Unit 2 Final Exam Anatomy I Notes PDF

**Unit 2 final exam overview:** **Integumentary system:** **Structures of the system:** - Skin - Hair - Nails - Glands **Functions:** - Protection -- protects against U V light, microorganisms, water loss. - Sensation -- sensory receptors for heat, cold, touch, pressure,...

**Unit 2 final exam overview:** **Integumentary system:** **Structures of the system:** - Skin - Hair - Nails - Glands **Functions:** - Protection -- protects against U V light, microorganisms, water loss. - Sensation -- sensory receptors for heat, cold, touch, pressure, pain. - Temperature regulation -- modulation of blood flow through the skin and activity of sweat glands. - Vitamin D production from a molecule made in the skin when exposed to U V light. - Excretion -- small amounts of waste products eliminated. **Layers of the skin:** - Epidermis - Dermis - Subcutaneous **Epidermis:** - thin, outermost layer of the skin, made up of stratified squamous epithelium. - It is avascular, meaning it lacks a blood supply. Therefore, it relies on the diffusion of oxygen and nutrients from the underlying dermis. - This layer serves as the body's main barrier, protecting against environmental threats. - Keratinization is the process by which skin cells harden and flatten as they move from the lower layers of the epidermis toward the surface. - During this process, cells accumulate keratin, a protective protein, which helps to form a tough, water-resistant layer on the skin's surface. - The epidermis consists of five distinct layers, two of which are: - Stratum corneum: The outermost layer composed of dead, keratinized cells that provide a protective barrier. - Stratum germinativum (also known as the basal layer): The deepest layer where new skin cells are generated before moving up through the other layers. **Epidermal cells:** - **Keratinocytes:** Majority of cells, produce keratin for strength. - **Melanocytes:** Responsible for skin color, produce melanin that is transferred to keratinocytes. All people have the same number of melanocytes. - **Langerhans cells:** Part of the immune system. - **Merkel cells:** Detect light touch and superficial pressure. **Keratinization:** - Process where cells move outward through layers, fill with keratin, die, and form a layer that resists abrasion and acts as a permeability barrier. - **Stratum Basale** **- Stratum spinosum** \- Multi layers of many slided cells that flatten as they pushed upward \- Contain new desmosomes, lipid filled lamellar bodies. And keratin fibers **- Stratum granulosum** \- two layers of flattened shaped cells \- Contains protein granules of keratohyalin that accumulates in the cytoplasm \- Lamellar bodies move to the plasma membrane and release their lipid contents into extracellular space \- Nucleus and other organelles degenerate and cell dies \- The keratin fibers and keratohyalin granules do not degenerate **- Stratum Lucidum** \- Thin clear zone of dead keratinocytes \- found only in palms and soles **- Stratum Corneum** \- Most superficial layer of dead squamous cells joined by desmosomes called cornified cells \- have a soft protein envelop of keratin and mixture of keratin fiber and keratohyalin. **Thick skin:** - Has all 5 epithelial strata - Found in areas subjects to pressure or friction - Palms of hands, fingertips, soles of feet - Fingerprints and footprint **Thin skin:** - Composed of 4 strata - No stratum lucidum - Covers rest of bod - Hair grows here **Skin color determined by:** - Pigments in the skin - Blood circulating through the skin - The thickness of stratum corneum - Type of the melanin produced - Amount of melanin - Size, distribution, and number of melanosomes - Hormones **Pigments:** - **Melanin:** provides for protection against UV light. Colored brown to brown, yellow, black, yellowish, or reddish. Melanosomes processes extend between keratocytes, deposit melanosomes. - **Carotene:** yellow pigment from vegetables, accumulates in stratum corneum, in adipose cells of dermis, and in subcutaneous tissues. **Melanin transfer to keratinocytes:** - Melanocytes produce melanin into melanosomes - Melanosomes move into melanocytes - Melanocytes move into keratinocytes **Dermis:** - Gives structural strength - Has fibers collagen, elastic, reticular, fibroblast, macrophages, and adipocytes - Contains nerves, blood vessels, hair follicles, smooth muscles, glands, and lymphatic vessels. - Sensory functions: pain, itch, tickle, temperature, touch, pressure. **Layers of dermis:** - **Papillary:** superficial, areolar with lots of elastic fibers, dermal papillae. Touch receptors, free nerve endings sensing pain. - **Reticular:** deep, dense irregular, collagen, and elastic fibers, contains adipose tissue, hair follicles, nerves, oil glands, ducts of sweat glands, heat sensors. **Cleavage lines:** - Elastic and collagen fibers oriented in some directions more than in others - Important