Exam 2 study guide - Dr. Thompson PDF

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Chapter 5: The Integumentary System A) Name the tissue types composing the epidermis and dermis. List the major layers of each and describe the functions of each layer. a. Epidermis: i. Keratinocyte: produces soft keratin; connected by desmosomes; arise in the DEEPEST layer of the epidermis (stratum basale); dead at surface-turnover 25-45 days ii. Melanocyte: synthesize & secrete melanin; arise in DEEPEST layer of the epidermis (stratum basale) iii. Langerhans cells: macrophage cells; activate immune system (sit in epidermis outside cardiovascular system & serve as a barrier to keep foreign material out; if we have an injury these cells help secrete Chemoattractants that bring WBCs to sit of injury iv. Merkel cells: receptor for touch; found at epidermal-dermal junction; associated with sensory nerve endings b. Layers of Epidermis: i. Stratum corneum: gets nutrients SLOWEST; OUTTERMOST layer that we see; all dead cells; no organelles; bags of KERATIN- flat squamous appearance ii. Stratum lucidum: ONLY IN THICK SKIN: palms of hands & soles of feet- an extra layer so not everywhere iii. Stratum granulosum: keratinization begins; organelles & cells start to die; still connected via desmosomes iv. Stratum spinosum: where soft keratin is produced which makes the other keratin above harder as they move outward v. Stratum basale: gets nutrients FASTEST; INNERMOST layer; all metabolic active cells; produce all above layers; 10-25% are melanocytes which secrete melanin into extracellular matrix, merkel cells attached to a sensory nerve. c. Dermis: i. Made of cells found in connective tissue proper: fibroblasts, macrophages, mast cells, WBCs. Fibroblasts: lay down collagen d. Layers of Dermis: i. Papillary layer: TOP 20% layer; loose AREOLAR connective tissue 1. Superior surface is put into peglike projections called DERMAL PAPILLAE a. Responsible for fingerprints ii. Reticular layer: BOTTOM 80% layer; DENSE IRREGULAR connective tissue 1. Cleavage lines form between separations between bundles of collagen fibers a. Incisions made PARALLEL to cleavage lines heal better e. Hypodermis: NOT part of skin B) Describe the factors that normally contribute to skin color. Briefly describe how changes in skin color may be used as clinical signs of certain states. a. Melanin: only made in the skin b. Carotene: by orange plants c. Hemoglobin: in RBCs circulating through dermal capillaries d. Changes in skin color: i. Blue skin = cyanosis due to poorly oxygenated hemoglobin

C) Compare the structure and locations of sweat and oil glands. Also compare the composition and function of their secretions. a. Sweat glands: everywhere except nipples & external genitalia i. Eccrine sweat glands (merocrine): most abundant- palms, sole of feet, forehead 1. Secrete sweat: 99% H2O, some NaCl, acidic- reduces bacterial growth on skin; responsible for thermoregulation ii. Apocrine sweat glands: not in pre-puberty kids; in armpits & anogenital area 1. Body odor due to bacteria that break down apocrine sweat glands; no role in thermoregulation iii. Mammary gland: produce milk iv. Ceruminous glands: produce ear wax b. Oil glands: all over body except palms & soles of feet; secrete sebum = oily substance i. Holocrine = “puking” cell ii. Function in lubrication, prevent water loss, slightly acidic – kill bacteria grown on skin iii. Gland is initiated & maintained by androgens= precursor to sex hormones D) List the parts of a hair follicle and explain the function of each part. Also describe the functional relationship of arector pili muscles to the hair follicles. a. Hair i. Shaft: keratinization is complete ii. Root: keratinization is ongoing iii. Hard keratin iv. 3 layers: 1. Medulla- innermost 2. Cortex- surrounds medulla 3. Cuticle- outermost; loss of cuticle at the top of the hair shaft causes split ends b. Arrector pili: responsible for “hair-rising” and goose bumps when it contracts & pulls the hair follicle into an upright position. E) Names the regions of a hair and explain the basis of hair color. Describe the distribution, growth, replacement, and changing nature of hair during the life span. a. Vellus hair: body hair of children & adult females; FINE & pale b. Terminal hair: eyebrows & scalp hair; COARSE, longer & darker; appears at puberty in axillary, public regions, face, & chest. c. Growth i. 2.5mm/week ii. Active growth phase is follow by a regressive phase- old hair is pushed out by new hair iii. We lose ~ 90 hairs per day d. Alopecia: hair thinning e. True, or frank, baldness: i. Most common: Male pattern baldness 1. Genetically determine & sex-influenced condition 2. Caused by follicular response to DHT- dihydrotestosterone F) Describe how the skin accomplishes the 6 different functions. a. Protection b. Body Temperature regulation c. Cutaneous sensation

