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Circulatory Systemcirculatory system
circulatory sustem2
Vocabulary
• Brady- slow• Tachy- fast• Diastol- dilation
• -gram- written• -syn-together• Systol- contraction
Functions
• To take oxygen and nutrients to all parts of the body• To take carbon dioxide and waste products out of
the body
2 Pathways
• Pulmonary- sends oxygen-depleted blood to the lungs to pick up oxygen• Systemic- sends oxygenated blood and nutrients to
the body and removes waste
Heart
• Pericardium- the membrane that encloses the heart• Parietal Pericardium- inner lining of the
pericardium• Visceral Pericardium- innermost layer surrounding
the heart
Layers of the heart muscle
• Epicardium- outer layer• Protects the heart by reducing friction
• Myocardium- cardiac muscle- Pumps blood out of the heart• Endocardium- inner layer of the heart- Contains
blood vessels and purkinje fibers
Chambers of the heart
• Atria- upper chambers; receive blood returning to the heart• Ventricles- lower chambers; receive blood from the
atria and force blood out into the arteries
Chambers of the heart
• Septum- a solid wall-like structure separating the atria and ventricles so that blood from one side never mixes with the other side• Atrioventrical valve (AV valve)- ensures one way
blood flow between atria and ventricles
Blood supply to the heart
• Coronary Arteries- supply blood to the heart• Cardiac Veins- drain blood from the heart
Pathways • Veins and venuoles- bring deoxygenated blood
from the body to the heart• Arteries and capillaries- bring oxygen-rich blood to
body parts
Heart Sounds• Valves closing (lubb-dupp)• Lubb: ventricular contraction• Dubb: ventricular relaxation
Sanode
• Sinoatrial Node- pacemaker of the heart• Nerve cells touch so impulse spreads easily across
the heart• Average 78 BPM in adults
Purkinje Fibers
• Purkinje fibers- cardiac muscle fibers that conduct nerve impulses• Electrocardiogram (ECG)- a record of the electrical
changes in the heart
Heart beat
• Tachycardia- irregularly fast heart beat 100+ beats per minute• Bradycardia- reduced heart rate fewer than 60
BPM
Blood vessels
• Vasoconstriction- (contract) reduced diameter of blood vessels• Vasodilation- (relaxed) increased diameter of blood
vessels
Blood Pressure
• Systolic Pressure- maximum contraction of ventricles• Diastolic Pressure- when the ventricles are at their
lowest and are about to contract again• Sphygmomanometer- instrument used to measure
blood pressure
Influence of BP
• Blood volume- 5 liters is normal• Peripheral resistance- friction between blood and
blood vessels• Blood viscosity- how resistant blood is to flowing• High viscosity = slow flow• Low viscosity = fast flow* Blood cell count and plasma change blood viscosity
Blood Pressure
• Hypertension = high blood pressure• Consequences- myocardium thickens, enlargement of
heart• Causes- obesity, diet (salt), heart disease, kidney
disease, psychological stress