Pathophysiology Exam #2 Flashcards
(373 cards)
1
Q
What the two categories of bones that makes up the skull?
A
Neurocranium (brain case) and the Viscerocranium (face)
2
Q
What are the paired bones of the neurocranium?
A
Parietal bone and the temporal bone
3
Q
What are the unpaired bones of the neurocranium?
A
Frontal bone, sphenoid bone, occipital bone and the ethmoid bone
4
Q
What are the paired bones of the viscerocranium?
A
Maxilla bone, zygomatic bone, palatine bone, lacrimal bone and the nasal bone
5
Q
What are the unpaired bones of the viscerocranium?
A
Mandible and the Vomer bone.
6
Q
How many total bones make up the skull (cranium) of the axial skeleton?
A
22
7
Q
If your looking at a superior view of the skull…. what is the view?
A
From the top looking down
8
Q
What is the suture that separates the frontal bone from the parietal bones?
A
The Coronal Suture
9
Q
What suture line separates the right and left parietal bones?
A
The Sagittal suture
10
Q
What suture line separates the occipital bone of the skull from the parietal bones?
A
The Lambdoid suture
11
Q
If your looking at a posterior view of the skull what are you looking at?
A
The back of the skull
12
Q
What other bones does the Lambdoid suture line separate the Occipital bone from?
A
The left and right temporal bones
13
Q
What is the bone that is filled with air that conducts sound impulses from the outer ear to the inner ear. It is also part of the Temporal bone?
A
The Mastoid Process
14
Q
What paired bone does the first vertebrae (Atlas) of the vertebral column articulate with?
A
The Occipital condyles
15
Q
What does the lateral view of the skull show?
A
The skull from a side view
16
Q
What large bone of the skull forms the tops of the eye orbits?
A
The Frontal bone
17
Q
What is the name of the suture line that separates the Temporal bone from the Parietal bone?
A
Squamous suture
18
Q
What is the name of the condyle in which the mandible articulates with the Temporal bone?
A
The Mandibular Condyle
19
Q
The Zygomatic arch is part of what bone?
A
The Temporal bone
20
Q
The proper name of the jawbone is what?
A
The mandible
21
Q
What is the name of the bone that is superior to the mandible located between the oral cavity and the nares?
A
The Maxilla
22
Q
What does the description of the word foramen?
A
Its an opening
23
Q
An anterior view of the skull is from what angle?
A
From the front
24
Q
What is a fissure of a bone?
A
A fairly wide separation between bones
25
How does a canal differ from a foramen or a fissure?
They are an elongated area in which something passes through.
26
What part of the eye orbit does the Frontal bone contribute?
The roof of the orbit
27
What part of the eye orbit does the Sphenoid bone contribute?
Part of the roof and the lateral wall
28
What two parts of the orbit of the eye does the Zygomatic bone contribute?
Part of the roof and the lateral wall
29
What bone makes up the floor of the eye orbit?
The Maxilla
30
What three bones compose the medial wall of the eye orbit?
The Lacrimal, Ethmoid and Palatine bones
31
Is the Infraorbital Foramen in the eye orbit?
No it is located below the orbit as part of the Mandible
32
What is the name of the structures of the frontal bone that holds the inferior parts of the frontal lobes of the brain?
Left and Right Anterior Cranial Fossa
33
What is the importance of the Crista galli?
The dura mater that surrounds the brain attaches to the Crista galli which helps to hold the brain in place
34
What bone is the Critsa Galli part of?
The Ethmoid bone
35
What does the name Crista galli mean?
Cocks Comb
36
The optic foramen is located within what unpaired bone of the skull?
Within the Lesser Wing of the Sphenoid Bone
37
What is the name of the structure in which the anterior posterior pituitary glands sit?
Sella turcica
38
What is the meaning of the name Sella turcica?
Turkish saddle
39
What bone is the Sella turcica part of?
The greater wing of the Sphenoid bone
40
What is the only part of the pituitary gland that is not surrounded by bone?
The most superior aspect-→if the pituitary enlarges its only option is to grow up and out of Sella turcica into the space that optic nerves lie.
41
Due to the anatomy, what deficit is created if the pituitary gland enlarges?
Visual field deficit due to its impeding upon the optic nerves on the Sella turcica’s superior aspect
42
What two areas make up the unpaired Sphenoid bone?
Greater and Lesser Wing of the Sphenoid
43
Where do the inferior parts of the temporal lobes of the brain sit?
Middle Cranial Fossa right and left
44
What is the opening that cranial nerve 8 passes through?
Internal acoustic meatus
45
Where does the superior part of the spinal cord junction with the inferior part of the brain stem?
Foramen magnum-→junction between spinal cord and brain stem
46
What is the largest opening of the skull?
Foramen magnum
47
What does the inferior parts of the occipital lobes of the brain sit in?
Posterior cranial fossa
48
The Frontal sinuses are ____ - filled.
Air
49
What is the inferior perspective of the skull?
From the bottom
50
What articulates with the Occipital condyle?
C1 atlas
51
In adults the Foramen lacerum is…
Filled with cartilage
52
In what bone is the Carotid canal found?
Temporal
53
What passes through the carotid canal?
Internal carotid artery and Sympathetic nerve plexus
54
In what bone is the External auditory meatus found?
Temporal bone
55
What passes through the External auditory meatus?
Sound waves to the eardrum
56
In what bone is the Internal auditory meatus found?
Temporal bone
57
What passes through the Internal auditory meatus?
CN VII (facial exits) and CN VIII (auditory)
58
Between what two bones is the Jugular foramen found?
Between the temporal and occipital bones
59
What structures pass through the Jugular foramen?
Internal jugular vein (most venous blood from brain to right side of the heart), CN IX (glossopharyngeal, CN X (vagus), CN XI (spinal accessory)
60
In what bone is the Optic foramen located?
Sphenoid bone
61
What structures pass through the Optic foramen?
CN II (optic) and the Ophthalmic artery (major artery that perfuse eyeball
62
In what bone are the Superior orbital fissures located?
Sphenoid
63
What structures pass through the Superior orbital fissures?
CN III (oculomotor), CN IV (trochlear), CN V (trigeminal ophthalmic division), CN VI (abducens), Ophthalmic veins
64
What bone does the Foramen magnum pass through?
Occipital bone
65
What structures pass through the Occipital bone via the Foramen magnum?
Spinal cord/inferior medulla oblongata, CN XI (spinal accessory), Vertebral arteries (pass upwards…also passes blood to brain)
66
What separates the right and left hemisphere of the brain?
Longitudinal fissure
67
What is a fissure?
A wide and deep separation between anatomical structures
68
What is the Longitudinal fissure?
It runs the entire length of the brain separating the right and left hemispheres
69
What separates the Parietal lobe from the Frontal lobe?
The Central sulcus
70
What is a sulcus?
an indentation of the surface of the brain
71
What is the very front part of the Frontal lobe called?
The Prefrontal lobe
72
What are gyri(gyrus)?
Up foldings on the surface of the brain
73
Where is the Pre central gyrus located?
Located in the Frontal lobe, it is anterior to the Central sulcus
74
Where is the Post central gyrus located?
Located in the Parietal lobe, it is posterior to the Central sulcus
75
What is the specific anatomical separation between the Parietal and the Occipital lobes of the brain?
There is no specific anatomical separation. The division is based on function.
76
What is the Lateral fissure of the brain?
The Lateral fissure separates the Temporal lobe from all of the Frontal lobe and most of the Parietal lobes of the brain.
77
What is the Corpus callosum?
Located in the middle of the brain, consist of axons of tracks from one cerebral hemisphere to the other cerebral hemisphere, it connects the right and left hemispheres
78
What is the Corpus callosum function?
Allows the right and left brain a connection so each hemisphere knows what the other hemisphere is doing. If severed the right and left sides of the brain/body do know communicate with the other side.
79
What is the largest component of the Diencephalon?
the Thalamus
80
What are the 4 components of the Diencephalon?
Thalamus
Hypthalamus
Epithalamus
Subthalamus
81
Where does the brainstem end?
The foramen magnum of the skull
82
What are 4 components of the Brainstem?
Midbrain Pons Medulla oblongata Reticular formation
83
Ascending and descending spinal tracts pass this area of the Brainstem that is the most inferior of the 4 categories of the Brainstem.
Medulla oblongata
84
What is the structure located in the anterior inferior medulla oblongata?
Pyramidal decussation
85
What is the function of the Pyramidal decussation?
