Question

Найдите на влажном препарате сердце. Установите его место расположения в полости тела. Какие органы относятся к кровеносной системе? Почему такая кровеносная система называется замкнутой? Про рыб.

Answer 1

У рыб один круг кровообращения и двухкамерное сердце. Кровеносная система замкнутая, транспортирует кровь от сердца через жабры и ткани тела. В отличие от сердца других позвоночных, сердце рыб не приспособлено для разделения (даже частичного) обогащенной кислородом крови (артериальной) от не обогащенной (венозной) . Структурно сердце рыб представляет собой последовательную серию из камер, заполненных венозной кровью: венозный синус, предсердие, желудочек и артериальный конус. Камеры сердца разделены клапанами, которые позволяют крови при сокращении сердца двигаться только в одном направлении (от венозного синуса к артериальному конусу) , но не наоборот.
Основным органом газообмена рыб являются жабры, которые расположены по сторонам ротовой полости.

Answer 2

Location of the Heart in the Body

The heart is located in the chest cavity, specifically in the thoracic cavity, between the lungs. It is positioned slightly to the left of the midline of the body. The heart is protected by the rib cage and rests on the diaphragm, which is a muscle that separates the chest cavity from the abdominal cavity.

Organs of the Circulatory System

The circulatory system, also known as the cardiovascular system, is responsible for the transportation of blood, nutrients, oxygen, and waste products throughout the body. The main organs and structures that make up the circulatory system include:

1. Heart: The heart is a muscular organ that pumps blood throughout the body. It consists of four chambers: two atria and two ventricles. The atria receive blood, while the ventricles pump blood out of the heart.

2. Blood Vessels: Blood vessels are the network of tubes that carry blood to and from the heart. There are three types of blood vessels: arteries, veins, and capillaries. Arteries carry oxygenated blood away from the heart, veins carry deoxygenated blood back to the heart, and capillaries are tiny blood vessels that allow for the exchange of nutrients and waste products between the blood and body tissues.

3. Arteries: Arteries are blood vessels that carry oxygenated blood away from the heart to various parts of the body. They have thick, elastic walls that help maintain blood pressure.

4. Veins: Veins are blood vessels that carry deoxygenated blood back to the heart from the body tissues. They have thinner walls compared to arteries and contain valves that prevent the backflow of blood.

5. Capillaries: Capillaries are the smallest blood vessels in the body. They connect arteries and veins and allow for the exchange of oxygen, nutrients, and waste products between the blood and body tissues.

Closed Circulatory System

The circulatory system is referred to as a closed circulatory system because the blood is contained within a network of blood vessels and does not directly come into contact with the body tissues. In a closed circulatory system, blood is continuously circulated throughout the body in a closed loop. This system allows for efficient transport of substances and helps maintain blood pressure and flow.

In contrast, an open circulatory system, found in some invertebrates, does not have a network of blood vessels. Instead, the blood directly bathes the body tissues.

The closed circulatory system in humans and other vertebrates provides several advantages, including more precise control of blood flow, the ability to regulate blood pressure, and the separation of oxygenated and deoxygenated blood.

Fish Circulatory System

Fish have a circulatory system that is similar to the closed circulatory system found in humans and other vertebrates. However, there are some differences in the structure and function of their circulatory system.

In fish, the heart is a two-chambered organ, consisting of one atrium and one ventricle. The blood is pumped from the heart to the gills, where it picks up oxygen and gets rid of carbon dioxide. From the gills, oxygenated blood is then distributed to the rest of the body through arteries. Deoxygenated blood returns to the heart through veins.

Fish also have a single circuit circulatory system, meaning that blood passes through the heart only once during each complete circuit of the body. This is in contrast to mammals, where blood passes through the heart twice during each complete circuit.

Overall, the circulatory system in fish serves the same purpose as in humans and other vertebrates, which is to transport oxygen, nutrients, and waste products throughout the body.

I hope this information is helpful! Let me know if you have any more questions.