Bio 252 exam 3 Questions and Correct Solutions Graded A+

Bio 252 exam 3 Questions and Correct Solutions Graded A+ Parts of ECM - Answer: protein fibers (along with elastic fibers and reticular fibers) GAG help retain water in skin proteoglycans trap salts and ions glycoproteins help attach cells to ECM collagen fibers - Answer: provide resistance to longitudinal tensile/pulling forces. compression or torsion fibroblasts - Answer: produce ECM- protein fibers and ground substance. most common cells found in connective tissue loose connective tissue - Answer: connective tissue proper Primarily ground substance, fibroblasts. support and provide sources of oxygen and blood. dense connective tissue - Answer: connective tissue proper ECM and protein fibers (collagen and or elastic), fibrous tissue, strong and allows the tissue to resist tension dense irregular tissue - Answer: connective tissue proper, dense connective tissue unorganized arrangement of collagen fibers (3D) dense regular connective tissue - Answer: connective tissue proper, dense connective tissue parallel arrangement of collagen fibers (1D), ligaments dense regular elastic connective tissue - Answer: connective tissue proper, dense connective tissue parallel elastic fibers with randomly placed collagen. adipose tissue - Answer: connective tissue proper fibroblasts and ECM present, but primarily adipocytes. Insulation, warmth, shock absorption, protection, and energy reserve. white fat: energy storage brown fat: energy burning (brown from mitochondria), heat generation by 4CP1 (disrupts H+ gradient)- high in babies to regulate body temperature. cartilage - Answer: tough flexible tissue found between joints in bones, the ear, nose, and respiratory passages. Absorbs shock and resistance to force. consists of ECM and cells. Generally avascular (no blood). O2 diffusion. chondroblasts - Answer: immature, rapidly divide, and generate ECM. chondrocytes - Answer: mature and inactive. Produce ECM hyaline cartilage - Answer: most abundant, mostly ground substance and fine collagen bundles. Found at end of bones that forms joints. fibrocartilage - Answer: Predominantly collagen bundles and fibroblasts, chondrocytes and chondroblasts. Involved in distributing forces between two bones in a joint. elastic cartilage - Answer: Primarily made of elastic fibers. Give vibration for hearing. blood - Answer: platelets (blood clotting), red blood cells (oxygen carrying), and white blood cells bone - Answer: protection. mineral storage, acid-base homeostasis, blood cell formation (red marrow), fat storage (yellow marrow), movement, support. 65% hydroxyapatite crystals (inorganic matrix)- source of calcium to give strength and rigidity. 35% collage and osteoid (ground substance)- bring in water to resist compression bone supplements for dogs: cosequin (proteoglycan), nutritional supplements don't do much in research. Organic and inorganic matrices - Answer: work together to promote bone strength and function remove organic: bone becomes brittle and shatters remove inorganic: bone can't resist compression, becomes flexible osteocyte - Answer: maintains bone tissue, main cells osteoblast - Answer: bone builders, form bone matrix osteogenic cell - Answer: stem cell that differentiate into osteoblasts. osteoclast - Answer: bone breakers, reabsorb bone osteoblasts and osteocytes - Answer: 1. osteogenic cells differentiate into osteoblasts 2. osteoblasts deposit bone until they are trapped and become osteocytes 3. osteocytes maintain the bone ECM Osteocyte cont. - Answer: mature bone cells that are amniotic, derived from osteoblasts. Though to be mechanosensory cells that control activity of osteoblasts and osteoclasts. Communicate with other osteocytes via gap junctions osteoclasts cont. - Answer: bone breakers and border of bone. secrete enzymes and H+ to break down bone and take up ions. Periosteum - Answer: dense irregular connective tissue that surrounds bone (vascular) perforating fibers - Answer: penetrate bone and secure periosteum endosteum - Answer: thinner connective tissue within the bone diaphysis - Answer: shaft of long bone epiphysis - Answer: enlarged rounded ends of long bone articular cartilage - Answer: can be both hyaline cartilage and fibrocartilage; reduces friction medullary cavity - Answer: hollow cavity within diaphysis of long bone that houses marrow epiphyseal plate - Answer: line of hyaline cartilage from which long bones grow in length how does blood get into bone tissue? - Answer: 1. periosteum supplies the compact bone 2. nutrient foramen: small hole in diaphysis where nutrient arteries enter the medullary cavity. bone marrow - Answer: yellow marrow: blood vessels and adipocytes red marrow: reticular fibers (web-like structures) that support hematopoietic cells. osteon - Answer: compact bone cylindrical "tree trunk like" structure that contain ECM and osteocytes connected by caliculi lumallae - Answer: compact bone layers of compact matrix. Tree "rings"- provide strength due to collagen fiber in differing directions central cavity - Answer: compact bone haversian canal: passage where blood vessels that supply the bone are present. lacunae - Answer: compact bone small cavities where osteocytes reside. Filled with ECF and located between lamellae. 1 in 1. Canaliculi - Answer: compact bone canals of the bone tissue that connect lacunae. Osteocyte processes extend through to communicate with one another via gap junctions. interstitial lamellae - Answer: compact bone lamellae between osteons. Remnants of resorbed osteons circumferential lamellae - Answer: compact bone deep to periosteum and superficial to spongy bone that provide strength and tension. spongy bone - Answer: non-weight bearing component of bone. protects bone marrow traberculae - Answer: structures covered with endosteum and devoid of osteons. concentric lamellae present blood supply from bone marrow osteogenesis - Answer: ossification process of bone formation. Starts during embryonic development and is complete by age 7 intramembranous: built one "model" that is made of embryonic connective tissue endochondral: built on "model" made out of hyaline cartilage. primary bone - Answer: organic matrix and osteocytes, minimal inorganic matrix. irregular collagen bundles, embryonic bone, bone after break. secondary bone - Answer: Primary bone resorbed by osteocytes and replaced by mature bone. Fully formed lamellae with regularly arranged collagen. Stronger than primary bone. high % of inorganic matrix. mesenchymal cells - Answer: key, are model become myocyte, adipocyte, osteoblast, neuron, chondrocyte ossification - Answer: process of laying down new bone material. Requirements are cells (chondrocytes, osteoblasts), calcium, and blood supply. calcification - Answer: process by which calcium salts build up in soft tissue, causing it to harden intramembranous ossification - Answer: flat bones (skull, clavicle), primary bone formation, spongy bone forms first in primary ossification. 