d. Metabolic functions e. Blood reservoir f. Excretion G) Summarize the characteristics of the 3 different major types of skin cancers. a. Basal Cell Carcinoma: LEAST malignant; MOST common (80%) i. Stratum basale cells proliferate & invade dermis ii. Occur commonly in sun exposed areas, curable b. Squamous Cell Carcinoma: SECOND MOST common i. Arises from keratinocytes of the stratum spinosum ii. Grows rapidly, metastasized if not removed, good outcome if caught early c. Melanoma: MOST malignant; LEAST common i. Highly metastatic ii. Resistant to chemotherapy iii. Cancer of melanocytes iv. 1/3 from pre-exsisting moles d. Rule of thumb to identify skin cancer: ABCD RULE i. Asymmetry ii. Border irregularity iii. Color iv. Diameter H) Explain why serious burns are life threatening. Describe how to determine the extent of a burn and differentiate first, second, and third degree burns. a. 1st degree: only the epidermis is damaged i. Symptoms: localized redness, swelling, pain b. 2nd degree: epidermis & upper regions of dermis are damaged i. Symptoms: blisters, like 1st degree burns rd c. 3 degree: entire thickness of the skin is damaged i. Symptoms: gray-white, cherry red, or black burned area; no initial edema/pain d. Rule of thumb to quantify area burned: i. Critical: more than 25% of body has 2nd degree burns, over 10% has 3rd degree, 3rd degree burns on face, hands, or feet e. Rule of Nines: divide the body into 11 regions (9% each) to estimate BODY FLUID LOST Chapter 6: Bones and Skeletal Tissues A) Describe composition, function and location of the 3 types of cartilages. a. Hyaline: MOST abundant i. Provide support but is flexible ii. Secretes a lot of ground substance which gives it a smooth, slick appearance iii. In costal cartilage of ribs, larynx, nose b. Elastic: like hyaline i. Withstands repeated stretching ii. Only in Ear & Epiglottis c. Fibrocartilage: Very tough i. Highly compressible & have great tensile strength ii. In vertebrae, meniscus of knee, pubic bone B) Distinguish between the 2 types of cartilage growth. a. Appositional growth: growth from OUTSIDE i. Cartilage forming cells secrete new matrix on external face

