exercise which increases heart rate/breathing rate for at least 20 mins, improves function and use of oxygen
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recommended exercise
moderate activity 150 mins a week
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adrenaline
causes initial increase in heart rate when you start exercising
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divert blood flow
adrenaline causes vasodilation of arterioles in muscles and skin and vasoconstriction of arterioles in gut and non essential organs
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nitric acid
secreted when oxygen levels drop in muscles causing vasodilation
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stroke volume
increases as more blood returns to heart, therefore increases cardiac output
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breathing
rate and depth increases allowing more carbon dioxide to be removed
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carbon dioxide concentration increase
reacts with water forming carbonic acid which lowers blood pH
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chemoreceptors
located in brain and aortic arch, they detect falling pH and trigger in increase in breathing via sympathetic nervous system
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training
repeated short bouts of exercise over long term allowing the body to adapt to it
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systems which adapt to long term exercise
circulatory system, respiratory system, muscular system
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lower heart rate
effect of long term exercise as more blood returns to heart (vein compression), ventricles stretched more and contract more forcefully (sterlings law), ventricle muscle increases, higher stroke volume
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recovery time
Time for heart to return to resting state
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skeletal mucles
increase in cross sectional area, increase in number and size of mitochondria, more blood capillaries, more glycogen and myoglobin
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aerobic fitness
how efficiently oxygen is used
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contribute to aerobic fitness
age, gender, smoking, exercise program, nutrition
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FITT factors
frequency, intensity type and intensity/duration of exercise
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frequency of exercise
3-6 per week, strength and resilience training training for less to allow recovery
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intensity of exercise
the effort put into et eg speed, distance, weight. moderate to high causes heart to increase to heart max
shorter but more frequent or longer but less frequent, maintain elevated heart rate fir 20mins+
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VO2 max
maximum rate which oxygen can be taken in, transported and utilised in exercise
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VO2 max expressed
absolute rate eg litres of oxygen per min dm3 min-1
or relative rate eg millimetres of oxygen per kilogram of body mass per minute ml kg-1 min-1
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measure VO2 max
undertake graded exercise whilst ventilation oxygen and CO2 concentration of inhaled and exhaled air is measured, its reached when O2 consumption remains the same despite intensity increasing
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precautions of carrying out VO2 max test
risk assessment of to determine existing health conditions, death suitable clothing, check equipment is in working order
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measure aerobic fitness
indicated by time for heart rate to return to resting after exercise
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Harvard step test
used to assess effect of FITT factors on aerobic fitness and indicate VO2 max
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1, 5, 3, 4, 2, 6
order statements
1. using a 30-50cm high step, step up placing both feet on the step and step down placing both feet on floor 2. Convert pulse rates to beats per minute and add together 3. Wait 1 minute after stepping then measure pulse rate 4. Repeat pulse rate measurement at 2 minutes and 3 minutes after stepping 5. Each step cycle should take 2s and stepping is carried out for 300s 6. Calculate a score using the equation 100 x 300 / total beats per minute since 300s was the duration of stepping
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measure pulse rate
use radial artery (wrist) or carotid artery (neck), use 2 fingers (not thumb) count for 30 seconds and multiply
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measure effect of exercise
measure heart rate/pulse rate before, during and after, breathing rate, blood pressure, reaction times cognitive tasks
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ethical and health safety issues for deciding someone can precipitate
give informed consent and know any potential health issues
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factors to control when investigating activity
age, time of day, type and duration of exercise, sex, weight, height, fitness, BMI
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oxygen deficit
when oxygen supply doens’t meet demand
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excessive post-exercise oxygen consumption (EPOC)
period of increased oxygen consumption following vigorous exercise
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oxygen dept
additional oxygen required to metabolise lactate
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processes requiring oxygen after exercise
re-oxygenation of haemoglobin and myoglobin
oxidising lactate to pyruvate
regeneration of ATP and creatine phosphate
replenishing glycogen stores In muscle
meet increased metabolism rate due too been warmer and increased heart rate
cell repair
balancing hormones
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oxygen deficit builds up at a start of exercise
takes time for heart rate and breathing rate to increase to meet demand
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EPOC decreases with increased aerobic fitness
due to increased VO2 max due to increased stoke volume, more myoglobin and creatine phosphate
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carbohydrate loading
aims to increase glycogen stores which can be hydrolysed to glucose for respiration
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benefit from carbohydrate loading
endurance athletes not sprinters as it allows muscles to work for longer
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carbohydrate loading regime
carbodepletion- less carbohydrates and more proteins/lipids from 10 days prior
carbohydrate loading- high carbohydrate diet diet 2-3 days prior to event
recovery- eat carbohydrates to replenish glycogen stores
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athletic performance depends on
oxygen availability
carbohydrate availability
mass of muscles §
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blood doping
artificial increase in red blood cell concentration
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methods of blood doping
use recombinant erythropoietin (RhEPO)
autologous blood doping
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erythropoietin
protein secreted by cells surrounding capillaries in renal correct of kidney in response to low oxygen levels or reduced blood volume
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train at high altitude
low partial pressure of oxygen stimulates production of erythropoietin which increases number of red blood cells- legal
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inject recombinant erythropoietin
artificially increase number of red blood cells and therefore oxygen by a substance produced from genetically modified bacteria. illegal and may lead to kidney failure and increased chance of thrombosis