1. osteoblasts develop in the primary ossification from mesenchymal cells 2. osteoblasts secrete organic matrix, which calcifies and trapped osteoblasts become osteocytes 3. osteoblasts lay down trabeculae of early spongy bone, and some of the surrounding mesenchyme differentiates into periosteum. (become vascularized) 4. osteoblasts in periosteum lay down early compact bone Often soft and takes a while to connect: kid skull bones aren't connected. endochondral ossification - Answer: bones inferior to head. Typically starts during fetal period and continues to age 7. Derived from hyaline cartilage. Begins in primary ossification center. Long bone has secondary ossification center within epiphysis. 1. chondroblasts in perichondrium differentiate into osteoblasts 2a. osteoblasts build the bone collar on the bone's external surface as the bone begins to ossify from outside. 2b. simultaneously, the internal cartilage begins to calcify and chondrocytes die 3. in the primary ossification center, osteoblasts replace the calcified cartilage with early spongy bone; the secondary ossification centers and medullary cavity develop. 4. As medullary cavity enlarges, the remaining cartilage is replaced by bone; the epiphysis finish ossifying growth plate - Answer: metaphysis: neck portion of long bone between the diaphysis and epiphysis that contains the growth plate. longitudinal bone growth - Answer: process by which log bones lengthen. chondrocytes play a key role. Occurs within epiphyseal plate (5 zones). Typically occurs between ages 12-15. epiphyseal plate growth - Answer: cartilage that remains epiphyseal plate layers: zone of reserve cartilage, zone of proliferation, zone of hypertrophy and maturation, zone of calcification, zone of ossification zone of reserve cartilage - Answer: typical hyaline cartilage farthest from marrow cavity; shows no sign of transforming into bone. Doesn't transform, but can if needed. zone of proliferation - Answer: chondrocytes divide zone of hypertrophy and maturation - Answer: chondrocytes enlarge, mature, and stop dividing zone of calcification - Answer: chondrocytes die (far from blood) and ECM calcifies zone of ossification - Answer: osteoblasts invade calcified cartilage and lay down bone bone is resorbed by osteoclasts and replaces by secondary bone. growth plate injuries - Answer: many orthopedic surgeons try to avoid surgeries that would cause manipulation of growth plate until it is completely closed (18-21 years) terminate bone growth (bones different length) curvatures: part of growth plate is still active, while other part is not. growth hormone - Answer: induces longitudinal bone growth. chondrocytes: endochondral ossification, linear growth osteoblast and osteoclasts: bone turnover increases, bone mineral density increases testosteron and estrogen - Answer: promote bone growth appositional bone growth - growth width (testosterone) increases rat of mitosis at epiphyseal plate. Can increase closure of epiphyseal plate (estrogen is more potent than testosterone). Prohibit activity of osteoclasts. why does bone remodeling occur? - Answer: Bone is deposited if you have a lot of activity, pressure, or tension of bone: increased osteoblast activity. when we have adequate diet, estrogen levels increase: decrease osteoclast activity. Bone is broken down when you have a sedentary life style or lack a nutritional diet or have continuous pressure on bone. bone deposition - Answer: osteoblasts in periosteum and endosteum. Formation of organic matrix and facilitate inorganic matrix. proteoglycans and glycoproteins that trap Ca2+, which crystallize and calcify. Secrete vesicles containing Ca2+, ATP, and enzymes that bind to collagen fibers. bone resorption - Answer: mediated by osteoclasts acidic environment brakes down hydroxyapatite crystals in inorganic matrix. enzymes catalyze breakdown of proteoglycans, GAGs, and glycoproteins rheumatoid arthritis - Answer: heavy load towards resorption. TNF2 upregulated and inhibits deposition. stress placed on bones - Answer: support bone remodeling compression: force between body's weight and the ground. athletes tension: stretching force. orthodontist hormones - Answer: support bone remodeling testosterone: bone deposition estrogen: inhibits osteoclast activity nutrition - Answer: calcium: parathyroid hormone increases Ca2+ release into blood stream. vitamin D: promotes Ca2+ uptake in intestines vitamin K: glycoprotein production (bind Ca2+) protein: collagen synthesis vitamin C: promotes the synthesis of collagen simple fracture - Answer: skin and tissue not damaged compound fracture - Answer: damage of surrounding tissue repair - Answer: 1. a hematoma fills the gap between the bone fragments (restrict blood supply) 2. fibroblasts and chondroblasts infiltrate the hematoma and a soft callus forms 3. osteoblasts build bone callus (primary bone), bridge, penetrates out 4. the bone callus is remodeled and primary bone is replaces with secondary bone . Callus lump will remain. men and women with sedentary life style had more risk of bone fracture. Suggest higher importance of exercise in women. (estrogen?) properties of muscle cells - Answer: 1. contractility: ability to contract (not shorten) 2. Excitability: response to stimuli 3. conductivity: electrical changes across membrane 4. distensibility: stretch without damage 5. elasticity: stretch and retain shape skeletal muscle - Answer: multiple nuclei, striated long and cylindrical, mostly attached to skeleton. Voluntary movement. Body movement. individual cell: muscle cell fiber cardiac muscle - Answer: striated, single nucleus, branched, have intercalated discs (gap junctions allow them to talk). Found in heart and involuntary. Beating