Exam 1 Study Guide Ex Phys PDF

KNHS 3319 Exam 1 Study Guide The exam will include multiple choice, T/F, and short answer. This exam is 50 points. **Chapter 1: Structure and Function of Skeletal Muscle** I. [Types of muscle tissue] a. Know which are voluntary vs involuntary: Skeletal is voluntary, cardiac and sm...

KNHS 3319 Exam 1 Study Guide The exam will include multiple choice, T/F, and short answer. This exam is 50 points. **Chapter 1: Structure and Function of Skeletal Muscle** I. [Types of muscle tissue] a. Know which are voluntary vs involuntary: Skeletal is voluntary, cardiac and smooth are involuntary. II. [Anatomy of skeletal muscle:] b. What is a myofibril and what is a sarcomere? Myofibril are composed of thick and thin filaments, they run parallel. Muscle\>fascicle\>muscle fiber\> myofibril. Sarcomere is basic functional unit of a myofibril and contractile unit of muscle. They contain myosin and actin. i. Myosin has two protein strands twisted together and forms globular heads (myosin heads). ii. Actin is composed of troponin and tropomyosin. Tropomyosin twists around actin. Troponin attaches to both actin and tropomyosin at regular interval. Contains sites where myosin heads can bind. c. Sarcomeres iii. Made up of actin and myosin 1. Know the anatomy of actin and myosin as it relates to their ability to complete cross-bridge cycling. III. [Muscle Fiber Contraction] d. What is an alpha motor neuron? It connects and innervates with skeletal muscle fibers, cause muscle contraction to generate movement. e. Know the steps associated with EC-Coupling (I HIGHLY recommend drawing it out to help your retention). 2. AP fired-\>Ach stimulated-\>Ach is released and then binds to receptors-\>Depolarization occurs across plasmalemma due to Na+ coming (high to low)-\>triggers Ca2+ from SR-\>depolarization down t-tubule-\> ca2+ binds to troponin (high affinity)-\>moved tropomyosin-\>myosin acts to actin. f. What is the role of calcium? Calcium binds to troponin (high affinity, strong pull). This initiates contraction process by removing tropomyosin off the myosin binding site (at rest it covers myosin-binding sites). Once that is lifted, myosin heads can attach to actin. g. Sliding Filament Theory iv. Know the associated steps. When myosin head binds to actin, it causes a change in shape of the cross-bridge. This change in shape causes the myosin head to shift, pulling the actin towards the center of the sarcomere. Tilting of the myosin head=power stroke. After myosin head tilts, it breaks away from the active site and attaches to a new site. IV. [Energy for muscle contraction] h. How is ATP used for contraction? For relaxation? Myosin head has two binding site: actin and ATP. ATP supplies the energy necessary for the muscle contraction to occur. ATP is also required to pump Ca2+ back into SR. It is needed for contraction and relaxation. As long as calcium is available, a muscle contraction will continue. i. What is ATPase and why is it important? Located on the myosin head, splits the ATP to yield ADP and inorganic phosphate. Energy releases from the breakdown of ATP causes the power stroke of the myosin head. V. [Muscle fiber types] j. Know the difference between type I and type II v. Understand when type I vs. type II muscle fibers are used for varying exercise intensities. Skeletal muscle has two types of fibers: type 1 and type 2. Type 1 (running, swimmining): slow twitch. 50% of fibers in an avg. muscle. Slow form of myosin ATPase, smaller neurons. Type 2: Fast twitch. Fast form of myosin ATPase (fast contract), cross bridges form rapidly. Also deliver calcium into the cell quickly. (better sprinters) since has high developed SR. Two types of fast: a is most frequently recruited and intermediate fibers. B is fast twitch. VI. [Length-Tension relationship] k. Know the overall message of this relationship l. Be able to describe in your own words. Optimal sarcomere length equals optimal overlap of actin and myosin. Maximizes the potential for cross-bridge interaction. If too short or too long, little or no force occurs. **Chapter 2: Fuel for Exercise** I. [3 major substrates:] a. Carbohydrates i. Primary energy source? Glucose- which is transported to other body tissues via blood. Primary energy source for the muscles and the brain. Lack of glucose causes cognitive impairments. ii. What happens during prolonged exercise? Muscle and liver glycogen is limited and can be depleted during prolonged exercises. b. Fat iii. Primary energy source? Free fatty acids and glycerol. iv. When are fats used during exercise? Less intense exercises prolonged. c. Protein v. Primary energy source? Amino acids. vi. Gluconeogenesis converts AA into glucose. II. [Rate of energy:] d. What is rate determined by? Availability of primary substrate and enzyme activity. e. What is the mass action effect? If one substrate is more available cells will rely on that more i.e. carbs f. What role do enzymes play with rate of energy production? Do not start chemical reactions to control rate of free energy. Do speed up the breakdown of chemical compounds. Speeds up reactions by lowering activation energy for a chemical reaction to occur. vii. Define rate-limiting enzymes. In the beginning of the pathway. Controlled by negative feedback. - Substrates further down the pathway can decrease enzyme activity once enough by product is produced. III. [Basic Energy Systems (known which are anaerobic vs aerobic)] g. ATP-PCr system Anaerobic viii. How many ATP produced? 