Transcript the central nervous system

FEM 4100
Topic 2
BRAIN ANATOMY
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THE NERVOUS SYSTEM
• Two parts of a nervous system
– Central Nervous System (CNS)
• Brain (in the skull)
• Spinal Cord (in the spine)
– Peripheral Nervous System (PNS)
• Located outside of the skull and spine
• Connects the central nervous system to all other
parts of the body
• Serves to bring information into the CNS and carry
signals out of the CNS
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Central Nervous System
• Spinal cord
– An extension of the brain, reaching from the base of the
brain through the neck and spinal column, that transmits
messages between the brain and the peripheral nervous
system
– Protected by bone and spinal fluid
• Brain structures
– Hindbrain (brainstem)
– Midbrain
– Forebrain
Central Nervous System
• Brainstem
– The structure that begins at the point where the spinal
cord enlarges as it enters the brain
– Medulla
• The part of the brainstem that controls heartbeat, blood
pressure, breathing, coughing, and swallowing
Central Nervous System
• Brainstem (continued)
– Reticular formation
• A structure in the brainstem that plays a crucial role in arousal
and attention and that screens sensory messages entering the
brain
• Pons
• A structure in the brainstem that plays a role in body movement
and even exerts an influence on sleep and dreaming
Central Nervous System
• Cerebellum
– The brain structure that executes smooth, skilled body
movements and regulates muscle tone and posture
Central Nervous System
• Midbrain
– The structures of this brain region act primarily as relay
stations through which the basic physiological functions
of the hindbrain are linked to the cognitive functions of
the forebrain
– Substantia nigra
• The midbrain structure that controls unconscious motor
movements
Central Nervous System
• Thalamus
– The structure, located above the brainstem, that acts as
a relay station for information flowing into or out of the
higher brain centers
– Regulates sleep cycles
• Hypothalamus
– A small but influential brain structure that controls the
pituitary gland and regulates hunger, thirst, sexual
behavior, body temperature, and a wide variety of
emotional behaviors
Central Nervous System
• Limbic system
– A group of structures in the brain, including the
amygdala and hippocampus, that are collectively
involved in emotion, memory, and motivation
– Amygdala
• A structure in the limbic system that plays an important role in
emotion, particularly in response to aversive stimuli
– Hippocampus
• A structure in the limbic system that plays a central role in the
formation of long-term memories
Central Nervous System
THE NERVOUS SYSTEM
Nervous system
Central
nervous system
Spinal cord
Brain
Peripheral
nervous system
Skeletal system
Autonomic
nervous system
Sympathetic
nervous system
Parasympathetic
nervous system
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BASIC FEATURES OF THE NERVOUS SYSTEM
• Neuraxis
– An imaginary line drawn through the center of
the length of the central nervous system, from
the bottom of the spinal cord to the front of the
forebrain.
– Anterior & posterior
• Anterior
– With respect to the central nervous system, located near or
toward the head.
• Posterior
– With respect to the central nervous system, located near or
toward the tail.
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• Rostral & caudal
– Rostral
• “Toward the beak”; with respect to the central nervous system, in a
direction along the neuraxis toward the front of the face.
– Caudal
• “Toward the tail”; with respect to the central nervous system, in a
direction along the neuraxis away from the front of the face.
• Dorsal & ventral
– Dorsal
• “Toward the back”; with respect to the central
nervous system, in a direction perpendicular
to the neuraxis toward the top of the head or the back.
– Ventral
• “Toward the belly”; with respect to the central
nervous system, in a direction perpendicular to
the neuraxis toward the bottom of the skull or the
front surface of the body.
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• Lateral or medial
– Lateral
• Toward the side of the body, away from the middle.
– Medial
• Toward the middle of the body, away from the side.
• Ipsilateral or Contralateral
– Ipsilateral
• Located on the same side of the body.
– Contralateral
• Located on opposites side of the body.
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– Cross section or Frontal section
• A transverse cut like a salami.
• With respect to the central nervous system, a slice taken at
right angles to the neuraxis.
• A slice through the brain parallel to the forehead.
– Horizontal section
• A slice through the brain parallel to the ground.
