BPK 105 Study Guide - Final Guide: Elastic Fiber, Blood Vessel, Loose Connective Tissue

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Modules 7 & 8 - Review Questions - Part 6
11. Compare and contrast the structure and function of elastic arteries, muscular arteries
and capillaries. List the functions of the circulatory system that each type of vessel
contributes to. [5 marks]
The three main types of blood vessels are arteries, capillaries, and veins. Arteries carry blood away from
the heart; usually, the blood is oxygen-rich.
- Blood is pumped from the ventricles of the heart into large, elastic arteries, which branch
repeatedly to form progressively smaller arteries.
- As they become smaller, the artery walls undergo a gradual transition from having more elastic
tissue than smooth muscle to having more smooth muscle than elastic tissue (figure 13.1a–c
).
- The arteries are normally classified as elastic arteries, muscular arteries, or arterioles, although
they form a continuum from the largest to the smallest branches.
Blood flows from arterioles into capillaries, where exchange occurs between the blood and the tissue
fluid. Capillaries have thinner walls than do arteries (figure 13.1d
). Blood flows through them more
slowly, and there are far more of them than of any other blood vessel type.
From the capillaries, blood flows into veins. Veins carry blood toward the heart; usually, the blood is
oxygen-poor. Compared to arteries, the walls of veins are thinner and contain less elastic tissue and
fewer smooth muscle cells (figure 13.1e–g
). Starting at capillaries and proceeding toward the heart, small-
diameter veins come together to form larger-diameter veins, which are fewer in number. Veins increase in
diameter and decrease in number as they progress toward the heart, and their walls increase in
thickness. Veins may be classified as venules, small veins, medium- sized veins, or large veins.
The heart pumps blood through elastic arteries, muscular arteries, and arterioles to the capillaries.
Arteries
1. Large, elastic arteries have many elastic fibers but little smooth muscle in their walls. They carry blood from the
heart to smaller arteries with little decrease in pressure.
2. The walls of muscular arteries have much smooth muscle and some elastic fibers. They undergo vasodilation and
vasoconstriction to control blood flow to different regions of the body.
3. Arterioles, the smallest arteries, have smooth muscle cells and a few elastic fibers. They undergo vasodilation and
vasoconstriction to control blood flow to local areas.
Capillaries
1. Capillaries consist of only endothelium and are surrounded by a basement membrane and loose connective
tissue.
2. Nutrient and waste exchange is the principal function of capillaries.
3. Blood is supplied to capillaries by arterioles. Precapillary sphincters regulate blood flow through capillary
networks.
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Document Summary

Modules 7 & 8 - review questions - part 6: compare and contrast the structure and function of elastic arteries, muscular arteries and capillaries. List the functions of the circulatory system that each type of vessel contributes to. The three main types of blood vessels are arteries, capillaries, and veins. Arteries carry blood away from the heart; usually, the blood is oxygen-rich. Blood is pumped from the ventricles of the heart into large, elastic arteries, which branch repeatedly to form progressively smaller arteries. As they become smaller, the artery walls undergo a gradual transition from having more elastic tissue than smooth muscle to having more smooth muscle than elastic tissue (figure 13. 1 a c ). The arteries are normally classified as elastic arteries, muscular arteries, or arterioles, although they form a continuum from the largest to the smallest branches. Blood flows from arterioles into capillaries , where exchange occurs between the blood and the tissue fluid .

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