Brain structures PDF

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Hindbrain, Midbrain, & Forebrain...

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Brain Structure

Hindbrain (1) brain stem - includes medulla oblongata & pons (a) medulla oblongata - breathing, heart rate (HR), blood pressure (BP), digestion (b) pons (above medulla) - connects 2 halves of cerebellum, regulates states of arousal (pon’s raphe nucleus - contains serotonin which triggers and maintains slow wave sleep) (2) cerebellum - balance, smooth coordinated movements

Midbrain - all information between the brain and spinal cord passes through the midbrain (1) substantia nigra - part of the extra pyramidal motor system (EMS) - movement (smoothness, initiation, termination, directedness) is modulated by EMS *Parkinson’s disease - degeneration of substantia nigra result in low levels of dopamine in the basal ganglia - disease is characterized by tremors and disorders of voluntary movement (2) reticular formation - connects spinal cord, hindbrain, midbrain to thalamas & forebrain - involved in sleep, arousal, reflexes - reticular activating system (RAS) - extends to the thalamas - crucial for maintaining waking state, arousal, and attention - filters out irrelevant information

Forebrain - consists of central core (diencephalons) & right and left hemispheres (cerebrum) (1) hypothalamas -exerts control over autonomic nervous system (ANS) and endocrine system (viz. pituitary glands) - maintains body’s homeostasis - temperature, fluids, metabolism, appetite for specific nutrients (hypothalamas monitors body’s internal states) - also involved in motivated behavior (drinking, feeding, sex, aggression, & maternal behavior) & reward (pleasure) associated with these behaviors & its regulation - also pain mediation (2) thalamas - central “switching station” - relays incoming sensory information to the cortex except olfactory (sense of smell) (3) basal ganglia - includes caudate nucleus, globus pallidus & putamen - codes and relays information associated with control of voluntary movement (4) limbic system - mediates emotional components of behavior (a) amygdala - integrates and directs emotional behavior - attaches emotional significance to information it receives - mediates defense/aggressive behavior (b) septum - inhibits emotionality; also a pleasure center (c ) hippocampus - memory processing (transfers short term to long term memory) (d) cortex - higher cognitive, sensory, and motor functioning (judgment, comprehension, language, personality, concentration, abstract thinking, interpretation of sensory information) - 4 lobes (frontal, temporal, parietal, occipital)...