Biology Paper 2: Homeostasis and response Flashcards
What is the receptor in homeostasis?
Cells which detect stimuli / change in environment
What is the effector in homeostasis?
A muscle or gland that will bring about response.
What is the order in the maintenance of homeostasis homeostasis?
Stimulus
Receptor
Sensory neuron
Coordination centre
Motor Neuron
Effector
Response / Feedback mechanism
How does the nervous reflex work?
When a stimulus is felt
The receptors feel the stimulus.
Which sends electrical signals that travel through the sensory neuron to the spinal cord.
In the spinal cord there is a relay neuron which allows the electrical signal to travel to the correct motor neuron which can be connected to a gland or muscle that causes it to contract or move.
Name 3 common nervous reflexes.
Blinking
Breathing
Sneezing
What are the gaps that links 2 nerve cells.
Synapse
What happens at the synapse?
When an electrical impulse is sent to the end of a neuron.
It triggers the release of chemical neurotransmitter molecules.
Which move towards the membrane and fuse with them to release chemical transmitter molecules.
Which diffuse to the start of the other neuron.
That causes another electrical impulse to be generated.
What is negative feedback?
A homeostatic mechanism that occurs when the body detects a change and makes an adjustment to return itself to normal.
What does the coordination centre consist of?
The brain and spinal gland.
What is the function of the relay neuron?
They are located in the Coordination centre where they carry signals between sensory and motor neurons.
What are the disadvantages to your body having lower thyroxine?
Lower metabolism
Lower protein synthesis levels
Where is thyroxine released?
Thyroid gland.
How does the brain maintain ideal thyroxine release when thyroxine levels decrease or increase?
Electrical signals are sent to the brain.
Which determine whether the pituitary gland needs to release more / less thyroxine stimulating hormone.
What are the effects of adrenalin being released.
Increased heart rate allows more oxygen pumped to muscles / cells.
Increased breathing rate allows more oxygen to the blood.
Glycogen reserves in muscle cells break down to release glucose for increased respiration.
Blood from digestive system redirected to skeletal muscles.
Pupils dilate allows more light in.
How does the brain release adrenalin to flight / fight response?
Brain sends signals to the adrenal gland to release adrenalin.
Not negative feedback.
What happens when the amount of thyroid stimulating hormone released from the pituitary gland increases?
More thyroxine is released from the thyroid, metabolic rate increases.
Why is it important that adrenalin does not use a negative feedback loop?
once the danger/stress is over, normality is re-established [1] reduces the body’s energy consumption (the body uses a lot of energy during the ‘“fight or flight” response. [1]
What is homeostasis?
The maintenance of a constant internal environment at optimal conditions.
What are the 3 main components of homeostasis?
Receptor
Coordination centre
Effector
How do hormones travel in the endocrine system?
The blood.
How does the pancreas maintain glucose levels when blood glucose RISE?
Receptor cells in the pancreas detect a rise.
Insulin is released to the liver and muscles.
Which convert the glucose to glycogen.
Causing blood glucose to fall.
How does the pancreas maintain glucose levels when blood glucose FALLS?
Receptor cells in the pancreas detect the fall.
Glucagon is released.
Which causes the glycogen to break down to glucose in the level.
Causing blood glucose to rise.
Name one function of glucose in the body.
Provides energy
Where is the FSH and what does it do?
Produced in the Pituitary gland.
Stimulate oestrogen release
Matures eggs
