Essentials of Anatomy and Physiology Fifth edition Seeley, Stephens and Tate Slide 2.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Chapter 13: Blood Vessels and Circulation

The Heart: Regulation of Heart Rate Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Increased heart rate  Sympathetic nervous system  Hormones  Epinephrine  Thyroxine  Exercise  Decreased blood volume

The Heart: Regulation of Heart Rate Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Decreased heart rate  Parasympathetic nervous system  Vagus X nerves  High blood pressure or blood volume  Decreased venous return

Blood Vessels: The Vascular System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Circulate blood throughout the body  Arteries  Arterioles  Capillaries  Venules  Veins

The Vascular System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.8b

Blood Vessels: Anatomy Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Three layers (tunics)  Tunic intima (interna)  Endothelium  Thinnest, slick  Tunic media  thickest  Smooth muscle

Tunics of Elastic and Muscular Arteries Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.8b

Blood Vessels: Anatomy Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Tunic externa  Mostly fibrous connective tissue  Provides support  Prevents over-expansion of vessels

The Vascular System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.8b

Differences Between Blood Vessel Types Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Walls of arteries are thickest  Especially tunica media  More smooth muscle  More elastic tissue  Lumens of veins are larger

The Anatomy of Veins Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.8b

Differences Between Blood Vessel Types Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Walls of veins are thin  May have valves  Usually in veins below heart  Prevent backflow  Valves assisted by skeletal muscle

Movement of Blood Through Vessels Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Arterial blood is pumped by the heart  Veins use the milking action of muscles to help move blood Figure 11.9

Vessels: Anatomy of a Capillary Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Capillaries  Form vast, complex networks  Walls one cell layer thick  Thin, leaky  Allow for exchange of materials

Capillary Beds Slide 11.28a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Capillary beds: networks  Vascular shunt: directly connects an arteriole to a venule Figure 11.10

Capillary Beds Slide 11.28b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Exchange vessels  Oxygen and nutrients exit blood  Carbon dioxide and waste products enter blood Figure 11.10

Blood Vessels: Did you know…. Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Humans have about 60,000 miles of vessels  Vessels reach every millimeter of tissue  We have at least two veins for every artery in our extremities  We have 200 miles of vessels in every pound of adipose tissue

Capillary Exchange Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Substances exchanged due to concentration gradients (diffusion!)  Oxygen and nutrients leave the blood, enter cells  Carbon dioxide and other wastes leave the cells, enter blood

Diffusion at Capillary Beds Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.20

Special Circuits: Cerebral Arterial Circle Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.13

Special Circuits: Hepatic Portal System Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.14

Special Circuits: Fetal Circulation Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.15

Pulse Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Pulse: pressure wave of blood  Caused by contraction of heart  Monitored at superficial “pressure points” Figure 11.16

Pulse Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Pulse – should match heart rate  Averages beats/minute Figure 11.16

Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Measurements are made on the pressure in large arteries  Commonly use brachial artery  Systolic – pressure at the peak of ventricular contraction  Diastolic – pressure when ventricles relax

Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Pressure in blood vessels  decreases with distance from the heart  Is lowest in venous system

Measuring Arterial Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.18

Factors Determining Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 11.19

Variations in Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Human normal range is variable  Normal  140–110 mm Hg systolic  80–75 mm Hg diastolic  120/80 is “ideal” B.P.

Variations in Blood Pressure Slide Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings  Hypotension  Low systolic (below 110 mm Hg)  May be associated with illness  Hypertension  High systolic (above 140 mm Hg)  High diastolic (above 90 mm Hg)  Can be dangerous:  stroke, heart attack, blindness