Blood vessels & circulation Anatomy & Physiology

Circulation of Blood left side heart  aorta  branches of aorta (arteries)  arterioles  capillaries  venules  veins  vena cava  right side of heart  pulmonary circulation  left side of heart

Arteries any blood vessel carrying blood away from heart designed to withstand higher pressure than veins elastic: must swell to take up blood expelled by the heart swelling stretches elastic tissue & keeps the blood pressure fairly high between heart beats small arteries (arterioles)have muscles that control their diameters (precapillary sphincters): used to control blood flow thru an organ

cross-section of artery

Capillaries where materials delivered to/from cells  blood walls 1 squamous cell thick: so diffusion very fast not elastic

Types of Capillaries

Veins any blood vessel with blood flowing toward the heart low pressure vessels can expand to accommodate differing volumes of blood flow contain valves to stop backflow of blood

cross-section of vein with valve

Comparing Arteries & Veins

Blood Flow active organs like the liver, brain, kidneys have high blood flows @ rest Kidney: ~25% of cardiac output GI tract & liver: ~25% Muscle circulation @ rest: ~20% Brain: ~ 15%

Adaptions for Exercise during exercise: blood flow to active muscles greatly increases: up to 80% of cardiac output Blood flow to skin increases or decreases to regulate body temperature

Questions? What do you think happens to blood flow to your stomach during exercise? What do you think happens to blood flow to your heart during exercise?

Blood Flow Through Organs regulated by nerves & chemical agents both cardiac output & blood vessel diameter controlled by hormones & nerves controlled by ANS increasing blood pressure can increase blood flow increasing blood pressure  increases cardiac output  constricts many arterioles  more blood volume to other organs

Pulmonary Circuit circuit of blood vessels from heart  lungs heart rt ventricle of heart pumps blood thru pulmonary trunk  branches into rt & lt pulmonary arteries  smaller arterioles  capillaries that surround the alveoli (little air sacs) where oxygenation of RBCs & get rid of carbon dioxide

Pulmonary Circuit cont’d from capillaries  venules which merge into larger & larger veins until they merge into the pulmonary veins: 2 pulmonary veins from each lung empty into lt atrium

Remember! Pulmonary Trunk & Pulmonary Arteries carry deoxygenated blood to lungs Pulmonary Veins carry oxygenated blood into left side of heart

Aorta Ascending Aorta rt & lt coronary arteries Aortic Arch begins @ aortic semilunar valve rt & lt coronary arteries supply rt & lt sides of heart Aortic Arch 3 important branches: brachiocephalic trunk, lt common carotid, lt subclavian Descending Aorta travels posterior to heart portion in thorax called thoracic aorta Portion in abdominal cavity called abdominal aorta

Common Carotids branch into: External Carotid arteries supply blood to neck, esophagus, pharynx, larynx, lower jaw, face Internal Carotid arteries supply blood to the brain (with the rt & lt vertebral arteries: branches of subclavian arteries)

Arteries of Upper Extremities Axillary artery: branch of subclavian artery becomes Brachial artery in the arm branches into Radial (pulse)& Ulnar arteries in lower arm

Branches of the Abdominal Aorta descends slightly to the left of the vertebral column retroperitoneal Branches: Celiac Trunk (3 branches) Lt gastric artery: stomach Splenic artery: spleen: stomach, & pancreas Common Hepatic Artery: liver, stomach, gallbladder, & duodenum

Branches of the Abdominal Aorta 2. Superior Mesenteric Artery: pancreas, duodenum, small intestines, most of large intestines 3. Inferior mesenteric Artery: terminal portion of the colon, sigmoid colon, & rectum

Branches of the Abdominal Aorta

5 Paired Arteries from Abdominal Aorta Inferior phrenic arteries inferior surface of diaphragm Suprarenal arteries Adrenal glands Renal arteries kidneys Gonadal arteries Testicular or Ovarian Lumbar arteries vertebrae, spinal cord, abdominal wall

Iliac Arteries Abdominal Aorta branches into rt & lt Common Iliac Arteries @ L4 level each branches  internal & external iliac arteries @ level of lumbosacral joint Internal Iliac Arteries: bladder, external genitalia, uterus, vagina External Iliac Arteries: blood to lower extremities

Iliac Arteries & Branches

External Iliac Arteries when cross over to medial surface of thigh become Femoral Arteries branches to deep femoral & superficial femoral when reaches knee becomes Popliteal Artery where it branches  posterior & anterior Tibial arteries Posterior Tibial Artery divides  Medial & Plantar Arteries

Arteries of the Lower Extremities

Systemic Veins Most veins run parallel to arteries of same name

Superior & Inferior Vena Cava SVC: large vein that receives blood from upper body (head, neck, upper limbs) IVC: large vein that receives blood from the lower body (lower limbs, pelvis, abdomen) both return blood to right atrium

Systemic Veins Internal Jugular descends parallel to common carotid arteries  brachiocephalic veins(just as they merge with the subclavian veins

Veins of the Upper Extremity Radial & Ulnar veins parallel arteries of same name then merge to become Brachial vein  axillary vein  subclavian vein Vein draw blood from: median cubital

Veins of the Abdomen & Pelvis External Iliac veins receive blood from the lower extremities --> join with Internal Iliac veins to form the rt & lt Common Iliac Veins  fuses with the IVC

Veins of Abdomen & Pelvis

Hepatic Portal System Blood leaving the digestive organs by veins is rich in nutrients….instead of returning directly to IVC  heart this blood is shunted to liver first This way liver can store, convert, detoxify, or excrete materials as necessary Hepatic Portal vein enters liver with nutrient rich blood