Human Anatomy and Physiology Chapter 12: The Spinal Cord, Spinal Nerves, and Spinal Reflexes
step 1 of reflex
arrival of stimulus and activation of receptor
11% of brain mass
cerebellum
40% of the mass of the brain
cerebral cortex
A fissure is a
deep sulcus
Subdural or subarachnoid hemorrhage
may force brain stem through the foramen magnum, resulting in death
Centers for coughing, sneezing, swallowing and vomiting are found here
medulla oblongata
Forms part of the ventral wall of the fourth ventricle
medulla oblongata
Joins spinal cord at foramen magnum
medulla oblongata
Transmits all ascending and descending impulses
medulla oblongata
Pons nuclei help regulate
respiration
Cerebral edema
swelling of the brain associated with traumatic head injury
Gray matter is
unmyelinated
Cauda equina
"horse's tail", a fan of nerve fibers below the spinal cord
Composition of CSF
*Watery solution *Less protein and different ion concentrations than plasma *Constant volume
Prefrontal cortex
*Working memory for spatial tasks *Executive area for task management *Working memory for object-recall tasks *Solving complex, multitask problems
What is the most reasonable explanation for why meningitis (an infection in the meninges) would damage the spinal cord?
Meningitis would place physical pressure on the spinal cord
What are the three types of functional areas of the cerebral cortex?
Motor areas Sensory areas Association areas
A patient with severe West Nile virus impacting the anterior gray horn would likely exhibit
Paralysis of some muscles
degeneration of the dopamine-releasing neurons of the substantia nigra
Parkinson's disease
Forms part of the anterior wall of the fourth ventricle
Pons
Thoracic spinal nerves
12 pairs
How many enlargements are in the spinal cord?
2
How many pairs of spinal nerves are there?
31
Origin of cranial nerves V (trigeminal), VI (abducens), and VII (facial)
Pons
A typical spinal cord has how many pairs of spinal nerves, and where does the spinal cord end?
31 pairs; lumbar vertebra 1 or 2
Sacral spinal nerves
5 pairs
How many lobes does the brain have?
5: frontal, parietal, temporal, occipital, insula
cervical spinal nerves
8 pairs
blood-brain barrier
A mechanism that prevents certain molecule from entering the brain but allows others to cross
Temporal lobe
A region of the cerebral cortex responsible for hearing and language.
Occipital lobe
A region of the cerebral cortex that processes visual information
Parietal lobe
A region of the cerebral cortex whose functions include processing information about touch.
a progressive degenerative disease of brain that results in dementia
Alzheimer's disease (AD)
Involves progressive destruction of ventral horn motor neurons and fibers of the pyramidal tract
Amyotrophic Lateral Sclerosis (ALS)
Hearing
Auditory association area Primary auditory cortex
Four modes of protection for the brain
Bone (skull) Membranes (meninges) Watery cushion (cerebrospinal fluid) Blood-brain barrier
-Midbrain -Pons -Medulla oblongata
Brain Stem
Associated with 10 of the 12 pairs of cranial nerves
Brain Stem
Contains fiber tracts connecting higher and lower neural centers
Brain Stem
Controls automatic behaviors necessary for survival
Brain Stem
Similar structure to spinal cord but contains embedded nuclei
Brain Stem
The collection of nerve roots at the inferior end of the vertebral canal
Cauda equina
If West Nile virus invades the anterior gray horn of the spinal cord, what cells types and parts would most likely be damaged?
Cell bodies of motor neurons
Coordinates skeletal muscle movement and maintains posture and balance
Cerebellum
Two hemispheres connected by vermis
Cerebellum
Gives buoyancy to the CNS organs
Cerebrospinal Fluid (CSF)
Nourishes the brain and carries chemical signals
Cerebrospinal Fluid (CSF)
Protects the CNS from blows and other trauma
Cerebrospinal Fluid (CSF)
What is the subarachnoid space?
Cerebrospinal Fluid (CSF)
Blood circulation is blocked and brain tissue dies(blockage of a cerebral artery by a blood clot)
Cerebrovascular accidents (strokes)
Typically leads to hemiplegia, or sensory and speed deficits
Cerebrovascular accidents (strokes)
The nerves serving the upper and lower limbs emerge here
Cervical and lumbar enlargements
What are the Motor areas of the brain?
Primary (somatic) motor cortex Premotor cortex Broca's area Frontal eye field
Somatic sensation
Primary somatosensory cortex Somatosensory association cortex
Transection
Cross sectioning of spinal cord at any level results in total motor and sensory loss in regions inferior to cut.
