BIO 210 CHAPTER 13. The Central Nervous System SUPPLEMENT 2. PowerPoint by John McGill Supplemental Notes by Beth Wyatt CEREBELLUM

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1 BIO 210 CHAPTER 13 The Central Nervous System SUPPLEMENT 2 PowerPoint by John McGill Supplemental Notes by Beth Wyatt CEREBELLUM Second Largest Division of the Brain Lies Below the Posterior Portion of the Cerebrum 1

2 CEREBELLUM Second Largest Division of the Brain Lies Below the Posterior Portion of the Cerebrum CEREBELLUM: Transverse Fissure OCCIPITAL LOBE CEREBELLUM Horizontal Groove that Separates the Cerebrum from the Cerebellum 2

3 CEREBELLUM: CEREBELLAR HEMISPHERES The 2 Halves of the Cerebellum that are Joined CEREBELLUM: VERMIS The Central Portion of the Cerebellum Joins the 2 Cerebellar Hemispheres 3

4 Sheep Brain A- sagittal fissure B - central sulcus C - frontal lobe D - parietal lobe E - occipital lobe F - temporal lobe G - cerebellum H - vermis I - medulla CEREBELLUM: Convolutions Folds/ridges 4

5 CEREBELLUM: CONVOLUTIONS CEREBELLUM: SULCI Grooves 5

6 CEREBELLUM: SULCI CEREBELLUM: Gray & White Matter Arbor Vitae: Tree of Life Centrally Located White Matter of Cerebellum 6

7 ARBOR VITAE CEREBELLUM: Gray & White Matter Cerebellar Cortex Peripherally Located Gray Matter 7

8 1. Arbor vitae (of cerebellum) 2. Corpus callosum 3. Fornix 4. Optic chiasma 5. Hypothalamus 6. Mammillary body 7. Lateral ventricle 8. Thalamus 9. Pineal body 10. Tectum 11. Cerebral aqueduct 12. Pons 13. Medulla oblongata 14. Spinal cord 15. Anterior commissure 16. Corpora quadrigemina Sheep Brain CEREBELLUM: Peduncles CEREBELLAR PEDUNCLES INFERIOR, MIDDLE, SUPERIOR Tracts that Connect Cerebellum to Other Parts of CNS (Primarily to Brainstem) 8

9 Cerebellum Picture FUNCTIONS of the CEREBELLUM All Functions of Cerebellum Involve Skeletal Muscles SKILLED MOVEMENTS (WITH CEREBRAL CORTEX) Nerve Impulses from the Cerebellum Added to Nerve Impulses from the Cerebral Cortex Produce Movements (Skeletal Muscles) That are Coordinated and Precise EQUILIBRIUM Cerebellum Works with the Inner Ear and Skeletal Muscles to Help Maintain Balance POSTURE Cerebellum Controls Tonic Contractions 9

10 DIENCEPHALON Between Brain 3 MAJOR STRUCTURES THALAMUS HYPOTHALAMUS PINEAL BODY DIENCEPHALON: THALAMUS Gray Matter Shaped Like a Dumb-bell Weight 10

11 DIENCEPHALON: HYPOTHALAMUS Gray Matter Below Thalamus Boundaries: Anterior Portion: Optic Chiasma Middle Portion: Infundibulum Posterior Portion: Mamillary Bodies Sheep HYPOTHALAMUS (#9) Optic Chiasma Mammilary Body Pituitary Gland 11

12 PINEAL BODY Pine-cone Shaped Structure Located Above the Corpora Quadrigemina Sheep Pineal 12

13 Functions of the Diencephalon THALAMUS SENSATIONS (TWO PART MECHANISM) SERVES AS A MAJOR RELAY STATION FOR SENSORY IMPULSES HEADED TO THE CEREBRAL CORTEX PRODUCES CRUDE AWARENESS OF SOME GENERAL SENSATIONS Functions of the Diencephalon: Thalamus SENSATIONS: MAJOR RELAY STATION FOR SENSORY IMPULSES HEADED TO THE CEREBRAL CORTEX Impulses That Will Eventually Reach the Cerebral Cortex and be Interpreted as Sensations* are First Relayed Through the Thalamus (Thalamus is the "Gateway to the Cerebral Cortex") * All Sensations Except for Possibly Olfactory 13

