B10 Flashcards
What are the conditions inside your body called?
The internal environment
Why is it important to keep your internal environment constant?
So your organs can work correctly
What are the 3 conditions of the internal environment that need to be balanced?
Water and ions
Blood sugar
Temperature
How does your body detect a change in the internal environment?
Sense organs form part of the nervous system and contain many specialised cells called receptors. If a receptor detects a stimulus (change) then it sends an electrical impulse to a sensory neurone. The electrical impulse travels along the sensory neurone to the CNS, which makes sense of the electrical impulse and sends impulses to the effectors (muscles/glands) via the motor neurones
What are 5 examples of types of receptors/ sense organs and what do they detect?
Eye - Light
Ear - Sound + Balance
Tongue - Chemicals
Nose - Chemicals
Skin - Touch, Temperature, Pressure, Pain
The nervous system uses…
whereas
Chemical responses use…
The nervous system uses electrical impulses to send signals through the neurones
WHEREAS
Chemical responses use the hormonal system and chemical messengers carried in the bloodstream
List factors that determine the nervous system
Electrical signal
Transferred by neurones
Effectors are muscles or glands
Type of response is muscle contraction or secretion
Rapid response speed
Short duration (until nerve impulses stop)
List factors that determine the hormonal system?
Chemical signal
Transferred by the bloodstream
Effectors are target cells in particular tissues
Type of response is a chemical change
Slower response speed
Long duration (until hormone is broken down by the liver)
What are the 2 types of reflex actions?
Voluntary and Reflex
What are key factors of a voluntary reflex?
You have control over
Happens consciously
Intentional
Effectors are muscles or GLANDS
Nerve impulses always reach the brain
Action initiated by the brain
Can be learnt
Takes longer
What are key factors of a reflex?
You have no control over
Happens subconsciously
Unintentional
Effectors are muscles
Nerve impulses don’t reach the brain
Action initiated by muscle receptor
Can’t be learnt
Why are reflex actions important?
They help protect us from danger and harm
Name some examples of reflex actions
Pulling away if we touch something hot/cold
Coughing
Blinking
Breathing
What is the reflex arc?
The sense organ, sensory neurone, relay neurone, motor neurone and effector organ which brings about a reflex action
What is a synapse?
The connection between two neurones
How do synapses work?
1) An impulse arrives at the end of the presynaptic neurone
2) Vesicles move forward and fuse with presynaptic membrane
3) Neurotransmitter is releases into the synaptic cleft
4) Neurotransmitter diffuses across synaptic cleft
5) Neurotransmitter attaches to receptors on postsynaptic membrane
6) This triggers an impulse along the postsynaptic neurone
7) The neurotransmitter is recycled/destroyed once an impulse is sent
What is the brain responsible for?
Complex behaviours. Everything you do
What is the brain?
The swollen end of the spinal cord that controls and coordinates the entire nervous system