プリンキピア

第40章循環器系

Section Summaryこの節のまとめ

In most animals, the circulatory system is used to transport blood through the body. Some primitive animals use diffusion for the exchange of water, nutrients, and gases. However, complex organisms use the circulatory system to carry gases, nutrients, and waste through the body. Circulatory systems may be open (mixed with the interstitial fluid) or closed (separated from the interstitial fluid). Closed circulatory systems are a characteristic of vertebrates; however, there are significant differences in the structure of the heart and the circulation of blood between the different vertebrate groups due to adaptations during evolution and associated differences in anatomy. Fish have a two-chambered heart with unidirectional circulation. Amphibians have a three-chambered heart, which has some mixing of the blood, and they have double circulation. Most non-avian reptiles have a three-chambered heart, but have little mixing of the blood; they have double circulation. Mammals and birds have a four-chambered heart with no mixing of the blood and double circulation.
大半の動物では、循環器系が体内で血液を運ぶ。一部の原始的な動物は、水、栄養素、気体の交換に拡散を利用するが、複雑な生物は循環器系によって気体、栄養素、老廃物を体内で運ぶ。循環器系には、間質液と混ざる開放血管系と、間質液から分けられた閉鎖血管系がある。閉鎖血管系は脊椎動物の特徴である。しかし、進化中の適応と、それに伴う解剖学的な違いにより、心臓の構造や血液循環は脊椎動物の群ごとに大きく異なる。魚類は2室の心臓と一方向の循環をもつ。両生類は3室の心臓と二重循環をもち、血液が一部混ざる。鳥類以外の爬虫類の大半は3室の心臓をもつが、血液の混合は少なく、二重循環を行う。哺乳類と鳥類は4室の心臓をもち、血液が混ざらない二重循環を行う。

Review Questions確認問題

Exercises 1–3練習問題 1–3
Exercise 1問題 1
Why are open circulatory systems advantageous to some animals?
開放血管系が一部の動物にとって有利なのはなぜか。
  1. They use less metabolic energy.
    代謝に使うエネルギーが少ない。
  2. They help the animal move faster.
    より速く動けるようにする。
  3. They do not need a heart.
    心臓を必要としない。
  4. They help large insects develop.
    大型の昆虫の発達を助ける。
Solution解き方
A
A
Exercise 2問題 2
Some animals use diffusion instead of a circulatory system. Examples include:
循環器系の代わりに拡散を利用する動物の例はどれか。
  1. birds and jellyfish
    鳥類とクラゲ
  2. flatworms and arthropods
    扁形動物と節足動物
  3. mollusks and jellyfish
    軟体動物とクラゲ
  4. none of the above
    上のいずれでもない
Solution解き方
D
D
Exercise 3問題 3
Blood flow that is directed through the lungs and back to the heart is called ________.
肺を通って心臓へ戻る血液の流れを、＿＿＿＿という。
  1. unidirectional circulation
    一方向の循環
  2. gill circulation
    えら循環
  3. pulmonary circulation
    肺循環
  4. pulmocutaneous circulation
    肺皮循環
Solution解き方
C
C

Critical Thinking Questions考察問題

Exercises 4–5練習問題 4–5
Exercise 4問題 4
Describe a closed circulatory system.
閉鎖血管系を説明しなさい。
Solution解き方
A closed circulatory system is a closed-loop system, in which blood is not free in a cavity. Blood is separate from the bodily interstitial fluid and contained within blood vessels. In this type of system, blood circulates unidirectionally from the heart around the systemic circulatory route, and then returns to the heart.
閉鎖血管系は、血液が体の空洞へ自由に流れ出さない、閉じた回路である。血液は体の間質液と分けられ、血管内に収められている。血液は心臓から体循環の経路を一方向に流れ、その後心臓へ戻る。
Exercise 5問題 5
Describe systemic circulation.
体循環を説明しなさい。
Solution解き方
Systemic circulation flows through the systems of the body. The blood flows away from the heart to the brain, liver, kidneys, stomach, and other organs, the limbs, and the muscles of the body; it then returns to the heart.
体循環は、体の各器官系をめぐる。血液は心臓から、脳、肝臓、腎臓、胃などの器官、四肢、筋へ流れ、その後心臓へ戻る。
atrium
心房
(plural: atria) chamber of the heart that receives blood from the veins and sends blood to the ventricles
英語の複数形はatria。静脈から血液を受け取り、心室へ送る心臓の部屋。
closed circulatory system
閉鎖血管系
system in which the blood is separated from the bodily interstitial fluid and contained in blood vessels
血液が体の間質液から分けられ、血管内に収められている系。
double circulation
二重循環
flow of blood in two circuits: the pulmonary circuit through the lungs and the systemic circuit through the organs and body
肺を通る肺循環と、体や器官をめぐる体循環という、2つの回路で血液が流れること。
gill circulation
えら循環
circulatory system that is specific to animals with gills for gas exchange; the blood flows through the gills for oxygenation
ガス交換のためのえらをもつ動物に特有の循環。血液はえらを通り、酸素を取り込む。
hemocoel
血体腔
cavity into which blood is pumped in an open circulatory system
開放血管系で血液が送り込まれる体の空間。
hemolymph
血リンパ
mixture of blood and interstitial fluid that is found in insects and other arthropods as well as most mollusks
昆虫などの節足動物や、大半の軟体動物に見られる、血液と間質液の混合物。
interstitial fluid
間質液
fluid between cells
細胞の間にある液体。
open circulatory system
開放血管系
system in which the blood is mixed with interstitial fluid and directly covers the organs
血液が間質液と混ざり、器官を直接取り囲む系。
ostium
心門
(plural: ostia) holes between blood vessels that allow the movement of hemolymph through the body of insects, arthropods, and mollusks with open circulatory systems
英語の複数形はostia。開放血管系をもつ昆虫、節足動物、軟体動物で、血リンパを体内で移動させる、血管間の開口部。
pulmocutaneous circulation
肺皮循環
circulatory system in amphibians; the flow of blood to the lungs and the moist skin for gas exchange
両生類の循環系。ガス交換のため、肺と湿った皮膚へ血液が流れる。
pulmonary circulation
肺循環
flow of blood away from the heart through the lungs where oxygenation occurs and then returns to the heart again
心臓を出た血液が肺で酸素を取り込み、再び心臓へ戻る流れ。
systemic circulation
体循環
flow of blood away from the heart to the brain, liver, kidneys, stomach, and other organs, the limbs, and the muscles of the body, and then the return of this blood to the heart
心臓から、脳、肝臓、腎臓、胃などの器官、四肢、筋へ血液が流れ、その後心臓へ戻ること。
unidirectional circulation
一方向の循環
flow of blood in a single circuit; occurs in fish where the blood flows through the gills, then past the organs and the rest of the body, before returning to the heart
単一の回路を通る血流。魚類では、血液がえらを通り、次いで器官や体の残りの部分を通過して、心臓へ戻る。
ventricle
心室
(heart) large inferior chamber of the heart that pumps blood into arteries
心臓の下側にある大きな部屋で、動脈へ血液を送り出す。