SPORT AND EXERCISE PHYSIOLOGY HANDBOOK

(ASSIGNMENT EVIDENCE)

MODULE: SPORT AND EXERCISE PHYSIOLOGY

COURSE: BND SPORT AND EXERCISE SCIENCES (YEAR 1)

TUTOR: JULIE PLANT

STUDENT NUMBER: FCS251761

STUDENT NAME: Letitia Price

THE INITIAL RESPONSES OF THE BODY TO EXERCISE

1. DESCRIBE THE INITIAL CARDIOVASCULAR RESPONSES TO EXERCISE

        The initial responses to exercise are:

  • The heart rate increases.
  • Anticipatory heart rise occurs.
  • Increase in carbon dioxide in the body.
  • Increase of lactic acid in the body.
  • Body temperature increases.
  • Stroke volume increases.

2. EXPLAIN THESE CARDIOVASCULAR RESPONSES, SUGGESTING WHY THEY OCCUR

The cardiovascular system increases the rate of the heart to provide the muscles adequate amounts of nutrients and oxygen, as without these two components they could not function, the heart rate is the amount of time the heart beats or contracts to produce blood flow.

Also the increased heart rate increases the removal of waste products because the blood pressure has been increased; the blood pressure is the speed of which blood is passing through vessels.

Before any activity your anticipatory rise increases because when your brain thinks about exercising it stimulates the sympathetic nervous system which releases adrenalin, average persons anticipatory heart rate would be 10-15 more heart beats than their resting heart rate.

        The increase of carbon dioxide and lactic acid is because as we inhale more oxygen we are also producing more carbon dioxide therefore there will be more carbon dioxide levels in our blood stream.

        The increase of lactic acid is because during the first 10 seconds of an activity our bodies cannot adapt quickly enough to use oxygen to provide enough energy; therefore our bloodstream provides lactic acid into the muscles however this can cause serious fatigue.

The increase of carbon dioxide and lactic acid is detected by cells called chemoreceptor’s these detect changes in chemical environment, therefore this can inform the brain so it can transfer a message to the body to adapt accordingly.

        When chemoreceptor’s are active this can stimulate the sympathetic nervous system this increases the adrenalin this then increases the heart rate. Normally an athlete’s heart rate can increase up to three times within a minute of starting exercise.        

        Bodily temperature increases because as the blood pressure increases this enables the muscles to contract more creating more heat, and because of this bodily temperature increase it increases the speed of the conduction of nerve impulses across the heart.

        Stroke volume is the outcome from Cardiac outcome, a stroke volume can be around 70-90 millilitres, however it can depend on how fit you are, the fitter you are the larger stroke volume you have, generally males have a larger stroke volume than females as their hearts are naturally stronger and muscular. 

3. USING GRAPHS, TABLES, RESEARCH, EXAMPLES AND PRACTICAL EXPERIENCES TO SUPPORT YOUR ANSWER, ANALYSE THE INITIAL CARDIOVASCULAR RESPONSES TO EXERCISE

        Everyone’s cardio vascular response to exercise is very different for an example if you analyse a top athlete’s initial response to exercise you would find it would differ to someone who is obese. This is because an athletes heart rate initially  in the first minute of exercise increase by double their resting heart rate, this is because it is used to being training and is preparing the body for exercise. However for an obese person their initial responses to exercise would be their body temperature would increase massively this is due to their body fat trapping the heat within their muscles therefore their muscles require more energy to function correctly as they are having to contract under much more heat. An obese person’s stroke volume would be very little, therefore their heart is unable to supply their body quick enough with oxygen resulting in quicker fatigue.

        We had a small group carry out an aerobic exercise whereby they had to run on a treadmill for 1 minute, 2 minutes and 3 minutes with a 30 second interval between each run we used these results to view a persons heart rate and blood pressure after the exercise and we had found for every person their heart rate increased by approximately ½ at least, this displays an instant response to exercise because from viewing the aerobic response graph you can clearly see that the heart rate increased rapidly at the second minute, this is because all of the components in cardio vascular system are preparing themselves for an intense work out therefore they have to supply the body quickly.

4. DESCRIBE THE INITIAL RESPIRATORY RESPONSES TO EXERCISE

        The initial responses to Respiratory are:

  • Pulmonary ventilation per a minute would increase; this is the amount of air we breathe in and out per minute.
  • Tidal volume increases, this is the volume or amount of air breathed in and out during one breath
  • Intercostal muscle contractions increase.

