Exam 1- Chapter 8 Flashcards
What is the CNS composed of?
- Brain
2. Spinal cord
Receives _____ from sensory neurons and _____ activity of motor neurons that innervate muscles and glands
- Input
2. Directs
What are 2 functions of association/interneurons?
- Integrate sensory information
2. Help direct the appropriate response to maintain homeostasis and respond to the environment.
***** How many neurons does the adult brain have?
100 billion
***** How much does the brain weigh?
1.5kg (3-3.5lbs)
***** How much % of the total body blood flow per minute does the brain receive?
15%
***** What is neurogenesis? Where have scientist demonstrated it?
- The formation of new brain cells from stem cells
2. Hippocampus
What is the cerebrum derived from?
Telencephalon
What is the largest portion of the brain? How much % of the brain is this structure?
- Cerebrum
2. 80%
What is the cerebrum responsible for?
Higher mental functions
What are the right and left cerebral hemispheres connected internally by?
Corpus Callosum
What is the outer region of the cerebrum composed of? What underlies it?
- 2-4mm of gray matter
2. White matter
Raised fold on cerebrum?
Gyri
Depressed grooves that separate the cerebrum?
Sulci
Deep sulci divide the cerebrum into how many lobes?
5
What are the lobes of the cerebrum?
- Frontal
- Parietal
- Temporal
- Occipital
- Insula
What are the frontal and parietal lobes separated by?
Central sulcus
Where is the percentral gyrus located? What is it responsible for?
- Frontal lobe
2. Motor control
Where is the postcentral gyrus located? What is it responsible for?
- Parietal lobe
2. Somatesthetic sensation (coming from receptors in the skin, muscles, tendons, and joints)
What is the temporal lobe generally known for?
Auditory centers
What is the occipital lobe generally known to be responsible for?
Vision and coordination of eye movements
What is the insula generally known to be responsible for?
- Encoding of memory
- Integration of sensory information with visceral responses; receives:
1. olfactory information
2. gustatory information
3. auditory information
4. pain information
Where are mirror neuron found?
Found in frontal and parietal lobes
What is the function of mirror neurons?
integrate sensory and motor neural activity
Mirror neurons are connected through the ______ to _____ centers in the brain.
- Insula
2. Emotional
What has been known to be implicated during autism?
Mirror neurons
Mirror neurons may be involved in the ability to learn what?
- Social Skills
2. Language
What are 5 methods utilized with brain imagery?
- X-ray computed tomography (CT)
- Positron emission tomography (PET)
- Magnetic resonance imaging (MRI)
- Functional magnetic resonance imaging (fMRI)
- Electroencephalogram (EEG)
How does X-ray computed tomography (CT) work?
looks at soft tissue absorption of X-rays
How does Positron emission tomography (PET) work?
radioactively labeled deoxyglucose injected into the blood; emits gamma rays in active tissues
What is Positron emission tomography (PET) used for?
- Used to monitor cancer
2. Used to study brain metabolism, drug distribution in the brain, and changes in blood flow following activity
How does Magnetic resonance imaging (MRI) work?
Protons in tissues are aligned by powerful magnets. The chemical composition of different tissues results in differences in proton alignment.
How can an MRI be amplified?
Can be amplified using MRI contrast agents injected before imaging
What does an MRI show clear definition between?
- Gray matter
- White matter
- CSF
How does Functional magnetic resonance imaging (fMRI) work?
visualizes increased neuronal activity in different brain regions indirectly by looking at blood flow
Release of what neurotransmitter increases vasodilation of blood vessels in the area when preforming an fMRI?
Glutamate
How does Electroencephalogram (EEG) work?
Electrodes on the scalp detect synaptic potentials produced by cell bodies and dendrites in the cerebral cortex.
What four different patterns/brain waves can be detected when preforming an EEG?
- Alpha waves
- Beta waves
- Theta waves
- Delta waves
What do alpha waves from an EEG indicate? Where are they seen most?
- Active/Relaxed brain
2. Frontal/Parietal lobes
What do beta waves from an EEG indicate? Where are they seen most?
- Visual stimulation/Mental activity
2. Frontal lobe
What do theta waves from an EEG indicate? Where are they seen most?
- During sleep (REM)
2. Occipital/Temporal lobes
What do delta waves from an EEG indicate? Where are they seen most?
- Also seen in sleep (Non-REM stages 3/4)
2. All over cerebrum
What are the two recognized categories of sleep?
