11.3 blood vessels
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11.3 Blood Vessels. Pages 487-494. Blood Vessels. 19 000 km . Arteries. Carry blood away from the heart 3-layers: Outer connective tissue (elastic) Middle muscle layer Inner epithelial layer (endothelium). Arterioles. Arteries branch into arterioles. Controlling blood flow. - PowerPoint PPT PresentationTRANSCRIPT
11.3 Blood Vessels
Pages 487-494
Blood Vessels
• 19 000 km
Arteries
• Carry blood away from the heart3-layers:Outer connective tissue (elastic)Middle muscle layerInner epithelial layer (endothelium)
Arterioles
• Arteries branch into arterioles
Controlling blood flow
Vasodilation: Increases diameter of blood vesselIncreased blood flow to the skinCooling strategy
Controlling Blood Flow
Vasoconstriction• Nerves cause smooth muscle to contract• Narrowing of blood vessel diameter• Restricts blood flow• Response to cold
Capillaries
• No cell is farther than two cells away from a capillary.
• Blood cells move through them in single file.
Pre-capillary sphincters
• Relax and increase blood flow during exercise
Venules and veins
• Return blood to the heart• Less elasticity in the walls• Less smooth muscles in the walls• Valves keep blood flowing in the right
direction
Varicose veins
• Damaged valves in legs
Blood pressure
• Sphygmomanometer• Blood pressure cuff• Inflated until blood flow ceases then released• Systolic pressure…heart contracts 120 mmHg• Diastolic pressure…heart relaxed
80 mm Hg
Hypertension
• High blood pressureDiet, age, weight, activity level, medication are contributors to high blood pressure
Lymphatic System
• Circulatory system and immune system• Maintains blood volume• Destroys foreign invaders
Lymph
• Proteins from blood tissue fluidlymph vessels veins
Contains fluid, germs, dead or damaged cells, fat from lacteals of villi
Lymph nodes filter out germs
Spleen and tonsils
• Spleen filters lymphatic system, reservoir for RBC’s and WBC’s
• Tonsils filter germs/enlarge
thymus
• Secretes hormones that help lymphocytes, a type of leuknocyte, develop their ability to recognize and attack foreign invaders