heart. smooth muscle - Answer: smooth, not striated, single nucleus, interact via gap junctions. Found in wall of hollow organs/skin/eyes and involuntary. endomysium - Answer: ECM surrounding each muscle cell fibers fascicle - Answer: multiple cell bundles together perimysium - Answer: connective tissue sheath surrounding fascicle epimysium - Answer: connective tissue sheath surrounding all fascicles muscle fascia - Answer: separates individual muscles from each other tendon - Answer: connect to muscle bone skeletal muscle function - Answer: muscle tension: contraction to generate force. action: production of body movement heat production: ATP-movement (heat) functional groups of skeletal muscles - Answer: agonist: most force required for a given movement. antagonist: opposite of agonist to oppose and slow action synergist: muscles that work with agonists to guide movement and stabilize joint fixator: hold bone in place to make movement efficient 2 tendons of each muscle - Answer: origin: muscle piece attached to bone and almost fixed insertion: muscle attachment to the bone that moves muscle movement - Answer: in a leverl system: lever, load to move, force applied, fulcrum ( hinge that allows it to move) mechanical advantage: closer fulcrum to the load, less force needed mechanical disadvantage: further fulcrum from load, more force needed first class lever - Answer: fulcrum in middle, load on one side and force on other. On posterior of neck, see-saw. second class lever - Answer: fulcrum on one side and load on other. Force applied on opposite side of lever from load. metatarsophalangeal joints, like a dolley third class lever - Answer: load and fulcrum on opposite ends with force applied in middle. Bicep curls, tongs sarcolemma - Answer: skeletal muscle fiber plasma membrane of muscle fiber (voltage gated Na+ and K+) myofibril - Answer: skeletal muscle fiber proteins involved in cell contraction, myofilaments sarcoplasmic reticulum - Answer: skeletal muscle fiber smooth endoplasmic reticulum that stores and releases Ca2+ Transverse tubules (T-tubules) - Answer: skeletal muscle fiber inward extensions of sarcolemma that form a tunnel-like network and filled with extracellular fluid. terminal cisternae - Answer: skeletal muscle fiber enlarged portions of the sarcoplasmic reticulum on either side of T-tubules thick myofilaments - Answer: myosin protein in clusters: contractile head: where thin filaments bind ATP dependent thin myofilaments - Answer: actin: subunits of contractile protein with active site that binds myosin. tropomyosin: ropelike protein that spirals around actin and covers active site at rest troponin: holds tropomyosin in place (moves in response to Ca2+) elastic myofilaments - Answer: titin: thinnest filament shaped like a slinky. holds thick filaments in place resist excessive stretching and provide elasticity myofilament sacromere - Answer: I-bands: toward outside, repeating structures of thin filaments and elastic . Z-discs: help anchor thin filaments in place and borders structural unit. I-band is lightest color because it's only thin filaments. A-band: middle dark band. At borders, there are zones of overlap between thick and thin filaments H-band: middle of A-band, slightly lighter color, only has myosin. M-line: dark line of structural proteins that keep it in place. Middle of H-zone sliding filament theory - Answer: Actin has myosin binding sites, myosin binds onto actin and pulls it in to contract. 1. upon stimulation, myosin head binds to actin and sliding begins. 2. Thin filaments slide past thick ones. 3. z-discs closer together, I-bands shorter, H-band smaller. A-band same size. we have many sacromeres in one myofibril, when all sacromeres shorten, so does myofibril. We have many myofibrils in one muscle fiber, when all myofibrils shorten, so does the muscle cell. maximal contraction - Answer: optimal actin and myosin overlap will produce maximal contraction. contraction regulation - Answer: in a resting state, tropomyosin prevents myosin from binding t actin. Skeletal muscle is innervated by motor neurons. Acetylcholine is major neurotransmitter that signals to skeletal muscles. Acetylcholinesterase (AChE) is found in synaptic cleft. Motor end plate is region of sarcolemma that has "folded structure" that contains nicotinic cholinergic receptors. Action potential in skeletal muscle - Answer: 1. AP arrives at axon terminal and triggers Ca2+ channels in axon terminal to open 2. Ca2+ entry triggers exocytosis of synaptic vesicles 3. synaptic vesicles release ACh into synaptic cleft 4. ACh binds to ligand-gated ion channels in the motor end plate 5. ion channels open and Na+ enter the muscle fiber 6. Entry of Na+ depolarizes the sacrolemma locally, producing and end-plate potential. Neural signals stimulate release of calcium from SR to sarcoplasm. Na+ can enter cell. 7. end-pate potential stimulate an AP 8. AP propagated down teh T-tubules 9. T-tubule depolarization leads to openiing of Ca2+ channels in AR and Ca2+ enter the cytosol. calcium binds to troponin, leading to release of tropomyosin from myosin-binding sites. myosin binding in contraction - Answer: 1. ATP hydrolyzes and "cocks" the myosin head 2. myosin head binds to actin 3. the power stroke occurs when the phosphate detaches from the myosin head and myosin pulls actin toward the center of the sacromere. ADP leaves the myosin head at the end of the power stroke. 4. ATP breaks the attachment of myosin to actin. Cross-bridge cycle is repeated to contract the sacromere. muscle relaxation - Answer: 1. AChE degrades remaining ACh, and the final repolarization begins. 2. sarcolemma returns to resting membrane potential (-90 mV) and Ca2+ channels in SR close. 3. Ca2+ are pumped back into SR, returning Ca2+ concentration in cytosol to it's resting level. 