NERVOUS SYSTEM Flashcards
1
Q
Function of Nervous System that is responsible for gathering information
it’ sensory receptors monitor changes, called stimuli,
occurring inside and outside the body
A
Sensory Input
2
Q
Function of Nervous System
that processes and interprets sensory input and decides whether action is needed
A
Integration
3
Q
Function of Nervous System that is responsible for a response, or effect, activates muscles or glands
A
Motor output
4
Q
Nervous system classifications are based on:
A
▪ Structures (structural classification)
▪ Activities (functional classification)
5
Q
It consists of
▪ Brain
▪ Spinal cord
Function is
▪ Integration; command center
▪ Interprets incoming sensory information
▪ Issues outgoing instructions
A
Central nervous system (CNS)
6
Q
It’s function is:
▪ Nerves extending from the brain and spinal cord
▪ Spinal nerves—carry impulses to and from the spinal cord
▪ Cranial nerves—carry impulses to and from the brain
Functions
▪ Serve as communication lines among sensory organs, the brain and spinal cord, and glands or muscles
A
Peripheral nervous system (PNS)
7
Q
FUNCTIONAL CLASSIFICATION
▪ Nerve fibers that carry information to the central
nervous system
▪ Somatic sensory (afferent) fibers carry information from the skin, skeletal muscles, and joints
▪ Visceral sensory (afferent) fibers carry information from visceral organs
A
Sensory (afferent) division
8
Q
FUNCTIONAL CLASSIFICATION
▪ Nerve fibers that carry impulses away from the central nervous system organs to effector organs (muscles and glands)
A
Motor (efferent) division
9
Q
Two subdivisions of efferent division
A
•Somatic Nervous System
•Autonomic Nervous System
10
Q
Support cells in the CNS are grouped together as?
A
neuroglia
11
Q
▪General functions of neuroglia
A
▪ Support
▪ Insulate
▪ Protect neurons
12
Q
▪Nervous tissue is made up of two principal cell types
A
▪ Supporting cells (called neuroglia, or glial cells, or glia)
•Resemble neurons
•Unable to conduct nerve impulses
•Never lose the ability to divide
▪ Neurons
13
Q
Type of Supporting Cells that is
▪ Abundant, star-shaped cells
▪ Brace and anchor neurons to blood capillaries
▪ Determine permeability and exchanges between blood
capillaries and neurons
▪ Protect neurons from harmful substances in blood
▪ Control the chemical environment of the brain
A
CNS glial cells: astrocytes
14
Q
Type of Supporting Cell that is :
▪ Spiderlike phagocytes
▪ Monitor health of nearby neurons
▪ Dispose of debris
A
CNS glial cells: microglia
15
Q
Type of Supporting Cell that is :
▪ Line cavities of the brain and spinal cord
▪ Cilia assist with circulation of cerebrospinal fluid
A
CNS glial cells: ependymal cells
16
Q
Type of supporting cell that
▪ Wrap around nerve fibers in the central nervous
system
▪Produce myelin sheaths
A
CNS glial cells: oligodendrocytes
17
Q
Type of Supporting Cell in PNS
That form myelin sheath around nerve fibers in the PNS
A
Schwann cells
18
Q
Type of Supporting Cell in PNS that
▪ Protect and cushion neuron cell bodies
A
Satellite cells
19
Q
What is the function of Neurons and nerve cells?
A
Cells specialized to transmit messages (nerve
impulses)
20
Q
What are the Major regions of all neurons?