It is the area in the lower medulla where many descending somatic motor pathways cross over and continue descending on the opposite side of the spinal cord. They decussate or cross over -----\>(hence Pyramidal DECUSSATION!) and continue descending. Because of the Pyramidal decussation, motor centers on the right side of the brain can regulate moment on the left side of the body and motor control centers on the left side of the brain can regulate movement on the right side of the body.
86
What is the function of the Olive on/in the Medulla oblongata?
Involved in the transmission of sound impulses and balance. Inner ear to higher parts of the brain.
87
Inspiratory and expiratory centers are located in the?
Medulla oblongata
88
What cranial nerves have their origin in the medulla?
9(glossopharyngeal), 10(vagus), 11(spinal accessory), 12(Hypoglossal)
89
What is the function of the Nucleus cuneatus and the Nucleus gracilis?
Important areas of the Medulla oblongata, they are components of ascending sensory pathways. These ascending sensory pathways pass through either the Nucleus cuneatus or the Nucleus gracilis.
90
What is the related functions of the Raphe magnus nucleus, Reticularis paragigantocellularis of the Medulla and the Periaqueductal gray matter of the Pons?
These structures are concerned with modulation of pain transmission. They have lots of opioid(kappa delta) receptors and many opioid peptides are found within the synapses of this area. \*\*\*\*PAIN TRASMISSION PATHWAYS\*\*\*\*\*
91
When individual nuclei within the brain is referred too what is the reference?
clusters of gray matter within the brain, nerve cell bodies and their dendrites where probably axons synapse with dendrites. \*\*\*\*EACH SPECIFIC NUCLEUS HAS ITS OWN FUNCTION\*\*\*\*\*
92
What are 5 autonomic reflex centers(nuclei) found within the medulla?
1. Cardiovascular/vasomotor center 2. Swallowing center 3. Vomiting center 4. Coughing center 5. Sneezing center \*\*\*\*\*there is sensory input which activates these autonomic reflex centers leading to regulation of sympathetic and parasympathetic outflows of these centers\*\*\*\*
93
Where in the Medulla oblongata is the Chemoreceptor trigger zone located and what is it associated with?
CTZ is found in the 4th ventricle of the Medulla where CSF is located. It is highly associated with nausea and vomiting. Many receptors in the CTZ that respond to noxious stimuli which lead to nausea which can lead to vomiting. \*\*\*\*\*MANY ANTI-NAUSEA ANTI-VOMITING ARE AIMED AT CHEMORECPTORS FOUND HERE\*\*\*\*\*
94
What cranial nerves are associated with the Solitary nucleus?
CN# 9(glossopharyngeal) and CN# 10(vagus)
95
What cranial nerves are associated with the Nucleus ambiguus?
CN#9(glossopharyngeal), #10(vagus) and #11(spinal accessories)
96
As related to these two structures and cranial nerves, where is the location of important baroreceptors which are involved in the regulation of central BP?
CN#9 associated with baroreceptors in the carotids and CN#10 associated with baroreceptors in the aortic arch
97
As the sensory fibers of CN #9 and 10 approach the medulla they combine to form the _____ which terminates into the \_\_\_\_\_.
tractus solitarius; nucleus solitarius
98
Trace the nerve pathway of high blood pressure.
Sensory baroreceptors in the aortic arch(CN#10) and in the carotids(CN#9) are stimulated and excited---\>they send impulses up the fibers---\>the fibers join and form the tracts solitarius as they approach the nucleus solitarius---\>impulses are then sent to the Nucleus ambiguus(which is the CV control center)---\>alpha 2 receptors are excited which decreases sympathetic outflow and increases parasympathetic outflow(HR decreases, blood vessels dilate bringing BP down) BARORECPTOR RESPONSE REGULATES BP ON A SEC-BY-SEC BASIS!!!
99
Trace the nerve pathway of low blood pressure.
Sensory baroreceptors in the aortic arch(CN#10) and in the carotids(CN#9) are inhibited and not excited---\>they send less impulses up the fibers---\>the fibers join and form the tracts solitarius as they approach the nucleus solitarius---\>fewer impulses are then sent to the Nucleus ambiguus(which is the CV control center)---\>alpha 2 receptors are no longer excited so there is an increase in outflow of sympathetic and a decrease in parasympathetic outflow(HR increases, SV increases, strength of contraction increases) BARORECPTOR RESPONSE REGULATES BP ON A SEC-BY-SEC BASIS!!!
100
Which nerve transmits from baroreceptors in the aortic arch?
sensory fibers and CN X (Vagus)
101
Which nerve transmits from internal carotid baroreceptors?
sensory fibers and CN IX (Glossopharyngeal)
102
What are the 3 important neuro tracts that pass through the Pons?
1. Ascending(Sensory) tracts to higher brain centers 2. Descending(Motor) tracts from higher brain centers 3. Tracts connecting the Cerebrum to the Cerebellum
103
What 4 cranial nerves originate in the Pons?
5, 6, 7, 8
104
Besides the important tracts and the ordination of CN, what are 3 other important contents of the Pons?
1. Pneumotaxic respiratory center 2. Periaqueductal gray matter 3. part of the Locus ceruleus
105
What is the function of the Periaqueductal gray matter that is found in the Pons?
Concerned with modulation of PAIN TRANSMISSION. Lots of opioid receptors (Mu, Kappa, Delta) and many opioid peptides are found at the synapses within these areas. o Part of pain modulation pathways. Built in systems for decreasing the severity of pain transmissions
106
What is the function of the part of the Locus ceruleus that is located in the Pons?
major neurotransmitter is NE § One part of the brain that keeps us awake and alert when it is active. § When it is not active or inhibited, alertness decreases, and allows sleep to occur.
107
What 2 CN have their nuclei origin in the Midbrain?
3, 4
108
What are the 2 major divisions of the Midbrain?
Tectum(the roof) Tegmentum(the floor)
109
What is the name of the "four twin bodies" located in the Tectum of the Midbrain?
Corpora quadrigemina
110
The Corpora quadrigemina is further divided into 2 parts what are they?
Inferior colliculi Superior colliculi
111
What is the function of the Inferior colliculi located in the Corpora quadrigemina of the Tectum in the Midbrain?
neurons from inner ear synapse before transmitting impulses to primary auditory center Ø Sound impulses from the inner ear are transmitted thru the inferior colliculi before they get to the primary auditory center (where the sound is interpreted). \*sounds are not interpreted in the inferior colliculi, they just pass through on their way to primary auditory centers\*
112
What is the function of the Superior colliculi located in the Corpora quadrigemina of the Tectum in the Midbrain?
visual reflexes and visual tracking of moving objects; receive impulses from inferior colliculi, eyes, skin, and cerebrum -Involved in tracking images with your eyes -Input into the superior colliculi, from CN II, vision. \*IF, someone comes behind me and taps me on the back, you have to have an intact superior colliculi in order to turn. Ø EX. duck hunting\*
113
What 3 anatomical significant contents are in the Tegmentum of Midbrain?
Ascending tracts Red nuclei Substantia nigra
114
What is the function of the Ascending tracts that pass through the Tegmentum of the Midbrain?
MANY Ascending SENSORY tracts pass thru the floor of the midbrain (Tegmentum) to the higher brain centers
115
What is the path of the Ascending tracts that pass through the Tegmentum of the Midbrain?
SENSORY tracts start in the SPINAL CORD, then the MEDULLA, then the PONS, then they pass thru the floor of the MIDBRAIN (TEGMENTUM), on the way to the higher brain centers.
116
What is the function of the Red nuclei found in the Tegmentum of the Midbrain?
—origin of rubrospinal tract, an extrapyramidal motor tract (unconscious coordination of movements)
117
What is the function of the Substantia nigra located in the Tegmentum of the Midbrain?
—origin of nigrostriatal tract, which terminates on corpus striatum of cerebrum; part of basal nuclei
118
The Cerebral peduncles are also part of the Midbrain, what is their function?
descending tracts from cerebrum to spinal cord
119
Where is the Reticular Formation and Reticular Activating system located?
Clouds of gray matter distributed throughout the brainstem...receive impulses from nerves that innervate face (eyes, skin, ears, nose, etc.) § NO one place to point to, that shows the reticular formation. -Widely distributed throughout the brainstem and throughout the pons and probably the diencephalon.
120
The reticular activating system receives info from where?
visual auditory olfactory sensosomatic limbic(emotional) cerebral cortex(mental)
121
The ___ \_\_\_ is located in the RAS and it is related to the consciousness and sleep/wake cycle.
Locus ceruleus
122
What major neurotransmitter is believed to be involved in the sleep/wake/consciousness cycle of the RAS?
NE
123
How does NE affect the sleep/wake/consciousness cycle of the RAS?
