BK

sac 1

Topics Covered:

  • Structure and Function of the Nervous System (CNS and PNS)

  • Conscious and Unconscious Responses - Spinal Reflex

  • Structure and Function of Neurons

  • Neurotransmitters - Glutamate and GABA

  • Effects of Dopamine and Serotonin on Brain Activity

  • Synaptic Plasticity - Long Term Potentiation and Depression

The Nervous System

Key Functions:

  • Receives Sensory Information: Processes sensory data from both internal (e.g., internal organs) and external environments (e.g., sights, sounds, smells).

  • Processes Information: Can occur consciously (thinking) or unconsciously (reflexes).

  • Coordinates Responses to Stimuli: Links sensory input to motor output, allowing organisms to respond effectively to their environments.

Example of Response:

  • Reception: Sensory receptors in the eyes detect light.

  • Processing: The brain interprets the sensory input, recognizing it as a delicious cake.

  • Coordination: The response involves salivation (preparing for digestion) and actions such as reaching for and picking up the cake.

Central and Peripheral Nervous Systems

CNS Components:

  • Brain: The central control unit that processes information and dictates responses. Divided into various regions (e.g., cerebrum, cerebellum, brainstem), each responsible for different functions, including movement, perception, and autonomic functions.

  • Spinal Cord: Transmits signals between the brain and the rest of the body, also facilitating reflexes independent of brain input.

PNS Functions:

  • Sensory Neurons: Carry information from sensory organs (e.g., eyes, ears, skin) to the CNS for processing.

  • Motor Neurons: Transmit impulses from the CNS to muscles or glands, facilitating voluntary and involuntary actions.

PNS Subdivisions:

  • Somatic Nervous System (SNS): Responsible for voluntary actions and transmits sensory and motor messages. It regulates activities such as walking and writing.

  • Autonomic Nervous System (ANS): Manages involuntary actions such as heartbeat and digestion, allowing the body to function without conscious effort.

Autonomic Nervous System

Divisions:

  • Sympathetic Nervous System: Activates the body's fight or flight response during stressful situations, preparing for immediate action by increasing heart rate, dilating pupils, and diverting blood to essential organs.

  • Parasympathetic Nervous System: Promotes rest and digest activities, calming the body after a stressful experience, facilitating processes like digestion and energy conservation.

Structure and Function of Neurons

Neuron Components:

  • Dendrites: Branch-like structures that receive synaptic signals from other neurons, initiating the neuronal communication process.

  • Axon: A long, slender projection that transmits electrical impulses away from the neuron's cell body to other neurons or muscle cells.

  • Myelin Sheath: A fatty insulating layer around the axon that increases the speed of electrical signal transmission, crucial for efficient communication across the nervous system.

  • Axon Terminals: End points that release neurotransmitters into synapses to communicate with adjacent neurons.

Neurotransmitters

  • Excitatory Neurotransmitter:

    • Glutamate: The primary excitatory neurotransmitter involved in promoting action potentials, essential for synaptic plasticity, learning, and memory formation.

  • Inhibitory Neurotransmitter:

    • GABA (Gamma-Aminobutyric Acid): The main inhibitory neurotransmitter that works to reduce neural activity, aiding in calming the nervous system and is often implicated in anxiety disorders.

Synaptic Plasticity

Definitions:

  • Long Term Potentiation (LTP): The process by which synaptic connections become stronger with repeated activation, believed to be a cellular mechanism underlying learning and memory.

  • Long Term Depression (LTD): The weakening of synaptic transmission due to a decrease in activity, playing a vital role in synaptic pruning and memory adaptation.

Conclusion

Understanding the structures and functions of the nervous system and its components is crucial in explaining how we respond to stimuli and process information. Knowledge of neuronal communications, neurotransmitter actions, and the intricate workings of both the CNS and PNS reveals how behavior, cognition, and bodily functions are interlinked and regulated.

chrinic stress negativley impacts theneural pla