Brain Structures Flashcards
Dura
- Location: The outer meningeal layer of the brain and spinal cord
- Purpose: to protect the spinal cord
- Key Points: Tough mother. Durable. Epidural.
Corpus Callosum
- Location: larger fiber bundle connecting the right and left cerebral cortices
- Purpose: Connect and coordinate the two hemispheres of the brain - weight bearing.
- Key Points: Split brain
Cingulate Gyrus
- Location: Boundary of lobe. Superior to corpus callosum.
- Purpose: Limbic gyrus. Coordinates emotional responses to senses (i.e. smell, pain)
- Key points: Emotional memory smells. Emotions to pain.
Septum Pellucidum
- Location: Forms the medial wall of the lateral ventricles. Between the corpus callosum & fornix along the midline of the brain.
- Purpose: Connected to corpus callosum to separate the lateral ventricles.
- Key Points: Septo-optic dysplasia. “clear wall”
Fornix
- Location: Below corpus callosum, arch shaped
- Purpose: Connects hippocampus to mammillary body of hypothalamus
- Key Points: “Highway” from Hippocampus to Hypothalamus
Mammillary Bodies
- Location: Inferior to the hypothalamus on the underside of the brain
- Purpose: Acts as a relay from amygdala & hippocampus, project to thalamus. Processing of recognition memory associated with smell.
- Key Points: Smell to memories. Part of hypothalamus
Thalamus
-Location: Large, egg shaped collection of nuclei in the center of the cerebrum
-Purpose: Relay info to cerebral cortex, process emotional & memory, integrate sensations, regulate consciousness, arousal & attention.
-Key Points: “relay station”
“selective filter”
Hypothalamus
- Location: Inferior to the thalamus
- Purpose: Temperature, hunger, sleep-wake cycles, release hormones, emotional expression
- Key Points: Autonomic control center, master switchboard, thermostat
Brainstem
- Location: Bottom posterior extension of brain to spinal cord
- Purpose: To carry motor and sensory tracts to the spinal cord. Control equilibrium, cardiovascular, respiration, etc
- Key Points: Midbrain, Pons, Medulla
Medulla
- Location: Bottom of brainstem - continuous with spinal cord
- Purpose: Crossing of motor tracts, cardiac & respiratory centers. CN IX, X, XI, XII
- Key Points: Olives, Pyramids, tracts decussate
Putamen
-Location: Part of basal ganglia. Round structure located at the base of the forebrain.
-Purpose: Excitatory. Works with caudate & GP for regulation / timing of mvmt
-Key Points: Basal ganglia.
+GP = Lenticular nucleus
+Caudate = Corpus Striatum
Globus Pallidus
-Location: Part of basal ganglia
-Purpose: Excitatory. Works with caudate & putamen to regulate / time mvmt
-Key Points: Basal ganglia
+Putamen = Lenticular nucleus
Caudate
-Location: Part of basal ganglia
-Purpose: Involved with motor planning. Role in inhibitory control to time mvmt
-Key Points: Basal ganglia
+Putamen = Corpus striatum
Amygdala
-Location: Almond shaped collection of nuclei in temporal lobe
-Purpose: Mediates fear, anger, and anxiety. Interprets facial expressions and social signals.
-Key Points: Amygdala = Almond
Mig fighter plane = scary!
Hippocampus
- Location: Part of limbic system. Interior to hypothalamus & fornix. Medial temporal lobe.
- Purpose: Long term memory storage
- Key Points: “You would always remember if you saw a hippo on campus”
Pyramids
- Location: Part of the anterior surface of the medulla (medial to the olives)
- Purpose: Where axons projecting from the cortex to the spinal cord decussate in the medulla
- Key Points: Pyramids built layer by layer = tracts crossing making lateral lines of pyramids
Inferior colliculus
- Location: Dorsal, tectum of midbrain (superior aspects of brainstem), lower 2 of four small rounded bodies.
- Purpose: Important for orientation to auditory stimuli
- Key Points: Midbrain. Ears lower than eyes = inferior colliculi = auditory
Superior Colliculus
- Location: Dorsal, tectum of midbrain, upper 2 of four small rounded bodies
- Purpose: Important for orientation to visual stimuli
- Key Points: Midbrain. Eyes higher than ears = superior colliculi = visual
Substantia nigra
-Location: One of nuclei in basal ganglia circuit in midbrain. Substantia nigra pars compacta & Substantia nigra parts reticulata
-Purpose: SNpc gets info from putamen & caudate & sends info back; SNpc produced dopamine.
