Homeostasis Flashcards Preview

Biology > Homeostasis > Flashcards

Flashcards in Homeostasis Deck (23):

What is homeostasis?

The maintaining of a constant internal environment.


What are the functions of the kidneys?

They filter the blood to remove harmful substances such as urea; they then selectively reabsorb the correct amounts of each the substances your body requires.


What do the kidneys produce?

Urine by mixing the waste products after filtering the blood; urea, water and excess ions are the main components of urine.


What is the function of the ureter?

It is a tube which allows urine to move from the kidneys to the bladder where it is stored before being excreted through the urethra.


How does kidney dialysis work?

The patient is linked up to the dialysis machine as it carries out the function of the kidneys; urea, excess glucose and excess ions diffuse out of the dialysis tube through the partially permeable membrane; the dialysis solution contains glucose and ions at the same concentration as the blood so that no diffusion takes place.


What are the advantages / disadvantages of using a kidney dialysis machine?

It allows the patient to lead a relatively full, active life; it is a time consuming process which usually involves a lot of time in hospital; the patient has to keep a very controlled diet.


What are the advantages/ disadvantages of kidney transplants?

The patient is free from restrictions which come with kidney dialysis; there is a high risk of the body rejecting the donor organ; the patient must take immunosuppressants which prevent the body dealing effectively with infectious diseases; there is a shortage of kidney donors.


What is glycogen?

A storage carbohydrate found in the liver and muscles which can release glucose.


What is glucagon?

A hormone which increases the concentration of glucose in the blood as it causes glycogen to be converted into glucose.


What is insulin?

A hormone that reduces the concentration of glucose in the blood as it causes excess glucose to convert into glycogen.


How is type 1 diabetes caused?

When you are born with a pancreas which doesn't produce enough insulin to effectively control the concentration of glucose in the blood.


How can type 1 diabetes be treated?

Regular injections of insulin allow glucose to be kept relatively controlled; regular mealtimes and smaller amounts of carbohydrate consumed reduce the sudden peaks in blood glucose.


What can type 2 diabetes be a result of?

Obesity or lack of exercise.


How can type 2 diabetes be treated?

Eating a balanced diet; losing weight and doing regular exercise; taking drugs to make insulin more effective in the body.


How is the core body temperature controlled?

The thermoregulatory centre in the brain contains receptors which monitor the temperature of the blood flowing through the brain.


What is the danger if your core body temperature rises too high?

Your enzymes can denature so they are no longer able to catalyse the reactions in the body.


What is vasodilation and why does it occur?

It is the dilation of capillaries near the surface of your skin which allows more blood to flow through them; your skin flushes so that more energy by radiation when your core body temperature rises too high.


What is produced when your core body temperature increases?

More sweat is produced; this cools your body as it uses thermal energy from the skin to evaporate.


What is the danger if your core body temperature falls too low?

The rate of reactions in your body decreases and you don't release enough energy; your cells begin to die.


What is vasoconstriction and why does it occur?

It is the constricting of the capillaries near the surface of the skin which reduces the flow of blood through them; this reduces the energy lost by radiation from your skin if your core body temperature drops too low.


Why does shivering occur?

Shivering occurs if your core body temperature falls low; your muscles contract and relax rapidly and this movement requires lots of energy from respiration; this is an exothermic reaction so energy is lost to the surroundings as heat and you warm up.


Where is urea produced?



How are excess ions removed from the body?

In urine and through sweat.