Chapter Two
Functional Neuroanatomy and the
Evolution of the Nervous System
© Cengage Learning 2016
© Cengage Learning 2016
Anatomical Directions
• Rostral or anterior
– Head end of four legged animal
• Caudal or posterior
– Tail end of four legged animal
• Inferior or ventral
– Towards the belly
• Superior or dorsal
– Towards the back
© Cengage Learning 2016
Anatomical Directions (cont’d.)
© Cengage Learning 2016
Planes of Section
• Sagittal
– Parallel to midline
• Coronal
– Divides nervous system front to back
• Horizontal
– (axial, transverse)
– Divides brain from top to bottom
© Cengage Learning 2016
Planes of Section (cont’d.)
© Cengage Learning 2016
Protecting and Supplying the Nervous
System
• Meninges
– Three layers of meninges provide protection
• Cerebrospinal fluid
– Secreted in hollow spaces in the brain known
as ventricles
– Circulates through ventricles, subarachnoid
space, and central canal of the spinal cord
• Blood supply
– Brain receives nutrients through the carotid
arteries and vertebral arteries
© Cengage Learning 2016
The Skull and Three Layers of Membrane
Protect the Brain
© Cengage Learning 2016
Cerebrospinal Fluid Circulation
© Cengage Learning 2016
Hydrocephalus
© Cengage Learning 2016
The Brain Has a Generous Supply of Blood
© Cengage Learning 2016
The Organization of the Nervous System
• The central nervous system
– Brain and spinal cord
• The peripheral nervous system
– All nerves that leave from the brain and spinal
cord and extend to and from all parts of the
body
© Cengage Learning 2016
The Organization of the Nervous System
© Cengage Learning 2016
The Central Nervous System –
The Spinal Cord
• Anatomy
– Extends from the medulla to the first lumbar
vertebra
– 31 spinal nerves (cervical, thoracic, lumbar,
sacral, coccygeal)
– White matter (nerve fibers); gray matter (cell
bodies)
• Reflexes
– Patellar reflex
– Withdrawal reflex
© Cengage Learning 2016
The Anatomy of the Spinal Cord
© Cengage Learning 2016
Embryological Divisions of the Brain
© Cengage Learning 2016
Structures of the Brainstem
© Cengage Learning 2016
Structures of the Brainstem (cont’d.)
© Cengage Learning 2016
The Central Nervous System: The
Hindbrain
• Medulla (myelencephalon)
– Breathing, heart rate, blood pressure
– Reticular formation
• Consciousness, arousal, movement, and pain
• Metencephalon
– Pons: balance, motion sickness
– Cerebellum
• Voluntary movements, muscle tone, balance,
speech, motion sickness, executive functions, and
emotional processing
© Cengage Learning 2016
The Internal Structure of the Midbrain
• Periaqueductal gray
– Natural pain management
• Red nucleus
– Motor output pathway
• Substantia nigra
– Motor output pathway
– Parkinson’s disease
• Superior and inferior colliculi
– Visual and auditory stimuli
© Cengage Learning 2016
The Internal Structure of the Midbrain
© Cengage Learning 2016
Important Structures in the Brainstem
© Cengage Learning 2016
The Central Nervous System –
The Forebrain
• The forebrain is composed of the
diencephalon and the telencephalon
• Diencephalon
– Thalamus
• Receives sensory input
– Hypothalamus
• Regulation of the endocrine system
© Cengage Learning 2016
The Thalamus and Hypothalamus of the
Diencephalon
© Cengage Learning 2016
The Central Nervous System –
The Forebrain (cont’d.)
• Telencephalon
– Basal ganglia
• Motor control
• Parkinson’s and Huntington’s disease; ADHD
– Limbic sstem
• Learning, motivated behavior, and emotion
– Cerebral cortex
• Four lobes
• Sensory cortex, motor cortex, and association
cortex
© Cengage Learning 2016
The Basal Ganglia and the Limbic System
© Cengage Learning 2016
Structures of the Limbic System
© Cengage Learning 2016
The Hippocampus
© Cengage Learning 2016
Comparative Convolutions of the Cortex
© Cengage Learning 2016
The Layers of the Cerebral Cortex
© Cengage Learning 2016
Brodmann’s Map of the Brain
© Cengage Learning 2016
The Lobes of the Cerebral Cortex
© Cengage Learning 2016
The Corpus Callosum and the Anterior
Commissure
© Cengage Learning 2016
Localization of Function in the Cortex
• Frontal lobe
– Primary motor cortex, cognitive processes
– Dorsolateral prefrontal cortex, orbitofrontal
cortex
– Phineas Gage
– Lobotomies
– Broca’s area
– Lateralization of function
© Cengage Learning 2016
The Case of Phineas Gage
© Cengage Learning 2016
Brain Circuits and the Connectome
• The Human Connectome Project
– Mapping the neural connections within the
brain
– Cellular and macro levels of investigation
© Cengage Learning 2016
The Peripheral Nervous System
• The cranial nerves
– Enter and exit the brain directly to serve the
region of the head and neck
• The spinal nerves
– 31 pairs provide sensory and motor pathways
to the torso, arms, and legs
– Mixed nerves (afferent and efferent)
• The autonomic nervous system
– Manages the vital functions of the body
without conscious effort or awareness
© Cengage Learning 2016
The Twelve Pairs of Cranial Nerves
© Cengage Learning 2016
The Structure of the Spinal Cord
© Cengage Learning 2016
The Autonomic Nervous System
• The sympathetic nervous system
– Fight-or-flight system
• The parasympathetic nervous system
– Provides rest, repair, and energy storage
• The enteric nervous system
– Serves the gastrointestinal tract
• The endocrine system
– Hypothalamic control of hormone release
– Pituitary gland
© Cengage Learning 2016
The Sympathetic and Parasympathetic
Nervous Systems
© Cengage Learning 2016
The Evolution of the Human Brain and
Nervous System
• Natural selection and evolution
– Natural selection favors the organism with the
highest degree of fitness
• Evolution of the nervous system
– Fairly recent; vertebrates or chordates are
animals with spinal columns and real brains
• Evolution of the human brain
– Outstanding modern feature is our brain size
– Brain development occurred very recently
© Cengage Learning 2016
Timeline for the Evolution of the Brain
© Cengage Learning 2016
The Evolution of Chordate Brains
© Cengage Learning 2016
Human Brain Development Proceeded
Swiftly
© Cengage Learning 2016