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b. Interstitial growth: growth from INSIDE i. Lacunae bound chondrocytes divide & secrete new matrix, expanding the cartilage from within Compare and contrast the structure of the four bone classes and provide examples for each class. a. Long bones: longer than they are wide b. Short bones: cube shaped- wrist & ankle i. Sesamoid bones: form within tendons- patella c. Flat bones: thin, flattened, a bit curved- sternum & skull bones d. Irregular bones: bones with complicated shapes- vertebrae & hip bones List and describe the functions, classifications, and landmarks of bone. a. Functions: i. Support: support organs ii. Protection: protects brain, spinal cord, rib cage iii. Movement: act as levers for muscles to act on iv. Mineral & fat storage: calcium & phosphate release & storage v. Blood cell formation: hematopoiesis within marrow cavities b. Classification: i. Long, short, flat, or irregular c. Landmarks: i. Projections: sites of muscle & ligament attachment; help form joints ii. Depressions: passage of blood vessels & nerves iii. Openings: passage of blood vessels & nerves Distinguish between 2 types of bone. a. Compact bone: hard, smooth exterior, very dense b. Spongy bone: NOT soft, looks like a spongy because of bony processes running in different directions i. Bony processes are called TRABECULAE Describe the gross anatomy of a typical long bone and a flat bone. Indicate the locations and functions of red and yellow marrow, articular cartilage, periosteum, and endosteum. a. Long bone: 1 diaphysis & 2 epiphyses i. Diaphysis: 1. Tubular shaft that forms the axis of long bones 2. Thick collar of compact bone surrounding a central medullary cavity 3. YELLOW bone marrow (fat): in medullary cavity of ADULTS 4. RED bone marrow: in medullary cavity of CHILDREN ii. Epiphyses: 1. Ends of long bones; spongy bone is encased in compact bone 2. Exterior is compact bone, interior is spongy bone 3. Joint surface is covered in articular cartilage (hyaline cartilage)- articular surface because bones articulate (move) iii. Epiphyseal line: 1. Between diaphysis & each epiphysis of an ADULT long bone iv. Epiphyseal plate: 1. Separates the diaphysis from the epiphyses- denotes where your growth plate used to be 2. Made of hyaline cartilage

3. Eventually, formation of bone seals the cartilage & vertical growth occurs v. Membranes: 1. Periosteum: EXTERNAL surface a. Outer fibrous layer: dense irregular connective tissue b. Inner osteogenic layer: osteoblasts & osteoclasts i. Osteoblast: bone-forming cells (from osteogenic cells) ii. Osteoclasts: bone-destroying cells 2. Endosteum: covers internal bone surfaces a. Convers trabeculae of spongy bones & lines the canals that pass through the compact bone b. Contains both osteoblasts & osteoclasts b. Flat bone: i. Thin plates of periosteum-covered compact bone on the outside ii. Thin plates of endosteum-covered spongy bone on the inside iii. No shaft, no epiphyses iv. Spongy bone is called the DIPLOE: where RED marrow is found v. No significant marrow cavity, but bone marrow in present between trabeculae G) Describe the histology of compact and spongy bone. a. Compact bone: i. Made of OSTEON: 1. Hollow tubes of bone matrix called LAMELLA a. Layers of collagen fibers 2. Haversian canal- allows blood vessels or nerve endings to move vertically through the compact bone; VERTICAL canals 3. Volkmann’s canal- channels lying at right angles to the central canal, connecting the blood & nerve supply to the periosteum to that of the Haversian canal; HORIZONTAL canal 4. Osteocytes occupy lacunae at the junctions of the lamellae a. Osteocytes: MAINTAIN bone matrix b. They reside in the lacuna & their projections lie in the canaliculus b. Spongy bone: i. NO osteons ii. Trabeculae contain irregularly arranged lamellae & osteocytes interconnected by canaliculi. iii. Nutrients reach the osteocytes of spongy bone by diffusing through the canaliculi from capillaries in the endosteum around the trabeculae H) Discuss the chemical composition of bone and advantages conferred by the organic and inorganic componenets. a. Organic componenets: i. Osteogenic cells: stem cell ii. Osteoblasts: makes new bone; encases itself in bone & then becomes  iii. Osteocytes: maintains the bone matrix iv. Osteoclasts: break down bone v. Osteoid: ground substance & collagen fibers made & secreted by osteoblasts b. Inorganic components:

