UNIT 4 Neurological System
Bottom Line! → INCREASED IntraCranial Pressure = BAD BAD BAD BAD BAD!
ICP goes up Mean Arterial Pressure is going down...
Anatomy and Physiology of the Brain and Spinal Cord
Central Nervous System
● Consists of the Nervous System Division that includes:
● the Brain
● the Spinal Cord
Peripheral Nervous System
● Consists of the Nervous System Division that includes:
● The Nerves that extend to the outlying parts of the body
The brain is divided into 3 major areas: the cerebrum, the brainstem, and the cerebellum.
Cerebrum
● The great longitudinal fissure that separates the cerebrum into the right and left hemispheres
● Sensory perception, willed movements, consciousness and memory are mediated here
● Each hemisphere receives sensory information from the opposite side of the body and controls the
skeletal muscles of the opposite side
● Governs sensory and motor activity
● Governs thought and learning
● Cerebral Cortex consists of -
● Outer gray layer
■ It is divided into four lobes
■ responsible for the conscious activities of the cerebrum
Cerebral Cortex (4 Lobes) KNOW THE LOBES AND FUNCTIONS
● Frontal lobe – EXECUTIVE FUNCTION: concentration, abstract thought, information storage or
memory, and motor function.
● Broca’s area for speech
● Prefrontal lobe controls morals, emotions, affect, judgment, personality, and inhibitions
● Injuries to frontal lobe → behavioral issues
● Parietal Lobe - Interprets pain, touch, temperature, and pressure
● Analyzes sensory information and relays the interpretation of this information to other
cortical areas
● Essential to a person’s awareness of body position in space (proprioception), size and shape
discrimination, and right–left orientation
● Temporal Lobe - Auditory center, Wernicke's area for sensory and speech
● Occipital Lobe - Visual Area.. very back.. When people fall backwards they may see stars…
Basal ganglia
1
, ● Cell bodies in white matter
● Assists the cerebral cortex in producing smooth, voluntary movements
● Ataxia is a problem with the basal ganglia
Diencephalon
● Thalamus
● Sensory relay station from various body areas to the cerebral cortex; also involved with
emotions and alerting and arousal mechanisms
● Relays sensory impulses to the cortex
● Provides a thalamic pain gate: increase pain when open
● When opiate receptor sites are activated they close the pain gates stops the
signal
● Prostaglandin 2 one of the main pain gate prostaglandins - affected by Nsaids
● Part of the reticular activating system
● Hypothalamus - MASTER GLAND
● Regulates body temperature, water balance, sleep-wake cycles, appetite, and sexual
arousal , master gland -regulates water balance and temp… people with head injuries
have problems with water balance (SIADH AND DI)
● Regulates autonomic responses of the sympathetic and parasympathetic nervous
● systems
● Regulates stress response and emotions
● Responsible for the production of hormones secreted by the pituitary gland and
hypothalamus
● APeople with increased ICP have trouble with water balance → diabetes insipidus
Brain Stem
● Midbrain
● Part of the brainstem that contains relays for visual and auditory impulses
● Responsible for motor coordination
● Visual reflex and auditory relay centers
● Pons
● Part of the brainstem that is a conduction pathway between areas of the brain and
body; influences respirations
● Contains respiratory centers → Regulates breathing -- autonomic nerves system
● Medulla Oblongata
● Part of the brainstem that contains cardiac, respiratory, vomiting, and vasomotor centers
● Contains all afferent and efferent tracts
● Efferent motor tracts → away from the brain signals to the muscles
● Afferent sensory tracts → towards the brain; pain, temp touch
● Controls heart rate, respiration, blood vessel diameter, sneezing, swallowing, vomiting,
and coughing
Cerebellum
● Regulates muscle coordination, maintenance of equilibrium and posture
■ Source of balance, makes us stand up right
● Coordinates smooth muscle movement
2
, ● Coordinates posture, equilibrium, and muscle tone
The Spinal Cord
● Carries messages to and from the brain to the rest of the body; also mediates reflexes
■ Arc reflexes: touch hot stove pull away immediately.. Skips the brain
■ Other reflexes: go up spinal cord and back down
● Provides neuron and synapse networks to produce involuntary responses to sensory
