Homeostasis Flashcards
What is homeostasis?
The maintenance of a constant internal environment
it covers all the functions in the body that do this
What are the six things in the body that need controlled?
The body temperature, Water content, and The ion content of the body mustn’t get too high or too low, or too much water could move in or out of cells damaging them
The blood sugar level needs to stay within certain limits
CO2, a product of respiration, is toxic in high quantities, and has to leave the body via the lungs
Urea, waste product form excess amino acids
Why does body temperature need to be carefully controlled?
Because the enzymes work best at a certain temperature of 37C. If the body gets to hot or cold they won’t work properly and important reactions will be disrupted, this could lead to death
What temperature is the body kept at?
37C
What acts as your personal thermostat?
What does it contain?
What does it recieve?
The thermoregulatory center in the brain
Receptors that are sensitive to the temperature of the blood flowing through the brain
Impulses from the skin, giving the center information about the skin temperature
How does your body keep you cool? (3)
Hairs lie flat
Sweat is produced by sweat glands and evaporates from the skin, which removes heat
The blood vessels supplying the skin dilate so more blood flows closer to the surface. This makes it easier for heat to be transferred from the blood to the environment through radiation
How does your body warm up? (3)
Hairs stand up trapping an insulating layer of air, (no sweat is produced)
Blood vessels supplying the skin capillaries constrict to close off the skin’s blood supply
You shiver, muscles contract automatically, but this requires respiration releasing energy to keep the body warm
What do kidneys do?
What are their three roles?
They clean the blood by filtering it
Removal of urea from the blood
Adjustment of ions in the blood
Adjustment of water content in the blood
Removal of urea What happens to the proteins you don't need? Where does this occur? What is urea produced from? Why is urea dangerous? How do the kidneys sort it out?
As they can’t be stored by the body they are converted into fats and carbs, that can be stored
In the liver
It is a waste product of these reactions
It’s poisonous
It is released form the liver into the bloodstream and filtered out by the kidneys, temporarily stored by the bladder in urine then excreted.
Adjustment of ion content How do ions get into the blood? What happens when the ion content is wrong? balance, cells, damage What happens to the excess ions? But:
They are taken into the body through food and then absorbed (sodium)
There is an upset balance between the water and ions, meaning too much or too little water is drawn into cells by osmosis. Having the wrong amount of water can damage the cells meaning they don’t work as well as normal.
Excess is removed by the kidneys, or lost in sweat
Balance is always maintained by the kidneys
What does urine contain? Why?
Urea, water and ions, to keep the balance in the body
Adjustment of water content
How is water taken in? How is it lost?
What does the body always have to do?
What is water balanced between?
On a cold day if you don’t sweat, you produce… which will be pale and dilute
On a hot day if you sweat a lot, you produce… which will be …… and …..
The water lost when it is hot has to be ….. with water from ….. and ….. to restore the …..
Food and drink, Urine Sweat and the Air we breathe out
Balance the water coming in with what’s going out
Liquids consumed, amount sweated out and amount excreted by the kidneys in the urine.
More urine
Less urine, dark coloured and concentrated
Replaced, food and drink, balance
What do sports drinks replace?
Lost water sugar and ions
What do sports drinks do?
How are these bits used during exercise?
What do some drinks do and how should you be careful about this information?
Help your body keep water, sugar and ions balanced, by replacing them
Water and ions are lost through sweat
Sugar is used by the muscles for respiration
Rehydrate you faster than water or improve your endurance, make sure the info is from a reputable journal and well respected scientists or organisations.
