Response and regulation Flashcards
What are the central nervous systems?
Brain and Spinal chord
What is each sense organ made out of?
special cells called receptors
What are receptors?
Receptors collect info and pass info as electrical impulses along neurons to central nervous system
What is the order of the reflex arc?
Stimulus
Receptor
Sensory neurone
Co-ordinator/ relay nerve
Motor neurone
Effector (muscle or gland)
Response
What is an example of the reflex arc?
Bright light
Eye
Sensory nerve (optic nerve)
Relay nerve
Motor nerve
Iris
Pupil contracts
What is the purpose of blinking?
Protection of the eye
What is the purpose of a knee jerk?
Maintaining posture
What is glycogen?
Storage form of glucose in the liver
What is glucagon?
Hormone, raises blood glucose when low
What is insulin?
Hormone, lowers blood glucose when high
Where is glucagon and insulin stored/created?
In the pancreas
What causes high blood glucose?
Eating food containing sugar
What lowers blood glucose?
Respiration/ exercise
How does low blood glucose go back to normal?
Glucagon is released from the pancreas (glycogen in liver to glucose in blood)
How does high blood sugar go back to normal?
Insulin is released from the pancreas (glucose in blood to glycogen in liver)
e.g eating carbs
normal glucose level in blood - carbs eaten - glucose level in blood goes up - pancreas starts releasing insulin in blood - liver starts turning glucose into glycogen and storing - glucose level in blood back to normal - pancreas stops releasing insulin
What are the factors of type 1 diabetes?
genetics, no insulin produced, not able to convert glycogen
What are the factors of type 2 diabetes?
lifestyle and not enough insulin produced
What are the treatments to diabetes?
- regular injections of insulin (into bloodstream)
- controlling carb and fat content of a diet
- possible transplant of pancreatic tissue
What is tropism?
The growth of a plant towards a light source or in a response to a source of gravity
Define gravetropism.
(response to gravity)
- roots grow down (positive) - make sure they find soil and water
- shoots always grow up (negative) - make sure they always reach light
Define phototropism
grow towards light to maximise photosynthesis
What is the hormone that controls a plant’s responses to light and gravity?
Auxin
Where are the two places auxin is made and how do they effect growth?
At the tips of stems and roots
Growth is sped up in stems
Growth is slowed down in roots