Anatomy 1 Exam 2 - PDF

Biology 223 Human Anatomy and Physiology I Membrane Transport, Membrane Potential, & Biolelectricity Chapter 3 (Sections: 3-1, 3-5, 3-6, 3-7) Chapter 12 (Section: 12-4) cell O U F E... tosol O  Cell membrane is a barrier S...

Biology 223 Human Anatomy and Physiology I Membrane Transport, Membrane Potential, & Biolelectricity Chapter 3 (Sections: 3-1, 3-5, 3-6, 3-7) Chapter 12 (Section: 12-4) cell O U F E... tosol O  Cell membrane is a barrier Separates inside of cell from outside fluid Inside = cytosol = intracellular Outside = extracellular = interstitial Allows inside concentration of electrolytes and other solutes to be different from extracellular concentration of solutes Higher inside: ____, K+ proteins _ (negatively charged) Nat Cl , Ca+2 Higher outside: ____,  Permeability The ease with which substances can cross the cell membrane Nothing passes through an impermeable barrier Anything can pass through a freely permeable barrier selectively permeable Cell membranes are ___________ Different cells have different selectivity due to different transport mechanisms  Transport mechanisms Passive – cell does not expend energy Active – cell expends _________ energy Diffusion (in a solution or across a membrane) Passive random motion of ions and molecules down their concentration gradient Carrier mediated transport (across membrane) ________ passive or _______ active requires transport protein in membrane  Diffusion Movement of a substance from an area of high low concentration to ____ Molecules with no electrical charges Diffuse down or along the chemical concentration gradient of the molecule For charged ions and molecules Diffuse based on electro-chemical gradient Chemical concentration gradient is one driving force Electrical concentration gradient is another driving force Diffusion  Diffusion in body fluids Examples O2 moves from lungs into blood, into interstitial spaces, into cells CO2 moves from cells into interstitial spaces, into blood, out through lungs Water moves across epithelium of digestive tract into body tissues  Diffusion across cell membranes Membrane must be permeable to the substance for diffusion to occur Lipid bilayer portion of cell membranes permeable to O2, CO2 and most hydrophobic molecules _____ not permeable to most large molecules and most hydrophilic molecules Membrane proteins can provide channels for passive diffusion Membrane Permeability  Osmosis Diffusion of water across a semi-permeable membrane in response to solute differences Concentration of water is related to total concentration of all solutes (dissolved materials) including ions, proteins, monomers, polymers, etc. Water moves by diffusion down its concentration gradient  Osmosis Water tends to diffuse across a membrane toward solution containing the higher solute concentration Osmotic pressure = ______ force of water movement into a solution  Tonicity Tonicity - the effects of ___________ extracellular solutions on cells Isotonic = no net osmosis, no net gain or loss of water Hypotonic extracellular solution – less solutes, more water than intracellular solution – water will flow _____ into cell Hypertonic extracellular solution – more solutes, less water than intracellular solution – water will flow ____ out of cell  total Effects of Altered Extracellular Osmolarity > - dissolved NaCl (Im) solute Nat (20sM) - 21  Factors influencing diffusion Distance – concentration gradients effective only over short distances – few cells are more than 125 µm from a blood vessel Diffusion is faster if Molecule is smaller Temperature is higher Concentration gradient is higher * For charged ions, concentration gradient is one driving force, electrical ___________gradient is another driving force  Question What would happen if a cell suddenly became very permeable to K+ ions? + A. K ions would move into the cell i + ① O B. K ions would move out off the cell C. There would be no net movement of K+ ions  Transport mechanisms Diffusion (in a solution or across a membrane) Passive process (no energy required) Random motion of substances down their chemical or electrical concentration gradient Carrier mediated transport (across membrane) Passive (no energy required) or active (energy required) Requires transport protein in membrane  