- REM
2. Non-REM
In REM sleep, what occurs? What waves are seen here?
- Dreams
2. Theta Waves
What is Non-REM also referred to as?
Resting sleep
How many stages is Non-REM sleep divided into? What are these waves determined by?
- 4
2. Determined by EEG waves seen
In Non-REM sleep, what are stages 3 and 4 referred to? What type of brain waves are they characterized by?
- Slow-wave sleep
2. Characterized by delta waves
Describe the sleep cycle.
- When people first fall asleep: non-REM sleep and progress through the 4 stages
- Ascends back UP the 4 stages of non-REM sleep to REM sleep
How often does the sleep cycle often repeat? How many cycles do most people go through a night?
- Every 90 minutes
2. 5
When you are awaken naturally, what type of sleep were you usually in?
REM sleep
What are basal nuclei? Where are they located?
- Masses of gray matter
2. Deep in the white matter of the cerebrum
What is corpus striatum an example of?
Basal Nuclei
What is the corpus striatum composed of?
- Caudate nucleus
- Lentiform nucleus
1. Putamen
2. Globus pallidus
What is the Lentiform nucleus composed of?
- Putamem
2. Globus pallidus
What does contralateral mean?
Opposite side
Each side of the precentral gyrus controls movements on the ________ side of the body.
Contralateral (opposite)
Somatesthetic sensation from each side of the body projects to __________ of the postcentral gyrus
Contralateral sides
Communication between the 2 sides of the cerebrum occurs through the what?
Corpus Callosum
Describe the procedure that would occur for a patient with severe epilepsy?
Removal of the corpus callosum
The right hemisphere of the cerebrum is better at what?
- Visuospacial tasks:
1. recognizing faces
2. composing music
3. arranging blocks
4. reading maps
The left hemisphere of the cerebrum is better at what?
- Language
- speech
- writing
- calculations (analytical abilities)
Most of the knowledge of how the brain controls language has come from what?
people with speech problems called aphasias
Speech problems can be termed as?
aphasias
What two areas are identified as important in regards to language control?
- Broca’s area
2. Wernicke’s area
Where is the Broca’s area located?
Located in left inferior frontal gyrus
What does the Broca’s area control?
Motor aspects of speech
What are the symptoms of Broca’s aphasia?
slow, poorly articulated speech
there is no impairment in understanding
Although the Broca’s area controls motor aspects of speech, Broca’s aphasia DOES NOT affect what?
other actions of the: 1. tongue 2. lips 3. larynx are not affected; only the production of speech is affected
Where is the Wernicke’s area located?
Located in left superior temporal gyrus
What does the Wernicke’s area control?
Controls understanding of words
Information about written words is sent to the _______ from the ______.
- Wernicke’s area
2. Occipital lobe
What are the symptoms of Wernicke’s aphasia?
- Production of rapid speech with no meaning (called “word salad”)
- Language (spoken and written) comprehension is destroyed
As a whole, what is the limbic system?
Group of brain regions responsible for emotional drives
What is every area involved with the limbic system?
Cerebrum: 1. Cingulate gyrus 2. Amygdala 3. Hippocampus 4. Septal nuclei 5. Anterior insula Also from diencephalon: 7. Hypothalamus 8. Thalamus
What emotions are controlled by the limbic system?
- Aggression
- Fear
- Hunger/Satiety
- Sex drive
- Goal-directed behaviors
What part of the limbic system controls aggression?
areas in the amygdala and hypothalamus
What part of the limbic system controls fear?
amygdala and hypothalamus
What part of the limbic system controls hunger/satiety?
hypothalamus
What part of the limbic system controls sex drive?
the whole system
What part of the limbic system controls goal-directed behaviors?
hypothalamus and other regions
What are the 2 MAIN types of memory?
- Short-term
2. Long-term
What are the different types of long term memory?
- Non-declaritive (explicit*)
2. Declarative (implicit*)
What is included non-declarative long term memory?
includes memories of simple skills and conditioning
What is included declarative long term memory?
includes verbal memories
Amnesiacs are described by having impaired ________?
Declarative memory
What is the hippocampus responsible for?
- Critical for acquiring new memories
2. Consolidating short- into long-term memory
What type of memories is the amygdala crucial for?
Crucial for fear memories
Where does storage of memory occur?
Cerebral hemispheres
Higher order processing and planning occur in the ________.
