Principles of Anatomy and Physiology
Principles of Anatomy and Physiology
15th Edition
ISBN: 9781119329398
Author: Gerard J Tortora, Bryan Derrickson
Publisher: John Wiley & Sons Inc
bartleby

Concept explainers

Question
Book Icon
Chapter 21, Problem 1CP
Summary Introduction

To review:

The function of smooth muscles and elastic fibers in the arteries of tunica media.

Introduction:

The blood vessels, which transports the oxygenated blood from the heart to different body parts are known as arteries. In general, the wall of the blood vessels is composed of three distinct layers. The innermost layer is the tunica interna or intima, while tunica externa or adventitia is the outermost layer. Between these two layers is the tunica media.

Expert Solution & Answer
Check Mark

Explanation of Solution

The tunica media consists of the smooth muscle cells as well as the elastic fibers. The primary function of the cells of the smooth muscle that sheath the lumen of the vessel is to regulate its diameter in response to external stimuli. An increased sympathetic stimulus causes the smooth muscle cells to contract, which in turn narrows down the lumen.

This reduction in the blood vessel's lumen diameter is termed as vasoconstriction. On the contrary, a decreased sympathetic stimulus causes the cells of smooth muscle to relax leading to an increased lumen diameter. This process is called vasodilation. The cells of the smooth muscle also help in the production of the elastic fibers in the arteria's tunica media. These elastic fibers help increase the stretch or recoil the blood vessel depending on the pressure applied.

Conclusion

Thus, cells of the smooth muscle in tunica media respond to the external stimuli and cause the blood vessels to contract or dilate. The elastic fibers help the blood vessels to stretch or recoil under pressure and prevents their tearing when the pressure increases.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
1. In vivo testing provides valuable insight into a drug’s kinetics. Assessing drug kinetics following multiple different routes of administration provides greater insight than just a single route of administration alone. The following data was collected in 250 g rats following bolus iv, oral (po), and intraperitoneal (ip) administration.Using this data and set of graphs, determine: (a) k, C0, V, and AUC* for the bolus iv data  (b) k, ka, B1, and AUC* for the po data  (c) k, ka, B1, and AUC* for the ip data  (d) relative bioavailability for po vs ip, Fpo/Fip  (e) absolute po bioavailability, (f)Fpo absolute ip bioavailability, Fip    MAKE SURE ANSWERS HAVE UNITS if appropriate. SHOW ALL WORK, including equation used, variables used and each step to your solution.
2. Drug quantification from plasma is commonly performed by using techniques such as HPLC or LC/MS. However, these methods do have limitations, and investigators may choose to use a radiolabeled analog of a drug instead. Radioligands are molecules that contain radioactive isotopes, commonly 3H or 14C. This technique allows investigators to quantify drug concentration from radiation measurements. The following measurements were made in 250 g rats following oral administration of 18.2 µCi of a 14C-labeled drug of interest: Time (min) Plasma Radiation Levels (µCi/L) 0 0.0 2 9.7 4 19.2 7 25.3 9 37.8 12 39.6 14 45.8 17 48.8 20 52.0 25 56.4 30 59.2 35 60.1 40 61.1 45 62.1 50 62.8 60 63.1 70 62.1 80 60.1 90 57.3 100 55.5 110 53.7 120 52.2 150 48.0 180 45.0 240 39.0  Note that a µCi is a measure of the amount of radioactivity and hence is a measure of the amount of drug present.  Given that the oral bioavailability of this drug is known to be essentially 100%, estimate the following from this…
The current nutrition labelling regulation in Hong Kong requires food manufacturer to list E+7 information on the package of pre-packaged food products. Do you think that more nutrients, such as calcium and cholesterol, shall be included?
Knowledge Booster
Background pattern image
Biology
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Human Physiology: From Cells to Systems (MindTap ...
Biology
ISBN:9781285866932
Author:Lauralee Sherwood
Publisher:Cengage Learning
Text book image
Anatomy & Physiology
Biology
ISBN:9781938168130
Author:Kelly A. Young, James A. Wise, Peter DeSaix, Dean H. Kruse, Brandon Poe, Eddie Johnson, Jody E. Johnson, Oksana Korol, J. Gordon Betts, Mark Womble
Publisher:OpenStax College
Text book image
Curren'S Math For Meds: Dosages & Sol
Nursing
ISBN:9781305143531
Author:CURREN
Publisher:Cengage
Text book image
Basic Clinical Laboratory Techniques 6E
Biology
ISBN:9781133893943
Author:ESTRIDGE
Publisher:Cengage
Text book image
Biomedical Instrumentation Systems
Chemistry
ISBN:9781133478294
Author:Chatterjee
Publisher:Cengage
Text book image
Principles Of Radiographic Imaging: An Art And A ...
Health & Nutrition
ISBN:9781337711067
Author:Richard R. Carlton, Arlene M. Adler, Vesna Balac
Publisher:Cengage Learning