Carrier mediated transport Membrane proteins bind and transport specific molecules or ions Specificity - carrier proteins are generally _________for specific a particular substance Saturation limits – rate of transport subject to number of transport proteins available Regulation – various control factors exist that affect activity of carrier proteins  Max ---------------- - Raansmi s si o n don't see out glucos, unlessglucose concentration is SUPER high [Glucose] facilitated diffusion &  Carrier mediated transport Many carrier proteins transport one substance, one way only Some carrier proteins transport two substances at same time Cotransport – both go same directions across membrane Counter-transport (antiport)– go opposite directions across membrane Nat & k + Energetics of carrier mediated transport Facilitated diffusion – passive Active transport – active  Facilitated Diffusion (across a membrane) Substance moves down conc. gradient energy is supplied by concentration gradient, no ATP needed Requires transport protein different transport proteins for different substances Differs from simple diffusion maximum rate is dependent on availability of transport protein – can reach saturation  Active transport (across a membrane) Active transport Consumes ATP Independent of concentration gradients Examples of active transport include Ion pumps Secondary active transport Active ort transp Na + 2 lit Nat + Nat Dimportant for muscles & nerves *  Secondary Active Transport Nat One substance moves down its conc. gradient energy is supplied by concentration gradient, no ATP needed Another substances moves against its concentration gradient (Glucose) Energy is supplied by concentration gradient of other substances Requires ____________ transport protein * usually with an active (primary) & passive (secondary) ↳ causes energetic concentration gradient  Secondary Active Transport active transport ↓ transport Seconda ↓ secondary primary  Question Which of the following are anions? A. Sodium ions and potassium ions Nat , K + O B. Chloride ions [1- C. Calcium ions Calt D. All of the above are anions E. None of the above are anions  Trans-membrane Potential Difference in electrical potential between inside and outside a cell Resting membrane potential At rest, cells have more __________ negative charge inside than outside _ Higher inside: K+, proteins _ (A = negatively charged anions) Higher outside: Na+, Cl , Ca+2 Na Car O la Not No I sav kt - + K  Trans-membrane potential Electro-chemical gradient Sum of forces of all chemical and electrical gradients acting across the cell membrane Sodium-potassium exchange pump stabilizes resting potential at -70 mV in nerve cells, -85 mV in muscle cells Resting Membrane Potential  of what Opposite Electrochemical Gradients Nat 1 + active transport does t = - = Figure 12–9a, b  Bio-electricity in Nerve & Muscle Cells Ion flow is a form of electrical current Ions move across the membrane through protein channels Driving force is diffusion along electro-chemical gradient (trans-membrane potential is equivalent of a battery) Gated channels - open in response to various stimuli  Bio-electricity in nerve & muscle cells Ion A flow is a form of ____________ electrical current Ions move across the membrane through protein channels Driving force is diffusion along electro-chemical gradient (trans-membrane potential is equivalent of a battery) Gated channels - open in response to various stimuli  Types of regulated gated channels in muscle cells Chemically regulated channels aka: Chemically gated channels - neurotransmitters Open or close when they bind specific chemicals Voltage-regulated channels aka: Voltage gated channels Open or close in response to level of trans- membrane potential  X Nat are mechanic (voltage + Bioelectrical current x + 1x  Example of chemically regulated gated channel Acetylcholine (ACh) gated sodium ion channel Neuromuscular junction – synapse between nerve cell and muscle cell Nerve cell process releases acetylcholine by exocytosis ACh binds to receptor on gated sodium channels in muscle membrane, causing sodium channel to open ·  Example of voltage regulated gated channel Found in excitable membranes membranes capable of having action potentials at resting membrane potential, most