in surgery **Subcutaneous tissue (hypodermis):** - Deep to skin - Contains loose connective tissue with collagen and elastic fibers - **Cells:** fibroblasts, adipose cells, macrophages - Adipose tissue - **Functions:** energy source, insolation, padding **Hair:** - Found everywhere except palms, lips, nipples, fingers, and toes - Shaft: above skin surface - Root: located below the surface - Hair bulb: base of hair root - Layers: - cortex: forms bulk of hair - matrix: is source of hair - dermis projects into bulb as hair papilla, serves as a blood supply - hair follicle contains stratum Basale that remain after injury a supply a source of new epidermis **Hair color:** - caused by varying amount and types of melanin - genes **Muscles:** - arrector pill: smooth muscle - contraction causes hair to "stand on end" - producing goose bumps **Glands:** - **sebaceous gland:** - **eccrine glands:** - **apocrine glands:** - **ceruminous gland:** - **mammary glands:** **Nail:** - thin plate of layers of dead stratum corneum cells with hard keratin - nail body: stratum corneum, visible portion. - Cuticle: corneum superficial to nail body - Matrix and nail bed: cells that give rise to the nail - Nail root: covered by skin, extends from nail matrix - Lunula: small part of nail matrix seen trough the nail body. **Protection:** - Melanin against UV radiation - Hair is insulator and protection against light - Eyebrows keep sweat out of the eyes - Eyelashes protects eyes from foreign objects - Hair in nose and ear against dust, bugs - Nails protect ends of digits, self defense - Skin acts as barrier to diffusion of water **Sensation:** - Pressure, temperature, pain, heat, cold, touch, movement of hairs **Temperature regulation:** - Sweating and radiation - Sweat causes evaporative cooling - Arterioles in dermis change diameter as temperature changes. Blood flows through the dermis **Heat exchange in the skin:** - **Heat loss increase (evaporation):** results in a reduction in body temperature, more warm blood flows from deeper structures to the skin. Temperature increases because of exercise fewer. To maintain homeostasis, this excess must be lost, which is accomplished by sweat. - **Heat loss decreases:** less warm blood flows from deeper structures to the skin, resulting in reduced flow through the skin, heat loss decreases. If body temperature drops below normal, diameter of the dermal blood vessels decreases. **Aging:** - Epidermis thins and amount of collagen decreases - More likely skin infections - Wrinkling occurs due to decrease in elastic fibers - Drier skin - Decrease in blood supply - Poor ability to regulate body temperature - Melanocytes decreases - Increased melanin production - Sunlight ages skin more rapidly **Skeletal system:** **Structures of skeletal system:** - Bones - Cartilage - Tendons - Ligaments **Functions:** - Provides framework - Gives shape - Supports weight of body - Support and protect organs - Blood cell production - Storage - Endocrine regulation **Cartilage:** - Hyaline, fibrocartilage, and elastic cartilage - Chondroblast: form matrix - Chondrocytes: surrounded by matrix, are within lacunae - Matrix: collagen fibers for strength, proteoglycans for resiliency - Perichondrium: double layered, covers cartilage except at articulations, has fibers, contains chondroblasts, blood vessels and nerves. - No blood vessels - **Articular cartilage**: covers bones at joints, has no perichondrium growth. - Appositional: new chondrocytes and new matrix at the periphery - Interstitial: chondrocytes within tissues divide and add more matrix between the cells - Connective tissue **Extracellular matrix:** - Bone: collagen and minerals - Cartilage: collagen and proteoglycans - Tendons and ligaments: collagen **Bone matrix:** - Organic: collagen and proteoglycans - Inorganic: hydroxyapatite - bendable when mineral removed - brittle when collagen removed **Bone tissue:** - osseous tissue - cells called osteocytes - the hardest of connective tissue - contains calcium makes bone hard and strong - minerals deposited around protein fibers **Bone cells:** - **osteoblasts**: form and help mineralize organic matter of matrix - **osteocytes:** osteoblast that are trapped in the matrix that they formed, in lacunae (spaces occupied by osteocyte cell body) connected by gap junctions inside canaliculi. Mature bone cells, surrounded by matrix, can make small amounts of matrix to maintain it. - **Osteoclast:** resorption of bone, release enzymes that digest the bone, - **Mesenchyme:** become chondroblast or osteoblast **Skeleton:** - **Axial:** vertebral column, rib cage, pairs of ribs, sternum, skull - **Appendicular:** pectoral girdles, the upper limbs, the pelvic girdle, and lower limbs **Classification of bones:** - Long bones - Short bones - Flat bones - Irregular bones **Types of bones tissue:** - **Compact bones:** - **Spongy bones:** **Bone marrow:** - At birth all marrow is