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i. Hydroxyapatites = mineral salts 1. 65% by mass; mainly calcium phosphates; responsible for bone hardness & its resistance to compression Compare and contrast intramembranous and endochondral ossification a. Ossification = osteogenesis: to make new bone i. Formation of bony skeleton – in embryo ii. Bone growth – until adulthood iii. Bone remodeling & repair – Adults b. Intramembranous ossification: bone developing from a fibrous membrane Bone is called = membrane bone i. Mesenchymal cells cluster & differentiate into osteoblasts, forming an ossification center ii. Osteoid (bone matrix) is secreted by osteoblasts within the fibrous membrane & calcifies; trapped osteoblasts become osteocytes iii. Accumulating osteoid is laid down between blood vessels in a random manner forming the trabeculae called woven bone iv. Vascularized mesenchyme condenses on the external surface of woven bone & becomes periosteum v. Trabeculae deep in the periosteum thicken & are later replaced with mature lamellar bone, forming compact bone plates vi. Spongy bone (dipole), consisting of distinct trabeculae, stays internally & its vascular tissue becomes RED bone marrow c. Endochondral ossification: bone development by replacing hyaline cartilage Bone is called = cartilage/endochondral bone i. Osteoblasts of the newly converted periosteum secrete osteoid against the hyaline cartilage forming a bone collar ii. As bone collar forms, chondrocytes within the shaft enlarge & signal cartilage matrix around to calcify iii. Chondrocytes die & matrix begins to deteriorate, opening up cavities. iv. Elsewhere, healthy cartilage continues to grow slowly, causing the cartilage model to grow v. Periosteal bud invades the internal forming cavities vi. Osteoclasts erode the calcified cartilage matrix  osteoblasts secrete osteoid around remaining fragments of cartilage forming trabeculae  spongy bone develops vii. Osteoclasts break down the newly formed spongy bone & open up a medullary cavity in the center of the diaphysis & ossification continues viii. Secondary ossification centers appear in the epiphyses in preparation for next stage- no medullary cavity forms in the epiphyses ix. After 2ndary ossification is complete, hyaline cartilage remains only in articular cartilages & epiphyseal plates Describe the process of long bone growth that occurs at the epiphyseal plates. a. 1. Proliferation zone: cartilage cells undergo mitosis b. 2. Hypertrophic zone: older cartilage cells enlarge c. 3. Calcification zone: matrix calcifies; cartilage cells die; matrix begins deteriorating d. 4. Ossification zone: osteoblasts make new bone by mineralizing collagen

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**LONGITUDNAL Growth ENDS when epiphysis & diaphysis fuse- Chondroblasts of epiphyseal plate divide less often & plates become thinner & thinner until they are entirely replaced by bone tissue** bones can still grow in WIDTH (thickness) Compare the locations and remodeling functions of the osteoblasts, osteocytes and osteoclasts. a. Osteoblasts: new bone formation; deposit bone when bone is injured or added bone strength is required b. Osteoclasts: breakdown of bone; resorption of bone i. Raise blood calcium levels ii. Remove necrotic debris 1. Lysosomal enzymes: digest organic matrix 2. Hydrochloric acid: convert calcium salts into soluble form c. Osteocytes: maintain bone matrix Explain how hormones and physical stress regulate bone remodeling. a. Hormones: Parathyroid hormones PTH: released when blood levels of ionic calcium decline, osteoclasts resorb bone releasing calcium to the blood, as blood concentrations of calcium rise, stimulus to release PTH ends. i. Calcitonin: lowers blood calcium temporarily when taken in high doses b. Stress: higher mechanical stress, more osteoblasts, more collagen to mineralize i. Wolff’s law: bones grow or remodel in response to demands placed on them Describe the steps of fracture repair. a. 1. Hematoma formation: clot forms, injured cells die, tissue becomes swollen & painful b. 2. Fibrocartilaginous callus forms: soft callus forms, capillaries form, fibroblasts & osteoblasts begin reconstructing bone, chondroblasts secrete cartilage matrix c. 3. Bony callus formation: spongy bone forms until ends of bones are connected d. 4. Bone remodeling: begins with bony callus formation, excess material on diaphysis exterior & within medullary cavity is removed & compact bone is laid down to reconstruct the shaft walls. Contrast the disorders of bone remodeling seen in osteoporosis, osteomalacia, and Paget’s disease. a. Osteoporosis: bone resorption is greater than bone deposit i. Common in spongy bone of spine & femur neck ii. Treated with vitamin D supplements & HRT (hormone replacement therapy) b. Osteomalacia: soft bones: bones are inadequately mineralized (normal production of osteoid) i. Pain when weighted ii. Rickets in children iii. Bow legs, deformities to pelvis, skull, & ribcage iv. Treated with vitamin D increase c. Pagets Disease: excessive bone formation & breakdown i. Abnormal ration of spongy to compact bone 1. Poor mineralization of new bone