– Sagittal section
• A slice through the brain parallel to the neuraxis and
perpendicular to the ground.
– Midsagittal
• The plane through the neuraxis perpendicular to the ground;
divides the brain into two symmetrical halves
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MENINGES, VENTRICLES & CSF
• CNS - encased in bone and covered by three
meninges
– Dura mater (“hard mother”)
• The tough outermost membrane of the meninges; flexible,
unstretchable.
– Arachnoid membrane –
• From the Greek arachne, meaning “spider”.
• The weblike middle layer of the meninges, located between the
dura mater and the inner pia mater.
– Pia mater (“pious mother”)
• The layer of the meninges adjacent to the surface of the brain; thin
and delicate.
• Adheres to CNS surface
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MENINGES,Ventricles,
VENTRICLES
CSF
Meninges,
and&CSF
– Subarachnoid space
• The fluid-filled space that cushions the brain; located
between the arachnoid membrane and the pia mater.
– Cerebrospinal fluid (CSF)
• A clear fluid, similar to blood plasma, that fills the
ventricular system of the brain and the subarachnoid
space surrounding the brain and spinal cord.
• Fluid serves as cushion
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The Five Major Divisions of the Brain
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The Five Major Divisions of the
Brain
• Telencephalon
– Cerebral cortex
– Limbic system
– Basal ganglia
• Diencephalon
– Thalamus – sensory relay nuclei
– Hypothalamus
 Regulation of motivated behaviors
 Controls hormone release by the pituitary
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• Mesencephalon
– Tectum (dorsal surface)
• Inferior colliculi – audition
• Superior colliculi - vision
– Tegmentum (ventral) – 3 ‘colorful’ structures
• Periaqueductal gray – analgesia
• Substantia nigra – sensorimotor
• Red nucleus– sensorimotor
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• Myelencephalon = medulla
– Composed largely of tracts
– Origin of the reticular formation
• Metencephalon
– Many tracts
– Pons – ventral surface
– Cerebellum - coordination
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THE CENTRAL NERVOUS SYSTEM
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THE CENTRAL NERVOUS SYSTEM
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THE CENTRAL NERVOUS SYSTEM
• The forebrain-telencephalon
• Cerebrum
– The largest structure of the human brain, consisting of the two
cerebral hemispheres connected by the corpus callosum and covered
by the cerebral cortex
– The most rostral of the three major divisions of the brain; includes
the telencephalon and diencephalon.
– Convolutions serve to increase surface area.
– Longitudinal fissure – a groove that separates right and left
hemispheres
– Corpus callosum – largest hemisphere-connecting tract
– The thick band of nerve fibers that connects the two cerebral
hemispheres and makes possible the transfer of information and the
synchronization of activity between them
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• The forebrain-telencephalon
• Cerebrum
– Cerebral hemispheres
• The right and left halves of the cerebrum, covered by the
cerebral cortex and connected by the corpus callosum
• One of the two major portions of the forebrain, covered by the
cerebral cortex.
– Cerebral cortex
• The gray, convoluted covering of the cerebral hemispheres that is
responsible for higher mental processes including language,
memory, and thinking
• Referred to as gray matter
• Andreason and others
• Indicated that the amount of gray matter is positively
correlated with human intelligence
• Convolutions
• The numerous folds or wrinkles in the cortex
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• The forebrain-telencephalon
• Cerebral cortex
– Three types of areas of the cerebral cortex
• Sensory input areas: where vision, hearing, touch,
pressure, and temperature register
• Motor areas: control voluntary movement
• Association areas: house memories and are involved in
thought, perception, and language
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• The forebrain-telencephalon
– Subcortical region
• The region located within the brain, beneath the cortical surface.
• Contains the limbic system and the basal ganglia.
– Sulcus
• A groove in the surface of the cerebral hemisphere, smaller than a
fissure.
– Fissure
• A major groove in the surface of the brain, larger than a sulcus.
– Gyrus
• A convolution of the cortex of the cerebral hemispheres, separated
by sulci or fissures.