red, with age more of it is converted into yellow - **Red marrow:** - **Yellow marrow:** **Structure of long anatomy:** - **Diaphysis:** long shaft, composed of compact bone. Shaft, compact bone surrounding the medullary cavity - **Medullary cavity:** hollow center of diaphysis, has walls composed of spongy bone, filled with yellow bone marrow ad fat - **Epiphysis**: ends, covered by cartilage, thin layer of compact bone overlying sponge bone - End of the bone: spongy bone covered with compact bone - Within joints, covered with hyaline cartilage called articular cartilage - **Articular cartilage:** decreases friction within joints - **Epiphyseal plate:** growth plate - Hyaline cartilage: present until growth stops - **Epiphyseal line:** plate is ossified as bone stops growing in length - **Periosteum:** connective tissue membrane covering the outer surface of a bone, contains blood vessels that nourish the bone - **Epiphyseal disc:** growth plate, site of longitudinal growth, located at each end of diaphysis **Bone development:** - The process of laying down new bone - Osteoblasts form new bone - Osteoclasts break down bone - **Intramembranous ossification:** - **Endochondral ossification:** **Growing bones:** - **Longitudinally:** determines height - Occurs at epiphyseal disc - Cartilage adjacent to epiphysis continues to multiply and grow towards diaphysis - Cartilage is then invaded by osteoblast and become ossified - Bone remodeling: process by which bones grow thicker and wider - Maintains wide and hollow bones that are strong without being too heavy - Continues after longitudinal bone growth has ceased - Certain hormones effect growth - **Laterally:** supports increases in weight - osteoblast form the periosteum - continues after longitudinal growth stops - always being reshaped - accomplished by osteoblast and osteoclast - bone growth is stimulated by exercise **Bone remodeling:** - converts woven bone into lamellar bone - involved in bone growth, changes in bone shape, adjustments in bone due to stress, bone repair, and Ca+ ion regulation **Bone resorption:** - increased in blood calcium - osteoclasts are generally present on the outer layer beneath the periosteum - osteoclast attaches to the osteon which release calcium **Bone strength:** - Increases stress causes bone to increase in strength - Occurs by remodeling, formation of additional bone, alter trabeculae to align with stress - Reduced stress in more osteoclast activity as compared to osteoblast activity **Bone fracture:** - Traumatic and disease - Incomplete (greenstick) and complete **Bone repair:** - Clot forms - Producing network of fibers and cartilage called callus - Osteoblasts enter the callus and form spongy bone - Bone remodeling form spongy to compact **Calcium homeostasis:** - Bone is a major storage site for calcium - Calcium enters the bone when osteoblast (bone deposition) creates new bone - Calcium leaves bone when osteoclasts break down bone (reabsorption) - Stimulation of skeletal muscle contraction - Stimulation of cardiac muscles **Hormones:** - Parathyroid hormone (PTH) - Calcitriol: Increases blood calcium by absorption - calcitonin: lowers blood calcium by inhibiting osteoblast activity **Skeletal terminology:** - body: main part - head: enlarged end - neck: constriction between head and body - margin: edge - angle: bend - ramus: branch off body - condyle: smooth rounded articular surface - facet: small flattened articular surface - process: prominent projection - tubercle: small, rounded bump - tuberosity: knob - trochanter: tuberosity on proximal femur - epicondyle: above condyle - lingula: flat shaped process - hamulus: hook shaped process - horn: horn shaped process - line: low ridge - crest: prominent ridge - spine: very high ridge - foramen: hole - canal: tunnel - fissure: cleft - sinus: cavity - fossa: general term for depression - notch: depression in bone margin - fovea: little pit - groove: deeper narrow depression **Axial skeleton:** - canal axis of the body - protects the brain, spinal cord, and vital organs of the thorax - skull, hyoid bone, vertebral column, and thoracic cage **Skull:** - cranial cavity: occupied by brain - sagittal suture: between parietal bones - coronal suture: between the formal and two parietal bones - lambdoid: between parietal and occipital **Vertebral column:** - supports weight of head and trunk - protects the spinal cord - allows spinal nerves - provides site for muscle attachment - atlas: first cervical vertebra - axis: second cervical vertebra Thoracic cage: - protects vital organs, forms chamber for respiration - ribs (12 pairs) - false ribs: do not attach directly to sternum - true ribs: attach to sternum **classes of joints:** - **fibrous:** - **cartilaginous** - **synovial** - **synarthrosis:** non movable - **amphiarthrosis:** slightly movable - **diarthrosis:** freely movable **Types of movement:** - flexion - extension - abduction - adduction - rotation - circumduction - pronation - supination - excursion - inversion - eversion - combination movements - depression - elevation - excursion - opposition - reposition - inversion **Functions of muscular system:** - movement - maintain posture - respiration - production of heat - communication - heat beat - contraction of organs and vessels **Types of muscle tissue:** - **skeletal** - **smooth** \- walls of hallow organs, blood vessels, eye, glands, skin \- mix food in digestive tract, regulating blood flow \- In some locations autorhythmic \- Controlled involuntary by endocrine and autonomic nervous system \- Gap junctions join smooth cells together \- single central nucleus - **cardiac** **Properties of muscle tissue:** - **contractility:** muscle shorten with force - **excitability:** muscle to respond to stimulus - **extensibility:** can be stretched beyond normal range and be able to contract - **elasticity:** recoil to original resting length after stretched **Nerves and blood vessels:** - **motor neurons:** stimulate skeletal muscle contraction - each motor neuron controls several muscle fibers - veins extend with a nerve through the CT layers **Muscle fiber:** - develops from fusion of myoblast, resulting in muscle cells - \- have a striated appearance - Number of fibers remains constant - **Hypertrophy**: increase in muscle size - **Atrophy:** decrease in muscle size - The greater muscle fiber diameter, the greater force the muscle fiber can generate - Can form more cross-bridges which provides more force of contraction **Structure of a muscle:** - **Layers:** - Muscle - Fascicle - Muscle fiber - Myofibril: bundles of protein filaments, contain myofilaments that cause contraction - Myofilaments: **Sarcomere:** - Basic functional unit of muscle fiber, can contract - **Z disk:** attachment for actin - **I band:** contain Z disc and extend to end of myosin have only actin - **A band:** central region, actin, and myosin - **H zone:** region in A band with only myosin - **M line:** middle of H zone - **Titin:** elastic chain of amino acid, makes muscles elastic **Actin:** - Two strands form double helix extending length of the myofilaments, attached at the end of the sarcomere - Composed of G actin monomers that has active site - Active site can bind to myosin during muscle contraction - Tropomyosin: protein - Troponin: can bind to actin, binds to tropomyosin, binds to calcium - Regulate the interaction between active sites and myosin **Myosin:** - Shape like golf clubs - Has myosin heavy chains that bind and form rod portion and myosin heads - **Myosin head:** can bind to active sites on actin and form cross-bridges, attached to the rod portion can bend and straighten during contraction - ATP enzyme breaks down ATO and release energy, part of that energy is used by myosin to bend during contraction **Histology of structures that can transmit electrical signals:** - Sarcolemma: plasma membrane, surrounds sarcoplasm - Transverse tubules: T tubules, folds of sarcolemma - Sarcoplasmic reticulum SER: stores calcium **Neuromuscular junction structure:** - **Action potentials:** motor neurons carry electrical signals which stimulate muscle fiber action potentials followed by muscle contraction - **Neuromuscular junction (synapse):** points of contract between motor neuron and muscle fiber - **Presynaptic terminal**: axon terminal with synaptic vesicles containing the neurotransmitter acetylcholine (Ach) - Neurotransmitters bind to ligand-gated ion channels on another cell - **Synaptic cleft:** space between - Postsynaptic membrane or motor endplate - Multiple motor-unit recruitment: strength of contraction depends upon recruitment of motor units. A muscle has many motors units **Sliding filament model:** - Actin myofilaments sliding over myosin to shorten sarcomeres - Actin and myosin do not change length - Shortening sarcomeres responsible for skeletal muscle contraction - During relaxation, sarcomeres lengthen because of some external force - H zone is visible - Disks are brought closer together and the sarcomere begins to shorten - A band do not narrow because the length of the myosin myofilaments does not change - The end of the actin myofilaments overlaps **Skeletal muscle fiber physiology:** - Nervous system controls muscle contractions through action potentials **Resting membrane potentials** - Membrane voltage difference across membrane (polarized) - Inside cell more negative due to accumulation of large molecules. More K+ on inside than outside. K+ lacks out not completely because negative proteins hold some back - Outside cell more positive and more Na+ on outside than inside - Na+/K+ pump maintain this situation - Most exist for action potential to occur **Membrane permeabilities:** - Phospholipids bilayer: hydrophobic, and inhibit the movement of charged particles, ion movements is the basis for the electrical properties - Transport