Nervous system

3 systems interact to produce responses:

• 1. Immune system - Protects body from infection, fights viruses, bacteria and foreign
• 2. Endocrine system - Maintains internal state, controls growth, development/reproduction
• 3. Nervous system - Controls activity coordinating rapid responses, biological basis of cognition

How is behaviour generated? a. Info from environment registered.  b. Info processed   c. Appropriate response generated

Behaviour = Internally coordinated responses of organisms to internal/external environment. Plants have no NS, sponges are only multicellular animal without one. Simplest NS = uncentralised e.g. sea star, hydra. Centralised NS = leech, insects, flatworm.

• Psychobiology = Relationship between behavour + biological processes
• Pragmatic = Experimental study of human behaviour
• Dualism = Mind and matter are separate
• Nervous system = Electrochemically active cells, specialised to communicate

• Centralised NS -> Cell bodies cluster together in head area. Peripheral -> Not clustered
• Neurons have... a. Cell body   b. Dendrites   c. Axon   d. Axon terminals
• Vertebrates NS: Are more complex, central & peripheral are more separated, hierarchy

Functions of NS: 1. Control/coordinate behaviour.  2. React quickly.  3. Muscle spindles activate sensory neuron when muscles stretch  4. Axons enter spinal cord via dorsal root - connect motor   5. Motor axons send axons via ventral root, contracts  6. Resist/dampen stretching of skeletal

Signal = Any change in cell

Peripheral NS - split into somatic and autonomic. Autonomic = no external input. Output = involuntary control (muscles, glands) Somatic - input = sense organs. Output = Voluntary control (skeletal) Automatic = sympathetic or parasympathetic

• Learning = modifying links between inputs & responses - plants can't do this as have no NS
• Knee-jerk - monosynaptic -> walking smooth. - Polysynaptic = withdrawal

Without a brain: Monosynaptic reflex arc. Detection, interpretation and motor command-2 neurons

Polysynpatic relfex arc: Sensory/motor neurons connected via interneurons. Sensor & effector in different locations. Spinal cord generates complex movement patterns, but these are involuntary as responses to appropriate stimulation

• Spinal cord = densely packed neurons
• Grey matter = Cell bodies densely packed, protective
• Complex movement patterns produced in spinal cord alone