-When the reticular formation is excited, that leads to a state of wakefulness, alertness and higher brain centers. -When inhibited, those excitatory sensations are no longer transmitted to higher brain centers, and that leads to a state of sleepfulness.
124
The sleep/wake/consciousness cycle is highly associated with the ___ \_\_\_ ___ located throughout the Midbrain.
Reticular Activating System
125
The major control of the respiratory cycle is in the ___ and the \_\_\_.
MEDULLA, PONS
126
What is the sequence events that occurs related to inspiration and the Medullary Inspiratory Center.
1. spontaneous active neurons(Meaning they spontaneously initiate and discharge action potentials) transmits impulses from MIC towards the spinal cord.
2. This collateral nerve synapses with the phrenic nerve which innervates the diaphragm.
3. when the diaphragm is ineervated by the phenic nerve, it contracts(becomes shorter) and pulls the lungs downward, increasing the longitudinal size of the thorax(lungs).
4. The other collateral continues on down the SC and synapses w/ intercostal nerves to the external intercostal muscles.
5. When the external intercostal muscles contract, they pull the ribs UP and OUT, which increases the anterior-posterior size of the thoracic and lungs. v It increases the size of the lungs, which increases the VOLUME in the lungs.
6. As intrapulmonary volume increases, the intrapulmonary pressure decreases. Intrapulmonary pressure is less than atmospheric pressure, AIR FOLLOWS THE PRESSURE GRADIENT. Air moves thru the tracheobronchial tree, into the alveoli.
7. AIR STOPS when the AIR EQUILIBRATES.
127
What is the other location and sequence of events occurring as the impulse is innervating the Phrenic/Intercostal nerve?
At the same time that impulses are being sent down to the phrenic n. and intercostal nerves; impulses are also being transmitted to the pontine pneumotaxic center [PPC]. 1. Once the PPC is excited, it sends an inhibiting impulses to the MIC. 2. Once inhibiting is stops sending impulses to the phrenic/intercostal nerves. 3. When the diaphragm is no longer excited, it relaxes, or domes back up. Pushes the lungs up. External intercostal muscles relax, and the ribs move DOWN and IN. 4. THIS decreases the size and volume of the lungs. Intrapulmonary pressure INCREASES and moves passively out of the tracheobronchial tree with the pressure gradient 5. When the pressures equilibrate, the movement of AIR stops.
128
What is the function of the Medullary Expiratory Center?
Normally expiration is a quiet, passive process that occurs when the signal to inspire is inhibited. § MEC is activated when the person needs to make a STRONG, ACTIVE expiration.
129
What is the sequence of events involved with the Medullary Expiratory Center?
1. When it does become excited, it transmits impulses to the INTERNAL INTERCOSTAL NERVES that innervate the INTERNAL INTERCOSTAL MUSCLES.
2. When the internal intercostal muscles are excited, that REALLY pulls the ribs DOWN and IN. If the ribs were really pulled DOWN and IN, the volume of the lungs decrease even more, the pressure increases even more for an ACTIVE outflow of air \*USUALLY does not come in to play except for active, forceful expiration.\*
130
What are the 6 reflexes/regulators involved with respiration?
1. Central chemoreceptors 2. Peripheral chemoreceptors 3. Stretch receptors 4. Proprioceptors 5. Receptors for touch, temperature and painful stimuli 6. Higher brain centers where our emotions reside
131
Where are the central chemoreceptors involved in the regulation of respiration located?
Medulla
132
How does the central chemoreceptors involved in the regulation of respiration function?
Primarily monitors pH of CSF § pH of CSF is determined (on an ongoing, breath-by-breath basis) by the amount of CO2 in the body fluids (CO2 diffuses very readily into blood and CSF). § As CO2 accumulates in CSF, and the pH of CSF drops down to the acid side, which is detected by the central chemoreceptors;. § Positive input to the respiratory centers to increase rate and depth of ventilations. § As rate and depth of ventilation increases, then the excess CO2 should be exhaled, bringing the pH of the CSF back into a normal range.
133
Where are the peripheral chemoreceptors located?
Located in the aortic arch and the bifurcation of the carotid.
134
How does the peripheral chemoreceptors involved in the regulation of respiration function?
o Primarily monitors pO2 at these locations. o Strategic location: blood has just returned to the lungs where it has been oxygenated, then ejected into the aorta, and then onto the carotids. o pO2 has to drop below ~60mmHg (some references say ~50) before there is any response from the peripheral chemoreceptors. o When they are excited, activated, from the low pO2; that has an excitatory affect on the respiratory centers, to INREASE rate and depth of respirations.
135
So what does the central chemoreceptors and the peripheral chemoreceptors monitor in relation to the regulation of respiration. Which is more involved in the minute-by-minutes regulation of respiration?
central chemoreceptors = CO2 peripheral chemoreceptors = pO2 \*For normal people, the CENTRAL chemoreceptors that has a much more minute-to-minute role in regulating respiratory cycles than the PERIPHERAL chemoreceptors.\*
136
What is another name for the stretch receptors that help regulate respiration?
Hering-Breuer reflex
137
Where are stretch receptors located?
Within lung tissue
138
What is the function of stretch receptors?
monitors the stretch of the lungs. Inhibits(negative) affect \* As the lungs expand, those stretch receptors are excited, and as they become excited they send an inhibitory impulse to the MIC to STOP INSPIRATION to prevent OVER-INFLATION of the lungs.\*
139
What is the function of the Proprioceptors?
involved in muscle tension, has a + affect on respiration. As tension INCREASES, that tends to have a positive impact on INREASING rate and depth of respiration
140
What affect does Receptors for touch, temperature and painful stimuli have on respiration?
Common response of pain = hyperventilation
141
What affect do the higher brain centers of the body have on respiration?
o We can consciously alter (to some extent) rate and depth of ventilations. o Fairly common response is change of rate and depth of ventilations.
142
What two nerves are collaterals from the MIC?
phrenic nerve intercostal nerve
143
What two structures do the collateral nerves from the MIC innervate?
phrenic nerve ---\> diaphragm intercostal nerve ---\> external intercostal muscle
144
When the external intercostal muscle is innervated what happens?
When the external intercostal muscles contract, they pull the ribs UP and OUT, which increases the anterior-posterior size of the thoracic and lungs.
145
When excited, what type of impulse does the Pontine Pneumotaxic Center send to the Medullary Insp. Center?
Which excites the PPC. When the PPC is excited, it then sends INHIBITORY impulses to the MIC.
146
What happens once the external intercostal muscles relax?
The ribs move down and in. THIS decreases the size and volume of the lungs. Intrapulmonary pressure INCREASES and moves passively out of the tracheobronchial tree with the pressure gradient. When the pressures equilibrate, the movement of AIR stops.
147
Normally expiration is a ___ and ___ process that occurs when the signal to inspire is inhibited.
quiet and passive
148
The Medullary Expiratory Center is activated when the person needs to make a ___ and ___ expiration.
strong and active
149
What are the 4 major parts of the Diencephalon?
1. Thalamus 2. Sub thalamus 3. Epi thalamus 4. Hypothalamus
150
Where in the brain does the Diencephalon sit?
BELOW the CORPUS CALLOSUM, right below the lateral ventricle
151
What is located between the 2 lobes of the Thalamus?
the 3rd ventricle
152
The _____ is the largest part of the Diencephalon.
Thalamus; its not as large as the 2 lateral ventricles
153
What is the primary function of the Thalamus?
The Thalamus is a Sensory Relay Center.
154
Define how the Thalamus functions as a Sensory Relay Center.
-Sensations ascend up the SC from various parts of the body. -at some point these sensations terminate in the Thalamus at their specify nuclei -from there they synapse with other pathways that relays the sensory information to the appropriate place in the brain \*\*\*most important role of Thalamus is once the sensation reaches it, it must know where in the higher brain to send the impulse\*\*\*\*\*
155
Almost all sensory input projects to the thalamus and then are projected to the _____ \_\_\_\_\_ for _____ \_\_\_\_\_.
cerebral cortex; conscious recognition
156
What fills the third ventricle which is located between the two lobes of the Thalamus?
CSF
157
What is the function of the Lateral geniculate bodies, and where are they located?
Located in the thalamus their function is associated with CN#2-Visual Impulses/Visual Pathways -CN II have their origin in rods and cones of the retina -When they enter the brain, CN II stops at the lateral geniculate bodies. - Then there are synapses w/ neurons that continue from the lateral geniculate body, back to primary visual centers and the occipital lobe.
158
What is the function of the Medial geniculate bodies, and where are they located?
Located in the thalamus § associated with CN VIII Auditory input § CN VIII fibers will terminate first in the medial geniculate bodies § Then synapse with neurons that transmit the auditory impulses to the primary auditory centers in the temporal lobes.