voltage & regulated channels are ________ closed Nerve cell membranes are excitable Cell membranes of muscle cells are excitable ↳ 00 = 00  Voltage regulated ion channels Change in level of trans-membrane potential opens or closes voltage regulated ion channels Depolarization – trans-membrane potential becomes less negative Hyperpolarization – trans-membrane potential becomes more negative Repolarization – trans-membrane potential returns toward resting potential after being depolarized Depolarization and Hyperpolarization & D A  Na is ligand-gateda O  moves bice & triced  (cell) muscle fasicles Surf I 1 I ↑ - ' - = - - & - S ' ~ 12 &  - ⑧ deen Fascia Endo-peri-Epi  muscle limited thin A-acute (thin) thick M- massive (thick) Actin Myosin (T tubule &Zareas of sarcoplasmic reticulum) (voltage-gated channels) T-tubules Calt S JJ o do o d I : · X ↓ SRx X ⑧ & + + & + 2 X SR Ca2 8E = T + ↓ T-tubule * CrIt ↑+ + # shorten Hefty (thick) [ recent rat Isarcomere  filaments in line * titin keeps : ↳ helke i O sarcomere narrow width  relaxed contracted Hor F fully (no. band) Thick thir cross bridges ATP contraction troponin  troponin actin release when muscle contracts , active site opens for myosinhead to bind break down ATP, makes ADP + P ; bind , pivot let , , go energize detaching low E actin  synaptic terminal  chemically depolarizes Esterase T tubules & Asintere O Ca Cast birds troponin > - tropomyosin trapomyosin > - moves myosin lead binds to activ > - pivot of myosin head pulls on actin + detachment of myosin head with binding of ATP ATP "cross-bridge cycling " of  ends close A SR  calcium ion myosin AChE sodium ion  ↑ tropomyosin disconnect ·  stoys releasing A Ch autoimmune disorder > - ↳ r trusale can't relax > - can't contract Eautoimmune  Biology 323 Human Anatomy and Physiology I Tension Production Energy Use and Muscular Activity Contraction in muscle cells leads to muscle tension Figure 10.9 Figure 10.9  Tension “Pulling Strength” Sliding of actin and myosin filaments causes sarcomere shortening In a muscle cell, all sarcomeres shorten causing the muscle cell to shorten Tension in a muscle depends on: Tension that develops in individual muscle cells during contraction __________ number of muscle cells that contract Amount of shortening depends on tension and resistance  Fiber Shortening As sarcomeres shorten, muscle cell shortens, producing tension Pulls on connective tissue and bone to which it is attached  Tension Tension produced in individual muscle fibers (cells) can vary due to: Length-tension relationship Frequency of stimulation by motor neuron Tension produced by entire muscle can vary due to: Number of muscle cells receiving nerve stimulation, commanding them to contract Muscle cells are grouped in motor units  Length-Tension relationships Amount of tension depends on number of cross bridges formed Depends on degree of overlap of actin & myosin filaments Skeletal muscle contracts most forcefully over a lengths narrow range of resting __________ No cross-bridge Formation , notension  Tension production by muscle fibers: Frequency of Stimulation Twitch Cycle of contraction, relaxation produced by a ______action single potential in a muscle cell not typical of must normal skeletal muscle activity  Twitch Latent phase - Action potential occurs No contraction until Ca+2 is released from SR Contraction phase -Tension rises to peak Ca+2 moves tropomyosin off actin active sites Myosin cross bridges form, actin is pulled Relaxation phase - Tension falls to resting levels Ca+2 is pumped back into SR Actin sites covered by tropomyosin No cross bridges remain · ·  Tension production by muscle fibers: Frequency of Stimulation Most muscular activities involve sustained muscular contractions Produced by high __________ frequency of action potentials in muscle cell Produced in response to high frequency of action potentials in motor neuron (high frequency of stimulation) Summation of tension produces greater tension  Summation Repeated stimulation produced before relaxation phase has been completed Summation of tension caused by build up of calcium ions in sarcoplasm Complete tetanus maxsustained contraction - Incomplete tetanus -submaximal sustainable contraction “Tetanus” disease caused by Clostridium tetani bacteria Bacterial