Describe nervous control of ventilation during exercise.

Using examples, outline why identical twins share some human characteristics whereas others are very different.

Using the characteristics of the three phases of learning, describe the skill development of a child learning to walk.

Explain the relationship between the hypothalamus and the pituitary gland, with specific reference to effective bodily functions.

Discuss the structure and function of the leg muscle fibres of an elite long jumper and a marathon runner.

nervous system:

breathing is manipulated by the autonomic nervous system to increase rate <expiratory centre> & increase depth <inspiratory centre> of breathing in response to exercise;

respiratory centre is found in the brain stem/medulla oblongata & pons in the brain;

chemoreceptors relay information to the respiratory centre regarding lower pH or O₂ / higher CO₂ levels

OR

proprioceptors relay information to the respiratory centre regarding action of muscles / spindles / joint receptors;

<inspiratory> respiratory centre increases stimulation <via phrenic nerve and intercostal nerves> to the inspiratory muscles <external intercostals and diaphragm>;

during exercise inspiratory muscles are stimulated to contract more forcefully;

<inspiratory> respiratory centre stimulates additional accessory muscles <sternocleidomastoid, pectoralis minor, scalenes> to contract <to increase depth of breathing>;

during forceful ventilation nerve impulses from the inspiratory area activate the expiratory area;

stretch/mechano receptors in the lungs <and bronchioles> relay information to the respiratory centre to prevent over inflation of the lungs;

in response to stretch receptors, <expiratory> respiratory centre shortens the duration of inspiration / Hering-Bruer reflex;

<expiratory> respiratory centre stimulates expiratory muscles <internal intercostals / obliques / rectus abdominus> to contract;

expiration moves from passive to active control during exercise;

Max [2] if no reference to exercise.

some characteristics are expressed developmentally by genes

<these are determined at birth / genetic predisposition>;

e.g. eye colour;

other characteristics are expressed environmentally;

e.g. height influenced by nutrition;

Award [1] if only an example is given.

Cognitive (beginner)

learning through trial and error, child will continuously try to master the skill;

many large errors are made, basic mistakes of balance and coordination/lacks fluency;

Associative (practice stage)

number and size of errors reduce, child falls over less;

child begins to feel how walking / the skill should be executed, confidence develops however difficulty still with multi-tasking;

Autonomous (final stage)

motor programs are automatic;

this allows performer to concentrate on other stimuli;

changes can be made without external feedback;

skill is biomechanically efficient;

All three phases must be addressed for [4].

Max [2] per stage.

No marks for identification of phases alone.

hypothalamus receives information from elsewhere in the body;

the hypothalamus is the part of the brain that controls/sends messages to the pituitary gland;

creating feedback loop which helps to maintain homeostasis;

nerve impulses from the hypothalamus stimulate the pituitary gland;

GHRH/growth hormone releasing hormone is a neurohormone released from the hypothalamus which directly influences the pituitary gland to release GH/growth hormone to regulate growth;

somatostatin is a neurohormone released from the hypothalamus to inhibit the pituitary gland from releasing GH;

pituitary gland stimulates the release of antidiuretic hormone/ADH for water regulation;

Require an explanation for mark, candidates cannot just list structural and functional characteristics.

Max [4] for either athlete.

This was a poorly answered question. Many candidates completely misinterpreted the question and described the mechanics of breathing with no reference to exercise. Many of those who understood the requirements of the question focused on cardiovascular control rather than ventilatory control. Those who were able to access marks described the receptors involved but struggled to describe how this information was used to effect changes in breathing during exercise.

This question was raised within the G2 form. Candidates were not required to have detailed knowledge of twins, however the question required candidates to understand how genotypes are expressed. For example, developmentally or due to an environmental switch and provide examples of these phenotypes.

This question was also raised within the G2 forms. As the course is sport, exercise and health science, not all applied examples will relate directly to a competitive sport. Many candidates understood the concepts of cognitive, associative and autonomous and were able to correctly describe the stages of learning chronologically. However, many candidates struggled with applying their knowledge to describe how a learner changes from cognitive to autonomous. Candidates found describing the autonomous stage the easiest and found the associative stage the hardest.

Of the candidates who had selected question 9, few attempted this question. Most candidates who did respond to this question were able to identify that the hypothalamus controls the pituitary gland. Although many were able to explain the hormonal relationship between the two structures, few candidates referred to neural control or were able to apply the appropriate bodily function.

Of candidates who chose to answer question 9, many did not attempt this question. Candidates were required to discuss the structural and functional characteristics of the muscle fibres of two contrasting athletes. Most candidates were able to identify the correct dominant muscle fibre type for each sport. However, many struggled to identify the appropriate characteristics of these fibre types. For candidates who were able to accurately identify the appropriate characteristics they were often a list rather than a discussion. Candidates were required to apply their knowledge of the characteristic and provide more detail as to how this would enable the athlete to complete the relevant sport.