159
What is the function of the Ventral posterior and medial nuclei and where are they located?
Located in the thalamus There function is related to most other sensory input
160
What is the Sub Thalamus associated with?
Its part of the basal nuclei
161
What are the two major parts of the Epi Thalamus?
1. Haenular nucleus 2. Pineal body
162
What is the function of the Haenular nucleus part of the Epithalamus which is a part of the Diencephalon?
—part of limbic system; PLAYS A MAJOR ROLE in emotional and visceral responses to odors § EX: “ruptured gut in a trauma unit”
163
What is the function of the Pineal body which is a part of the Epithalamus which is a part of the Diencephalon?
body—secretes melatonin(MAJOR SOURCE OF MELATONIN); function unknown human, possibly related to onset of puberty § melatonin is secreted during times of darkness v suppressed by light also somehow is involved in the estrous cycle of animals
164
What are the two major parts of the Hypothalamus?
Anterior Pituitary and the Posterior Pituitary
165
What is the function of the Hypothalamus?
The function of the Hypothalamus is to regulate the Anterior and the Posterior Pituitary glands
166
If the Hypothalamus is abnormal, the _____ \_\_\_\_\_ will have abnormal function.
Pituitary Gland
167
What is the anatomical structure that connects the anterior pituitary gland to the hypothalamus?
The anatomical structure is the infundibulum
168
What is another name for the anterior pituitary gland?
adenohypothesis
169
What is the relationship between the hypothalamus and the anterior pituitary gland?
hormones from hypothalamus influence synthesis and secretion of hormones from anterior pituitary gland
170
What system connects the hypothalamus and the anterior pituitary gland that helps carry out their functions?
hypothalamohypophosial portal system
171
What is a portal system?
one that begins in a capillary network and ends in a capillary network and those two networks are connected by a vein
172
How does the Hypothalamohypophosial portal system work.
-Capillary networks from the hypothalamus join together to form a portal vein. -this vein travels down the Infundibulum and terminates in another capillary network in the anterior pituitary gland -through this portal system, hormones that are synthesized in the hypothalamus can be transmitted and bind to receptors located in the anterior pituitary gland to regulate hormone synthesis and secretion
173
SO, how are hormones from the anterior pituitary first regulated?
BY hormones from the hypothalamus. \*HORMONES (from hypothalamus)-hypothalamohypophosial portal system -anterior pituitary-regulate synthesis and secretion of specific hormones from the anterior pituitary\*
174
What is the corresponding anterior pituitary response to these hypothalamus hormones: Growth hormone releasing hormone
Growth hormone synthesis and secretion
175
What is the corresponding anterior pituitary response to these hypothalamus hormones: Growth hormone inhibiting hormone (somatostatin)
Inhibition of growth hormone synthesis and secretion
176
What is the corresponding anterior pituitary response to these hypothalamus hormones: Thyroid stimulating hormone releasing hormone
Thyroid stimulating hormone synthesis and secretion
177
What is the corresponding anterior pituitary response to these hypothalamus hormones: Adrenocorticotrophic hormone releasing hormone
ACTH synthesis and secretion
178
What is the corresponding anterior pituitary response to these hypothalamus hormones: Gonadotrophin releasing hormone
Follicle stimulating hormone and Luteinizing hormone synthesis and secretion
179
What is the corresponding anterior pituitary response to these hypothalamus hormones: Prolactin releasing hormone
Prolactin synthesis and secretion
180
What is the corresponding anterior pituitary response to these hypothalamus hormones: Prolactin inhibiting hormone
Inhibition of Prolactin synthesis and secretion
181
What connects the posterior pituitary gland to the hypothalamus?
hypothalamohypophosial tract
182
What is a tract?
bundle of axons and their myelin sheaths
183
What is the relationship between the hypothalamus and the posterior pituitary gland?
Nerve cell bodies located in the nuclei of the hypothalamus have axon bodies that extend down the hypothalamohypophosial tract and terminate in the posterior pituitary gland. \*hormones produced in the hypothalamus are transmitted through the axoplasm, then released from the posterior pituitary gland through action potentials\*
184
What are two hormones that are produced in the hypo plasm that is released by the posterior pituitary gland?
1. Anti diuretic hormone(ADH)---\>also known as vasopressin
2. Oxytocin
185
What is the function of ADH as related to its relationship with the hypothalamus and posterior pituitary gland?
Osmoreceptors in hypothalamus monitor osmolality of body fluids. Increased osmolality causes osmoreceptors to secrete ADH from posterior pituitary gland. Decreased osmolality causes osmoreceptors to inhibit secretion of ADH from posterior pituitary gland. ADH secretion causes water reabsorbtion in the renal tubules for hyper osmolality ADH inhibits water reabsorbtion in the renal tubes for hypo osmolality Body osmolality ~300
186
What is the function of oxytocin?
Oxytocin synthesized in hypothalamus and stored and secreted from posterior pituitary. Stimulus includes uterine contraction and stimulation of nipples. Oxytocin causes more uterine contraction and contraction of smooth muscles of mammary ducts for milk expression
187
What are the other autonomic centers that are located in the diencephalon?
o Autonomic centers-§ Neurons from higher brain centers synapse with autonomic centers in the hypothalamus. § Neurons from hypothalamus synapse with autonomic neurons in brainstem and spinal cord for control of heart rate, vasoconstriction/vasodilatation, urination, peristalsis, and others § Thus, hypothalamus coordinates emotional effects on physical responses (e.g., stress, anger, joy,sexual pleasure, etc.) o Swallowing center o Temperature regulation center: controls shivering and sweating o Hunger and satiety centers o Coordinates sleep-wake cycle with reticular activating system
188
Where is the Optic chasm located and what is it associated with?
It is located right below the hypothalamus and right above the pituitary gland It is associated with CN#2-the optic nerve
189
What happens if the pituitary gland becomes enlarged?
The pituitary gland which is surrounded on 3 sides by the bones of the Sellica turcia if it becomes enlarged has no other place to go but to push up on the optic chasm causing visual disturbances
190
What separates the right and left cerebrum hemispheres?
Longitudinal fissure
191
Where is the precentral gyrus located?
Precentral gyrus:located anteriorly to the Central sulcus, in the Frontal lobe.
v aka,PRIMARY MOTOR CORTEX
192
Where is the postcentral gyrus located?
Postcentral gyrus: located posteriorly to the Central sulcus, in the Parietal lobe.
v aka, the PRIMARY SENSORY CORTEX
193
Inward foldings of brain tissue is called?
Inward foldings = sulcus (singular), sulci (plural)
194
Outward foldings of brain tissue is called?
Gyrus (Gyri – plural): the upfoldings on the surface of the brain.
195
Where is the prefrontal lobe located?
The prefrontal lobe is located in the anterior part of the frontal lobe
196
What separates the frontal lobe from the parietal lobe?
Central sulcus
197
What separates the temporal lobe from rest of cerebrum?
Lateral fissure
198
How are the occipital lobe and the parietal lobe delineated?
THERE IS NOT ANY SPECIFIC ANATOMIC DEMARCATION THAT CLEARLY DELINEATES PARIETAL AND OCCIPITAL LOBES. Division is based more on function than it is on a specific anatomic demarcation
199
What is the function of the corpus collsum?
consists of axons of tracts, connect the R cerebrum hemisphere to the L. And L to R. So one side of the brain will know what’s going on with the other side.
200
What are the 3 parts of the Frontal lobe?
1. Prefrontal lobe
2. Pre motor area
3. Pre central gyrus(primary motor cortex)
201
What is the function of the prefrontal lobe of the frontal lobe?
Its the area of the brain that is responsible for PERSONALITY (creative talents, abstract reasoning talents, mathematical talents, and our “ARTSY-FARTSY talents.
\*If someone loses their function of the prefrontal lobes, they lose their personality and all the above\*
202
What are the characteristics of Left prefrontal dominant people?
L prefrontal lobe dominant:
v VERY organized
v VERY detailed oriented
v (usually) have high mathematical/ scientific reasoning abilities
v (most) people are R hand dominant
203
What are the charcteristics of Right prefrontal dominant people?
R prefrontal lobe dominant:
v (sometimes) drives L prefrontal lobe people crazy
v artsy-fartsy people
v (sometimes) rather disorganized and disheveled
v produce beautiful art, music, and creative designs
v (often) they are L handed
204
What is associated with the Premotor area of the frontal lobe?
