Nervous System And Responding To Stimuli- Humans- Coordination And Response Flashcards
(40 cards)
What is a stimulus?
Any change in external environment
What is a receptor?
- They detect stimuli
-receptors in the sense organs are groups of cells that detect about a response to a stimuli
What is an effector?
- cells that bring about a response to stimuli
- includes muscle cells found in the glands. They respond with either muscle cells contracting or glands secreting hormones
How do receptors communicate with the effectors?
Through the nervous system or the hormonal/endocrine system
What does the nervous system consist of?
- made up of nerve cells that carry impulses around the body- sensory neurone, relay neurones, motor neurones.
What consists of the endocrine/hormonal system?
- made up of glands that produce hormones that stimulate changes in the body
Similarities between the endocrine/hormonal system and the nervous system
- both require stimuli, receptors and effectors
-chemicals involved in both
What does the central nervous system consist of?
- brain and spinal cord
- allows us to make sense of our surroundings and respond in order to survive
Describe the pathway of an electrical impulse from a stimulus to a response in the nervous system, including the role of the CNS.
1) Receptor cells in sense organs convert a stimulus (such as a bright light) into an electrical
impulse.
2) This electrical impulse travels along cells called sensory neurons to the central nervous system (CNS).
3) in the central nervous system the information is processed and the appropriate response is coordinated, resulting in an electrical impulse being sent along motor neurons to effectors.
4) The effectors carry out the response (this may be muscles contracting or glands secreting
hormones).
Differences between the nervous system and the endocrine/hormonal system
Nervous-
- electrical signals ( impulses)
- nerve cells as transmitter
-very fast response
-short duration of response
Endocrine/hormonal system-
- chemical signals
-transmits hormones in the bloodstream
-slower response
long duration of the response
-
How do neurones transmit information?
- stimulation of receptors in the sense organs sends high speed electrical impulses along nerves into and out of the nervous system- able to bring about very rapid responses
Where are sensory receptors found in?
Sense organs
What are the main sense organs?
- eye- vision
-ear- hearing and balance - tongue- taste
-nose- smell
-touch- pressure, temperature and pain - muscles- stretch and receptors
What is a sensory receptor?
Give you information about changes in the world around you and inside your body. They transform energy from one form to another. They are inside sense organs.
What are synapses
- a connection between two neurones
- transmission of impulses across the synapse and uses neurotransmitters
Describe how an electrical impulse is transmitted across a synapse
•Electrical impulse travels along the axon of the first neuron.
•This triggers nerve endings to release neurotransmitters.
•The electrical impulse cannot cross the synapse, so it is converted into a chemical signal.
•Neurotransmitters diffuse across the synapse to the next neuron.
•They bind to receptor molecules on the second neuron.
•This stimulates a new electrical impulse in the second neuron.
What are neurotransmitters?
-chemicals released at one end of a nerve fibre
Three types of neurones
- sensory neurone
-motor neurone
-relay neurone
Role of motor neurones
Motor neurones transmit messages from the brain and
spinal cord to the muscles and glands.
Role of sensory neurones
Sensory neurones transmit messages from sense receptors, such as the eye or nose, to the brain or spinal
cord.
Role of relay neurones
• Found in the CNS (brain and spinal cord).
• Transmit impulses between sensory and motor neurones.
• Allow communication within reflex arcs and complex pathways.
• Help process and coordinate responses to stimuli.
What is a reflex
A reflex is an automatic and involuntary reaction to a certain stimulus (e.g., pulling your hand away from something hot).
What is a reflex arc
the pathway the electrical impulse travels through in the CNS, from the sensory neuron to the relay neuron (in the spinal cord), and then to the motor neuron to cause the response.
Process of the reflex arc
- Stimulus: Something happens (e.g., touching something hot).
- Receptor: Sensory receptors in the skin detect the stimulus (e.g., heat).
- Sensory Neuron: The sensory neuron carries the electrical impulse to the spinal cord (CNS).
- Relay Neuron: The impulse is passed through a relay neuron in the spinal cord.
- Motor Neuron: The motor neuron carries the impulse from the spinal cord to the effector (e.g., muscles).
- Effector: The muscle contracts to pull your hand away.
This is an automatic, involuntary response that doesn’t require your brain’s involvement.
