EXS111 Circulatory System Lecture Objectives PDF

Circulatory System Lecture Objectives Know the two systems that make up the circulatory system 1. Cardiovascular System 2. Lymphatic System Describe the functions and composition of blood. blood function Transport medium for ○ Nutrients, signaling molecules, respiratory ga...

Circulatory System Lecture Objectives Know the two systems that make up the circulatory system 1. Cardiovascular System 2. Lymphatic System Describe the functions and composition of blood. blood function Transport medium for ○ Nutrients, signaling molecules, respiratory gases, waste products Stabilizes pH and electrolytes Prevents fluid loss – clotting Defense composition Cellular and liquid components ○ Specialized connective tissue Blood cells – formed elements Plasma – liquid portion of blood 1. Plasma 2. Buffy Coat – Leukocytes and Platelets 3. Erythrocytes blood plasma Straw-colored, sticky fluid portion of blood About 90% water (least dense component of blood) Contains more than 100 kinds of molecules ○ Na+ and Cl- ions ○ Nutrients (sugars, amino acids, lipids) ○ Wastes (carbon dioxide, ruea, ammonia) ○ Proteins (fibrinogen, albumin, globulin) Fibrinogen: molecule involved in chemical reactions for blood clotting Albumin: prevents water from diffusing out of blood vessels Globulins: antibodies and blood proteins that transport lipids, iron, and copper erythrocytes - red blood cells Oxygen-transporting cells No organelles or nuclei  Packed with hemoglobin ○ Bears 4 chains of amino acids ○ Each amino acid bears an iron and 4 heme molecules which bind with an oxygen molecule ○ Oxidation of iron atoms of the hemoglobin molecules gives blood its red color Pick up O2 at lung capillaries – external respiration Release O2 across other tissue capillaries – internal respiration leukocytes - white blood cells Protect body from infectious microorganisms Function outside the bloodstream in loose connective tissue 2 types ○ Granulocytes neutrophils, eosinophils, basophils ○ Agranulocytes lymphocytes and monocytes Describe the importance of blood circulation. Powered by the pumping action of the heart ○ Oxygen and nutrients diffuse across capillary walls to tissues ○ Transport hormones from endocrine glands ○ Convey cells of immune system ○ Regulates blood temperature – thermoregulation Explain the difference between and open and closed circuit. open circuit: a body system that is exposed to the external environment The respiratory is open because air (external substance) is coming into your GI system; you bring food (external substance) into your body through your mouth closed circuit: is a body system that, under normal circumstances, should not be exposed to the external environment. circulatory system is a closed circuit, because under normal circumstances, vessels/blood does not ever come in contact with anything external. Arterial Circulation – carries blood away from the heart; high pressure Venous Circulation – carries blood towards the heart; low pressure Define the Systemic, Pulmonary, and Portal circulatory systems and their functions. pulmonary circuit – right side receives oxygen-poor blood from the body and pumps it to the lungs systemic circuit – left side receives oxygenated blood from the lungs and pumps throughout the body Systemic Arteries ○ Branch directly or indirectly from aorta Aorta = largest artery in the body ○ Carry oxygenated blood away from the heart ○ High pressure vessels ○ Major arteries in neck and limbs run deep so bones and muscles can help protect them Systemic Veins ○ Often run alongside arteries and given similar names ○ Low pressure ○ More variable ○ Empty into vena cavas or coronary sinus ○ Superficial and deep veins ○ Temperature control hepatic portal system Venous system draining the capillary bed in the intestines to the capillary bed in the liver Digested contents are “processed” in the liver before being released into systemic circulation ○ Proteins, fats, alcohols, toxins, etc One of the ways the liver “filters” blood portal circuit Aorta & Vena Cava aorta Ascending Aorta: arises from left ventricle ○ Branches – right and left coronary artery Aortic Arch: lies posterior to manubrium ○ Branches brachiocephalic trunk ○ Left common carotid ○ Let subclavian artery Descending Aorta: continues from aortic arch ○ Thoracic Aorta – T5 - T12 ○ Abdominal Aorta – ends at L4 Divides into left and right