Hses 260 Exam 4
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This 9 page Study Guide was uploaded by Areidbrydon on Monday March 7, 2016. The Study Guide belongs to HSES 260 at Kansas taught by Lowcock, Phillip in Fall 2015. Since its upload, it has received 35 views. For similar materials see Personal and Community Health in Physical Education at Kansas.
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Date Created: 03/07/16
HSES: 269 Introduction to Exercise Science Exam 4 Review Cardiovascular System Know the functions of the cardiovascular system o The cardiovascular system integrates the body as a unit. Provides active muscles with continuous stream of nutrients and oxygen O 2transport and delivery Removes metabolic byproducts o The maximal limits of aerobic energy transfer are set by: ATP synthesis capacity O 2transport and delivery o A pump The heart o A highpressure distribution circuit Arteries and arterioles o Exchange vessels Capillaries o A lowpressure collection and return circuit Veins and venules Know the function of blood vessels. Highpressure vessels, exchange vessels, and lowpressure vessels Know the functions of the left and right sides of the heart. o 2 hollow chambers (sides): Right heart Receives deoxygenated blood from systemic circulation Pumps blood to the lungs for aeration through pulmonary circulation Left heart Left ventricle is the most powerful of chambers and thus, the largest. Receives oxygenated blood from pulmonary veins Pumps blood to the systemic circulation o Ascending thoracic aorta o Interventricular septum – a thick, solid muscular wall that separates the right and left hearts Which side of the heart pumps blood with oxygen in to systemic circulation? o left What does exercise do to the size of the heart? o With vigorous exercise, the left ventricle size increases. Which compartments of the heart and vessels have valves? o Atrioventricular valves Right atrioventricular valve Tricuspid valve Left atrioventricular valve Mitral or bicuspid valve o Semilunar valves Valves that allow blood to exit the ventricles Actually exist in the arterial walls just outside the myocardium Prevent blood flow back into the ventricles o Right semilunar valve Pulmonary semilunar valve From right ventricle à pulmonary trunk à pulm veins o Left semilunar valve Aortic semilunar valve From left ventricle à ascending aorta à aortic arch… Know the functions of the atriums and ventricles o Atria – thinwalled, sacklike Receives and stores blood during ventricular contraction ~70% of blood returning to the atrium flows directly into the ventricles before the atrium contracts The simultaneous atrial contractions force remaining blood into the ventricles Almost immediately after atrial contraction, ventricles contract to propel blood into pulmonary or systemic circulation o Ventricles As ventricular pressure builds, the AV valves snap shut All 4 heart valves remain closed for about 0.020.06 seconds During this brief interval of rising ventricular tension: o Heart volume stays the same o Muscle fiber length remains unchanged o Called “Isovolumetric contraction period” When ventricular pressure exceeds arterial pressure, the semilunar valves are forced open Spiral and circular arrangements of bands of cardiac muscle “wrings out” blood from ventricles What is the skeletal muscle pump? o The Muscle Pump The rhythmic action of muscular activity and consequent compression of the vascular tree That is why many people faint when forced to stand upright without movement for extended periods Table tilt experiments: Person is strapped to table and held horizontally until HR and BP stabilize. If table is tilted upright: o Blood pools in the lower extremities (edema) o Hydrostatic pressure shift due to gravity o ↓ venous return, ↓ cardiac output, ↓ arterial blood pressure, ↓ cerebral blood flow o ↑ HR, ↑ blood mobilization from splanchnic region by upstream vasoconstriction, ↑ venoconstriction to counteract pooling Regulation of Cardiovascular System Know the parts of the Electrocardiogram o Depolarization waves P wave Atrial depolarization QRS complex Ventricular depolarization o Repolarization waves Atrial T wave Atrial repolarization Usually occurs during QRS; therefore, unnoticeable Ventricular T wave Ventricular repolarization Know the function of the SA node o Sinoatrial (SA) Node – pacemaker of the heart; right auricle Know what the percentage of blood flows directly from the atriums into the ventricles during atrium contraction and relaxation. o 70 – 75% of blood flows directly from the great veins into the ventricles before the atria contract. o Atria contraction causes an additional 25 – 30% ventricular filling. Therefore, atria