Circulatory System Flashcards
How do small aquatic invertebrates obtain oxygen?
Diffusion through gastrovascular cavities.
Describe what open circulatory systems are and which organisms have them?
- No distinction between tissue fluid and blood = haemolymph
- Fluid squeezed through intercellular spaces by animal movement + muscular pump (tubular heart)
- e.g. insects.
Describe closed circulatory systems.
- Blood separate from blood
- Muscular pump (heart)
- Some blood components never leave vessels.
What are the advantages of circulatory systems?
- Blood flows through vessels than intracellular spaces
- Possible to selectively direct blood to specific areas
- Transport facilitating molecules can be kept within vessels
> Support higher level of metabolic activity.
What are the components of blood?
- Red blood cells
- White blood cells
- Platelets
- Plasma.
Describe red blood cells.
- Otherwise known as Erythrocytes
- Biconcave
- Have haemoglobin.
Describe the structure of haemoglobin.
- 2 alpha subunits
- 2 beta subunits
- Each has a haem (Fe) group
- Cooperative binding of oxygen.
What blood vessels make up the vascular system?
- Arteries
- Veins
- Capillaries.
Describe arteries and arterioles.
- Move blood away from heart
- Usually oxygenated
- Walls made of elastin and smooth muscle.
Describe veins and venules.
- Take blood to heart (except hepatic portal vein (liver))
- Usually deoxygenated
- Low pressure blood - moving against gravity.
Describe capillaries.
- Thin permeable walls
- Adjacent to all body cells
- Small diameter but huge number = slow blood flow
- Leaky - fenestrations
- Blood pressure squeezes out water and some solutes on arterial side
- Proteins and other solutes create osmotic potential - draws water back in on venous side
- Differentially selective.
Describe lymphatic vessels.
- Some tissue fluid not drawn back into capillaries
- System of blind-ended vessels
- Merge into larger vessels, drain into superior vena cava
- Lymph nodes
- Skeletal muscle movement.
Define atria.
Smaller chamber that blood initially returns to.
Define ventricles.
Larger chamber that collects blood and pressurises it.
Define pulmonary artery.
Takes blood to lungs.
Define pulmonary vein.
Returns blood from lungs.
Define aorta.
Takes blood to body.
Define Vena cava.
Returns blood from body.
What are pace maker cells?
Cells found in cardiac muscle which ensures the heart beats at the correct rhythm at that each cardiac muscle cells coordinates with each other i.e. beats at the same time.
How do pacemaker cells create their own action potentials?
Leaky membranes allow sodium to move in to cells and potassium to move out without any external triggers.
Define diastole.
Relaxing of the heart.
Define systole.
Compressing of the heart.
Define end-diastolic volume (EDV)?
Maximum amount of blood in ventricles at end of ventricular relaxation.
Define isovolumic ventricular contraction.
First phase of ventricular contraction pushes AV valves closed but does not create enough pressure to open semilunar valves.
