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The Central Nervous System. CNS –CNS: brain and spinal cord –Necessary for the maintenance of homeostasis –Contains 10 11 neurons –Contains 10 14 synapses.

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Presentation on theme: "The Central Nervous System. CNS –CNS: brain and spinal cord –Necessary for the maintenance of homeostasis –Contains 10 11 neurons –Contains 10 14 synapses."— Presentation transcript:

1 The Central Nervous System

2 CNS –CNS: brain and spinal cord –Necessary for the maintenance of homeostasis –Contains 10 11 neurons –Contains 10 14 synapses –Responsible for everything we perceive, do, feel, and think

3 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

4 Cerebrum Five paired lobes within two hemispheres Gray matter in cortex and in deeper cerebral nuclei White matter inside Higher functions are performed by the brain

5 Brain matter What is gray and white matter? Gray matter: neurons and unmyelinated axons White matter: myelinated axons

6

7 Protection and Coverings Cranial bones Meninges - 3 layers: - Dura mater, Arachnoid, and pia mater -Between dura mater and arachnoid: subdural space -In between arachnoid and pia mater, in subarachnoid space: cerebro-spinal fluid (CSF)

8 Meninges

9

10 Meningitis

11 CSF Cushion the brain Provide a constant IF environment About 150 ml Produced by the ependymal cells of the choroid plexus, in the ventricle Resorbed by the arachnoid granulations Continuously produced and continuously resorbed Composition slightly different from plasma

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13 Cerebrospinal fluid circulation

14 CSF circulation

15 Hydrocephalus A blockage of CSF circulation will trigger an accumulation of CSF in the ventricle This will result in hydrocephalus

16 Hydrocephalus

17 Blood supply –CNS comprises 2% of body weight (3–4 pounds) Receives 15% of blood supply –High metabolic rate Brain uses 20% of oxygen consumed by body at rest Brain uses 50% of glucose consumed by body at rest –Depends on blood flow for energy

18 Energy supplies –Depends on aerobic glycolysis –Requires glucose and oxygen –No glycogen stores –Fatty acids not used for energy –Ketones used during extreme conditions

19 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

20 Brain structure

21 Cerebrum Two hemispheres Surface have gyri, grooves(sulci) and fissures Two fissures: longitudinal (falx cerebri and cerebelli) and transverse (tentorium cerebelli) Corpus callosum

22 Cerebrum Cerebral cortex - Lobes: 1 frontal, 1 parietal, 1 occipital, and 2 temporal and insula – surface is gray matter - Basal nuclei (or ganglia)- gray matter deep inside white matter.

23 Frontal lobe Voluntary motor control Personality Concentration, planning, decision making Verbal communication

24 Frontal lobe : Motor area

25 Language Broca’s aphasia: due to damage in the Broca’s area of the brain. Speech slow and poorly articulated Wenicke’s aphasia: due to damages to Wernicke’s area produces a rapid speech without meaning. Comprehension destroyed

26 Speech areas

27 Parietal lobes Sensory interpretations Understanding speech Formulating words to express thoughts and emotions Interpretations of textures and shapes

28 Sensory areas

29 “Small brain”

30 Temporal lobes Interpretation of auditory sensations Memory of auditory and visual experiences

31 Occipital lobe Perception of vision Vision recognition Focusing and eye movement

32 Memory Short and long term memory Several regions of the brain involved, especially temporal lobe, hyppocampus Short  long term memory: medial temporal lobe Long term memory independent of temporal lobe Memory acquisition possible due to synapse changes

33

34 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

35 Basal Nuclei Mass of neurons located deep into the white matter Help control of voluntary movement

36 Basal Nuclei

37 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

38 Diencephalon

39 Thalamus:4/5 of diencephalon Below lateral ventricles Relay center through which sensory informations (except smell) pass, on the way to the cortex Many nuclei

40 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

41 Diencephalon: Hypothalamus and pituitary gland Below thalamus Neural centers for many functions: - hunger, thirst, body temperature regulation - controls pituitary gland - contribute to sleep regulation, emotions (fear, anger, pain, pleasure..), sexual arousal

42 Hypothalamus

43 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

44 Midbrain Between diencephalon and pons Several nuclei: - corpora quadrigemina: visual and auditory reflexes - red nucleus: motor coordination - nigrostriatal system (from substancia nigra- basal ganglia)  motor coordination (involved in Parkinson’s disease) - cerebral peduncles: ascending and descending fiber tracts

45 Midbrain

46 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

47 Pons Between midbrain and medulla oblongata Several nuclei associated with cranial nerves (V, VI, VII, and VIII) Respiratory centers: apneustic and pneumotaxic centers Communicates with cerebellum and medulla oblongata, and midbrain

48 Pons

49 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

50 Medulla oblongata Between pons and spinal cors Numerous nuclei controlling cranial nerves (VIII,IX,X,XI, and XII), and vital functions: vasomotor, cardiac, respiratory, sneezing, swallowing centers Passageway for sensory and motor fibers Fibers “decussate” or cross over

51 Medulla oblongata

52 Cerebral lateralization The cerebral cortex controls movement of the contralateral side Sensations project to the contralateral side of the parietal lobes The two hemispheres communicate through the corpus callosum Left side: language and analysis Right side: visual spatial tasks

53 Medulla oblongata

54 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

55 Limbic system Emotion & motivation Mesh of neurons around the brain Connect to hypothalamus Involved in control of: - aggression, fear, feeding, sex and goal- directed behavior

56 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

57 Reticular formation Complex network of nuclei and nerve fibers in medula, pons, midbrain, diencephalon Reticular Activating System (RAS): maintain a state of alert consciousness

58 The Brain BRAIN MATTER AND CEREBROSPINAL FLUID CEREBRUM a- Cerebral hemispheres a1- Lobes a2- Basal ganglia (nuclei) b- Brain stem b1-Diencephalon b1-1- Thalamus b1-2- Hypothalamus b2- Midbrain b3- Pons b4- Medulla oblongata c- Limbic system d- Reticular formation CEREBELLUM

59 Cerebellum “small brain” Fibers from cerebellum  red nucleus  thalamus  cerebral cortex Other tracts connect cerebellum to pons, midbrain, medulla Receives input from proprioreceptors (from muscles, tendon)  coordinates movement, control equilibrium

60 Cerebellum

61 Readings Chp. 9, p. 216-236 Not expected to be known:


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