5. EXPLAIN THESE RESPIRATORY RESPONSES, SUGGESTING WHY THEY OCCUR.

When we begin exercise our pulmonary ventilation per a minute increases due to the frequency of breaths per a minute is increased and also the tidal volume increases, this then requires the body’s pulmonary ventilation to increase, because as our muscles require more and more oxygen the need to breathe it in and out is essential.

        Due to the tidal volume increase this would increase the amount of air we need to breathe out; this is the body’s response at first to reducing the amount of carbon dioxide within the body. To calculate Pulmonary Ventilation the equation is:

VE = Frequency x Tidal Volume

At rest it is estimated that the frequency of the breathing rate is around 12 breaths per a minute and the average tidal volume is 0.5l however this does heavily depend on age, gender and size of the person.

So to calculate the pulmonary ventilation it would look like so:

VE = 12 X 0.5

= 6 litres

        As exercise is begun the body requires more oxygen to be entering the body for it to be used in the aid of producing energy, at the start of exercise this increased oxygen demand occurs by breathing at an increased rate and inhaling more air and exhaling more air during each breath.

        When breathing we require our intercostal muscles to contract, they are located between the ribs, they assist within inhaling and exhaling this is because they assist within the expansion of the ribs to allow the lungs to either become larger to allow more air in or either becomes smaller to ensure the largest amount of air is exhaled. During the initial stages of exercise the intercostal muscles contraction rate would automatically increase vigorously, this is because the muscles have to react quick enough to the demand of the lungs are forcing upon them to expand and deflate the ribs structure.

6. USING GRAPHS, TABLES, EXAMPLES AND PRACTICAL EXPERIENCES TO SUPPORT YOUR ANSWER, ANALYSE THE INITIAL RESPIRATORY RESPONSES TO EXERCISE.

For this topic a group of candidates carried out an experiment using a vital capacity bag to calculate the amount of breaths an individual carried out in a minute at rest, and then during activity and then after activity and the table looked like so:

From looking at this table it is evident that the breathing rate increased rapidly during exercise, by 37 breaths however after activity the breathing rate decreased down to 28 breaths, this is displaying that the body is not requiring as much oxygen, and this is also an indication that this client had high fitness levels, because their body only required 28 breaths and the air they were inhaling was enough to recover from the exercise.

        From looking at the tidal volume, this also increased as expected by 0.48 L this is an indication that the athlete required large amounts of oxygen per each breath, this also explains why the breath rate was particularly low, because the amount of air being inhaled and exhaled was 0.92l, therefore the body’s initial response after the exercise was to inhale as much air as possible to reduce the breathing rate, because then this way the more air going into the body the more air there is that can be utilised.

7. DESCRIBE THE INITIAL NEUROMUSCULAR RESPONSES TO EXERCISE

        The initial neuromuscular responses to exercise are:

  • Nerve impulses from the brain and muscles increase.
  • Muscle contractions increase
  • Action potential increases
  • Increase in Acetylcholine diffusion.
  • Increase in the excitatory post-synaptic action potential.
  • An increase in the enzyme cholinesterase occurs.

8. EXPLAIN THESE NEUROMUSCULAR RESPONSES. ALSO SUGGEST WHY THEY OCCUR

When our bodies require us to produce movement our brains have to provide our muscles with the signals to carry out the movement, this type of communication between the brain and the muscle is known as nerve impulses, these nerve pulses are electrical currents that travel from the central nervous system also known as the CNS through nerves and then to the desired muscle tissues, which the final result produces movement. Therefore initially when we begin exercise there are more muscles involved which require nerve impulses from the brain to create the movement, and these have to be sent within split seconds, this is why the nerve impulses coming from the brain increase, because not only do they have to send the normal resting nerve impulses but they also have to send nerve impulses to the desired organs or parts of the body which now have had an increase demand of contractions. For example the hearts contractions initially in exercise increase by up to 10-20 beats per a minute therefore to carry out this increased heart contractions more nerve impulses are needed to be sent.

        Also when these increased signals are sent, initially any muscular contractions would also be on the incline because at rest or relaxation all muscles still need to contract otherwise the body would just collapse or “flop”, therefore slight signals are sent to these muscles to remained contracted, however as soon as exercise begins the brain sends increased amount of nerve impulses to contract the muscles at a quicker rate, this is why it is said that weight resistant training can be more beneficial to loose weight, because as the muscle contractions are quicker they require more and more energy.

