Photo AI
The temperature of Rebecca’s brain and of one of her fingers was recorded at six different external temperatures - Edexcel - GCSE Biology - Question 5 - 2013 - Paper 1
Question 5
The temperature of Rebecca’s brain and of one of her fingers was recorded at six different external temperatures. | external | brain | finger | |----------|-------|... show full transcript
Worked Solution & Example Answer:The temperature of Rebecca’s brain and of one of her fingers was recorded at six different external temperatures - Edexcel - GCSE Biology - Question 5 - 2013 - Paper 1
Step 1
Calculate the maximum temperature range for Rebecca’s finger.
Answer
To calculate the maximum temperature range for Rebecca's finger, we need to find the difference between the highest and lowest finger temperatures recorded. The highest temperature is 37.0 °C at an external temperature of 20 °C and the lowest is 34.3 °C at an external temperature of -5 °C. The maximum temperature range can be calculated as follows:
Thus, the maximum temperature range for Rebecca’s finger is 2.7 °C.
Step 2
Compare the temperature of Rebecca’s brain and her finger as the external temperature decreased.
Answer
As the external temperature decreased, Rebecca's brain temperature mostly fluctuated and did not change significantly, remaining relatively stable. In contrast, the temperature of her finger decreased more noticeably, indicating that there was a greater loss of warmth from the finger than from the brain. This suggests that the brain temperature is better regulated compared to the finger, which is more exposed to the external conditions.
Step 3
Explain why the temperature of Rebecca’s finger showed this response to the decrease in the external temperature.
Answer
The temperature of Rebecca’s finger showed this response due to several physiological factors:
-
Heat Loss to the Environment: The fingers are more exposed to the external environment, leading to greater heat loss.
-
Less Blood Delivered to the Skin's Surface: As external temperatures drop, the body prioritizes blood flow to vital organs, reducing blood flow to the skin and extremities such as the fingers.
-
Narrowing of the Arteries: The body responds to cold by constricting the blood vessels supplying the skin surface, which minimizes heat dissipation.
-
Vasoconstriction: This physiological response decreases blood flow to the fingers, further contributing to cooling as less warm blood is delivered there.
-
Heat Loss by Radiation: With reduced blood flow and exposure to cold, the fingers lose heat more rapidly through radiation.
These combined factors account for the decrease in the temperature of Rebecca’s finger in response to the falling external temperature.