Prefrontal cortex
Short-term memory involves a ______, when referring to synaptic changes.
recurrent circuit
When talking about the recurrent circuit of short-term memory, what do the neurons do?
neurons synapse on each other in a circle
What will result with the interruption of a recurrent circuit in short term memory? Is there a structural change?
Interruption of the circuit destroys the memory. There was no structural change.
Long-term memory requires a relatively ________ in neuron chemical structure and synapses.
permanent change
Describe Long-term potentiation (LTP) in the hippocampus.
- Synapses that are stimulated at a high frequency exhibit increased excitability
- In these synapses, glutamate is secreted by the presynaptic neuron
- The postsynaptic neuron has both AMPA and NMDA receptors for glutamate
- A retrograde messenger (likely NO) is released into the synapse, and the presynaptic axon is changed so that more glutamate can be released.
- Endocannabinoids may lift inhibition from GABA-releasing neurons on the synapse, further strengthening it.
(Post-synaptic neuron also receive input from other presynpatic neurons (release GABA))
In Long-term potentiation (LTP), GABA’s inihibiton is lessened by another _________ produced by the post-synaptic neuron. This retrograde messenger is?
- Retrograde messenger
2. Endocannabinoid
Stimulation by depolarization (by glutamate) is termed _________. This may also affect LTP.
depolariztion-induced suppression of inhibition
Where have neural stem cells been found in?
Hippocampus
In mice, what do physical activity and an enriched environment promote?
Neurogenesis
What can reduce neurogenesis?
Age and stress
What is the diencephalon?
Part of the forebrain that includes:
- Epithalamus
- Thalamus
- Hypothalamus
- Part of the pituitary gland
What are 2 functions of the thalamus?
- Relay center through which most sensory information is passed to the cerebrum
- Promotes a state of arousal from sleep and alertness
What is contained within the epithalamus? Where exactly is this structure? What does it produce?
- Choroid Plexus
2. Pineal gland
Where exactly is the Choroid Plexus? What does it produce?
- Over the third ventricle
2. CSF
What hormone does the pineal gland produce? What is that hormone involved in?
- Melatonin
2. Helps regulate circadian rhythms
What is the main general description of the function of the hypothalamus?
Very important for maintaining homeostasis and regulating the autonomic system
What centers are contained within the hypothalamus?
- Hunger/satiety and thirst
- Regulation of body temperature
- Regulation of sleep and wakefulness
- Sexual arousal and performance
- Emotions of fear, anger, pain, and pleasure
- Control of the endocrine system
Suprachiasmatic nuclei (SCN) contain what, and how many? How often do those cells oscillate?
- 20,000 clock cells
2. Every 24 hours
Suprachiasmatic nuclei (SCN) are entrained by information about day length via what?
Tracts from cells in the retina
What do Suprachiasmatic nuclei (SCN) control?
Controls the secretion of melatonin from the pineal gland
What is the midbrain also called?
Mesencephalon
What is within the midbrain?
- Superior colliculi
- Inferior colliculi
- Cerebral peduncles
- Red nucleus
- Substantia nigra
What are the superior colliculi involved in?
visual reflexes
What are the inferior colliculi involved in?
auditory reflexes
What is the function of the red nucleus?
- Connects the cerebrum and cerebellum
2. Involved in motor coordination
What is the function of the substantia nigra? What system is it part of?
- Important part of the motor circuit
2. Part of the dopaminergic nigrostriatal system
Ventral tegmental area (VTA) is part of what?
Part of the dopaminergic mesolimbic system that sends neurons to the limbic system and nucleus accumbens in the forebrain
The _____ is involved in the behavioral reward system and has been implicated in addiction and psychiatric disturbances.
Ventral tegmental area (VTA)
What is the hindbrain also called?
rhombencephalon
What is the hindbrain/rhombencephalon composed of?
- Metencephalon
2. Myelencephalon
What is the Metencephalon composed of?
- Pons
2. Cerebellum
What is the myelencephalon composed of?
medullla oblongata
The pons houses sensory and motor tracts heading ___/___ the _______.
- To/From
2. Spinal cord
What 3 cranial nerves arise from the pons?
- Trigeminal
- Abducens
- Facial
- Vestibulocochlear nerves
What two respiratory control centers are found within the pons?
- Apneustic
2. Pneumotaxic
Where does the cerebellum receive input from?
proprioceptors in joints, tendons, and muscles
What 2 structures does the cerebellum work with? What is their goal?
- Basal nuclei and motor cortex
2. Coordinate movement
Describe the tract the fibers of the cerebellum take.