14 Functions of the Diencephalon: Thalamus PRODUCES CRUDE AWARENESS OF SOME GENERAL SENSATIONS Crude Awareness: Not Precise/Fine Tuned Cerebral Cortex Interprets Sensations; However, the Thalamus can Interpret Some General Sensations, but Only on a Crude Level Functions of the Diencephalon continued ASSOCIATION OF SENSATIONS WITH EMOTIONS Thalamus Allows Us to Link Sensations (i.e., Taste) with Emotions (i.e., Unpleasantness) AROUSAL (ALERTING MECHANISM) Thalamus (as Well as Many Other Areas of the Brain) is Involved in Keeping Us Awake and Alert (Consciousness) COMPLEX REFLEX MOVEMENTS The Thalamus is Involved in Some Reflexes 14

15 HYPOTHALAMUS REGULATES/CO-ORDINATES ANS There are Neuron Connections Between the Hypothalamus and the ANS LINKS "PSYCHE" AND "SOMA" Psyche: Mind/Awareness; Associated with the Cerebral Cortex Soma: Body/Effectors; Associated with the ANS and the Somatic NS Helps to Explain Psychosomatic Illness (Emotions can Lead to Changed Body Functions) HYPOTHALAMUS controls PITUITARY GLAND LINKS NERVOUS AND ENDOCRINE SYSTEMS (CONTROLS PITUITARY GLAND) DIRECTLY: SYNTHESIZES POSTERIOR PITUITARY GLAND HORMONES (WATER BALANCE) INDIRECTLY: REGULATES HORMONE SECRETION BY ANTERIOR PITUITARY GLAND (RELEASING HORMONES) 15

16 HYPOTHALAMUS & Posterior Pituitary Gland DIRECTLY: SYNTHESIZES POSTERIOR PITUITARY GLAND HORMONES (WATER BALANCE) The Hypothalamus Actually Builds the Hormones of the PPG; PPG Just Stores and Releases Them HYPOTHALAMUS & Anterior Pituitary Gland INDIRECTLY: REGULATES HORMONE SECRETION BY ANTERIOR PITUITARY GLAND (RELEASING HORMONES) The APG Builds Its Own Hormones; However, Those Hormones Aren't Released Until the Hypothalamus "Says" They can be Released 16

17 RELEASING HORMONE PATHWAYS The Way the Hypothalamus "Says" These Hormones can be Released is Through Releasing Hormones i.e., Hypothalamus -----> Releasing Hormones -----> APG -----> Release of APG Hormones HYPOTHALAMUS: Overall Functions AROUSAL (ALERTING) MECHANISM REGULATES APPETITE AND FOOD INTAKE REGULATION OF BODY TEMPERATURE 17

18 HYPOTHALAMUS: Alertness AROUSAL (ALERTING) MECHANISM The Hypothalamus is Also Involved in This Mechanism HYPOTHALAMUS: Appetite REGULATES APPETITE AND FOOD INTAKE The Hypothalamus Contains Both Appetite and Satiety Centers (Clusters of Neurons) When the Appetite Center is Stimulated, One Feels Hungry, When the Satiety is Stimulated, One Feels Full 18

19 HYPOTHALAMUS: Body Temperature REGULATION OF BODY TEMPERATURE The Hypothalamus Contains the Human Thermostat PINEAL BODY REGULATES BIOLOGICAL CLOCK Individual's Unique Patterns of Eating and Sleeping; Also Includes Cycles That Occur in the Female Reproductive System SECRETES HORMONES (MELATONIN) For This Reason, is Also Known as the Pineal Gland Secretes Melatonin 19