A
▪ Cell body—nucleus and metabolic center of the cell
▪ Processes—fibers that extend from the cell body
21
Q
What is the major region neuron that has —nucleus and is metabolic center of the cell
A
Cell body
22
Q
What is the fibers that extend from the cell body
A
Processes
23
Q
What is the Intermediate filaments that maintain cell shape
A
Neurofibrils
24
Q
UNDER Processes (fibers)
What —conduct impulses toward the cell body- Neurons may have hundreds of this
A
Dendrites
25
UNDER PROCESSES conduct impulses away from the cell body
▪ Neurons have only one of this arising from the cell body
at the axon hillock
▪ End in terminals, which contain vesicles with neurotransmitters
▪ terminals are separated from the next neuron by a gap
Axon
26
What is the gap between axon terminals and the
next neuron
Synaptic cleft
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What is the functional junction between nerves where a nerve impulse is transmitted
Synapse
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NEURON THAT IS
▪ White, fatty material covering axons
▪ Protects and insulates fibers
▪ Speeds nerve impulse transmission
Myelin
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▪Myelin sheaths
▪ Schwann cells—wrap axons in a jelly roll–like fashion
(PNS) to form the myelin sheath
▪ Neurilemma—part of the Schwann cell external to the myelin sheath
▪ Nodes of Ranvier—gaps in myelin sheath along the axon
▪ Oligodendrocytes—produce myelin sheaths around axons of the CNS
▪ Lack a neurilemma
▪Myelin sheaths
▪ Schwann cells—wrap axons in a jelly roll–like fashion
(PNS) to form the myelin sheath
▪ Neurilemma—part of the Schwann cell external to the myelin sheath
▪ Nodes of Ranvier—gaps in myelin sheath along the axon
▪ Oligodendrocytes—produce myelin sheaths around axons of the CNS
▪ Lack a neurilemma
30
Types of sensory receptors.
(a) Free nerve endings (pain and temperature receptors)
(b) Meissner’s corpuscle
(touch receptor)
(c) Lamellar corpuscle (deep
pressure receptor)
(d) Golgi tendon organ (proprioceptor)
(e) Muscle spindle (proprioceptor)
31
FUNCTIONAL CLASSIFICATIONS OF NEURONS ARE
▪ Motor (efferent) neurons
—-Carry impulses from the central nervous system to viscera and/or muscles and glands
▪ Interneurons (association neurons)
—Cell bodies located in the CNS
Connect sensory and motor neurons
32
Structural classification of neurons
•MULTIPOLAR NEURONS — many extensions from the cell body
All motor and interneurons are multipolar
Most common structural type
•BIPOLAR NEURONS — one axon and one dendrite
Located in special sense organs, such as nose and eye
Rare in adults
•UNIPOLAR NEURONS —
—have a short single process leaving
the cell body
Sensory neurons found in PNS ganglia
Conduct impulses both toward and away from the cell body
33
▪Functional properties of neurons the
Ability to respond to a stimulus and convert it to a nerve impulse
Irritability
34
Functional properties of neurons that has the ability to transmit the impulse to other neurons,
muscles, or glands
Conductivity
35
Electrical conditions of a resting neuron’s membrane
▪ The plasma membrane at rest is inactive (polarized) ▪ Fewer positive ions are inside the neuron’s plasma
membrane than outside
▪ K+ is the major positive ion inside the cell
▪ Na+ is the major positive ion outside the cell
▪ As long as the inside of the membrane is more negative (fewer positive ions) than the outside, the cell remains inactive
Electrical conditions of a resting neuron’s membrane
▪ The plasma membrane at rest is inactive (polarized) ▪ Fewer positive ions are inside the neuron’s plasma
membrane than outside
▪ K+ is the major positive ion inside the cell
▪ Na+ is the major positive ion outside the cell
▪ As long as the inside of the membrane is more negative (fewer positive ions) than the outside, the cell remains inactive
36
▪ A stimulus changes the permeability of the neuron’s
membrane to sodium ions
▪ Sodium channels now open, and sodium (Na+) diffuses into the neuron
▪ The inward rush of sodium ions changes the polarity at that site and is called depolarization
Action potential initiation and generation
37
In the resting state, the external face of the membrane is slightly positive; its internal face is slightly negative. The chief extracellular ion is sodium (Na+), whereas the chief intracellular ion is potassium (K+). The membrane is relatively impermeable to both ions.
