WarmUp 1 List and describe the 5 elements

Warm-Up 1. List and describe the 5 elements of a reflex arc. 2. List an example of a reflex. 3. What is the difference between a reflex and a voluntary reaction?

Human Brain

4 Major Regions Cerebral Hemispheres 2. Diencephalon 3. Brain stem 4. Cerebellum 1.

1. Cerebral Hemispheres (Cerebrum) L & R hemispheres Corpus callosum: large fiber tract; connects 2 hemispheres Lobes: major regions (named for cranial bones) Parietal, Parietal frontal, frontal occipital, occipital temporal Gyri (gyrus) = elevated ridges of tissue Sulci (sulcus) = shallow grooves Fissures = deeper grooves, separate large regions of brain Motor & sensory function: opposite hemispheres

Cerebral Cortex Grey matter “Executive suite” conscious mind

Functions of the Major Lobes

Cerebral Hemispheres • Surface markings • Central sulcus • Separates the precentral gyrus of the frontal lobe and the postcentral gyrus of the parietal lobe • Longitudinal fissure • Separates the two hemispheres • Transverse cerebral fissure • Separates the cerebrum and the cerebellum Copyright © 2010 Pearson Education, Inc.

Precentral gyrus Frontal lobe Central sulcus Postcentral gyrus Parietal lobe Parieto-occipital sulcus (on medial surface of hemisphere) Lateral sulcus Occipital lobe Temporal lobe Transverse cerebral fissure Cerebellum Pons Medulla oblongata Spinal cord Fissure (a deep sulcus) Gyrus Cortex (gray matter) Sulcus White matter (a) Copyright © 2010 Pearson Education, Inc. Figure 12. 6 a

Cerebral Cortex • Thin (2– 4 mm) superficial layer of gray matter • 40% of the mass of the brain • Site of conscious mind: awareness, sensory perception, voluntary motor initiation, communication, memory storage, understanding Copyright © 2010 Pearson Education, Inc.

Functional Areas of the Cerebral Cortex • The three types of functional areas are: • Motor areas—control voluntary movement • Sensory areas—conscious awareness of sensation • Association areas—integrate diverse information • Conscious behavior involves the entire cortex Copyright © 2010 Pearson Education, Inc.

Motor Areas • Primary (somatic) motor cortex • Premotor cortex • Broca’s area •

Motor areas Central sulcus Primary motor cortex Premotor cortex Frontal eye field Broca’s area (outlined by dashes) Prefrontal cortex Working memory for spatial tasks Executive area for task management Working memory for object-recall tasks Solving complex, multitask problems (a) Lateral view, left cerebral hemisphere Sensory areas and related association areas Primary somatosensory cortex Somatic Somatosensory sensation association cortex Gustatory cortex (in insula) Taste Wernicke’s area (outlined by dashes) Primary visual cortex Visual association area Auditory association area Primary auditory cortex Vision Hearing Motor association cortex Primary sensory cortex Primary motor cortex Sensory association cortex Multimodal association cortex Copyright © 2010 Pearson Education, Inc. Figure 12. 8 a

Posterior Motor map in precentral gyrus Anterior Toes Jaw Tongue Swallowing Copyright © 2010

Sensory Areas • Primary somatosensory cortex • Somatosensory association cortex • Visual areas • Auditory areas Copyright © 2010 Pearson Education, Inc. • Olfactory cortex • Gustatory cortex • Visceral sensory area • Vestibular cortex

Motor areas Central sulcus Primary motor cortex Premotor cortex Frontal eye field Broca’s area (outlined by dashes) Prefrontal cortex Working memory for spatial tasks Executive area for task management Working memory for object-recall tasks Solving complex, multitask problems (a) Lateral view, left cerebral hemisphere Sensory areas and related association areas Primary somatosensory cortex Somatic Somatosensory sensation association cortex Gustatory cortex (in insula) Taste Wernicke’s area (outlined by dashes) Primary visual cortex Visual association area Auditory association area Primary auditory cortex Vision Hearing Motor association cortex Primary sensory cortex Primary motor cortex Sensory association cortex Multimodal association cortex Copyright © 2010 Pearson Education, Inc. Figure 12. 8 a

Posterior Sensory Anterior Sensory map in postcentral gyrus Genitals Primary somatosensory cortex (postcentral gyrus)

Visual Areas • Primary visual (striate) cortex • Extreme posterior tip of the occipital

Multimodal Association Areas • Receive inputs from multiple sensory areas • Send outputs to multiple areas • Allow us to give meaning to information received, store it as memory, compare it to previous experience, and decide on action to take Copyright © 2010 Pearson Education, Inc.

