Circulation Cardiovascular System = Heart, Blood and Vessels Lymphatic System = Lymph nodes, Organs and Vessels

The Lymphatic Vessels Function: to collect excess tissue fluid collecting at arteriole end of capillary beds, and return leaked blood proteins to blood (maintain osmotic pressure needed to take up water into bloodstream) Lymph is moved through vessels Pulse of nearby arteries Contraction of surrounding skeletal muscle Regular movement of body (wiggling legs) Muscle in Tunica Media

Lymphatic System…The Players: Lymph- clear fluid from loose CT at capillaries Contains small molecules of blood plasma, water, various ions, nutrient molecules, respiratory gases Lymphatic capillaries (near blood capillaries)  Lymph collecting vessels (small, 3 tunicas, # valves) Lymph nodes (sit along collecting vessels)-clean lymph of pathogens, they are NOT glands Lymphatic trunks (convergence large collecting vessels) Lymphatic ducts  empty into veins of neck

Lymphatic Ducts Thoracic Duct Receives lymph from large trunks in abdomen and thorax Receives lymph from ducts of thoracic lymph nodes Along vertebral bodies Contain valves to ensure 1-way flow of lymph to lymph nodes Drains into left Brachiocephalic Vein (or subclavian or int. jugular veins) pg 154

Functions of Heart and Cardiovascular System Bulk flow of blood Exchange with tissue Heart Right side receives oxygen-poor blood from body tissues and pumps the blood to the lungs Left side receives the oxygenated blood from the lungs and pumps the blood throughout the body

Location of Heart in Chest Oblique Position Apex = Left of Midline (5th ICS), Anterior to rest of heart Base (posterior surface) sits on vertebral column Superior Right = 3rd Costal Cartilage, 1” right midsternum Superior Left = 2nd Costal Cartilage, 1” left midsternum Inferior Right = 6th Costal Cartilage, 1” right midsternum Inferior Left = 5th Intercostal Space at Midclavicular line Pg 178

Cardiac Conduction Intrinsic system initiating and coordinating contraction of heart muscle Sinoatrial node (where SVC enters RA) Atrioventricular node (in atrioventricular septum) AV Bundle (in IV septum then splits) Purkinje fibers (throughout LV) Cardiac Plexus (external innervation) Vagus (parasympathetic) Sympathetic trunk pg 201

Blood Flow to Supply the Heart Muscle Heart wall too thick for diffusion of nutrients Rt and Lft Coronary Arteries Branch from Ascending Aorta Have multiple branches along heart Sit in Coronary Sulcus Coronary Heart Disease Cardiac Veins Coronary Sinus (largest) Many branches feed into sinus Sits in Coronary Sulcus pg 193

Pericardium Pericardium (3 layers) Pericardial Cavity pg 177 1) Outer-fibrous pericardium Serous pericardium 2) parietal 3) visceral (epicardium) Pericardial Cavity between layers of serous pericardium serous fluid lubricate heart while beating

External Features of Heart Interventricular sulcus Coronal/Coronary sulcus Auricles of atria Apex Base Coronary vessels Ligamentum Arteriosum Pg 181

The Great Vessels and major branches Aorta (from Left Ventricle) Ascending Coronary arteries Aortic Arch Brachiocephalic trunk Left Common Carotid Left Subclavian Descending (Thoracic/Abdominal) Many small branches to organs Pulmonary Trunk (from Rt Ventricle) -2 Pulmonary Arteries into lungs Inferior/Superior Vena Cava - Coronary sinus Pg 203

Layers of Heart Epicardium (most superficial) – Visceral serosa Myocardium (middle layer) Cardiac muscle Contracts Endocardium (inner layer = lining) Endothelium on CT Lines the heart Creates the valves Pg 190

Fibrous Skeleton of Heart Insertion for cardiac muscle Anchors valve cusps Prevents valves from opening too much Block electrical impulses from atria to ventricles Contains AV node Pg 192

Heart Chambers 2 receiving chambers: 2 pumping chambers: Right atria Left atria 2 pumping chambers: Right ventricle Left ventricle Atria are superior to ventricles Arrangement is not linear…it’s twisted!

Right Heart Chambers: Pulmonary Pump pg 186, 188 Right Atrium (forms most of base of heart) Receives O2-poor blood from body via IVC, SVC, Coronary sinus Ventral wall (w/Pectinate muscles) and dorsal wall (no pectinate muscles) separated by crista terminalis Fossa Ovalis- on interatrial septum, remnant of Foramen Ovale Right Ventricle Receives O2-poor blood from right atrium through tricuspid valve Trabeculae Carnae- muscle ridges along ventral surface Chordae Tendinae-fibrous cords running between AV valve cusps and papillary muscles Papillary Muscles (3)-cone-shaped muscles within ventricles to which chordae tendinae are anchored Moderator Band (septomarginal trabecula)-muscular band connecting anterior papillary muscle to interventricular septum Pumps blood to lungs via Pulmonary Semilunar Valve in pulmonary trunk

Left Heart Chambers: Systemic Pump Left Atrium Receives O2-rich blood from 4 Pulmonary Veins Pectinate Muscles line only auricle Left Ventricle (forms apex of heart) Receives blood from Left Atrium via bicuspid valve Same structures as Rt Ventricle: Trabeculae carnae, Papillary muscles (2), Chordae tendinae No Moderator band Pumps blood into aorta via Aortic Semilunar Valve to body pg 189, 190

