Biology Homeostasis & response Sept 2018 Flashcards
What is the definition of homeostasis?
Homeostasis is the maintenance of a constant internal environment
What conditions does your body need to keep stable in order to survive?
- Body glucose concentration
- Body temperature
- Water balance
What is the CNS?
The Central Nervous System is the name given to the brain and spinal chord as they are the bridge carrying nerves.
What is a receptor?
A receptor is a cell or group of cells at the beginning of a pathway of neurons that detects a change and sends an electrical impulse
What are the three types of neurons?
Sensory, relay and motor
What is the sensory neuron?
A neuron that carries an electrical impulse from a receptor towards the CNS
What is a relay neuron?
A neuron that carries an electrical impulse around the CNS
What is a motor neuron?
A neuron that carries an electrical impulse away from the CNS to a effector
What is an effector?
A muscle or gland
What is the synapse?
A gap between the axon of one nerve and the dendrites of another where chemical neurotransmitters transmit the impulse
What is a dendrite?
The branched beginnings of neurons, which can detect chemical neurotransmitters and start another impulse
What is an axon?
The root like part of a neuron where chemical neurotransmitters are sent through the synapse.
What is a reflex response and reflex arc?
Reflex response - An automatic response that you do
not think about.
Reflex arc - The route of an electrical impulse that
avoids the brain to save time so helps
prevent damage to your body.
What is the cerebral cortex?
The outer layer of the brain, which plays an important role in consciousness.
What is the cerebellum?
A part of the back of the brain that coordinates muscular activity.
What is the medulla oblongata?
A part of your brain above the spinal chord that controls your breathing and heart rates.
What is accommodation?
Changing the shape of the lens in your eye to focus on near and far objects.
What are cones and rods?
Cones - Light-sensitive receptor cells on your retina in
the back of your eye that let you see in colour.
Rods - Light-sensitive receptor cells on your retina in
the back of your eye that let you see in low
light conditions.
What are the parts of the eye and their functions?
Cornea - Refracts light through the pupil. (transparent
part of eye)
Lens - Refracts light to be focused on the retina.
(biconvex structure found behind the pupil)
Iris - Controls the size of the pupil by relaxing and
contracting. (coloured part of eye)
Ciliary Body - Relaxes and contracts to change the
shape of the lens during accommodation.
Choroid - Provides oxygen and nourishment to the cells
of the retina.
Retina - The layer of receptors in your eye containing
two types of light sensitive cells called rods
and cones.
Fovea - Responsible for your sharpest vision.
Sclera - The white of the eye. Protects the eye.
Optic nerve - Connects the eyes with the brain.
