B5.3. Hormonal control in humans Flashcards
What is the endocrine system composed of?
Glands which secrete chemicals called hormones.
How is a chemical “message” transported to the target organ in animals?
Via the bloodstream.
Compare the speed and duration of hormonal control to nervous control.
(Hormonal) Slower but act for longer.
What is referred to as the “master gland”?
The pituitary gland.
Name the gland which produces human growth hormone and is found within the brain.
Pituitary gland
Name the gland which produces many digestive enzymes.
Pancreas
Name the gland which produces testosterone.
Testes
Name the gland which produces thyroxine.
Thyroid
Name the gland which produced adrenaline.
Adrenal gland
Name the gland which produces hormones such as oestrogen and progesterone.
Ovary
What is monitored for changes in glucose concentration?
The blood.
What controls the response to changes in blood glucose concentration?
The pancreas.
What is produced if the blood glucose concentration is too high?
Insulin, a hormone.
State two ways insulin helps to lower blood glucose concentration.
Causes glucose to move from the blood to the cells AND triggers the conversion of glucose into glycogen.
What is produced if the blood glucose concentration is too low?
Glucagon, a hormone.
State how glucagon helps to increases blood glucose concentration.
Triggers the breakdown of glycogen into glucose, which is released into the blood.
Name two places in the body glycogen is stored.
Muscle cells and the liver.
What is the process called which responds to a change from the normal levels in the body by restoring them back to the normal levels?
Negative feedback.
Type 1 diabetes is caused by…..
An inability to make insulin in the pancreas.
Type 2 diabetes is caused by….
A lack of response by cells to insulin.
What happens to human cells if they lose too much water?
Shrivel and eventually die.
What happens to human cells if they gain too much water?
Swell and eventually burst (lyse).
Name two ways other than excretion in which water is lost from the body.
Exhalation from the lungs AND sweat from the skin.
In addition to water, what else is lost via sweat?
Ions and urea.
What is removed from the body by the kidneys via urine?
Excess water, excess ions and urea.
Excess amino acids are broken down into….
Ammonia.
Within the body, ammonia is immediately converted to what?
Urea.
Where does the conversion of ammonia into urea occur?
The liver.
Which hormone controls the water balance of the body and where is it made?
ADH (Anti-diuretic hormone)
Which part of the kidney does ADH affect?
The kidney tubule walls.
When is ADH released?
When the cells lose too much water.
What is the effect on urine concentration and volume when ADH is released?
Higher concentration, lower volume.
What is the effect on urine concentration and volume when ADH is NOT released?
Lower concentration, higher volume.
How does ADH affect the walls of kidney tubules?
Increases the number of aquaporin channels, increasing the volume of water reabsorbed into the blood.
State two methods of treating kidney failure.
Dialysis and kidney transplant.
Name the main female hormone involved in development and reproduction.
Oestrogen.
Name the main male hormone involved in development and reproduction.
Testosterone.
What does testosterone cause to happen in men?
Stimulates sperm production.
Approximately how often is an egg released from the ovaries in a female and what is this process called?
Every 28 days, ovulation.
What does the release of FSH cause?
Maturation of an egg in the ovaries.
The release of which hormone stimulates the release of an egg from the ovaries?
Luteinising hormone (LH).
Which hormones are involved in the maintenance of the uterus lining?
Oestrogen and progesterone.
How do oral contraceptives containing hormones prevent pregnancy?
Inhibits FSH production so no eggs mature
How does an injection, implant or skin patch containing slow-release progesterone prevent pregnancy?
Inhibits the maturation of eggs
How do barrier methods, such as condoms and diaphragms, prevent pregnancy?
Prevents the sperm reaching the egg
How do intrauterine devices prevent pregnancy?
Prevents the implantation of an embryo AND/OR release hormones
How do spermicidal agents prevent pregnancy?
Kills or disable sperm
How does abstaining from sexual intercourse prevent pregnancy?
Reduces the chance of sperm meeting an egg in the oviduct
How does surgical sterilisation prevent pregnancy?
Prevents sperm or eggs being release by the male or female
Name the two hormones given to women to increase fertility.
FSH and LH.
Detail the four steps in IVF treatment.
“1. The mother is given FSH and LH to stimulate the maturation of several eggs
- The eggs are collected from the mother and fertilised by sperm from the father in the laboratory
- The fertilised eggs develop into embryos.
- At the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb).”
State three drawbacks to IVF treatment.
“1. It is very emotionally and physically stressful
- The success rates are not high
- It can lead to multiple births which are a risk to both the babies and the mother”
State one positive of IVF treatment.
It allows pregnancy when previously not possible.
Name the hormone which controls the “fight or flight” reaction in humans.
Adrenaline
Explain two effects adrenaline has on the body.
“Increases heart rate.
Therefore increases delivery of oxygen and glucose to the brain and muscles.”
Where is thyroxine made?
Thyroid gland.
What does thyroxine do in the body?
Increases the basal (base) metabolic rate, therefore increasing growth and development.