4. troponin and tropomyosin block the active sites of actin and muscle relaxes muscle spasm - Answer: a muscle that is unable to relax. rigor mortis: when muscles can't relax after death. (Ca2+ remains in cytosol and stimulate contraction) Ca2+ and AChE work continuously to allow for muscle contraction. Muscle cells need a lot oATP - Answer: Na+/K+ ATPase that maintains resting membrane potential (-90 mV) pf sarcolemma. muscle contraction: cross-bridge cycle and actin/myosin reactions muscle relaxation: active transport of Ca2+ back into SR muscle cells don't store high amounts of ATP cretine kinase - Answer: immediate energy creatine phosphate abundant in muscle fibers give phosphate group to ADP. Creating creatine and ATP. Creatine kinase is enzyme for this. This reaction is also bidirectional. glycolytic catabolism - Answer: immediate energy glycolysis: 1 glucose=2 ATP gluose source: glucose from blood stream, glycogen stores in muscle cells. Oxygen dependent: aerobic: 2 pyruvate enter mitochondria and citric acid cycle Oxygen independent: anaerobic: 2 pyruvate converted to 2 lactate. Cori cycle: converting lactate into glucose (gluconeogenesis in liver) oxidative respiration (catabolism) - Answer: long-term energy oxygen dependent mechanism that produces 32-38 ATP. 1. glycolysis (2 n3t ATP)- cytosol 2. pyrivate oxidation and citric acid cycle (2 net ATP)- mitochondria 3. oxidative phosphorylation (28-34 ATP)- mitochondria oxygen dependence: O2 non-polar, diffuses into muscle cell from blood stream. myoglobin- O2 carrying protein found in cytosol of muscle cells. Releases O2 to be used in mitochondria for oxidative catabolism. muscle twitch - Answer: laboratory generated phenomenon where a muscle fiber responds to a single AP from a motor neuron. 1. latent period: AP spreads through sarcolemma 2. contraction period: tension rapidly increases during cross-bridge cycling. 3. relaxation period: tension decreases as C2+ are pumped back into SR. refractory period after AP is very short in muscles, can have repeated stimulation. wave summation - Answer: amount of tension produced depends on frequency of stimulation.. unfused tetanus: muscle fiber is not allowed to relax completely between stimuli: fiber stimulated about 50 times per second. fused tetanus: muscle fiber is not allowed to relax between stimuli. Fiber stimulated 80-100 times per second, which generates sustained contraction and maximal tension. increasing stimuli frequency= increasing tension New stimulus starts before Ca2+ is returned to SR Fused tetanus will lead to muscle fatigue length-tension relationship - Answer: sarcomere A: overly shortened- 85% of maximal tension (too much overlap= no room for movement) sarcomere B: optimal length- near 100% maximal tension Sarcomere C: overly stretched- 90% maximal tension (too little overlap= too hard for myosin to grip actin) twitch fibers - Answer: myosin ATPase: regulates how quickly a muscle fiber proceeds through a twitch contraction. fast twitch fiber: high myosin ATPase activity found in muscles that move body parts quickly. slow twitch fiber: low myosin ATPase activity found in muscles that require slow and sustained contractions. twitch fiber speed regulation - Answer: Type I fibers: slow-twitch fibers that are small in diameter. maintain extended contraction, which requires high ATP levels via oxidative catabolism (high myoglobin) Type II fibers: large diameter and contract rapidly, but fatigue quickly. Rely on glycolytic energy sources, have less myoglobin. IIa: oxidative and glycolytic, intermediate mitochondria and myoglobin IIx: glycolytic, low mitochondria and myoglobin. High ATPase The motor unit - Answer: motor neuron with cluster of muscle fibers average size: 150 muscle fibers, but varies based on function fine control: multiple small motor units large and powerful muscles: muscle fibers/motor unit each motor unit consists of a single class of fiers recruitment - Answer: the greater the force (tension) needed, the greater he motor units that are activated Slow motor units are activated first (type I), followed by fast motor units (type 2) if additional force is needed muscle tone - Answer: involuntary activation of motor units to generate a small amount of tension of a muscle at rest (posture). hypotonia: low skeletal muscle tone hypertonia: abnormally high muscle tone isotonic contraction - Answer: enough tension is generated to move a load and the level of tension is consistent throughout the contraction. Tension stays the same, but muscle changes length (bicep curl) isotonic concentric contraction: muscle tissue shortens. Force generated by muscle is greater than external load. Lifting weight isotonic eccentric contraction: muscle tissue lengthens, force generated by muscle is less than the load. Putting down weight. Elastic filaments (sarcomeres) stretch, although motor units are generating tension. Generate the greatest amount of tension. isometric contraction - Answer: external load is equal to the force generated by the muscle. Muscle remains same length, tension varies. Length of muscle doesn't change. Holding out a weight. elastic components of muscle organ - Answer: tendons, connective tissues between fibers, elastic molecules in cytoplasm. These elongate in isometric contraction to maintain length. principle of myoplasticity - Answer: muscle will alter its structure to support its function. endurance training: more repetitions, lighter load (swimming and running). Increased oxidative enzymes, increased # of mitochondria and mitochondrial proteins, increases # of blood vessels. Constant supply of ATP. Resistance training: fewer repetitions, higher load (strength training). increases # of myofibrils, increase diameter of muscle fiber and myofibrils. Decreased portion of mitochondria. hypertrophy: enlargement of an organ, tissue or cell. sedentary lifestyle: physical inactivity. Decreased oxidative enzymes, decreased # of myofibrils and decreased diameter of muscle fiber. atrophy: a decrease in the size of a cell or organ muscle fatigue - Answer: inability to maintain a level of intensity during exercise. depletion of metabolites (glycogen, blood glucose, creatine phosphate) reduced O2 supply to muscle fibers (reduced O2 bound to myoglobin) accumulation of Ca2+, ADP, PO4- environment: high heat, high altitude out of balance homeostasis when we workout - Answer: elevated body temp.: energy is lost during glycolysis and oxidative metabolism, raising body temp. ion concentrations are abnormal: abnormal Na+ and Ca2+ in the cytosol and K+ in ECF. correct blood pH: lactic acid and CO2 in blood can reduce blood pH excessive post-exercise oxygen consumption (EPOC) - Answer: when rate of ventilation remains high after workout. Restores homeostatic balance. elevated body temp: sweating, and ATP dependent process, helps us to decrease body temp. (active transport of Na+ out of cells) ion concentrations: Na+/K+ ATPase helps restore ion gradients across a membrane (active transport- require ATP) Blood pH: exhalation of CO2 helps to restore slight alkalinity of blood. chambers of the heart - Answer: 4 chambers: eft atrium, right atrium, left ventricle, right ventricle atrium: receive blood from veins ventricle: pump blood to arteries. pericardium - Answer: membrane surrounding the heart. 