1 ix. How long can this system provide energy? 3-15 secs x. Know the pathway and associated enzyme. Pathway: Pcr donates Pi to ADP to yield ATP. Enzyme is creatine kinase. h. Glycolysis Anaerobic xi. How many ATP produced? Glucose? 2 Glycogen? 3 Why is there a difference? Because for glucose, it must convert to glucose -6-phosphate first and it can directly enter glycolysis without initial phosphorylation reaction that consumes ATP. In glycogen, the initial step bypasses the need to invest ATp molecule which results in gain of one atp molecule. xii. How long can this system provide energy? 2 minutes xiii. How many total reactions are in this pathway? 10-12 reactions total xiv. At the end of glycolysis, what is created? pyruvic acid With and without oxygen? Yes, in aerobic: pyruvate enters the citric acid cycle and undergoes oxidative phosphorylation. In anaerobic pyruvate converts to lactate through anaerobic glycolysis. xv. Know the pros and cons of glycolysis i. Oxidation of Carbs: xvi. Glycolysis: can occur with or without O2. 1. Anaerobic vs aerobic production. Anaerobic glycolysis: produces lactic acid. Aerobic glycolysis: pyruvic acid is converted to acetyl coenzyme a. Happens in cytosol. xvii. Krebs cycle 2. What product enters the Krebs \*\*know how MANY ATP are produced. Acetyl coA is entered. Rate limiting enzyme is isocitrate dehydrogenase. Glucose is 32 and glycogen is 33. xviii. ETC 3. In which pathways are hydrogen ions released? During glycolysis and krebs cycle. Which substrate carries the hydrogen ions and electrons to the ETC? NADH and FADH2 4. Where does ETC take place? Inner Mitochondrial wall 5. Remember, it is necessary to build up a concentration gradient to create ATP. xix. \*\*remember I do **not** want you to memorize each step within each pathway, *think big picture* xx. What are the players in the oxidative system which produce ATP? NADH, FADH2, protein complexes, ATP synthase j. Oxidation of Fat xxi. In order to use triglycerides, how must it be broken down? 1 molecule of glycerol and 3 FFA molecules. (lipolysis) xxii. B-Oxidation 6. Define. Conversion of FFA to acetyl coA 7. Where does this occur? Mitochondria 8. Purpose of B-oxidation? FFAs must be converted into acetyl coA before they can be used for energy metabolism. a. Know the phases b. Phase 1: to be used for energy, trigylcerides must be broken down into glycerol and 3 fatty acids. FFA then can be gone to blood to any cell able to metabolize FFA. c. Phase 2: FFA enters a cell through fatty acid transporter. Then FFA crosses the mitochondrial wall. In order for FFA to cross it must be activated to acyl coA- requires atp. Once activated it goes to mitochondria. d. Phase 3: series of steps where 2 carbon acyl units ae chopped at the carbon chain of the FFA, which then become acetyl coA and enters the krebs cycle. i. For Phase 3The number of acetyl CoAs that enter Krebs depends on the length of the carbon chain of the FFA k. Oxidation of Protein xxiii. How often is this system used? rarely l. Interaction of Energy Systems xxiv. Is one system ever 100% dominant? No xxv. Cross-over concept 9. Below 60% max oxygen- which system is primary? Fat metabolism 10. Above 75% of max oxygen- which system is primary? Carb metabolism 11. The crossover point is affected by endurance training. With endurance training, adaptions occur within the muscle fibers (primarily type I) and oxidation of FFAs is promoted. Because of this, muscle glycogen is spared, therefore the crossover point will shift to the RIGHT with training **Chapter 3: Neural Control of Muscle** I. [Nervous System] a. Central: Brain and spinal cord a. Components? b. Peripheral: b. Sensory -- afferent: incoming, informs brain what is going inside the body. c. Motor - Efferent: outgoing, sends info from NS to tissues and organs in the body. - Somatic: voluntary, to skeletal muscle - Autonomic: involuntary, internal organs - Sympathetic - Parasympathetic II. [Structures of the NS:] c. What is a neuron? Basic structural unit of a NS. Same structure everywhere in the body. d. Cell body -- contains the nucleus, cell processes (dendrites and axon) radiate out. e. Dendrites- neuron's receiver, receive action potentials from other neurons, carry impulses towards the cell body. f. Axon -- Neuron's transmitter, sends impulses away; contain end branches, terminals and