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• The forebrain-telencephalon
– Primary visual cortex
• The region of the posterior occipital lobe whose primary input is
from the visual system.
– Calcarine fissure
• A fissure located in the occipital lobe on the medial surface of the
brain; most of the primary visual cortex is located along its upper
and lower banks.
– Primary auditory cortex
• The region of the superior temporal lobe whose primary input is
from the auditory system.
– Lateral fissure
• The fissure that separates the temporal lobe from the overlying
frontal and parietal lobes.
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• The forebrain-telencephalon
– Primary somatosensory cortex
• The region of the anterior parietal lobe whose primary input is
from the somatosensory system.
– Central sulcus
• The sulcus that separates the frontal lobe from the parietal lobe.
– Primary motor cortex
• The region of the posterior frontal lobe that contains neurons that
control movements of skeletal muscle.
• The connections of this region are contralateral.
• The left primary motor cortex controls the right side
of the body and vice versa.
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• The forebraintelencephalon
– The Brain Lobes
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•
•
•
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
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The Frontal Lobes
• The anterior portion of the cerebral
cortex, rostral to the parietal lobe
and dorsal to the temporal lobe.
This includes everything in front of
the central sulcus (front of the
brain)
• Functions include
– motor cortex : control voluntary body
movements,
– Broca’s area : speech production
– the frontal association areas: memory
search, reasoning thinking,
motivation, planning for the future,
impulse control, and emotional
responses
• Phineas Gage
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• Motor cortex
– The strip of tissue at the rear of the frontal
lobes that controls voluntary body movement
– Discovered by Fritsch and Hitzig
– Wilder Penfield
• Applied electrical stimulation to the motor cortex of
conscious human patients undergoing neurosurgery
• Mapped the primary motor cortex in humans
– Plasticity is maintained throughout life
• The capacity of the brain to adapt to changes such
as brain damage
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The Parietal Lobes
• The region of the cerebral cortex caudal
to the frontal lobe and dorsal to the
temporal lobe (Top rear of the brain)
• The lobes that contain the somatosensory
cortex and other areas that are
responsible for
–
–
–
–
body awareness,
attention,
motor control and
spatial orientation
• Somatosensory cortex
– The strip of tissue at the front of the
parietal lobe where touch, pressure,
temperature, and pain register in the
cerebral cortex
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The Temporal Lobes
 The region of the cerebral cortex
rostral to the occipital lobe and
ventral to the parietal and frontal
lobes (in front of the ears)
 The lobes that contain the
primary auditory cortex,
Wernicke’s area (hearing), and
association areas for interpreting
auditory information, vision,
memory
 Primary auditory cortex:
 The part of the temporal lobes
where hearing registers in the
cerebral cortex
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The Occipital Lobes
• The region of the cerebral cortex
caudal to the parietal and temporal
lobes.
• This is located posterior to the central
sulcus (At the back of the head)
• The lobes that contain the primary
visual cortex and association areas
involved in the interpretation of visual
information
• Primary visual cortex
– The area at the rear of the occipital
lobes where vision registers in the
cerebral cortex
– Each eye is connected to the primary
visual cortex in both right and left
occipital lobes
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What Became of Albert
Einstein's Brain?
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Investigation for Student Centered learning
What Became of Albert Einstein's
Brain?
• On April 18, 1955, the great mathematician and physicist Albert
Einstein died. He was 76 years old.
• Einstein had requested that his body be cremated but that his
brain be saved and studied for research.
• Scientists counted the number of neurons (nerve cells) and glial
cells in four areas of Einstein’s brain: area 9 of the cerebral
cortex on the right and left hemisphere and area 39 of the
cerebral cortex on the right and left hemisphere.
• The ratios of neurons to glial cells in Einstein’s brain were
compared to those from the brains of 11 men who died at the
average age of 64.
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Clues
• Area 9 is located in the frontal
lobe (prefrontal cortex) and is
thought to be important for
planning behavior, attention
and memory.
• Area 39 is located in the
parietal lobe and is part of the
"association cortex."
• Area 39 is thought to be
involved with language and
several other complex
functions.