1. fibrous pericardium- tough outer layer with collagen bundles. Low distensibility. helps connect heart to the rest of the body. 2. serous pericardium: thin inner layer of serous fluid. Parietal pericardium outer, epicardium inner. Pericardial fluid: thin serous fluid, that acts as a lubricant during heart contractions. the heart wall - Answer: epicardium: thin layer of aveolar (loose) connective tissue with fat droplets. myocardium: thickest layer consisting of cardiac muscle calls (myocytes) and extracellular matrix. endocardium: endothelium simple squamous epithelium and connective tissue. Tissue continues to blood vessels. Cardiac myocytes: major layer in heart wall pulmonary circuit - Answer: 1. deoxygenated blood is pumped to the lungs by the right side of the heart. 2. gas exchange occurs between air in alveoli and blood in the pulmonary capillaries. 3. oxygenated blood is returned to the left side of the heart. systemic circuit - Answer: 1. oxygenated blood is pumped to the body by the left side of the heart goes through aorta. 2. Gas exchange occurs between tissues and blood in systemic capillaries. 3. Deoxygenated blood is returned to the right side of the heart. The great vessels - Answer: superior and inferior vena cava: bring deoxygenated blood back to the heart pulmonary trunk: receives deoxygenated blood from right ventricle slits into pulmonary arteries that carries deoxygenated blood to the veins. pulmonary veins: oxygenated blood returns to the heart (left atrium) aorta supplies systemic circuit with oxygenated blood Atria - Answer: asymmetrical: right is larger and thinner; left is thicker and smaller. left is thicker to provide pressure to push blood further in body. uricle: muscular pouch that expands to allow for more blood interatrial septum: separated left and right atria foramen avale: hole in fetal heart that allows blood flow from right atrium to left ventricles - Answer: asymmetrical: right ventricle is thin; left is thick. papillary muscle: finger like projections that attach to valves between atria and ventricles via chordae tendineae (tendons) interventricular septum: separates left and right ventricle and helps expel blood. heart valves - Answer: blood flows unidirectionally. atria: low pressure and blood flows via gravity and vein pressure. ventricles= high pressure and against gravity Without valves, blood could back flow from ventricles to atria. atroventricular valves - Answer: valves between atria and ventricle (AV valves) inflow valves cusps: flaps of endocardium over fibrous skeleton (dense connective tissue) Tricuspid valve: 3 cusps (right atrium and right ventricle) Bicuspid (mitral) valve: 2 cusps (left atrium and left ventricle) semilunar valves - Answer: valves ventricles and arteries Prevents blood from pulmonary trunk and aorta from reentering ventricles outflow 3 cusps pulmonary valve: right ventricle and pulmonary trunk aortic valve: left ventricle and aorta. ausculation - Answer: listening to heart sounds via a stethoscope "lub": AV valves "dub": semilunar valves coronary circulation - Answer: blood vessels that supply the cardiac tissue. Arteries branch from the aorta. Veins drain into coronary sinus (right atrium) coronary artery disease - Answer: blockage of coronary arteries: low blood flow to myocardium (myocardia ischemia) Myocardial infarction: heart attack. No blood flow through coronary arteries. Plaque rupture/erosion with occlusive thrombus or non-occlusive thrombus. Widow maker: severe case of coronary artery disease in left anterior descending (or interventricular) artery. Treatment for heart attack - Answer: 1. angioplasty and stenting: catheter balloons artery and a stint is placed to keep it open. 2. Coronary artery bypass surgery: graft of vein linked from aorta and routed past blockage. heart disease is leading cause of death for both men and women in the US. Difference between skeletal and cardiac muscle cells - Answer: signal: voluntary; involuntary pacemaker cells: no; yes striated: yes; yes shape: long and cylindrical; shorter and branched nuclei: many; 1-2 myoglobin: yes; yes intercalated discs: no; yes kinds of cells in heart - Answer: 2 kinds autorhythmic cells: pacemaker cells that generate AP. About 1% of the total # of cardiac muscle cells contractile cells: receive AP and send AP to other contractile cells myocytes: similar features to skeletal muscle cells Not as pronounced T-tubules branched ion channels in cardiac tissue - Answer: voltage-gated sodium ion channels: found in all cardiac muscle cells with the exception of certain pacemaker cells calcium ion channels: voltage gated opening, but time dependent (close after a period of time, regardless of voltage) potassium ion channels: ligand gated and voltage gated non-selective cation (HCN) channels: certain pacemaker cells and activated by hyperpolarization. Allows Na+ to enter and K+ to exit simultaneously. Pacemaker potential - Answer: 1. slow initial depolarization phase: more cations leak in than out through HCN channels in the plasma membrane (causing the membrane to slowly depolarize to the threshold) 2. full depolarization phase: at threshold voltage gated Ca2+ channels open, and Ca2+ enter the cell, causing the membrane to fully depolarize. 3. repolarization phase: Ca2+ channels close and the voltage gated K+ channels open, causing K+ outflow and membrane repolarization 4. minimal potential phase: K+ channels remain open, and the membrane hyperpolarizes. This opens HCN channels, and the cycle repeats. Hyperpolarization at end of stage 4 activates stage 1. cardiac conduction system - Answer: authorhytmic cells fire action potentials via a group of pacemaker cells. 1. sinoatrial node (SA node): right atrium and fastest rate of depolarization that is regulated by the autonomic nervous system. 2. atrioventricular node (AV node): posterior and medial to tricuspid valve, with slower rate of depolarization. 