Chapter 13: Brain and Cranial Nerves Flashcards
The cerebrum is the
largest region with 2 hemispheres and five lobes per hemisphere
4 major brain regions
1- cerebrum
2- diencephalon
3- brainstem
4- cerebellum
Diencephalon consists of
epithalamus, thalamus, and hypothalamus
Brainstem consists of
midbrain, pons, medulla oblongata
Cerebellum is the
second largest region
Gyri
ridges
Sulci
depressions between ridges
Fissures
deep sulci
The Cerebrum is the center of
- intelligence and reasoning
- thought, memory, and judgment
- voluntary control of skeletal muscle
- conscious perception of senses
Longitudinal fissure
deep cleft separating hemispheres
Corpus callosum
largest tract providing connection between the two hemispheres
Cerebral lateralization
each hemisphere interacts with the opposite side of the body
Left hemisphere
- categorical hemisphere
- controls the right side
- language and speech
- “seat of logic”
Right hemisphere
- representational hemisphere
- controls left side
- visuospatial relationships
- “seat of emotions”
5 lobes of the brain
1- frontal
2- parietal
3- temporal
4- occipital
5- insula
Functions of the frontal lobe
motor control, concentration, verbal communication, decision-making, planning, and personality
Function of the parietal lobes
general sensory functions
Functions of the temporal lobes
hearing and smell
Functions of the occipital lobe
vision and visual memories
Functions of the Insula
memory and sense of taste
3 motor areas
1- primary motor cortex
2- motor speech area
3- frontal eye field
Primary motor cortex (somatic motor area)
located in the precentral gyrus; initiates voluntary skeletal muscle control
Motor speech area (Broca area)
located in the inferolateral portion of the left frontal lobe; controls movement for vocalization
Frontal eye field
located on superior surface of middle frontal gyrus; regulates eye movements needed for reading and binocular vision
The 5 sensory areas
1- primary somatosensory cortex
2- primary visual cortex
3- primary auditory cortex
4- primary olfactory cortex
5- primary gustatory cortex
Primary somatosensory cortex
receives somatic sensory information
Primary visual cortex
receives, processes, and stores visual information
Primary auditory cortex
receives, processes, and stores auditory information
Primary olfactory cortex
receives, processes, and stores odor information.
Primary gustatory cortex
receives, processes, and stores taste information
The 4 association areas
1- premotor cortex (somatic motor association area)
2- somatosensory association area
3- visual association area
4- auditory association area
Premotor cortex (somatic motor association area)
coordinates learned, skilled activities; located anterior to premotor cortex
Somatosensory association area
integrates touch information allowing us to identify objects by feel; immediately posterior to postcentral gyrus
Visual association area
integrates and interprets color, and form, to allow identification/recognition of things (ex. faces); located surrounding the primary visual cortex
Auditory association area
integrates and interprets sounds; located in the temporal lobe
Wernicke’s area
involved in language and comprehension; located in the left hemisphere
2 functional brain regions
1- wernicke area
2- gnostic area
Gnostic area
integrates somatosensory, visual, and auditory information of association areas; composed of regions of parietal, occipital, and temporal lobes
Proprioception
aware of the body
Association areas
process and interpret data and/or coordinate motor response
Epilepsy
neurological disorder where neurons transmit action potentials too frequently and rapidly
Cerebrovascular accident (CVA or stroke)
due to blocked arterial blood vessels or hemorrhage; reduced blood supply to part of brain; affects opposite side of body
Diencephalon
provides the relay and switching centers for:
- sensory and motor pathways
- control of visceral activities
Epithalamus
forms the posterior part of the roof of the diencephalon, covers the third ventricle; consists of the pineal gland and habenular nuclei
Pineal gland
helps regulate day-night cycles, circadian rhythm; endocrine gland secreting melatonin
Habenular nuclei
help relay signals from limbic system to midbrain; involved in visceral and emotional responses to odors
Thalamus
process and project somatosensory information to the somatosensory cortex; receives signals from all conscious senses except olfaction; filters out signals that are distracting from the subject of attention
Functions of the hypothalamus
1- control of the autonomic nervous system
2- control of the endocrine system
3- regulation of body temperature
4- food intake
5- water intake
6- sleep-wake rhythm
7- emotional behavior
Infundibulum
stalk of the pituitary that extends from hypothalamus
Where is the hypothalamus found within the diencephalon
anterior inferior region of the diencephalon
Cerebral palsy
impairment of skeletal muscle results from damage to the infant’s brain before, during, or right after birth
Parkinson’s disease
affects muscle movement and balance; caused by decreased dopamine production in substantia nigra
Substantia nigra
a cluster of cells with a black appearance due to melanin; houses neurons producing dopamine; its degeneration causes Parkinson’s disease
Brainstem
connects the cerebrum, diencephalon, and cerebellum to the spinal cord; contains ascending and descending tracts; contains autonomic nuclei, nuclei of cranial nerves, and reflex centers
The brainstem includes 3 regions
1- midbrain
2- pons
3- medulla oblongata
Midbrain
components:
- substantia nigra: houses neurons producing dopamine (involved in movement, emotions, pleasure, and pain response
- tectum: contains four mounds making tectal plate; 2 superior colliculi and 2 inferior colliculi
Superior colliculi
control visual reflexes and tracking
Inferior colliculi
control auditory reflexes
Pons
includes sensory and motor tracts connecting the brain to the spinal cord; middle cerebellar peduncles
Pontine respiratory center
helps regulate skeletal muscles of breathing
Medulla oblongata
inferior portion of brainstem; continuous with spinal cord inferiorly; houses corticospinal tracts for motor control that connects to the cerebellum
Cardiovascular center is composed of
- cardiac center
- vasomotor center
Cardiac center
regulates the heart’s output
Vasomotor center
regulates blood vessel diameter; influences blood pressure
Medullary respiratory center
controls breathing rate
Cerebellum
produces fine control over muscular actions; stores memories of movement
Functions of the cerebellum
- stores memories of previously learned movements
- regulates activity along voluntary and involuntary motor paths
- adjusts movements initiated by the cerebrum, ensuring smoothness
- helps maintain equilibrium and posture
Effects of alcohol and drugs on the cerebellum
- disturbance of gait
- loss of balance and posture
- inability to detect proprioceptive information
Limbic system
“the emotional brain”; is composed of multiple cerebral and diencephalic structures that form a ring around the diencephalon
What is the main function of the limbic system?