serve as “primer” pumps that increase ventricular pumping up to 25 – 30%. Know what percentage of ventricular ejection occurs during the 1/3 and last 2/3 of systole. o 70% of ventricular ejection occurs during the first 1/3 systole. Know the influence of training on EDV, ESV, and EF. o Ventricular emptying (systole) When the heart contracts strongly, ESV can be as low as 10 – 20 mL. When large amounts of blood flow into the ventricles during diastole, EDV can be as high as 150 – 180 mL. Therefore, increases in SV (up to twice its resting value) can occur as a result of: Increasing EDV Decreasing ESV EndDiastolic Volume (EDV) During diastole, filling increases ventricular volume to 110 – 120 mL Stroke Volume Output (SV) During systole, ejection decreases ventricular volume by 70 mL EndSystolic Volume (ESV) Enddiastolic – stroke volume = endsystolic volume 40 – 50 mL Ejection fraction (EF) Stroke volume ÷ enddiastolic volume = ejection fraction ~ 60% Know the influence of training on stroke volume. o Determinant of cardiorespiratory endurance capacity at maximal rates of work o May increase with increasing rates of work up to intensities of 40% to 60% of max o May continue to increase up through maximal exercise intensity Understand cardiac output and how it is influenced by heart rate and stroke volume. o Q The amount of blood pumped by the heart per minute. Maximal Q reflects the functional capacity of the cardiovascular system to meet energy demands Dependent upon: Heart rate (HR) Stroke volume (SV) o The quantity of blood ejected from the heart with each beat. o Q (mL × min ) = HR (beats × min ) × SV (mL × beat ) 1 Pulmonary System Know the differences between pulmonary ventilation, external respiration, gas transport, and internal respiration. o Pulmonary ventilation – the process of ambient air moving into the lungs and exchanging gases. Lungs and External Respiration Function: Exchange of O 2nd CO be2ween cells and the environment Cells require O 2and must get rid of CO 2 Cells have no contact with atmosphere Cells must rely on external respiration of pulmonary function Nose/mouth à Trachea à Bronchi à Bronchioles à Alveoli o Pulmonary = Respiratory o 4 components of respiratory function: 1. Pulmonary ventilation: 1 Minute Ventilation = V E × min Air moves into the lungs from the atmosphere 2. External Respiration: Exchange of O 2nd CO be2ween lungs and blood 3. Gas Transport: From lungs to tissue through the circulation Actually a function of the circulorespiratory system 4. Internal Respiration: Exchange of O 2nd CO 2 Between blood and cells where tissue respiration is going on Know the function of alveoli o Site of gas exchange from external respiration o Extensive capillarization in alveoli walls o Very thin bloodgas barrier Alveoli membrane and capillary membrane Know the functions of the conduction and respiratory zones. o Conducting Zone Trachea, bronchi, bronchioles Passageway for air Humidifies and filters Protects lung tissue from drying out No gas exchange occurs o Respiratory Zone Gas exchange 300 million alveoli Surface area for diffusion=tennis court Alveolus and capillary only 1 cell thick Blood gas barrier only 2 cell layers wide Know the mechanics of ventilation o Air flow movement of air into and out of the lungs Occurs because of the intrapulmonary pressure changes Intrapulmonary pressure changes are the result of changes in the size of the thoracic cavity o “Negative Pressure Ventilation” à Intrapulmonic Pressure o Expiration at rest is a 2part process: Inspiratory muscle relaxation For expiration the diaphragm and intercostals relax passive Thoracic cavity returns to its’ original size This increases intrapulmonary pressure greater than ambient Air flows outward to the atmosphere Elastic recoil of the lung tissue o Expiration during exercise Expiratory muscles Abdominal group Internal intercostals Lower ribs and move them closer together Facilitates expirationactive Understand minute ventilation and the ventilatory breakpoint o V =E x Breathing rate (BR or RR) Minute Ventilation = tidal volume x respiratory rate o Ventilatory breakpoint – the point during intense exercise at which ventilation increases disproportionately to the oxygen consumption Skeletal Muscle Know the functions of tendons. o Transfers force from the muscle to the bone Know the functions of muscles. o Muscles pull on bones to allow movement (cannot push) o Maintain posture o Stabilize Joints o Pressure Alteration o Generate Heat Using energy creates heat Know the factors that influence maximum force generation. o Physiological crosssectional area o Length of the muscle o Velocity of shortening o Other factors… Prestretch: series elastic component