Thermoregulation + Endocrine system + Control of blood glucose concentration Flashcards
Describe how the brain monitors the temperature of the body
Body temperature is monitored and controlled by the thermoregulatory
centre in the brain
The thermoregulatory centre contains receptors
sensitive to the temperature of the blood.
The skin contains temperature
receptors and sends nervous impulses along sensory neurones to the thermoregulatory centre.
Describe how negative feedback controls body temperature
if body temperature is too high:
temp receptors detect that core body temperature is too high
thermoregulatory centre acts as a coordination centre.
it receives information from the receptors and automatically triggers the effectors
Effectors produces a response to reduce body temperature e.g. shivering)
if body temp is too low:
temp receptors detect that core body temperature is too low
thermoregulatory centre acts as a coordination centre.
it receives information from the receptors and automatically triggers the effectors
Effectors produces a response to raise/increase body temperature e.g. shivering)
What is the body temperature monitored and controlled by
Body temperature is monitored and controlled by the thermoregulatory
centre in the brain
What does the thermoregulatory centre contain
The thermoregulatory centre contains receptors
sensitive to the temperature of the blood.
What does the skin contain to detect temperature
The skin contains temperature
receptors and sends nervous impulses along sensory neurones to the thermoregulatory centre.
Describe how the body responds to restore the normal body temperature if the body temperature is too high
e.g. if a person is exercising
Sweat glands release sweat onto the surface of the skin
The sweat now evaporates and this takes energy from the body to the environment, cooling the body down
_____
The body can also cool itself down by flushing
Under the surface of the skin, there is a fine network of blood capillaries
These capillaries are supplied with blood by blood vessels deeper in the skin
________
If the body gets too hot, the blood vessels supplying the capillaries dilate (they get wider). This is called vasodilation
Because the blood vessels have dilated, this means that more blood flows through the capillaries.
Heat can now transfer out of the blood so the body temperature returns back to its normal level
Describe how the body responds to restore the normal body temperature if the body temperature is too low
The blood vessels supplying the capillaries constrict (they become narrower). This is called vasoconstriction.
Less blood now flows through the capillaries and less heat is lost from the body
Another way we respond when our body temperature drops too low is to shiver
When we shiver, our skeletal muscles contract.
To generate energy for this contraction the muscle cells increase their rate of respiration. This releases heat which warms the body
If our body temperature falls too low then we also stop sweating
Describe why the control of body temperature is a good example of homeostasis
When the body temperature was too high or low - the thermoregulatory centre detected that the body temperature had changed from the normal value.
The body responded to reverse this change and restore the normal body temperature
What is meant by the endocrine system
The endocrine system is composed of glands which secrete chemicals
called hormones directly into the bloodstream.
The blood carries the
hormone to a target organ where it produces an effect
(hormones bind to specific target organs where they trigger an effect)
(each hormone only acts on specific target organs where it produces an effect)
State a key feature of the nervous system
The nervous system is extremely fast (very fast action)
The effect of the nervous system tend to be very short lived (act for a very short time)
Compare the endocrine system and the nervous system
Compared to the
nervous system, the endocrine system tends to produce a much slower effect but the effect is more long lasting (effects act for longer)
endocrine system uses hormones which are chemicals and these are carried in the bloodstream
signals in the nervous system is extremely fast (very fast action)
The effect of the nervous system tend to be very short lived (act for a very short time)
uses electrical impulses which travel down neurones
Glands which make up the endocrine system (state the endocrine glands)
Pancreas - releases hormones which are involved in controlling the concentration of glucose in the blood
Ovaries and testes release hormones involved in puberty and in reproduction
Thyroid gland produces hormones which are involved in growth and in regulating the body’s basal metabolic rate (how rapidly the body’s reactions take place) and temperature
The adrenal glands release the hormone adrenaline which is produced in times of fear or stress
The pituitary gland is located in the brain. This is called a master gland (extremely important)
This gland releases a number of different hormones into the blood depending on the conditions
These
hormones in turn act on other glands to stimulate other hormones to be
released to bring about effects.
