Respiration and Nervous System

Respiration

• The respiratory zone includes the respiratory bronchioles
• The internal intercostals are engaged during forced expiration
• Tidal volume is the lung volume recorded when a person sits and breathes quietly into a spirometer
• Vital capacity is recorded when a person breathes in as deeply as they can and then forcefully exhales as much as possible into a spirometer
• Gas partial pressure is critical in determining the rate of pulmonary diffusion
• Dalton's law states that the partial pressures of nitrogen, oxygen, and carbon dioxide add up to atmospheric pressure
• Lower pH during exercise induces the Bohr effect
• Carbonic acid/bicarbonate transport in blood contributes to acid-base balance

Nervous System

• In a resting neuron, potassium ion gates are open
• The sodium-potassium ATPase pump maintains resting membrane potential at rest
• Inhibitory postsynaptic potentials (IPSPs) lead to hyperpolarization
• Sodium is most important for depolarization as the membrane becomes more permeable to this ion
• During depolarization, the membrane potential voltage gets closer to 0
• The axon hillock region of the nerve cell integrates all incoming EPSPs and IPSPs
• Threshold is the membrane potential at which an action potential will definitely occur
• Potassium is most important for repolarization as the membrane becomes more permeable to this ion
• During the relative refractory period, a neuron can be stimulated only by a stronger-than-normal stimulus
• Fastest impulses travel on axons that are myelinated and large
• If the net effect of all graded potentials is hyperpolarization, nothing will occur
• An afferent neuron sends impulses from the body to the brain
• The myelin sheath is made of Schwann cells, allows for saltatory conduction and insulates the nerve cell
• The cerebellum is the region of the brain affected if someone is having trouble passing a roadside sobriety test due to a lack of coordination
• The hypothalamus oversees homeostatic control of blood pressure, heart rate, breathing, and body temperature in the diencephalon
• The highest levels of thought, interpretation, planning, analysis, cognition, and perception occur in the cerebral (gray) cortex
• General sensory input from muscles and joints is processed in the parietal lobe
• The primary motor cortex is where the decision to voluntarily move your arm comes from
• Joint kinesthetic receptors would tell the brain that the elbow was fully extended but is now bending quickly
• The somatic nervous system activates muscles in the legs for running
• Pacinian corpuscles and Meissner's corpuscles send sensory information to the brain regarding the skin
• Sensory impulses that result in the subconscious control of posture are integrated in the brain stem
• A motor unit with a neuron-fiber ratio of 1:20 might be found innervating the tensor tympani muscle of the eardrum
• High-intensity interval (HIIT) training increases the motor unit discharge rate
• Motor or efferent nerves carry nerve impulses from the brain to the periphery
• Receptors are nervous system structures responsible for sensing a stimulus
• Dendrites receive nerve impulses from other neurons
• The autonomic division of the nervous system controls visceral or internal activity
• The fatty insulation that often surrounds axons is called myelin sheath
• Resting membrane potential in a neuron is -70 mV
• Cells responsible for insulating axons by producing myelin in the peripheral nervous system are called Schwann cells
• The periodic gaps between myelin sheaths on a neuron are called Nodes of Ranvier
• Chemicals that transfer an electrical signal from one cell to another are called neurotransmitters
• The basic cellular unit of the nervous system is a neuron
• The tiny bulbs at the very end of an axon are called axon terminal/synaptic knobs
• A localized change in the membrane potential of a neuron is called a threshold
• The membrane potential at which an action potential will definitely occur is called the threshold
• A neuron cannot respond to another neural stimulus during the absolute refractory period
• A synapse is the junction between two neurons where an action potential is passed from the presynaptic cell to the postsynaptic cell
• A rapid, substantial, and inevitable depolarization of a neuron is an action potential
• The basal ganglia are clusters of cell bodies in the cerebrum that help initiate repetitive movements, like walking and running
• The (region of the brain) helps refine movements and compares intended movements to actual movements
• Endorphins may modulate pain during exercise by acting on the brain stem's analgesia system
• The special collection of neurons in the brain stem, helps coordinate skeletal muscle function, maintain muscle tone, and control heart and breathing function
• Golgi tendon organs are sensory receptors that are found in tendons and are responsible for sensing muscle tension
• The sympathetic nervous system controls what is commonly known as the fight-or-flight response
• Recovery of normal heart rate, airway diameter, and arterial diameter after exercise occurs through the parasympathetic nervous system
• Threshold voltage in a neuron is typically -40 mV (False)
• Saltatory conduction occurs in myelinated axons (True)
• In a resting neuron, the intracellular environment is more negative compared to the extracellular environment (True)
• An excitatory postsynaptic potential depolarizes the postsynaptic membrane (True)
• At a synapse, the postsynaptic cell sends neurotransmitters to the presynaptic cell (False)
• The sympathetic nervous system is critical for appropriate responses to exercise (True)
• Motor units can contain multiple types of muscle fibers (True)
• As one ages, maximal strength decreases at a faster rate than rapid strength (False)