Resting membrane is polarized
38
A stimulus changes the permeability of a local “patch” of the membrane, and sodium ions diffuse rapidly into the cell. This changes the polarity of the membrane (the inside becomes more positive; the outside becomes more negative) at that site
2 Stimulus initiates local depolarization.
39
If the stimulus is strong enough, depolarization causes membrane polarity to be completely reversed, and an action potential is initiated
3 Depolarization and generation of an action potential.
40
Depolarization of the first membrane patch causes permeability changes in the adjacent membrane, and the events described in step 2 are repeated. Thus, the action potential propagates rapidly along the entire length of the membrane.
4 Propagation of the action potential.
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▪ Membrane permeability changes again—becoming impermeable to sodium ions and permeable to potassium ions
▪ Potassium ions rapidly diffuse out of the neuron, repolarizing the membrane
▪ Repolarization involves restoring the inside of the membrane to a negative charge and the outer surface to a positive charge
Repolarization
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. Potassium ions diffuse out of the cell as the membrane permeability changes again, restoring the negative charge on the inside of the membrane and the positive charge on the outside surface. Repolarization occurs in the same direction as depolarization
5 Repolarization
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- are rapid, predictable, and involuntary responses to stimuli
- occur over neural pathways called reflex arcs
Reflexes
44
▪Two types of reflexes
▪ Somatic reflexes
▪ Autonomic reflexes
45
Type pf Reflexes that stimulate the skeletal muscles
▪ Involuntary, although skeletal muscle is normally under voluntary control
▪ Example: pulling your hand away from a hot object
Somatic reflexes
46
Type of reflexes that Regulate the activity of smooth muscles, the heart, and glands
▪ Example: regulation of smooth muscles, heart and blood pressure, glands, digestive system
Autonomic reflexes
47
Five elements of a reflex arc
1. Sensoryreceptor—reactstoastimulus
2. Sensory neuron—carries message to the integration center
3. Integration center (CNS)—processes information and directs motor output
4. Motor neuron—carries message to an effector
5. Effector organ—is the muscle or gland to be
stimulated
Five elements of a reflex arc
1. Sensoryreceptor—reactstoastimulus
2. Sensory neuron—carries message to the integration center
3. Integration center (CNS)—processes information and directs motor output
4. Motor neuron—carries message to an effector
5. Effector organ—is the muscle or gland to be
stimulated
48
TheSimplest type reflex arcs
▪ Example: patellar (knee-jerk) reflex
Two-neuron reflex arcs
49
Type of reflex arcs that
▪ Consists of five elements: receptor, sensory neuron,
interneuron, motor neuron, and effector ▪Example: flexor (withdrawal) reflex
Three-neuron reflex arcs
50
What are the Brain regions
▪ Cerebral hemispheres
▪ Diencephalon
▪ Brain stem
▪ Cerebellum
51
Part or the brain that are paired (left and right) superior parts of the brain
▪ Include more than half of the brain mass
▪ The surface is made of ridges (gyri) and grooves
(sulci)
▪ Fissures are deeper grooves
▪ Lobes are named for the cranial bones that lie over them
▪Cerebral hemispheres
52
What are the
Three main regions of cerebral hemisphere
1. Cortex is superficial graymatter
2. Whitematter
3. Basal nuclei are deep pockets of gray matter
53
PART OF THE BRAIN THAT IS
▪ Primary somatic sensory area
▪ Located in parietal lobe posterior to central sulcus
▪ Receives impulses from the body’s sensory receptors
▪ Pain, temperature, light touch (except for special senses)
