B3.3 (Homeostasis) Flashcards
What is the job of the pancreas?
The pancreas moniters and controls the concentration of glucose in the bloodstream and releases insulin into the blood stream when the glucose levels are TOO HIgh
Why is it important to moniter the levels of glucose?
Glucose is an important part of respiration to produce energy and also can change the rate of osmosis if it is not at the right amount in the bloodstream
What is the name of glucose when it is stored in the liver or muscle cells?
Glycogen
What is type 1 diabetes?
Type 1 diabetes occurs when the pancreas is unable to produce enough insulin to bring glucose levels down when they are too high
How can you control type 1 diabetes?
- Self conducting blood tests and injecting with glucose
- Moniterring diet to not eat foods that will cause quick increases in blood glucose
- Doing exercise to increase respiration and lower blood glucose
What are the advantages and disadvantages of self injecting with insulin at multiple points throughout the day?
+ Cheaper
+ More discrete
- Uses more insulin
- Requires more careful control over diet and exercise
- Often does not control levels as well
What are the advantages and disadvantages of wearing a blood glucose pump?
+ Allows more precise amounts of insulin to better maintain blood glucose levels
+ Uses less insulin and moniters how much you use
+ Reduces risk of long term side effects
- More expensive
- Uncomfortable to wear
- Scar tissue around injection sites
What is glucagon?
Glucagon is a hormone secreted by the pancreas that causes the liver to turn stored glucose (glycogen) back into the blood stream as glucose and increase the blood glucose level
What are examples of waste products removed by the body?
Carbon dioxide and Urea
Removed as they could interfere with chemical reactions in the body or damage cells
Why is carbon dioxide produced and how is it removed?
Carbon dioxide is a waste product of respiration and is removed through exhalation
Why is Urea produced and how is it removed?
Urea is produced in the breakdown of amino acids in the liver and is removed through the kidneys to make urine
What organ is responcible for maintaining the amount of water we take in and the amount of water we lose through breathing, sweating, and excretion?
The kidneys
How do the kidneys maintain homeostasis within the moisture levels of the body?
When water levels in blood plasma is low, more water is reabsorbed back into the blood stream by the kidneys. This causes the urine to be very concentrated
When the water in the blood plasma is high, less water is reabsorbed into the blood stream causing the concentration of the urine to be dilute
What factors affect the levels of blood water in the body?
- External temperature, as you lose heat when you sweat
- Exercise, as exercise causes you to sweat
- Fluid intake that dilutes blood plasma
- Salt intake
When is blood plasma at its most concentrated?
When it has lost the most water
What are the tiny filtering units in the kidneys called?
Nephrons
How do the nephrons clean the blood?
By removing urea and excess minerals
What is the first stage of cleaning the blood?
Filtration
Blood passes through the capillary and small molecules such as urea, water, and ions are filtered into the nephron whereas the larger molecules continue in the blood stream
What is the second stage of cleaning the blood?
Selective reabsorbtion
Not all the small molecules filtered out are harmful and so the kidney must reabsorb some into the blood through active transport by osmosis.
These molecules include glucose, water, ions
The nephron have a large surface area and mitochondria to maximise active transport rate
What is the third and final stage of cleaning the blood?
Urine
The waste molecules that are not reabsorbed continue in the nephron tubule and are passed down to the bladder to be excreted
What is kidney failure?
Where the kidney cannot efficiently moniter and clean the blood causing fatal amounts of urea and co2 to build up in the blood stream
How can dialysis to be used to treat kidney failure?
- High urea levelled blood is removed from the patient and mixed with blood thinners to prevent clotting
- In the machine, the blood and dialysis fluid are separeated with a partially permeable membrane and run against eachother
- This dialysis fluid causes a concentration gradient allowing an exchnage of urea to the dialysis fluid and the blood is clean! it is returned to the body ody ody
Why does dialysis fluid contain a similar level of glucose and ions to that in normal blood plasma?
This means a concentration gradient will not occur and so glucose or ions will not be accidently removed or added to the patient
However, if the patient is too low or high in either, a concentration gradient will form and the dialysis will be able to replenish them!
Why is there no urea in the dialysis fluid?
To maximise the concentration gradient and cause the urea in the blood stream to quickly diffuse into the dialysis fluid
How can dialysis negatively affect a persons lifestyle?
- Patient must be connected 2-3 times a week for 4-6 hours
- When not connected they must moniter their diet carefully and avoid high salt foods and high protein foods
What precautions can doctors take to avoid organ rejection?
- Make sure the patient and the donor have similarly formed antigens, however this can lead to long waits
- The patient can take immuno-suppressant drugs for the rest of their life which suppresses the immune system (making them more succeptible to infeciton)
What are the advantages and disadvantages of donor kidneys?
+ Process is cheaper for NHS
+ Patient can lead a normal, worry free life
- Must take immuno suppressant drugs
- Kidney only lasts 8-9 years
- Long wait / shortage of organ donors
What are the advantages and disadvantages of kidney dialysis?
+ Available and accessible to all patients
+ No need for drugs
- Expensive
- Impacts greatly on lifestyle of patient
- Patient must limit their diet in between sessions
What is the optimum constant core temperature?
37 degrees c
How does a body react when it is too cold?
- Capillaries and blood vessels constrict, minimising heatloss from skin (VASOCONSTRICTION)
- Shivering causes muscle movements meaning they respire and release energy that warms the body
How does the body react when it is too hot?
- Capillaries and blood vessels dilate maximising heatloss by radiation (VASODILATION)
- Body sweats, increasing heat loss due to the heat energy it takes to evaporate water
What part of the brain dictates the bodies responce to temperature change?
The thermoregulatory centre
How can hair keep us cool or warm?
When we are cold, hairs stand up and trap a layer of air around the skin as an extra layer of insulation