3. Purkinje fiber system: slowest to depolarize. AV bundles, right and left bundle branches, terminal branches. 1. SA node generates AP which spreads to the atria cells and the AV node. 2. After the AV node delay, The AP is conducted to the AV bundle 3. the AP spreads from the bundle branches along the Purkinje fibers to the contractile cells of teh ventricles. intercalated discs - Answer: sinus rhythm: cardiac rhythm associated with depolarization of the SA node discs: feature of myocytes desmosomes: molecular velcro that holds cells together gap junctions: ion transport gap junctions promote cell-cell communication. authorhythmic cell- contractile cell- contractile cell contractile cell AP - Answer: 1. rapid depolarization phase: voltage gated Na+ ion channels activate and Na+ enter rapidly depolarizing the membrane 2. initial repolarization phase: Na+ channels are inactivated and some K+ channels open; K+ leaks out, causing a small initial repolarization 3. plateau phase: Ca+ channels open and Ca+ enters as K+ exits prolonging depolarization 4. Repolarization phase: Na+ and Ca2+ channels close as K+ continue to exit, causing repolarization. Effective refractory period (ERP): forceful contractions and refill chambers with blood plateau phase - Answer: allows for Ca2+ to enter cell: excitation-contraction coupling extends duration of AP ERP lasts throughout plateau period close at peak and don't reopen until go below threshold. No new contraction until the muscle completes contraction and relaxation. Fused tetanus doesn't work in cardiac muscle. Absolute refractory period throughout plateau, a long absolute refractory period prevents tetanus and we need the muscle to relax for a "refill" ECG (electrocardiogram) - Answer: graphical depiction of electrical activity of cardiac muscle cells over a period of time. P-wave: initial, small wave that represents depolarization of atrium (not SA node) ORS complex: ventricular depolarization t-wave: ventricular repolarization R-R interval: time between 2 successful waves and represents entire AP. P-R interval: depolarization of SA node to spread through cardiac tissue S-T segment: plateau phase of ventricular AP O-T interval: ventricle AP hear problems - Answer: arrthmia: abnormal heart rate tachycardia: elevated heart rate (above 100 bpm) bradycardia: low heart rate (below 60 bpm) myocardial infarction: ischemia: not enough blood to heart abnormal wave: ventricles can't get what it needs: ST hump fibrillation: unregulated retrial activity in the heart afib: atricular fibrillation, more tall peaks vfib: ventricular fibrillation, less tall peaks aystole: flatlining: no electrical activity CPR to address myocardial infarction - Answer: ischemia: not enough blood to heart blood functions - Answer: gas exchange- O2 in, CO2 out distribute solutes: nutrients, ions, hormones, waste immune function body temp.: distributes heat that is given by metabolism clotting/sound healing acid-base homeostasis blood pressure: volume of blood blood is made of - Answer: we have 5 liters (8% of body weight) connective tissue liquid plasma (55%) and formed elements (cells) Cells: myocyte, lymphocyte, neutrophil, eosinophil, basophil, macrophage, erythrocyte, platelets plasma: water, albumin: large proteins and regulates water/retention, immune protein: antibodies, transport proteins: help with movement of fats and steroid (lipoproteins), clotting proteins: stop bleeding and wound healing. erthrocytes - Answer: red blood cells: Large surface are to volume ratio- gas exchange. Mature cells are anuclear- no metabolism or synthesis cytoplasm consists of enzymes and hemoglobin (hb) Hemoglobin - Answer: four polypeptides: 2 alpha and 2 beta- bound by heme group heme binds oxygen- oxyhemoglobin (hbO2). systemic arteries- 100% bound= red, systemic veins- ;ess bound= dark red. Carbamino hemoglobin: hemoglobin bound CO2 Carbon monoxide poisoning: greater affinity for hemoglobin, preventing O2 Erythropoiesis - Answer: creation of erythrocytes: 5-7 days 1. hematopoietic stem cell: call may become any type of formed element 2. erythrocyte-CFU: cell is now committed to become an erythrocyte 3. proerythroblast: step requires the hormone erythropoietin (from liver) 4. early erythroblast: hemoglobin is synthesized rapidly 5. late erythroblast: nucleus shrinks and is ejected with other organelles 6. reticulocyte: remaining organelles ejected; cell enters bloodstream 7. erythrocyte: cell is now mature regulated by a negative feed back loop. Chemoreceptors when O2 is low trigger kidney to release erythropoietin. Erythropoietin acts on HSC in bone marrow and can also convert yellow marrow to red marrow. Rate of erythropoiesis happens faster to return blood O2 to normal. Growth factors also regulate erythropoiesis. Death of erythrocytes - Answer: 1. Red blood cells trapped in spleen sinusoids, changes in plasma membrane make it trapped. 2. macrophages in spleen phagocyte red blood cells. 3. hemoglobin broken into amino acids Fe3z= and bilirubin 4a. Fe3+ and amino acids are sent to red marrow for reuse 4b. bilirubin sent to the liver for disposal bilirubin: yellow compound in breakdown of hemoglobin anemia - Answer: decrease oxygen carrying capacity decreased oxygen delivery to tissue fatigue, weakness, pallor, shortness of breath severe cases: elevated heart rate iron deficiency anemia - Answer: cause by blood loss or greater O2 demand. Can also be cause by poor nutrient intake. Red blood cells are less plump and smaller because they have less iron. Also aren't as good at binding O2. Vitamim B6: key vitamin involved in hemoglobin synthesis; iron fro heme hermatocrit anemia - Answer: % of red blood cells in blood. poycythemia: too many red blood cells, anemia: too little red blood cells hermatocrit anemia: erythrocyte destruction. If mom is RH- and fetus is RH+, mom can develop antibodies against erythrocytes. Caused by Rh factors on blood. coombs testing: antibodies already attached to RBCs: direct coombs testing: antibodies in serum: indirect aplastic anemia - Answer: decreased erythropoiesis, can be caused by chemotherapy drugs. sickle cell disease - Answer: abnormal hemoglobin shape. Have hemoglobin that can get stuck. autosomal recessive disorder. cardiac cycle - Answer: all events associated with blood flow through the heart during a single heart beat. blood flow: is driven by pressure