▪ Sensory homunculus is a spatial map
▪ Left side of the primary somatic sensory area receives
impulses from right side (and vice versa)
Cerebral cortex - region: cerebral hemisphere
54
Cerebral areas involved in special senses
▪ Visual area (occipital lobe)
▪ Auditory area (temporal lobe)
▪ Olfactory area (temporal lobe)
55
▪Cerebral cortex (continued)
▪ Broca’s area (motor speech area) ▪ Involved in our ability to speak
▪ Usually in left hemisphere
▪ Other specialized areas
▪ Anterior association area (frontal lobe)
▪ Posterior association area (posterior cortex)
▪Cerebral cortex (continued)
▪ Broca’s area (motor speech area) ▪ Involved in our ability to speak
▪ Usually in left hemisphere
▪ Other specialized areas
▪ Anterior association area (frontal lobe)
▪ Posterior association area (posterior cortex)
56
PART OF THE BRAIN THAT
▪ “Islands” of gray matter buried deep within the white
matter of the cerebrum
▪ Regulate voluntary motor activities by modifying instructions sent to skeletal muscles by the primary motor cortex
Basal nuclei — region : cerebral hemisphere
57
WHAT REGION
▪ Sits on top of the brain stem
▪ Enclosed by the cerebral hemispheres
▪ Made of three structures
1. Thalamus
2. Hypothalamus
3. Epithalamus
Diencephalon
58
PART OF THE BRAIN
▪ Encloses the third ventricle
▪ Relay station for sensory impulses passing upward to the cerebral cortex
▪ Transfers impulses to the correct part of the cortex for localization and interpretation
▪Diencephalon: thalamus
59
▪ Makes up the floor of the diencephalon
▪ Important autonomic nervous system center
▪ Regulates body temperature
▪ Regulates water balance
▪ Regulates metabolism
▪ Houses the limbic center for emotions
▪ Regulates the nearby pituitary gland
▪ Houses mammillary bodies for olfaction (smell)
Diencephalon: hypothalamus
60
▪ Forms the roof of the third ventricle
▪ Houses the pineal body (an endocrine gland)
▪ Includes the choroid plexus—forms cerebrospinal fluid
Diencephalon: epithalamus
61
▪ Attaches to the spinal cord ▪ Parts are:
1. Midbrain
2. Pons
3. Medulla oblongata
Brain stem
62
▪ Extends from the mammillary bodies to the pons
inferiorly
▪ Cerebral aqueduct (tiny canal) connects the third and fourth ventricles
▪ Two bulging fiber tracts, cerebral peduncles, convey ascending and descending impulses
▪ Four rounded protrusions, corpora quadrigemina, are visual and auditory reflex centers
Brain stem: midbrain
63
▪ The rounded structure protruding just below the
midbrain
▪ Mostly composed of fiber tracts
▪ Includes nuclei involved in the control of breathing
Brain stem: pons
64
▪ The most inferior part of the brain stem that merges
into the spinal cord
▪ Includes important fiber tracts
▪ Contains important centers that control:
▪ Heart rate
▪ Blood pressure ▪ Breathing
▪ Swallowing
▪ Vomiting
▪ Fourth ventricle lies posterior to pons and medulla
Brain stem: medulla oblongata
65
▪ Diffuse mass of gray matter along the brain stem
▪ Involved in motor control of visceral organs
▪ Reticular activating system (RAS)
▪ Plays a role in awake/sleep cycles and consciousness ▪ Filter for incoming sensory information
Brain stem: reticular formation
66
▪ Two hemispheres with convoluted surfaces
▪ Outer cortex of gray matter and inner region of white matter
▪ Controls balance
▪ Provides precise timing for skeletal muscle activity and
coordination of body movements
Cerebrum
67
Protection of the Central Nervous System
▪ Meninges
▪Cerebrospinal fluid (CSF)
▪Blood-brain barrier
68
▪ Dura mater
▪ Outermost leathery layer
▪ Double-layered external covering
▪ Periosteum—attached to inner surface of the skull
▪ Meningeal layer—outer covering of the brain
▪ Folds inward in several areas ▪ Falx cerebri
▪ Tentorium cerebelli
Meninges
69
Protection of the Central Nervous System
