Equine_nervous_system-2025

Nervous System Overview

• The equine nervous system is the most complex in the body.

• It controls all other equine body systems.

Components of the Nervous System

• Main components include:

  • Brain

  • Spinal cord

  • Spinal nerves

  • Cranial nerves

  • Vagus nerve

  • Network of nerves to forelimb

  • Autonomic nervous system

  • Sciatic nerve

Function of the Nervous System

• Composed of billions of neurons.

• Supplies information about internal and external environments.

• Conveys sensation: impulses travel back and forth between the brain/spinal cord and body parts.

• Acts as the body’s communication system, connecting various functions.

Division of the Nervous System

Central Nervous System (CNS)

• Components:

  • Brain

  • Spinal Cord

• Functions:

  • Controls conscious or voluntary actions.

  • Key structures of the CNS involve the brain which is responsible for numerous tasks:

    • Brain stem:

      • Controls heartbeat, respiration, and body temperature.

    • Cerebrum:

      • Involved in memory, intelligence, and emotional responses.

    • Cerebellum:

      • Manages muscular coordination, balance, and equilibrium

      • Spinal Cord: Reflex Arch (knee-jerk) and connects pns and the brain.

Peripheral Nervous System (PNS)

• Function:

  • Connects CNS to limbs and organs.

  • Extends outside CNS and lacks the protective barriers present in CNS, making it vulnerable to damage.

• Subdivisions:

  • Somatic Nervous System:

    • Coordinates body movements and responses to external stimuli.

    • Involves conscious control.

  • Autonomic Nervous System (ANS):

    • Controls involuntary functions (e.g., circulatory and respiratory systems).

    • Divided into:

      • Sympathetic Nervous System:

        • Activates the ‘Fight or Flight’ response.

        • Prepares the horse for danger or stress by increasing heart rate and blood pressure.

      • Parasympathetic Nervous System:

        • Manages 'Rest and Digest' functions when the horse is relaxed.

        • Promotes digestion and general maintenance of body systems.

Neuronal Communication

• Neurons are the basic functional units:

  • Composed of:

    • Dendrites: Receive signals.

    • Cell Body: Contains the nucleus and organelles.

    • Axon: Sends messages away from the cell body.

• Types of Neurons:

  • Sensory Neurons: Transmit impulses from sense receptors to CNS.

  • Motor Neurons: Send impulses from CNS to muscles or glands.

  • Relay Neurons: Connect sensory and motor neurons.

• Synapse: Connection point between neurons for signal transfer, utilizing neurotransmitters (e.g., acetylcholine).

Reflex Actions

• Reflexes operate independently of the brain; reactions occur instinctively.

• Animals are born with reflexes, allowing immediate responses to stimuli.

Eastern Equine Encephalitis

• A serious mosquito-borne viral disease affecting the central nervous system.

• Symptoms range from mild (fever, headache) to severe (seizures, coma, brain damage, death).

• No specific treatment is available, emphasizing the importance of preventive measures.

Relationship Between Sensory, Motor, and Relay Neurons

• Nerve cells do not touch; there is a microscopic space between them called a synapse.

• An impulse in the neuron before the synapse (sensory neuron) stimulates the production of chemicals called neurotransmitters (e.g., acetylcholine) into the synaptic gap.

• Neurotransmitters diffuse across the gap.

• Upon reaching the membrane of the next nerve cell (relay neuron), they stimulate a nervous impulse, facilitating communication between the sensory neuron and motor neuron through the relay neuron.