The Central Nervous System

1. UNIT B Chapter 12: Nervous System Section 12.3 Receives sensory information and initiates motor control Composed of the spinal cord and the brain. Brain: controls breathing, heart rate, body temperature, blood pressure, emotions, reasoning, memory, and creativity Spinal cord: a means of communication between the brain and the peripheral nerves that leave the cord The Central Nervous System TO PREVIOUS SLIDE

2. UNIT B Chapter 12: Nervous System Section 12.3 Figure 12.7 Organization of the nervous system. The CNS is composed of the spinal cord and brain. The PNS is composed of the motor and sensory pathways. TO PREVIOUS SLIDE

3. Brain and Spinal Cord both: • Contain gray matter (cell bodies and short, nonmyelinated fibers) and white matter (myelinated axons that run in tracts), • protected by bone, • wrapped in protective membranes called meninges, • surrounded and cushioned with cerebrospinal fluid that is produced in the ventricles of the brain. • Composed of gray and white matter

4. Nerve - a whitish bundle of nerve fibers (axons)

6. Cerebral Spinal Fluid (CSF) • Produced by ventricles (hollow cavities)and the spinal cord’s central canal • Cushions the brain to prevent injury • Removes waste products of the brain's metabolism • Maintains a constant pressure within the brain — compensating for changes in blood pressure in the brain • Improper drainage  hydrocephalus

7. UNIT B Chapter 12: Nervous System Section 12.3 Structure Individual vertebra protect the spinal cord Spinal nerves project from the cord between the vertebrae in the vertebral column Fluid-filled intervertebral disks cushion and separate the vertebrae The Spinal Cord Figure 12.8 Spinal cord. a. The spinal cord passes through the vertebral canal formed by the vertebrae. TO PREVIOUS SLIDE

8. Herniated Disk

11. UNIT B Chapter 12: Nervous System Section 12.3 Central canal: contains cerebrospinal fluid Grey matter: inner “H” parts of sensory, motor, and interneurons Dorsal root: sensory fibres entering grey matter Ventral root: motor fibres exiting grey matter Spinal nerves: part of PNS TO PREVIOUS SLIDE

12. UNIT B Chapter 12: Nervous System Section 12.3 White matter: ascending tracts take information to the brain, dorsal descending tracts take information from the brain and are ventral Tracts cross each other after entering and exiting CNS Left side of brain: controls right side of body Right side of brain: controls left side of body TO PREVIOUS SLIDE

13. UNIT B Chapter 12: Nervous System Section 12.3 Functions of the Spinal Cord Communication between Brain and PNS Example: Voluntary movement When we move our limbs, motor impulses in the brain pass down descending tracts to the spinal cord and out to our muscles through motor fibres Center for Reflex Arcs- Involuntary and nearly instantaneous movement in response to a stimulus. TO PREVIOUS SLIDE

14. Take on line Quiz • https://highered.mheducation.com/sites/0072351136/student_view0/chapter12/chapter_quiz.html

15. CNS • Crash course: CNS • https://www.youtube.com/watch?v=q8NtmDrb_qo

16. The human brain

17. UNIT B Chapter 12: Nervous System Section 12.3 Figure 12.9 The human brain. a. The cerebrum, seen here in longitudinal section, is the largest part of the brain in humans. The right cerebral hemisphere is shown here. TO PREVIOUS SLIDE

18. Brain has 4 ventricles

19. UNIT B Chapter 12: Nervous System Section 12.3 All have primary function and adjacent association areas that integrate signals The Brain has 4 main parts TO PREVIOUS SLIDE

21. Forebrain – highest, differentiates humans from animals (Telencephalon, Diencephalon) • Cerebral Cortex • Thalamus – on top of brain stem; sorts and relays incoming info to appropriate forebrain areas (cerebellum to motor cortex). Also works with Retic Formation on reg sleep and wakefulness • Hypothalamus – below thalamus. Monitors pleasurable activties (eating, drinking, sex). Influences endocrine system, esp pituitary in response to emotions, stress and rewards. • Basal Ganglia –cluster of neurons b/t thalamus and cortex, works with cortex and cerebellum for coordinating voluntary movements and habitual behaviours (cycling, typing) • Limbic System – Amygdala (processes emotions) and hippocampus (memory storage)

22. UNIT B Chapter 12: Nervous System Section 12.3 largest part of the brain in humans Communicates with and coordinates activities of other parts of the brain Higher thought processes (learning, memory, language, speech. The Cerebrum (Telencphalon) TO PREVIOUS SLIDE

23. UNIT B Chapter 12: Nervous System Section 12.3 Structure and Function Cerebrum Two cerebralhemispheres communicate via the corpus callosum, a bridge of nerve tracts. The cerebral cortex is a thin outer layer of grey matter covering the cerebral hemispheres Grooves called sulci divide the hemisphere into four lobes: frontal, parietal, occipital, temporal Gyri – bumps TO PREVIOUS SLIDE

24. The lobes of a cerebral hemisphere

25. UNIT B Chapter 12: Nervous System Section 12.3 Frontal Lobe of Cerebral Cortex Primary motor area: involved in voluntary movement Premotor area: organizes motor functions and sends signals to cerebellum for integration Prefrontal area: processing centre involved in reasoning and planning (appropriate behaviour) Broca’s area: involved in speech musculature (lips, tongue, larynx) TO PREVIOUS SLIDE

26. UNIT B Chapter 12: Nervous System Section 12.3 Parietal Lobe (dorsal to central sulcus) Primary somatosensory area: involved in somatic sensing Primary taste area: involved in taste Somatosensory association area: processes and analyzes sensory information from skin and muscles TO PREVIOUS SLIDE

