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Flashcards in the body and exercise Deck (11):
1

describe the aerobic energy system

- prolonged exercise (marathon, not high intensity)
- lower intensity (slow-twitch muscle fibres)
- requires oxygen (mitochondria)
- glucose and glycogen (liver), adrenalin causes release of glycogen into blood from the liver
- fuels stored in muscle, adipose tissue and liver
- the key is hormonal adjustment
- recovery time (produces ATP slowly)
- non suitable for intense exercise
- red muscle fibres (many capillaries, oxygen), common in thigh / leg, harder to increase size of fibres

2

describe the lactic energy / glycolytic system (anaerobic)

- do not rely on oxygen
- the by product is lactic acid
- an accumulation of H+ causes muscular fatigue
- energy lasts less than 2 min (fast contraction fast fatigue)
- 400m run, 100m swim
- recovery time ranges from 20 sec (distribution of energy) -3 min
- active recovery (lactic acid - liver - glucose - glycogen)
- white muscle fibres (less capillaries)

3

describe the ATP-CP energy system (anaerobic)

- do not rely on oxygen
- short duration, quick movement
- high intensity in short period of time (sprinters)
- great intensity (fast twitch muscle fibres)
- creatine phosphate (donates P to ADP) and glycogen (glucose) from muscle
- white muscle fibres (less capillaries) - common in arms, chest and shoulders, easier to increase size of fibres

4

how does the body respond / adapt to exercise

- muscular (contraction) and skeletal (movement)
- cardiovascular (increase HR, BP, HB)
- respiratory (increase in gas exchange)
- nervous (control muscular fibres)
- chemical (hormones - adrenaline)
- all respond differently

5

how does the muscular system respond / adapt

- muscle fibres are elastic and can change
- energy storage: increase in glycogen storage)
- hypertrophy: increase in volume of muscle fibres - especially white)
- fibre type: red vs white = genetic, ability to switch)
- motor control: connection between neuronal fibres and muscular fibres)

6

how does the skeletal system respond / adapt

- less immediate than muscular response
- bone density = months, minimise the effects of bone related disorders
- constant low intensity exercise = increase density of bones (decrease arthritis)
- bony prominences as a result of exercise
- haglund’s deformity: enlargement of heel, runners, wearing tight shoes (change shape of bone)

7

how does the respiratory system respond / adapt

- increase ventilation, accessory respiratory muscles (15% cardiac output = respiratory muscles)
- reduction of work required to breath, adrenaline (broncho dilation), fatigue resistant motor units, coordinated skeletal muscle (less energy consumed)
- 3 neural factors = increased ventilation
- psychological stimuli: anticipation
- simultaneous cortical motor activation: skeletal muscles / respiratory centres
- excitatory impulse: proprioceptors in moving muscle
- rest = 5L air / min (1/3 capillaries functioning, 2/3 dead space)
- exercise = >15L air / min, no dead space (3/3 functioning), maximum gas exchange

8

how does the cardiovascular system respond / adapt

- HR, cardiac output (CO), BP = increase
- CO: amount of blood pumped every minute, increase stroke volume (blood pumped each HB) / heart rate (bpm)
- steady-state HR: rises linearly with work rate over range from rest to VO2max (ml/kg/min)
- dynamic: running cycling, slight increase SBP, DBP scarcely alters
- isometric: weightlifting, huge increase SBP and DBP
- difference: compression of intramuscular arteries presents vasodilation / increased BF = low O2 = high lactic acid = stimulation of chemoreceptors = excite SNS
- heart: adrenaline / endothelial secretion of nitric oxide / prostacyclin (vasodilators) = increase CO, coronary flow, endothelial cell shear stress, endothelial dependent vasodilation and SNS

9

how does the left ventricle adapt

- endurance: cardio, increase internal volume of ventricle, wall thickness is constant, less BPM, increase SV
- strength: short, high intensity, increase in total volume but internal volume remains constant (increase thickness of wall - must beat against higher pressure)

10

how does the nervous system respond / adapt

- nervous fibres connected with smooth muscle cells in walls of capillaries (can change amount of blood in specific organs depending on activity of our body)
- changes in blood flow to organs based on what requires energy during exercise
- no change in brain
- dramatic decrease in intestine
- dramatic increase in skeletal muscle and heart

11

how does the coordination of skeletal muscle contraction occur

coordination:
- common movement = years of training
- walking / swimming = complex (coordination of entire body)
sympathetic influences:
- SA node: increase HR (less blood in venous, increase demand for arterial),
SV (increase contraction)
- dilates bronchi
- inhibition of urination and digestion (intestine movement)
- stimulates glucose release (adrenaline = liver release glycogen used by)
regulation of fluid volume:
- sweat = 1.8 L / hour, 10% of sweat = plasma volume (dense = embolism)
- fluid lost during exercise (sweat, respiration) = less urine
hormones:
- ADH, aldosterone and renin (reduce production of urine increase fluid retainment)