Presentation is loading. Please wait.

Presentation is loading. Please wait.

Blood Vessels & Circulation

Similar presentations

Presentation on theme: "Blood Vessels & Circulation"— Presentation transcript:

1 Blood Vessels & Circulation
Chapter 13

2 Types of Blood Vessels Arteries Capillaries Veins
Blood vessels that carry blood away from the heart Capillaries microscopic blood vessels that allow exchanges between blood and tissue Veins Blood vessels that carry blood to the heart


4 General Features of Blood Vessels
Veins and arteries consist of three layers Tunica intima: innermost layer Tunica media: middle layer Tunica adventia: outermost layer

5 Arteries THREE TYPES OF ARTERIES Elastic arteries Largest in diameter
Thickest walls Mostly elastic tissue Stretch when ventricles pump into them Prevents blood pressure from falling rapidly Maintains blood flow when ventricles are relaxed

6 Arteries Muscular arteries Medium and smaller diameter
Made up of a lot of smooth muscle Control blood flow to different regions of body Vasoconstriction: Caused by contraction of smooth muscle in blood vessels Decreases blood vessel diameter and blood flow Vasodilation: Relaxation of smooth muscle in blood vessels Increases blood vessel diameter and blood flow


8 Arteries Small arteries Arterioles Smaller diameter Smaller walls
Smallest arteries Transport blood from small arteries to capillaries

9 Capillaries Structure Function
Single layer of simple squamous epithelium Diameter approximately the same as that of a red blood cell (7.5 micrometers) Function Receive blood from arterioles Branches out to form networks Regulated by precapillary sphincters Give up oxygen and nutrients to body tissues Take up carbon dioxide and other waste products from body tissues.

10 Single Erythrocyte squeezing through capillary

11 Capillaries Video Clip

12 Capillaries

13 Veins Venules Small Veins Medium Sized Veins
Receive deoxygenated blood from capillaries Diameter a little larger than capillaries Small Veins Receive blood from venules Medium Sized Veins Collect blood from small veins and deliver it to large veins


15 Veins Valves Found in veins that are larger than 2 millimeters in diameter. Allow blood to flow to the heart, but not backward Composed of two cusps, or flaps Similar in function to the semi-lunar valves Valve animation



18 Types of Blood Vessels Video Clip

19 Blood Pressure Blood Pressure= measure of force blood exerts against the blood vessel walls. Systolic: Top number. Pressure in the arteries when the ventricles contract. Diastolic: Bottom number. Pressure in the arteries between beats when ventricles are resting.

20 Blood Pressure

21 Blood Pressure Blood pressure values
Normal adult value is about 120 Hg systolic and 80 Hg diastolic or 120/80.

Download ppt "Blood Vessels & Circulation"

Similar presentations

Ads by Google