neurotransmitters (used for communication w other neurons.) d. How do the periphery and brain communicate? Via electrical signals. Must be generated by stimulus, propagated down an axon, and must be transmitted to next cell. III. [Resting Membrane Potential] e. What is the resting membrane potential? Difference of electrical charges between outside and inside the cell. At rest RMP is -70 mV. f. High concentration of what on the inside and outside of the membrane? Na+ outside of the cell is higher concentration, and high concentration of K+ inside the cell. g. Sodium-Potassium pump: what is pumped in and pumped out? Moves 3 Na+ outside the cell and 2 K+ inside the cell. Causes more positively charged ions outside the cell, thus creating the RMP. g. Primary function of this pump? Maintaining a RMP of -70. h. Define and understand depolarization and hyperpolarization. Depolarization: inside of the cell is less negative(More positive), results of more Na+ channels open. Hyperpolarization: inside of the cell becomes too negative, with more K+ channels open. IV. [Action Potentials] i. Graded AP h. What type of triggers cause a GP. Triggered by a change in the environment of the neuron: - Generated by incoming signals from dendrites - Changes in chemical concentrations - Changes in temp - Changes in pressure i. Remember that GPs are LOCALIZED and the ripple effect we drew out in class j. GPs can lead to an AP, but they [must] be very strong. GP reach -55 an AP will occur j. Action Potentials k. Please be very comfortable with the diagram, we spent a lot of time on this in class l. What is an absolute refractory period and a relative refractory period? Absolute: occurs during depolarization, Na+ channels open and cant open more, neuron cant respond to other stimulus. Relative: during repolarization, neuron responds to strong stimulus, K+ channels open and Na+ can open. m. Synapse: 1. What is a synapse? Junction or gap between neurons. 2. Define a presynaptic and postsynaptic neuron. Presynaptic: neuron sending the AP. Postsynaptic: neuron receiving the AP. k. Neurotransmitters: n. Acetylcholine vs. norepinephrine. Acetylcholine: stimulates skeletal muscle contraction, mediates parasympathetic NS effects. Cholinergic releases it. Norepinephrine: mediates sympathetic NS effects. Adrenergic releases it. l. Postsynaptic response: o. What is an EPSP? Depolarizing, promotes AP. p. What is an IPSP? Hyperpolarization and inhibitory, prevents AP. V. [Central Nervous System] m. The brain is composed of what? Cerebrum, cerebellum, brain stem, and diencephalon. VI. [Peripheral Nervous System]: q. Two major divisions: 3. Sensory a. Where is information transmitted? Periphery to brain b. Know the types of sensory receptors - Mechanoreceptors: respond to physical touches - Thermoreceptors: respond to temperature - Nociceptors: respond to painful stimuli - Photoreceptors: respond to light to allow vision - Chemoreceptors: respond to chemical stimuli. 4. Motor c. Where is information transmitted? Brain to periphery d. Two subdivisions: i. Autonomic: 1. Involuntary regulation 2. Sympathetic a. What would happen inside the body if this system is stimulated? Prepares body for exercise, HR and BP, airway diameter increases. 3. Parasympathetic b. What would happen inside the body if this system is stimulated? Opposes sympathetic stuff, active at rest, increase urine and digestion, and decreases airway and vessels. ii. Somatic 4. Stimulated skeletal muscle activity r. Sensory-Motor Integration 5. What are the 5 steps? 1) stimulus sensed by sensory receptors. 2) sensory AP send on sensory neurons to CNS. 3) CNS interprets info and sends out appropriate response. 4) motor AP send out on alpha neurons. 5) arrives at skeletal muscle and response occurs. 6. What is: reflex activity? an automatic, involuntary response to a specific stimulus, occurring rapidly and without conscious thought **Chapter 4: Hormonal Control During Exercise** I. What is the endocrine system responsible for? Fine tuning the physiological response to a disturbance in homeostasis. II. Endocrine and nervous system work together, but have different means of communication. What are these communication methods? Endocrine system has chemical communications and is long lived. Nervous system has electrical signals and is short lived. III. What are target cells? Hormones travel in blood to target cells. Possess specific hormones receptors, regulates activity of the specific tissue. IV. Steroid Hormones: i. Lipid soluble = diffuses through cell membrane (so, receptors are located INSIDE the cell) 1. Hormone binds to the receptors INSIDE the cell 2. Hormone-receptor complex activates cell's DNA, forming mRNA 3. mRNA directs protein synthesis (or whatever affect the hormone has triggered) ii. Secreted by which 4 glands? Adrenal cortex (cortisol, aldosterone), ovaries (estrogen, progesterone), placenta (estrogen, progesterone), and