afferent efferent contralateral ipsilateral

Transcription

1 Neuroanatomy 1

2 A Typical Neuron 2

3 3

4 4

5 afferent efferent contralateral ipsilateral 5

6 special case: midsagittal Planes of Section Frontal Sagittal Horizontal 6

7 Some basic terms in neuroanatomy central nervous system (CNS) = brain + spinal cord peripheral nervous system (PNS) = cranial nerves + spinal nerves + peripheral ganglia nucleus - a local collection of cell bodies in the CNS ganglion - a local collection of cell bodies in the PNS (exception: basal ganglia) tract - a bundle of axons in the CNS nerve - a bundle of axons in the PNS gray matter - areas where there are lots of cell bodies in the CNS appear grayish in color white matter - areas where there are lots of myelinated axons in the CNS appear white in color 7

8 Naming conventions for tracts begins with the location of the cell bodies and ends with the location of the terminal buttons (e.g. spinothalamic, corticospinal, spinocerebellar) prominent tracts may retain their old names: e.g., fornix, pyramidal tract other names for tracts: fasciculus, capsule, commissure, lemniscus, peduncle (used in special cases) 8

9 Development three cell layers of the embryo: ectoderm, mesoderm, endoderm the nervous system (and skin) forms from the ectoderm 9

10 Development a neural plate forms and gradually folds into a neural tube lots of things can go wrong 10

11 Development anencephaly - missing cerebral hemispheres when the cephalic (head) end of the neural tube fails to close micro(en)cephaly - zika (a mosquito borne virus) 11

12 Development myeloschisis - abnormal formation of the spinal cord spina bifida being one of the milder forms (lower spine and spinal cord, generally) 12

13 Development eventually, the developing nervous system becomes roughly segmented into six regions telencephalon -cerebral hemispheres diencephalon - thalamus and hypothalamus mesencephalon - midbrain metencephalon - pons and cerebellum myelencephalon - medulla spinal cord 13

14 14

15 15

16 16

17 Cerebrospinal Fluid (CSF) fills the ventricles and subarachnoid space produced in the choroid plexus in lateral and 3rd ventricles about 125 milliliters (or 1/2 cup) circulation - lateral v., interventricular foramen, third v., cerebral aqueduct, fourth v., then through three small foramens into the subarachnoid space cushioning and bouyancy function 17

18 Hydrocephalus water on the brain blockage of one of the smaller foramens or aqueducts can result in build-up of CSF behind the block the blockage is usually in the cerebral aqueduct this can happen in adults, too! 18

19 19

20 blood is drained away via sinuses embedded in the dura, and eventually via the jugular vein 20

21 Energy Needs of the Brain consumes about 20% of oxygen carried in the blood (even though it is only about 2% of adult body weight, about 3 lbs.) requires about 400 Calories per day (all in carbohydrates) - burns 15 watts more or less continuously when the body is at rest, it is the most expensive tissue in the body to maintain 21

22 Telencephalon 22

23 precentral gyrus precentral sulcus central fissure postcentral gyrus postcentral sulcus cerebellum superior temporal gyrus lateral fissure brainstem 23

24 Lobes of the Cerebral Hemispheres 24

25 Kinds of Cortex: primary sensory, sensory association, primary motor, secondary motor 25

26 Structure of Cortex neocortex six-layered cortex input layers output layers etc. 26

27 (anterior) cingulate gyrus (limbic cortex) corpus callosum cingulate sulcus anterior commissure brainstem cerebellum 27

28 Temporal lobe Frontal lobe Brainstem Cerebellum cranial nerves 28

29 Limbic System 29

30 Basal Ganglia 30

31 31

32 32

33 33

34 Diencephalon 34

35 35

36 Nuclei of the Thalamus 36

37 37

38 The Lower Brainstem mesencephalon metencephalon myelencephalon 38

39 mesencephalon (myelin stain) superior colliculi tectum periaqueductal gray tegmentum (red nuc.) pyramidal tract cranial nerve nuc. (III) substantia nigra cerebral peduncle (crus cerebri) 39

40 metencephalon (myelin stain) cerebellum cranial nerve nuc. (VII) 4th ventricle pyramidal tract middle cerebellar peduncle 40

41 41

42 myelencephalon (myelin stain) cranial nerve nuc. (XII) somatosensory nuc. inferior olive pyramids (pyramidal tracts) 42

43 Decussation of the pyramidal (corticospinal) tract 43

44 44

45 Spinal Cord 45

46 spinal cord (myelin stain) ascending sensory tracts (fine touch) dorsal horn (sensory afferents) ventral horn (motor efferents) 46

47 Somatosensory System (fine touch) 47

48 48

49 49

50 50

51 Spinal Nerves (more or less) 51

52 cranial nerves 52

53 53

54 cranial nerve I: olfactory nerve 54

55 cranial nerve II: optic nerve 55

56 56

57 cranial nerves III, IV, and VI: eye movement 57

58 cranial nerve V: trigeminal nerve 58

59 Trigeminal neuralgia or Tic douloureux 59

60 cranial nerve VII: facial nerve 60

61 61

62 cranial nerve VIII: auditory nerve (and many other names!) 62

63 auditory system 63

64 The End 64