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• The forebrain-telencephalon
– Sensory association cortex
• Those regions of the cerebral cortex that receive
information from regions of the primary sensory
cortex. Perception takes place here and memories
are stored here.
– Motor association cortex (premotor cortex)
• The region of the frontal lobe rostral to the primary
cortex; also known as the premotor cortex. Controls
overall motor behavior.
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• The forebrain-telencephalon
– Prefrontal cortex
• The region of the frontal lobe rostral to the
motor association cortex. This region is involved
in formulating plans and strategies.
– Corpus callosum
• A large bundle of axons that interconnects
corresponding regions of the association cortex
on each side of the brain.
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• The forebrain-telencephalon
– Neocortex
• The phylogenetically newest cortex, including
the primary sensory cortex, primary motor cortex,
and association cortex.
– Limbic cortex
• Phylogenetically old cortex, located at the medial
edge of the cerebral hemispheres; part of the limbic
system.
– Cingulate gyrus
• A strip of limbic cortex lying along the lateral
walls of the groove separating the cerebral
hemispheres, just above the corpus callosum.
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• The forebrain-telencephalon
• Subcortical structures - Limbic system
• Regulation of motivated behaviors
• A group of brain regions including the anterior thalamic
nuclei, amygdala, hippocampus, limbic cortex, fornix,
cingulate, septum, mammillary bodies and parts of the
hypothalamus, as well as their interconnecting fiber
bundles.
• These structures in the brain are collectively involved in
emotion, memory, and motivation
– Hippocampus
• A forebrain structure in the limbic system (in the temporal
lobe) that plays a central role in the formation of long-term
memories
• Includes the hippocampus proper, dentate gyrus, and
subiculum.
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• Limbic system
– Fornix
• A fiber bundle that connects the hippocampus with
– other parts of the brain, including the mammillary
– bodies of the hypothalamus.
– Mammillary bodies
• A protrusion of the bottom of the brain at the
posterior end of the hypothalamus, containing
some hypothalamic nuclei.
• Serve as relay stations in reflexes related to the
sense of smell.
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• Limbic system
– Basal ganglia motor system
• Part of the telencephalon, including the caudate
nucleus, the globus pallidus, and the putamen.
• Parkinson’s disease is caused by degeneration
of the caudate nucleus and putamen.
• Parkinson’s disease includes weakness, tremors,
rigidity of the limbs, poor balance and difficulty initiating
movements.
• Amygdala, striatum (caudate nucleus + putamen), globus
pallidus
• Amygdala
• A structure in the limbic system (in the interior of the rostral temporal
lobe), containing a set of nuclei.
• plays an important role in emotion, particularly in response to aversive
stimuli
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• The forebrain-diencephalon
– Diencephalon
• Situated between the telencephalon and the mesencephalon.
• A region of the forebrain surrounding the third ventricle.
• The most important structures include the thalamus and the
hypothalamus.
– Thalamus (Greek thalamos, “inner chamber”)
• The largest portion of the diencephalon, located above the
hypothalamus; contains nuclei that project information to
specific regions of the cerebral cortex and receive information
from it.
– Projection fiber
• An axon of a neuron in one region of the brain whose
terminals form synapses with neurons in another region.
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• The forebrain-diencephalon
• Thalamus
– The structure, located above the brainstem, that acts as a
relay station for information flowing into or out of the
higher brain centers
– Regulates sleep cycles
– Lateral geniculate nucleus
• A nucleus of the thalamus that receives fibers from the retina and
projects fibers to the primary visual cortex.
– Medial geniculate nucleus
• A nucleus of the thalamus that receives fibers from the auditory
system and projects fibers to the auditory cortex.
– Ventrolateral nucleus
• A nucleus of the thalamus that receives inputs from
the cerebellum and sends axons to the primary motor cortex.
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• The forebrain-diencephalon
• Hypothalamus
• A group of nuclei in the diencephalon situated beneath the
thalamus.
• A small but influential brain structure that controls
the pituitary gland and regulates hunger, thirst,
sexual behavior, body temperature, and a wide
variety of emotional behaviors
• Controls the autonomic nervous system.
• Controls the anterior and posterior pituitary glands.
