FORM THREE BIOLOGY STUDY NOTES TOPIC 5: REGULATION

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REGULATION

  FORM THREE BIOLOGY STUDY NOTES TOPIC 5: REGULATION

 
Concept of Regulation
The Concept of Regulation
Explain the concept of regulation
Living organisms are subjected to wide variations in temperature, light, acidity, salinity, wind speeds, availability of water minerals and nutrients. These environmental factors create a shifting external setting to which organisms must adjust or die.
The central problem for a living thing is to maintain a steady state internally in the force of an often harsh and fluctuating external environment.
Homeostasis is the maintaining of a constant condition of the internal environment of the body by regulatory process. OR It is the maintenance of constant internal balance despite fluctuation in the external environment.
Regulation is the process of controlling the internal body environment and needs. For the body to function properly things need to be regulated in the body.
Reasons that show importance of regulation
  1. Maintaining favorable condition such as pH and required ionic concentration for the functioning of cells, tissues and organs.
  2. Enabling organisms to get rid of body wastes and useless materials for example excess water and salts
  3. Enabling organisms to get rid of excess materials for example excess water and salts
  4. Ensuring survival of the organisms
Various Types of Regulation
Mention various types of regulation
The following are the types of regulation:
  1. Temperature regulation (thermoregulation)
  2. Blood sugar regulation
  3. Osmoregulation

 

Blood Sugar Regulation in Mammals
The Mechanisms of Regulating Sugar Level in the Blood
Explain the mechanisms of regulating sugar level in t he blood
Blood sugar regulation is the maintenance of a relatively constant blood glucose level of the body. The end product of digestion of carbohydrate is mainly simple sugars or glucose.
Glucose is absorbed from the alimentary canal active transport into the blood stream. Hence the blood sugar level in the blood rises to the extent that regulation of it is necessary.
Blood sugar in mammals is regulated using hormones, which are insulin and Glucagon. These hormones are secreted by a specialized group of pancreatic cells called islets of Langerhans. The alpha cells of the islets of Langerhans secretes Glucagon while the beta cells secretes Insulin.
When the blood sugar level rises in the body insulin is secreted. The insulin accelerates the entry of glucose into the liver and muscles to be converted into Glycogen.
Glycogen is stored for future use in the liver and muscles
Role of Glucagon in Blood Sugar Regulation
Glucagon is secreted in response to a decline in blood sugar level in the blood stream. Glucagon promotes the conversion of Glycogen to glucose and inhibits the oxidation of glucose in the liver.
However if the level of blood glucose is low, glucagon stimulates the conversion of amino acids into glucose. The glucose formed is released into the blood stream.
NOTE:Failure of a pancreas to secrete insulin and glucagon results to a disease called Diabetes Mellitus
The Causes, Symptoms, and Effects of High and Low Sugar Levels in the Blood
Outline the causes, symptoms, and effects of high and low sugar levels in the blood
It’s important to treat symptoms of high blood sugar right away to help prevent complications
Causes
Your blood sugar may rise if you:
  • Skip or forget yourinsulinororal glucose-lowering medicine
  • Eat too many grams of carbohydrates for the amount ofinsulinyou took, or eat too many carbs in general
  • Have an infection
  • Are ill
  • Are under stress
  • Become inactive orexerciseless than usual
  • Take part in strenuousphysical activity, especially when your blood sugar levels are high andinsulinlevels are low
Symptoms
Early signs include:
  • Increased thirst
  • Headaches
  • Trouble concentrating
  • Blurredvision
  • Frequent peeing
  • Fatigue(weak, tired feeling)
  • Weight loss
  • Blood sugar more than 180 mg/dL
Effects
Ongoing high blood sugar may cause:
  • Vaginal andskininfections
  • Slow-healing cuts and sores
  • Worsevision
  • Nerve damagecausing painful cold or insensitive feet, loss ofhairon the lower extremities, orerectile dysfunction
  • Stomachand intestinal problems such aschronic constipationordiarrhea
  • Damage to youreyes, blood vessels, orkidneys
Low Blood Sugar
Symptoms
Symptoms of low blood sugar can occur suddenly. They include:
  • blurry vision
  • rapid heartbeat
  • sudden mood changes
  • sudden nervousness
  • unexplained fatigue
  • pale skin
  • headache
  • hunger
  • shaking
  • sweating
  • difficulty sleeping
  • skin tingling
  • trouble thinking clearly or concentrating
  • loss of consciousness
If you have hypoglycemic unawareness, a condition in which you do not know your blood sugar level is dropping, your blood sugar can drop so quickly you may not even have warning symptoms. When this occurs, you can faint, experience a seizure, or even go into a coma.
Very low blood sugar is a medical emergency. If you know that someone is diabetic and he or she is experiencing these symptoms, help him or her to eat 15 grams of quickly digesting carbohydrate, such as:
  • a half cup of juice or regular soda
  • 1 tablespoon of honey
  • 4 or 5 saltine crackers
  • 3 or 4 pieces of hard candy or glucose tablets
  • 1 tablespoon of sugar
Causes
Low blood sugar can occur for a number of reasons. It is usually a side effect of diabetes treatment.
Diabetes and Low Blood Sugar:Diabetes affects your body’s ability to use insulin. Think of insulin as the key that unlocks your cells, letting glucose in for energy. People with diabetes use a variety of treatments to help their bodies use the glucose in their blood. One very important treatment is insulin injections.
If you inject too much insulin, your blood sugar may drop too low. People also sometimes inject insulin when planning to eat a big meal, but then they do not eat enough.
Excess physical activity without eating enough can also cause a drop in blood sugar levels.
Other Causes of Low Blood Sugar
You don’t have to have diabetes to experience low blood sugar. Some other causes of low blood sugar include:
  • certain medications, such as quinine
  • drinking too much alcohol
  • some medical conditions, such as hepatitis or kidney disorders
  • a tumor that produces excess insulin
  • endocrine disorders, such as adrenal gland deficiency
Effects
Mildly low blood sugar levels are somewhat common for people with diabetes; however, severely low blood sugar levels can be life-threatening. They may lead to seizures and nervous system damage. Immediate treatment is critical. It is important to learn to recognize your symptoms and treat them fast. For people at risk of low blood sugar, having a glucagon kit, a medication that raises blood sugar levels, is important. Talk to your healthcare provider for more information.

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