Broca’s premotor speech area (left frontal lobe in most people)
205
What is the function of the Precentral gyrus(primary motor cortex)?
origin of many upper motor neurons for lateral and anterior corticospinal tracts for conscious muscular movements
\*MOTOR HOMUNCULUS:the larger the body part or area, the more muscles that have to carry out very carefully synchronized function\*
206
List the areas of the body from lateral to medial that are associated with the primary motor cortex and the motor humonculus.
![]()The upper body is in the lateral portions of the primary motor cortex, while the lower body is in the medial portions.
## Footnote
Lateral:Pharyanx, tongue, face, lips, jaw........hip,knee,ankle,toes:Medial
207
MUSCLES ON THE Right SIDE OF THE BODY ARE REGULATED BY
the?
Left primary motor cortex
208
Muscles on the left side of the body are regulated by the?
right primary motor cortex
209
What makes the Left:Right brain motor control possible?
THE DECUSSATION OF PYRAMID IN THE INTERIOR/ INFERIOR
MEDULLA
210
Almost all motor movements have their orgin in the ___ \_\_\_\_ \_\_\_\_.
primary motor cortex
211
What is the purpose of the primary motor cortex?
PURPOSE IS: pre-plan, presequence, pre-organize muscle movements
212
What originates in the primary motor cortex that is involved in mortor responses of the body?
The descending pathways that descend from the brain to the SC and then synapse with mucles throughout the body to bring about motor movements.
213
motor;sensory
214
What are the 3 main divisions of the parietal lobe?
1. Postcentral gyrus(sensory motor cortex)
2. Sensory association areas
3. Wernicke’s sensory speech area (left parietal lobe in most people)
\*Somatic Sensory Areas\*
215
What is the function of the Postcentral gyrus?
primary somatic(sensory) cortex -termination
of tertiary neurons for most sensory pathways (except visual and
auditory); conscious interpretation and localization of stimuli on surface
of body
216
What is the function of the Sensory Association Area?
Sensations are recived from the primary sensory cortex, Sensory association area prepare that sensation with previous experience
with the SAME SENSATION AND begins to determine the
relative significance of the sensation and what the brain and the body need to do about those sensations
217
What is the function of Wernicke’s area?
Wernicke’s sensory speech area (left parietal lobe in most people)—
interpretation of visual and auditory words
218
What is the primary sensory pathway?
ascending sensory tracts stops first at the thalamus
o then the thalamus directs those sensations to parts of the brain that
can best deal w/ that specific sensation
o sensations from various parts of the body (primarily the surface of the
body) are first transmitted here, and then again in the sensory association center, sensations are stored in the sensory association area o compares a given sensation with previous experience with that sensation
o determines the relative significance of the sensation
o and begins to decide what the brain needs to do, what the response needs to be, to a given sensation
219
How does the Sensory Association Area compare sensory info?
the more experience a person has with the experience, the more attention the brain pays to it; if a person has repetitive sensations, over and over and over, then the brain is going to pay more attention to the repetitive sensation than then other o sensations that are likely to be more detrimental to physiologic existence get more attention than
relatively minor, non-harmful sensations get
220
The Primary Sensory Cortex is also associated with the Sensory Humonculus. How is it organized from Lateral to Medial?
![]()
Lateral:intra abdominal, pharynx, tongue, lips, gum......hip, leg, foot, toes:Medial
221
What can be expected with people who have left sided strokes?
222
In what lobe is the Primary visual cortex?
Occipital lobe
223
Whre is the termination of the optic pathways?
Primary visual cortex
224
Where is the Visual association area and what is its fuction?
It lies adjacent to the primary visual cortex and its funciton is to compare visual imput with previous input and recognition, BUT NOT INTERPRETATION!
225
Where is the origin os the CN#2 the optic nerve?
Rods and cones of the retina
226
What intially happens when we see an image?
- The image is seen and tranmited via nerve fibers of CN#2 first to the thalamus
- Then from the thalamus to the primary visual cortex(the primary visual cortex is where the image is seen but not interpreted)
- the image is tranmitted from the primary visual cortex to the visual association area
- the visual association area compares that image with previous experiences with that image; the VAA starts making a decision about the significance of that image and how much attention the brain needs to pay to it
- depending on what the image is, the VAA often transmits it to other parts of the brain for final processing; for example if its a word it must go to Wernicke's area for actual interpretatino of the word
227
What occurs in the Primary Visual Cortex?
The image is seen but not interpreted
228
What happens in the Visual associaton area?
The image is compared with previous experiences and a decison is made if the brain needs to pay attention to it. If so the VAA transmits it to the part of the brain associated with it for final processing
229
What is the function of Wernicke's area of the brain?
Wwernicke's area is invovled in the the actual interpretation of the word that was recieved from the optic nerve to the Primary visual cortex
230
What is the fuction of Broca's area and where is it located?
Broca's area is located in the frontal lobe; it is the motor area for speaking
231
What is the sequence of events related to seeing a word, understanding that word and then speaking the word.
1. The image of the "WORD" is transmitted through the pupils to the rods and cones of the retina(the origin of CN#2-optic nerve\_
2. Action potential impulses transmit the image through CN#2 fibers and they terminate in the lateral geniculate bodies of the thalamus
3. In the thalamus, they synapse with other neurons that extend from the lateral geniculate bodies back to the primary visual cortex
4. In the primary visual cortex, the image of the "WORD" is seen only, no interpretation there!
5. The image is transmitted to the visual association which compares and recognizes the "WORD" from prevous associations.
6. The image is then transmitted to Wernicke's area for final interpretation of the "WORD"
7. The "WORD" is chosen in Wernicke's area and is then transmitted to Broaca's area(the motor area for speaking, in the frontal lobe).
8. Broca's area transmits the impulse to the primary motor cortex(according to the handout, the muscles involved with speaking ar on the lateral sides).
9. The primary motor cortex excites the nerve pathways---\>to the muscles that are involved with speaking
232
If a person has a dysfunctional Wernicke's area, that then are said to have? because of what? what is the S&S?
receptive aphasia;
d/t ischemia,hypoxia or stroke;
they cannot understand spoken or written words
233
Someone with a lesion in the Broca's area with a normal Wernickes area is said to have what?why?
they have expressive aphasia
they can understand spoken or written words they just cannot inititate the sequence of muscle activities involved with speaking that word
234
235
What is the sequence of events of repeating a word that you have heard spoken?
§ Sound waves enter the inner ear (CN VIII)
§ CN VIII terminates below the nucleus of thalamus
§ Synapses with pathways that transmit that sound, from the thalamus to the primary auditory cortex (in the temporal lobe)
§ Primary auditory cortex hears the sound but does not interpret the sound
§ Sound is then transmitted to the auditory association area, which associates that sound with previous experience with that sound, and begins to determine the relative significance of that sound
§ Depending on what the sound is, determines where that sound will transmit for final interpretation
§ IF the sound is perceived as a word, it is transmitted to Wernicke’s area
§ If you are going to speak the word, its chosen in the Wernicke’s area
§ Transmitted to Broca’s area, which transmits it to the primary motor cortex
236
Where is the primary auditory area located?
Temporal lobe(left temporal for most people)
\*termination of auditory pathways\*
237
What is the function of the auditory association area?
association of auditory input with previous input and recognition, but not interpretation of sounds
238
Where is the Basal Nuclei located and what is its function?
Located in many parts of the brain(intergrated with primary moter cortex and their pre-motor areas in the crebral hemispheres);
## Footnote
work together to regulate skeletal muscle movements operating at the UNCONSCIOUS LEVEL---\>as opposed to primary motor cortex which is conscious muscle movement
\*all components have to be functional in order for normal skeletal muscle movement to occur\*
239
Where is the nigrostriatal tract located and what is its function?
* nigrostriatal tract is located in the midbrain
* originates with the substantia nigra, where the nerve cell bodies are.
§ Extends upward into the cerebral hemispheres, and synapses on the caudate nucleus.
§ The neurotransmitter released at that synapse is DOPAMINE
240
The Substantia nigra is part of the _____ \_\_\_\_\_, it is located in the _____ and its fuction is?
* basal nuclei
* midbrain
* orgin of the nigrostrital tract with nerve cells that produce dopamine that synapse on the caudate nucleus
241
Where is the Subthalamic nuclei located?
diencephalon
242
What is the result of the release of the specific neurotransmitter of the nigrostriatal tract?
Dopamine binding with dopaminergic receptors is INHIBITORY to the output of the caudate nucles
243
Where is the Corpus striatum located, what are the 2 major divisions and what are their overall function?
1. cerebrum
2. Caudate nucleus & Lentiform nucleus
3. inhibition of unwanted muscular movements for controlled, coordinated movements
244
Where is the Caudate nucleus located?
in the Cerebrum; it is a part of the Corpus striatum
245
What three types of neurotransmitters affect the Caudate nucleus and what is the response?
