B11 - Hormonal Coordination Flashcards
What is the endocrine system made up of?
Glands that secrete chemicals called hormones directly into the bloodstream
Where does the bloodstream carry hormones in general?
The bloodstream carrys these hormones to target organs - to produce an effect
What are hormones?
- Hormones are chemical messengers that control the growth, differentiation, and metabolism of specific target cells.
- The hormones travel around the body, via. The bloodstream - carried the hormones set to effect the target organs.
How do hormones trigger a response?
Target organs have receptors on the cell membrane –> which pick up the hormone molecules
What are the main glands involved in the endocrine system? (6 marks)
- Pituitary gland
- Thyroid gland
- Pancreas
- Ovaries
- Testes
- Adrenal glands
What are the key differences between the NERVOUS system and the ENDOCRINE system?
- NERVOUS system:
- Involves electrical impulses –> rapidly transported by neurons
- Short lived - temporary response can be voluntary and involuntary - ENDOCRINE system:
- Chemical coordination –> slowly transported by the bloodstream
- Short or long lived - can be permanent and involuntary response.
What are examples of Hormones that have a rapid response?
- Insulin
- Adrenaline
What are examples of slow-acting hormones with long-term effects?
- Growth hormones
- Sex hormones
What is the Pituitary Gland and where is it found?
The pituitary gland is also known as the master gland - it is found in the brain and coordinates other glands.
What does the pituitary gland do?
- Secretes a variety of hormones into the blood - such as: FSH (Follicle Stimulating Hormone) and LH (Lieutenising Hormone) - in response to change or either have an effect on the body
OR
- Act on other glands to stimulate them to produce different hormones
What is FSH and what does it do?
FSH = Follicle Stimulating Hormone
- Causes the maturation of an egg in an ovary within a structure called follicles to stimulate the ovaries to make the female sex hormone - oestrogen
Where is FSH produced?
FSH is produced in the pituitary glands in the brain
What is TSH and what does it do?
TSH = Thyroid Stimulating Hormone
- TSH stimulates the thyroid gland to make THYROXINE, this helps control the rate of metabolism, heart rate and temperature.
Where is TSH produced?
In the pituitary gland
What is the main role of the pituitary gland?
- To control the growth in children
- Stimulates the thyroid gland to make thyroxine to control the rate of metabolism
- In women, it stimulates ovaries to produce and release eggs - makes LH (Lieutinising Hormone) and makes the female sex hormone - oestrogen - levels rise.
What is the main role of the thyroid gland?
- Secretes thyroxine
- Controls the basal metabolic rate if the body –> this is important for growth and development.
What is basal metabolic rate?
The basal metabolic rate is how quickly substances are broken down and built up - for example: how much oxygen your tissues use and how the brain of a growing child develops.
What is the main role of the pancreas gland?
- Secretes insulin
- Controls the levels of glucose in the blood
What is the main role of the adrenal glands?
- Secretes the hormone: adrenaline
- Prepares the body for stressful situations - initiates humans - ‘fight or flight response’
What is the main role of the glamds in the ovaries?
- Secretes oestrogen (female sex hormone) and progesterone
- Control the development of the female secondary sexual characteristics –> imvolved in menstrual cycle.
What is the main role of the glands in the testes?
- Secretes testosterone (male sex hormone)
- Controls the development of male secondary characteristics and is involved in the production of the sperm
Why is it so important to control the blood glucose concentration?
Because glucose is needed by cells in order for respiration to occur
What is glucose?
Glucose! The sugar used in respiration
What is glycogen?
Glycogen: a storage carbohydrate found in the liver and muscles
What is glucagon?
Glucagon: a hormone that stimulates the liver to break down glycogen to glucose
Which organ/ gland detects and controls the change in blood glucose concentration?
The pancreas - as it monitors and controls blood glucose concentration
What increases the glucose levels in the blood?
