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Biology 250:Human Anatomy. Spring 2005 Cardiovascular System. Blood Flow Through Heart. Blood enters R Atrium from: Superior Vena Cava Inferior Vena Cava Coronary Sinus Travels from R Atrium to R Ventricle: Tricuspid Valve is open Travels from R Ventricle to Lungs
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Biology 250:Human Anatomy Spring 2005 Cardiovascular System
Blood Flow Through Heart • Blood enters R Atrium from: • Superior Vena Cava • Inferior Vena Cava • Coronary Sinus • Travels from R Atrium to R Ventricle: • Tricuspid Valve is open • Travels from R Ventricle to Lungs • Pulmonary Semilunar Valve open • R Pulmonary, L Pulmonary Arteries
Blood Flow Through Heart (Cont.) • Travels from Lungs to L Atrium via: • R Pulmonary, L Pulmonary Veins • Travels from L Atrium to L Ventricle • Bicuspid (Mitral) Valve is open • Travels from L Ventricle to Aorta • Aortic Semilunar Valve is open • Travels from Aorta to rest of body
Cardiac Cycle • Systole • Period of ventricular contraction • Diastole • Period of ventricular relaxation • Ventricles receive blood from atria • Heart Sounds • “Lub-Dub” • 1st sound: closing of AV Valves (Systole) • 2nd sound: closing of Semilunar Valves (Diastole)
Cardiac Output • Heart Rate • Number of heart beats per minute • Stroke Volume • Volume of blood pumped with each beat • Cardiac Output • Amount of blood pumped by each ventricle per l minute • Calculated by heart rate x stroke volume
Common Heart Dysfunctions • Tacycardia: more than 100 beats/minute • Bradycardia: less than 60 beats/minute • Congestive Heart Failure (CHF) • Back-up of blood; inadequate pumping • Peripheral Congestion • Pulmonary Congestion • Myocardial Infarction (MI) • Heart Attack; myocardium dies
Blood Vessels • 3 Major Blood Vessels: • Arteries • Carry blood away from the heart • Veins • Return blood to the heart • Capillaries • Actual site of nutrient, waste exchange
Blood Vessel Structure • 3 Layers of Walls (Tunics): • Tunica Interna (Tunica Intima) • Innermost layer of the blood vessel • Tunica Media • Middle layer of blood vessel • Tunica Externa (Tunica Adventitia) • Outtermost layer of blood vessel
Blood Vessel Structure (Cont.) • Lumen • Central canal of the blood vessel • Portion where the blood actually flows • Vasoconstriction • Reduction of the size (diameter) of the lumen • Vasodilation • Increase of the size (diameter) of the lumen
Arterial System • 3 Types of Arteries: • Elastic (Conducting) Arteries • Large arteries close to the heart • Large lumen, low resistance • Muscular (Distributing) Arteries • Deliver blood to specific body organs • Composed of mainly tunica media • Arterioles • Smallest of arteries; interact with capillaries
Capillaries • 3 Types of Capillaries: • Continuous Capillaries • Abundant in skin and muscles • Fenestrated Capillaries • Found where filtration, absorption are required • Sinsusoidal Capillaries • Very leaky, found in liver, bone marrow
Venous System • Venules • Smallest veins; interact with capillaries • Join together to form veins • Veins • Contain very large lumens • Contains virtually no smooth muscle • Venous Valves • Varicose Veins • Deep Vein Thrombosis (DVT)
Pulse / Blood Pressure • Pulse: expansion of arteries w/ each beat • Pressure Points • Blood Pressure • Systolic: 1st number (100-140mm Hg) • Diastolic: 2nd number (75-80mm Hg) • Hypotension: systolic BP < 100mm Hg • Hypertension: systolic BP > 140mm Hg
Major Arteries • Upper Body • Carotid Artery • Vertebral Artery • Aorta • Brachial Artery • Radial Artery • Ulnar Artery
Major Arteries (Cont.) • Lower Body • Abdominal Aorta • Iliac Artery • Femoral Artery • Popliteal Artery • Anterior Tibial Artery • Posterior Tibial Artery • Dorsalis Pedis Artery