Vision
Primary visual cortex Visual association area
carry motor impulses to muscles and glands
Descending Pathways
interneurons that receive somatic and visceral sensory input
Dorsal horns
contain cell bodies of sensory neurons
Dorsal root (spinal) ganglia
CSF in subarachnoid space
Protection feature of the spinal cord
Cushion of fat and a network of veins in the epidural space between the vertebrae and spinal dura mater
Protection feature of the spinal cord
Which efferent nerve is involved in the plantar reflex?
Tibial nerve
step 4 of reflex
activation of a motor neuron
step 2 of reflex
activation of a sensory neuron
When does the activation of a motor neuron occur in a stretch reflex?
after information processing in the CNS
somatic motor neurons whose axons exit the cord via ventral roots
Ventral horns
Connected to one another and to the central canal of the spinal cord
Ventricles of the Brain
Lined by ependymal cells
Ventricles of the Brain
petit mal or grand mal seizures
Epilepsy
What are the four regions of the brain?
cerebrum, diencephalon, brainstem, cerebellum
What are the two enlargements of the spinal cord?
cervical and lumbar
Quadriplegia—transection in the
cervical region
Choroid Plexus located
Epithalamus
Most dorsal portion of the diencephalon
Epithalamus
Pineal gland secretes melatonin
Epithalamus
Impulses do not reach muscles
Flaccid paralysis
No voluntary or involuntary control of muscles
Flaccid paralysis
severe damage to the ventral root or ventral horn cells
Flaccid paralysis
Mediates sensation, motor activities, cortical arousal, learning, and memory
Function of Thalamus
Two way communication between brain and body
Function of the spinal cord
cerebral sulcus
Grooves between cerebral gyri
Taste
Gustatory cortex (in insula)
fatal hereditary disorder from accumulation of the protein huntingtin; leads to degeneration of basal nuclei and cerebral cortex
Huntington's disease
Autonomic control center for many visceral functions (e.g., blood pressure, rate and force of heartbeat, digestive tract motility)
Hypothalamus
Center for emotional response
Hypothalamus
Controls release of hormones by the anterior pituitary
Hypothalamus
Forms the inferolateral walls of the third ventricle
Hypothalamus
Involved in perception of pleasure, fear, rage and in biological rhythms and drives
Hypothalamus
Produces posterior pituitary hormones
Hypothalamus
Regulates body temperature, food intake, water balance, and thirst
Hypothalamus
Regulates sleep and the sleep cycle
Hypothalamus
Cerebral hemisphere
Identify #1
Parietal lobe (identify)
Identify #1
axon (identify)
Identify #1
posterior (dorsal) root of spinal nerve (identify)
Identify #1
Pons (midsagittal view)
Identify #10
Precentral gyrus
Identify #10
Solving complex, multitask problems
Identify #10
Medulla oblongata (midsagittal view)
Identify #11
Postcentral gyrus
Identify #11
Working memory for object-recall tasks
Identify #11
Spinal cord (attached to brain midsagittal view)
Identify #11 (the bottom one)
Central sulcus
Identify #12
Corpus callosum (midsagittal view)
Identify #12
Executive area for task management
Identify #12
Fornix (midsagittal view)
Identify #13
Working memory for spatial tasks
Identify #13
Broca's area (outlined by dashes)
Identify #14
Choroid plexus (midsagittal view)
Identify #14
Frontal eye field
Identify #15
Thalamus (encloses third ventricle) (identify)
Identify #15
Posterior commissure (midsagittal view)
Identify #16
Pineal gland (part of epithalamus) (identify)
Identify #17
Corpora quadrigemina
Identify #19
Endoneurium (identify)
Identify #2
Parieto-occipital sulcus (on medial surface of hemisphere)
Identify #2
Primary somatosensory cortex
Identify #2
Septum pellucidum
Identify #2
anterior (ventral) root of spinal nerve (identify)
Identify #2
Cerebral aqueduct (midsagittal view)
Identify #20
Arbor vitae (of cerebellum) (identify)
Identify #21
Fourth ventricle (midsagittal view)
Identify #22
Choroid plexus (inferior one of midsagittal view)
Identify #23
Cerebellum (midsagittal view)
Identify #24
Midbrain (midsagittal view)
Identify #25
Interthalamic adhesion(intermediate mass of thalamus)
Identify #3
Occipital lobe (identify)
Identify #3
Perineurium (identify)
Identify #3
Somatosensory association cortex
Identify #3
pia mater of spinal cord (identify)
Identify #3
Gustatory cortex (in insula)
Identify #4
Interventricular foramen
Identify #4
arachnoid mater of spinal cord (identify)
