State the glands labelled X and Y in the diagram.

Describe the function of adrenaline during exercise.

Describe how hormone levels are regulated.

Discuss the factors which may cause peripheral fatigue in a sprinter.

Explain what happens as an athlete breathes heavily after a 200 m sprint.

X = pancreas;

Y = adrenal gland(s);

stimulate glycogenolysis <in the liver and active muscles>;

stimulate lipolysis <in adipose tissue and active muscles>;

block glucose storage by the muscles;

facilitate sympathetic nervous activity within the body;

increase heart rate/cardiac output/contractility of the heart;

increase vasodilation of blood vessels within the muscles;

primarily controlled by negative feedback
OR
a stimulus elicits the release of a substance;

once the substance reaches a certain level, it sends a signal that stops further release of the substance;

chemical control of hormone release in response to changes in extracellular fluids eg a rise in blood glucose levels triggers the pancreatic release of insulin;

endocrine glands release hormones when stimulated by hormones released by other endocrine glands eg the hypothalamus produces hormones that stimulate the anterior portion of the pituitary gland;

the nervous system directly stimulates endocrine glands to release hormones, eg adrenaline stress response;

Award [1] max for a list with relevant examples.

fatigue is perceived differently by individual athletes and may depend on multiple factors, such as age;

prior training / level of fitness <will determine phosphate levels>;

in high intensity activities such as a sprint:

duration of the sprint will determine the rate of peripheral fatigue;

depletion of ATP stores
OR
depletion of creatine phosphate;

increase in levels of the products of exercise such as lactate and hydrogen ions
OR
lactate tolerance / body’s ability to buffer lactate;

diet / hydration status;

the greater the intensity of the exercise, the greater the EPOC;

initial stages of exercise, oxygen demand cannot be met by the aerobic system <oxygen deficit>
OR
initial stages are met by anaerobic processes;

oxygen deficit is paid back after exercise/oxygen debt;

alactacid/fast component is replenished with the first few minutes
OR
alactacid/fast component requires relatively less oxygen compared to the lactacid/slow component;

ATP and CP/PC stores are replenished;

myoglobin oxygen levels are replenished;

aerobically metabolize lactic acid;

resynthesize lactate to glycogen;

replacement of muscle / liver glycogen stores;

Generally answered well, although some candidates confused adrenal glands with kidneys.

Many candidates were able to identify the effect on heart rate. However, few were able to explain the wider effect e.g. glycogenolysis.

Many candidates struggled with this question. The most frequent response referred to a negative feedback loop. However, outlining the main three methods rarely had appropriate description and examples.

Candidates answered this reasonably well. Mainly responses focused ATP/PC depletion, dehydration and lactate tolerance.

Many candidates struggled with this question. Candidates were able to identify that oxygen debt was being paid back, but only a few candidates were able to describe the reasons for oxygen deficit. Few outlined the actions taking place during recovery.