; traps bacteria and foreign particles. Digestive, respiratory, urinary and reproductive tracts.Serous Membrane (serosa) Simple squamous epithelium resting on a thin layer of areolar connective tissueLine the insides of some body cavities and form a smooth outer surface on some of the viscera. The pleurae, pericardium and peritoneum.Serous membranes produce watery serous fluid, which arises from the blood and derives its name from the fact that it’s similar to blood serum in composition.Tunica interna of the blood vessels andendocardium of the heart are membranes made up of a simple squamous epithelium called endothelium. Endothelium rests on a thin layer of areolar tissue, which often rests in turn on an elastic sheet.4. Integumentary System: consists of the skin and its accessory organs-the hair, nails and cutaneous glands. The study of the integumentary system is Dermatology.The skin is the body’s largest and heaviest organ.The skin consists of two layers: epidermis and dermis.Thick skin covers the palms, soles and surfaces of the fingers and toes. Thick skin has a layer of dead cells called the stratum corneum.
Thick skin has sweat glands but no hair follicles or sebaceous (oil) glands.The rest of the body is covered with thin skin, which has anepidermis with a thin stratum corneum. Thin skin has hair follicles, sebaceous glands and sweat glands.Functions of the skin:Resistance in Trauma and Infection- the epidermal cells are packed with keratin and linked by desmosomes that give it its durability. Bacteria and fungi are kept in check by the skin’s dryness; its slight acidity and antimicrobial peptides called dermcidin and defensins.Barrier Functions- skin is a barrier to water. It prevents the body from absorbing excess water and from losing excess water. The epidermis is also a barrier to UV rays and to harmful chemicals.

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