HK150_studyguide1.docx

**Exam \#1 Study Guide** *The exam will consist of 50 multiple-choice or T/F questions.* *Concentrate on lecture notes.* **Specifically, you should be able to answer the following questions or understand the following concepts:** **Control of the Internal Environment/Physiological Overview---Cha...

**Exam \#1 Study Guide** *The exam will consist of 50 multiple-choice or T/F questions.* *Concentrate on lecture notes.* **Specifically, you should be able to answer the following questions or understand the following concepts:** **Control of the Internal Environment/Physiological Overview---Chapter 2** - **Homeostasis** is the process by which living organisms regulate their internal environment to maintain a stable, constant condition, despite external changes. This stability is crucial for survival and proper functioning. -Body temperature regulation (thermoregulation) -Blood glucose regulation (via insulin and glucagon) -Maintenance of blood pressure **Steady-state** refers to a condition in which a variable (such as temperature, concentration of a substance, or metabolic rate) remains constant over time, but unlike equilibrium, it requires continuous energy input to maintain this state. - **Homeostasis** focuses on maintaining internal stability (via feedback systems), while **Steady state** refers to a constant condition maintained by energy-dependent processes. Both are essential for keeping biological systems functioning properly. - - Nervous System and Endocrine System - [Negative Feedback:] A control mechanism that **reverses** a change in a system to bring it back to its normal state. If something in the body goes too high or too low, the system activates to correct it and bring it back to balance (homeostasis). ex: **Body temperature regulation**. If your body gets too hot, you sweat to cool down. If it\'s too cold, you shiver to warm up. Main Goal: **Stability**. Keeps things steady by opposing the change. [Positive Feedback:] A control mechanism that **amplifies** a change, making it more extreme. Once the process starts, the system keeps pushing it in the same direction until a specific goal is reached ex: **Childbirth**. During labor, contractions get stronger and stronger due to the hormone oxytocin until the baby is born. Main Goal: **Acceleration**. Moves things forward until the process is complete. [Differences between systems: ] **-Negative Feedback** brings things **back to normal**; it\'s about balance (e.g., body temperature). **-Positive Feedback** keeps things going **until a goal** is reached, like speeding up labor during childbirth. -Negative feedback is common for maintaining everyday stability, while positive feedback is rare and usually happens in special events. - **Bioenergetics---Chapter 3** - - - **Glycogenesis** stores glucose as glycogen in the liver and muscles. **Lipogenesis** converts excess nutrients into fat and stores it in fat cells. - 1\) Muscle contractions (during exercise) are the stimuli needed to trigger glucose entering from the bloodstream (circulation) into the muscle cell. - - Oxidation refers to the removal of an electron. (H+ contains 1 e-) Thus, a molecule that loses hydrogen also loses an electron and is "oxidized". - \~25% of chemical energy in food is harnessed to perform cellular work (donated to Pi and ADP to form ATP = work) \~75% of chemical bond energy is released as heat (combusted; cannot be used to do work) - Proteins that regulate (accelerate) the speed of a chemical reaction without being changed by the reaction (lock and key) \[Enzymes generally catalyze chemical reactions in one direction, but the reversibility of the reaction depends on several factors, including the nature of the reaction itself, the concentration of substrates and products, and the specific enzyme involved.\] - Phosphocreatine - Promotes muscle growth, allowing a more efficient recovery from physical activity. - Anaerobic metabolism, specifically glycolysis, occurs in the **cytoplasm** of the cell. During glycolysis, glucose is broken down into pyruvate, yielding ATP and NADH, without requiring oxygen. Aerobic Metabolism: consists of three stages, each occurring in different parts of the cell: 1. 2. 3. - - **Glycolysis**: - - - - **Citric Acid Cycle (Krebs Cycle)**: - - - - **Oxidative Phosphorylation (Electron Transport Chain and Chemiosmosis)**: - - - - - **NAD (Nicotinamide Adenine Dinucleotide)**: - - **FAD (Flavin Adenine Dinucleotide)**: - - NAD and FAD are important because they act like **batteries** that store and transfer energy. Without them, your cells wouldn't be able to make enough ATP, which is the fuel they need to function and keep you moving. - Harvest energy from NADH and convert it to ATP and water. - Oxygen is crucial for **aerobic metabolism** and life because it plays a key role in **producing energy (ATP)**, which cells need to function and survive. (In short, oxygen allows cells to produce enough energy to maintain all vital processes in the body, making it essential for life.) - - - PCR: Creatine Kinase (CK) Glycolysis: Phosphofructokinase (PFK) Krebs Cycle: Isocitrate dehydrogenase - ### 1. Creatine Kinase (Phosphocreatine System) - - - - ### 2. Phosphofructokinase-1 (PFK-1) (Glycolysis) - - - - - - ### 3. Isocitrate Dehydrogenase (Krebs Cycle) - - - **Exercise Metabolism---Chapter 4** - **245 mL/min** - **More Oxygen Needed**: When you exercise, your muscles use more energy, which means they need more oxygen. So, VO2\\text{VO}\_2VO2​ goes up to provide that extra oxygen. - ### O₂ Deficit at the Beginning of Exercise: - - - ### EPOC at the End of Exercise: - - - - - - \***O₂ deficit** happens because your body takes time to deliver enough oxygen at the start of exercise, while **EPOC** occurs afterward as your body uses extra oxygen to recover and restore energy levels.