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autologous blood doping
remove 1 dm3 of blood, which their body replenishes the inject their packed blood cells back into their body
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anabolic
synthesise complex molecules from simple molecules
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group of macromolecules with steroids
lipids
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steroids synthesised form
cholesterol
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steroids are able to pass through cell surface
due to them been non polar lipids
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steroids cause
transcription and synthesis of new muscle protein
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transcription factor
molecule which binds to DNA and determines which genes are expressed
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anabolic steroids
eg nandrolone and stanozolol, are artificially produced and injected into muscles to music action of hormones like testosterone which increase protein synthesis
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anabolic steroids effet
promote growth and repair allowing more muscle building, train for longer and recover faster. also increase erythrocyte production and therefore VO2 max
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why anabolic steroids are banned
enhance perforce giving an unfair advantage, health risks
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health risks of anabolic steroids
altered behaviour eg aggression and mood swings
liver dammage
infertility and altered sexual characteristics
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creatine phosphate
legal performance enhancer found in many foods and naturally synthesised by the body
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creatine phosphate
can lose its phosphate group to phosphorylate ADP to ATP
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respiratory pigments
haemoglobin
myoglobin
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haemoglobin
found in erythrocytes to transport oxygen
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myoglobin
found in muscle tissue to store oxygen
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haemoglobin structure
quaternary protein containing 4 polypeptide chains with a haem prosthetic group (Fe2+ which binds to oxygen)
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saturated
when 4 oxygen bind to haemoglobin
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associate
when oxygen bind to haemoglobin
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dissociation
release of oxygen from haemoglobin
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oxygen realsed
haemoglobin response to increase of carbon dioxide and drop in oxygen in respiring tissues
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myoglobin structure
a tertiary protein containing one ham group
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haemoglobin function
carry oxygen (oxyghaemoglobin HbO8)
carry carbon dioxide (carboaminohaemoglobin)
act as a buffer
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partial pressure of oxygen
pO2 is a measure of relative pressure oxygen contributes to a mixture of gases
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lungs
area with high partial pressure where haemoglobin becomes fully saturated
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respiring tissues
low partial pressure where haemoglobin becomes half saturated
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s shaped curve
oxygen dissociation curve, due to co-operative binding, once one oxygen binds it is easier for more to, hard to achieve 100 saturation
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myoglobin oxygen affinity
higher affinity for oxygen than Hb so only releases oxygen at low pO2
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fetal haemoglobin
able to bind to oxygen at a lower affinity where adult haemoglobin dissociates. this is due to its higher affinity for oxygen
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fetal haemoglobin
quaternary structure made of 2 alpha and 2 gamma globin chains
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adult haemoglobin
quaternary structure made of 2 alpha and 2 beta chains
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carbon dioxide transport in blood
5% dissolves in plasma
10% combines with Hb to form carbaminohaemoglobin
85% transported as HCO3- in plasma
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carbonic anhydrase
enzyme which catalyses reaction of CO2 and water to form carbonic acid. within red blood cells
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carbonic acid
produced from CO2 and dissociates to H+ and hydrogencarbonate (HCO3)-
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chloride ions
inward movement of ions to balance outward movement of hydrogencarbonate into plasma from red blood cells
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H+ ions
cause oxyhemoglobin to dissociate and release oxygen, due to it binding and forming haemoglobinic acid, this prevents a change in pH
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greater affinity for oxygen
dissociation curve shifts to left
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lower affinity for oxygen
dissociation curve shifts to right
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Bohr effect
increase in CO2 causes dissociation curve to shift to right, due to more H+ ions causing dissociation of oxygen
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pH
decrease causes dissociation curve to shift to right, due to anaerobic respiration producing lactic acid and therefore H+
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temperature
raise causes dissociation curve to shift to right, due to it effecting H and ionic bonds in haemoglobin and association between oxygen and haemoglobin
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types of muscle
cardiac muscle
skeletal muscle
smooth muscle
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smooth muscle
involuntary, found in walls of arteries and intestines and controls blood flow, moves food and controls pupil size, contracts slowly without fatigue, spindle unstriped fibre appearance.
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cardiac muscle
forms part of heart, contracts continuously to pump blood, connected to intercalated disks to allow transmission of action potential, some are myogenic, contracts rhythmically without fatigue, striated
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skeletal muscle
voluntary muscle, attached to skeleton via tendons, contracts to move bones at joints, striated, contracts rapidly and powerfully but fatigues quickly
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cause of striped muscles
due arrangement of protein filaments in myofibrils
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thick protein filamnet
composed of myosin, surrounded by 6 other filaments
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think protein filament
composed of actin, troponin and tropomyosin, around 1 filament
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z line
are the thin filaments anchor to with the distance between been called a sarcomere, move closer together with muscle contraction
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sarcomere
distance between 2 z lines, approximately 2.5µm in length when relaxed, and shortens when muscles contract as the filaments slide past each other,
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G actin
2 chains of globular subunits twisted together
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tropomyosin
hides a myosin binding site on the actin subunits
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troponin
found at intervals with 3 subunits, one binds to tropomyosin, one to actin, one to Ca2+