Cerebellum —-> red nucleus—–> thalamus ——> motor cortex
The cerebellum influences motor coordination through inhibition of what?
inhibition on the motor cortex
What exactly is the cerebellum needed for?
- Motor learning
2. Proper timing and force required to move limbs in a specific task
All ascending and descending tracts between the brain and spinal cord pass through the __________.
Medulla Oblongata
Tracts within the medulla oblongata cross sides in the ____.
Pyramids
What cranial nerves come off the medulla oblongata?
Cranial nerves VIII, IX, X, XI, and XII (8-12)
The medulla oblongata contains the nuclei required for what? What are these known as?
- Regulation of breathing and cardiovascular response
2. Vital centers
What does the vasomotor center of the medulla oblongata control?
controls blood vessel diameter
What does the cardiac center of the medulla oblongata control?
heart rate
What does the rhythmicity center of the medulla oblongata do?
helps areas in the pons control breathing
To fall asleep what must we tune out?
Sensory Stimuli
When we awake up, what are we now alert to, that we weren’t when we were sleeping?
Sensory Stimuli
To fall asleep, we must tune out sensory stimuli. When awake, we are alert to sensory stimuli. What does this depend on?
Activation and inhibition of the reticular activating system (RAS)
What is included within the RAS?
- Pons
2. Reticular formation of the midbrain
Spinal cord has outer ____ layer, and inner _______.
- White matter
2. Gray matter
The gray matter of the spinal cord contains what?
- Left and right dorsal horn
2. Left and right ventral horn.
What is the white matter of the spinal cord composed of?
ascending and descending fiber tracts
The white matter is arranged into what? How many? What are they called?
- Columns
- 6
- Funiculi
Ascending tracts are given the prefix _____ with a suffix that indicates___________________.
- Spino-
2. The brain region it synapses on
Descending tracts are given the suffix_______, and the prefix indicates ______________.
- -spinal,
2. The brain region they came from
What do ascending tracts do?
Convey sensory information from receptors in the skin, muscles, joints, and organs
Where may crossover of information (contralateral) of ascending tracts occur?
may occur in the spinal cord or in the medulla
What are the two major groups of the descending tracts?
- Corticospinal (Pyramidal) Tracts
2. Extrapyramidal Tracts
How do Corticospinal (Pyramidal) Tracts work?
descend directly without synaptic interruption from the cerebral cortex to the spinal cord
Cell bodies of the neurons involved in Corticospinal (Pyramidal) Tracts are located where?
- Precentral gyrus
2. Superior frontal gyrus
Where do most (describe the %) Corticospinal (Pyramidal) Tracts cross sides in? What do they further descend as?
- (80%) medulla pyramids
2. Descend as lateral corticospinal tracts
The Corticospinal (Pyramidal) Tracts that do not cross sides at the medulla pyramids cross where? What do they further descend as?
- Spinal cord
2. Anterior corticospinal tracts
How do Extrapyramidal Tracts work?
originate in the brain stem and are controlled by the motor circuits of the corpus striatum, substantia nigra, and thalamus
Symptoms of parkinson disease reveal the importance of one of the descending tracts for initiating body movements, maintaining posture, and controlling facial expression? Which one?
Extrapyramidal Tracts
Are cranial nerves part of the CNS or PNS?
PNS
Where do cranial nerves directly arise from?
nuclei in the brain
How many paris of cranial nerves are there?
12
Most cranial nerves are ______ nerves.
Mixed
The cranial nerves associated with vision, olfaction, and hearing are ______ only.
Sensory
Cell bodies of the cranial nerves associated with vision, olfaction, and hearing located where?
not in the brain but in ganglia located near the sensory organ
Are spinal nerves part of the CNS or PNS?
PNS
Where do spinal nerves directly arise from?
Spinal Cord
How many paris of spinal nerves are there? Break them down and give the number of each region.
1. 31
2.
1. Cervical (8)
2. Thoracic (12)
3. Lumbar (5)
4. Sacral (5)
5. Coccygeal (1)All spinal nerves are ____ nerves.
Mixed
Where do spinal nerves separate? Into what?
- Near spinal cord
- Dorsal root (sensory)
- Ventral root (motor)
The dorsal root of the spinal cord contains what nerve fibers?
Sensory nerve fibers
The ventral root of the spinal cord contains what nerve fibers?
Motor nerve fibers
Where are sensory neuron bodies housed?
Dorsal root ganglion
