Central forebrain core surrounded by cerebrum. Composed of three paired (L/R) gray matter structures. 1. Thalamus: location- deep, hidden brain region, 80% diencephalon. Structure- paired, egg shaped masses of gray matter nuclei groups, communicates directly with cerebral cortex. Functions- receives all afferent (sensory) impulses, relays info to cerebral cortex, sorts out/edits info associated with a similar function, sends it to cerebral cortex as a group, and mediates sensation, motor activities, cortical arousal, learning, and memory.
2.Hypothalamus: location- directly inferior to thalamus. Structure- composed of several small nuclei of varying function, includes mammillary bodies, infundiulum (pituitary stalk). Functions- main body visceral (autonomic control center) regulates blood pressure, heartbeat rate/force, digestive tract motility, breathing rate/depth, other visceral activities. Other function emotional response center, body temp regulation, food intake, water balance/ thirst, sleep/wake cycles.
3. Epithalamus: Location- dorsal part of diencephalon, situated above/behind thalamus. Structure- contains pineal gland. Function- pineal gland produces melatonin, hormone involved in sleep regulation, sleep wake cycles (circadian rhythms), mood. Pineal gland interacts with hypothalamus.
Just superior to brain stem; not part of.
Widespread neural networks functioning together but not localized to any single brain region.
1. limbic system- situated around thalamus, composed of hippocampus, amygdala, fornix, and cingulate gyrus. Controls emotional response, memory info.
2. Reticular formation- located in brain stem, made up of raphe nuclei, medial nuclei, lateral nuclei group. Regulates cerebral cortex cortical arousal (RAS), filters sensory input, control of motor behavior.
Selective 3 layer barrier composed of: 1. capillary endothelium with tight junctions. 2. thick basal lamina- basement membrane, connective tissue. 3. astrocyte feet= glial = starlike. Located in most brain areas, not in brain stem vomiting center & hypothalamus (areas analyzing blood make up). Selective substance passage: **1. Restricts- microbes (bacteria) red- blood cells proteins, some toxins. 2. Allows- O2/CO2, glucose, amino acids, fatty acids, lipids, white blood cells, anesthetics, alcohol.