1. Dopamine receptors-dopamine via the nigrostriatal tract---\>inhibits
2. Glutamate-binds with nicotinic receptors-from globus pallidus---\>excitatory
3. Acetylcholine-nicotinic receptors-from primary motor cortex---\>excitatiory
4. THERE NEEDS TO BE A VERY DELICATE BALANCE OF THESE NEUROTRANSMITTERS, TO REGULATE OUTPUT FROM ALL PARTS OF THE BASALNUCLEI, WHICH THEN REGULATES SKELETAL MUSCLE MOVEMENT, PRETTY MUCH AT THE UNCONSCIOUS LEVEL
246
What is an example of an inbalance in the Caudate nucleus?
Parkinson's Disease
247
What is the imbalance associated with Parkinson's disease?
* If there is a deficit of inhibitory dopamine at that synapse, excitatory glutamate and acetylcholine dominates at that synapse causing Parkinson disease
248
What are some S&S of Parkinson's and their progression?
Ø Resting (non-intentional) tremors: when a person is AT REST, they have a pill rolling movement of their fingers and thumbs, and an alternating supination/ pronation of their hands.
Ø In the early stages of Parkinson dz, those tremors may go away during intentional movement
Ø Person with Parkinson’s dz has very stout posture, gait is abnormal (slow, shuffling, unsteady gait), ability to speak is hindered, drooling d/t inability to swallow secretions well, handwriting becomes very small (micrographia)
249
What is an early non-surgical approach to treatment of Parkinson's?
replacement of dopamine with the help of a precursor like L-dope
\*Dopamine does not cross the BBB so you have to give Ldopa\*
250
What are the two components of the Lentiform nucleus of the Basal nuclei?
* Globus pallidus
* Putmen
251
What is the function of the Globus pallidus?
There’s a tract that has its origin in the globus pallidus that synapses on the caudate nucleus and that neurotransmitter is (probably, perhaps maybe, but not necessarily) glutamate
v Glutamate is always excitatory
252
Much of what is known about the limbic system is based
on abnormalities of various parts of the limbic system
253
What is the function of the Limbic system as related to emotion?
Controls to a great extent our emotions; how we emotional perceive our environment and how we emotionally respond to our environment
254
What is the function of the Limbic system as related to Pain?
What one person considers pain, another person may consider it pleasure and vice versa, we’ve all heard, “Whip me, beat me, show me you care!”
255
What is the function of the Limbic sytem as related to Motivation?
Motivation (to some extent) resides in various parts of the limbic system (also resides in the pre-frontal and many other parts of the brain)
256
What is the function of the Limbic system as related to Appetite?
Appetite: people who have limbic system lesions often have very perverse appetites, meaning those are the ones who eat red clay or chalk
257
What is the function of the Limbic system as related to Anger?
Anger (to some extent), people who have limbic system lesions usually don’t express anger; very docile people
258
What is the function of the Limbic system as related to Fear?
Fear: people with limbic system lesions often LOSE the fear response
259
What is the fuction of the Limbic system related to Sexual satisfaction
Sexual satisfaction: Much of what a person perceives as the object of their sexual expression/satisfaction is mediated through the limbic system. It has been proposed that the amygdala regulates choice of sexual expression/ satisfaction.
260
The Hippocampus is part of the Limbic system; what is its function?
Hippocampus (derived from the greek word that means seahorse): (plays a major) part of transfer of short-term memory to long-term memory and recall of long-term memories and their emotional associations
§ Major advance dementia, the hippocampus shrinks
§ They cannot store memory
§ Initially people can recall long term memory better than short-term
§ No TX for dementia
261
What happens in the dysfunction of the Hippocampus?
§ Major advance dementia, the hippocampus shrinks
§ They cannot store memory
§ Initially people can recall long term memory better than short-term
§ No TX for dementia
262
What is the function of the cerebellum?
"the little brain"
## Footnote
263
What is the anatomic location of the cerebellum?
located posterior and inferiorly to occipetal lobe
264
What is the anterior commissure?
* is a bundle of nerve fibers (white matter), connecting the two cerebral hemispheres across the midline
* involved in pain and pain sensation
265
What is the Cingulate gyri?
part of the limbic system it helps regulate emotion and pain
266
What are the results of abnormalities of the cerebellum?
Abnormalities of the cerebellum are also motor movement abnormalities, which are usually called INTENTION TREMORS
o aka, cerebellar intention tremor
o So when a person consciously starts to do something, that is when the tremors start
o If the cerebellar is dysfunctional, body parts are unknown in time and space
267
Proper function of the cerebellum is necessary for?
Necessary for unconscious control of smooth, coordinated muscular movements
268
What is the function of the Midbrain?
269
What is the function of the Reticular formation?
270
What is the function of the Cerebellum?
271
What is the sequence of events when we consciously decide to move a muscle?
1. the motor impulse travels downward from the primary motor cortex through the medulla towards the spinal cord
2. before reaching the spinal cord, it encounters a collateral that informs the cerebreum of the desired skeletal muscle movement
3. the main impulse reaches the spinal cord continues down the spinal cord until it synapses with a neuron and excits as a peripheal nerve
4. the peripheal nerve synapses with skeletal muscle fibers causing movement of that skeletal muscle fiber
5. the skeletal muscles move, that stretches golgi tendon bodies and muscle spindles
6. Which leads to transmission of proprioceptive sensations of the muscle that just moved (Type-A α)
7. Proprioceptive information is transmitted back to the SC and then eventually to the cerebellum NOW the cerebellum is receiving information about actual skeletal muscle movement So there cerebellum can now compare desired skeletal muscle movement with actual skeletal muscle movement
8. When the cerebellum receives information about desired as well as actual It sends information via the thalamus, back to the primary motor cortex So the brain will consciously know how much that body part is moving Cerebellum ALSO sends information via unconscious pathways, that is called extrapyramidal motor pathways, that regulates that neuron and the skeletal movement at the unconscious level
272
What is the function of the Diencephalon and its associated parts?
273
What is the function of the Cerebrum, basal nuclei and the limbic system?
274
What is the function of the Medulla oblongata?
275
What is the function of the Pons?
276
What is the difference between non-intentional tremors and intentional tremors?
non-intentional tremors is associated with Parkinson's while intentional tremors is associated with disorders of the cerebellum
277
What are the meninges?
These are the membranes that cover the brain. They anchor the brain and the CSF cushions the brain
278
What is the superior sagittal sinus?
infold of the dura matter that runs the entire length of the longitudinal fissure
279
What happens in the Dural Sinus?
Where CSF mixes with venous blood
280
MENINGES AROUND THE BRAIN ARE \_\_\_\_\_ W/ THE MENINGES AROUND THE SC
continous
281
What are the layers of the brain from the Skull inward(8)?
* SKULL
* PERIOSTEUM
* DURA MATER
* SUBDURAL SPACE
* ARACHNOID MATER
* SUBARACHNOID SPACE
* PIA MATER
* CEREBRUM
282
The Periosteum is the ?
(innermost part of the skull)
283
What is the function of the Dura mater?
(1st meningeal membrane)composed of two layers that around most of the brain are fused together into a single layer; to form the functional layer
284
What is the epidural space?
epidural space: the space between the dura mater and the
skull so if someone has an epidural bleed or epidural hematoma,
its between the dura mater and the skull
285
What is the subdural space?
Subdural space: usually a very thin filled fluid area.
§ normally not a real space but a potential space
286
What is the Arachnoid mater?
Arachnoid mater (2nd meningeal membrane
287
What are the characteristics of the Subarachnoid space?
* lots of small very fragile blood vessels at risk of bleeding related to HTN
* Bleeds here are very close to the brain
* a subarachnoid hemmoraghe is related to rupture of blood vessels in this space
* subarachnoid space around the brain is continous with subarachnoid space around the spinal cord
* has CSF in it
* little extension of arachnoid mater that is bound into that space
288
What is the function of the Pia mater?
(3rd or last meningeal membrane)directly attached to brain surface and not removable
289
When the dura mater gets down to the corpus callosum, it?
turns and goes up the other side.
290
What 3 structrues compose the Dural sinus?
1. Dural mater goes down the longitudinal fissure
2. Superior saggital sinus
3. Inferior saggital sinus
291
What is the Falx cerebri?
Falx cerebri: infolding of the dura mater
§ separates (in the midline) the R & L cerebral hemispheres
§ provides for the superior and inferior sagittal sinus
292
The superior and inferior saggital sinus is where what two things mix?