Identify #4
epineurium (identify)
Identify #4
Anterior commissure
Identify #5
Perimysium (identify)
Identify #5
Wernicke's area (outlined by dashes)
Identify #5
dura mater of spinal cord (identify)
Identify #5
Fascicle (identify)
Identify #6
Hypothalamus (identify)
Identify #6
Primary visual cortex
Identify #6
posterior (dorsal) root ganglion (identify)
Identify #6
Myelin sheath (identify)
Identify #7
Optic chiasma (identify)
Identify #7
Temporal lobe (identify)
Identify #7
Visual association area
Identify #7
spinal nerve (identify)
Identify #7
Auditory association area
Identify #8
Lateral sulcus
Identify #8
Pituitary gland
Identify #8
Mammillary body
Identify #9
Primary auditory cortex
Identify #9
Dorsal funiculus
Identify A
Frontal lobe (identify)
Identify A
Pia mater
Identify A
Superior Cerebellar peduncle
Identify A
dura mater
Identify A
Anterior lobe of cerebellum
Identify B
Arachnoid mater
Identify B
Middle Cerebellar peduncle
Identify B
Ventral funiculus
Identify B
periosteal layer
Identify B
Arbor vitae (identify)
Identify C
Dura mater
Identify C
Inferior Cerebellar peduncle
Identify C
Lateral funiculus
Identify C
meningeal layer
Identify C
Arachnoid mater (skull slide)
Identify D
Spinal meninges
Identify D
White columns
Identify D
Bone of vertebra
Identify E
Cerebellar cortex (identify)
Identify E
Dorsal root ganglion
Identify E
Pia mater (skull slide)
Identify E
Arachnoid villus
Identify F
Posterior lobe of cerebellum
Identify F
Spinal nerve
Identify F
Body of vertebra
Identify G
Choroid plexus of fourth ventricle
Identify G
Dorsal root (fans out into dorsal rootlets)
Identify G
Flocculonodular lobe
Identify H
Subarachnoid space(contains CSF)
Identify H
Ventral root (derived from several ventral rootlets)
Identify H
Dorsal median sulcus
Identify I
Subdural space
Identify I
Epidural space(contains fat)
Identify J
Gray commissure
Identify J
Transverse cerebral fissure
Identify J
Cerebellum (identify)
Identify K
Dorsal horn
Identify K
Pons (identify)
Identify L
Ventral horn
Identify L
Lateral horn
Identify M
Medulla oblongata (identify)
Identify M
Gray matter
Identify N
Central canal
Identify O
Ventral median fissure
Identify P
Pia mater (spinal cord slide)
Identify Q
Arachnoid mater (spinal cord slide)
Identify R
Spinal dura mater
Identify S
Lumbar spinal nerves (identify)
Identify these nerves
Bone, meninges, and CSF
What is the spinal cord protected by?
Consists mostly of ascending (sensory) and descending (motor) tracts
White Matter
Each spinal tract is composed of axons with similar functions
White Matter
Produces cerebrospinal fluid
choroid plexus
The Pons is mainly a
conducting area
Cerebellar peduncles
connect the cerebellum to the brainstem
Cerebral cortex is site of the
conscious mind
intermediate mass of thalamus
Interthalamic adhesion
Each hemisphere connects to
contralateral (opposite) sides of the body
Spastic paralysis
damage to upper motor neurons of the primary motor cortex
What type of cells are ventricles of the brain lined with?
ependymal cells
cerebral fissure
separates cerebral hemispheres
RAS (reticular activating system)
special group of reticular formation neurons that plays a role in consciousness and the awake/sleep cycles
Define gray matter in the spinal cord.
It contains the cell bodies of neurons, neuroglia, and unmyelinated axons, and it surrounds the narrow central canal.
sympathetic neurons
Lateral horns (only in thoracic and lumbar regions)
connected with math and language skills, and logic
Left hemisphere
Includes parts of the diencephalon and some cerebral structures that encircle the brain stem
Limbic System
Modifies behavior
Limbic System
Produces emotions - anger, fear, conflict
Limbic System
Structures on the medial aspects of cerebral hemispheres and diencephalon
Limbic System
The thalamus and hypothalamus is part of the
Limbic System
deep grooves
fissures
Wernicke's area function
speech comprehension
Broca's area function
speech production
Central cavity surrounded by a gray matter core
spinal cord
External white matter composed of myelinated fiber tracts
spinal cord
Where is spinal CSF located?
subarachnoid space
shallow grooves
sulci (sulcus)
Cervical enlargement
supplies nerves to the shoulder and upper limbs
Conus medullaris
tapered, conical portion of the spinal cord inferior to the lumbar enlargement
Which lobe controls hearing?
temporal
Which lobe controls speech?
