Nervous system and Hormones Flashcards
What is a stimulus?
A change in the environment
What is a receptor
a group of specialized cells that detect a stimulus
found in sensory organs
Expand CNS
Central Nervous System
What is a co-ordinator
Links a receptor to an effector
What is an effector
part of the body which responds to the stimulus
What is a response?
A response is a reaction to the stimulus
What are nerves also called as?
Neurons
Explain neurons
carry information in small electrical signals called impulses
often grouped in large bundles called nerves
How does a stimulus result in a response?
Stimulus —> Receptor —> CNS/Co-Ordinator—>Effectors—>Response
What is the CNS made up of?
Brain and Spinal Cord
Explain some features of the nervous system
Acts all over the body
Short term
Very fast response
Communicates to the body through electrical impulses via neutrons
Explain some features of Hormones
Slow response
Long Term
Acts on a target organ
Communicates to the body via blood
How are neurons adapted to their function
Branched structures at each end to allow electrical signals to pass
Explain Synapses
The small gap between neurons which impulses jump across
Describe Voluntary Actions
When the brain is involved in thinking about an action
Involves conscious thought
slower response
Describe Reflex Actions
Automatic and fast response to the stimuli, does not involve the brain or conscious thought
Involves the spinal cord
What are the two types of Effectors?
Muscles and Glands
What is a reflex arc?
The pathway of neurons in a reflex action is described as reflex arc
What is a Sensory Neuron?
Carries impulses from the receptor to the spinal cord
What is Motor Neuron?
Carries nerve impulses from spinal cord to the effector
What is a association neuron?
Joins the sensory and motor neuron
What are Hormones?
Hormones are chemical messengers, produced by glands that travel in the blood to bring about a response in a target organ
What is Insulin
Insulin is the hormone that lowers blood glucose concentrations