Post on 19-Mar-2016
description
The Circulatory System
The Circulatory System
Major Function TRANSPORTATION Helps maintain homeostasis
within the body
Two sub-divisions Cardiovascular system Lymphatic system
The Cardiovascular System
Consists of: Blood
Transporting fluid Heart
Pumps the blood Carries the blood
Arteries, veins, capillaries
The HeartHeart wall has 3 layers
Epicardium, myocardium, endocardium
Made of cardiac muscle Rich in mitochondria
Four chamber Two Atria – upper chambers
Pumps blood to the ventricles Two Ventricles – lower chambers
Left pumps blood to the entire body Right pumps blood to the lungs
Blood Flow in the Heart Oxygen-poor blood enter through the superior & inferior
venae cavae into the right atrium Passes down through the tricuspid valve to the right
ventricle. Passes out the pulmonary trunk arteries to the lungs &
gas exchange occurs. Oxygen-rich blood returns via the pulmonary veins &
passes into the left atrium. Flows down through the bicuspid valve or mitral valve to
the left ventricle. Oxygen-rich blood then flows out the aorta to the body
tissues.
http://www.youtube.com/watch?v=Rj_qD0SEGGk
Physiology of the Heart
Heartbeat & Heart Sounds Two phases of the heartbeat
Diastole (relaxation) Occurs when the ventricle walls relax & blood flows into the
heart from the venae cavae & pulmonary veins Tricuspid & mitral valves open; pulmonary & aortic valves close
Systole (contraction) Walls of right & left ventricles contract; pumping blood into the
pulmonary artery & aorta Tricuspid & mitral valves are closed, preventing backflow
Physiology of the Heart Closure of the valves is associated with audible sounds
“lubb-dubb” “Lubb” associated with closure of the tricuspid & mitral valves at
the beginning of systole “Dubb” closure of the aortic & pulmonary valves at the end of
systole Murmur
Abnormal swishing sound http://www.dundee.ac.uk/medther/Cardiology/audio/norm
al.wav
http://www.dundee.ac.uk/medther/Cardiology/audio/ms.wav
Physiology of the Heart Conduction System
Sinoatrial Node (SA Node) (pacemaker)
Specialized muscle tissue that initiates the heartbeat Wave of electricity passes to another region of the
myocardium (within the interatrial septum) to the Atrioventricular node (AV node)
AV node sends excitation wave to atrioventricular bundle (bundle of His)
Bundle divides into the left bundle branch & right bundle branch
Physiology of the Heart
Electrocardiogram (ECG or EKG) Record used to detect the electrical changes in the
heart muscle
Blood Vessels
Arteries Large blood vessels that carry blood away from the
heart Lined with connective tissue, muscle, tissue, elastic
layer, & endothelium (innermost layer) Strong to withstand high pressure pumping from the
heart Arterioles
Smaller branches of arteries Thinner & carry blood to capillaries
Blood Vessels
Capillaries One endothelial cell thick Carry nutrient-rich, oxygenated blood from the
arteries & arterioles to the body cells Pick up waste products (i.e. CO2) & flow back to
the small venules, which combine to form larger vessels called the veins.
Blood VesselsVeins
Thinner walls compared with arteries Take blood toward the heart Have valves to prevent the backflow of blood
Blood Pressure Blood moves through our Circulation System because it is
under Pressure. caused by the Contraction of the Heart and by Muscles that
surround Blood Vessels. Blood Pressure is Always highest in the Two Main Arteries that
leave the Heart. Maintained by TWO WAYS:
(1) The Nervous System, which can speed up or slow down the Heart Rate;
(2) The KIDNEYS, which regulate blood pressure by the amount of fluid in our Blood.
When pressure is too high, kidneys remove water from blood, lowering the total amount of fluid in the Circulatory System. Both High and LOW Blood Pressure can cause our bodies problems.
Blood PressureUsually Measured in the Artery Supplying the
upper Arm. Measured by a sphygmomanometer
Systolic Blood Pressure force of blood recorded during ventricular
contractionDiastolic Blood Pressure
force of blood reordered during ventricular relaxation
Average blood pressure = 120/80 mm Hg
Factors Affecting Blood Pressure
Neural FactorsRenal Factors – KidneysTemperatureChemicalsDietAge & WeightExerciseEmotional State
Cardiac DisordersRisk factors of heart disease
High blood pressure, high blood cholesterol, cigarette smoking, obesity, lack of exercise, diabetes mellitus, and genetics.
Immediate Causes of Heart Disease Inadequate blood supply, anatomical disorders,
arrhythmiasCHF – Congestive Heart Failure
Heart cannot meet the body’s oxygen demands
The Lymphatic System Consists of lymphatic vessels,
lymph nodes, & lymph organs. Supports both Cardiovascular
System & the Immune System. Functions:
Picks up fluid leaked from the blood vessels & returns it to the blood.
Disposes of debris in the lymphatic stream
Houses WBCs involved in immunity
Lymphatic Vessels
Picks up excess tissue fluid called lymph, & returns it to the bloodstream. Fluid accumulation in tissues can cause edema, which
impairs blood-to-tissue exchange One-way system towards the heart Lymph capillaries absorb fluid in tissues Enters the venous system through two large ducts
Right lymphatic duct Thoracic duct
Lymph Nodes Removes foreign material
from the lymphatic stream by producing lymphocytes (WBCs) that function in immune response.
Act as tiny filters Contain macrophages that
engulf & destroy bacteria Swollen glands are a result
of trapping substances in the nodes.
Other Lymphoid Organs
Spleen Filters blood & destroys worn-out RBCs & returns
the breakdown products to the liverThymus
Produces hormones that program lymphocytes (immune system cells)
Tonsils Masses of lymphoid tissue embedded in mucus Trap any foreign material entering the throat.
http://www.youtube.com/watch?v=Kh-XdNnTZUo