Question

1) List two physiological ways in which camels respond to hot, arid conditions. Explain HOW and WHY these adaptations help camels survive hot, arid conditions.

2) Camels have a long loop of Henle and a well-developed medulla. What are the purposes of these anatomical features? How do they help camels survive the hot, arid climates? Link what you learned in the lecture videos with this article.

3) Describe one way that camels reduce their water use and how this contributes to their ability to survive hot, arid climates.

4) What would happen if an Angus steer (the steer is acclimated to living in Northern Colorado) was transported to and immediately dropped off in The Mojave Desert? Describe 3 physiological effects that would occur. What are the results of these effects?

Answer 1

Camels exhibit several morphological, anatomical, and physiological adaptations to survive in hot arid conditions.
Morphological and anatomical adaptations:
1. Large, flat feet
2. Thick fur at the top to provide shade and thin fur below to allow heat transfer
3. Large surface area to volume ratio

Physiological adaptations:
1. The ability to survive a long time without water. This is accomplished by loss of a very little amount of water through perspiration and urination
2. High-temperature tolerance mechanisms in the body
3. They can lose up to 30% of body weight due to dehydration
4. Cattle lose 20-40 L of water through feces daily. Camels lose only 1.3 L. Fluid is absorbed in the end part of the intestine to reduce water loss
5. The kidney contains a long loop of henley and a well-developed medulla (The ratio between medulla to the cortex is 4:1). The long loop of Henle allows for both concentrates the urine and reduces its flow. During dehydration, water loss is reduced by both decreasing the glomerular filtration rate and by increasing tubular reabsorption of water.
6. The dehydration does not affect the viscosity of the blood. The composition of blood and functioning of hemoglobin remains normal even during dehydration. RBC is oval in shape and very expansible upon rehydration. Their life-span can be extended to 150 days during dehydration.
7. They exhibit selective brain cooling