b3.3-Maintaining Internal Environments Flashcards
b3.3.1-What is normal body temperature?
Your body works best at 37 degrees as this is your optimum temperature for your enzymes. Exposure to extreme cold can reduce core body temperature, exposure to very high temperatures can cause the body to overheat.
b3.3.1-How is body temperature controlled?
The thermoregulatory centre in the brain regulates temperature. It relies on signals received from receptor cells in your skin. When a change in temperature is detected, the brain causes different parts of the body to respond by sending impulses to effectors. These responses return temperature to normal.
b3.3.1-What happens when you get too hot?
Hyperthermia:
-Body hairs lower so hairs on your skin lay flat. This prevents an insulating layer of air being trapped around the body.
-Sweat glands to produce sweat. As the water in sweat evaporates, energy is transferred by heating your body to the environment.
-Vasodilation which is blood vessels supplying capillaries near surface of skin to widen. This increases blood flow through capillaries, increasing heat loss by radiation.
b3.3.1-What happens when you get too cold?
Hypothermia:
-Body hairs rise, trapping layer of air close to skin which insulates body.
-Sweat glands stop producing sweat.
-Vasconstriction which is blood vessels supplying capillaries near surface of skin. This reduces blood flow through capillaries, reducing heat loss.
-Shivering begins as muscles contract and relax quickly. This makes cells respire quicker transferring extra energy by heating.
b3.3.2-Why is it important to control blood sugar levels?
Glucose is an energy store. Chemical reactions transfer energy from glucose to ATP which is used by cells. This allows them to perform normal body functions. It is important that blood sugar levels are kept constant to keep healthy.
b3.3.2-What is insulin?
Insulin is released if high blood sugar levels are detected by the pancreas. Insulin travels in the blood to the liver. It stimulates the liver to turn glucose into glycogen by a series of enzyme-controlled reactions. As there is less glucose in the blood, the blood sugar levels fall.
b3.3.2-What is glucagon?
Glucagon is released by the pancreas if the blood glucose concentration is too low. Glucagon makes the liver change glycogen back into glucose. This is then released into the blood increasing blood sugar levels. Insulin and glucagon act to maintain a constant blood sugar level.
b3.3.2-What is type 1 diabetes?
People with type 1 diabetes can’t produce insulin. The persons immune system has destroyed the pancreatic cells that make insulin. Type 1 diabetes is controlled by insulin injections. They should also exercise regularly and eat a balanced diet.
b3.3.2-What is type 2 diabetes?
People with type 2 diabetes can’t effectively use insulin as the body doesn’t effectively produce it or body cells don’t properly respond to it. Type 2 diabetes is controlled by regulating a persons carbohydrate intake and exercise. It has been linked to obesity so the overweight are encouraged to lose weight. Drugs/injections can also be used.
b3.3.3-Why is it important to maintain water balance?
It is important that water levels in your blood plasma remain constant. Too much water present moves into blood cells causing them to swell and burst. This is lysis. If too little water is present/too much solute, water will diffuse out of your blood cell causing them shrink.
b3.3.3-What is urine and how is it produced?
Urine is a solution made up of water, urea, waste substances. Your kidneys filter out urea as it’s toxic, the urine goes into the bladder. The nephrons of the kidney create urine through ultrafiltration, reabsorption and secretion. Each kidney has around 1 million nephrons.
b3.3.3-How does urine change?
If you’re short of water, your kidneys produce little urine. Water is saved for body’s use. If you have too much water, your kidneys produce lots of urine. Excess water is therefore lost from the body.
b3.3.4-What do your kidneys look like inside?
Capsule-Outer membrane of the kidney. This helps to maintain the kidneys shape and protect it from damage
Cortex-Outer part of kidney
Medulla-Inner part of kidney
b3.3.4-How does the body control how much urine is produced?
Urine amount is controlled through a negative feedback loop. Your hypothalamus detects water potential of your blood as it passes through the brain. It responds by secreting ADH(anti-diuretic hormone) from the pituitary gland. ADH travels in the bloodstream to the kidney where it means more water is reabsorbed into the blood.
b3.3.5-How does the body respond to lack of water?
The body triggers a thirst response in which an impulse is sent to your brain to produce more fluids and kidneys reduce urine. If you do not take on fluids, you will be dehydrated. Symptoms include dark,concentrated urine, headaches and dizziness, lack of energy.
