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Chapter 7 Structure & Function of Human Body OBJECT IVES Students should be able to: • Understand and explain the difference between anatomy, physiology, and pathophysiology. • Define what determines a state of wellness as opposed to illness. • Describe the primary anatomical features and physiological actions of the systems for movement & protection of the body. • Name common diseases or disorders associated with each system. • Describe the behaviors and actions for each body system that promote health and prevent major diseases and disorders. Definitions Anatomy: = study of the form & structure of an organism, such as the names & locations of bones, muscles, & organs. Anatomy comes from 2 words: Ana which means “up or apart” Tomos which means “to cut” “The Anatomy Lesson of Dr Nicolaes Tulp” by Rembrandt in 1632 Definitions Physiology: = study of the functions (how and why something works) of the body’s structures. Definitions Disease: = abnormal conditions in the body are called diseases. When an abnormality occurs it is referred to as a pathophysiology (patho = disease). Definitions Pathophysiology: = is the study of why diseases occur & how the body changes in function in rx to diseases. Definitions cont. Etiology: = study of the causes of diseases. Diseases have a variety of causes. Ex’s: Bact, viruses, hazards, & personal habits. Signs: • objective evidence of an illness • Means health care professional can observe them Symptoms: • Subjective • cannot be directly observed by health care professional but are reported by patient Definitions Syndrome: = not a precise disease but a group of related signs & symptoms Definitions cont. Diagnosis: • Name of the Disease or Syndrome Diagnostic procedures: • Tests performed to determine the diagnosis Definitions cont. Treatment = Meds or procedures used to control or cure the disease. Common treatments include surgery, exercise, & special diets. Definitions cont. Prognosis • Prediction of possible outcome of the disease & potential for recovery. Prevention • Behaviors that promote health & prevent disease Definitions cont. Wellness • state of wellness is experienced when the body maintains homeostasis. Illness • state of illness occurs when 1 or more of the body's control systems lose ability to maintain homeostasis Definitions cont. Prevention of Illness organized into 3 levels: 1) Primary • • Prevent initial occurrence of disease or injury by maintaining homeostasis. Ex of how to: Practicing good lifestyle habits avoiding exposure to bact & viruses 2) Secondary • Treat conditions that do occur as quickly as possible to prevent further damage. 3) Tertiary • Rehabilitate to allow person to regain as much fx as possible & prevent further disability. Question • Which of the following is an example of objective data? A. Headache B. High blood pressure C. Numbness in arm B. High blood pressure Body System: Body system = When 2 or more organs combine to perform major body function • Systems work together (Interrelated) to maintain homeostasis or wellness Body Systems Systems providing Movement & Protection are: Skeletal, Muscular, & Integumentary Systems – Provide support – Allow movement – Protect body The Integumentary System Integumentary System Largest organ in body 15% of body wt surface area ~ 25 ft2 in adult consists of Skin & its Appendages, which include: Hair, nails, sweat glands, & oil glands Integumentary System • Protects from environmental hazards, such as: sunrays bacteria Heat, cold, pain, pressure • Helps controls body temp via sweating & vasoconstricting/dilating BV’s • Prevents dehydration by acting as waterproof membrane • helps maint Homeostasis Layers of the Skin • Epidermis • Dermis • Subcutaneous tissue Epidermis • =‘s outer layer of , consisting: of 5 – 6 layers c no blood supply or nerves outermost layer composed of cells (squamous) that have died from environ exposure & are shed daily shed cells are replaced c cells produced in lower layers thru out lifetime About 500 million squamous cells are lost every day Fascinating Facts • Humans shed ~ 600,000 particles of skin q hr, which is ~ 1.5 lbs per yr. • By age 70, ave person will have lost 105 lbs of skin. • Humans shed & re-grow outer skin cells ~ q 27 days. That totals ~ 1000 new skins in a lifetime. Epidermis & Skin Pigmentation • Skin pigmentation determined by Melanocytes that produce pigment Melanin. • Melanocytes loc’d lower epidermis • Melanin can be black, brown, or yellow, depending upon racial origin • amt of melanin (& other skin pigments such as carotene & hemoglobin) in melanocytes determines shades of human skin. Epidermis & Skin Pigmentation • Patches of melanin = Freckles or, if related to damaged skin areas, "age spots.“ • Albino = person who has no skin pigmentation. Dermis • 2nd layer of skin • contains invol. muscles (arrector pili muscles cause "goose bumps"), BV’s, nerves, hair follicles, sudoriferous (sweat) glands, & sebaceous (oil) glands. Subcutaneous Tissue • innermost layer of skin • contains fat & connective tissue (CT), which fastens skin to underlying muscles Skin Structures Skin Appendages: Hair • each hair encased in (sits in) a hair follicle & ends in a root where new hair growth occurs. •composed of a fibrous protein called keratin, which is a nonliving cell, so haircuts are not painful Skin Appendages: Nails • Fingernails & Toenails also made of keratin • growth of the nail occurs at the base of nail under the half-moon shaped area • fx of nails is to protect fingers & toes Skin Appendages: Sudoriferous (Sweat) Glands • during perspiration, water mixed c salt & waste products are excr’d thru sweat glands • fx is to excrete excess water & assist in cooling body by evaporation of water from skin Skin Appendages: Sebaceous (Oil) Glands • excrete oily substance (sebum) to lubricate & protect skin • Sebum is slightly acidic, so it discourages growth of bacteria. Fascinating Facts • fingernail or toenail takes ~ 6 months to grow from base to tip • beards are fastest growing hairs on body. If never trimmed, beard could grow to 30 feet in length over ave lifetime • 45 miles of nerves just in the skin of a human The Skin Animation Click Here to Play The Skin Animation Diseases & Disorders of Skin Athlete's foot: • infection of skin caused by a fungus Fungus under Microscope Diseases & Disorders of Skin Boils (furuncles): • bacterial infection of hair follicles or sebaceous glands. Diseases & Disorders of Skin Skin Cancer: 3 forms 1. Basal Cell • most common & easiest to treat 2. Squamous Cell • more serious 3. Melanoma • most serious & can be life-threatening Diseases & Disorders of Skin Cellulitis • bacterial infection of dermis & subcut layers of skin Diseases & Disorders of Skin Pressure Sores = Bed Sores = Decubitus Ulcers: • areas of skin breakdown that occur over bony prominence due to excessive & prolonged pressure that prevents adequate circ to tissues. Diseases & Disorders of Skin Dermatitis: • general name for inflammation of skin • Contact dermatitis = allergic rx to a substance that makes contact c skin Diseases & Disorders of Skin Eczema: • is a generalized skin irritation usu’ly caused by an irritant • appears as reddened areas on surface skin Diseases & Disorders of Skin Psoriasis: • chronic, noncontagious, inherited skin dis, in which too many epithelial cells are produced. Diseases & Disorders of Skin Warts: • caused by viral infection of skin. Integumentary System – Preventive Measures • good hygiene & keep skin clean • Do not break open pimples or other growths on skin. • Do not scratch insect bites or other irritations • Avoid excessive exposure to sun • Use sunscreen & wear a hat when in sun • Have skin changes checked immediately. • Protect skin from poisonous plants & insect bites. • Get adequate amounts of vit’s A & C & niacin Integumentary System – Age Related Changes • Decr’d: Elasticity of the skin, subcutaneous fat (insulation), and hair (head, face) • Incr’d: Dryness, wrinkles, skin pigmentation, and susceptibility to irritation Question • Which of the following is the outer layer of skin? A. Dermis B. Subcutaneous C. Epidermis