THE NERVOUS SYSTEM - All human thoughts, feelings, and actions are seated in and start
with actions of the
nervous system.
Necessary for the PMHNP's role functioning is an understanding of the following basic
neuroanatomy and physiology:
* Neurodeficits that underlie psychiatric disorders
* Actions of and client responses to psychopharmacological treatment agents
The nervous system's primary function is to transfer and exchange information.
The Neuron ("Nerve Cells") - The basic cellular unit of the nervous system
The microprocessor of the brain responsible for conducting impulses from one part of the
body to another
Components of the neuron:
* Cell body: Also known as soma; made up of the nucleus and cytoplasm within cell
membrane
* Stem or axon: Transmits signals away from the neuron's cell body to connect with other
neurons and cells
* Dendrites: Collect incoming signals from other neurons and send the signal toward the
neuron's cell body
Nervous System - Composed of two separate, interconnected divisions:
* Central nervous system (CNS)
** Composed of the spinal cord and the brain
*Peripheral nervous system (PNS)
** Composed of the peripheral nerves that connect the CNS to receptors, muscles, and glands
** Includes the cranial nerves just outside the brain stem
** Comprises the somatic nervous system and the autonomic nervous system:
***Somatic nervous system: Conveys information from the CNS to
skeletal muscles; responsible for voluntary movement
*** Autonomic nervous system: Regulates internal body functions to
maintain homeostasis; conveys information from the CNS to smooth
muscle, cardiac muscle, and glands; responsible for involuntary
movement; divided into the sympathetic nervous system and the
parasympathetic nervous system:
**** Sympathetic nervous system: The excitatory division; prepares the body for stress (fight
or flight); stimulates or increases activity of
organs
**** Parasympathetic nervous system: Maintains or restores energy;
inhibits or decreases activity of organs
,NEUROANATOMY AND THE BRAIN - Brain tissue is categorized as either white matter
or gray matter.
* White matter is the myelinated axons of neurons.
*Gray matter is composed of nerve cell bodies and dendrites; it is the working area of the
brain and contains the synapses, the area of neuronal connection.
Outermost surface of the brain: Structured to contain grooves and dips of corrugated wrinkles
within the brain tissue that provide anatomical landmarks or reference points
* Functions to increase brain's surface area
** Increases working area and cell communication area
* Grooves and dips named by size and depth
** Sulci: Small shallow grooves
** Fissures: Deeper groves extending into the brain
* Gyri are the raised tissue areas.
* Distinct anatomical areas of brain
** The brain is subdivided into the cerebrum and the brainstem.
Cerebrum - Largest part of the brain, which is divided into two halves, the right and left
cerebral hemispheres
* Left hemisphere: Dominant in most people; controls most right-sided body functions
* Right hemisphere: Controls most left-sided body functions
* Normal functioning requires effective coordination of two hemispheres.
* Both hemispheres connected by a large bundle of white matter, the corpus callosum, an
area of sensorimotor information exchange between the two hemispheres
Cerebrum
Frontal lobe: - Frontal lobe: Largest and most developed lobe. Functions include:
* Motor function: Responsible for controlling voluntary motor activity of specific muscles
* Premotor area: Coordinates movement of multiple muscles
* Association cortex: Allows for multimodal sensory input to trigger
memory and lead to decision-making
* Seat of executive functions: Working memory, reasoning, planning,
prioritizing, sequencing behavior, insight, flexibility, judgment, impulse control, behavioral
cueing, intelligence, abstraction
* Language (Broca's area): Expressive speech
* Personality variables: The most focal area for personality development
* Problems in the frontal lobe can lead to personality changes, emotional, and intellectual
changes
Cerebrum
Temporal lobe: - Temporal lobe; functions include:
* Language (Wernicke's area): Receptive speech or language
comprehension
* Primary auditory area
* Memory
* Emotion
* Integration of vision with sensory information
* Problems in the temporal lobe can lead to visual or auditory
hallucinations, aphasia, and amnesia
, Cerebrum
Occipital lobe; - Occipital lobe; functions include:
* Primary visual cortex
* Integration area: Integrates vision with other sensory information
* Problems in the occipital lobe
Cerebrum
Parietal lobe; - Parietal lobe; functions include:
* Primary sensory area
* Taste
* Reading and writing
* Problems in the parietal lobe can lead to sensory-perceptual
disturbances and agnosia
Cerebrum
Cerebrum includes - Cerebrum includes the cerebral cortex, limbic system, thalamus,
hypothalamus, and basal ganglia.
Cerebrum
Cerebral cortex - Cerebral cortex
* Controls wide array of behaviors
* Controls the contralateral (opposite) side of the body: The right hemisphere controls the left
side of the body, and the left hemisphere controls the right side of the body.
* Sensory information is relayed from the thalamus and then processed and integrated in the
cortex.
* Responsible for much of the behavior that makes us human: speech, cognition, judgment,
perception, and motor function
Cerebrum
Limbic system - Limbic system
* Essential system for the regulation and modulation of emotions and memory
* Composed of the hypothalamus, thalamus, hippocampus, and the amygdala
Hypothalamus: Plays key roles in various regulatory functions such as appetite, sensations of
hunger and thirst, water balance, circadian rhythms, body temperature, libido, and hormonal
regulation
Thalamus: Sensory relay station except for smell; modulates flow of sensory information to
prevent overwhelming the cortex; regulates
emotions, memory, and related affective behaviors
Hippocampus: Regulates memory and converts short-term memory into long-term memory
Amygdala: Responsible for mediating mood, fear, emotion, and
aggression; also responsible for connecting sensory smell information with emotions
Cerebrum
Basal ganglia: - Basal ganglia: Also known as the corpus striatum
* Serves as a complex feedback system to modulate and stabilize somatic motor activity
(information conveyed from the CNS to skeletal muscles)