Eating foods that contain high amounts of sugar or high concentrations of carbohydrates
Describe what happens when blood glucose levels are too high? (5 marks)
- Pancreas gland detects that blood glucose levels are too high
- Pancreas releases the hormone Insulin into the bloodstream
- Insulin travels in the bloodstream to the liver (and body cells)
- Body cells take in more glucose for respiration and the liver takes up excess glucose and stores it as glycogen
- Blood glucose levels are lowered and returned to normal homeostatic levels
Describe what happens when blood glucose levels are too low? (5 marks)
- Pancreas gland detects that blood glucose levels are too low
- The pancreas detects the drop in glucose levels and releases glucogon into the bloodstream
- The glucogon in the bloodstream makes its way down to the liver (and body cells)
- It binds with the glucose in the liver and creates glycogen and the excess is stored
- As a result, the blood sugar levels increase and return to normal homeostatic levels
What happens when the glycogen stores in the liver and muscles are too full?
Any excess glucose is converted to lipids and/or stored.
What decreases the glucose levels in the blood?
Rigorous activity exercise - uses glucose for respiration and/or fasting - i.e. not eating.
How is the blood glucose concentration kept constant?
By producing insulin and glucagon constantly at a narrow concentration range.
Explain how the blood glucose concentration links to the negative feedback loop?
If the blood glucose level is too low, the pancreas releases the hormone glucagon. This travels to the liver in the blood and causes the break-down of glycogen into glucose. The glucose enters the blood stream and glucose levels increase back to normal. This is an example of negative feedback
What causes Type 1 diabetes?
The pancreas does not produce enough insulin - blood glucose concentration is not controlled or genetic
What are some symptoms of Type 1 diabetes?
- Frequent urination - glucose is excreted with urine
- Unusual thirst
- Extreme hunger
- Unusual weight loss - breaking down fat and protein to use as fuel instead
- Extreme fatigue - lack of energy - glucose cannot get to cells
When does type 1 diabetes develop?
During childhood or adolescence
What causes Type 2 diabetes?
- Body cells no longer respond to insulin or less insulin than the body needs
What dies Type 2 diabetes link to?
- Obesity
- Lack of exercise
- Unhealthy lifestyle
When does Type 2 diabetes develop.
It is more common as people get older
How do you treat Tyoe 1 diabetes with insulin injections?
- insulin injection - replacement insulin before meals - insulin is a protein/hormone that would be digested in your stomach - so it is usually given as an injection because of its fast method to help lower blood sugar.
- The injected insulin allows glucose to be taken into body cells and converted into glycogen in the liver –> This stops the glucose in the blood getting too high.
- As the blood glucose levels fall, the glycogen is converted back into glucose and blood glucose levels are kept stable and returned to normal/optimum homeostatic levels in the body.
How else do you treat Type 1 diabetes?
- Caution about the levels of carbohydrates eaten
- A regular and balanced diet
- Exercise - keep the cardiovascular system healthy - which should be carefully planned to keep the blood glucose concentration steady
How have scientists and doctors attempted to cure Type 1 diabetes?
- Transplanting pancreatic cells that make insulin from both dead and living donors - limited success so far.
- Producing insulin - secreting cells from embryonic stem cells
- Genetic engineering - genetically engineering oancreatic cells
- These are all methods to minimise chances of rejection - so people (patients) are happy with the procedures, however, some people (for example, religious people or protestors) may think that the process is unethical.
How do you treat Type 2 diabetes if noticed early on?
- eating a balanced diet with carefully controlled amounts of carbohydrates
- losing weight
- doing regular exercise
- if on any medication, take it regularly in accordance with your schedule and doctors opinion
How do you treat more developed Type 2 diabetes?
There are drugs that:
- help insulin work better on the body cells
- help your pancreas make more insulin
- reduce the amount of glucose you absorb from your gut
- if these methods dont work (if its a severe case of Type 2 diabetes) then use insulin injections
What is negative feedback?
In negative feedback, the response will reverse or cause the opposite effect of the original stimulus. For example, internal regulation of body temperature
Where is thyroxine found?
The thyroid gland in your neck uses iodine from your diet to produce the hormone - thyroxine
What happens if levels of thyroxine in the blood begin to fall?
- Negative Feedback System
- the change/fall is detected by sensors in the brain –> so the amount of TSH released from the pituitary gland increases –> TSH stimulates production of thyroxine