BRAINCAKEAutonomic Nervous System
The autonomic nervous system (ANS) is the part of the peripheral nervous system that controls the internal organs automatically, without conscious thought. Its effectors are smooth muscle (for example in the gut, blood vessel walls, bronchioles and iris), cardiac muscle and glands. It controls activities such as heart rate, digestion, breathing rate, sweating and pupil size, so it is central to homeostasis. The ANS is controlled by centres in the hypothalamus and the medulla oblongata.
A key structural difference from the somatic system is that the pathway from the CNS to the effector uses two motor neurones, which synapse in a ganglion (a cluster of cell bodies) outside the CNS:
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More in Mammalian Nervous System
- Major Areas of the Brain
- Other Areas of the Brain
- Spinal Cord
- Reflex Responses
- Peripheral Nervous System
- Voluntary Nervous System
- Sympathetic Nervous System
- Parasympathetic Nervous System
All 38 lessons in Mammalian Nervous System · All Edexcel A-level Biology topics