temporal
Concussion
temporary alteration in function
Transient ischemic attacks (TIAs)
temporary episodes of reversible cerebral ischemia
80% of diencephalon
thalamus
Gateway to the cerebral cortex
thalamus
What encloses the third ventricle?
thalamus
Cerebellum
the "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance
third lobe of cerebellum
flocculonodular
Insula lobe
found deep beneath the lateral sulcus, associated with memory and interpretation of taste
Which lobe controls motor functions?
frontal lobe
Mostly neuron cell bodies and unmyelinated fibers
gray matter
Superficial layer of the cerebral cortex
gray matter
contralateral
opposite side
sensory lobes
parietal, temporal, occipital and insular lobes
Gustatory cortex
perception of taste
Contusion
permanent damage
second lobe of cerebellum
posterior
Somatosensory association cortex is located
posterior to the primary somatosensory cortex
Medulla oblongata function
regulating vital function (breathing, digestion, heart rate)
Nuclei in the medulla regulate
respiratory rhythm, heart rate, blood pressure
step 5 of reflex
response by effector
Left hemisphere controls
right side of the body
Parasthesias
sensory loss
CNS consists of
the brain and spinal cord
Conscious behavior involves
the entire cortex
Primary motor cortex
the section of the frontal lobe responsible for voluntary movement
Cerebrum function
thinking, personality, sensations, movements, memory
Cushion of fat and a network of veins in the epidural space between the
vertebrae and spinal dura mater
Dense collections of myelinated fibers
white matter
A disease that damages myelin sheaths would affect which portion of the spinal cord?
white matter columns
Dorsal root ganglion (cross section view)
Identify F
carry sensory impulses to the brain
Ascending Pathways
First lobe of cerebellum
anterior
Maintains an alert state in the cerebral cortex
Reticular Formation
Severe injury results in permanent unconsciousness (coma)
Reticular Formation
Three broad columns of nuclei along the length of the brain stem
Reticular Formation
has far-flung axonal connections with hypothalamus, thalamus, cerebral cortex, cerebellum, and spinal cord
Reticular Formation
What are three surface markings of the cerebral hemisphere?
Ridges (gyri) shallow grooves (sulci) deep grooves (fissures)
insight, visual-spatial skills and creativity
Right hemisphere
Describe the direction of sensory input and motor commands relative to the spinal cord
Sensory input travels toward the spinal cord and motor commands travel away from the spinal cord.
Filum terminale
Slender fibrous strand that extends to the coccyx providing longitudinal support to the spinal cord
Function of Thalamus
Sorts, edits, and relays information
No voluntary control of muscles
Spastic paralysis
Spinal neurons remain intact; muscles are stimulated by reflex activity
Spastic paralysis
Paraplegia—transection between
T1 and L1
Frontal lobe
The lobe at the front of the brain associated with movement, speech, and impulsive behavior.
Cortex (gray matter)
The outer layer (approximately one-fourth to one-half inch) of brain tissue containing nerve cell bodies (neurons)
Premotor cortex
The region controlling learned motor skills.
The largest part of the brain is called the
cerebrum
Dorsal to the pons and medulla
cerebellum
Subconsciously provides precise timing and appropriate patterns of skeletal muscle contraction
cerebellum
Where is the Arbor vitae?
cerebellum
Channel between third and fourth ventricles
cerebral aqueduct
Site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding
cerebral cortex
Superficial layer of gray matter
cerebral cortex
Where is the site of the conscious mind?
cerebral cortex
Two C-shaped lateral ventricles in the
cerebral hemispheres
Four Ventricles filled with
cerebrospinal fluid
Third ventricle in the
diencephalon
Three layers of meninges
dura mater, arachnoid mater, pia mater
ridges
gyri (gyrus)
Fourth ventricle in the
hindbrain, dorsal to the pons
Cauda equina translates to
horse's tail
Primary somatosensory cortex is located
immediately behind the central sulcus
Transection results in total motor and sensory loss in regions _________ to the cut
inferior
step 3 of reflex
information processing in the CNS
Which lobe controls vision?
occipital
The cerebral cortex is 40%
of the mass of the brain
Right hemisphere controls
left side of the body
Anterior, posterior, and flocculonodular
lobes of the cerebellum
Paralysis
loss of motor function
Helps regulate sleep-wake cycles
melatonin
Contain cerebrospinal fluid (CSF)
meninges
Cover and protect the CNS
meninges
Form partitions in the skull
meninges
Protect blood vessels and enclose venous sinuses
meninges
Cerebral aqueduct located
midbrain
Located between the diencephalon and the pons
midbrain
Reflex centers for eye and head movement
midbrain
White matter is
myelinated
The white matter of the spinal cord is mainly
myelinated axons.
Lumbar enlargement
nerves of pelvis and lower limbs
