85000
Description
Flashcards by Gemma Bradford, updated more than 1 year ago
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Created by Gemma Bradford
almost 11 years ago
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| Question | Answer |
| Explain the features on one heartbeat on an ecg | P wave - contraction of atria QRS complex - contraction of ventricles T wave - relaxation of ventricles |
| How do you calculate heart rate | Heart rate (bpm) = 60/ time taken for one heartbeat (s) |
| What is the normal range at rest for an adult heart rate | 60-100 bpm |
| What is fibrillation | An irregular heartbeat that can result in fainting |
| Describe an artery | Carry blood from heart to rest of body, thick muscular walls with elastic tissue, endothelium is folded, small lumen |
| Describe a capillary | Branched from arteries, connecting to veins, exchanges substances between itself and other cells, one cell thick endothelium, large lumen |
| Describe a vein | Take blood back to the heart, thin muscular wall with little elastic tissue large lumen, contain valves |
| What is tissue fluid | Fluid surrounding cells in tissues, made from substances that leave the blood |
| What is the difference between a source and a sink | Source = where assimilates are produced Sink = Where assimilates are used up |
| What is a capillary bed | Network of capillaries in an area of tissue, where substances move out of capillaries into tissue fluid by pressure filtration |
| What is translocation | Movement of assimilates from source to sink |
| Give an example of translocation | Source for sucrose is leaves, sinks are food storage organs/meristems |
| How do enzymes maintain a concentration gradient from source to sink | By changing dissolved substances at the sink into something else/breaking them down to lower concentration at sink |
| What are assimilates | Substances that become incorporated into the plant tissue - sugars |
| Describe the start of a capilalry bed | Nearest to arteries, high hydrostatic pressure forcing fluid out of capilalries and into space around cells = forming tissue fluid |
| What is transpiration | Evaporation of water from a plant's surface as a result of gas exchange for photosynthesis |
| How does light affect transpiration rate | Stomata open more in more light = allowing for more water to evaporate out |
| Describe the end of a capillary bed | Water potential is lower than in tissue fluid, so some water re-enters by osmosis, low hydrostatic pressure |
| How does temperature affect transpiration rate | Warmer water molecules have more energy, so they evaporate from cells inside leaf faster = increasing water potential gradient between inside and outside of leaf |
| How does humidity affect transpiration rate | If air around stomata is dry, water potential gradient between leaf and air is increased |
| Give a difference between blood and tissue fluid | Tissue fluid does not contain any red blood cells or big proteins, as they are too large to be pushed out of capillary walls |
| How does wind affect transpiration rate | Air movement blows away water molecules from around the stomata, increasing water potential gradient |
| Name 4 precautions to take when setting up a potometer | 1. Cut shoot underwater and at a slant 2. Assemble potometer and insert shoot underwater 3. Dry leaves 4. Allow time for shoot to acclimatise before shutting tap |
| Name 4 adaptations of xerophytic plants | 1. Stomata sunk in pits 2. Curled leaves 3. Layer of hairs on epidermis 4. Less stomata |
| What does a potometer test | Estimates transpiration rate by water uptake of the plant, can test effect of different factors on rate |
| What is the lymphatic system | Where the tissue fluid did not re-enter at end of capillary bed, so instead enters lymph vessel = becoming lymph |
| Why does rate of transpiration fluctuate at different times of the day | Because factors are not constant |
| How does water enter a plant | Soil - root hair cells - root cortex including endodermis - xylem Osmosis |
| Describe haemoglobin | Found in red blood cells, carries oxygen around the body, can carry 4 oxygen molecules, large protein with quaternary structure, made of four polypeptide chains each with it's own haem group |
| Does soil have a high water potential or low | High, so it diffuses into the root hair cells |
| Do leaves had a high or low water potential | Low |
| Describe the symplast pathway | Travels through cytoplasm of cells and through plasmodesmatas to reach xylem vessel |
| Describe the apoplast pathway | Goes through cell walls, blocked by casparian strip where it takes the symplast pathway to reach the xylem vessels |
| Outline the association and disassociation of oxygen | Lungs = oxygen joins to iron in hb to form oxyhb Body cells = oxygen leaves oxyhb and turns back into hb |
| What is a transpiration stream | Movement of water from roots to leaves |
| What is association of oxygen | Loading of oxygen onto hb |
| What is cohesion | Where water molecules are attracted to eachother, so the whole column of water moves up the xylem |
| What is tension | As water evaporates from leaves, this creates a suction pulling more water into leaf |
| What is disassociation | Unloading of oxygen from oxyhb |
| What is adhesion | Where water molecules are attracted to the xylem vessel walls, helping water to rise up through vessels |
| What is affinity for oxygen | Tendency a molecule has to bind with oxygen |
| What is the casparian strip | Waxy, waterproof strip in cell walls at endodermis |
| What are mesophyll cells | Type of leaf cell |
