Biology Paper 2 homeostasis and response Flashcards
Define the term homeostasis
This is the regulation of the internal conditions of the cell or organism to maintain optimum conditions for function and response
What does CNS mean and what does it consist of?
CNS means central nervous system and consists of the brain and the spinal chord
What is the definition of a neurone?
a neurone carries an electrical impulse from one end to another
What is meant by a reflex arc?
This is a nervous response that is that is fast and automatic and does not involve the conscious brain
What is a synapse?
a synapse is a gap between 2 neurones across within a chemical must diffuse to trigger an electrical impulse to the second neurone
What is meant by a chemical response?
This response use hormones which travel into the bloodstream to a target organ to make slow, longer lasting changes
What is the endocrice system and what does it consist of?
It consists of glands which secrete hormonesin the bloodstream.
What is insulin?
Insulin is produced in the pancreas and is used to decrease glucose levels in the blood
What is glycogen?
Glycogen is the long term store of sugar in the body, it is made and stored in the liver and muscles.
Define the term accomodation?
This is the process of changing the lens shape to focus on near or distant objects.
Define auxin
Auxin is the hormone that controls the plant response to light and gravity.
what is a nervous response?
it uses electrical impulses in nerves to make fast short lived changes.
what is a stimulus?
a stimulus is a change in the environment.
what is a receptor?
A receptor is a type of cell that detects stimuli
What is a sensory neurone and what does it do?
A sensory neurone is a neurone that carries electrical impulses from the CNS to the effectors.
What is a motor neurone?
a motor neurone is a neurone that carries electrical impulses from the CNS to the effectors.
What is an effector?
These are muscles or glands which bring about responses to restore optimum levels
What does the thyroid do?
It releases thyroxine which plays an important role in growth and development.
What does FSH do and where is it released from?
It is released from the pituatary gland, it causes an egg to be matured in the ovary, it also tells the ovaries to release oestrogen.
What does oestrogen do?
Oestrogen stops the production of FSH so that only 1 egg matures in a cycle and it helps repair and thicken the uterus lining and it stimulates the pituatary gland to release LH.
What does LH do?
It triggers the release of a mature egg.(ovulation)
What does progesterone do?
It maintains the uterus lining during the middle of the menstual cycle and during pregnancy.
Define myopia?
Myopia is a condition(short sightedness) where light rays are focussed in front of the retina so objects are not seen clearly.
Define hyperopia?
Hyperopia is acondition(long sightedness) this is where the light rays are focussed behind the retina so objects are not seen clearly.