common iliac arteries vena cava Superior (To Right Atrium) ○ Head ○ Upper limbs ○ Thorax Inferior (To Right Atrium) ○ Abdomen ○ Liver ○ Pelvis/Perineum ○ Lower Limb Know the major arteries and veins in the thorax, abdomen, and pelvis. Specifically, know which arteries and veins connect head and extremities to the thorax and pelvis. upper limb arteries Originates of the aortic arch (brachiocephalic trunk) ○ Subclavian (neck) Axillary (armpit) Brachial (arm) ○ Forearm – ulna and radius major arteries of the head Common Carotid ○ External Carotid to Face and Scalp ○ Internal Carotid To Brain major arteries of the lower limb Common Iliac ○ Internal Iliac Into Pelvis ○ External Iliac Into … Femoral, Popliteal, Anterior and Posterior Tibial veins of head Internal Jugular ○ From the Brain External Jugular ○ From the Face and Scalp veins of the upper limb Deep Veins ○ Follow the paths of companion arteries ○ Have the same names as the companion arteries Superficial Veins ○ Visible beneath the skin Cephalic Vein Basilic Vein Median Cubital Vein Median Vein of the Forearm veins of the abdomen – tributaries of the inferior vena cava Lumbar Veins Gonadal Veins Renal (kidney) Veins Suprarenal Veins  Hepatic (liver) Veins veins of the pelvis and lower limb Deep Veins ○ Share the name of the accompanying artery Superficial Veins ○ Great saphenous vein empties into the femoral vein ○ Small saphenous vein empties into popliteal vein Describe the physical features of arteries and veins and the differences in the quality of blood flowing through each. blood vessels - types major: Arteries, Capillaries, Veins Arteries: carry blood away from heart Arterioles: ○ the smallest arteries ○ Larger arterioles possess all 3 tunics ○ Diameter controlled by local factors in tissues or sympathetic nervous system Capillaries: smallest blood vessels Veins: receive blood from venules ○ Conduct blood from capillaries toward the heart ○ Blood pressure is lower than in arteries ○ Venules join to form veins Venules: smallest veins ○ Receive blood from capillaries ○ Smallest venules = Postcapillary venules structure of blood vessels Lumen: central blood-filled space of vessel 3 layers/tunics of blood vessels 1. Tunica Intima Innermost tunic Contains endothelium ○ Simple squamous epithelium ○ Vessels > 1mm also have a subendothelial layer 2. Tunica Media Sheets of smooth muscle ○ Contraction – vasoconstriction ○ Relaxation – vasodilation 3. Tunica Externa a. Composed of connective tissue differences  veins’ structural differences from arteries ○ Lumens are larger 65% of the body's blood in veins at any given time ○ Tunica externa is thicker ○ Less elastin in walls ○ Walls are thinner than those of comparable arteries Describe the function and importance of capillaries. Capillaries – Smallest Blood Vessels Red blood cells pass through single file Site-specific functions of capillaries ○ Lung: oxygen enters blood, carbon dioxide leaves ○ Small intestines: receive digested nutrients ○ Endocrine glands: pick up hormones ○ Kidneys: remove of nitrogenous wastes Continuous Capillaries ○ Most common type ○ Occur in most organs ○ Epithelial cells joined by tight junctions and desmosomes ○ Intercellular clefts Gaps of unjoined membranes that allow small molecules in/out of capillaries Fenestrated Capillaries ○ Epithelial cells joined by tight junctions and desmosomes ○ Have pores in endothelium ○ Occurs where high rates of exchange occur Small intestine Glomeruli of kidneys Endocrine glands Sinusoid Capillaries ○ Wide, leaky capillaries = most permeable Usually fenestrated Intercellular clefts are wide open ○ Occur in liver, bone marrow, and spleen Sinusoids have a large diameter and twisted course capillary permeability Direct diffusion Intercellular Clefts Fenestrations Pinocytotic Vesicles capillary beds Network of capillaries running through tissues Precapillary sphincter ○ Regulate the flow of blood to tissues Tendons & ligaments – poorly vascularized  Epithelia & cartilage – avascular ○ Receive nutrients from nearby connective tissue MISC types of arteries Elastic (largest) – sometimes called “conducting arteries” ○ Aorta and its major branches (brachiocephalic trunk, L common carotid, L subclavian) ○ High elastin contest dampens surge of blood pressure Muscular – sometimes called “distributing arteries” ○ Includes most arteries ○ Tunica media = thick ○ Contains internal and external elastic membrane