| What is the affect of air bubbles in the xylem | They can block the column of water, preventing water from reaching the cells |
| What is partial pressure of oxygen pO2 | Measure of oxygen concentration, the higher the concentration of dissolved oxygen in cells = higher partial pressure |
| Why do plants need transport systems | Need water, minerals and sugars to live, and need to get rid of waste substances. Multicellular with small SA:V ratio. If they exchanged substances directly, it would be too slow |
| How does pO2 affect haemoglobin's affinity for oxygen | Oxygen loads onto hb in a high pO2, oxygen unloads in a low pO2 |
| What is lignin | Spiralled woody substance in xylem vessels, supporting the xylem walls and allowing flexibility to prevent stem from breaking |
| Where is there a high pO2 | Alveoli in lungs |
| What are pits in the xylem vessel | In walls where there is no lignin, allowing water and mineral ions to move in/out of vessels to supply other types of cells with water |
| Where is there a low pO2 | Respiring tissue |
| What is the purpose of having no end walls in xylem vessels | Making an uninterrupted tube allowing water to pass up through centre easily |
| What does an oxygen dissociation curve show | How saturated hb is with oxygen at a given pO2 |
| What are xylem vessels formed of | Long tube like structures formed from vessel elements, dead cells containing no cytoplasm |
| What are dictoyledonous plants | Green, non-woody plants bushes and trees |
| How is phloem formed | From cells arranged in tubes, living cells |
| Why are disassociation curves S shaped instead of a straight line | When oxygen first binds with hb, it alters it's shape to make it easier for other oxygen molecules to bind. As hb becomes more saturated with oxygen, it's shape makes it harder for other oxygen molecules to join. Steep part of curve is where it's easy for oxygen molecules to join |
| What living cells are in the phloem | Phloem fibres, parenchyma, sieve tube elements and companion cells |
| Describe sieve tube elements | Joined end to end to form sieve tubes, sieve plates have holes to allow sugars to pass through, no nucleus, few organelles, thing cytoplasm |
| Describe companion cells | For every sieve tube element, carry out living functions for themselves and sieve tubes such as providing energy for active transport of sugars |
| Why does fetal haemoglobin have a higher affinity for oxygen than adult haemoglobin | Fetus' gets oxygen from mother's blood across placenta, by the time it reaches placenta, oxygen saturation has decreased as it has been used up by the mother's body. Placenta has a low pO2, helping oxygen to unload. Curve is to the LEFT of adult hb curve. |
| Are the sugars transported in the phloem whole or dissolved | Dissolved |
| What is a single circulatory system | Blood only passes through the heart once for each complete circuit of the body |
| What is a double circulatory system | Blood passes through the heart twice for each complete circuit around the body |
| What is the partial pressure of carbon dioxide pCO2 | Measure of the concentration of CO2 in a cell |
| What is a closed circulatory system and give an example | Blood is enclosed in blood vessels - fish |
| How does pCO2 affect disassociation of oxygen from oxyhb | Hb gives up oxygen more readily in a higher pCO2 |
| What is an open circulatory system and give an example | Blood flows freely in body cavity - insects |
| Name features of the right side of the heart | Inferior and superior vena cava, pulmonary artery, right ventricle, right atrium, semi lunar valve, tricuspid valve |
| Name features of the left side of the heart | Aorta, pulmonary vein, left atrium, left ventricle, semi lunar valve, bicuspid valve |
| Outline the bohr effect | CO2 in red blood cells converted to carbonic acid by carbonic anahydrase, carbonic acid splits into hydrogen and hydrogencarbonate ions, the increase in hydrogen ions causes oxyhb to unload oxygen so hb can take up hydrogen ions forming haemoglobonic acid |
| What is the purpose of heart valves | Prevent backflow of blood |
| Why is the heart muscle thicker on the left | As left ventricle pumps blood around the whole body |
| What is the main advantage of the bohr effect | To get more oxygen to respiring tissues |
| What is the word equation for aerobic respiration | glucose + oxygen ¬ carbon dioxide + water + energy |
| What is the purpose of coronary arteries | To supply the heart with an oxygenated blood supply |
| What is hydrostatic pressure | Where blood is under high pressure in arteries due to contraction of ventricle walls |
| Give the brief sequence of the cardiac cycle | 1. Ventricles relax, atria contract 2. Ventricles contract, atria relax 3. Ventricles relax, atria relax |
| What is the SAN | Sino atrial node in wall of right atrium, sending waves of electrical activity over the atrial walls |
| What is the purpose of non-conducting collagen tissue in the heart | Prevents the waves of electrical activity from being passed directly from artia - ventricles. Causes delay which allows for the atria to empty before ventricles contract |
| What is the AVN | Atrioventriclular node passing waves of electrical activity on to the bundle of HIS |
| What is the bundle of HIS | Group of muscle fibres conducting waves to purkyne tissue |
| What is the purkyne tissue | Carries waves of electrical activity in walls of ventricles, causing them to contract together from apex upwards |
| What is an elecctrocardiograph | Machine recording electrical activity of the heart |
| What is an electrocardiogram | Trace produced by an electrocardiograph |
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