Transport In Animals Flashcards
Why do multicellular organisms require transport system
Small surface area to volume ratio, high metabolic rates
Demand for oxygen is high
Summarise the different types of circulatory system
Open - blood can diffuse out of vessels
Closed-confined to vessels
blood passes through pump once per circuit
Double - blood passes through the heart twice per circuit of body
Define structures of arteries
Thick,muscular walls to handle high pressure
Elastic tissue to allow recoil
Narrow lumen
Define structure for veins
Thin walls - low pressure
Valves to ensure blood doesn’t flow backwards
Define structure of capillaries
One cell thick walls - short diffusion pathway
Very narrow
Numerous and highly branched
What is tissue fluid
Liquid substance, supplies to the cells while removing any waste materials
What types of pressure influence formation of tissue fluid
Hydrostatic pressure- higher at arterial end of capillaries then venous end
Osmotic - changing water potential of the capillaries as water moves out
How is tissue fluid formed
Blood pumped through increasingly small vessels
Hydrostatic pressure >oncotic pressure
So they move out of capillaries
What is the structure and function of arterioles
S-branch off arteries, feed blood into capillaries
What is the structure and function of Venules
Larger then capillaries but smaller then veins
How does tissue fluid differ from blood and lymph
Tissue fluid is formed from blood
No contain - platelets, erythrocytes and other solutes
Tissue fluid bathed - lymph, less oxygen and nutrients with more waste products
Describe what happens during cardiac diastole
Heart relaxed
Blood enters atria ,increase pressure, pushes open ATRIOVENTRICULAR valves
Pressure in the heart < arteries
Semi lunar valves remain closed
Describe what happens during atrial systole
Atria contract
Pushing any blood into ventricles
Describe what happens during ventricular systole
Ventricles contracts
Pressure increases,closing atrioventricular valves to prevent back flow
Open semi lunar valves
Blood flows into arteries
How do you calculate cardiac output
Heart rate x stroke volume
Explain how the heart contracts
Sally Always Aims Balls Past Vicky SAN-initiates AVN -delays Bundle of His Purkinje fibres Ventricular contraction
What is an electro diagram
Graph showing the amount of electrical activity in the heart during cardiac cycle
Describe abnormal activity that may be seen on an ECG
Tachycardia-fast heart beat
Bradycardia -slow heartbeat
Fibrillation -irregular, fast heartbeat
Ectopic -early or extra heartbeats
What is due role of haemoglobin
S-quaternary structure,4 polypeptide chains, 4 haem groups (iron)
Oxygen molecules bind to haem group
Released in respiring tissues
How does partial pressure of oxygen affect oxygen-haemoglobin
Partial pressure increases
Affinity of haemoglobin for oxygen also increases
What do oxyhemoglobin dissociation curves show
Saturation of haemoglobin with oxygen
Plotted against partial pressure of oxygen
Curves to left to show haemoglobin has a higher affinity for oxygen
Describe the Bohr effect
As CO2 increase, conditions became acidic -haemoglobin changes shape
Affinity decreases so o2 is released
Explain the role of CARBONIC ANHYDRASE in the Bohr effect
Carbonic anhydrase present in RBC
Converts CO2 -> carbonic acid, which dissociates to produce H+ ions
H+ haemoglobin - haemoglobinic acid
Encourages oxygen to dissociate
Explain the role of bicarbonate ions (HC03-) in gas exchange
Produced alongside carbonic acid. 70% of carbon dioxide is carries in this forms
Lungs, bicarbonate ions convert back to carbon dioxide