stimulation
● Allows for control of the number of pain impulses that pass through the spinal cord on their way
● Extends from the first cervical to the second lumbar vertebra
● Protected by the meninges, cerebrospinal fluid, and adipose, tissue
Horns
■ Inner column of gray matter contains two anterior and two posterior horns
● Posterior horns connect with afferent (sensory) nerve fibers
● Anterior horns contain efferent (motor) nerve fibers
Nerve tracts
● White matter contains the nerve tract
● Ascending tract (sensory pathway)
● Descending tract (motor pathway)
Meninges
● Dura mater is the tough and fibrous membrane covers the outside of the brain
● Arachnoid membrane is the thin, delicate membrane and contains subarachnoid fluid
(resembles spider web)
● Pia mater is the vascular membrane, innermost and extends into every fissure and fold and
vascular
● Subarachnoid space is formed by the arachnoid membrane and the pia mater
Cerebrospinal fluid
● Secreted in the ventricles (at the center) and circulates through the ventricles to the
subarachnoid layer of the meninges where it is reabsorbed
● Circulates in the subarachnoid space
■ Normal pressure is 60 to 180 mmH2O
■ Normal volume is 125 to 150ml
● Acts as a protective cushion for brain and spinal cord
● Aids in the exchange of nutrients and wastes throughout brain and spinal cord
● Bad when there is not enough or too much (hydrocephalus (water on the brain) → VP shunt)
Ventricles
● Four ventricles
● Communicate between the subarachnoid space
● Produce and circulate cerebrospinal fluid
Blood Supply
3
, ● Right and left internal carotids
● Right and left vertebral arteries
● These arteries supply the brain via an anastomosis at the base of the brain called the circle of
Willis
● In there is an aneurysm if will usually happen in the circle of Willis
Neurotransmitters → no questions about these
● Acetylcholine
● Norepinephrine
● Dopamine
● Serotonin
● Amino acids
● Polypeptides
Neurotransmitter Release ….or this
● Preganglionic Axons of the Parasympathetic Nervous System -
● release the neurotransmitter
● Acetylcholine
● Postganglionic Axons of the Parasympathetic Nervous System -
● release the neurotransmitter
● Acetylcholine
Neurotransmitter Release…. or this
● Preganglionic Axons of the Sympathetic Nervous System -
● release the neurotransmitter
● Acetylcholine
● Postganglionic Axons of the Sympathetic Nervous System -
● release the neurotransmitter
● Norepinephrine
Autonomic Nervous System
● Consists of Nerves (motor neurons) that conduct Impulses to
● Cardiac Muscle
● Smooth Muscle
● Glandular epithelial tissue
● Regulates involuntary functions
● Consists of the Parasympathetic and Sympathetic Nervous System … KNOW WHAT THE RESPONSES
ARE...
● Sympathetic (adrenergic) fibers dilate pupils, increase heart rate and rhythm, contract blood
vessels, and relax smooth muscles of the bronchi increase glycogenesis in the liver, shuts
down GI tract,
■ Fight or Flight (sympathetic)
● Parasympathetic (cholinergic) fibers produce the opposite effect of sympathetic
■ Peace (parasympathetic)
4
Bottom Line! → INCREASED IntraCranial Pressure = BAD BAD BAD BAD BAD!
ICP goes up Mean Arterial Pressure is going down...
Anatomy and Physiology of the Brain and Spinal Cord
Central Nervous System
● Consists of the Nervous System Division that includes:
● the Brain
● the Spinal Cord
Peripheral Nervous System
● Consists of the Nervous System Division that includes:
● The Nerves that extend to the outlying parts of the body
The brain is divided into 3 major areas: the cerebrum, the brainstem, and the cerebellum.
Cerebrum
● The great longitudinal fissure that separates the cerebrum into the right and left hemispheres
● Sensory perception, willed movements, consciousness and memory are mediated here
● Each hemisphere receives sensory information from the opposite side of the body and controls the
skeletal muscles of the opposite side
● Governs sensory and motor activity
● Governs thought and learning
● Cerebral Cortex consists of -
● Outer gray layer
■ It is divided into four lobes
■ responsible for the conscious activities of the cerebrum
Cerebral Cortex (4 Lobes) KNOW THE LOBES AND FUNCTIONS
● Frontal lobe – EXECUTIVE FUNCTION: concentration, abstract thought, information storage or
memory, and motor function.
