Question

Give reasons for the following.
(i) Blood flowing away from the stomach and intestines is put into circulation via the liver and not directly.
(ii) The arteries are deep-seated in the body.

Answer 1

(i) Introduction:-

1. Veins are blood vessels that deliver blood to the heart in humans and most other animals.
2. They carry deoxygenated blood from the tissues to the heart.

Veins from stomach and intestine:

1. The veins leading from the stomach and intestines do not carry blood straight to the posterior vena cava.
2. They enter the liver as a combined hepatic portal vein first.
3. In contrast to the basic features of a vein, this vein breaks up into capillaries, and their reunion forms a new vein that enters the posterior vena cava.
4. As a result, surplus nutrients in the blood are absorbed and stored in the liver, while just the necessary quantity is transported to other regions of the body.

(ii) Introduction

1. Blood vessels that carry oxygen-rich blood from the heart to the body's tissues are known as arteries.
2. Each artery is a three-layered muscular tube bordered by smooth tissue.
3. The intima is the inner layer, which is bordered by a smooth tissue known as the endothelium.

Arteries:

1. The arteries have thick, muscular, elastic walls.
2. They lack valves in their inner linings.
3. The blood runs through them with jerks and at high pressure.
4. As a result, they are deeply ingrained in the body.

Final answer:

(i) The blood from the stomach and intestine is put into the circulation via the liver through the hepatic portal vein.
(ii) The arteries are deep-seated to transport the blood at a higher pressure to all the organs and to prevent damage.