\* - ### Lower O₂ Deficit in Trained Individuals: - - ### Higher VO₂ Max in Trained Individuals: - - \*trained individuals have a lower O₂ deficit because their bodies respond faster and more efficiently to oxygen demands during exercise. They also have a higher VO₂ max because their cardiovascular and muscular systems are better equipped to utilize oxygen effectively\* - Resynthesis of phosphocreatine Elevated heart rate and breathing (heart and diaphragm contraction) Elevated body temperature (sweat) Elevated epinephrine & norepinephrine (both increase metabolic rate) Elimination of lactic acid - First 1--5 seconds of exercise \- ATP via PCr Exercise longer than 5 sec, but \10 min: 100% aerobic - **The phosphocreatine system** is the fastest way for your muscles to produce ATP at the start of exercise, providing immediate energy for short bursts of activity. - **Carbohydrates** dominate in high-intensity, short-duration exercises. **Fat** is the main fuel for low-to-moderate intensity and longer-duration exercises. **Amino acids** are used minimally and only in specific conditions (like prolonged endurance exercise or when other fuel sources are depleted). - This refers to the idea that as exercise intensity increases, the body shifts from primarily using fat as a fuel source to using carbohydrates (glucose). ### Crossover Concept - - ### The "Shift" Refers To - - - - \*The **crossover concept** describes how your body changes its primary fuel source from fat to carbohydrates as you exercise harder. The **\"shift\"** refers to the point during exercise where this change occurs, influenced by factors like exercise intensity and fitness level.\* - **Epinephrine** (also known as adrenaline) - Epinephrine and other hormones glucagon, cortisol, growth hormone) stimulate lipolysis - Provides quick energy, maintains blood sugar levels, improves performance, spares glycogen stores, and stays hydrated. This helps them sustain their energy levels and enhance their endurance during long-lasting physical activities. - Glucose is necessary to burn fat. Glucose must be present in muscle to effectively oxidize FFAs and continue exercise. Oxaloacetate (OA) is recycled to facilitate acetyl CoA oxidation However, OA can degrade during exercise and can only be replaced by products of glucose (pyruvate) No glucose = no OA = no Krebs = no fat utilization \*glucose is required in the muscle to burn fat during long-duration exercise because it aids in the efficient oxidation of fatty acids, supports energy production, and ensures that the metabolic processes needed for fat utilization run smoothly.\* - -can serve as a source of energy during exercise -Lactate can also be used as a substrate to form glucose in the liver via **gluconeogenesis**, which then returns to skeletal muscle to burn fat -Lactate in muscle can be reconverted to pyruvate and oxidized (50-70%) - No. The body primarily uses carbohydrates and fats for energy, and protein is mainly important for the growth, repair, and maintenance of tissues. It serves as a backup energy source when other fuel stores are low. **Hormonal Response to Exercise---Chapter 5** - ### 1. Hormone as a Key: - ### 2. Target Cell as a Lock: - ### 3. Binding: - ### 4. Triggering a Response: - ### 5. Specificity: - \*A hormone knows which tissue to act upon by binding to specific receptors on target cells. Only cells with matching receptors will respond to the hormone, allowing for precise control over various bodily functions.\* - **Cortisol**: Adrenal glands (adrenal cortex) **Growth Hormone**: Pituitary gland (anterior pituitary) **Catecholamines (Epinephrine/Norepinephrine)**: Adrenal glands (adrenal medulla) **Insulin**: Pancreas (beta cells) **Glucagon**: Pancreas (alpha cells) - **Cortisol**: Increases during intense and prolonged exercise to help manage stress and energy metabolism. **Growth Hormone**: Increases, especially with high-intensity and resistance training, supporting muscle growth and recovery. **Catecholamines (Epinephrine/Norepinephrine)**: Increase significantly during intense exercise, enhancing energy availability and physiological responses. **Insulin**: Decreases during exercise to promote energy mobilization, with potential increases post-exercise for recovery. **Glucagon**: Increases during exercise to help maintain blood sugar levels by mobilizing energy stores. - - Maintaining blood glucose levels during exercise is crucial because it provides energy to your muscles, prevents fatigue, supports brain function, helps regulate hormones, and enhances overall performance. This is why athletes often monitor their carbohydrate intake and may use energy gels or drinks during long workouts. Also important to maintain blood glucose levels in order to prevent hypoglycemia During exercise, muscle contraction stimulates glucose entry into skeletal muscle = low blood glucose Low blood sugar stimulates the pancreas to release glucagon which promotes liver glycogenolysis = raising blood glucose Glucagon, cortisol, growth hormone, and epi all work together to raise blood glucose via: + Liver glycogenolysis + Gluconeogenesis + Muscle lipolysis - Inhibit glucose entry