CH 15 Flashcards
Brain
1
Q
Organization of nervous tissue in CNS
A
- Nucleus
- Tract
2
Q
Nucleus
A
Group of neuron cell bodies in the CNS
3
Q
Tract
A
Group of axons traveling together in the CNS
4
Q
Types of tracts
A
- Commissural
- Association
- Projection
5
Q
Commissural
A
Tract where axons cross midline
6
Q
Corpus callosum
A
Largest (commisural) tract
7
Q
Association
A
Tract where axons do not cross the midline
8
Q
Projection
A
Tract where axons travel vertically
9
Q
Types of projections
A
- Ascending (sensory)
- Descending (motor)
10
Q
Organization of nervous tissue in PNS
A
- Ganglion
- Nerve
11
Q
Ganglion/ ganglia
A
Group of neuron cell bodies in the PNS
12
Q
Nerve
A
Group of axons traveling together in the PNS
13
Q
Which nerve is the largest?
A
Sciatic
14
Q
Gray matter
A
- Unmyelinated axons
- Dendrites
- Neuron cell bodies
15
Q
White matter
A
Myelinated axons
16
Q
Brain ventricles
A
Spaces inside tissue of brain; Cavities filled with cerebrospinal fluid (CSF)
17
Q
Cerebrospinal fluid is formed by the ___________ in each ventricle
A
choroid plexus
18
Q
Choroid plexus
A
Composed of a layer of ependymal cells and capillaries (smallest blood vessels) that lie in the pia mater; produces CSF in all ventricles
19
Q
How is CSF formed?
A
By leaked blood plasma across ependymal cells and capillaries
20
Q
What are the brain ventricles?
A
- Lateral
- Third
- Fourth
- Cerebral
21
Q
Lateral ventricle
A
In cerebral hemispheres
22
Q
The lateral ventricles are separated by the __________, a thin medial partition
A
septum pellucidum
23
Q
Third ventricle
A
In the diencephalon
24
Q
Fourth ventricle
A
Between the pons and cerebellum
25
Cerebral ventricle
Connects third and fourth ventricles; located in midbrain
26
What is the smallest brain ventricle?
Fourth
27
Blood is colored ________ in diagrams despite being red in real life
Arteries are colored __________ in diagrams
blue, red
28
Diagram that shows a view through the structure
Phantom diagram
29
Horn
Projection of a ventricle that goes into the lobe of the cerebrum
30
Aperture
Holes in the fourth ventricle where the CSF leaves
Lateral and medial
31
Meninges
Membranes which surround and protect the brain and spinal cord
32
Layers of the meninges
- Dura mater
- Arachnoid mater
- Pia mater
mater- mother
33
Dura mater
Meninge of the brain
Dense irregular CT
2 layers that wrap around the brain (1 wraps around the cord)
"Tough mother" - tough and fibrous
34
2 layers of the dura mater
- Periosteal layer
- Meningeal layer
35
Periosteal layer
Layer of the dura mater that is next to the periosteum of the skull
36
Meningeal layer
Layer of the dura mater that forms 3 septa between parts of the brain
37
Septa
Plural for septum
Flat partition separating 2 chambers
In terms of the brain's dura mater, these are membranous partitions that separate specific parts of the brain and provide additional stabilization and support to the entire brain
38
3 cranial dura septa
- Falx cerebri
- Falx cerebelli
- Tentorium cerebelli
39
Falx
Sickle shaped
40
Falx cerebri
Between cerebral hemispheres
Largest cranial dura septa
41
Falx cerebelli
Between cerebellar hemispheres
42
Tentorium cerebelli
Between cerebrum and cerebellum
43
Dural venous sinus
Large blood filled spaces between 2 layers of dura mater
44
Superior sagittal sinus
Dural venous sinus where CSF resorbs into blood
45
Arachnoid mater
Thin delicate tissue that is external to the pia mater
Composed of collagen and elastic fibers
46
The arachnoid mater forms ________ that extends into superior sagittal sinus
arachnoid villi
47
Pia mater
"Tender mother"
Areolar loose CT
Fused to the surface of the brain and spinal cord
Innermost brain meninge
48
Spaces between the meninges
- Epidural
- Subarachnoid