Endocrine System

• The endocrine system responds more slowly but has longer-lasting effects than the nervous system
• A key characteristic of steroid hormones is they are lipid soluble
• Nonsteroid hormones are characteristically amino acid/protein-based
• A key characteristic of prostaglandins is that they exert their effects locally
• For a given plasma concentration, hormone effectiveness can be altered by the number of cell receptors
• The anterior pituitary is controlled by hypothalamic hormones
• During prolonged exercise, T3 decreases, while T4 plateaus
• Exercising muscle used glucose from muscle glycogenolysis preferentially
• An increase in plasma osmolality is the stimulus for the release of aldosterone

Principles of Training

• If the rate of oxidative production of ATP is low, then aerobic power is low
• A low responder is someone who experiences little or no change after a change in training regimen
• Intensity and frequency are the two factors most commonly manipulated in training for increased performance
• Resistance programs aimed at improving strength should involve concentric and eccentric training
• Static-contraction resistance training is most effective for building strength during rehabilitation
• Isokinetic training ensures that speed remains constant
• Use a heart rate monitor to establish the intensity of a distance interval
• LSD training aims for 70 % maximal heart rate for long distances
• One mechanism by which HIIT delays fatigue is by reducing the accumulation of hydrogen ions in the muscle
• Training for just 3 minutes a week can improve insulin sensitivity

Adaptations to Resistance Training

• The neuromuscular system is one of the most responsive systems to training
• Muscles increase the rate of force development when motor units contract more synchronously
• Eccentric training is critical in developing fiber hypertrophy
• The most common fiber type alteration with heavy resistance training is more type IIa, less type I
• In general, whole-muscle hypertrophy in humans most likely results from mostly fiber hypertrophy with some fiber hyperplasia
• Strength losses after immobilization are greatest during the first week
• The recommended amount of protein to consume following resistance exercise is 20-25 g
• Neural adaptations are the primary cause of strength gains in older adults
• Resistance training techniques designed for men are equally appropriate for women's training
• Resistance training is especially helpful in elderly populations because it can help prevent falls
• The ideal time of day to perform resistance training and ingest protein to increase muscle hypertrophy is afternoon (2 p.m. to 5 p.m.)

Adaptations to Aerobic/Anaerobic Training

• VO2max has been reached if the intensity of a single bout of aerobic exercise continues to increase, but VO2max plateaus or decreases slightly
• A sign of enhanced submaximal endurance capacity is decreased submaximal heart rate
• The increase in SV after aerobic training is because preload and contractility increase, and afterload decreases
• After aerobic training, systolic BP increases and diastolic BP decreases
• Tissue O2 extraction increases the (a-v)O2 difference after aerobic training
• Chronic endurance training results in type I fiber hypertrophy
• Oxygen diffusion from capillary to mitochondria, is a major factor in muscle that limits further increases in VO2max
• After chronic endurance training, RER during submaximal exercise indicates that the body is depending more on fat and less on carbohydrate for fuel
• Training status plays the biggest role in determining VO2max
• Anaerobic training leads to increased glycolytic and ATP-PCr production of ATP

Exercise in Heat and Cold

• The primary source of heat loss during exercise in the heat is evaporation
• When an athlete is exercising in hot and humid weather, core temperature will increase faster
• The critical temperature theory suggests that exercise is shut down when a given core temperature is reached
• Endurance training causes sweat glands to decrease the electrolyte content of sweat secretion
• Exercise is shut down when a given core temperature is reached, according to the critical temperature theory
• Training causes sweat glands to decrease the electrolyte content of sweat secretion
• Heatstroke is most effectively treated using whole-body immersion in an ice bath
• Acclimation is best achieved through exercising at low-to-moderate intensity in the heat for 1 h/day for 9 to 14 days
• Convective heat loss increases as windchill becomes greater
• During exercise in the cold, the primary metabolic substrate is glucose/glycogen due to increased circulating catecholamines
• If muscle glycogen and blood glucose both start to run low during exercise in the cold, there will be shivering
• The ability of the hypothalamus to regulate body temperature is compromised when core temperature falls below 34.5 °C (94.1 °F)
• During prolonged exercise in the heat, an increase in heart rate is due to dehydration

Exercise at Altitude

• Water vapor pressure is lower at altitude because cold air cannot hold very much water
• During the early phase of altitude exposure, muscle oxygen exchange is diminished due to lower arterial PO2
• During acute altitude exposures, maximal-intensity aerobic exercise is characterized by diminished maximal cardiac output
• Red blood cell concentration increases within hours of reaching altitude due to decreased plasma volume.
• VO2max starts to decline at approximately 500 m
• The oxidative metabolic system is most affected by altitude
• Increased capillary density is not a major contributing factor to muscle loss at high altitude
• Livining at altitude and training at sea level will confer maximal improvements in performance
• Enhanced VO2max is not a consequence of live high, train high
• Inadequate ventilatory response seems to put people at the highest risk for developing acute mountain sickness
• If competing at altitude, arriving 2 weeks before the event is recommended in order to acclimatize