Heart and Circulation — Part 2: Blood vessels, pulse and blood pressure: visual lesson, ICSE Class 10 Biology (Science Paper 3)

Lesson

Blood Vessels, Pulse and Blood Pressure

Part 2 — the pipes of the circulatory system and what they tell a doctor.

In this lesson you will

Compare arteries, veins and capillaries in wall, lumen, valves and direction of flow
Explain what the pulse is and interpret a blood pressure reading such as 120/80 mm Hg
Name the main vessels of the liver and kidney and explain the hepatic portal system

Diagram

Arteries: thick, elastic walls. Veins: thin walls, valves. Capillaries: wall one cell thick.

Concept

Table comparing arteries, veins and capillaries
Feature	Artery	Vein	Capillary
Direction	Away from heart	Towards heart	Between artery and vein
Wall	Thick, muscular, elastic	Thin, less muscle	One cell thick
Lumen	Narrow	Wide	Very narrow
Valves	None (except at the base)	Present	None
Pressure	High, in surges	Low, steady	Falling
Blood	Oxygenated (except pulmonary artery)	Deoxygenated (except pulmonary veins)	Mixed