The two functional divisions of the Peripheral Nervous System (PNS) are the sensory (afferent) division and the motor (efferent) division.
Breakdown of the Functional Divisions
Here's a more detailed look at each division:
| Division | Function | Direction of Information Flow | Examples |
|---|---|---|---|
| Sensory (Afferent) | Transmits nerve impulses from sensory receptors in the body to the central nervous system (CNS). | Towards the CNS | Feeling the heat of a stove, tasting food, smelling a flower. |
| Motor (Efferent) | Transmits nerve impulses from the CNS to muscles and glands, causing them to respond. | Away from the CNS | Moving your hand away from the hot stove, salivating when you smell food, your heart beating. |
Sensory Division (Afferent)
- This division is responsible for detecting changes in the internal and external environment.
- Sensory receptors located throughout the body send signals to the brain and spinal cord.
- These signals provide the CNS with information necessary for generating appropriate responses.
- Examples include:
- Somatic sensory: Detecting touch, pain, temperature, and proprioception (body position).
- Visceral sensory: Monitoring internal organ conditions like blood pressure and pH levels.
Motor Division (Efferent)
- This division carries commands from the CNS to effector organs (muscles and glands).
- These commands result in muscular contractions or glandular secretions.
- The motor division is further divided into:
- Somatic Nervous System: Controls voluntary movements of skeletal muscles.
- Autonomic Nervous System: Controls involuntary functions like heart rate, digestion, and breathing.
Key Takeaway
The PNS acts as a communication network between the body and the central nervous system (brain and spinal cord). The sensory division brings information to the CNS, while the motor division sends instructions from the CNS to the body. These two divisions work together to enable all bodily functions and interactions with the environment.
