Chapter 13 Nervous System (Part 2) Lecture Outline PDF

Chapter 13 Nervous System (Part 2) 1 The Brain Subconscious – controls, channels Conscious – largest part..... o The Cerebrum// The cerebrum (or telencephalon) is the largest portion of the human brain. Communicates with, and coordinates activities of, other...

Chapter 13 Nervous System (Part 2) 1 The Brain Subconscious – controls, channels Conscious – largest part..... o The Cerebrum// The cerebrum (or telencephalon) is the largest portion of the human brain. Communicates with, and coordinates activities of, other parts of the brain. Divided into left and right cerebral hemispheres. Divided by longitudinal fissure. 2 The Human Brain 3 0071 4 The Brain Gray matter (outer part) of cerebrum consists of cerebral cortex and basal nuclei. Cerebral cortex is a highly convoluted outer layer that covers the cerebral hemispheres – sensation, voluntary movement, thought processes. Basal nuclei are masses located deep within white matter. White matter (inner part) consists of long myelinated axons organized into tracts. The two hemispheres are connected by the corpus callosum. 5 Lobes of Cerebral Hemisphere 6 7 8 Basal Nuclei These basal nuclei integrate motor commands to ensure that the proper muscle groups are stimulated or inhibited. Integration ensures that movements are coordinated and smooth 9 0068 10 The Brain Diencephalon is made up of hypothalamus and thalamus, and circles the third ventricle-integrating center that helps maintain homeostasis. Cerebellum is separated from the brain stem by the fourth ventricle. 2’nd largest part, involved in muscle coordination, tone, and maintaining posture/balance. The brain stem contains the midbrain, pons, and medulla oblongata. Connects cerebrum with other brain parts; regulate breathing; reflex movements for head to respond to visual, auditory stimuli; centers for heartbeat, respiration, vasoconstriction (blood pressure) etc. 11 Reticular Activating System (RAS) Reticular formation is a complex network of nuclei and fibers extending the length of the brain stem. Involves the thalamus serves as a central relay station for sensory impulses (except smell) acts as a “gatekeeper” to the cerebrum. The RAS arouses the cerebrum via the thalamus and causes a person to be alert. If you want to awaken the RAS. 12 Reticular Activating System 13 The Limbic System and Higher Mental Functions Limbic system is a complex network of tracts and nuclei. Blends primitive emotions and higher mental functions into a united whole. Composed of hippocampus (crucial role in learning and memory) and amygdala (emotional overtones to experiences). “Good and bad feelings”. It is the emotional brain. Involved in emotions (rage, pain, etc.), learning, and memory. 14 Limbic System 15 Higher Mental Functions Memory and Learning Memory is the ability to hold a thought in mind or to recall events from the past. Learning takes place when we retain and utilize past memories. Types of Memory: Short-term versus long-term - is a mixture of... Semantic memory – numbers, words, etc. Episodic memory – persons, events, etc. Skill memory - can exist independent of episodic memory, involves performing motor activities (ie. riding a bike, playing a sport, etc.), initially conscious while learning but automatic once learned. 16 Higher Mental Functions Language and Speech Depends on semantic memory and motor centers in the occipital and temporal lobes. Wernicke’s area – ability to comprehend speech. Broca’s area – ability to speak and write. The visual cortex, Wernicke’s area and Broca’s area must all function together..... 17 Language and Speech 18 Language and Speech 19 Language and Speech In a very general way, left and right brain have different functions. Left Hemisphere: Verbal, Logical, analytical, Rational. Right Hemisphere: Nonverbal, visuospacial, Intuitive, Creative. Researchers believe hemispheres process the same information differently – - left is more global, - right is more specific in approach. 20 EEG’s ?  electro/encephalo/gram// records brain’s electrical activity.  subject awake with eyes closed – alpha waves.  if eyes open – beta waves.  during sleep, REM (rapid eye movement) – theta waves.  Deep sleep – delta waves. 21 0066 22 The Peripheral Nervous System Composed of nerves and ganglia. Cranial nerves take impulses to and from the brain. (12 prs.) Spinal nerves take impulses to and from the spinal cord. (31prs.) 23 Cranial and Spinal Nerves 24 Somatic System Somatic system includes nerves that take sensory information from external sensory receptors to the CNS and motor commands away from the CNS to the skeletal muscles. Primarily voluntary. The exception is..... Reflexes are automatic, involuntary responses to a stimulus. What are its component parts? 25 Reflex Arc 26 Reflex Arc 27 Autonomic System Autonomic system regulates the activity of cardiac and smooth muscles and glands. Is involuntary. 2 component parts: Sympathetic division brings about “fight or flight” responses. (norepinephrine) Parasympathetic division brings about relaxed responses or “housekeeper system”. (acetycholine) 28 Autonomic System 29 30 31 32