Functions of Nervous Tissue

Functions of Nervous Tissue

Overview

• Examination of how parts of the nervous system work together.

• Importance of understanding nervous system anatomy to visualize function.

• Key components in the nervous system including sensory pathways and action potentials.

Sensory Pathway and Motor Command

1. Sensory Pathway to Cerebral Cortex

   • Sensory axons from skin enter spinal cord.

   • Synapse occurs with interneurons in spinal cord.

   • Signal progresses to thalamus and eventually to cerebral cortex for conscious perception.

2. Action Potential Process

   • Sensory neurons activated by stimuli (e.g., water temperature).

   • Graded potentials initiate action potentials if the stimulus is strong enough.

3. Neurons Involved

   • Upper Motor Neuron: Sends commands from the cerebral cortex.

   • Lower Motor Neuron: Receives command and leads to muscle contractions via neuromuscular junctions.

Detailed Example: Showering

• 1. Activation of Thermoreceptors

  • Thermoreceptors detect temperature changes; critical for response to environmental stimuli.

• 2. Graded Potential

  • Thermoreceptors' response reflects temperature intensity; graded potential varies with stimulus strength.

• 3. Action Potential

  • If graded potential exceeds threshold, action potential triggering occurs:

    • Travels along the axon's length; described as propagation.

• 4. Release of Neurotransmitters

  • Arrival at axon terminals causes neurotransmitter release, critical for next neuronal transmission.

Sensation to Action

• 5. Integration in CNS

  • Sensory data relayed from thalamus to cerebral cortex for processing, integrating sensory info with emotions and memories.

  • Decision-making based on integrated information (e.g., adjusting water temperature or exiting shower).

Motor Response Execution

• 6. Muscle Movement Command

  • Precentral gyrus of frontal cortex initiates motor commands.

  • Upper motor neurons with long axons synapse with lower motor neurons in spinal cord to convey signals for muscle contraction.

Neuromuscular Junction and Muscle Contraction

• 7. Lower Motor Neuron Function

  • Action potentials in lower motor neurons lead to the release of acetylcholine at the neuromuscular junction.

  • Triggers muscle fiber action potentials resulting in muscle contractions; a process completed rapidly.

Everyday Connection: Neurophysiology Career Path

• Educational Journey:

  • A Bachelor's degree in relevant fields (biology, psychology, etc.) is essential.

  • Graduate programs for deeper specialization focus on research; typically five years.

• Opportunities Available:

  • Academic positions, research scientist roles, and medical degrees leading to clinical applications.

  • Varied career paths within biotechnology and direct work with patients diagnosing/treating disorders.