Post on 27-Dec-2015
Heart and Blood Vessels
Major Arteries and Veins
Subclavian arterySubclavian vein
Jugular veinCarotid arterySuperiorvena cava
Inferiorvena cava
Commoniliac veinCommoniliac artery
Femoral artery
Great saphenous vein
Renal arteryRenal vein
Aorta
Femoral vein
Blood Vessels—Arterial SystemStructure: endothelium, middle, outer layersFunctions
Arteries carry blood away from heartArterioles and precapillary sphincters control
pressureCapillaries exchange nutrients, waste, and
defensive cells between vessel and tissue
Arterioles and Capillaries
Capillary Structure
Blood Vessels—Venous SystemStructure: three layers, thin-walledFunctions: carry blood toward the heartMechanisms in blood return
Contraction of skeletal musclesOne-way valvesPressure changes associated with breathing
Blood Vessels—Venous System
Blood Vessels—Summary
Inner layer:Endothelium
Middle layer:Smooth musclewith elasticfibers
Outer layer:Connectivetissue
Connective tissue
Endothelium
Vein
Venule
Artery
Arteriole
Capillary
Direction ofblood flow
Tissuecells
Epithelial cells ofcapillary endothelium
Smooth muscle
Lymphatic SystemFunction
Maintains blood volumeAlso functions in immune system
StructureBlind-ended capillariesLymphatic vesselsLymph is the circulating fluid
The Heart
Figure 8.7
Superior vena cava
Pulmonarysemilunar valveRight atrium
Right AV valveRight ventricle
Inferior vena cava
Pulmonary trunk
Left pulmonary veins
Left atrium
Left AV valve
Aortic semilunar valve
Chordae tendineae
Papillary muscles
Left ventricle
Septum
Right pulmonary artery
Left pulmonary artery
Aorta
The HeartStructureLayers: epicardium, myocardium, and
endocardiumChambers: two atrias, two ventriclesValves
Two atrioventricular valves: tricuspid and bicuspid (mitral)
Two semilunar valves: pulmonary and aortic
Pulmonary Circuit—Oxygenation of Blood Pathway
Deoxygenated blood from the body into heart1. Through the vena cava to the right atrium2. Through the right atrioventricular valve to the
right ventricle3. Through the pulmonary semilunar valve to the
pulmonary trunk and the lungs
Pulmonary Circuit—Oxygenation of Blood Pathway
Oxygenated blood from lungs to heart1. Through the pulmonary veins to the left atrium2. Through the left atrioventricular valve to the
left ventricle
Systemic Circuit—Delivery of Oxygenated Blood to Tissues
Pathway Oxygenated blood from the heart to tissues
1. Through the aortic semilunar valve to the aorta2. Through branching arteries and arterioles to
tissues3. Through the arterioles to capillaries
Systemic Circuit: Return of Blood to the Heart
Pathway Deoxygenated blood returns to heart
1. From capillaries into venules and veins2. To the vena cava and into the right atrium
Pulmonary and Systemic Circuits
Subclavian arterySubclavian vein
Jugular veinCarotid arterySuperiorvena cava
Inferiorvena cava
Commoniliac veinCommoniliac artery
Femoral artery
Great saphenous vein
Renal arteryRenal vein
Aorta
Femoral vein
Cardiac Cycle
Heart Sounds and Heart ValvesLub-dub (typical heart beat)
Sounds are valves closingHeart murmurs
Cardiac Conduction System Coordinates Contraction
SA node: cardiac pacemaker
AV node: relays impulse
AV bundle and Purkinje fibers: carry impulse to ventricles
Electrocardiograms (EKG/ECG)Measure the electrical impulses of the heartThree formations
P wave: impulse across atriaQRS complex: spread of impulse down septum,
around ventricles in Purkinje fibersT wave: end of electrical activity in ventricles
Arrythmias, ventricular fibrillation can be detected
Electrocardiograms (EKG/ECG) (cont.)
Blood PressureDefinitions
Systolic pressureDiastolic pressure
MeasurementSphygmomanometerWhat’s a “normal” reading? What would be considered “high” or “low”
blood pressure?
How Blood Pressure is Measured
Figure 8.16
Blood Pressure (cont.)Hypertension: high blood pressure
The silent killerHypotension: blood pressure too low
Clinical signs: dizziness, faintingCauses: orthostatic, severe burns, blood loss
Regulation of the Cardiovascular System: Baroreceptors
Baroreceptors: pressure receptors in aorta and carotid arteries
Steps in mechanism1. Blood pressure rises, vessels stretched2. Signals sent to brain in the cardiovascular
center3. Heart signaled to lower heart rate and force of
contraction4. Arterioles vasodilate, increasing blood flow to
tissues5. Combined effect lowers blood pressure
Regulation: Nervous and Endocrine FactorsCentral Nervous System signals
Sympathetic nerves: constrict blood vessels, raising blood pressure
Parasympathetic nerves: dilate blood vessels, lowering blood pressure
Hormones: epinephrine (adrenaline)Local requirements dictate local blood flowExercise: increased blood flow and cardiac
output
Cardiovascular DisordersAngina pectoris: a warning, chest painMyocardial infarction/heart attack:
permanent cardiac damageCongestive heart failure: decrease in
pumping efficiencyEmbolism: blockage of blood vesselsStroke: impaired blood flow to the brain
Reducing the Risk of Cardiovascular DiseaseSmoking: don’t Blood lipids: monitor cholesterol levelsExercise: regular and moderateBlood pressure: treat hypertension
Reducing the Risk of Cardiovascular Disease (cont.)
Weight: being overweight increases risk of heart attack and stroke
Control of diabetes mellitus: early diagnosis and treatment delays onset of related problems
Stress: avoid chronic stress
Cardiac Anatomy Practice