Lesson 1 Flashcards
- Describe the three layers of tissue that form an artery.
Arteries have three layers of tissues. The inside layer is formed of epithelial tissue, the middle layer is a thick layer of smooth muscle and elastic tissue and the outer layer is composed of connective tissue
- What is an arteriole and explain how the diameter of an arteriole can affect blood pressure?
An arteriole is a small artery. The wall of these smaller vessels is formed primarily of smooth muscle. When the smooth muscle is contracted, the vessel’s diameter decreases and this is referred to as constriction of the vessel. When the smooth muscle is relaxed, the diameter increases and this is referred to as the dilation of the vessel. The larger the diameter of the vessel, the lower the pressure will be, that is exerted by the blood against the walls of the vessel. As well, the more arterioles that are dilated the lower will be the blood pressure.
- Describe the size, surface area and function of a capillary.
Capillaries are extremely narrow tubes with one-cell thick walls composed of epithelial tissue only. In spite of their size, they have a large total surface area. The function of capillaries is to allow for the exchange of substances between themselves and body cells as material diffuses across their thin walls. Capillaries join arteries with veins to form a closed circuit for the flow of blood throughout the body
- Why are capillaries such an important part of the human cardiovascular system?
Capillaries are an important part of the human cardiovascular system because they surround every cell of the body allowing oxygen and nutrients to diffuse into the cell, carbon dioxide and wastes to diffuse out of the cells. At any given time only certain capillaries are open and others are closed, depending on the needs of the body.
- What is the function of venules and veins?
The function of venules and veins is to receive blood from capillaries and carry the blood back towards the heart. These vessels can also act as blood reservoirs.
- Compare the anatomy of veins and arteries.
Veins have thinner walls than arteries. They have the same three layers as arteries, but the middle layer of smooth muscle is much less
- What purpose do valves serve?
Veins involved in the flow of blood against gravity contain valves. When open, valves allow for one-way flow of blood back to the heart, and when closed, prevent the back flow of blood.
- Name the three types of blood vessels and what each does in terms of the direction it is carrying blood.
The cardiovascular system has three types of blood vessels: arteries (and arterioles) carry blood away from the heart to the capillaries; capillaries allow for the exchange of material with the tissues (cells); veins (and venules) return blood from the capillaries to the heart.
