test 2 Flashcards
diencephalon
contains the thalamus, hypothalamus, and epithalamus
Within the thalamus:
, information is sorted and “edited.” Impulses having to do with similar functions are relayed as a group to the appropriate area of the sensory cortex. The thalamus also mediates motor activities between the primary motor cortex, basal nuclei, and cerebellum. It is also involved with cortical arousal, learning, and memory.
The hypothalamus
is the main visceral control center of the body and is the major integrator for homeostasis.
pineal glad (epithalamus)
makes melatonin
brainstem consists of
midbrain, pons, medulla oblongata
midbrain
is a pathway for fiber tracts running between lower and higher brain center. connects amygdala and ANS pathways to control “fight or flight” response. it contains superior and inferior colliculi.
pons
is a pathway for fiber tracts running between lower and higher brain centers. it forms a bridge for fibers from the motor cortex to run the cerebellum. it aids the medulla oblongata in smoothing out transitions between breaths
Medulla oblongata
a pathway for fiber tracts running between lower and higher brain centers. it contains pyramids where motor fibers crossover, and as a result each cerebral hemisphere controls voluntary movements on contralateral side of the body. it also contains: cardiovascular control center, vasomotor center, respiratory center.
cerebellar activity:
is subconscious and ipsilateral
reticular activating system
extends through the central core of the medulla oblongata, pons, and midbrain. It filters the flood of sensory inputs by sorting out repetitive, familiar, or weak signals, but unusual, significant, or strong impulses do reach consciousness.
The limbic association area/system
is a ring of structures that surround the brain stem and includes portions of the cerebral cortex, basal nuclei, and diencephalon (thalamus and hypothalamus). It plays a key role in emotional displays such as laughing, crying, blushing, expressions of fear, and memory processing. It also works with higher brain centers in controlling basic behavioral patterns, including survival actions and sociosexual behaviors conducive to mating. The limbic system (emotional brain) interacts with the prefrontal cortex (cognitive brain) to form relationships between our thoughts and feelings.
hippocampus
produces episodic memory of past personal history like times, places, emotions, who, what, when, where, why knowledge (short-term memory) and aids in converting them into long-term memory. If damaged, a person cannot build new memories so current experiences fade, but older memories made before the damage are intact. Movies that portray this kind of damage are Memento and 50 First Dates.
amygdala
is responsible for processing and experiencing emotions. It acts as a processing center that receives incoming messages from our sense and internal organs to create an appropriate response to the messages it receives. It is critical for responding to perceived threats (angry or fearful expressions) with fear and aggression.
temporal lobe
Initial cortical processing for hearing
Wernicke’s area
Responsible for comprehension and formulation of coherent patterns of speech
somatosensory cortex
Initial cortical processing for sensations arising from the surface of the body
limbic association cortex
Primarily concerned with motivation and emotion
corpus callosum
A thick band of axons passing between the two hemispheres
primary motor cortex
Triggers voluntary movement by activating motor neurons
occipital lobe
Initial cortical processing for vision
Broca’s area
Responsible for speaking ability
premotor area
Programs complex sequences of movement
prefrontal association cortex
Lesions in this area result in changes in personality and social behavior
dorsal horn
Contains cell bodies of interneurons upon which afferent neurons terminate
dorsal root
Afferent fibers enter the spinal cord through this structure
dorsal root ganglion
Contains cell bodies of afferent neurons
ventral horn
Contains cell bodies of the efferent motor neurons supplying skeletal muscles
ventral root
Efferent fibers leave the spinal cord through this structure
cerebellum
Helps monitor and coordinate slow, sustained contractions, especially those related to support and posture. Disorder of this structure is characterized by an intention tremor. Compares the “intentions” of the higher centers with the “performance” of the muscles, and corrects any “errors”
hypothalamus
Controls anterior pituitary hormone secretion. Controls thirst, urine output, food intake, and body temperature. Contains the autonomic nervous system coordinating center. Plays a role in emotion and behavioral patterns
brainstem
Contains centers for respiration, heart and blood vessel function, and many digestive activities
basal nuclei
Inhibits muscle tone throughout the body. Damage to this structure is associated with a resting tremor
cerebral cortex
Initiates all voluntary movement; accomplishes final sensory perception
a first-order neuron
The initial neuron in an ascending (sensory) pathway
second-order neurons
The interneurons in the dorsal horn of the spinal cord or medullary nuclei are second-order neurons, which transmit sensory impulses to either the thalamus or cerebellum.
Dorsal white column
Ascending tract that carries impulses about well-localized fine touch, vibration, two-point discrimination, conscious proprioception to thalamus. Cross at medulla oblongata.
cerebral cortex
is the “executive suite” where the conscious mind is found. It enables us to be aware of ourselves, our sensations, to communicate, remember, understand, and initiate voluntary movements.
Generalizations of the cerebral cortex include:
- Three functional areas: motor, sensory, and multimodal association areas.
- Each hemisphere is chiefly concerned with the sensory and motor functions of the contralateral side of the body.
- Lateralization, or specialization, of cortical functions - each hemisphere is not exactly equal in functions.
- Higher order functions integrate multiple domains and conscious behavior involves the entire cortex.
cerebral cortex
is divided into five lobes - frontal, parietal, temporal, occipital, and insula.
central sulcus
separates the frontal and parietal lobes.
corpus callosum
The cerebral hemispheres are connected by a tract (bundle of axons)
motor cortex
the region of the cerebral cortex involved with the planning, control, and execution of voluntary movements.
primary motor cortex
is located in the precentral gyrus of the frontal lobe. Upper motor neurons generate neural impulses that pass down the spinal cord to control the execution of movement.
premotor cortex and supplemental motor cortex
premotor areas) are located anterior to the precentral gyrus in the frontal lobe. The supplemental motor cortex is responsible for planning movements by selecting and sequencing basic motor movements into complex tasks. The premotor cortex aids in the sensory guidance of movement and the spatial guidance of reaching.
Broca’s area
is located in the left anterior, inferior region of the premotor area in the frontal lobe. It is a special motor speech area that directs muscle movement plans involved with language production (speech, sign language, writing, typing).
Upper motor neurons (UMN)
originate in the primary motor cortex and are the main source of voluntary movement. They carry motor information down spinal cord tracts (specifically lateral and anterior corticospinal tracts) to synapse with lower motor neurons. UMN lesions can arise as a result of stroke, multiple sclerosis, spinal cord injury or other brain injury. Symptoms can include spastic paralysis, decreased motor control, and increased deep tendon reflexes and Babinski’s sign.
Lower motor neurons (LMN)
are also called somatic motor neurons. LMNs originate in the anterior horns of the brain stem or spinal cord. All voluntary movement relies on LMNs, which innervate skeletal muscles fibers to act as a link between UMNs and skeletal muscles. Damage to LMNs can be due to nerve injury, polio, ALS. Symptoms can include flaccid paralysis, absent deep tendon reflexes, and muscle atrophy.
gray matter
is neural cell bodies, axon terminals, and dendrites as well as all nerve synapses
white matter
matter is bundles of axons covered in myelin.
Tracts
are bundles of axons in the CNS, whereas nerves are bundles of axons in the peripheral nervous system.