toxin causes high frequency of action potentials in motor neurons Treppe vs. Wave Summation Incomplete vs. Complete Tetanus  Tension Tension produced in individual muscle fibers (cells) can vary due to Length-tension relationship Frequency of stimulation Tension produced by entire muscle can vary even more widely due to Number of muscle cells receiving nerve stimulation, commanding them to contract Muscle cells are grouped in motor units  Tension production by skeletal muscles Number of active motor units Motor units All the muscle fibers innervated by one motor neuron Amount of tension produced in a muscle determined by number of motor units activated Asynchronous motor unit summation for sustained contractions  Tension production by skeletal muscles Number of active motor units Differences in number and size of motor units in different muscles determines precision of control of movements Small motor unit - precise control hands face speaking , , One motor neuron innervates a ________ small number of muscle fibers limbs Large motor unit - gross movement control torso , large number of One motor neuron innervates a _______ muscle fibers Motor Units Asynchronous motor unit summation  Muscle Tone Resting tension in a skeletal muscle In any muscle, _______motor some units are always active; tense and firm the muscle Which motor units are active is constantly changing, muscle tone is not produced by a specific subset of motor units Stabilizes bones and joints Greater resting muscle tone causes higher resting rate of metabolism  Why is it difficult to contract a muscle that has been overstretched? A. Little or no calcium can be released from the sarcoplasmic reticulum if it is stretched B. Actin becomes detached from the Z disks when muscle fibers are over stretched C. Transverse tubules can not conduct action potentials when distorted by stretching 8 D. Few if any myosin-actin cross bridges can form when sarcomeres are overextended E. The neuromuscular junction becomes detached when a muscle is too stretched  Contractions Isotonic and Isometric Isotonic - tension rises, length of muscle changes Concentric – muscle gets shorter Eccentric – muscle gets longer Isotonic CONCENTRIC contractions Isotonic ECCENTRIC contraction  Contractions measurement Isotonic and Isometric same Isometric - tension rises, length of muscle remains constant length of doesn't don't muscle muscle change , move tension increases Isometic Contractions p  Lengthening a muscle No active mechanism for muscle fiber elongation A muscle cell does not cause itself to lengthen after contraction process ends Returns to resting length due to contraction of opposing muscle groups gravity Some elastic recoil in connective tissue  Muscle Metabolism Figure 10.20  Energy Use and Muscle Contraction Muscle contraction requires large amounts of _____ ATP Muscle cells stores only enough high energy molecules to sustain contraction until additional ATP can be generated ATP and ____________(CP) Creatine Phosphate reserves last ~ 15 seconds once contraction begins Muscle cell must generate ATP at approx. the same rate as it is used for remainder of contraction  # Creative-Phosphate ADP Creatine + ATP + - at rest -- > start -"exercise  Creatine Phosphate and ATP Creatine Phosphate (CP) reserves ATP not used for long term storage of energy. P At rest : make more C. At start of exercise : make more ATP  Cellular Respiration ATP generation Aerobic cellular respiration: most ATP needed for ________ resting muscle and for moderate levels of muscle activity always going added only after moderate activity Aerobic AND _____________ anaerobic glycolysis pathways needed to generate additional ATP for PEAK PERFORMANCE  Aerobic metabolism AEROBIC Cellular respiration uses O2 - releases CO2 Occurs in mitochondria Citric Acid Cycle ____ CO2 is produced Electron transport chain _____ ATP synthesis ___ Or is used  Oxidation : lose e- Reduction gain : e- Aerobic Cellular Respiration A completing breakdown carbon A I of organic & > - > - - - Figure 25–2 (Navigator)  Muscle cell ATP generation Resting muscle fibers rely on aerobic metabolism of fatty ________to acids generate ATP FA absorbed from circulation broken down to 2-carbon units of acetyl CoA (Beta- Oxidation) which enter DIRECTLY into