• Organizes behavior such as fighting, feeding, fleeing, and
mating.
• Includes:
•
•
•
•
Optic chiasm
Anterior pituitary gland
Neurosecretory cell
Posterior pituitary gland
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• The forebrain-diencephalon: Hypothalamus
– Optic chiasm
• A connection between the optic nerves where half of the fibers of the
optic nerve cross to the contralateral side
– Anterior pituitary gland
• The “master gland”.
• The anterior part of the pituitary gland; an endocrine gland whose
secretions are controlled by the hypothalamic hormones.
– Neurosecretory cell
• A neuron that secretes a hormone or hormonelike substance.
– Posterior pituitary gland
• The posterior part of the pituitary gland; an
endocrine gland that contains hormone-secreting
terminal buttons of axons whose cell bodies lie
within the hypothalamus.
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• The midbrainmesencephalon
– The midbrain; a region of the brain that
surrounds the cerebral aqueduct; includes
the tectum and tegmentum.
– The esencephalon; the central of the
three major divisions of the brain.
– The structures of this brain region act
primarily as relay stations through which
the basic physiological functions of the
hindbrain are linked to the cognitive
functions of the forebrain
– Substantia nigra
• The midbrain structure that controls
unconscious motor movements
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• The midbrain-mesencephalon
• Tectum (“roof”)
– The dorsal part of the midbrain; includes the
superior and inferior colliculi.
– Includes:
– Superior colliculi
– Inferior colliculi
– Brain stem
– Superior colliculi
• Protrusions on top of the midbrain; part of the
visual system.
• In mammals they are primarily involved in visual
reflexes and reactions to moving stimuli
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• The midbrain- mesencephalon
• Tectum (“roof”)
– Inferior colliculi
• Protrusions on top of the midbrain; part of the
auditory system.
egmentum (“covering”)
• The ventral part of the midbrain, includes the
periaqueductal gray matter, reticular formation,
red nucleus, and substantia nigra.
– Brain stem
• The stem of the brain, from the medulla to the
diencephalon, excluding the cerebellum.
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• The midbrain- mesencephalon
• Tegmentum
– Periaqueductal gray matter
• The region of the midbrain surrounding the cerebral aqueduct; contains
neural circuits involved in species-typical behaviors such as fighting and
mating; involved in sensitivity to pain.
– Red nucleus
• A large nucleus of the midbrain that receives inputs from the cerebellum
and motor cortex and sends axons to motor neurons in the spinal cord.
– Substantia nigra (“black substance”)
• A darkly stained region of the tegmentum that
contains neurons that communicate with the
caudate nucleus and putamen in the basal ganglia.
• Degeneration of the substantia nigra is involved
in Parkinson’s disease.
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• The hindbrain-metencephalon
• The most caudal part of the brain;
• includes the metencephalon and myelencephalon.
– Cerebellum (“little brain”)
• A major part of the brain located dorsal to the pons,
containing the two cerebellar hemispheres, covered
with the cerebellar cortex; important component of
the motor system.
• The brain structure that executes smooth, skilled body
movements and regulates muscle tone and posture
– Cerebellar cortex
• The cortex that covers the surface of the cerebellum.
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• The hindbrain-metencephalon
– Deep cerebellar nuclei
• Nuclei located within the cerebellar hemispheres;
receive projections from the cerebellar cortex and
send projections out of the cerebellum to other parts
of the brain.
– Brainstem
• The structure that begins at the point where the spinal
cord enlarges as it enters the brain
– Cerebellar peduncle
• One of three bundles of axons that attach each cerebellar
hemisphere to the dorsal pons.
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• The hindbrain-metencephalon
– Pons (“bridge”)
• The region of the metencephalon rostral to the medulla, caudal to the
midbrain, and ventral to the cerebellum;
• A structure in the brainstem that plays a role in body movement and
even exerts an influence on arousal, sleep and dreaming
– Reticular formation
• A structure in the brainstem that plays a crucial role in arousal and
attention and that screens sensory messages entering the brain
– Medulla oblongata
• The most caudal portion of the brain, located in the myelencephalon,
immediately rostral to the spinal cord.
