2 (h) Transport Flashcards
Understand the need for a transport system in multicellular organisms
- they have a small surface area to volume ratio meaning that they have an inefficient rate of diffusion
describe the composition of the blood + their functions
- plasma = liquid that carries dissolved substances
- red blood cells = carry oxygen in haemoglobin
- white blood cells = help defend body against pathogens; theres 2 types (lymphocytes & phagocytes)
- platelets = form blood clots
what does the plasma transport?
- urea = from liver to kidney for excretion
- carbon dioxide = transported to the lungs for exhalation
- digested food = transported to respiring cells
- hormones
- heat energy = to maintain optimum body temperature for enzyme activity for metabolic reactions
what are the adaptations of the red blood cells that makes them suitable to transport oxygen
- biconcave shape = to increase the surface to volume ratio for diffusion of oxygen
- no nucleus = to allow more space for haemoglobin to transport oxygen
- thin cell membrane (one cell thick) =
- small and flexible = to fit through narrow blood vessels for efficient transport
- haemoglobin = that combines with oxygen to form oxyhaemoglobin to transport oxygen to respiring cells
describe the structure of the heart and how it functions
PROCESS:
1. Deoxygenated blood from respiring cells are carried by the Vena Cava to the Right Atrium
2. Right Atrium will contract to increase pressure, pushing blood into Right Ventricle through Atrioventricular Valve
3. Atrioventricular Valve closes to prevent backflow of blood from Ventricle to Atrium
4. Right Ventricle will contract to increase pressure, causing blood to be carried out via Pulmonary Artery to be Oxygenated at the Lungs through the Semilunar Valve
5. Semilunar Valve closes to prevent backflow of blood from Artery to Ventricle
6. Pulmonary Vein carries Oxygenated blood from Lungs to the Left Atrium
7. Left Atrium will contract to increase pressure, pushing blood into Left Ventricle through Atrioventricular Valve
8. Atrioventricular Valve closes to prevent backflow of blood from Ventricle to Atrium
9. Left Ventricle will contract to increase pressure, causing Oxygenated blood to be carried out via Aorta to respiring cells around the body
understand how the immune system responds to disease
2 types of white blood cells:
phagocytes = engulf the pathogen and secrete digestive enzymes to remove them from the body. they also have a sensitive cell membrane to detect the pathogen. they have an irregularly shaped nucleus to allow them to fit through narrow passages
lymphocytes = produce antibodies to deactivate the antigens from the pathogen; they have a large nucleus with a lot of DNA to produce a lot of antibodies. they produce memory cells
explain how the heart rate changes during exercise
HEART RATE DURING EXERCICE:
1. During exercise, more energy is needed via respiration to allow muscle contractions to occur to facilitate movement
2. Hence, heart rate will increase to allow more Oxygen transport in blood to respiring cells for movement to occur
3. If energy demand exceeds Oxygen intake, energy may be produced via anaerobic respiration, producing Lactic acid as a waste product
After exercise, heart rate continues to increase as extra Oxygen is needed to break down the Lactic acid produced - Oxygen debt
understand how factors may increase the risk of developing coronary heart disease
CORONARY HEART DISEASE: Blockage of Coronary Artery by Fat globules (forming plaques), causing insufficient Oxygen transport in blood leading to increased anaerobic respiration (due to lack of Oxygen)
* Increase in anaerobic respiration causes build-up of Lactic acid which creates acidic environment for enzymes to denature, hence causing strokes
FACTOR EXPLANATION
POOR DIET = Diets rich in Saturated Fats, Salts and Alcohol increases the presence of Cholesterol in diet, increasing the risk of Coronary Heart Disease (CHD)
STRESS = Stress stimulates the secretion of Hormones that increases blood pressure, therefore increasing the risk of the buildup of Fatty plaques to cause Coronary Heart Disease (CHD)
SMOKING = Nicotine in cigarettes causes vasoconstriction - the narrowing of blood vessels, increasing the risk of the buildup of Fatty plaques to cause Coronary Heart Disease (CHD)
understand how the structure of arteries, veins and capillaries relate to their function
ARTERIES
- Transports Oxygenated blood away from the Heart (excluding Pulmonary Artery)
- Thick muscular walls to withstand high pressure
Narrow lumen to maintain high pressure to pump blood around the body
VEINS
- Transports Deoxygenated blood towards the Heart (excluding the Pulmonary Vein)
- Thin walls to allow Skeletal muscle to exert pressure on Vein
- Wide lumen to transport large volume of blood
Valves to prevent the backflow of blood under low pressure
CAPILLARIES
- Facilitates material exchange between cells - e.g., gas exchange
- Thin walls (one cell thick) that are porous and permeable for efficient material exchange via diffusion
- Narrow lumen to fit between cells for extensive branching, which increases surface area to volume ratio for efficient material exchange via diffusion
understand the general structure of the circulatory system
EFFECT OF ADRENALINE ON HEART RATE
- During times of fear or stress, Adrenaline is produced by Adrenal glands and secreted into the bloodstream
- As a result, Liver cells convert Glycogen into Glucose to increase blood glucose levels
- Additionally, breathing and heart rate increases to increase blood flow
Hence, the increase in breathing and heart rate allows more Glucose and Oxygen to be transported in the bloodstream to respiring cells for ‘fight or flight’ response to occur
