Chapter 17 - Hormones Flashcards
What are hormones?
Chemical substances that are produced by specialised cells called glands, which are found in certain organs.
The body has two systems of control for the body, what are they called?
The nervous system and the endocrine system.
Where are hormones secreted and why?
Into the blood so that they become available to all parts of the body.
What is required so that cells can respond to hormones?
Specific receptors that hormones can bind to
Which organs contain cells with the required receptors?
Target organs.
What is different about the hormonal system versus the nervous system?
Hormones can have an effect over long periods, whereas nervous responses are short-lived.
What is a benefit of hormones being secreted directly into the blood?
They can coordinate responses from several body systems at the same time.
Give an example of a hormone that has May different target organs.
Testosterone.
Give an example of a hormone that has only one target organ.
ADH (only affects the kidneys)
Complete the sentence:
Hormones often influence the production of other ________, so a ________ can also be a target organ.
- Hormones
2. Gland
What is the purpose of the hormone FSH, and where is it made?
FSH is made by the pituitary gland, and controls egg development in women.
What hormone controls the production of FSH?
Oestrogen.
Which hormones are produced by the ovaries?
Oestrogen and progesterone.
Which hormone is produced by the testes?
Testosterone.
Which hormone is produced by the adrenal glands?
Adrenaline, which is central to the fight or flight response.
Which hormones are produced by the pancreas?
Insulin and glucagon (controls blood sugar)
Which hormone is produced by the thyroid?
Thyroxine, which controls metabolic rate.
Which hormones are produced by the pituitary gland?
Many, including: Growth hormone, ADH (urine production), LH and FSH (reproductive hormones)
What is meant by the term ‘homeostasis’?
Maintaining specific conditions in the body within set boundaries. ‘The maintenance of a steady state in an internal environment.’
Which factors are critical to homeostasis?
- Body temperature (36-38 degrees)
- Blood glucose levels (82-110mg/dL)
- Blood pH (7.35-7.45)
- Concentration of ions (e.g. sodium, potassium, and chloride)
- osmoregulation (amount of water in the blood and tissues)
Why is homeostasis critical to chemical reactions?
- They must take place in aqueous solution. Water moves in and out of cells depending on the concentration of substances dissolved in it (especially salt and sugar)
- They are controlled by enzymes, which only work effectively within narrow ranges of temperature and pH.
What causes blood glucose to rise?
Eating
What causes blood glucose to fall?
Exercise
What risks are associated with blood glucose that is too high or too low?
Heart failure
Kidney failure
Coma
Death
Where is excess glucose stored after meals?
In the liver and muscles
What happens to those stores between meals?
They are gradually released back into the blood to prevent levels falling too low.
Which organ monitors blood glucose levels?
Pancreas
What do insulin and glucagon do?
Tell the liver and muscles what to do
What does the pancreas produce if it detects high blood glucose?
Insulin
What does the pancreas produce if it detects low blood glucose?
Glucagon.
What effect does insulin have on the liver and muscles?
It causes them to take up glucose and convert it into a storage molecule called glycogen.
What effect does glucagon have on the liver and muscles?
It causes them to break down glycogen and release it as glucose back into the blood.
What is negative feedback?
When a change is identified, and action is taken to return the body to its optimum state.
What is diabetes?
The inability to control blood glucose concentration.
How many people are affected by diabetes in the UK?
3.8 million
Which organs are damaged by uncontrolled diabetes?
Kidneys
Heart
Brain
Eyes
What is diabetic ketoacidosis and what does it cause?
Diabetic crisis. Causes:
Vomiting Stomach pains Rapid breathing Increased pulse Sleepiness Dry mouth Flushed face Fruity breath
What are the health risks of diabetes?
- Stroke
- Eye damage
- Heart attack
- Kidney damage
- Impotence/difficulty passing urine
- Numbness and reduced blood supply to feet
What causes type 1 diabetes?
It is an autoimmune disease in which the immune system attacks the beta cells in the pancreas which produce insulin. Consequently, no insulin is produced.
How is type 1 diabetes treated?
Insulin is injected into the subcutaneous fat several times a day.
What factors affect the amount of insulin required?
How much food is consumed, and how much exercise is taken. The blood should be tested to establish blood glucose level before insulin is administered.
What causes type 2 diabetes?
Insulin resistance.
What are risk factors for developing type 2 diabetes?
- Runs in families
- Diet high in sugar
- Lack of exercise
- Obesity
What is the formula for calculating BMI?
Weight in kilograms divided by height in metres squared.
What are the adult BMI categories?
Less than 18.5 = underweight
18.5-24.9 = normal
25.0-29.9 = overweight
30+ = obese.
What is the wait to hip ratio threshold for greater risk of developing type 2 diabetes in men and women?
Men= 0.95 Women= 0.86
What is the treatment for type 2 diabetes?
Exercise
Healthy diet low in sugar
Weight loss
Drugs