changes that are produced as a result of muscle contraction. high to low pressure. Driven by pressure gradients. systole: contraction of heart muscle. diastole: relaxation of heart muscle both atria and ventricles have their own systole and diastole, "lub": longer and louder, ventricle contraction "dub": shorter and softer, ventricle relaxation Start: just before atrial depolarization and contraction starts. depolarization starts at SA node. pressure is a result of systole (contraction) and diastole of cardiac muscle. During diastole the chamber fill with blood and prepare for next cardiac cycle. heart systole and diastole refer to ventricle, as they produce a far greater pressure and force blood to circulate. Total length: 0.8 s Cardiac cycle events - Answer: start 1: late atrial and ventricular diastole (all chambers relaxed). AV valves open, semilunar valves closed. Ventricular filling from atria 2: ventricle filling stage. AV valves open, semilunar valves closed. Ventricle filling from atria- more blood in ventricle than atria. Atrial systole (ventricles still relaxed) 3: isovolumetric contraction phase. Ventricular systole (atrial diastole). AV valves closed (pushed by backflow of blood rom ventricle), semilunar valves closed (internal pressure is generated in ventricles) 4: ventricular ejection phase. Ventricular systole (atrial diastole). AV valves close and semilunar valve open (ventricle pressure rises 120 mmHg). Ventricle pressure exceeds aorta/PT pressure, causing blood to enter aorta/Pt 5: isovolumetric relaxation phase. Early diastole. AV valves closed and semilunar valves closed ( ventricle pressure drops and pressure from aorta/T closed SL valves). Most blood is ejected to aorta/PT, some blood remain in ventricle. Atrial diastole fill with blood from veins. 6: mid-diastole. AV valve open and semilunar valves closed. Pressure of atria exceeds ventricle and AV valves open. Differential pressure changes in right and left ventricle: pressure in right ventricle is less than left ventricle since it only pushes blood to pulmonary circuit and not the rest of the body. heart volumes - Answer: end diastolic volume (EDV): 120 mL, amount of blood in a fully relaxed ventricle. end systolic volume (ESV): 50 mL, amount of blood left in ventricle after contraction stroke volume (SV): amount of blood pumped out by the ventricles during each heart beat: SV=EDV-ESV 120 mL- 50 mL= 70 mL Cardiac output (CO): amount of blood ejected from the ventricles to the aorta/PT in one minute. CO=SV*HR (heart rate in beats per minute) Average resting heart rate is 75 bpm CO=70*75=5250 mL/min, 5.2 L/min entire blood supply passes through body every minute what impacts stroke volume? - Answer: sarcomere strength in ventricles before contraction: preload. High preload= high EDV= high SV (also makes low ESV) Ability to generate tension in absence of external influences: contractility. High contractility= low ESV= high SV Force ventricles overcome to eject blood: after load. low afterload= low ESC= high SV what impacts heart rate? - Answer: in normal conditions, SA node sets heart rate. chronotropic agents: affect the rate of at which the SA fires AP. positive chronotropic agents: sympathetic nervous system, elevated body temp., hormones negative chronotropic agents: parasympathetic nervous system and decreased body temp. heart and autonomic nervous system: sympathetic and parasympathetic nervous systems synapse nodes (SA nodes and AV nodes) hormones tah ipact cardiac output - Answer: adrenal medulla: epinephrine and norepinephrine thyroid hormone: T3 induces cardiac output and ventilation (metabolism) ADH and aldosterone: water retention- elevated cardiac output. cardiac out put base don demand - Answer: resting: CO=SV*HR=70*75= 5 L/min exercise: SV=EDV-ESV=145-30= 115 mL CO= SV*HR= 115*190= 22 L/min cardiac reserve - Answer: difference between max CO and resting CO A well trained endurance athlete may have a reserve of 35 L/min or 600% of normal. increased and decrease CO - Answer: increased: hormones that cause fluid retention from kidney: increase preload= increase SV= increase CO. SNS activity, positive iontropic and chronotropic hormone increase= increased contractility= increased SV= increased CO. increased body temp.= increased heart rate= increased CO. decreased: hormones that decrease fluid retention in kidney: decrease preload= decreased CO= decrease CO. Trial natriuretic peptide= decrease blood volume. PNS activity increase= decreased heart rate= decrease CO. Decrease body temp.= decrease heart rate= decrease CO blood vessels 3 layers - Answer: tunic intima: endothelium- simple squamous epithelium that is a continuation of the endocardium. Internal elastic lamina- provides distensibility (ability to stretch) and elasticity (recoil) Tunica media: smooth muscle cells- control the diameter of the vessel and amount of blood that flows through. innervated by sympathetic nervous system. tunica externa: dense irregular collagenous connective tissue that prevents over stretching. vasa vasora: provide oxygen and nutrients to outer tunics of blood vessels. arteries of heart have thicker tunics: aorta, veins are thinner. vasoconstriction and vasodilation - Answer: vasoconstriction: diameter of artery is smaller vasodialation: diameter of artery is larger different arteries and veins - Answer: elastic arteries: conduct blood with high blood pressure to organs. Thick elastic laminae. muscular arteries: control blood flow and regulate blood pressure: thick tunic media. arteriole: thinnest artery, control blood flow to tissues, feed capillary beds. venule: thin, drain capillary beds veins: thinner than most arteries, return blood to heart. Lowest pressure. capillaries: smallest blood vessels, have pericytes to help contract. capillary exchange - Answer: where oxygen and nutrients exchange 1. diffusion and osmosis through gaps and fenestration: small molecules through holes in cells and in between cells. 2. diffusion through membranes of endothelial cells: non-polar molecules. 3. transcytosis: endocytosis followed by exocytosis through endothelial cells for larger molecules 3 types of capillaries - Answer: 1. continuous capillaries: tight junctions, no fenestrations. Found in skin, muscle, connective tissue. Least leaky, permit a narrow range of substances. 