1 Chapter 2 Overview of the Nervous System. 2 Anatomical Directions Help Us Locate Structures in the Nervous System.

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Chapter 2

Overview of the Nervous System

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Anatomical Directions Help Us Locate Structures in the Nervous System

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Anatomical Directions for a Four-Legged Animal

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In humans, the dorsal parts of our brain form a 90-degree angle with the dorsal parts of the spinal cord.

Anatomical Directions in a Two-legged Animal

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Planes of Section

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Basic Features of the Nervous System

Meninges:

Dura mater:

Arachnoid membrane:

Pia mater:

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Basic Features of the Nervous System

Ventricles: Hollow spaces within the brain. Each ventricle produces cerebrospinal fluid

(CSF). CSF supports the weight of the brain. Prevents pressure on neurons, which would lead

to false info Helps reduce shock to the CNS caused by sudden

head movements.

Choroid plexus: The highly vascular tissue that protrudes into

the ventricles and produces cerebrospinal fluid.

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Circulation of the Cerebrospinal Fluid

Four ventricles:

• 2 lateral ventricles

• 3rd ventricle

• 4th ventricle

Central canal of the spinal cord

Subarachnoid space

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The Brain’s Blood Supply

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In rest of body In brain

Blood-Brain Barrier (barrier #1)

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Blood-Brain Barrier (barrier #2)

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The Organization of the Nervous System

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The Spinal Cord

Functions:

The “information superhighway”

Protective withdrawal reflexes Patellar reflex

Postural reflexes

Divisions of the Brain

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Medulla Cerebellum Pons

Raphe Nuclei Locus Coeruleus

The Three Main Sections of the Brain: The Hindbrain

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Tectum:

Superior Colliculus

Interior Colliculus

Tegmentum:

Periaqueductal Gray

Substantia Nigra

The Three Main Sections of the Brain: The Midbrain

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Thalamus

Hypothalamus

The Three Main Sections of the Brain: The Forebrain - Diencephalon

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• Basal Ganglia

The Three Main Sections of the Brain: The Forebrain - Telencephalon

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The Three Main Sections of the Brain: The Forebrain - Telencephalon

Limbic System:

Hippocampus

Amygdala

Cingulate Cortex

(hypothalamus)

Septum

Olfactory Bulb

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• Cerebral Cortex

The Three Main Sections of the Brain: The Forebrain - Telencephalon

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Connections Between the Hemispheres The corpus callosum The anterior commissure

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The Cerebral Cortex II

Lobes: Frontal Parietal Occipital Temporal

Functions: Sensory Motor Association

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The Peripheral Nervous System

Autonomic nervous system: Controls the body’s vegetative functions. “fight or flight” response

Sympathetic division: Controls functions that accompany arousal and expenditure

of energy. Parasympathetic division:

Controls functions that occur during a relaxed state.

Somatic nervous system: Controls the movement of skeletal muscles or

transmits somatosensory information to the central nervous system.

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Autonomic Nervous System

• Sympathetic

•Parasympathetic

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Somatic Nervous System

The Cranial Nerves Twelve pairs of cranial nerves exit the brain. Provide sensory and motor functions to the

head and neck.

The Spinal Nerves 31 pairs exit the spinal cord Provide sensory and motor functions to the

torso, arms, and legs

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Cranial Nerves