proteins have properties of resting and stimulated cell **Ion channels:** - **Ligand-gated:** molecules that bind to receptors, glycoprotein with a receptor site, neurotransmitters - **Voltage-gated:** open and close in response to small voltage changes across plasma membrane **Action potentials:** - **Depolarization:** inside cell becomes less negative, if reaches threshold, depolarization occurs - **Repolarization:** return to resting membrane potential **Excitation-contraction coupling:** - Links electrical and mechanical components of contraction - Action potential produced on sarcolemma - Propagated into T tubules - Calcium channels on SR terminal cisternae open - Calcium enters sarcoplasm, binds troponin - Muscle contraction **Cross-bridge movement:** - The myosin head stores energy from ATP breakdown - The myosin head will remain in the high-energy position until the muscle fiber is stimulated by motor neuron - Initiation of excitation-contraction coupling - **Cross-bridge movement:** Ca binds to the troponin and active sites on the G actin are exposed, the myosin head binds to them - **Power stroke:** rapid movement of the myosin head toward H zone of the sarcomere - Myosin myofilament doesn't move it is actin that moves - **Recovery stroke:** The myosin head breaks down ATP into ADP and P which remain attached to the myosin heads. It returns to its original position. **Muscle relaxation:** - The sodium-potassium pump must actively transport Na+ out of the muscle fiber and K+ into the muscle fiber to return and to maintain resting membrane potential - ATP is required to detach the myosin heads from the active sites from the recovery stroke - ATP is needed for the active transport of Ca+ into the SER **Muscle twitch:** - The response of muscle fiber to a single action potential along its motor neuron - Phases: - Isometric: no change in length but tension increases - Isotonic: change in length but tension constant **Motor unit:** - A single motor neuron and all the muscle fibers activated by it. - Large muscles have motor units with many muscles' fibers **Force contraction:** - Weak and strong - Graded fashion, depending on the force generated by individual muscle fiber - Increasing the number of cross-bridges allows a fiber to contract with more force - Factors that can increase the number of cross-bridges: **Recruitment:** - **Sub-threshold stimulus:** no action potential, no contraction - **Threshold stimulus:** action potential, contraction **Muscle fiber types:** - **Slow twitch:** \- contract more slowly \- smaller in diameter \- better blood supply \- more fatigue resistant than fast twitch \- Large amount of myoglobin - **Fast-twitch:** **Energy sources:** - ATP is required to break the cross-bridge formed between actin and myosin head - ATP provides immediate energy for muscle contraction - Conversion of two ADP to one ATP - Transfer of phosphate from creatine kinease to ADP to ATP - Anaerobic respiration: no oxygen, results in breakdown of glucose to ATP and lactic acid - Aerobic respiration: needs oxygen, breaks down glucose to produce ATP, carbon dioxide and water, more efficient than anaerobic **Muscle fatigue:** - Decreased capacity to work and reduced efficiently of performance - Oxidative stress - Decreased ATP production Smooth muscle: - Not striated, fibers smaller than in skeletal - Spindle shaped - Single central nucleus - More actin than myosin - No Z disks **Cardiac muscle:** - Found only in heart - Straited and branched - Each cell has one nucleus - Has intercalated disks and gap junction - Autorhythmic cells - Action potential for longer refract period **Muscle terminology:** - Origin: muscle end attached to more fixed part of skeleton - Insertion: muscle end attached to more movable part of skeleton - Belly: largest portion of muscle between origin and insertion - Tendons: attach muscles to bones - Agonist: muscle that contracts and cause action, relaxes - Antagonist: opposite to agonist - Synergist: muscles that work together to cause movement, assist prime movement - Prime mover: plays major role in movement - Fixators: stabilization joints crossed by the prime mover **Responses of the whole muscle:** - Fibers are maximally to impulse or not at all (all or nothing), never partially contacts - Whole muscle is capable to contracting partially - The greatest muscle force is achieved by using additional fibers which is recruitment. **Muscle names:** - Location - Size - Shape - Orientation - Origin - Number of heads - Function **Levers:** - **Class I:** "seesaw", head movement, located between the weight and pull - **Class II: "**wheelbarrow", between pull and force, standing on toes - **Class III:** "shoveling", between pull and force, biceps brachii **Muscle tone:** - Continuous state of partial muscle contraction - Tone is due to contraction of different groups of muscle fibers within whole muscle - One group relax, other contacts