• The part of the brainstem that controls vital functions such as the
cardiovascular system, respiration, and skeletal muscle tone
(breathing, coughing, and swallowing)
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Peripheral Nervous System
 Somatic Nervous System
 Afferent nerves (sensory)
 Efferent nerves (motor)
 controls organs under voluntary control (mainly
muscles)
 Autonomic Nervous System
 Sympathetic and parasympathetic nerves
 Sympathetic and parasympathetic nerves generally have
opposite effects
 Two-stage neural paths, neuron exiting the CNS
synapses on a second-stage neuron before the target
organ
 regulates individual organ function and homeostasis,
and for the most part is not subject to voluntary control73
Peripheral Nervous System
• Peripheral nervous system (PNS)
– The nerves connecting the central nervous system to
the rest of the body
– Contains two subdivisions
• Somatic division
• Autonomic division – contains two divisions
– Sympathetic division (activates)
– Parasympathetic division (inhibits)
Peripheral Nervous System
Peripheral Nervous System
• Somatic division
– Consists of all the sensory nerves, which transmit
information from the sense receptors—eyes, ears, nose,
tongue, and skin—to the central nervous system
– Consists of all the motor nerves, which relay messages
from the central nervous system to all the skeletal
muscles of the body
Peripheral Nervous System
• Autonomic division
– Operates without any conscious control or awareness on
your part
– Transmits messages between the central nervous system
and the glands, the cardiac muscle, and the smooth
muscles
Peripheral Nervous System
• Autonomic division (continued)
– Divided into two parts
• Sympathetic nervous system
– Mobilizes the body’s resources during stress, emergencies,
or heavy exertion, preparing the body for action
– Named the fight-or-flight response by Walter Cannon
• Parasympathetic nervous system
– Associated with relaxation and the conservation of energy;
the division that brings the heightened bodily responses
back to normal following an emergency
Autonomic Nervous System
•
•
•
•
Sympathetic
Thoracolumbar
“fight or flight”
Second stage
neurons are far
from the target
organ
Parasympathetic
Craniosacral
“rest and restore”
Second stage
neurons are near
the target organ
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Name each division of the nervous system and describe its role.
Nervous System
1. __________ Spinal
and Cranial Nerves
3. __________
Connect central system
to voluntary muscles
2. __________
Brain
Spinal Cord
4. __________
Connects central system
to nonvoluntary muscles
and glands
5. __________
Arousing; redies body
for activity; use of energy
6. __________
Calming; readies body
for restroation of energy
Copyright © Allyn & Bacon 2005
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•
•
•
•
•
Answers
Peripheral nervous system
Central nervous system
Somatic division
Autonomic division
Sympathetic division
Parasympathetic division
Copyright © Allyn & Bacon 2005
• Spinal cord
• The cord of nervous tissue that extends caudally from
the medulla, the base of the brain through the neck and
spinal column, that transmits messages between the
brain and the peripheral nervous system
• Protected by bone and spinal fluid
– Gray matter – inner component – primarily cell
bodies
– White matter – outer – mainly myelinated axons
– Dorsal – afferent, sensory
– Ventral – efferent, motor
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 Compare the relative amount of gray and white matter at each
level of the spinal cord. In the cervical segment, there is a
relatively large amount of white matter.
 This pattern is caused by the many axons going up to the
brain from all levels of the spinal cord AND there are many
axons traveling from the brain down to different segments of
the spinal cord.
 In lower segments of the spinal cord, there is less white
matter because there are fewer axons traveling to and from
the brain.
 There are also differences in the gray matter. In the cervical
segment, the ventral horn (the lower half of the segment) is
enlarged.
 Also in the lumbar segment that is illustrated, the ventral horn
is large.
 These segments are those that contain motor neurons that
control movement of the arms (cervical segment) and legs
(lumbar segment).
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The Spinal Cord
 The human spinal column is
made up of 33 bones: 7
vertebrae in the cervical
region, 12 in the thoracic
region, 5 in the lumbar region,
5 in the sacral region and 4 in
the coccygeal region.