Testes (testosterone). V. Nonsteroid Hormones: iii. Not lipid soluble = cannot cross cell membrane (so, receptors are located along the cell membrane) 4. Hormone must bind with a receptor on the cell membrane 5. Hormone-receptor complex activates adenylate cyclase 6. Adenylate cyclase AND ATP form a second messenger (ex, cAMP) 7. Second messenger purpose = carry out the hormone effects iv. Made up of two groups- know the difference between the groups. [Protein or peptide hormones:] most nonsteroid hormones, from pancreas, hypothalamus, and pituitary gland. [Amino-acid derived hormones]: thyroid hormones T3 and T4, and adrenal medulla hormones. VI. Why are hormones secreted in bursts? Plasma concentrations fluctuate over minutes/ hours. VII. What triggers hormone bursts? Secretion regulated by negative feedback. VIII. Hormones MUST bind to a receptor in order to exert an affect v. Cells can alter their sensitivity for a hormone through: 8. Downregulation- decrease number of receptors, therefore in order for the response to happen, increase concentration 9. Upregulation- increase number of receptors, requires normal or lower concentration levels to carry out to response IX. What is a hormone-receptor complex? Hormone and receptor bonded. If there is no receptor on the cell surface, there is no hormone effect. X. Main function of the endocrine system during exercise = regulation of metabolism vi. Hormones ensure there is adequate glucose and FFA for energy XI. What are the 4 major endocrine glands responsible? Adrenal glands, anterior pituitary gland, thyroid gland, and pancreas. vii. Anterior Pituitary Gland: 10. Secretes hormones in response to the hypothalamus a. GROWTH HORMONE i. Stimulates fat metabolism, promotes muscle growth ii. \*\*GH release is proportional to exercise intensity because it stimulates fat metabolism viii. Thyroid Gland: 11. Secretes T3 and T4 (nonsteroid) b. Increases protein synthesis, glucose uptake, rates of glycolysis and gluconeogenesis, FFA mobilization ix. Adrenal Medulla: 12. Releases: c. Catecholamines (epinephrine and norepinephrine) d. Corticosteroids (Cortisol) -- stimulates gluconeogenesis, increases FFA mobilization x. Pancreas: 13. Secretes: e. Insulin: facilitates transport of glucose into the cell f. Glucagon: releases when glucose levels are low, therefore: iii. Promotes glycogenolysis and gluconeogenesis I. **Chapter 5: Energy Expenditure and Fatigue** a. [Measuring EE:] i. Direct calorimetry 1. Define: measurement of the amount of heat produced by the body 2. What does it measure? Heat from the body 3. Pros and cons? Pros: accurate measurement over time, good for resting metabolic measurements. Cons: expensive, heat is added by exercise equipment, measurement errors created by sweat, neither practical nor precise for exercise. ii. Indirect calorimetry: measurement of the respiratory exchange of oxygen and carbon dioxide. 4. When is this measurement accurate? Steady-state oxidative metabolism 5. What are the problems associated with measuring carbon dioxide? Older methods are accurate but slow, new methods are faster but expensive. b. [Respiratory Exchange Ratio:] iii. What does this measure? Rate of carbon dioxide released and oxygen consumed 6. Necessary to identify the food substrate being utilized iv. What system(s) are used when the RER is 1? Glucose/glycogen 0.7? fat oxidation 0.78? the body is at rest c. [Basal Metabolic Rate:] v. How is this calculated? In a thermoneutral environment following 8 hours of sleep followed by a 12 hour fast. vi. What is BMR directly related to? Individual's fat free mass. vii. What can affect BMR? Body surface area, age, stress, hormones, and body temperature. d. [Resting Metabolic Rate:] viii. Easier than BMR? Why? Its not as strict. ix. What is RMR for a typical individual? 1,200-2,400 kcal/day e. [What is VO2max?] Maximal oxygen uptake x. What is VO2 peak? Volitional fatigue is typically reached. xi. How is VO2max expressed? L/Min xii. Typical value for an untrained athlete? 20 ml/kg/min Elite? 80-84ml/kg/min xiii. What can alter VO2max? Age and gender f. [What is oxygen deficit? From rest to exercise, oxygen demand is greater than oxygen consumed. What is EPOC? Excess postexercise oxygen consumption] g. [Lactate threshold] xiv. Define point at which blood lactate accumulation increases xv. How is this expressed? Percentage of VO2 Max h. [Fatigue:] xvi. Define, decrements in muscular performance with continued effort, accompanied by sensations of tiredness. Inability to maintain required power output to continue muscular work at given intensity. how can it be reversed? From rest xvii. Major causes? Inadequate energy delivery, accumulation of metabolic by-products, failure of the muscle fiber's contractile mechanism, and altered neural control of muscle contraction. xviii. A sensation of fatigue coincides with a decrease in concentration of muscle glycogen OR rate of depletion?