Nervous Control (A-level Biology)
Nervous Control
The Nervous System
Organisation of the Nervous System
The nervous system is made up of 2 main parts.
- Central Nervous System. This is the brain and spinal cord.
- Peripheral Nervous System This is formed of the neurones, which connect the body to the central nervous system.
The peripheral nervous system can be further divided into:
- Somatic Nervous System. This controls any conscious activities carried out by the body, such as walking.
- Autonomic Nervous System. This controls any unconscious activities carried out by the body, such as pupil responses.
The autonomic nervous system can be further divided into:
- Sympathetic Nervous System. This is commonly known as the ‘fight or flight’ system. Adrenaline is involved with the sympathetic nervous system.
- Parasympathetic Nervous System This is commonly known as the ‘rest and digest’ system. Acetylcholine is involved with the parasympathetic nervous system.
The Brain
We’ll now explore 5 important brain structures.
- Hypothalamus. This controls temperature regulation and osmoregulation.
- Pituitary Gland. This releases hormones and is under the control of the hypothalamus.
- Medulla Oblongata. This controls the breathing and heart rate.
- Cerebellum. This controls balance and coordination of movement.
- Cerebrum. This controls the initiation of movement.
Receptors
Role of Receptors
- Receptors are specialised cells that detect physical stimuli and convert them into electrical signals. Each type of stimuli has a specific receptor – these can be cells or proteins.
- Receptors use energy from the stimulus to send Na+ ions (sodium ions) into the sensory neurones. This creates a voltage change in the neurone which is called a generator potential. Generator potentials can trigger action potentials, which is the method of how signals pass through the nervous system.
Still got a question? Leave a comment
Leave a comment