▪ Similar to blood plasma in composition
▪ Formed continually by the choroid plexuses
▪ Choroid plexuses—capillaries in the ventricles of the brain
▪ CSF forms a watery cushion to protect the brain and spinal cord
▪ Circulated in the arachnoid space, ventricles, and central canal of the spinal cord
Cerebrospinal fluid
70
PROTECTIO OF CNS
1. CSF is produced by the choroid plexus of each
ventricle
2. CSF flows through the ventricles and into the subarachnoid space via the median and lateral apertures. Some CSF flows through the central canal of the spinal cord
3. CSF flows through the subarachnoid space
4. CSF is absorbed into the dural venous sinuses via
the arachnoid villi
Cerebrospinal fluid circulation
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PROTECTION OF CNS
▪ Includes the least permeable capillaries of the body
▪ Allows water, glucose, and amino acids to pass through the capillary walls
▪ Excludes many potentially harmful substances from entering the brain, such as wastes
▪ Useless as a barrier against some substances
Blood-brain barrier
72
Traumatic brain injuries
—Concussion
▪ Slight brain injury
▪ Typically little permanent brain damage occurs
—Contusion
▪ Marked nervous tissue destruction occurs ▪ Coma may occur
Death may occur after head blows due to:
▪ Intracranial hemorrhage
▪ Cerebral edema
73
Brain Dysfunctions
▪ Results when blood circulation to a brain area is
blocked and brain tissue dies
▪ Loss of some functions or death may result
▪ Hemiplegia—one-sided paralysis
▪ Aphasia—damage to speech center in left hemisphere
▪Cerebrovascular accident (CVA), or stroke
74
BRAIN DYSFUNCTION
▪ Temporary brain ischemia (restriction of blood flow) ▪ Numbness, temporary paralysis, impaired speech
Transient ischemic attack (TIA)
75
▪Extends from the foramen magnum of the skull to the first or second lumbar vertebra
▪Cauda equina is a collection of spinal nerves at the inferior end
▪Provides a two-way conduction pathway to and from the brain
▪31 pairs of spinal nerves arise from the spinal cord
Spinal Cord
76
WHAT PART OF SPINAL CORD IS
-Internal gray matter is mostly cell bodies
▪ Dorsal (posterior) horns house interneurons
▪ Receive information from sensory neurons in the dorsal root; cell bodies housed in dorsal root ganglion
▪ Anterior (ventral) horns house motor neurons of the somatic (voluntary) nervous system
▪ Send information out ventral root
▪ Gray matter surrounds the central canal, which is filled
with cerebrospinal fluid
▪Gray matter of the spinal cord and spinal roots
77
WHAT PART OF SPINAL CORD
▪ Composed of myelinated fiber tracts
▪ Three regions: dorsal, lateral, ventral columns
▪ Sensory (afferent) tracts conduct impulses toward
brain
▪ Motor (efferent) tracts carry impulses from brain to skeletal muscles
▪White matter of the spinal cord
78
Structure of a Nerve
▪Nerves are bundles of neurons found outside the CNS
▪Endoneurium is a connective tissue sheath that surrounds each fiber
▪Perineurium wraps groups of fibers bound into a fascicle
▪Epineurium binds groups of fascicles
Structure of a Nerve
▪Nerves are bundles of neurons found outside the CNS
▪Endoneurium is a connective tissue sheath that surrounds each fiber
▪Perineurium wraps groups of fibers bound into a fascicle
▪Epineurium binds groups of fascicles
79
—Structure of a Nerve
▪Mixed nerves
▪ Contain both sensory and motor fiber
—-Sensory (afferent) nerves
▪ Carry impulses toward the CNS
—-Motor (efferent) nerves
▪ Carry impulses away from the CNS
—Structure of a Nerve
▪Mixed nerves
▪ Contain both sensory and motor fiber
—-Sensory (afferent) nerves
▪ Carry impulses toward the CNS
—-Motor (efferent) nerves
▪ Carry impulses away from the CNS
80
Cranial Nerves
▪12 pairs of nerves serve mostly the head and neck