- Subdural
49
Sub
Deep to
50
Potential space
Not an actual space but can be if filled with substance (e.g. blood or fluid under trauma) between layers
51
Epidural space
Potential space between the bones of the brain and dura mater that contains veins and arteries that nourish the meninges and bones of the cranium
52
Subdural space
Potential space between the arachnoid mater and overlying dura mater
53
Subarachnoid space
Actual space immediately deep to the arachnoid mater
Between the arachnoid mater and underlying pia mater
54
Flow of CSF
1) CSF is produced by the choroid plexus in the ventricles
2) CSF flows from third ventricle through cerebral aqueduct into the fourth ventricle
3) CSF in fourth ventricle flows into subarachnoid space by passing through paired apertures or single median aperture, and into the central canal of the spinal cord
4) As CSF flows through the subarachnoid space, it removes waste products and provides buoyancy to support the brain
5) Excess CSF flows into the arachnoid villi, then drains into the dural venous sinuses. Pressure allows the CSF to be released into the blood without permitting any venous blood to enter the subarachnoid space. Greater pressure on the CSF in the subarachnoid space ensures that the CSF moves into the venous sinuses
choroid plexus
lateral ventricles
interventricular foramina
third ventricle
cerebral aqueduct
fourth ventricle
medial or lateral aperture
subarachnoid space
arachnoid villi
superior sagittal sinus
55
Interventricular foramina
Opening that allows communication of the lateral ventricles with the third ventricle
56
Cerebral aqueduct
Narrow canal that passes through the midbrain and connects the third and fourth ventricles
57
Central canal
Merges with the fourth ventricle at the inferior end
Part of the spinal cord
58
Cerebrum
- Location of conscious thought processes and origin of intellectual functions
- Contains a large number of neurons needed for complex analytical and integrative functions
- 2 large superior hemispheres
59
List actions that the cerebrum is responsible for
- Intelligence
- Reasoning
- Sensory perception
- Thought
- Memory
- Judgement
- Voluntary motor
- Visual
- Auditory
60
Fissure
Deep groove that separates gyri
61
Sulcus
Shallow groove that separates gyri
62
Gyri
Elevated ridges that the surface of the cerebrum folds into
Allows a greater amount of cortex to fit in the cranial cavity
63
Cerebral hemispheres are separated from each other by a ________________ that extends along the __________ plane
Longitudinal fissure, midsagittal
64
Cerebral hemisphere
Half of the cerebrum
65
Corpus callosum
Large, commissural tract connecting the two cerebral hemispheres
Provides main communication link between the hemispheres
66
Each cerebral hemisphere is divided into _____ anatomically and functionally distinct ________
5, lobes
67
Lobes of the brain
- Frontal
- Parietal
- Temporal
- Occipital
- Insula
68
All of the brain lobes are superficial except the ______
insula
69
Frontal lobe
- Lies deep to the frontal bone
- Forms the anterior part of the cerebral hemisphere
70
What is the frontal lobe involved with?
- Voluntary motor function
- Concentration
- Verbal communication
- Decision making
- Planning
- Personality
71
Central sulcus
Deep groove that separates the posterior end of the frontal lobe and the parietal lobe
72
Lateral sulcus
Deep groove that separates the inferior end of the frontal lobe and parietal lobe from the temporal lobe
73
Precentral gyrus
Anatomic feature of the frontal lobe
Mass of nervous tissue immediately interior to the central sulcus
74
Parietal lobe
- Forms superoposterior part of each hemisphere
- Underlies parietal bone
75
What is the parietal lobe involved with?
