205 AUTONOMIC NERVOUS SYSTEM (ANS)
- Nervous system
- Central nervous system (integrative functions)
- → brain
- → spinal cord.
- Peripheral nervous system
- Sensory functions
- Cranial & spinal nerves are peripheral.
- Motor functions
- Somatic nervous system (skeletal muscle effectors)
- Autonomic nervous system (smooth muscle, cardiac muscle, and gland effectors)
- Enteric Nervous System.
- Sympathetic (fight or flight)
- Parasympathetic (rest and digest)
2 divisions that serve the same organs but they create opposite effects in them, to either excite (them) or subdue them. (excite – sympathetic; subdue – parasympathetic)
- Efferent N.S. to Skeletal muscles (Somatic)
- ↳ Signals from the CNS to skeletal muscles travel through 1 neuron.
- Efferent NS to visceral effectors (Autonomic)
- ↳ Signals from the CNS to visceral effectors requires two neurons
- ↳ Pre-synaptic
- ↳ Post-synaptic
- Sympathetic
- Parasympathetic
205 cont.
The autonomic Reflex arc:
Can exhibit both polysynaptic & monosynaptic
- ↳ Allows for the regulation of autonomic functions without involving conscious control or higher brain centers. Instead it relais on a neural pathway that primarily involves the spinal cord, brainstem, and autonomic ganglia.
- ↳ The difference btw. ARA & spinal RA is that, ARA regulate autonomic functions.
→ Compartments.
- Autonomic Receptors: Detect changes in the internal environment of the body.
- Sensory Neuron: Carry input from the receptor to the CNS.
- Integration Center; Process the sensory input.
- ↳ This center can be a spinal cord segment or a brainstem nucleus.
- Preganglionic neuron:
- ↳ Emerge from the lateral horn in the spinal cord or cranial nucleus neurons in the brainstem
- Autonomic ganglion
- Postganglionic fiber: project from the ganglion to the target effector.