▪Only the pair of vagus nerves extends to thoracic and abdominal cavities
▪Most are mixed nerves, but three are sensory only
1. Optic
2. Olfactory
3. Vestibulocochlear
Cranial Nerves
▪12 pairs of nerves serve mostly the head and neck
▪Only the pair of vagus nerves extends to thoracic and abdominal cavities
▪Most are mixed nerves, but three are sensory only
1. Optic
2. Olfactory
3. Vestibulocochlear
81
Cranial Nerves Mnemonic Device
▪ Oh – Olfactory
▪ Oh – Optic
▪ Oh – Oculomotor
▪ To – Trochlear
▪ Touch – Trigeminal
▪ And – Abducens
▪ Feel – Facial
▪ Very – Vestibulocochlear
▪ Green – Glossopharyngeal
▪ Vegetables – Vagus
▪ A – Accessory
▪ H – Hypoglossal
Cranial Nerves Mnemonic Device
▪ Oh – Olfactory
▪ Oh – Optic
▪ Oh – Oculomotor
▪ To – Trochlear
▪ Touch – Trigeminal
▪ And – Abducens
▪ Feel – Facial
▪ Very – Vestibulocochlear
▪ Green – Glossopharyngeal
▪ Vegetables – Vagus
▪ A – Accessory
▪ H – Hypoglossal
82
HAS
▪31 pairs
▪ Formed by the combination of the ventral and dorsal roots of the spinal cord
▪ Named for the region of the spinal cord from which they arise
HAS
▪31 pairs
▪ Formed by the combination of the ventral and dorsal roots of the spinal cord
▪ Named for the region of the spinal cord from which they arise
83
▪Spinal nerves divide soon after leaving the spinal cord into a dorsal ramus and a ventral ramus
▪ Ramus—branch of a spinal nerve; contains both motor and sensory fibers
▪ Dorsal rami—serve the skin and muscles of the posterior trunk
▪ Ventral rami (T1–T12) —form the intercostal nerves that supply muscles and skin of the ribs and trunk
▪ Ventral rami (except T1–T12)—form a complex of networks (plexus) for the anterior
▪Spinal nerves divide soon after leaving the spinal cord into a dorsal ramus and a ventral ramus
▪ Ramus—branch of a spinal nerve; contains both motor and sensory fibers
▪ Dorsal rami—serve the skin and muscles of the posterior trunk
▪ Ventral rami (T1–T12) —form the intercostal nerves that supply muscles and skin of the ribs and trunk
▪ Ventral rami (except T1–T12)—form a complex of networks (plexus) for the anterior
84
▪Plexus—networks of nerves serving motor and sensory needs of the limbs
▪Form from ventral rami of spinal nerves in the cervical, lumbar, and sacral regions
▪Four plexuses
1. Cervical
2. Brachial
3. Lumbar
4. Sacral
▪Plexus—networks of nerves serving motor and sensory needs of the limbs
▪Form from ventral rami of spinal nerves in the cervical, lumbar, and sacral regions
▪Four plexuses
1. Cervical
2. Brachial
3. Lumbar
4. Sacral
85
▪Parasympathetic division is also known as the craniosacral division
▪Preganglionic neurons originate in:
- Cranial nerves III, VII, IX, and X
- S2 through S4 regions of the spinal cord
▪Preganglionic neurons synapse with terminal ganglia; from there, postganglionic axons extend to organs that are served
▪Parasympathetic division is also known as the craniosacral division
▪Preganglionic neurons originate in:
- Cranial nerves III, VII, IX, and X
- S2 through S4 regions of the spinal cord
▪Preganglionic neurons synapse with terminal ganglia; from there, postganglionic axons extend to organs that are served
86
Anatomy of the Sympathetic Division
▪Sympathetic division is also known as the thoracolumbar division
▪Preganglionic neurons originate from T1 through L2
▪ Axons pass through a ramus communicans to enter a sympathetic trunk ganglion
▪ Sympathetic trunk, or chain, lies near the spinal cord
Anatomy of the Sympathetic Division
▪Sympathetic division is also known as the thoracolumbar division
▪Preganglionic neurons originate from T1 through L2
▪ Axons pass through a ramus communicans to enter a sympathetic trunk ganglion
▪ Sympathetic trunk, or chain, lies near the spinal cord
87
Anatomy of the Sympathetic Division
▪After synapsing at the ganglion, the axon may synapse with a second neuron at the same or different level
