1. 17.2 THE CENTRAL NERVOUS SYSTEM

2. The Central Nervous System (CNS) 2 parts to CNS: 1. The spinal cord 2. The brain Communicates with Peripheral Nervous System (See next slide for details)

3. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central Nervous System Peripheral Nervous System autonomic nervous system (to smooth muscle, cardiac muscle, and glands) parasympathetic division sympathetic division spinal cordbrain spinal nerves cranial nerves motor fibers sensory fibers somatic nervous system (to skeletal muscles)

4. The Spinal Cord The spinal cord extends from the base of the brain through a large opening in the skull and into the vertebral canal. Meninges: protective membrane that surrounds spinal cord and brain Cerberospinal fluid: found between meninges and brain or spinal cord Provides cushioning

5. Structure of the Spinal Cord The spinal nerves project from the cord between the vertebrae. Fluid-filled intervertebral disks cushion and separate the vertebrae. A cross section of the spinal cord shows a central canal, gray matter, and white matter.

6. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. spinal cord spinal nerve vertebra intervertebral disk

7. Fig. 17.8b Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. dorsal white matter gray matter central canal meninges b.ventral spinal nerve ventral root dorsal root ganglion

8. Functions of the Spinal Cord The spinal cord provides a means of communication between the brain and the peripheral nerves that leave the cord. The spinal cord is also the center for thousands of reflex arcs. sensory neuron  integrative neuron in spinal cord  motor neuron Action potential initiated without brain’s involvement

9. The Brain The four major parts of the brain (in order of highest to lowest functioning) the cerebrum higher though processes the diencephalon integrative functions the cerebellum receives sensory and motor input the brain stem Oldest part of brain (in terms of evolution) Reflex arcs: heartbeat, breathing, blood pressure

10. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. skull meninges Diencephalon pons spinal cord Cerebellum fourth ventricle pineal gland hypothalamus thalamus (surrounds the third ventricle) third ventricle lateral ventricle Cerebrum corpus callosum pituitary gland Brain stem midbrain medulla oblongata a. Parts of brain

11. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Occipital lobe hand face tongue central sulcus Parietal lobe primary somatosensory area somatosensory association area primary taste area general interpretation area primary visual area visual association area sensory speech (Wernicke’s) area primary auditory area auditory association area Temporal lobe lateral sulcus prefrontal area motor speech (Broca’s) area premotor area primary motor area Frontal lobe leg trunk arm

13. The Cerebrum (aka Cerebral Cortex) The cerebrum is the largest portion of the brain. It is the last center to receive sensory input and carry out integration before commanding voluntary motor responses. The cerebrum carries out the higher thought processes required for learning and memory and for language and speech.

14. The Cerebrum The Cerebral Hemispheres The cerebrum is divided into the left and right cerebral hemispheres. Shallow grooves divide each hemisphere into lobes. The cerebral cortex a thin but highly convoluted outer layer of gray matter that covers the cerebral hemispheres.

15. The Cerebrum Primary Motor and Sensory Areas of the Cortex The primary motor area is located in the frontal lobe. The primary somatosensory area is located in the parietal lobe. Association Areas Association areas are places where integration occurs. Cerebral Palsy May be caused by O 2 deprivation during birth which damages motor and association areas (may cause paralysis, spasms, lack of motor control)

16. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Toes Ankle Knee Hip Trunk Shoulder A r m Ring finger Index finger Thumb Neck Eyelid and eyeball Lips and jaw Face Tongue Genitals Hip Trunk Neck Shoulder Little finger Ring finger Middle finger Index finger Face Lips, teeth, gums, and jaw Tongue Pharynx a. Prima ry motor areab. Primary somatosensory area Intra-abdominal Nose Eye Thump Leg Foot Toes Elbow Arm Forearm wrist Hand Pharynx Middle finger Little finger Hand Wrist Foreman Elbow

17. The Cerebrum Processing Centers Processing centers of the cortex receive information from the other association areas and perform higher-level analytical functions. Wernicke’s Area: understand written and spoken language Broca’s Area: speech muscle control Central White Matter Most of the rest of the cerebrum beneath the cerebral cortex is composed of white matter. Basal Nuclei Masses of gray matter located deep within the white matter are called basal nuclei.

18. Fig. 17.14a Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. motor speech (Broca’s area) primary motor area sensory speech (Wernicke’s area) primary visual area primary auditory area

19. The Diencephalon The hypothalamus and the thalamus are in the diencephalon. The hypothalamus is the integrating center that helps maintain homeostasis by regulating hunger, sleep, thirst, body temperature, and water balance. The thalamus integrates sensory input from the visual, auditory, taste, and somatosensory systems. The pineal gland is located in the diencephalon. It secretes the hormone melatonin which is responsible for normal body rhythms.

20. Fig. 17.12 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. hippocampus thalamus hypothalamus olfactory bulb olfactory tract corpus callosum amygdala

21. The Cerebellum The cerebellum receives sensory input from the joints, muscles, and other sensory pathways about the present position of body parts. It also receives motor output from the cerebral cortex about where these parts should be located. The cerebellum maintains balance and posture.

22. The Brainstem The brain stem contains: Midbrain: relay station Pons: bundles of axons traveling b/t cerebellum and rest of brain medulla oblongata: contains a number of reflex centers for regulating heartbeat, breathing, and blood pressure.

23. Electroencephalograms The electrical activity of the brain can be recorded in the form of an electroencephalogram (EEG). http://www.youtube.com/watch?v=h5f56Ynb01E