Topic 5 Transport in Humans Flashcards
What is mass transport?
• movement of relatively large quantities of molecules at high speeds via transport system eg circulatory system
What are the percentages of components of blood?
Plasma = 55%
White blood cells/platelets = less than 1%
Red blood cells = 45%
What is the structure of plasma?
- mostly water
- some proteins + hormones
What is the function of the plasma?
Transports:
- carbon dioxide
- digested food molecules
- urea
- hormones
- heat energy
Describe the structure and function of red blood cells
- Carry oxygen round body in form oxyhaemoglobin
- Oxygen binds to haemoglobin protein inside red blood cell
- Biconcave shape (increase sa)
- No nucleus (more room for haemoglobin)
Practical: investigate the evolution of carbon dioxide from maggots
- Suspend maggots inside test tube on mesh
2. Hydrogen carbonate indicator underneath, will go orange as maggots are respiring aerobically -> co2 produced
Practical: investigate the evolution of heat from respiring seeds
- Use two vacuum flasks: one containing living germinating seeds + other containing boiled seeds
- Insert thermometer with cotton wool bung to prevent it falling out, to measure temp
- Measure initial temperature
- Leave seeds for a few days + measure end temperature
What would the result be of the germinating seed practical?
- Germinating seeds would release heat energy since they are respiring so temp would increase
- boiled seeds enzymes have denatured, + enzymes required for respiration, so no heat energy released so temp stays same
Describe the method for the yeast practical
- Measure fixed vol of glucose solution + add to boiling tube
- Place in water bath for 5 mins to acclimatise
- Weigh fixed mass of yeast + add to boiling tube
- Use pipette to oil to cover top of solution to prevent oxygen from entering (prevent aerobic respiration)
- Use delivery tube + bung to connect boiling tube to another test tube half filled w lime water
- Start stop clock and count no of bubbles produced in one min
- Repeat + take a mean at each water bath temp
What are the control variables in the yeast experiment?
- mass of yeast
- volume and concentration of sugar solution
- time for timing
What are sources of error in yeast experiment?
- bubbles may form too quickly to be counted accurately
- diff vol of co2 released depending on size of bubble
What are the results of yeast experiment?
0 degrees enzymes still work but very slowly, so rate of respiration = low
40 degrees optimum temp
80 degrees denatured = so rate of respiration very low
Describe structure and function of two main white blood cell types
- Phagocyte
- > multi lobed nucleus
- > engulfs bacteria and digests them w/ enzymes - Lymphocytes
- > large nucleus + halo of cytoplasm
- > release antibodies that bind to antigens on surface of pathogens and mark them for engulfing by phagocyte
Describe the process of a primary immune response in an animal
Primary immune response
1. Pathogens present
- Lymphocytes produce antibodies that are complementary to antigens on pathogen
- These attach to surface of pathogen, marking it out for phagocytes to engulf + destroy
- Some of the lymphocytes become memory cells + remain in the blood
How do vaccines work?
- Dead pathogen injected
- (Primary immune response) lymphocytes produce antibodies complementary to antigens on surface of pathogens
- Some of the lymphocytes will become memory cells + remain in the blood
- (Secondary immune response) If the pathogen is met, it is recognised by the memory cells which produce larger quantities of antibodies faster
- These attach to the surface of the pathogens, targeting it for destruction by phagocytes
What are platelets?
- fragments of cells
- produced in bone marrow
- no nucleus
How do platelets work?
- If skin = cut, exposure to air stimulates platelets to produce a chemical
- This causes soluble plasma protein fibrinogen to change into insoluble fibres of fibrin, forming a net across wound.
- Blood cells get trapped in this net forming a clot
- Prevents further loss of blood and entry of pathogens
- Clot develops into scab which protects damaged tissue while new skin grows
What is the structure of the heart?
- Muscular walls to provide strong heartbeat
- Muscular wall of left ventricle = thicker -> blood needs to be pumped all around body rather than just to lung like right right ventricle
- 4 chambers to separate oxygenated from deoxygenated blood
- Valves to prevent blood back flow
- Coronary arteries that supply heart with oxygenated blood
Describe the cardiac cycle
- Atria contract-> atrial pressure > ventricle pressure - atrioventricular valves open + blood moves into ventricles
- ventricles contract -> ventricular pressure > arterial pressure - semi lunar valves open + blood enters arteries (av valves shut)
- Ventricles relax - semi lunar valves shut as arterial pressure > ventricle pressure
Explain how the heart rate changes during exercise and under the influence of adrenaline
- Muscles require more energy - respiring at higher rate -> heart rate will increase -> pump more oxygen and nutrients round body and remove waster products
- Stroke volume will also increase - heart will pump more each time
- Adrenaline = hormone released from adrenal glands
- > makes heart beat faster + harder
What are causes of CHD?
- high blood pressure
- poor diet
- smoking
- stress
- lack of exercise
Why is a diet rich in fat bad and what does this go on to cause?
- increases cholesterol levels
1. Cholesterol + other fatty substances deposited in coronary arteries (atherosclerosis)
2. Causes blockage, preventing RBCs from passing through
3. RBCs stick together and form clot
4. Prevents oxygen + glucose from reaching cardiac muscle cells
5. Stops aerobic respiration + muscle cells start respiring anaerobically
6. Build up of lactic acid + muscle can no longer contract
7. Eventually muscle cells will die + person has a heart attack
What is the structure + function of an artery?
- Carry OXYGENATED blood AWAY FROM HEART (except pulmonary artery, which is deoxygenated)
- Thick wall w muscle fibres + elastic tissue (able to stretch + recoil and withstand high pressure)
- Small lumen -> maintain high pressure
What is the structure + function of a vein?
- carry DEOXYGENATED blood towards heart
- Large lumen -> blood low pressure
- Thin muscular walls w/ elastic tissue
- Valves to prevent back flow of blood