1. CSF
2. Venous blood
293
What is the Falx cerebelli?
Falx cerebelli: infolding of the dura mater between the two lobes of the
cerebellar hemispheres
294
What is the Tentorium(tent/roof) cerebelli?
Tentorium (tent/ roof) cerebelli: infolding of the dura mater between the
cerebral and cerebellar hemispheres
295
What is the Supratentorial structures?
Supratentorial: structure ABOVE the tentorium cerebelli
§ cerebral hemispheres and everything that is contained in
the cerebral hemispheres
296
What are the Infratentorial structures?
Infratentorial: structures BELOW the tentorium cerebelli
§ Cerebellar hemispheres
§ Midbrain: sitting right at the
tentorium
§ Pons
§ Medulla
297
What is the tentorial ring (notch) and what is its significance?
When the tentorium cerebelli infolds and the dural membrane from the other side meet, there is an opening there which allows structures to pass through going to higher brain centers.
\*Tentorial ring is often where hernation occur.\*
298
If a lesion is classified as being infratentorial or supratentorial; which do you suppose is more lethal?
* Usually lesions that are SUPRATENTORIAL, there is more room for it to expand before it causes increase ICP.
* INFRATENTORIAL IS WORSE: starts growing and there is little room for it to expand,
* and it can very quickly cause herniation of the medulla, down thru the foramen magnum and down to the SC.
* MEDULLA: CV and respiratory control centers; all of the ascending and descending pathways from the SC to the brain and brain to the SC
299
THE MENINGES AROUND THE BRAIN ARE CONTINUOUS W/ THE MENINGES AROUND THE SC W/ SOME DIFFERENCES: WHAT ARE THESE DIFFERENCES?
* the dura mater around the SC is only one layer
* dura mater around the SC is not attached to the bones of
the vertebral column, it is separated by the epidural space: between the dura mater and thevertebral column
* there are openings in the dura mater for nerve roots to
pass through
* the subdural space is underneath that
* then the arachnoid mater
* then subarachnoid space where CSF is present
* pia mater is attached directly to the SC itself; inseparable
from the SC
300
Formation, circulation and reabsorption of CSF needs to be a ___ \_\_\_ without interruption in order to maintain a normal volume and ICP
continuous cycle
301
Where is the majority of CSF synthesized?
The two lateral ventricles of the brain.
302
Where are the lateral ventricles locate?
located in the medial part if the cerebral hemispheres underneath
the corpus callosum
303
How is CSF formed?
* CSF is produced(synthesized) by ependymal cells that form (make-up) the choroid plexuses
* CSF is produced from plasma---\>although it is not the same composition as plasma and its not a plasma filtrate
304
once CSF has been formed by the choroid plexuses within the
two lateral ventricles, what happens to it?
, it moves thru the interventricular foramen into the third ventricle
305
What are some characteristics of the third ventricle(4)?
§ located in the diencephalon,in between to the two lobes of the thalamus
§ considerably smaller than the lateral ventricles
§ has a very small choroid plexus
§ synthesizes a very small percentage of CSF
306
After CSF leaves the third ventricle what happens to it?
from the third ventricle, theCSF passes thru the cerebralaqueduct into the fourth ventricle
307
What are some characteristics of the fourth ventricle(5)?
§ located posterior to the midbrain and anterior to the cerebellar hemispheres
§ smallest of the ventricles
§ very tiny choroid plexus
§ produces a very tiny percentage of CSF
§ continuous with the central canal of the SC
308
central canal of the SC continues all the way down to where the SC terminates, which is?
(lumbar vertebrae 1 or 2 depending on the individual)
309
What is the only NORMAL exit of CSF from the ventricular system?
3 small holes or openings call formina in the 4th ventricle
310
Once CSF exits the ventricular system via the forminas, where does it go?
Moves into the subarachnoid space around the brain and the subarachnoid space around the SC
311
What is the sequence of CSF formation and flow?
1. EPENDYMAL CELLS(FROM PLASMA TO CSF)
2. CHPOROID PLEXUSES
3. INTERVENTRICULAR FORAMEN
4. THIRD VENTRICLE
5. CEREBRAL AQUEDUCT
6. FORTH VENTRICLE
7. EXITS AT THE 3 FORMINA
8. TO THE BRAIN AND SC(ARACHNOID SPACE)
312
In order to maintain normal volume in the subarachnoid space and normal volume/ pressures in the ventricles of the brain; what must happen relation to CSF?
* Once the CSF moves into the subarachnoid space it has to be
* reabsorbed back into the blood
* The rate of formation of CSF by the choroid plexuses continues at about the same rate all the time
* So if its formed at the same rate, it needs to be reabsorbed back into the blood at about the same rate all the time
313
Where is the normal place that CSF exits the subarachnoid into the venous sinus where it mixes with venous blood?
ARACHNOID GRANULATIONS
~ A ONE-WAY STREET
\*the venous blood and CSF mixes together and primarily leaves the brain through the jugulars\*
314
Normal CSF pressure while patient laying supine?
50-100 cm H2O
315
Total volume of CSF in the average adult?
~150 ml
316
Total volume of CSF in all 4 ventricles?
~23 mls
## Footnote
§ it is so important that it is kept in that very narrow range of that volume
§ if that volume increases in the ventricles because its exit is occluded, that will increase the pressure
§ that pushes the brain tissue against the skull
317
Amount of CSF in subarachnoid space?
127 mg(avg adult)
318
How much CSF produced daily?
Daily production: 500 – 750 mL; continues despite rate of absorption and CSF pressure
319
Is the a sample of CSF or Serum/Blood?
total protein 15 - 45 mg/dl
CSF
320
Is the a sample of CSF or Serum/Blood?
Clear amber fluid
serum/blood
321
Is the a sample of CSF or Serum/Blood?
total protein 6 - 8.5 gm/dl
serum/blood
322
Is the a sample of CSF or Serum/Blood?
colorless/clear fluid
CSF
323
Is the a sample of CSF or Serum/Blood?
albumin 10 - 30 mg/dl
CSF
324
Is the a sample of CSF or Serum/Blood?
Chloride level 98 - 106
serum/blood
325
Is the a sample of CSF or Serum/Blood?
albumin 3.5 - 5 gm/dl
serum/blood
326
Is the a sample of CSF or Serum/Blood?
chloride 18 - 132
CSF
327
Is the a sample of CSF or Serum/Blood?
WBC 5K - 10K/microl
serum/blood
328
Is the a sample of CSF or Serum/Blood?
Mag level 0.78 - 1.26
CSF
329
Is the a sample of CSF or Serum/Blood?
WBC 0 - 5/microl
CSF
330
Is the a sample of CSF or Serum/Blood?
mag level 0.65 - 1.05
serum/blood
331
Is the a sample of CSF or Serum/Blood?
RBC of 0
CSF
332
Is the a sample of CSF or Serum/Blood?
K 4.0 - 5.1
serum/blood
333
Is the a sample of CSF or Serum/Blood?
RBC 4 - 6 X 10/microl
serum/blood
334
Is the a sample of CSF or Serum/Blood?
K 2.8 - 3.2
CSF
335
Is the a sample of CSF or Serum/Blood?
glucose of 70 - 110
serum/blood
336
Is the a sample of CSF or Serum/Blood?
Na 147 - 151
CSF
337
Is the a sample of CSF or Serum/Blood?
glucose of 50 - 75
CSF
338
Is the a sample of CSF or Serum/Blood?
Na 135 - 145
serum/blood
339
Bacterial or Viral Meningitis?
yellow/turbid appearance
marked increase in Polymorpho nuclear WBCs
Light increase or normal Lymphocytes
Protein slight increase or normal
Glucose decreased
Pyogenic bacterial meningitis
340
Bacterial or viral meningitis?
Clear appearance
slight increase or normal polymorphonuclear WBCs
marked increase in Lymphocytes
marked increase in protein
normal glucose
Viral meningitis
341
What are the two pathways of blood flow from the Right side?
R SIDE BRAIN CIRCULATION PATHWAY(via internal carotid patway):
* L VENTRICLE
* AORTIC VALVE
* ASCENDING AORTA
* R BRACHIOCEPHALIC ARTERY
* R COMMON CAROTID ARTERY
* INTERNAL CAROTID ARTERY
* FURTHER DIVISIONS
* LATERAL (PARIETAL AND FRONTAL LOBES) AND MEDIAL (FRONTAL LOBE)
R SIDE BRAIN CIRCULATION PATHWAY(via the subclavian pathway):
* L VENTRICLE
* AORTIC VALVE
* ASCENDING AORTA
* R BRACHIOCEPHALIC ARTERY
* R SUBCLAVIAN ARTERY
* VERTEBRAL ARTERY
* THROUGH THE FORAMINA OF THE TRANSVERSE PROCESSES OF THE CERVICAL VERTEBRAE
* FORAMEN MAGNUM
* TO THE BRAIN TISSUE
342
The first branch off the aorta to the R side is the?
brachiocephalic artery(innominate artery - R side only)
343
Right above the clavicle the brachiocephalic artery divides into the?