SNpr also gets input from putamen & caudate but sends input outside basal ganglia to control head & eye mvmt
-Key Points: SNpc degenerates w/ Parkinson’s disease. Dopamine. Movements.
Subthalamus
-Location: connected to basal ganglia. Separated from hypothalamus by
white matter fibers in internal capsule
-Purpose: Movement. Subthalamus has efferent fibers to caudate nucleus and putaman and input connections from caudate nucleus, putamen and substantia nigra.
-Key Points: Movement
Epithalamus
-Location: connected to limbic system
contains pineal gland
-Purpose: Sexual and hormonal functions
Sleep – wake cycle
Pineal Gland
- Location: inferior, posterior of thalamus; part of epithalamus
- Purpose: Causes Feeling of Sleepiness; Converts Nervous system signals to endocrine signals; Regulates Endocrine Functions; Secretes Hormone Melatonin
Pituitary Gland
Helps control following body processes:
- Growth
- Blood pressure
- Some aspects of pregnancy & childbirth
- Breast milk production
- Sex organ functions in both M/F
- Thyroid gland function
- Conversion of food into energy (metabolism)
- Water & osmolarity regulation in body
Commissural axons
between cortical hemispheres
Association axons
between regions of the same cortical hemisphere
Projection axons
between subcortical structures (thalamus, basal ganglia, brainstem, spinal cord) & cortex
Anterior commissure
backup to corpus callosum; connects two temporal lobes & amygdala; and may have role in sexuality
Posterior commissure
connects R & L diencephalon; role in pupillary light reflex
Tectum
dorsal part of mesencephalon and consists of superior and inferior colliculi. Superior is involved in visual processing and control of eye movements and inferior in auditory processing.
Internal Capsule - projection
- Connect cortex and diencephalon
- Bundle of nerves separating putamen, caudate nucleus, and thalamus
- So many fibers from so many areas run through here resulting in significant effects of a small lesion
External Capsule - projection
- Separates putamen and extreme capsule
- More fibers running with communication – major disruptive area
Extreme Capsule - projection
- Separates claustrum and insular cortex
- Claustrum =group of nuclei between external and extreme capsules
- Bidirectional communication with broca and wernicke area
Limbic System
- Structures: Hypothalamus, cingulate gyrus, hippocampus, amygdala, insula. —–Connections within are because of fornix and medial forebrain bundle.
- Primal system involved in survival
Limbic System -Memory
-Hippocampus: long term memory storage (short term memory: frontal lobes)
Limbic System - Olfaction
olfactory bulb and tract = cranial nerve 1
- Smells often trigger emotional memories - Old part of brain (smell very important for many animals)
Limbic System - Visceral
- maintain homeostasis of ANS
- coordinating visceral responses with cognitive, emotional & sensorimotor
behavior (avoid unpleasant stimuli, seek pleasant)
Limbic System - Emotion
- Feeding - seeking love & food gratification
- Fighting – seek social gratification
- Reproduction – seek sexual gratification
- Amygdala – mediates fear, anger, and anxiety
-Memory formation of emotionally arousing events
-Autism – smaller – deficiency of dendrites
– lack of emotional cues- Mamillary bodies - involved w/ emotion
Dorsolateral Prefrontal Cortex (PFC)
Voluntary emotional regulation
Ventromedial PFC
Automatic emotional regulation (i.e. crying, smiling)
Broca’s area
- Language output
- Broca’s area – output of verbal communication
- Corticobulbar tracts – link Broca’s to the muscles to produce speech
- Both Wernicke’s & Broca’s in left hemisphere
Wernicke’s area
- Comprehension
- Wernicke’s posterior part of temporal lobe – start making sense of what heard
- Both Wernicke’s & Broca’s in left hemisphere
Ventricular System
Lateral ventricles Foramen of Monro (connects) Third ventricle Cerebral aqueduct (of Sylvius) (connects) Fourth ventricle Central canal
CSF
-Purpose of CSF
cushioning of brain
exchange of nutrients and waste
transport of hormones
-Choroid plexus in all ventricles (most in lateral) produce CSF
-Arachnoid Villi reabsorb CSF and return to venus system
-Septum pellucidum – separates lateral ventricles
-3rd between thalami
-4th b/w pons & cerebellum
-Sinuses help
