week 13

week 13 - Blood Vessels...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Blood Vessels Heart arteries—arterioles capillaries venules veins heart 1. Arteries and arterioles: carry blood away from the heart. Thick and muscular with elastic walls 2. Capillaries o A. Where the exchange of wastes, nutrients, gases and hormones between blood and body cell occurs o B. Thin tubes with walls only one cell thick so that dissolved material can diffuse in and out o C. so narrow that RBCs must pass through them in a single file o Where exchange takes place in your body o Have extremely thin walls and makes it easy for substances to move by diffusion makes easy to move from outside to inside Moves from high concentration to low concentration o So narrow that only one red blood cell can pass through at a time o 50,000 miles of capillaries in your body o Smallest vessel system in your body 3. Venules and veins o A. provide low pressure pathways for blood back to the heart o B. walls are much thinner o Controlling blood flow: One way valves in veins—prevent back flow of blood o Modify blood in veins to get back to the heart Drop in blood pressure: the nervous system stimulates contraction of smooth muscles in the vein walls decreasing their diameter (blood pressure rises) Artery that carries unoxinated blood AND Vein that carries oxinated blood o Go into your lungs and break down, in your lungs are beds of capillaries that are tiny balls. There CO2 moves out of blood stream and then out of your body Inhale and bring in oxygen and goes from the air spaces in lungs into the bloodstream and then back into your heart in pulmonary vein o Hormone is released into a bed of capillaries and then they get transported throughout your whole body What is a heart attack! ON FINAL ! Respiration:
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 4

week 13 - Blood Vessels...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online