Homeostasis Flashcards
What is homeostasis?
A self regulating process, by which a living organism can maintain internal stability while adjusting to changes in external conditions.
Why does your body temperature need to be controlled?
To prevent hypothermia, overheating and your cells from denaturing.
Why does your blood PH need to be controlled?
If it is too low or too high your cells will denature.
Why do your blood glucose levels need to be controlled?
To avoid:
- Hyperglycaemia (Your body’s blood glucose
levels are higher than the standard range).
- Hypoglycaemia (Your body’s blood glucose
levels are lower than the standard range).
Why does your water potential need to be controlled?
So you don’t get dehydrated and so your cells don’t swell.
What is a negative feedback loop?
A normal biological response in which the effects of a reaction slow or stop that reaction. It regulates.
What is a positive feedback loop?
This is when the product of a reaction leads to an increase in that reaction. It does not regulate.
What is an example of a positive feedback loop?
During labour a hormone called oxytocin is released, causing stronger contractions. These stronger reactions stimulate the release of more oxytocin. This cycle continues till birth.
What is thermoregulation?
A process which occurs when you are too hot or too cold.
What happens when you are too hot?
- Your blood vessels dilate to release heat.
- Sweat is produced and heat leaves via evaporation.
- Your heart rate increases to circulate blood faster.
What happens when you are too cold?
- You shiver to generate heat.
- Your blood vessels constrict to reduce heat loss.
- Your metabolism increases to produce more heat.
What is vasoconstriction?
When your blood vessels narrow, to reduce blood flow to regulate your temperature.
This reduces heat loss.
What is vasodilation?
When your blood vessels widen, to allow more blood to flow through, increasing blood flow.
This releases heat.
What is an endotherm?
An organism that regulates its body temperature internally.
What is an ectotherm?
An organism that relies on its environment to regulate its body temperature.
How is blood glucose controlled?
- The Islets of Langerhans (Regions in the pancreas with endocrine function).
- Insulin (Helps to use sugar for energy).
- Glucagon (If your blood sugar is low this is released, signalling the liver to release stored glucose).
- Alpha cells (Produce glucagon to increase blood sugar).
- Beta cells (Produce and release insulin).
- Glycogenesis (When glucose is stored in the body as glycogen).
- Glycogenolysis (When glycogen is turned into glucose when a quick source of energy is needed).
- Gluconeogenesis (When new glucose are created from non-carbohydrate sources like amino acids and glycerol).
What are the Islets of Langerhans?
Regions in the pancreas with endocrine function, that contain alpha and beta islet cells.
What does insulin do?
Helps blood sugar enter the body’s cells so it can be used for energy.
What does glucagon do?
If your blood sugar is low this is released, signalling the liver to release stored glucose.
What do alpha cells do?
Produce glucagon to increase blood sugar.
What do beta cells do?
Produce and release insulin.
What is glycogenesis?
When glucose is stored in the body as glycogen.
What is glycogenolysis?
When glycogen is turned into glucose when a quick source of energy is needed.
What is gluconeogenesis?
When new glucose are created from non-carbohydrate sources like amino acids and glycerol.
What does the pancreas do?
- The pancreas detects any changes in the levels of glucose in the blood.
- The Islets or Langerhans are a region in the pancreas that releases insulin and glucagon to regulate the blood glucose levels.
What does the pancreas do if your glucose levels are too high?
- Insulin is released from the beta cells of the islets of langerhans in the pancreas, when high levels of glucose are detected.
- It binds to the insulin receptors of the liver which stimulates the conversion of glucose to glycogen and glucose to fat (glycogenesis).
- This causes the levels of glucose to drop.
How does adrenaline affects your blood glucose levels?
Adrenaline is released by the adrenal glands if your body anticipates danger. This results in more glucose being released from the stores of glycogen in the liver.
How is glucose stored in the body?
- Insulin binds with cell surface receptors on the liver, causing a change in the tertiary structure of the glucose transport protein channels.
- The channels then open and glucose diffuses in.
- This increases the rate of absorption of glucose into the body cells. This is particularly muscle cells and is then used for respiration.
What does the pancreas do if your glucose levels are too low?
- This is detected by the alpha cells of the islets of langerhans in the pancreas. These cells produce glucagon which binds to the receptors of the liver cells.
- This stimulates the conversion of glycogen to glucose (glycogenolysis). Other biological molecules like amino acids and glycerol will also be used to be converted into glucose (gluconeogenesis).
- This causes an increase in blood glucose levels.
What does the hypothalamus do?
Its main function is to keep your body in a stable state called homeostasis. It does its job by directly influencing your autonomic nervous system or by managing hormones