(by acting on other glands the pituitary gland can trigger a range of different effects in the body)
Describe the role of the pituitary gland in the endocrine system
The pituitary gland is located in the brain. This is called a master gland (extremely important)
This gland secretes a number of different (several) hormones into the blood in response (depending on) to the conditions
These (pituitary)
hormones in turn act on other glands (and they cause) to stimulate other hormones to be
released to bring about effects.
(by acting on other glands the pituitary hormones can trigger a range of different effects in the body)
Identify the position of different endocrine glands in the human body
(draw a sketch of human body and label positions of different endocrine glands)
https://bam.files.bbci.co.uk/bam/live/content/zmm3kqt/small
why is glucose important that the concentration of glucose in the blood is kept as constant as possible
Needed by every cell to release energy by respiration so it is very important that the concentration of glucose in the blood is kept as constant as possible
What organ monitors and controls the blood glucose concentration
The blood glucose concentration is monitored and controlled by the pancreas
describe the role of the pancreas in terms of blood glucose
The pancreas monitors and controls the concentration of glucose in the blood
What could cause the concentration of glucose in the blood to rise
After a meal rich in carbohydrates, the concentration of glucose in the blood can rise
Describe what happens if the blood glucose concentration is too high
If the concentration of glucose in the blood rises, this is detected by the pancreas. The pancreas produces the hormone insulin
Insulin travels in the bloodstream all around the body and it causes (triggers) body cells to take up glucose from the blood
(…that causes glucose to move from the blood into the
cells.)
Insulin also causes liver and muscle cells to convert excess glucose into glycogen for storage
(Insulin also triggers liver and muscle cells to store excess glucose as a storage molecule called glycogen)
Because glucose is now being taken out of the blood and stored, the concentration of glucose in the blood returns to its normal level. Homeostasis has taken place.
What is diabetes
Condition where the pancreas cannot make enough insulin to control blood sugar or body cells stop responding to insulin made by pancreas
What is it called where in some people, their blood glucose control does not work effectively
Diabetes
How many types of diabetes are there
There are two types of diabetes
What is type 1 diabetes
In type 1 diabetes, the pancreas does not produce enough insulin
How do you know if someone has type 1 diabetes
It is characterised by uncontrolled high blood glucose
levels
Describe and explain this graph
At the start of the experiment, both people ate a meal containing the same amount of carbohydrate - control variable - to ensure results are valid
https://www.youtube.com/watch?v=77oyUdNZ054&list=PL9IouNCPbCxW3lptxS1yHCP2I9YDfM2co&index=9
at 2:37
The concentration of glucose in the blood rises for both people.
In the person without diabetes, the blood glucose concentration rapidly returns to its normal level
That is due to the effect of insulin
However, in the person with type 1 diabetes, the blood glucose concentration rises, and then stays at a high level (only little decrease in blood glucose concentration)
This is because the pancreas cannot produce sufficient insulin
Explain how type 1 diabetes are treated
People with type 1 diabetes monitor their blood glucose concentration and inject themselves with insulin if blood glucose rises too much. e.g. after a carbohydrate-rich meal
normally treated with insulin injections.
https://www.youtube.com/watch?v=77oyUdNZ054&list=PL9IouNCPbCxW3lptxS1yHCP2I9YDfM2co&index=10
at 2:51
State what has happened, at the point of the green arrow
At this point the person with type 1 diabetes has injected themself with insulin
When the person with type 1 diabetes injects themself with insulin, their blood glucose concentration falls
What is type 2 diabetes
In type 2 diabetes, the body cells stop responding to insulin produced by the pancreas
Similarities between type 1 and type 2 diabetes
In people with these conditions their blood glucose control does not work effectively
Also in both types of people, their blood glucose levels can rise too high
How is type 2 diabetes treated
Type 2 diabetes is often treated with a diet containing a controlled level of carbohydrates.
