1. March 7, 2016
Journal: Paul gets into a car accident and loses a lot of blood. He needs to have a blood transfusion to replace the lost blood. If his blood type is AB-, what types of blood can be donated to him?

2. Blood Vessels

3. Pathway of Blood Leaving the Heart
Aorta
Arteries
Arterioles
Capillaries  oxygen and nutrients given to the cells of your body and exchanged for waste
Venules
Veins
Superior and Inferior Vena Cava

4. Walls of the Blood Vessels
Three Layers:
Tunica interna: inner layer
Made up of squamous epithelial cells over a thin layer of connective tissue that allows blood to easily pass through
Tunica media: middle layer
Made up of smooth muscle and elastic and collagen tissue that can expand and contract to control the diameter of the vessel
Tunica externa: outer layer
Made of fibrous tissue and provides support and protection for the blood vessel

5. Arteries vs. Veins Arteries = thicker walls Veins
Contain elastic laminae – extra layer of elastic tissue to help deal with increased pressure
Veins
Contain valves to prevent backflow that may be caused by the low pressure
Surrounded by skeletal muscle that can contract to push blood toward the heart

6. Capillaries
Only made up of tunica interna so the walls are only one cell thick
Allows for oxygen, nutrients, and wastes to easily pass through to the tissue cells
Come together to form a web of vessels called a capillary bed

7. Capillary Beds Made up of:
Vascular Shunt: main road connecting the arteriole to the venule
True Capillaries: vessels that make up the actual exchanges with the tissues
Precapillary Sphincters: smooth muscle that dictate if blood can flow through or not