Heart Valves: Lub*-Dub** *Tricuspid Valve: Right AV valve 3 Cusps (flaps) made of endocardium and CT Cusps anchored in Rt. Ventricle by Chordae Tendinae Chordae Tendinae prevent inversion of cusps into atrium Flow of blood pushes cusps open When ventricle is in diastole (relaxed), cusps hang limp in ventricle Ventricular contraction increases pressure and forces cusps closed *Bicuspid (Mitral) Valve: Left AV valve 2 cusps anchored in Left Ventricle by chordae tendinae Functions same as Rt. AV valve They close together pg 188

Semilunar Valves (the dub) pg 191 Semilunar valves: prevents backflow in large arteries Pulmonary Semilunar Valve Right Ventricle and Pulmonary Trunk Aortic Semilunar Valve Left Ventricle and Aorta Made of 3 Cusps As blood rushes past the cusps are flattened As it settles they’re pushed down (valve closed)

Flow of Blood O2-poor blood (S+I VC, Coronary Sinus) enters Rt Atrium Travels through Tricuspid Valve into Rt Ventricle Pumped out through Pulmonary Semilunar Valve into Pulmonary trunk (branches into Pulmonary Arteries) and to lungs After circulating through lungs, O2-rich blood returns to the heart through 4 Pulmonary veins The O2-rich blood enters the Left Atrium Travels through Bicuspid/Mitral Valve into Left Ventricle Pumped out through Aortic Semilunar Valve into Aorta to be distributed to rest of body by descending aorta and branches of aortic arch

Cardiovascular Flow of Blood HeartArteries(conducting-distributing) ArteriolesCapillaries of tissues At Capillaries O2 is delivered and CO2 picked up CapillariesVenulesVeinsHeart

Circuits Pulmonary Circuit Systemic Circuit Vessels carrying blood to and from lungs Pulmonary arteries and veins Systemic Circuit Vessels carrying blood to and from the rest of the body All other vessels pg 185

Blood Vessels Powered by the heart! Carry blood to and from the heart 3 main types: Arteries Carry blood away from heart arterioles Capillaries Veins Carry blood toward heart Venules

Anatomy of Arteries and Veins Tunica externa Outermost layer CT w/elastin and collagen Vaso Vasorum Tiny arteries, veins, capillaries on vessels to nourish them (outer half) Protects, Strengthens, Anchors Tunica media Middle layer Circular Smooth Muscle Collagen & Elastic Fibers Vaso-constriction/dilation Tunica intima Innermost layer Endothelium Minimize friction Lumen Anatomy of Arteries and Veins www.histology-world.com/keyfeatures/vessels1.htm

Vessels of Cardiovascular System: Arteries Carry blood AWAY from heart Systemic Circuit: carry O2 blood Pulmonary Circuit: carry de-O2 blood Walls thicker than Veins Tunica media > Tunica externa 3 Types Conducting (elastic) large, elastin, high pressure Distributing (muscular) medium size, to organs Arterioles smallest

Capillaries Smallest blood vessels Lumen is typically only 1 RBC thick Only 1 endothelial cell layer surrounded by basal lamina (no tunica media or externa) Deliver O2 and nutrients to cells and remove waste Capillary Beds: networks of capillaries Regulating amount of blood going to cells throughout tissues Supply tissues and organs that otherwise have poor capillary circulation Epithelium, cartilage has no capillaries

Vessels of Cardiovascular System: Veins Carry blood from capillaries INTO the heart Systemic Circuit: O2 poor blood Pulmonary Circuit: O2 –rich blood Pressure in Veins less than that in arteries Thinner walls than arteries (tunica externa > tunica media, less elastin) Larger lumen than arteries Contain valves (made of T. intima) Normal movement, Muscular contraction push blood through Venules- smallest veins

Cardiovascular Blood Flow Portal System: Special vascular circulation where blood goes through 2 capillary beds before returning to the heart to achieve 2nd function (eg) Hepatic Portal System: aids digestion by picking up digestive nutrients from stomach + intestines and delivers to liver for processing/storage Pick-up occurs at capillaries of stomach and intestine Via Hepatic Portal Vein goes to capillaries of liver Via Hepatic Vein blood goes back to heart pg 338

Vascular Anastomoses Vessels unite and connect Arterial Anastomoses Communication between arteries Joints, Abdominal Organs, Brain, Heart Venous Anastomoses Communication between veins More common (eg) back of hand pg 770

Fetal Circulation All major vessels in place by third month 2 main differences: 1. Fetus must supply blood to placenta 2. Lungs do not need much blood because respiratory organ is the placenta www.medical-illustrator.co.uk

1. Blood to Placenta Umbilical vessels Run in umbilical cord 2 umbilical arteries Carry blood (little oxygen and waste) to placenta 1 umbilical vein Returns this blood (with oxygen and nutrients) to fetus and to portal vein (to liver)

2. Bypassing the Lungs: Foramen Ovale pg 186 2. Bypassing the Lungs: Foramen Ovale www.nmtmedical.com/heartrepair.aspx?id=78 Hole in the inter-atrial septum Allows blood to flow from RA to LA Bypasses the RV Would usually bring blood to lungs Becomes the fossa ovalis postnatally

2. Bypassing the Lungs: Ductus Arteriosus Carries blood from pulmonary trunk to aortic arch Empties distal to coronary arteries This enables the heart and brain to receive the most highly oxygenated blood Bypasses the lungs Becomes the ligamentum arteriosum postnatally www.wellesley.edu/.../Courses/111/mammalian.html

First Breath!! Lungs inflate Ductus arteriosus constricts and closes Oxygenated blood begins pouring into LA for first time Raises the pressure within the LA This pushes the 2 flaps of foramen ovale together and closes it