The aim of this is to prevent the blood glucose concentration from rising too high
People with type 2 diabetes are also advised to take exercise (regime)
What is a major risk factor for Type 2 diabetes
Obesity is a risk factor for Type 2 diabetes.
As obesity levels are increasing in the UK, we are seeing more people with type 2 diabetes
What is obesity in regards to type 2 diabetes
Obesity is a risk factor for Type 2 diabetes.
Why are people with type 2 diabetes advised to exercise
Fsl: Type 2 diabetes is often linked to obesity so regulation of body weight is important. Also, exercise uses glucose by respiration, helping to regulate blood glucose levels.
____________
Obesity is a risk factor for Type 2 diabetes so exercise should be done to regulate body weight (which is important)
Also during exercise, muscle cells need energy to contract, therefore more respiration occurs, which uses up the glucose in the process (more glucose is broken down), helping to regulate blood glucose levels.
Evaluate information
around the relationship
between obesity and
diabetes, and make
recommendations taking
into account social and
ethical issues.
social issues include the fact that healthy food is sometimes more expensive than calorific convenience food so people can’t always afford it. Also some people do not live near any shops where they can easily buy good quality food (these are called food deserts).
An ethical issue could be is it acceptable to tell a person what they should and should not eat and whether they are overweight?
What could cause the blood glucose concentration to fall
Blood glucose concentration can fall in between meals
Describe what happens if the blood glucose concentration is too low
If the blood glucose concentration is too low, this (blood glucose concentration) is detected by the pancreas.
Pancreas releases the hormone glucagon into the bloodstream.
Glucagon (causes) triggers (liver) cells to convert glycogen stores back to glucose and this glucose is released into the blood
This causes the blood glucose concentration to return to normal
explain why the graph looks like this
https://www.youtube.com/watch?v=77oyUdNZ054&list=PL9IouNCPbCxW3lptxS1yHCP2I9YDfM2co&index=10
5:07
A persons blood glucose concentration (this person does not have diabetes)
A persons blood glucose concentration (this person does not have diabetes)
The blood glucose concentration rises slightly and falls slightly over the course of the day
This is because the blood glucose concentration is controlled by a balance between insulin and glucagon
If the glucose concentration rises, then the pancreas detects this change and releases insulin and this causes the glucose concentration to fall.
However, when the glucose concentration falls to a certain level, the pancreas detects this and releases glucagon. This causes the glucose concentration to rise again
Because insulin and glucagon have opposite effects on the blood glucose concentration, they form a negative feedback cycle
explain how glucagon interacts
with insulin in a negative feedback cycle to control blood glucose (sugar)
levels in the body
A persons blood glucose concentration (this person does not have diabetes)
The blood glucose concentration rises slightly and falls slightly over the course of the day
This is because the blood glucose concentration is controlled by a balance between insulin and glucagon
If the glucose concentration rises, then the pancreas detects this change and releases insulin and this causes the glucose concentration to fall.
However, when the glucose concentration falls to a certain level, the pancreas detects this and releases glucagon. This causes the glucose concentration to rise again
Because insulin and glucagon have opposite effects on the blood glucose concentration, they form a negative feedback cycle
what is glucose
The (a simple) sugar used in respiration
what is glycogen
A storage carbohydrate found in the liver and muscles
A molecule that acts a store of glucose in the liver and muscle cells
what is glucagon
a hormone that stimulates the liver to break down glycogen to glucose (hormone involved in the control of blood sugar levels)
what is insulin
hormone made in pancreas that causes glucose to pass from blood into
cells, where it is needed for respiration (hormone involved in the control of blood sugar levels)
Why is it so important to control the level of glucose in your blood
Glucose needed for cellular respiration,
releasing energy for body’s metabolic reactions.
Too much or too little glucose in blood causes problems with
respiration
people with diabetes have to monitor the amount of carbohydrate in their diet. explain why
Carbohydrate broken down into glucose,
so the more carbohydrate-rich food that is eaten, the higher blood glucose levels will rise
and the harder it is for insulin injections to maintain safe and healthy blood glucose levels.
