1. FEM 4100
Topic 2
BRAIN ANATOMY

2. THE NERVOUS SYSTEM Two parts of a nervous system
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

3. 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 2 2

4. 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 2 2

5. 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 2 2

6. Central Nervous System
Cerebellum
The brain structure that executes smooth, skilled body movements and regulates muscle tone and posture 2 2

7. 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 2 2

8. 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 2 2

9. 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 2 2

10. Central Nervous System2 2

11. THE NERVOUS SYSTEM

12. BASIC FEATURES OF THE NERVOUS SYSTEM
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.

14. Rostral & caudal Rostral Caudal Dorsal & ventral Dorsal Ventral
“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.

15. Ipsilateral or Contralateral
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.

16. Cross section or Frontal section
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

19. 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

20. Meninges, Ventricles, and CSF
MENINGES, VENTRICLES & 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

22. The Five Major Divisions of the Brain

24. 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

25. Mesencephalon Tectum (dorsal surface)
Inferior colliculi – audition
Superior colliculi - vision
Tegmentum (ventral) – 3 ‘colorful’ structures
Periaqueductal gray – analgesia
Substantia nigra – sensorimotor
Red nucleus– sensorimotor

26. Myelencephalon = medulla
Composed largely of tracts
Origin of the reticular formation
Metencephalon
Many tracts
Pons – ventral surface
Cerebellum - coordination

27. THE CENTRAL NERVOUS SYSTEM

28. THE CENTRAL NERVOUS SYSTEM

29. 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

30. 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

31. 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

32. 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.

34. 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.

35. 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.

37. The forebrain-telencephalon
The Brain Lobes
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe

38. 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

39. 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

40. 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

41. 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

42. 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

43. What Became of Albert Einstein's Brain?

44. What Became of Albert Einstein's Brain?
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.

45. 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.

46. 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.

47. 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.

48. 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.

50. 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.

52. Limbic system Fornix Mammillary bodies
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.

54. 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

56. The forebrain-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.

58. 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.

61. 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

62. 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 hormone-
like 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.

65. The midbrain-mesencephalon
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

66. The midbrain-mesencephalon Tectum (“roof”)
The dorsal part of the midbrain; includes the superior and inferior colliculi.
Includes:
Superior colliculi
Inferior colliculi
Brain stem
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

67. 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.

68. 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.

70. 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.

71. 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.

72. 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)

73. 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 control

74. 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) 2 2

75. Peripheral Nervous System2 2

76. 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 2 2

77. 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 2 2

78. 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 2 2

79. Autonomic Nervous System
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

80. Copyright © Allyn & Bacon 2005

81. Copyright © Allyn & Bacon 2005
Answers
Peripheral nervous system
Central nervous system
Somatic division
Autonomic division
Sympathetic division
Parasympathetic division
Copyright © Allyn & Bacon 2005 2 2

82. Spinal cord Gray matter – inner component – primarily cell bodies
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

84. 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).

85. 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.

86. Spinal cord Spinal root Cauda equina Caudal block Dorsal 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 outgoing (efferent) motor fibers.

87. 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.

91. 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.

92. 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.

93. 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.

94. The Peripheral Nervous System
The autonomic nervous system-parasympathetic 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.

96. 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 2 2

97. Endocrine System 2 2

98. 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 2 2

99. Endocrine System 2 2

100. Endocrine System Pancreas Adrenal glands
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 2 2

101. 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 2 2