General sensory function
Receives and interprets sensse of the body (except special senses)
e.g. evaluating shape and texture, touch, pressure
76
The parietal lobe terminates anteriorly with the _________, laterally at the _________, and posteriorly at the ______________
central sulcus, lateral sulcus, parieto-occipital sulcus
77
Postcentral gyrus
Mass of nervous tissue immediately posterior to the central sulcus
78
Temporal lobe
- Located inferior to the lateral sulcus
- Underlying the temporal bone
79
The temporal lobe is involved with ______ and ______
hearing, smell
80
Occipital lobe
- Located in the posterior region of each hemisphere
- Underlying the occipital bone
- Processes incoming visual information
- Stores visual memories
81
Insula
- Deep to the lateral sulcus
- Involved with memory and interpretation of taste
- Also involved with empathy and emotional response, interoceptive awareness
82
Categories of functional areas
- Motor areas
- Sensory areas
- Association areas
83
Motor areas
Control voluntary motor function
84
Sensory areas
Provide conscious awareness of sensation
85
Association areas
Stores memories of past sensory experiences
Recognizes sensory input
86
Motor areas of the brain
- Primary motor area (somatic motor area)
- Motor speech area (Broca's area)
87
Primary motor area AKA somatic motor area
- Located in precentral gyrus
- Controls voluntary skeletal movement
Left primary motor cortex controls right side voluntary muscles and vice versa
88
Somato
Refers to body
89
Area is interchangeable with the term __________
cortex
90
Cortex
Outer layer of the cerebrum
91
Motor speech area AKA Broca's area
- Controls muscle movements necessary for vocalization
- Located in most individuals within the inferolateral portion of the left frontal lobe
- In left hemisphere only
92
Sensory areas of the brain
- Primary somatosensory cortex
- Primary visual cortex
- Primary auditory cortex
- Primary gustatory cortex
- Primary olfactory cortex
93
Primary somatosensory cortex
Receives general somatic sensory information from touch, pressure, pain, temperature receptors
94
The primary somatosensory cortex is located within the _________
postcentral gyrus
95
Primary visual cortex
Receives and processes incoming visual information
Located in occipital lobe
96
Primary auditory cortex
Receives and processes auditory information
Located in temporal lobe
97
Gustatory
Taste
98
Primary gustatory cortex
Processes taste information
Located in insula
99
Olfactory
Smell
100
Primary olfactory complex
Provides conscious awareness of smell
Located in temporal medial lobe
101
Association areas of the brain
- Premotor cortex (somatic motor association area)
- Somatosensory association area
- Auditory association area
- Visual association area
102
Premotor cortex AKA somatic motor association area
- Processes motor information and coordinates learned skilled motor activities
- Located in frontal lobe immediately anterior to precentral gyrus
- Memory of motor skills
103
Somatosensory association areas
- Integrates and interprets sensory information
- Stores memories of sensory information
- Located in parietal lobe immediately posterior to post central gyrus
104
Auditory association area
- Interprets characteristic sound
- Stores memories of sound
- Located within temporal lobe posteroinferior to the primary auditory cortex
105
Visual association area
- Processes visual information
- Stores memory of visual images
- Located in occipital lobe
106
Wernicke area
- Typically located only in left hemisphere where it overlaps parietal and temporal lobes
- Involved in recognizing, understanding, and comprehending spoken or written language
- Works with motor speech area for fluent communication
107
Cerebral/ basal nuclei/ basal ganglia
Paired, irregular masses of gray matter buried deep within the white matter of the basal region of the inferior to the floor of the lateral ventricle
Assists in coordinating skeletal muscle contraction
108
Basal nuclei components
- Caudate nucleus
- Lentiform nucleus
109
Caudate nucleus
- C-shaped with enlarged head and slim, arched tail that parallels the swinging curve of the lateral ventricle
- Neurons stimulate appropriate muscles to produce the pattern and rhythm of arm and leg muscles associated with walking
110
Lentiform nucleus
Compact, almost rounded mass composed of the putamen and globulus pallidus, masses of gray matter positioned between the insula and diencephalon
111
Putamen
Controls muscular movement at a subconscious level
112
Globus pallidus
Can excite or inhibit the anterior group of nuclei of the thalamus to regulate skeletal muscle tone
113
White matter of cerebrum
- Internal capsule
- Corona radiata
114
Internal capsule
Myelinated axons traveling between deep nuclei; Packed group of axons in projectile tracts passing to and from the cortex between cerebral nuclei
115
Corona radiata
Myelinated axons radiating out to different parts of the cortex
116
Diencephalon
- Epithalamus
- Thalamus
- Hypothalamus
117
Epithalamus
Forms roof of the diencephalon and covers the third ventricle
118
The posterior portion of the epithalamus houses the _________
pineal gland
119
Pineal gland
Secretes hormone melatonin
120
Melatonin
Hormone that regulates day-night cycles/ circadian rhythm
121
The thalamus is nicknamed _________
sensory relay station
122
Thalamus
- Large group of nuclei in diencephalon
- Receives, prioritizes, and sends all sensory information except smell to appropriate sensory cortex
123
Interthalamic adhesion/ Intermediate mass
Mass of gray matter that connects right and left lobes
124
What ventricle does the interthalamic adhesion travel through?
