Nervous System Chapter

Spinal Cord Bundle of nerves Within vertebral canal Bathed in cerebral spinal fluid Branches to ennervate body

Meninges Covering protective layers Contains nourishing, O rich fluids Isolates brain Blood brain barrier Blood vessel walls impermeable to large molecules Dura mater Hard outermost covering Arachnoid Spider Inner surface of dura Space filled with fluid Pia mater Innermost meninge On surface of brain

Meninges

Dura Mater

Sagittal Sinus

Falx Cerebri

Falx Cerebri

Tentorium Cerebelli

Arachnoid mater

Ventricles Spaces Choroid plexus Produce cerebrospinal fluid Cells & capillaries secrete fluid into ventricle Produce cerebrospinal fluid Support Nutrients, Hormones, Oxygen Waste products

Ventricles

Brain 1.4 Kg (~3 lbs) 98% of neural tissue 15-33 Billion neurons 10,000 synapses each 1 mm3 = 1 billion synapses Contains processing centers

Brain Regions Cerebrum Diencephalon Midbrain Pons Medulla oblongata Cerebellum

Cerebrum Aka Telencephalon Cerebrum divided into 2 hemispheres Cerebral hemispheres r/l Outer surface of folds Gyrus- ridge Sulcus- depression Deep folds Fissures Longitudinal fissure Central sulcus Lobes Frontal Temporal Parietal Occipital

Cerebral Hemispheres

Central Sulcus

Grey Matter Cell bodies of nerve cells White matter Axons

Cerebrum Function Conscious thoughts Sensations Intellectual functions Memory storage & retrieval Complex movements Interpretation Wernicke’s area Emotions Limbic system

Cerebrum Landmarks Located Anterior/posterior to central sulcus Precentral gyrus Primary motor cortex Voluntary movement Postcentral gyrus Primary sensory cortex Receives information

Somatosensory

Cerebrum Landmarks Broca’s area Wernicke’s area Speech Physical coordination of speech organs Wernicke’s area Auditory association Interpretation, language skills

Lateralization Pattern & face recognition Spatial relationships, non verbal thinking, emotion processing Language, math, logical operations, serial processing Detail, speed optimized activities for muscle control & processing fine visual & auditory details

Corpus Callosum Connects 2 hemispheres Hemispheric lateralization Largest white matter structure 200-250 million contralateral axonal projections Conveys information between regions of brain 2 hemispheres Diencephalon Brain stem Cerebellum Spinal cord

Corpus Callosotomy Symptoms of refractory epilepsy reduced by severing corpus callosum Modern procedures sever anterior portion only Regions between frontal and temporal lobes

Diencephalon Hollow Connected to cerebrum Contains Pineal gland- internal clock Thalmus Relay & processing centers for sensory information Receives auditory, somatosensory & visual sensory signals Conscious & unconscious Hypothalmus Emotions- limbic Rage, fear, sexual arousal, hunger, thirst Autonomic function- homeostatsis, sleep/wake cycle Hormone production Hypophysis- Pituitary gland

Thalmus

Hypothalmus

Limbic System

Hypophysis

Brain Stem Mesencephalon Midbrain Pons Medulla oblongata Contain processing centers Relay stations for information traveling between cerebrum & cerebellum

Midbrain Mesencephalon Process visual & auditory information Generate involuntary motor responses Consciousness maintenance Colliculi Visual & auditory Superior Eye, head, neck reflexes to visual stimuli Inferior Head, neck, trunk reflexes to auditory stimuli

Colliculi

Midbrain- Amygdala Medial temporal lobe Emotional content of new memories Aggression Jealousy Fear Involved in addiction behaviors Overrides logic May habituate to pleasure pathways Absence of cues triggers override response

Pons “bridge” Connects cerebellum to brain stem Relay center for sensory information between cerebellum and cerebrum Initiates REM sleep Somatic & visceral control Breathing control center

Pons

Pons

Medulla Oblongata Attaches to spinal cord Relays info to thalmus & other brain stem centers Autonomic control Heart rate Blood pressure Respiration- breathing control center Basic rhythm of breathing Stimulates diaphragm & rib muscles Digestion

Medulla Oblongata

Medulla Oblongata

Cerebellum White & grey matter Voluntary & involuntary motor activities Autonomic processing center Posture for balance Fine tune movements Coordination of skeletal muscles Muscle tone Responses based on Sensory input Stored memories Previous moments

Cerebellum- Vermis & Folia