Structure and Function of the Nervous System

Peripheral Nervous System

• Somatic

  • Neurons that bring messages from the senses to the central nervous system and vice versa.

• Autonomic

  • Consists of neuron controling the heart, intestines, breathing, etc.

  • It is split into two:

    • Parasympathetic Branch

      • NT: acetylcholine

      • Increases: salvation, digestive function, bladder concentration

      • Decreases: breathing, heart rate, constricts pupil

    • Sympathetic Branch

      • NT: norephephrine

      • Increases: heart rate, breathing, sweating, dilating pupils

      • Decreases: digestive functions, bladder concentrations

Central Nervous System

• Spinal Cord

  • Takes sensory information from bodies peripheral sensory receptors and relays it to the brai and conducts outgoing motor signals frm the brain to the muscles.

  • Goes from the brainstaim to the cauda equina (horse's tail)

    • Afferent neurons: carry sensory input through the dorsal route into the spinal cord

    • Efferent neurons: carry motor output through the ventral route away from the spinal cord

• Brain 

  • Brain Stem

    • 3 main regions

      • Medulla Oblongata:

        •  Located at the lowest part of the brainstem

        • The medulla oblongata controls essential autonomic functions such as heart rate, blood pressure, breathing, and reflexes like swallowing, vomiting, coughing, and sneezing.

      • Pons: 

        • Situated above the medulla oblongata

        • The pons serves as a bridge connecting different parts of the brain, including the cerebrum and cerebellum. 

        • It plays a role in regulating sleep, breathing, swallowing, facial movements, and some sensory functions.

      • Midbrain (Mesencephalon):

        •  The midbrain is the uppermost region of the brainstem, serving as a relay station for sensory and motor signals traveling between the brain and spinal cord. 

        • It plays a critical role in controlling eye movements, auditory and visual processing, and coordinating involuntary movements.

        • Additionally, it contains nuclei involved in the regulation of sleep-wake cycles, arousal, and temperature control.

  • Cerebellum

    • Body position, balance, posture, walking, coordination and being able to label things.

  • Diencephalon (Thalamus and Hypothalamus)

    • Thalamus

      • Bilateral strucure or one one each side of the hemisphre

      • Connected by massa intermedia

      • Function: involved in almost all sensory information

        • All have synaptic "stop" in the thalamus

        • One sensory function that doesn't seems to work is smell

      • 4 majors nuclei of the thalamus

        • Lateral Geniculate

          • Recess info from the cells of the retina and sends it to the primary visual cortex

        • Medial Geniculate

          • Receives info from inner ear and sees across to auditory cortex

        • Ventral Posterior Nucleus

          • Somatosensory info to the primary somatosensory cortex and it is involved with body positioning and pain.

        • Pulvinar Nucleus

          • Function: attention and integates things from different cortices.

      • Hypothalamus

        • Function: hormal production and control, maintains homeostasis by using endocrine systm which is largely conrolled by the pituitary gland

  • Telencephalon (Cerebrum)

    • It includes:

      • The Limbic System

        • Includes: hypothalamus, hippocampus, anterior thalamic nucleus, amygdale, mammilary body orbital frontal ortex and parts of the basal ganglia

        • Function: supports memory, involved in emotions and motivational states (thirst, hunger and libido), provides integrative functions where it integrate autonomic and hormonal processes with mental activities

      • Basal Ganglia

        • Collection of nuclei deep within in the brain

          • Caudate Nucleus

          • Putamen

          • Globus Pallidus

          • Subthalamic Nucleus

          • Substanstia nigra

        • Involved in: motor preparation, action selection, task switching, reward and goal learning

      • Olfactory Bulb

        • Plays a central role in olfaction

      • Cerebral Cortex

        • Has 4 main lobes

          • Frontal Lobe

          • Parietal Lobe

          • Occipital Lobe

          • Temporal Lobe