27. UNIT B Chapter 12: Nervous System Section 12.3 Temporal Lobe Primary auditory area: involved in hearing Auditory association area: associates new audio information with previous audio information Wernicke’sarea: helps us understand written and spoken words TO PREVIOUS SLIDE

28. UNIT B Chapter 12: Nervous System Section 12.3 Occipital Lobe Primary visual area: involved in vision Visual association area: associates new visual information with previous visual information (e.g., facial recognition) TO PREVIOUS SLIDE

29. UNIT B Chapter 12: Nervous System Section 12.3 12.11 The primary motor and somatosensory areas. In these drawings, the size of the body part reflects the amount of cerebral cortex devoted to that body part. For example, the amount of primary motor cortex (a) and somatosensory cortex (b) devoted to the thumb, fingers, and hand is greater than that for the foot and toes. TO PREVIOUS SLIDE

30. Homunculus

31. UNIT B Chapter 12: Nervous System Section 12.3 Central White Matter consists mostly of long myelinated axons forming tracts; cross over so the left side of the brain handles right side information. Most of the cerebrum beneath the cerebral cortex is composed of white matter TO PREVIOUS SLIDE

32. Basal Ganglia • masses of grey matter located • deep within the white matter of the • cerebrum • Integrate motor commands to • ensure proper muscle groups are • activated or inhibited • Habitual behaviour such as typing or biking

33. Gray and White Matter

34. UNIT B Chapter 12: Nervous System Section 12.3 Hypothalamus and thalamus, pineal gland, third ventricle The Diencephalon TO PREVIOUS SLIDE

35. UNIT B Chapter 12: Nervous System Section 12.3 Hypothalamus Integrating centre that helps maintain homeostasis Regulates hunger, sleep, thirst, body temperature, and water balance, pleasure and pain, satisfaction, anger and aggressive behavior Controls the pituitary gland: a link between the nervous and endocrine systems TO PREVIOUS SLIDE

36. UNIT B Chapter 12: Nervous System Section 12.3 Thalamus Two masses of grey matter that receive all sensory input except smell Integrates visual, auditory, taste, and somatosensory information from spinal cord and sends it to the appropriate area in the cerebrum Involved in higher mental functions (memory, emotions) Pineal gland Secretes the hormone melatonin, which is involved in maintaining a normal sleep-wake cycle TO PREVIOUS SLIDE

37. Limbic system

38. Controls our Emotions Blends primitive emotions and higher mental functions, such as learning and formation of memories. amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, and cingulate gyrus. hippocampus and amygdala are essential for learning and memory. The Limbic System

39. Amygdala • Responsible for the response and memory of emotions, especially fear 

40. Hippocampus • Role in the formation of new memories about past experiences. • Responsible for processing of long term memory and emotional responses. • Prefontal area consults hippocampus in order or use memories to modify behaviour.

41. Check your progress • 1. The ________ lobe contains the visual cortex. • A) frontal • B) parietal • C) temporal • D) Occipital • 2. The ________ connects the two cerebral hemispheres. • A) limbic system • B) corpus callosum • C) cerebellum • D) pituitary

42. 3. Neurons in the ________ control motor reflexes. • A) thalamus • B) spinal cord • C) parietal lobe • D) Hippocampus • 4. What methods can be used to determine the function of a particular brain region? • 5. What are the main functions of the spinal cord?

43. UNIT B Chapter 12: Nervous System Section 12.3 Contains the midbrain and hind brain (pons, and medulla oblongata, cerebellum) The Brain Stem TO PREVIOUS SLIDE

44. Mid brain (mesencephalon) • Relays info between hind brain and forebrain • Has reflex centres for visual, auditory, and tactile responses • 2 systems: • 1. Reticular Formation – involved in patterns of behaviour such as walking, sleeping and other reflexes • 2. Cluster of neurons with dopamine, serotonin, NE receptors,

45. Reticular Formation • Reticular activating system (RAS) • Complex network of nuclei and fibers that extend the length of the brain. • Arouses cerebrum via the • thalamus causing alertness. • Also involved in filtering • out unnecessary sensory • stimuli (e.g., studying while • the TV is on) • Inactive RAS causes sleep

47. Hind brain – brain stem, most ancient (Metencephalon, Myencephalon) • Medulla Oblongata – breathing, other reflexes • Cerebellum – coordinated motor movement • Pons - cluster of neural fibres, bridge to midbrain, surrounding reticular formation, monitors sleep and arousal in autonomic • Involved in alertness and in monitoring basic survival functions such as breathing, heartbeat, and blood pressure. It is also known as the "reptilian brain" because it is considered the entire brain of reptiles.

48. Medulla oblongata (Myencephalon) • Regulates heartbeat, breathing, and blood pressure • Contains reflex centres for vomiting, coughing, sneezing, hiccupping, and swallowing

49. UNIT B Chapter 12: Nervous System Section 12.3 The cerebellum is located under the occipital lobe of the cerebrum. The Cerebellum (metencephalon) TO PREVIOUS SLIDE

50. UNIT B Chapter 12: Nervous System Section 12.3 Two portions: white matter covered by thin layer of grey matter Involved in maintaining posture and balance Receives sensory input from eyes, ears, joints, muscles, and other sensory pathways about the position of body parts Receives motor output from the cerebral cortex about where body parts should be located Involved in producing smooth, coordinated voluntary movements (e.g., playing piano, hitting a baseball) Learning new motor skills (playing piano). Cerebellum Structure and Function TO PREVIOUS SLIDE