Blood Vessels

• Blood vessels


  Form a closed vascular system that transports blood to the tissues and back to the heart
• Arteries and aterioles


  Vessels that carry blood away from the heart
• Capillary beds


  Vessels that play a role in exchanges between tissues and blood vessels
• Venues and veins


  Vessels that return blood toward the heart
• Tunica intima, tunica media, tunica externa


  What are the three layers of blood vessels (except capillaries)?
• Tunica intima


  - Forms a friction-reducing lining

  - Endothelium
• Tunica media


  - Smooth muscle and elastic tissue

  - Controlled by sympathetic nervous system
• Tunica externa


  - Forms protective outermost covering

  - Mostly fibrous connective tissue

  - Supports and protects the vessel
• Arteries


  What blood vessels have stronger, stretchier tunica media than veins to withstand changes in pressure?
• Veins


  What blood vessels have thinner tunica media than arteries and operate under low pressure?
• Valves


  Veins also have this structure to prevent backflow of blood
• Veins


  What type of blood vessel is lumen larger? Arteries or veins?
• True


  TRUE or FALSE. Skeletal muscle "milks" blood in veins toward the heart
• Operation of muscular pump

  - A vein receives blood from multiple branches and blood flows against gravity

  - When a vein gets squeezed by nearby skeletal muscle, the valve below the muscle contractions closes, while the valve above the muscle contraction opens, thereby allowing blood to flow upward.
• True


  TRUE or FALSE. Veins have multiple valves
• Valve below muscle contraction closes and valve above muscle contractions opens, making blood flow upward.


  What happens when a vein gets squeezed by nearby skeletal muscles?
• Capillaries

  - One cell layer thick (tunica intima)

  - Allow exchanges between blood and tissue

  - Form capillary beds
• Microcirculation


  What is the term for blood flow through a capillary bed
• Terminal arteriole -> exchange vessels of capillary bed -> postcapillary venule


  What is the blood flow in capillaries
• Precapillary sphincters and vascular shunt


  Special capillary beds have what?
• Precapillary sphincters


  Regulate blood flow in capillary beds
• Blood flows through the capillary beds and exchanges with cells occur


  What happens when precapillary sphincters are relaxed (open)?
• Blood flows through the vascular shunt and bypasses the cells in that region


  What happens when precapillary sphincters are contracted (closed)?
• Vascular shunt


  Directly connects the arteriole and venule at opposite ends of the capillary bed
• Aorta


  - Largest artery in the body

  - Leaves from the left ventricle of the heart

  - Regions of aorta: ascending aorta, aortic arch, thoracic aorta, abdominal aorta
• Left ventricle of heart


  Aorta leaves from what?
• Ascending aorta


  - Region of aorta

  - Leaves the left ventricle
• Aortic arch


  - Region of aorta

  - Arches to the left
• Thoracic aorta


  - Region of aorta

  - Travels downward through the thorax
• Abdominal aorta


  - Region of aorta

  - Passes through the diaphragm into the abdominopelvic cavity
• Coronary arteries


  Arterial branches of the ascending aorta

  - Right and left ___________ serve the heart
• Brachiocephalic trunk


  Arterial branches of aortic arch

  - ____________ splits into the: right common carotid artery & right subclavian artery
• Right common carotid artery and right subclavian artery


  - Arterial branches of the aortic arch

  - The brachiocephalic trunk splits into what two arteries?
• Left internal and external carotid arteries


  - Arterial branches of the aortic arch

  - What arteries does the left common carotid artery split into?
• - Vertebral artery

  - Axillary artery -> brachial artery -> radial and ulnar artery

  - Arterial branches of the aortic arch

  - What arteries does the left subclavian artery branch?
• Intercostal arteries


  What arteries supply the muscles of the thorax wall?
• Lungs (bronchial arteries), Esophagus (esophageal arteries), Diaphragm (phrenic arteries)


  What are the other arteries that the thoracic aorta supply?
• Bronchial arteries


  What arteries supply the lungs?
• Esophageal arteries


  What arteries supply the esophagus?
• Phrenic arteries


  What arteries supply the diaphragm?