AP1.2.A and AP1.3.A (Mod 10, Stax 3.3 and 3.5)

Central Nervous System (CNS)

  • Definition: The CNS is a complex network that coordinates the activities of the body and processes sensory information. It is primarily composed of the brain and spinal cord, responsible for thought processing, memory, and decision-making.

  • Function: Regulates bodily functions, interprets sensory information, and facilitates communication between different parts of the body.

Peripheral Nervous System (PNS)

  • Definition: The PNS connects the CNS to the limbs and organs. It includes all neural pathways outside of the brain and spinal cord.

  • Components: Divided into two main parts: the somatic nervous system and the autonomic nervous system.

Somatic Nervous System

  • Definition: Controls voluntary movements by transmitting motor commands from the CNS to the muscles.

  • Function: Relays sensory information to the CNS from external stimuli, enabling conscious control over skeletal muscles.

Autonomic Nervous System

  • Definition: Regulates involuntary bodily functions, such as heartbeat, digestion, and respiratory rate.

  • Divisions: Further divided into the sympathetic and parasympathetic systems, which work generally in opposition to maintain homeostasis.

Sympathetic Nervous System

  • Function: Prepares the body for 'fight or flight' responses during stressful situations. Increases heart rate and dilates airways.

  • Role: Activates energy expenditure and alerts the body to react to perceived threats.

Parasympathetic Nervous System

  • Function: Promotes 'rest and digest' activities, conserving energy and relaxing the body after stress. Slows heart rate and enhances digestion.

  • Role: Restores the body to a state of calm.

Reflex Arc

  • Definition: A neural pathway that controls a reflex action. Involves sensory neurons, interneurons, and motor neurons.

  • Function: Allows for rapid responses to stimuli without the need for conscious thought.

Homeostasis

  • Definition: The ability of the body to maintain stable internal conditions, despite external changes.

  • Importance: Essential for optimal functioning of biological systems; involves feedback loops.

Sensory Neuron

  • Definition: Transmit sensory information from receptors to the CNS for processing.

  • Function: Responsible for converting environmental stimuli into electrical impulses.

Examples related to the nervous system include:

  • CNS Examples: Interpretation of sensory information like heat from a stove, decision-making when solving a math problem, and the coordination of muscle movements while playing a sport.

  • PNS Examples: The sensation felt in the hand when touching something hot (via sensory neurons) and the response of pulling the hand back (via motor neurons).

  • Somatic Nervous System Examples: Voluntary actions such as writing or walking.

  • Autonomic Nervous System Examples: Heart rate increasing during exercise (sympathetic) and digestion occurring while resting (parasympathetic).

  • Reflex Arc Example: Quickly pulling your hand back when touching a hot object without consciously thinking about it.