Circulatory Systems Flashcards
What do some animals need circulatory systems?
Diffusion can only happen over short distances
Get cells what they need and remove their wastes
Distribute heat
Immune system
What are the 3 types of circulatory systems?
- Gastrovascular cavities
- Open circulatory systems
- Closed circulatory systems
What are the 3 things all circulatory systems have?
- Fluid for transportation
- Interconnecting vessels
- A pump to maintain the flow of fluid
Define open circulatory systems
Vessels open into the body cavity
the circulatory fluid = interstitial fluid = haemolymph
Haemolymph under low pressure
Define closed circulatory systems
Blood and interstitial fluid are physically separated
What are the 2 types of closed circulatory systems?
Single circuit (fish) Double circuit (mammals)
What are the features of a single closed-circuit system?
2 chamber heart
Blood passes through the heart once per circuit
BP highest in gills
Swimming helps speed up their slow circulation
What are the two circuits of a double circuit circulatory system?
Pulmonary and systemic
What kind of heart does an amphibian have?
3-chambered (2 atria, 1 ventricle)
What does the pulmonary circuit include for amphibians?
Lungs and skin
What are the 2 points of the cardiac cycle?
- Systole (contraction)
2. Diastole (relaxation)
Does the brain or heart control the heartbeat?
How?
The heart (myogenic) SA node
When is arterial blood pressure the highest and lowest?
Highest: ventricular systole
Lowest: Ventricular diastole
What is the outer layer of arteries made of?
Collagen
How do small and large molecules get through capillaries?
Small: diffusion
Large: pinocytosis