Multimodal Association Areas • Three parts • Anterior association area (prefrontal cortex) • Posterior

Anterior Association Area (Prefrontal Cortex) • Most complicated cortical region • Involved with intellect, cognition, recall, and personality • Contains working memory needed for judgment, reasoning, persistence, and conscience • Development depends on feedback from social environment Copyright © 2010 Pearson Education, Inc.

Posterior Association Area • Large region in temporal, parietal, and occipital lobes • Plays a role in recognizing patterns and faces and localizing us in space • Involved in understanding written and spoken language (Wernicke’s area) Copyright © 2010 Pearson Education, Inc.

2. Diencephalon (interbrain) 3 main structures: 1. Thalamus: relay station for incoming info 2. Hypothalamus: A. B. C. D. E. F. 3. Autonomic control center (heart rate, BP, digestion) Emotional response (limbic system) Body temperature regulation Regulate food intake Sleep-wake cycles Control endocrine system pituitary gland at base Epithalamus: pineal gland (sleep-wake cycle)

Diencephalon

Dorsal nuclei Medial Lateral dorsal posterior Pulvinar Anterior nuclear group Reticular nucleus Ventral posteroanterior lateral Medial geniculate body Lateral geniculate body Ventral nuclei (a) The main thalamic nuclei. (The reticular nuclei that “cap” the thalamus laterally are depicted as curving translucent structures. ) Copyright © 2010 Pearson Education, Inc. Figure 12. 13 a

Thalamic Function • Gateway to the cerebral cortex • Sorts, edits, and relays information • Afferent impulses from all senses and all parts of the body • Impulses from the hypothalamus for regulation of emotion and visceral function • Impulses from the cerebellum and basal nuclei to help direct the motor cortices • Mediates sensation, motor activities, cortical arousal, learning, and memory Copyright © 2010 Pearson Education, Inc.

Hypothalamus • Contains many nuclei • Example: mammillary bodies • Paired anterior nuclei • Olfactory relay stations • Infundibulum—stalk that connects to the pituitary gland Copyright © 2010 Pearson Education, Inc.

Paraventricular nucleus Anterior commissure Preoptic nucleus Anterior hypothalamic nucleus Supraoptic nucleus Suprachiasmatic nucleus Fornix Arcuate nucleus Pituitary gland Optic chiasma Infundibulum (stalk of the pituitary gland) (b) The main hypothalamic nuclei. Copyright © 2010 Pearson Education, Inc. Dorsomedial nucleus Posterior hypothalamic nucleus Lateral hypothalamic area Ventromedial nucleus Mammillary body Figure 12. 13 b

Hypothalamic Function • Autonomic control center for many visceral functions (e. g. , blood pressure, rate and force of heartbeat, digestive tract motility) • Center for emotional response: Involved in perception of pleasure, fear, and rage and in biological rhythms and drives Copyright © 2010 Pearson Education, Inc.

Hypothalamic Function • Regulates body temperature, food intake, water balance, and thirst • Regulates sleep and the sleep cycle • Controls release of hormones by the anterior pituitary • Produces posterior pituitary hormones Copyright © 2010 Pearson Education, Inc.

Epithalamus • Pineal gland—extends from the posterior border and secretes melatonin • Melatonin—helps regulate

3. Brain Stem Programmed, automatic behaviors for survival 3 regions: 1. Midbrain: vision, hearing, reflex 2. Pons: breathing 3. Medulla oblongata: heart rate, BP, breathing, swallowing, vomiting, coughing, sneezing

Brain Stem

Brain Stem • Controls automatic behaviors necessary for survival • Associated with 10

Frontal lobe Olfactory bulb (synapse point of cranial nerve I) Optic chiasma Optic nerve (II) Optic tract Mammillary body Midbrain Pons Temporal lobe Medulla oblongata Cerebellum Spinal cord Copyright © 2010 Pearson Education, Inc. Figure 12. 14

