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

Human Brain

4 Major Regions Cerebral Hemispheres Diencephalon Brain stem Cerebellum

1. Cerebral Hemispheres (Cerebrum) L & R hemispheres Corpus callosum: large fiber tract; connects 2 hemispheres Lobes: major regions (named for cranial bones) Parietal, frontal, 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

Parieto-occipital sulcus (on medial surface of hemisphere) Precentral gyrus Central sulcus Postcentral gyrus Frontal lobe Parietal lobe Parieto-occipital sulcus (on medial surface of hemisphere) Lateral sulcus Occipital lobe Temporal lobe Transverse cerebral fissure Cerebellum Pons Medulla oblongata Fissure Spinal cord (a deep sulcus) Gyrus Cortex (gray matter) Sulcus White matter (a) Figure 12.6a

Thin (2–4 mm) superficial layer of gray matter 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

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

Motor Areas Primary (somatic) motor cortex Premotor cortex Broca’s area Frontal eye field

Sensory areas and related association areas Primary motor cortex Motor areas Central sulcus Sensory areas and related association areas Primary motor cortex Primary somatosensory cortex Premotor cortex Somatic sensation Frontal eye field Somatosensory association cortex Broca’s area (outlined by dashes) Gustatory cortex (in insula) Taste Prefrontal cortex Working memory for spatial tasks Wernicke’s area (outlined by dashes) Executive area for task management Working memory for object-recall tasks Primary visual cortex Visual association area Vision Solving complex, multitask problems Auditory association area Hearing Primary auditory cortex (a) Lateral view, left cerebral hemisphere Primary motor cortex Motor association cortex Primary sensory cortex Sensory association cortex Multimodal association cortex Figure 12.8a

Posterior Motor Motor map in precentral gyrus Anterior Toes Jaw Tongue Primary motor cortex (precentral gyrus) Swallowing Figure 12.9

Sensory Areas Primary somatosensory cortex Somatosensory association cortex Visual areas Auditory areas Olfactory cortex Gustatory cortex Visceral sensory area Vestibular cortex

Sensory areas and related association areas Primary motor cortex Motor areas Central sulcus Sensory areas and related association areas Primary motor cortex Primary somatosensory cortex Premotor cortex Somatic sensation Frontal eye field Somatosensory association cortex Broca’s area (outlined by dashes) Gustatory cortex (in insula) Taste Prefrontal cortex Working memory for spatial tasks Wernicke’s area (outlined by dashes) Executive area for task management Working memory for object-recall tasks Primary visual cortex Visual association area Vision Solving complex, multitask problems Auditory association area Hearing Primary auditory cortex (a) Lateral view, left cerebral hemisphere Primary motor cortex Motor association cortex Primary sensory cortex Sensory association cortex Multimodal association cortex Figure 12.8a

Posterior Sensory Anterior Sensory map in postcentral gyrus Genitals Primary somato- sensory cortex (postcentral gyrus) Intra- abdominal Figure 12.9

Primary visual (striate) cortex Visual Areas Primary visual (striate) cortex Extreme posterior tip of the occipital lobe Receives visual information from the retinas

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

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

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

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)

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)

2. Diencephalon (interbrain) 3 main structures: Thalamus: relay station for incoming info Hypothalamus: 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

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

Brain Stem

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

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 (HiB)

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