2. fenestrated capillaries: contain fenestrations. Found in kidney, endocrine glands, small intestine. Moderately leaky, large volumes of fluid and some larger substances. 3. sinusoidal capillaries: discontinuous sheet of endothelium, irregular basal lamina, very large pores. Found in liver, lymphoid organs, bone marrow, spleen. Leakiest- allow large substances to cross capillary walls. blood flow and regulation through capillary bed - Answer: blood in arteriole- through fare channels- capillary beds- venule in through fare there are pre capillary spinchters, control whether blood enters capillary beds. myogenic mechanism: vasoconstriction/dilation due to contractions/relaxation of smooth muscle cells in arterioles. Regulated by arteriolar pressure. metabolic controls: CO2 by production of metabolism and reacts with H2O to create carbonic acid. This (with O2) will cause smooth muscles in atrioles to relax and dilate. blood flow definitions - Answer: blood flow: volume of blood flowing through a vessel, units= mL/min blood pressure: force per unit area exerted on a vessel wall by the contained blood. Units= mmHg systolic/diastolic normal is 120/180 Blood flows from areas of high to low pressure blood flow= change in pressure/peripheral resistance blood pressure increases, blood flow will increase. peripheral resistance - Answer: vessel diameter has the greatest impact. cross-sectional area of a vessel: larger the area, the lower the blood velocity of blood flow. Larger diameter= larger blood flow. Vasoconstriction: high resistance, decreased blood vessel radium (sympathetic nervous system) vasodilation: increased radium of vessels, low resistance (parasympathetic nervous system) water content in blood: dehydrates. As person loses water, blood becomes more viscous and increases resistance, decreasing blood flow. length of vessel: longer vessels increase resistance and decrease blood flow. This can be affected by weight gain and growth. vessel diameter: blood flows in a laminar flow pattern. Blood near the edge of the vessel is slow, center flows faster. larger diameter, the faster the blood can flow. poiseuille's law: flow rate and peripheral resistance are inversely related. viscosity and length change rarely. radius changes often. factors that impact blood pressure - Answer: peripheral resistance, cardiac output, blood volume. cardiac and pressure gradient: delta P= CO*PR CO= strove volume* heart rate. blood volume is higher, pressure is higher and vice versa. vessel compliance: ability of a vessel to stretch. blood pressure falls as blood flows through vasculature. Less pressure is needed in veins because they can stretch a lot more. systolic: pressure in vessel when heart is squeezing blood into it. diastolic: pressure in vessel when heart is filling Blood pressure rises and falls (pulsatile) pulse pressure: change in pressure between systolic and diastolic. Mean Atrial Pressure (MAP) - Answer: MAP= diastolic + (1/3)(systolic-diastolic) 80 mmHg+ (1/3)(120 mmHg - 80 mmHg)= 93 mmHg more time is spent is diastolic pressure. nervous systems and blood pressure - Answer: sympathetic: norepinephrine and epinephrine- increase heart rate and cardiac output, decrease vessel diameter and increase resistance. Makes elevated blood pressure. parasympathetic: acetylcholine acts on SA and AV nodes- decrease heart rate and cause vasodilation. Decrease blood pressure. baroreceptor reflex - Answer: elevated BP: 1. sense elevated BP 2. baroreceptors in carotid sinus and aortic arch detect high BP and fire AP at a high rate via CN IX and CN X 3. signal travels to medulla oblongata 4. autonomic centers in medulla oblongata lower sympathetic activity, raise vessel diameter, lower heart rate 5. decreased BP decreased BP: 1. sense low BP 2. receptors fire AP at lower rate via CN IX and CN X 3. signal to oblongata 4. centers in oblongata raise sympathetic activity, lower diameter, rise heart rate 5. increased BP chemoreceptors - Answer: short term regulation of BP detect disrupted homeostasis: low O2, low pH, high CO2 chemoreceptors raise heart rate, decrease vessel diameter, raise BP (restore homeostasis) peripheral chemoreceptors: located near baroreceptors. Primary role is regulation of breathing. central chemoreceptors: located in medulla oblongata. Primary role is to respond to pH of interstitial fluid of brain. hormones of peripheral resistance and cardiac output - Answer: peripheral resistance: epinephrine, norepinephrine. angiotensin-II, renin: increase BP decreased renin secretion (increased parasympathetic): decreased BP cardiac output: thyroid hormone, epinephrine, norepinephrine: increased BP atria natriuretic peptide: decreased BP long term regulation of BP - Answer: regulated by blood volume. hormones that reduce blood volume: atria natriuretic peptide (ANP): produced by atria cells and stimulates kidneys to excrete water and Na+ hormones that increase blood volume: ADH- produced by hypothalamus and triggers thirst and promotes water retention. renin- produced by kidneys and activates angiotensin-II. angiotensin II- induces thirst, cause Na+ retention, and triggers aldosterone production. aldosterone- produced by adrenal gland and causes retention of Na+ and H2O renin-angiotensin II-aldosterone system (RAAS) hypertension - Answer: elevated blood pressure essential (primary)- etiology unknown; most common. development can be based on genetics, ethnic background, age, lifestyle, sympathetic tone, abnormal RAAS activity. secondary- identifiable cause. Renal artery stenosis (narrowing of arteries serving the kidney) treatment: lifestyle changes- don't smoke, eat healthy, exercise, limit alcohol. dietary: reduce salt, cholesterol, saturated fat drugs: inhibit RAAS pathway: angiotensin-converting enzyme (ACE) inhibitor diuretics inhibit calcium ion channels: prevents Ca2+ mediated vasoconstriction beta-androgenic receptor antagonists (beta-blockers) hypotension - Answer: abnormally low BP reduced blood volume: most common. Blood loss, fluid loss, dehydration. Severe blood loss- hypovolemic shock. treatment- blood transfusion, fluids. decreased CO: decreased strove volume (heart failure), decreased heart rate (drug response), severe reduction in CO- cardiogenic shock. Treatment- cardio stimulatory drugs. vasodilation: histamine release (anaphylactic shock), bacteria infection (septic shock). treatment- vasoconstrictors.