Topic 6: Homeostasis Flashcards
What is homeostasis?
The regulation of conditions inside the body to maintain a stable internal environment, in response to both internal and external conditions.
What are hormones?
Chemical messengers that are made in certain organs and travel around in the bloodstream, affecting various parts of the body.
What are the 3 main conditions controlled by hormones in the body?
Temperature
Water content
Glucose concentration
Why does temperature need to be kept at optimum level?
Must be kept stable for enzymes to work.
Why does water content need to be kept at optimum level?
Dehydration may make body fluids too concentrated and damage the body, being too hydrated can dilute the body fluids.
Why does glucose concentration need to be kept at optimum level?
Glucose is essential for energy but too high or too low glucose levels can damage the body.
What are hormones carried by?
Blood.
What is the speed of hormone transmission?
Slow.
What is the nervous system carried by?
Neurones.
What is the speed of the nervous system transmission?
Fast.
what are blood glucose levels reduced by?
The hormone insulin (a protein) which is released by the pancreas.
If you have low glucose levels, what effect does insulin have one the pancreas?
Insulin won’t be secreted into the blood.
If you have high glucose levels, what effect does insulin have one the pancreas?
Insulin will be secreted into the blood.
If you have low glucose levels, what effect does insulin have one the liver?
The liver won’t convert glucose into insoluble glycogen.
If you have high glucose levels, what effect does insulin have on the liver?
The liver will convert glucose into glycogen for storage.
If you have low glucose levels, what effect does insulin have on blood glucose levels?
Increases it.
If you have high glucose levels, what effect does insulin have on blood glucose levels?
Decreases it.
What is negative feedback?
A mechanism that lowers raised levels of something, and raises reduced levels of something.
What is an animal which is ectotherm?
An animal that is dependent on external sources of body heat (cold-blooded).
What is an animal which is endotherm?
An animal that is dependent on or capable of the internal generation of heat (warm-blooded).
What is the stimulus in negative feedback of glucose control?
The blood glucose levels rising or dropping.
What is the receptor in negative feedback of glucose control?
The pancreas.
What is the processor in negative feedback of glucose control?
The pancreas.
What is the effector in negative feedback of glucose control?
The liver.
What is the response in negative feedback of glucose control?
If levels are high, the liver the stimulates glucose uptake by cells.
If levels are low, the liver turns glycogen into glucose.
What is type 1 diabetes caused by?
Genetics - a lack of insulin.
What is type 2 diabetes caused by?
Obesity - high glucose in diet and the body no longer responds properly to insulin.
Is insulin produced with type 1 diabetes?
Basically none is produced.
Is insulin produced with type 2 diabetes?
Yes but it’s ineffective.
What is treatment for type 1 diabetes?
Insulin injection.
What is treatment for type 2 diabetes?
Weight loss - dieting exercising.
What does type 1 diabetes usually effect?
Younger ages / at birth.
What does type 2 diabetes usually effect?
Older people, unhealthy people and overweight people.
What happens if you don’t maintain your body’s internal conditions?
Enzymes will denature which slows metabolic reactions.
What are metabolic reaction?
Chemical reactions in organisms.
What is denaturing?
The process of modifying the molecular structure of a protein.
What happens if blood glucose levels are too high?
It effects osmosis.
Insulin is added to the blood to convert excess glucose into glycogen.
What happens if blood glucose levels are too low?
Due to being a form of fuel, low levels can effect respiration negatively.
Glycogen is used as a fuel instead.
How does the body react when we are too cold? (4)
Shivering produces heat
Hair stands up, Goosebumps - traps layer of air
Vasoconstriction
Sweat isn’t produced
How does the body react when we are too hot? (4)
No shivering
sweat produced - heat evaporates it
Vasodilation
Hair lies flat
What is vasodilation?
Blood vessels dilate to allow more blood to enter capillaries.
What is vasoconstriction?
Blood vessels constrict to reduce blood flow in capillaries.
What does a sweat pore do?
Sweat is released onto the skin through the pore, as the sweat evaporates it cools the skin and body.
What does a sweat duct do?
Carries sweat to the surface of the skin.
What does a sweat gland do?
Removes water and salt from the blood, producing sweat.
What do the blood capillaries in the skin do?
The flow of blood through the capillaries can be changed to help control heat loos from the skin.
What does the hair erector muscle do?
Contracts to raise the hair when cold.
Relaxes to lower the hair when hot.
What happens when the hair erector muscles contract?
The hair stands up, trapping a layer of warm air next to the skin to insulate heat in the body.
What happens when the hair erector muscles relax?
Hair lies flat so less air is trapped next to the skin. More heat is lost.
