The diagram represents skin.

Annotate structures A, B and C in the diagram.

Describe how skin allows for homeostasis.

Explain cardiovascular drift and the relevance of hydration during a 50 km walk.

contraction/dilation of blood vessels in the skin allow for regulation of body temperature;

contraction and relaxation of hair follicle <arrector pilli> muscles to allow regulation of body temperature;

subcutaneous layer provides insulation which can help maintain body temperature;

sweat glands allow perspiration / excretion / thermoregulation;

as a barrier/outermost organ of the body skin protects the body from thermal/UV/physical injury/foreign material;

sebaceous glands secrete sebum which helps to fight against bacteria on the skins surface;

as the skin contains many neurons it provides sensory information / for feedback systems;

exposure to sunlight skin synthesizes vitamin D to <support bone health/ control infections/reduce inflammation>;

Award [1 max] total for two or more functions with no description.

Award [3 max] for one the description of one function.

during prolonged exercise there is an increase in body temperature / blood flow is diverted to the skin;

cooling/sweating causes fluid loss/decreases in blood plasma;

this results in increased blood viscosity/decreased in stroke volume;

to maintain homeostasis/cardiac output (Q) there is a «gradual» increase in HR
OR
reduction in venous return/ stroke volume causes the heart rate to increase to maintain cardiac output;

during prolonged exercise an athlete can ingest drinks/stay hydrated to maintain blood volume/Q <to avoid/reduce cardiovascular drift>;

Award [3 max] for cardiovascular drift.

The assessment term for this question was annotate. This requires candidates to add brief notes to a diagram or graph. The format for candidate response may have led candidates to believe they needed to describe the function of the structure. Therefore examiners accepted either a note or a function. Most candidates were able to identify the sweat gland, but struggled with epidermis and dermis.

Responses were often focused around thermoregulation with many describing the role of sweat. Candidates had a general understanding of the role of skin plays but many candidates struggled to provide sufficient description to be credited marks.

Many candidates demonstrated a good understanding of this topic but several candidates did not answer this question. A number of candidates struggled to directly link the requirements for hydration.