Third
125
Hypothalamus
- Anteroinferior region of diencephalon
- Infundibulum
126
Infundibulum
Connects hypothalamus to the pituitary gland
127
Pituitary gland
AKA master gland
- Sits in sella turcica in sphenoid bone
- Secretes 9 different hormones
128
Functions of hypothalamus
- Master controller of autonomic nervous system
- Master controller of endocrine system
Controls:
- Body temperature
- Certain emotions
- Sex drive
- Thirst and hunger
- Metabolism
- Water and electrolyte balance
129
Brain stem
- Mesencephalon (midbrain)
- Pons
- Medulla oblongata
130
Mesencephalon/ midbrain
Superior portion of brain stem
131
Mesencephalon/ midbrain components
- Tectal plates/ corpora quadrigemina
- Red nuclei
- Substantia nigra
- Cerebral penduncles
- Cerebral aqueduct
132
Tectal plates/ corpora quadrigemina
Nuclei that relay stations in processing pathways of visual and auditory sensations
133
Components of tectal plates
- Superior colliculi
- Inferior colliculi
134
Superior colliculi
Visual reflexes - visually track moving objects and control reflexes like turning eyes or head in response to visual stimuli
135
Inferior colliculi
Auditory reflexes - control turning of heads and eyes in unison as a response to an unexpected sound
136
Red nuclei
- Red color due to blood vessel density and iron pigmentation in neuronal cell bodies
- Motor coordination
- Integrates info from cerebrum and cerebellum
- Issues involuntary motor commands to erector spinae to maintain posture while standing, bending at waist, or walking
137
Substantia nigra
- Motor coordination
- Black color due to melanin pigmentation
- Produces neurotransmitter dopamine, which affects brain processes that control movement, emotional response, and ability to experience pleasure and pain
138
Cerebral penduncles
Projection motor tracts traveling through the midbrain
139
Superior cerebellar penduncle
- Connects cerebellum and midbrain
- Carries corrective feedback from cerebellum to motor cortex of cerebrum (via brainstem)
140
Pons
- Anterior bulge between the midbrain and medulla
- Composed of middle cerebellar peduncle and respiratory center
141
Middle cerebellar penduncle
Commissural motor tract that connects the pons to the cerebellum
Travels through pons
Carries motor plan from motor cortex to cerebellum
142
Respiratory center
Autonomic structure that regulates skeletal muscles of breathing and thus respiratory rate
- Pontine respiratory center (in pons)
- Medullary respiratory center
143
Medulla oblongata/ Medulla
Most inferior part of brainstem; Continuous with spinal cord
144
Inferior cerebellar penduncle
Connects the cerebellum to the medulla
Carries sensory feedback (proprioception) from body to cerebellum
145
Components of the medulla
- Cardiovascular center
- Respiratory center
- Pyramids
- Olives
- 4th ventricle
146
Cardiovascular center
Regulates heart rate and strength of contraction
147
Autonomic reflexes regulated by medulla
- Respiration
- Contraction
- Swallowing
- Sneezing
- Coughing
- Vomiting
Each has own nucleus
148
Pyramids
Longitudinal ridges on the medulla that house motor projection tracts
149
Olives
Bulges lateral to the pyramids, contain the inferior olivary nucleus
150
Inferior olivary nucleus
Large fold of gray matter that relays important sensory information and proprioceptive information to the cerebellum
151
Cerebellum
- Most important part of the brain for motor coordination and balance
- Muscle memory
- Adjusts skeletal muscle activity to maintain posture
- Receives proprioceptive (sensory) information from muscles and joints to regulate body position and sends it to the cerebrum
152
Components of the cerebellum
- Vermis