● Broca’s area for speech
● Prefrontal lobe controls morals, emotions, affect, judgment, personality, and inhibitions
● Injuries to frontal lobe → behavioral issues
● Parietal Lobe - Interprets pain, touch, temperature, and pressure
● Analyzes sensory information and relays the interpretation of this information to other
cortical areas
● Essential to a person’s awareness of body position in space (proprioception), size and shape
discrimination, and right–left orientation
● Temporal Lobe - Auditory center, Wernicke's area for sensory and speech
● Occipital Lobe - Visual Area.. very back.. When people fall backwards they may see stars…
Basal ganglia
1
, ● Cell bodies in white matter
● Assists the cerebral cortex in producing smooth, voluntary movements
● Ataxia is a problem with the basal ganglia
Diencephalon
● Thalamus
● Sensory relay station from various body areas to the cerebral cortex; also involved with
emotions and alerting and arousal mechanisms
● Relays sensory impulses to the cortex
● Provides a thalamic pain gate: increase pain when open
● When opiate receptor sites are activated they close the pain gates stops the
signal
● Prostaglandin 2 one of the main pain gate prostaglandins - affected by Nsaids
● Part of the reticular activating system
● Hypothalamus - MASTER GLAND
● Regulates body temperature, water balance, sleep-wake cycles, appetite, and sexual
arousal , master gland -regulates water balance and temp… people with head injuries
have problems with water balance (SIADH AND DI)
● Regulates autonomic responses of the sympathetic and parasympathetic nervous
● systems
● Regulates stress response and emotions
● Responsible for the production of hormones secreted by the pituitary gland and
hypothalamus
● APeople with increased ICP have trouble with water balance → diabetes insipidus
Brain Stem
● Midbrain
● Part of the brainstem that contains relays for visual and auditory impulses
● Responsible for motor coordination
● Visual reflex and auditory relay centers
● Pons
● Part of the brainstem that is a conduction pathway between areas of the brain and
body; influences respirations
● Contains respiratory centers → Regulates breathing -- autonomic nerves system
● Medulla Oblongata
● Part of the brainstem that contains cardiac, respiratory, vomiting, and vasomotor centers
● Contains all afferent and efferent tracts
● Efferent motor tracts → away from the brain signals to the muscles
● Afferent sensory tracts → towards the brain; pain, temp touch
● Controls heart rate, respiration, blood vessel diameter, sneezing, swallowing, vomiting,
and coughing
Cerebellum
● Regulates muscle coordination, maintenance of equilibrium and posture
■ Source of balance, makes us stand up right
● Coordinates smooth muscle movement
2
, ● Coordinates posture, equilibrium, and muscle tone
The Spinal Cord
● Carries messages to and from the brain to the rest of the body; also mediates reflexes
■ Arc reflexes: touch hot stove pull away immediately.. Skips the brain
■ Other reflexes: go up spinal cord and back down
● Provides neuron and synapse networks to produce involuntary responses to sensory
stimulation
● Allows for control of the number of pain impulses that pass through the spinal cord on their way
● Extends from the first cervical to the second lumbar vertebra
● Protected by the meninges, cerebrospinal fluid, and adipose, tissue
Horns
■ Inner column of gray matter contains two anterior and two posterior horns
● Posterior horns connect with afferent (sensory) nerve fibers
● Anterior horns contain efferent (motor) nerve fibers
Nerve tracts
● White matter contains the nerve tract
● Ascending tract (sensory pathway)
● Descending tract (motor pathway)
Meninges
● Dura mater is the tough and fibrous membrane covers the outside of the brain
● Arachnoid membrane is the thin, delicate membrane and contains subarachnoid fluid
(resembles spider web)
● Pia mater is the vascular membrane, innermost and extends into every fissure and fold and
vascular
● Subarachnoid space is formed by the arachnoid membrane and the pia mater
Cerebrospinal fluid
● Secreted in the ventricles (at the center) and circulates through the ventricles to the
subarachnoid layer of the meninges where it is reabsorbed
● Circulates in the subarachnoid space
■ Normal pressure is 60 to 180 mmH2O
■ Normal volume is 125 to 150ml
● Acts as a protective cushion for brain and spinal cord
● Aids in the exchange of nutrients and wastes throughout brain and spinal cord
● Bad when there is not enough or too much (hydrocephalus (water on the brain) → VP shunt)
Ventricles
● Four ventricles
● Communicate between the subarachnoid space
● Produce and circulate cerebrospinal fluid
Blood Supply
3
, ● Right and left internal carotids
● Right and left vertebral arteries
● These arteries supply the brain via an anastomosis at the base of the brain called the circle of
Willis
● In there is an aneurysm if will usually happen in the circle of Willis
Neurotransmitters → no questions about these
● Acetylcholine
● Norepinephrine
● Dopamine
● Serotonin
● Amino acids
● Polypeptides
Neurotransmitter Release ….or this
● Preganglionic Axons of the Parasympathetic Nervous System -
● release the neurotransmitter
● Acetylcholine
● Postganglionic Axons of the Parasympathetic Nervous System -
● release the neurotransmitter
● Acetylcholine
Neurotransmitter Release…. or this
● Preganglionic Axons of the Sympathetic Nervous System -
● release the neurotransmitter
● Acetylcholine
● Postganglionic Axons of the Sympathetic Nervous System -
● release the neurotransmitter
● Norepinephrine
Autonomic Nervous System
● Consists of Nerves (motor neurons) that conduct Impulses to
● Cardiac Muscle
● Smooth Muscle
● Glandular epithelial tissue
● Regulates involuntary functions
● Consists of the Parasympathetic and Sympathetic Nervous System … KNOW WHAT THE RESPONSES
ARE...
● Sympathetic (adrenergic) fibers dilate pupils, increase heart rate and rhythm, contract blood
vessels, and relax smooth muscles of the bronchi increase glycogenesis in the liver, shuts
down GI tract,
■ Fight or Flight (sympathetic)
● Parasympathetic (cholinergic) fibers produce the opposite effect of sympathetic
■ Peace (parasympathetic)
4