collectively process and experience emotions
Structures found within the limbic system
- cingulate gyrus
- amygdaloid body
- olfactory bulbs, olfactory tracts, and olfactory cortex
- hippocampus
- mammillary bodies
Cingulate gyrus
regulates emotions and pain
Amygdaloid body
involved in many aspects of emotion and emotional memory, especially fear
Olfactory bulbs/olfactory tracts/olfactory cortex
process odors that can provoke emotions
Hippocampus
helps form long-term memories (neurogenesis)
Mammillary bodies
interconnect with other parts of the limbic system and memories that you have seen something before (deja vu)
Reticular formation
loosely organized gray matter of the brainstem that receives and processes various types of input from sensory receptors
Motor components
regulate muscle tone via spinal cord connections and assist in autonomic functions through brainstem connections
Components of reticular formation
- motor components
- sensory components
Sensory components
processes sensory information sends signals to the cortex to bring about alertness which helps bring about awareness, which is necessary for the highest states of consciousness
Reticular activating system (RAS)
the sensory component of the reticular formation, responsible for alerting the cerebrum to incoming sensory information
Identify the brain area in which cognition occurs
cerebral cortex (cortex of cerebrum)
Fainting
brief loss of consciousness
Stupor
arousable only to extreme stimuli
Coma
deep and profound unconsciousness; nonresponsive
Persistent vegetative state
lack of thought and awareness but noncognitive brain functions continue
Electroencephalogram (EEG)
diagnostic test where electrical activity of the brain is measured
Consciousness
it includes awareness of sensation and voluntary motor activities
Higher-order mental functions
- include learning, memory, and reasoning
- occur within the cortex of cerebrum
- involve multiple brain regions
- both conscious and subconscious processing involved
Types of memory
- sensory memory
- short-term memory (STM)
- long-term memory (LTM)
Sensory memory
associations based on sensory input that last for seconds
Short-term memory
limited capacity and brief duration
Long-term memory
can be encoded from short-term memory if the information is repeated; may exist indefinitely, but can be lost if not retrieved occasionally
Secondary LTM
fades with time
Tertiary LTM
things stored in memory years ago that are with you for a life time
Conversion of short-term memory to long-term memory
- requires proper functioning of the amygdaloid body and hippocampus
- hippocampus required for the formation of short-term memory
Name the 2 regions of the limbic system involved in the conversion of STM to LTM
the amygdala and the hippocampus
Explain the interactions of the prefrontal cortex and the limbic system in the expression of emotions
emotions are interpreted by the limbic system, but expression is controlled by the prefrontal cortex
REM sleep
active dreaming occurs; need REM to feel “rested”
Deep sleep
the entire body relaxes; all metabolic functions are significantly reduced
The cranial meninges in superior to inferior order
- dura mater
- arachnoid mater
- pia mater
Dura mater
strongest of the meninges and made of dense irregular connective tissue
Arachnoid mater
is a delicate web of collagen and elastic fibers
Pia mater
innermost of the cranial meninges and made of areolar connective tissue
Ventricles
cavities or expansions within the brain that are derived from the neural canal
Cerebrospinal fluid (CSF)
a clear liquid produced by the choroid plexus that circulates within the ventricles and bathes the exposed surfaces of the CNS
Cerebrospinal fluid functions
- buoyancy
- protection
- environmental stability
Choroid plexus
a region of specialized tissue in each ventricle
Cerebral cortex
the surface layer of gray matter of the cerebrum
Frontal lobe functional areas
- primary motor cortex
- premotor cortex
- frontal eye field
- motor speech area
- prefrontal cortex
Insula functional area
primary gustatory cortex
Parietal lobe functional areas
- primary somatosensory cortex
- somatosensory association area
Occipital lobe functional areas
- primary visual cortex
- visual association area
Temporal lobe functional areas
- primary auditory cortex
- auditory association area
- primary olfactory cortex
