Biology
Circulation
Terms
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- Gastrovascular cavity
- due to one cell thick width, can diffuse nutrients across instead of having to have a circulatory system (cnidarians and flatworms)- no true system
- True circulatory system
- muscular pump (heart), circulatory fluid (blood), and tubes/vessels to carry blood
- Open circulatory system
- (arthropods and mollucs) fluid pumped through open ended vessel and flows out among cells (no distinction between blood and interstitial fluid)
- Closed circulatory system
- blood in vessels (distinct from interstitial fluid
- types of vessels
- arteries (away from heart to organs/tissues) veins (return to heart) capillaries (convey blood between arteries and veins in tissue)
- Fish circulatory system
- blood pumped in single circuit (gill capillaries to systemic capillaries to heart)
- Evolved circulatory system
- double circulation! blood pumped twice; more rigorous blood flow to get blood through lung capillaries
- pulmonary circuit
- blood between heart and gas exchange in lung tissue
- systemic circuit
- blood between heart and rest of body
- 3 chambered vs 4 chambered hearts
- 3 chambered hearts: mix of oxygen/deox blood in undivided ventricle (frogs and other amphibians) 4 chambered heart: no mix of oxygen/deox blood
- Heart valves
- cardiac valves open passively when upstream pressure is greater than downstream pressure
- lub dub
- lub= recoil of blood against closed AV valves dub=recoil of blood against semilunar valves
- diastole
- heart relaxed, blood flows into atrium and ventricles av valves open
- systole
- heart contracts; atria contract, flow into ventricles ventricles contract, av valves close, semilunar open and blood flows into arteries WHILE blood flowing into atria
- pacemaker
- sets rate that cardiac muscles contract by setting an electrical signal in atria
- atrioventrical node
- relays signals to ventricles
- echocardiagram
- electrical signal changes in heart (combo of electrical charges in cells)
- defibrillator
- reset the rhythm of heart by changing electrical impulses
- atheroclerosis
- gradual impairment of arteries due to chronic condition plaque buildup, reduces bloodflow
- heart attack
- damage to cardiac muscle usually resulting from blocked coronary arteries
- blood vessels
- molecules diffuse out of capillary walls and into interstitial fluid before going to tissues
- sphincters smooth muscle
- regulates distribution of blood to capillaries and organs sphincters in capillaries at entrance of capillary beds open/close depending on need for oxygen/blood
- arteries and veins
- lined by single layer of epithelial cells smooth muscle cell walls (control blood flow) elastic fibers permit recoil after stretching in systole
- blood pressure
- random muscle contractions squeeze veins to keep blood flowing creating pressure
- Erythropoietin
- Hormone regulates RBC production, produced by kidney
- anemia
- abnormal amount of RBC/hemoglobin fatigue due to lack of oxygen in tissues