- Folia
- Arbor vitae
- Cerebellar penduncles
153
Vermis
Narrow band of cortex along the midline that connects the left and right cerebellar hemispheres
154
Folia
Folds on the surface that increase SA of the cerebellar cortex
155
Arbor vitae
White matter of cerebellum
156
Cerebellar penducles
- Superior, middle, inferior
- Connects brain and spinal cord
157
Voluntary movements
Primary motor cortex and basal nuclei in forebrain send impulses through the nuclei of the pons to the cerebellum
158
Assessment of voluntary movements
Proprioceptors in skeletal muscles and joints report degree of movement to the cerebellum
159
Integration and analysis of voluntary movement
Cerebellum compares planned movements (motor signals) against results of actual movements (sensory signals)
160
Corrective feedback of voluntary movement
Cerebellum sends impulses through the thalamus to the primary motor cortex and to motor nuclei in brainstem
161
Limbic system
- Group of nuclei and tracts located on medial border of cerebrum and diencephalon
- Responsible for experience of various emotions - processing and experiencing
- Involved with motivation, emotion, memory
- Affects memory formation by integrating past memories of physical sensations with emotional states
162
Components of limbic system
- Cingulate gyrus
- Fornix
- Hippocampus
- Amygdala/ amygdaloid nucleus
- Olfactory bulbs and tracts
- Mamillary bodies
163
Cingulate gyrus
- Only seen in sagittal cut
- Internal mass of cerebral cortex located within longitudinal fissure and superior to corpus callosum
- Surrounds diencephalon
- Receives input from other parts of limbic system
- Focuses attention on emotionally significant events and bring them to consciousness
164
Fornix
Thin tract of white matter that connects the hippocampus and other limbic structures
165
Hippocampus
- Nucleus that connects the diencephalon to the fornix
- Seahorse shaped
- Stores memory, forms long term memory
- Site of neurogenesis (formation of new neurons) for many animals
166
Mamillary body
Interconnect other parts of the limbic system, contribute to overall function
167
Amygdala/ amygdaloid nucleus/ amygdaloid body
- Connected to the hippocampus
- Involved with emotions, especially fear
- Stores and codes memories based on how a person perceives them (i.e. related to fear, extreme happiness or sadness)
168
Olfactory bulbs and tracts
Involved with smell
Particular odors can provoke certain emotions or be associated with certain memories
169
Reticular formation (RF)
Group of nuclei scattered throughout the brainstem
Gray matter projecting vertically through core of brain
170
Reticular formation components
- Reticular activating system (RAS)
- Reticulospinal tracts
171
The motor component of the reticular formation communicates with the ________ and is responsible for regulating ____________
spinal cord, muscle tone (especially when muscles are at rest)
Muscle tone is tension or resistance to movement
Also assists in autonomic motor functions like respiration, blood pressure, heart rate
172
Reticular activating system (RAS)
- Sensory component of the reticular formation
- Ascending tracts from RF to cerebral cortex
- Contains sensory axons that project to the cerebral cortex
- Processes auditory, visual, and touch stimuli to keep us mentally alert
173
Reticulospinal tracts
- Descending tracts from RF to spinal cord
- Maintain muscle tone
174
Consciousness
Awareness of sensation, voluntary control of motor activities, and activities necessary for higher mental processing
175
Alertness
Highest state of consciousness and cortical activity
Involves responsiveness, awareness of self, and well-orientated to person, place, and time
