Problem 5 - Campbell Biology

Question

One feature that amphiblans and humans have in common is (A) the number of heart chambers. (B) a complete separation of circuits for circulation. (C) the number of circuits for circulation. (D) a low blood pressure in the systemic circuit.

Step-by-Step Solution

Answer

Both amphibians and humans have two circuits for circulation.

Step 1: Identify the trait in question

The exercise asks about a feature that amphibians and humans have in common. Carefully consider each option provided to see which characteristic applies to both species.

Step 2: Examine the number of heart chambers

Humans have four heart chambers: two atria and two ventricles. Amphibians, such as frogs, have three heart chambers: two atria and one ventricle. Therefore, there is no commonality in the number of heart chambers between amphibians and humans.

Step 3: Evaluate the separation of circulation circuits

Humans have a complete separation of systemic and pulmonary circuits in the heart. Amphibians do not: their single ventricle mixes oxygenated and deoxygenated blood to some extent. Thus, they do not share a complete separation of circuits for circulation.

Step 4: Assess the number of circuits for circulation

Both humans and amphibians have two circuits for circulation: pulmonary (lungs) and systemic (rest of the body). This is a common feature between the two species.

Step 5: Consider the systemic blood pressure

Humans typically have relatively high systemic blood pressure to efficiently deliver blood to various body parts. Amphibians have lower systemic blood pressure. Therefore, they do not share similar systemic blood pressures.

Step 6: Determine the correct answer

Based on the evaluation of the options, the trait that amphibians and humans share is the number of circuits for circulation. Both have two circuits.

Key Concepts

Amphibian Circulatory System

The amphibian circulatory system is a fascinating adaptation to a life both in water and on land. Amphibians, such as frogs, have a three-chambered heart consisting of two atria and one ventricle. This division allows for some separation of oxygenated and deoxygenated blood. However, because there is only one ventricle, the oxygenated and deoxygenated blood can still mix to some extent.

Amphibians rely on both their skin and lungs for respiration. This dual mode of breathing requires a circulatory system that can efficiently transport blood to both the lungs and the skin. Hence, the amphibian circulatory system consists of two circuits: the pulmonary circuit and the systemic circuit. The pulmonary circuit moves blood between the heart and the lungs, while the systemic circuit circulates blood throughout the rest of the body.

Although their circulatory system is less efficient than that of mammals, it is well-suited to the metabolic needs of amphibians, particularly given their often variable and lower levels of activity compared to mammals.

Human Circulatory System

The human circulatory system is highly efficient and consists of a four-chambered heart: two atria and two ventricles. This structure allows for a complete separation of oxygenated and deoxygenated blood, which is crucial for maintaining high levels of efficiency in oxygen and nutrient delivery to tissues.

The human heart's four chambers help segregate the pulmonary and systemic circuits entirely. Blood flows from the right atrium to the right ventricle, which then pumps it to the lungs via the pulmonary arteries. In the lungs, the blood becomes oxygenated and returns to the left atrium through the pulmonary veins. From there, it is sent to the left ventricle, which pumps it out to the rest of the body through the systemic circuit.

This complete separation of circuits ensures that the blood reaching the body's tissues is highly oxygenated, facilitating the high metabolic demands of human activities. Furthermore, the efficient circulation system supports high systemic blood pressure, enabling effective delivery of blood to all parts of the body, even against gravity.

Pulmonary and Systemic Circuits

Both amphibians and humans share a crucial feature: the presence of two primary circulatory circuits, the pulmonary and systemic circuits.

In the pulmonary circuit, blood is pumped from the heart to the lungs to pick up oxygen and release carbon dioxide. This oxygenated blood then returns to the heart. For humans, this is facilitated by the right side of the heart, specifically the right atrium and right ventricle. In amphibians, the process is similar, but owing to their three-chambered heart, some mixing of oxygenated and deoxygenated blood can occur.

The systemic circuit is responsible for delivering oxygen-rich blood to the rest of the body while returning deoxygenated blood back to the heart. In humans, this is driven by the left side of the heart, including the left atrium and left ventricle. For amphibians, despite having only one ventricle, the systemic circuit still functions to distribute blood throughout their bodies, albeit less efficiently.

Understanding these circuits is key to appreciating how both species manage oxygen delivery. For students studying comparative physiology, recognizing the similarities and differences in these systems can highlight how each species has adapted its circulatory system to meet its specific physiological demands.