▪Or, the preganglionic neuron may pass through the ganglion without synapsing and form part of the splanchnic nerves
- Splanchnic nerves travel to the collateral ganglion
- Collateral ganglia serve the abdominal and pelvic
organs
Anatomy of the Sympathetic Division
▪After synapsing at the ganglion, the axon may synapse with a second neuron at the same or different level
▪Or, the preganglionic neuron may pass through the ganglion without synapsing and form part of the splanchnic nerves
- Splanchnic nerves travel to the collateral ganglion
- Collateral ganglia serve the abdominal and pelvic
organs
88
▪When body divisions serve the same organ, they cause antagonistic effects due to different neurotransmitters
▪ Parasympathetic (cholinergic) fibers release acetylcholine
▪ Sympathetic postganglionic (adrenergic) fibers release norepinephrine
▪ Preganglionic axons of both divisions release acetycholine
▪When body divisions serve the same organ, they cause antagonistic effects due to different neurotransmitters
▪ Parasympathetic (cholinergic) fibers release acetylcholine
▪ Sympathetic postganglionic (adrenergic) fibers release norepinephrine
▪ Preganglionic axons of both divisions release acetycholine
89
TYPE OF DIVISION
▪ Response to unusual stimulus when emotionally or
physically stressed or threatened ▪Takes over to increase activities ▪ Remember as the “E” division
▪ Exercise
▪ Excitement
▪ Emergency
▪ Embarrassment
Sympathetic—“fight or flight” division
90
TYPE OF DIVISION
—“housekeeping” activites
▪ “Rest-and-digest” system
▪Conserves energy
▪ Maintains daily necessary body functions ▪ Remember as the “D” division
▪ Digestion ▪ Defecation ▪ Diuresis
▪ Parasympathetic
91
Developmental Aspects of the Nervous System
▪The nervous system is formed during the first month of embryonic development
▪Any maternal infection can have extremely harmful effects
▪Oxygen deprivation destroys brain cells
▪The hypothalamus is one of the last areas of the
brain to develop
Developmental Aspects of the Nervous System
▪The nervous system is formed during the first month of embryonic development
▪Any maternal infection can have extremely harmful effects
▪Oxygen deprivation destroys brain cells
▪The hypothalamus is one of the last areas of the
brain to develop
92
Severe congenital brain diseases include:
▪ Cerebral palsy
▪ Anencephaly
▪ Hydrocephalus
▪Spina bifida
93
▪Premature babies have trouble regulating body temperature because the hypothalamus is one of the last brain areas to mature prenatally
▪Development of motor control indicates the progressive myelination and maturation of a child’s nervous system
▪Premature babies have trouble regulating body temperature because the hypothalamus is one of the last brain areas to mature prenatally
▪Development of motor control indicates the progressive myelination and maturation of a child’s nervous system
94
▪Brain growth ends in young adulthood. Neurons die throughout life and are not replaced; thus, brain mass declines with age
▪Orthostatic hypotension is low blood pressure due to changes in body position
▪Healthy aged people maintain nearly optimal intellectual function
▪Disease—particularly cardiovascular disease—is the major cause of declining mental function with age
▪ Arteriosclerosis is decreased elasticity of blood vessels
▪Brain growth ends in young adulthood. Neurons die throughout life and are not replaced; thus, brain mass declines with age
▪Orthostatic hypotension is low blood pressure due to changes in body position
▪Healthy aged people maintain nearly optimal intellectual function
▪Disease—particularly cardiovascular disease—is the major cause of declining mental function with age
▪ Arteriosclerosis is decreased elasticity of blood vessels