Stimulus duration (stimulation frequency) Fatigue Fiber type Effectiveness of torque produced Know the types of muscle contraction. o Isometric – muscle remains the same length despite building tension o Isotonic – tension on muscle remains the same throughout the range of motion o Isokinetic – speed of the muscle motion remains the same despite changes in force amounts Understand the influence of pennation angle of strength. o The degree of pennation directly affects the number of sarcomeres per cross sectional muscle area Pennation results in a loss of force Pennation allows more sarcomeres to be packed into a given area Know the differences between type II and I fibers. o Slowtwitch fibers = type I fibers Slow twitch (ST) motor units selectively recruited during aerobic activity Prolonged exercise relies almost exclusively on ST fibers Limited remaining glycogen after 12 hours of exercise exists in the “unused” fasttwitch fibers Creates low amounts of force Receives large quantities of blood flow o Fasttwitch fibers = type II fibers “White” in color Generate force quickly (high power) Speed of shortening is 35 times faster than ST fibers Anaerobic activities; quick, forceful muscle actions Stopandgo activities, change of pace sports Know the lengthtension relationship. o The practical application of the sarcomere lengthtension curve: There are joint angles at which strength expression is greatest during isometric muscle contractions Know the muscle actions (extension, flexion, etc.). o Flexion – decreasing the angle of components of a limb (think of flexing your bicep) o Extension – increasing the angle of components of a limb (straightening your leg) o Adduction – brings a limb closer to the midline of the body (think of adding to your body) o Abduction – takes a limb away from the midline of the body o Supination – rotation of the forearm so palms face up/out (think of the typical barbell bicep curl exercise) o Pronation – rotation of the forearm so palms face down/back o Rotation – movement of limb in circular motion Understand muscular power and at what velocities power is the greatest. o Power = how quickly or slowly work is done. Units: Watts (W) 1 W = 1 J/s o Muscle power increases as contraction velocity increases, to a point… At slow speeds, power output is low At faster speeds, power output is higher Maximum power output occurs at approximately ½ of the maximum shortening velocity. After this point, power decreases as velocity increases Maximum power output occurs at a velocity approximately one half the muscle’s maximum contraction velocity. Understand the adaptations that muscle undergoes during training as discussed in class. Nervous System What is a motor unit? o Single motor neuron and all the muscle fibers it innervates. Motor neuron may innervate <20 fibers or >1000 fibers! Ratio of muscle fibers to motor neuron indicates the degree of control o Large motor units, many muscle fibers per neuron Strong, gross muscle force production, but little precise control Example: gastrocnemius, biceps brachii o Smaller motor units, few muscle fibers per neuron Weak contraction strength, but very precise control Example: external occular muscles, obicularis occuli What is the innervation zone? o Innervation zone locations Location where nerve terminations and muscle fibers are connected. The placement and number of IZs are dependent on the structure and function of muscle. What influence does resistance and endurance training have on motor unit control behaviors? o Endurance trained individuals rely more so on the lower threshold motor units (MUs) which produced greater firing rates since these MUs do not fatigue quickly. o Resistance trained individuals rely on the higher threshold MUs, which display lower firing rates since these are fast fatiguing. Understand the two ways we control movement (i.e., recruitment vs. rate coding). o Recruitment – control the number of active motor units o Rate coding – control the firing rates of the active motor units What are the functions of muscle spindles? o Proprioceptor that detects changes in muscle length o “Intrafusal” fibers à parallel to regular, extrafusals When muscle is stretched, these fibers lengthen and send afferent signals to CNS Type Ia afferent fibers – direct synapse with motor neuron Causes the stretched muscle to contract When muscle has lengthened (or ceases lengthening), γefferents contract the spindles to “reset” them What is the stretch reflex? o Protective function to prevent overstretching o Reflexes – involuntary responses from sensory input with no involvement from higherorder CNS Can be stimulatory or inhibitory
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