Chapter 9: Muscles and Muscle Tissue A) Compare and contrast the basic types of muscle tissue. a. Skeletal: most abundant; striated muscle; voluntary muscle i. Myoblasts: single nucleated cells 1. Mitotic, stem cells for muscles

ii. Multinucleated myotube: fused myoblasts; not visible striations; not too many contractile proteins iii. Myofiber: visible striations; develops a lot of contractile proteins iv. Determined myoblast: a muscle precursor cell that can go through mitosis, replicate over & over 1. Many of these together making contact with membranes produce junctions & become a differentiated myotube- nuclei here CAN’T undergo mitosis 2. If we want more nuclei in order for muscle fibers to grow, we add myoblasts b. Cardiac: involuntary i. Very small fibers ii. Striated iii. Contracts at a steady rate c. Smooth: involuntary i. No striations ii. Mononucleated iii. Only muscle cell that can go through mitosis & cytokinesis B) List 4 important functions of muscle tissue. a. Excitability, or irritability b. Contractility c. Extensibility d. Elasticity C) Describe the gross structure of skeletal muscle. a. Muscle (organ) i. Epimysium ii. Fascicle b. Fasicle (portion of muscle) i. Perimysium ii. Muscle fiber (cell) c. Muscle fiber (cell) i. Multiple nuclei ii. Striations iii. Sarcolemma surrounded by its own endomysium iv. Myofibril d. Myofibril or fibril i. Made up of multiple sarcomeres, strung together in series e. Sarcomere i. Smallest unit of the skeletal muscle ii. Muscle shortening occurs here f. Myofilament or filament i. Thick or thin types ii. Thick have bundled myosin molecules; thin have actin molecules iii. Sliding of thin past the thick produces muscle shortening D) Describe the microscopic structure and functional roles of the myofibrils, sarcoplasmic reticulum, and t-tubules of skeletal muscle fibers. a. Myofibrils: rodlike that occupy 80% of muscle cell volume i. Composed of sarcomeres arranged end to end

1. Smaller rodlike structures called myofilaments make up sarcomere b. Sarcoplasmic reticulum: loosely surround each myofibril i. Regulate intracellular levels of ionic calcium- stores calcium & releases it on demand when muscle fiber is stimulated to contract c. T-tubules: tube formed at each A band-I band junction i. Conduct impulses to the deepest regions of the muscle cell & every sarcomere ii. Impulses signal for the release of calcium from adjacent terminal cisternae. E) Describe the sliding filament theory. a. During contraction the THIN filaments side past the THICK filaments so that ACTIN & MYSOIN filaments overlap to a greater degree b. In relaxed muscle fiber, thick & thin filaments overlap only at the ENDS of the A band c. MYOSIN heads on THICK filaments latch onto myosin binding sites on ACTIN in THIN filaments & sliding begins d. As muscle cell SHORTENS: i. I band shortens  distance between Z discs is reduced  H zones disappear  A bands move closer but do NOT change in length F) Explain how muscle fibers are stimulated to contract by describing events that occur at the neuromuscular junction. a. 1. Action potential arrives at axon terminal of motor neuron b. 2. Voltage gated Ca channels open & Ca enters the axon terminal c. 3. Ca entry causes some synaptic vesicles to release their contents (ACH) by exocytosis d. 4. ACH diffuses across the synaptic cleft & binds to receptors in the sarcolemma e. 5. ACH binding opens Ligand gated ion channels that allow passage of Na INTO the muscle fiber & K OUT of the muscle fiber. i. More Na ions enter than K ions leave = change in membrane potential (DEPOLARIZATION) f. 6. ACH effects are terminated by its enzymatic breakdown in the synaptic cleft by acetylcholinesterase ...