R subclavian artery and the R common carotid artery
344
At what anatomical point does the internal carotid enter the skull?
carotid canal
345
At what anatomical point does the vertebral arteries enter the skull?
foramen magnum
346
What is the circulation pathway of blood from the left ventricle to the brain from the left side?
* The common carotid branches directly off the aorta (NO brachiocephalic artery on the L side)
* Then pretty soon the L subclavian branches directly off the aorta
* The common carotid of the L continues up the neck
* Divides into the external carotid and internal carotid
o internal carotid enters thru the carotid canal and continue on up to the brain tissue
* From the L subclavian, the L vertebral artery passes thru the foramina of transverse processes of the cervical vertebrae
* continues on up to the base of the skull and enters thru the foramen magnum
* up to the brain tissue
SAME THING ON BOTH SIDES MINUS THE BRACHIOCEPHALIC ARTERY
347
Once blood flow reaches the brain via the internal carotid, what is the bloodflow pathway?
o Internal carotids divide into the middle cerebral artery and then very
quickly the anterior cerebral artery
o The middle cerebral arteries will perfuse: Right Lateral Parietal, Frontal & Temporal lobes & parts of diencephalon
o Anterior cerebral arteries will perfuse: Prefrontal & Medial Frontal & Parietal lobes
o Anterior communicating artery: connects the two anterior cerebral arteries
\*from this point the anterior communicating artery joins the right and left verterbral artery and blood flows into the Basilar Artery(perfuses Pons, cerebellum and parts of brainstem)\*
\*next the basilar artery flows into right and left Posterior cerebral arteries which perfuse right and left occipital, right and left temporal lobes and part of the diencephalon(right and left depending on which side is being perfused\*
348
Once bloodflow reaches the brain via the vertebral arteries what is the blood flow pathway?
o coming up on the anterior part of the brainstem
o one of the first divisions is the posterior inferior cerebellar artery(going to perfuse part of the cerebellar hemisphere)
o next is the anterior inferior cerebellar artery(going to perfuse the other part of the cerebellar hemisphere)
o then the TWO vertebral arteries diverge into the BASILAR artery; branching off of the basilar artery are the:
§ pontine arteries (bilaterally) perfuse parts of the pons, medulla, and the midbrain
§ superior cerebellar artery (bilaterally) perfuses the rest of the cerebellum
o the basilar artery then divides to form the posterior cerebral arteries (bilaterally)
§ the POSTERIOR cerebral arteries perfuse: the occipital lobes (laterally and medially) and almost all of the temporal lobe (inferiorly, laterally and medially) and parts of the diencephalon
349
Posterior communicating artery connect posterior cerebral to middle cerebral artery this is called?
The circle of Willis
350
What is the anatomical relationship to the brain and the Circle of Willis?
§ in the middle of the circle of willis, CN II passes thru there
§ just inferior to that in the sella turcica, is the pituitary
§ just above that is the hypothalamus of the diencephalon
§ the infundibulum that connects the hypothalamus to the pituitary, passes right thru there
§ THIS IS VERY VERY VERY IMPORTANT ANATOMIC RELATIONSHIPS
351
How does blood exits the brain?
BLOOD exits the brain:
o First into the venous sinuses
o then the venous sinuses empty into various veins, primarily empty into the internal jugulars
o then eventually into the superior vena cava
o back to the R atrium
352
What arteries make up the Circle of Willis?
1. R&L anterior cerebral arterys
2. posterior communicating artery
3. Anterior Communicationg artery
4. R&L posterior cerebral arterys
353
What does the Right anterior cerebral artery perfuse?
1. prefrontal
2. medial frontal
3. parietal lobes
354
What does the left anterior cerebral artery perfuse?
1. prefrontal
2. medial frontal
3. parietal lobes
355
What does the left post. cerebral artery perfuse?
1. left occipital lobe
2. left temporal lobes
3. part of the diencephalon
356
What does the right post cerebral artery perfuse?
1. right occipital lobe
2. right temporal lobe
3. parts of the diencephalon
357
What doe sthe right middle cerebral artery perfuse?
1. right lateral parietal lobes
2. right frontal lobes
3. right temporal lobes
4. parts of the dienephalon
358
What does the left middle cerebral artery perfuse?
1. leftlateral parietal lobes
2. left frontal lobes
3. left temporal lobes
4. left of the dienephalon
359
study brain flow chart!!!!
360
What is the normal contents of the intracranial space?
1. brain tissue
2. blood
3. CSF
361
What is the Lancaster modified Monroe-Kelly doctrine?
Increase in volume of one of the compartments (volumes) of the brain must be compensated for by a reciprocal decrease in the volume of one or more of the other compartments for the total brain volume to remain fixed and for the ICP to remain unchanged.
362
What are 2 places where CSF can be displaced?
o down central canal of the SC
o through arachnoid granulations into venous blood (if there is normal venous outflow)
363
In relation to ICP and intracranial volume, what is the normal pressure at the 0ml "normal volume" point?
10 - 15 mmHg
364
An increase in how many milimeters of volume of CSF starts making a difference in ICP?
* 4 mL of volume shows a significant change in pressure
* 5 mL of volume shows an even more significant change in pressure
* \>5 mL = pressure dramatically rises after that amount
* IC volume may tolerate an additional 3-4 mL of volume but beyond that, adding more volume, with each mL after that is an exponential increase in pressure that does not sustain life
365
366
Brain MUST have ___ & ___ blood flow to meet oxygen and glucose needs
continous and uninterrupted
367
What is the formula of autoregulation of pressures inpact upon brain perfusion?
CPP = MAP – ICP
368
What are the effects of pO2 and pCO2 on ICP?
High pCO2 causes brain tissue to vasodialte therby increasing ICP
Low pO2(50mmHg) causes brain tissue to vasodialte therby increasing ICP
369
What are the 4 herniation syndromes?
1. Cingulate
2. Central transtentorial
3. Uncal
4. Tonsillar
370
What are the characteristics of Cingulate Herniation syndrome?
**Cingulate: medially and above the corpus callosum**
§ cingulate gyrus herniates underneath the falx cerebri
§ the anterior cerebral artery on the side of the herniation is compressed
§ so if there is decreased blood flow thru the anterior cerebral artery these will become ischemic
§ PARTS OF THE BRAIN AFFECTED:
v prefrontal lateral
v prefrontal medial
v medial part of the frontal lobe
v medial parietal lobe
371
What are the characteristic of Central transtentorial Herniation syndrome?
**Central transtentorial:**
§ both cerebral hemispheres
§ diencephalon
§ midbrain
§ tentorial ring/notch
§ rapid loss of consciousness (because of the reticular activating system)
§ inability to follow movement lost
§ decerebrate or decorticate posturing
372
What are the characteristics of Uncal herniation syndrome?
**Uncal**
§ Little projection of the temporal lobe called the uncus,
§ herniates through the tentorial ring/ notch
§ usually s/t supratentorial lesions, increased ICP, about the tentorium
§ as an outcome, the pupil on the same side is dilated and fixed
§ compressing CN III on the same side as the herniation
§ rapid decrease of LOC, from the reticular activating fibers are cut-off
§ abnormal posturing, more decerebrate than decorticate
§ usually hyperventilation
§ **AND THE POSTERIOR CEREBRAL ARTERY ON THE SIDE OF HERNIATION IS OBSTRUCTED, FLOW IS CUT OFF**
**§ POSTERIOR CEREBRAL ARTERY, POSTERIOR CEREBRAL ARTERY,**
**§ POSTERIOR CEREBRAL ARTERY, POSTERIOR CEREBRAL ARTERY**
**§ PERFUSES: occipital lobe, inferior and lateral parts of the temporal lobe**
373
What are the characteristics of Tonsillar herniation syndrome?
**Tonsillar**
§ r/t to the tonsils of the cerebellar hemispheres
§ sitting right above the foramen magnum
§ is when the tonsils of the cerebellar hemispheres herniate down thru the foramen magnum
§ that cuts off connection between the SC and the brain; and the brain and the SC
§ literally the medulla herniates fown thru the foramen magnum into the SC
§ medulla: medullary CV system and respiratory centers
§ HENCE: usually rapid in progression and rapidly lethal, with very little successful interventions
