6A - Stimuli and Responses Flashcards
What types of changes do animals respond to?
Changes in:
• External environment
• Internal environment
Why do animals respond to changes in external environment?
To increase their chances of survival (e.g. by avoiding hazards).
Why do animals respond to changes in their internal environment?
To make sure that conditions are optimal for metabolism.
Do plants respond to changes in their environment?
Yes
What is a stimulus?
A change in the internal or external environment.
What detects a stimulus?
A receptor
What are receptors?
Cells or proteins on cell membranes that detect a stimulus.
Can receptors detect more than one type of stimulus?
No, they are specific to one type of stimulus.
What are effectors?
Cells that bring about a response to a stimulus.
What are the two ways receptors can communicate with effectors?
Via the:
• Nervous system
• Hormonal system
What is the nervous system made of?
A complex network of cells called neurones.
What are the types of neurones?
- Sensory neurones
- Relay neurones
- Motor neurones
What are sensory neurones?
Neurones that transmit electrical impulses from receptors to the CNS.
What are relay neurones?
Neurones that transmit electrical impulses from the sensory neurones to the motor neurones.
What are motor neurones?
Neurones that transmit electrical impulses from the CNS to effectors.
What are neurones?
Cells that transmit electrical signals.
Describe the path of an electrical signal in a non-reflex reaction.
Stimulus -> Receptor -> Sensory neurone -> CNS -> Motor neurone -> Effector -> Response
What does the CNS do in a non-reflex reaction?
- It acts as a coordinator
* Processes the information and sends impulses along motor neurones
What is the nervous system split into?
- Central nervous system (CNS) -> Brain + Spinal cord
* Peripheral nervous system
What is the CNS made up of?
Brain and spinal cord
What is the peripheral nervous system made up of?
The neurones that connect the CNS to the rest of the body
What are the two systems of the peripheral nervous system? What does each do?
- Somatic nervous system -> Conscious activities
* Autonomic nervous system -> Unconscious activities
What are the two divisions of the autonomic nervous system? What does each do?
- Sympathetic nervous system -> Gets the body ready for action (“flight or fight”)
- Parasympathetic -> Calms the body down (“rest and digest”)
Describe the entire structure of the nervous system with subdivisions.
Nervous system is split into:
• CNS
• Peripheral nervous system
Peripheral nervous system is split into:
• Somatic nervous system
• Autonomic nervous system
Autonomic nervous system is split into:
• Sympathetic nervous system
• Parasympathetic nervous system