the Citric Acid Cycle Excess ATP used to store glucose into ___________, glycogen create creatine phosphate Resting Muscle Metabolism ~ Isseconds  Muscle cell ATP generation Contracting muscle fibers rely on aerobic ____ AND anaerobic metabolism of glucose Amount of aerobic vs. anaerobic metabolism depends on intensity of muscle contraction Moderate vs. Peak Glucose comes from circulation & breakdown of glycogen reserves within muscle cell Moderately Active Muscle Metabolism Glycolysis f no lactic acid production  Glucose metabolism in muscle cells Pyruvate metabolism - anaerobic If oxygen delivery to cells is too slow to allow all of pyruvate to be metabolized aerobically by cellular respiration, rest of lactic acid pyruvate converted to __________ Conversion of pyruvate to lactic acid recycles cofactors needed by glycolysis enzymes  attate Why convert lactate to pyruvate? 2 net ATP M 2 pyruvate Glucose > - · N Need lactate Peak Activity Muscle Metabolism other 3 glycolysis Glycolysis aerobic is maxed out , anaerobic works now  Anaerobic metabolism Anaerobic metabolism produces ATP ________ rapidly Allows muscle cell to generate additional ATP when mitochondrial cellular respiration pathway is unable to meet cell’s energy demands Disadvantages Inefficient use of glucose Lactic acid _______ lowers intracellular pH  Recovery period Begins immediately after activity ends kebt Oxygen _______ (excess post-exercise oxygen consumption) resting period to Amount of oxygen required during ________ make enough ATP to restore muscle to normal conditions Rebuild ATP and creatine phosphate levels Recycle lactic acid to make pyruvate Rebuild glycogen reserves  Oxygen Debt anaerobic Debt d = more realistic S a AT and - · · time  Muscle Fatigue Fatigued muscle – a muscle that can no longer perform at required level of activity Possible causes of fatigue Exhaustion of _________ energy resources lactic acid Build up of __________and lowering of pH Psychological fatigue =>  tension time types  Oxidative glycolytic & Joby Red gendomysium perimysium & White & bigger produce more tension , Mitochondria myoglobin (causes dark ment color) also increase rate of O2 diffusion ,  ⑳ · myoglobin ⑳ Hemoglobin  - utilize more of glycolysis glycogen rapidly anaerobic  genetically fast intermediate fast fast > - At cannot produce more fibers , butcan produce slow As fast more intermediate from fast A diameter glycolysis ATP/CP mitochondrial i & I I I " " I ! " i i S I · , I i Y ↑ " " myofibrils ⑭ : promote transcription of genes could cause cells to die · - slows down pyruvate  Prioritivegucseno the brain) lactate - takes produceeose to - increasing gene expression with more exercise regularly A Greater of capacity acrobia respiration *  No need to nemorize Skeletal muscle : Or binding protein in  tibetans Euro sherpas high flor alt. fatigue scar tissue  bone hollow internal an - B  fused of cells depolarization Syncyfirm mass [NOT Sencytium) : -> unit can spread that function as a from one cell to another multinucleate gap junctions cell#) cell #2 ~ - Desmosomes bas junctions cell NO SARCOMERES  scattered shorten & twist create attached to activ thin filaments , Dense bodies : Strong structural proteins , cell-cell connection , in location with gap junctions  6 Cattached to actin) 6 G O Plasticity - myosin isn't fixedPace tetanic  &gaaction & myosin pulls on actin tetanic twitch tetanic  motor neurons & ↑ or t heart rate pacemaker cells autonomic  without ↑ HR ↓ HR  layers autonomic J - arrector pilli muscles high  & breaks down ACh ⑧ - > - over contracted muscles other systems contraction  injury , infection -exercise , t rare ↳ autoimmune disorders ↳enc! # not over contracted contracted flaccid flaccid spastic flaccid flaccid spastic -usually from crushing injury > - Secondary MORE LESS repolarization depolarization released from SR for muscle contraction  Cslow twitch) O Genetic common more inmales  CTACTGCTECTGCTG know this not this  myotonic dystrophy protein kinase & + less enzyme > more severe more CTG repeat - case  between ELM & Cytoskeleton structural protein , connection - Every big)  (very large chance of mutation with larger protein -higher Collagen of Endomysium [ & if dystrophin functional then the , muscle fiber tension A won't isn't produce