Optic chiasma Optic nerve (II) Crus cerebri of cerebral peduncles (midbrain) Diencephalon • Thalamus • Hypothalamus Mammillary body View (a) Thalamus Hypothalamus Diencephalon Midbrain Oculomotor nerve (III) Trochlear nerve (IV) Pons Brainstem Medulla oblongata Trigeminal nerve (V) Pons Middle cerebellar peduncle Abducens nerve (VI) Facial nerve (VII) Vestibulocochlear nerve (VIII) Pyramid Glossopharyngeal nerve (IX) Hypoglossal nerve (XII) Vagus nerve (X) Ventral root of first cervical nerve Decussation of pyramids Accessory nerve (XI) Spinal cord (a) Ventral view Copyright © 2010 Pearson Education, Inc. Figure 12. 15 a

Crus cerebri of cerebral peduncles (midbrain) Thalamus View (b) Infundibulum Pituitary gland Superior colliculus Inferior colliculus Trochlear nerve (IV) Trigeminal nerve (V) Pons Superior cerebellar peduncle Middle cerebellar peduncle Facial nerve (VII) Abducens nerve (VI) Glossopharyngeal nerve (IX) Hypoglossal nerve (XII) Inferior cerebellar peduncle Vestibulocochlear nerve (VIII) Olive Thalamus Vagus nerve (X) Hypothalamus Diencephalon Midbrain Accessory nerve (XI) Pons Brainstem Medulla oblongata (b) Left lateral view Copyright © 2010 Pearson Education, Inc. Figure 12. 15 b

Pons • Connect higher brain centers and the spinal cord • Relay impulses between the motor cortex and the cerebellum • Origin of cranial nerves V (trigeminal), VI (abducens), and VII (facial) • Nuclei that help maintain normal rhythm of breathing Copyright © 2010 Pearson Education, Inc.

Medulla Oblongata • Joins spinal cord at foramen magnum • Relay sensory information from muscles and joints to cerebellum • Cranial nerves VIII, X, and XII are associated with the medulla • Mediates responses that maintain equilibrium Copyright © 2010 Pearson Education, Inc.

Medulla Oblongata • Autonomic reflex centers • Cardiovascular center • Cardiac center adjusts force and rate of heart contraction • Vasomotor center adjusts blood vessel diameter for blood pressure regulation • Respiratory centers • Generate respiratory rhythm • Control rate and depth of breathing Copyright © 2010 Pearson Education, Inc.

Medulla Oblongata • Additional centers regulate • Vomiting • Hiccuping • Swallowing • Coughing

Reticular formation Fourth ventricle Choroid Hypoglossal nucleus (XII) plexus Dorsal motor nucleus of vagus (X) Inferior cerebellar peduncle Lateral nuclear group Medial nuclear group Raphe nucleus Medial lemniscus (c) Medulla oblongata Copyright © 2010 Pearson Education, Inc. Solitary nucleus Vestibular nuclear complex (VIII) Cochlear nuclei (VIII) Nucleus ambiguus Inferior olivary nucleus Pyramid Figure 12. 16 c

4. Cerebellum Balance, equilibrium, timing of skeletal muscle activity

The Cerebellum • 11% of brain mass • Dorsal to the pons and medulla

Cognitive Function of the Cerebellum • sequences of events during complex movements • nonmotor

12 Cranial Nerve Mnemonic: On old Olympus' towering top a Fin and German viewed some hops • O: olfactory nerve (CN I) • O: optic nerve (CN II) • O: oculomotor nerve (CN III) • T: trochlear nerve (CN IV) • T: trigeminal nerve(CN V) • A: abducens nerve (CN VI) • F: facial nerve (CN VII) • A: auditory (or vestibulocochlear) nerve (CN VIII) • G: glossopharyngeal nerve (CN IX) • V: vagus nerve (CN X) • S: spinal accessory nerve (CN XI) • H: hypoglossal (CN XII) Copyright © 2010 Pearson Education, Inc.

Protection of CNS Meninges: connective tissue covering CNS structures Dura mater (leathery outer), arachnoid mater (web -like middle), pia mater (surface of brain) Meningitis: inflammation of meninges; bacterial or viral infection Cerebrospinal fluid (CSF): watery cushion to protect NS from trauma Lumbar (spinal) tap – test for infection, tumors, multiple sclerosis

Meningitis

Symptoms of Meningitis

Treatment for Meningitis Bacterial antibiotics Herpes meningitis antiviral meds IV fluids Prevention: vaccines for bacterial infections (Hi. B)

Blood-Brain Barrier: endothelial cells in capillaries prevent substances from crossing into brain NO: YES: Urea Toxins Proteins White blood cells Bacteria Most drugs Water Glucose Amino acids Gases Fat-soluble substances Some drugs: anesthetics, alcohol, nicotine