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| 7093794838 | Thermoregulatory Centre | -Monitors and controls body temperature. It is in the hypothalamus -Temperature control is the process of keeping the body at a constant temperature of 37°C. -Needs to be at this temperature as this is where enzymes work best How is body temp monitored and controlled: -Receptors in the TRC are sensitive to temp of blood flowing through them -blood and skin hair cells receptors sense temperature and send signals to TRC | 0 | |
| 7093794839 | What happens if the body temperature is too high | Impact: The body shuts down; cells denature; enzymes work less efficiently -More energy needs to be transferred to your surroundings: -Receptors sense change in temp - skin or brain receptors -TRC is a co-ordination centre - receives info from receptor cells and triggers the effectors automatically. -Effectors - eg sweat glands, skin -When we are too hot, blood vessels supplying blood to the skin can swell or dilate (vasodilation). This allows more warm blood to flow near the surface of the skin, where the heat can be lost to the air. Lumen widens and blood flows closer to the skin to release heat and sweating occurs. -Sweat glands in skin produce more sweat. Goes onto the skin and cools it down as it evaporates. Less water evaporates on a humid day | 1 | |
| 7093794840 | What happens if the body temperature is too low | -Receptors in brain and skin sense the change -TRC receives signals and triggers effectors -Effectors respond to counter the change Changes: -Hairs stand on end -Vasoconstriction -Shiver - muscles contract which need to then respire (exothermic reaction) which transfers energy to warm the body -Sweat production is reduced | 2 | |
| 7093794841 | How is the water balance maintained? | Level of water in the body needs to be controlled. For your body to work properly things need to be constant -The kidneys maintain our water balance by producing urine of different concentrations. -When the water level of our blood plasma is low, more water is reabsorbed back into the blood and the urine becomes more concentrated. -When the water level of our blood plasma is high, less water is reabsorbed back into the blood and our urine is more dilute. | 3 | |
| 7093794842 | How is Water lost from the body | Water is lost: -Exhalation -Urine -Sweat Mineral Ions: -Sweat -Urine CO2 -Exhalation | 4 | |
| 7093794843 | Waste Products | Produced through chemical reactions in the body. Two main ones - CO2 and Urea | 5 | |
| 7093794844 | CO2 | Produced during respiration. Needs to be removed because it produces an acidic solution - this would effect the working of enzymes Getting CO2 out of the body: -CO2 diffuses out of cells into blood down concentration gradient -It diffuses from blood to the alveoli in the lungs -Excreted from the lungs while breathing out. Water is also breathed out | 6 | |
| 7093794845 | urea | -Nitorogous waste produced by the breaking down of amino acids when you eat too much protein | 7 | |
| 7093794846 | Urine | Urea is a waste product (excess amino acids) made in the Liver. -Urea passes from liver cells into the blood -Filtered out of blood by kidneys -Passed out of the body in urine produced by kidneys The kidneys spurt urine into the ureters which then pass it into the bladder, where it collects ready to be expelled from the body via the urethra. Urea is produced when you eat more protein than you need, to when your tissues are worn out. Deamination - the liver breaking down the excess amino acids, creating ammonia - Waste product is created - urea which is then excreted by the body | 8 | |
| 7093794847 | sugar blood levels | this is controlled to provide cells with a constant supply of energy. The blood sugar level is controlled by the release and storage of glucose, which is in turn controlled by a hormone called insulin. | 9 | |
| 7093794848 | Importance of the Kidneys | Important for excretion and homeostasis. They control water balance and remove excess water and mineral ions. -If you are short of water, the kidneys conserve it. -If you have too much water - they produce urine to get rid of it | 10 | |
| 7093794849 | Substances in Urine | Water, urea, mineral ions | 11 | |
| 7093794850 | What the kidneys do | -The kidneys filter blood. -As the blood passes through the kidneys, all the small molecules are filtered out of the blood. This includes molecules of: water salt glucose mineral ions urea (a waste product from the breakdown of proteins) Selective Reabsorption: This is done via the tubules The kidneys then reabsorbs ALL of the glucose and as much water and salt as the body needs, putting them back into the blood. This leaves some water and salt, and all of the urea, which is now called urine. The urine passes from the kidneys to the bladder, where it is stored prior to being excreted from the body. The kidneys do more than just control the body's water balance. They also control: The level of salts in the blood. The excretion of urea and other metabolic waste. The amount of water reabsorbed is controlled by a very sensitive feedback mechanism | 12 | |
| 7093794851 | How the kidneys are controlled | -ADH is a hormone produced by the pituitary gland that is situated just below the brain. IT controls the amount of water in the body. -A receptor in the brain monitors the concentration of the blood plasma. s ADH into the bloodstream, which travels in the blood to the kidneys. The more concentrated the plasma i.e. less water, the more ADH is released into the blood. When the ADH reaches the kidneys, it causes them to reabsorb more water. This keeps more water in the body and produces more concentrated urine. When the plasma is more dilute, less ADH is released into the bloodstream. This allows more water to leave the kidneys, producing a more dilute urine. This method of control is an example of negative feedback. Receptor: Brain Effector: Kidney | 13 | |
| 7093794852 | Kidney failure | When the kidneys stop working properly. -Since the kidney is responsible for the removal of waste from the blood, any damage (either from accidents or disease) can lead to a build-up of poisonous waste products in the body. We can survive without one kidney very well, but total kidney failure would be fatal if not treated. Treatment can take the form of dialysis on a kidney machine or a kidney transplant. | 14 | |
| 7093794853 | kidney dialysis | -Not a cure, just a treatment. Helps stop toxins such as urea and mineral ions building up in the blood. -A dialysis machine can keep a patient alive until a transplant becomes available. -The patient's blood is passed through the machine and cleaned of any waste products the kidneys would have otherwise removed. However, dialysis machines have several disadvantages: Dangers: Blood Clots Infections They are expensive. The patient must have his or her blood connected to the machine for several hours each week. Patients must follow a very strict diet to avoid complications. They only work for a limited time for a patient. Dialysis fluid -Contains no urea -Same ions and glucose as a healthy person so there is no net movement | 15 | |
| 7093794854 | Kidney Transplant | The only cure for kidney failure A kidney transplant can save the patient's life, and after a transplant the patient can live a relatively normal life. This is clearly a better option than a machine -A kidney donor can be living as you can live with one kidney -Family members are a good choice as they have similar genes and blood types so less chance of rejection Kidney transplants also have several disadvantages: -Any major surgery carries some risk. -The kidney may be rejected by the body of the patient and so drugs (immuno-suppressant drugs) are used constantly to help prevent rejection. -A precise match of tissue type is needed. About half the donated kidneys come from family members (this is known as a 'living donor'). -There is a severe shortage of donors. Cheaper over time than dialysis. Works for 10 years | 16 | |
| 7093794855 | diagram of kidney dialysis |  | 17 | |
| 7093794856 | advantages and disadvantages of organ transplants | reject the organ expensive works for only 10 years no more dialysis works for 10 years cheaper than 10 years of dialysis | 18 |