176
Cranial nerves
- 12 pairs
- Numbered by roman numerals according to position (I is most anterior)
- Names generally related to function
177
Olfactory nerve (CN I)
- Olfaction (smell)
- Sensory
- Conducts olfactory (smell) sensations to the brain
- Only type of nerve tissue to regenerate
178
Optic nerve (CN II)
- Vision
- Sensory
- Special sensory nerve of vision that is an outgrowth of the brain
- More appropriately called a brain tract
179
Oculomotor nerve (CN III)
Innervates upper eyelid muscle and four of six extrinsic eye muscles
Somatic motor:
- Supplies four extrinsic eye muscles to move eye (superior, medial, and inferior rectus, inferior oblique)
- Supplies levator palpabrae superioris to elevate eye
Parasympathetic/Autonomic motor:
- Innervates sphincter pupillae muscle in eye to make pupil constrict
- Contracts ciliary muscle to make lens of eye more rounded
180
Trochlear nerve (CN IV)
Innervates one extrinsic eye muscle (superior oblique)
Somatic motor:
- Innervates extrinsic, superior oblique eye muscle that loops through a pulley-shaped ligament
181
Trigeminal nerve (CN V)
Receives sensory impulses from face, oral cavity, nasal cavity, anterior scalp; innervates muscles of mastication
Sensory:
- Touch, temperature, pain
- Opthalmic V1: conducts sensory impulses from cornea, nose, forehead, anterior scalp, meninges
- Maxillary V2: conducts sensory impulses from nasal mucosa, palate, gums, meninges
- Mandibular V3: conducts sensory impulses from anterior two-third of tongue, meninges; skin of chin, lower jaw and teeth, one third from sensory axon of auricle of ear
Somatic motor:
- Innervates muscles of mastication (temporalis, masseter, lateral and medial pterygoids), mylohyoid, anterior belly of digastric, tensor tympani muscle, tensor veli palatani
182
Abducens nerve (CN VI)
Somatic motor:
- Innervates extrinsic lateral rectus muscle to abduct the eye
183
Facial nerve (CN VII)
Innervates muscles of facial expression, lacrimal (tear) gland, most salivary glands; conducts taste sensation from anterior two-third of tongue
Sensory:
- Taste from anterior 2/3rd of tongue
Somatic motor:
- 5 major motor branches (temporal, zygomatic, buccal, mandibular, cervical) innervate muscles of facial expression, posterior belly of digastric\, stylohyoid, stapedius
Parasympathetic motor
- Increases secretions of lacrimal gland of eye and submandibular and sublingual salivary glands
184
Vestibulocochlear nerve (CN VIII) AKA auditory or acoustic nerve
Sensory:
- Vestibular branch conducts impulses for equilibrium
- Cochlear branch conducts impulses for hearing
185
Glossopharyngeal nerve (CN IX)
Receives taste and sensation from posterior third of tongue; innervates one pharynx muscle and parotid salivary
Sensory:
- Sensation and touch to posterior third of tongue and most of pharynx
Somatic motor:
- Innervates stylopharyngeus (pharynx) muscle
Parasympathetic motor:
- Increases secretion of parotid salivary gland
186
Vagus nerve (CN X)
Innervates structures in the head and neck and in thoracic and abdominal cavities
Sensory:
- Visceral sensory information from heart, lungs, and most abdominal organs
- Sensory info from external acoustic meatus, ear drum, laryngopharynx, larynx
Somatic motor:
- Innervates most pharynx muscles and larynx muscle
Parasympathetic motor:
- Innervates visceral smooth muscle, cardiac muscle, glands of heart, lungs, larynx, trachea, most abdominal organs
187
Accessory nerve (CN XI)
Somatic motor:
- Innervates trapezius, sternocleidomastoid, some pharynx muscles
188
Hypoglossal nerve (CN XII)
Somatic motor:
- Innervates extrinsic and intrinsic tongue muscles