 However, in adults the bones in
the sacral region join to form
one bone called the sacrum;
the bones in the cocygeal
region join to form one bone
called the coccyx.
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• Spinal cord
– Spinal root
• A bundle of axons surrounded by connective tissue that occur in pairs,
which fuse and form a spinal nerve.
– Cauda equina
• A bundle of spinal roots located caudal to the end of the spinal cord.
– Caudal block
• The anesthesia and paralysis of the lower part of the body produced by
injection of a local anesthetic into the cerebrospinal fluid surrounding the
cauda equina.
– Dorsal root
• The spinal root that contains
incoming (afferent) sensory fibers.
– Ventral root
• The spinal root that contains
the outgoing (efferent) motor fibers.
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• The Peripheral Nervous System
• The spinal nerves
– Afferent axon
• An axon directed toward the central nervous system, conveying sensory
information.
– Dorsal root ganglion
• A nodule on a dorsal root that contains cell bodies of afferent spinal nerve
neurons.
– Efferent axon
• An axon directed away from the central nervous system, conveying motor
commands to muscles and glands.
– Cranial nerves
• Twelve pairs of peripheral nerves attached directly to the brain that serve
sensory and motor functions of the head, neck, and shoulders.
– Vagus nerve (“wandering”)
• The largest of the cranial nerves, conveying efferent fibers of the
parasympathetic division of the autonomic nervous system to organs of
the thoracic and abdominal cavities.
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• The Peripheral Nervous System
• The autonomic nervous system
– Somatic nervous system
• The part of the peripheral nervous system
that controls the movement of skeletal muscles
or transmits somatosensory information to the
central nervous system.
– Autonomic nervous system
• The portion of the peripheral nervous system
that controls the body’s vegetative functions.
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• The Peripheral Nervous System
• The autonomic nervous system-sympathetic
division
– Sympathetic division
• The portion of the autonomic nervous system that controls functions that
accompany arousal and expenditure of energy.
– Sympathetic ganglia
• Nodules that contain synapses between preganglionic and postganglionic
neurons of the sympathetic nervous system.
– Preganglionic neuron
• The efferent neuron of the autonomic nervous system whose cell body is
located in a cranial nerve nucleus
or in the intermediate horn of the spinal gray matter
and whose terminal buttons synapse upon
postganglionic neurons in the autonomic nervous system.
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• The Peripheral Nervous System
• The autonomic nervous system-sympathetic
division
– Postganglionic neuron
• Neurons of the autonomic nervous system that form synapses
directly with their target organ.
– Adrenal medulla
• The inner portion of the adrenal gland, located
atop the kidney, controlled by sympathetic nerve
fibers; secretes epinephrine and norepinephrine.
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• The Peripheral Nervous System
• The autonomic nervous systemparasympathetic division
• The portion of the autonomic nervous system that controls
functions that occur during a relaxed state.
• Supports activities involved with increases in the body’s supply
of stored energy including salivation, gastric and intestinal
motility, secretion of digestive juices, and increased blood flow
to the gastrointestinal system.
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Endocrine System
• Endocrine system
– A system of ductless glands in various parts of the body
that manufacture and secrete hormones into the
bloodstream or lymph fluids, thus affecting cells in other
parts of the body
– Hormones
• A substance manufactured and released in one part of the body
that affects other parts of the body
Endocrine System
Endocrine System
• Pituitary gland
– The endocrine gland located in the brain and
often called the “master gland,” which releases
hormones that control other endocrine glands
and which also releases a growth hormone
– Thyroid gland
– Produces the important hormone thyroxin,
which regulates the rate at which food is
metabolized
Endocrine System
Endocrine System
• Pancreas
– Regulates the body’s blood sugar levels by
releasing the hormones insulin and glucagon
into the bloodstream
• Adrenal glands
– A pair of endocrine glands that release
hormones that prepare the body for
emergencies and stressful situations and also
release small amounts of the sex hormones
Endocrine System
• Gonads
– Sex glands; the ovaries in females and the testes
in males
– Release the sex hormones that make
reproduction possible and that are responsible
for the secondary sex characteristics