        The signal sent from the CNS to the muscles is what’s called an “Action Potential”, as the signal is sent to the motor neurones the motor neurones signal a contraction to the muscle fibres. The Action Potential increases because the signals sent from the brain to the CNS are an increased amount of signals therefore the CNS has to provide more Action Potentials to assure that the motor neurones signal quickly enough to the muscle fibres to produce the desired movements.

        Acetylcholine diffusion occurs across the gap between the nerve and the muscle, this produces an electrical signal which is known as the Excitatory post-synaptic action potential, as initial exercise begins the diffusion of Acetylcholine is going to increase because as the muscle requires to contract more to produce more movement this requires more electrical signals to be sent to the muscles to produce this contraction, therefore Acetylcholine needs to diffuse more quickly to ensure that the Excitatory post-synaptic action potential occurs, otherwise if this signal is not big enough the muscle tissues will fail to contract sufficiently.

        In result of the increased Acetylcholine production, there is an enzyme known as Cholinesterase, this type of enzyme has the characteristics to break down the Acetylcholine, this is essential that Acetylcholine is broken down because it allows the muscle to be ready to receive the next signal. Therefore in the first stages of exercise because there are increased amounts of signals to produce rapid muscle contractions there is increased amounts of Acetylcholine production therefore the enzyme Cholinesterase has to be increased in order to break down the Acetylcholine quick enough to be ready to produce the next muscle signal.

9. USING GRAPHS, TABLES AND PRACTICAL EXPERIENCES TO SUPPORT YOUR ANSWER, ANALYSE THE NEUROMUSCULAR RESPONSES TO EXERCISE


From reviewing these diagrams, like most parts of our parts, neurones contain cells and these cells have different parts to them. The nucleus part of the neurone takes on any genetic information to signal how the cell should function, so if an athlete was about to carry out a bicep curl the brain would send signals of a muscle contract, the nucleus would then digest this information and inform the rest of the cell how to react to carry out the contraction. The mitochondria part of the cell allows the transformation of oxygen, glucose or sugars into energy, which is especially important when carrying out exercise because initially when you begin exercise all muscle contractions are increased exceptionally, therefore the neurones have to have the energy to produce the demand of contractions. The nucleus is also surrounded by an outer membrane this membrane acts as a filter to allow substances to flow either in and out of the neurone this allows the neurone to communicate with surrounding neurones, so during a contraction as enzymes are released to assist in contraction this substances may enter each individuals neurone nucleus therefore alerting it to contract quicker.

        The axon part of the neurone extend from the cell body, they allow information to be carried away from the cell body towards other neurones, so during a muscle contraction the muscle maybe receiving the message from a neurone several feet away, this is why they can vary greatly within size. Axons have a myelin sheath; this myelin is a fatty substance which insulates the axon which speeds the process of communication much quicker because the electrical signal can be carried quicker. This is why athletes must never completely get rid of any fat consumption because they require the fatty substances to increase the rate of communication between their axons.

        Towards the end of Axon’s are synaptic end bulbs these consist of vesicles which store neurotransmitters, special chemicals that are released during communication between neurones, so during a muscle contraction Synaptic end bulb would release the Acetylcholine which assists within the transmitting of the signal, and the Bulb would also produce the enzyme Cholinesterase which breaks down the Acetylcholine, so during contraction the Synaptic end Bulbs release of chemicals would be on an increase due to the demand of chemicals required during a muscle contraction.

        The Dendrites part of the neurone bring messages from other neurones into the cell body by releasing chemicals known as neurotransmitters from the Synaptic end bulb, special receptors are located on the end of the Dendrites and are designed to receive certain neurotransmitters, and if enough of these are received the message is cent to the cell body of the neurone. Due to this process much smaller contractions which require high amounts of skill are much harder to master this is because they require little messages sent rather than say if you wanted to contract the quadriceps there are many more dendrites which can locate large amounts of neurotransmitters.

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        The way neurones communicate, for an example say an athlete was trying to lift a weight to carry out a bicep curl, a sensory receptor would detect the force being applied along with the signal from the brain to signal that a force is being applied and it needs to be lifted, this is why the mechanical force of the athlete trying to lift the weight needs to be converted into an electrical force which the neurones can translate, this Action Potential is carried along the axon of the sensory receptor neurone towards a neuron within your spinal chord. The ...

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