1. Nervous System-Anatomy

2. Central Nervous System
Brain
Spinal Cord
(also includes 4 chambers in brain called ventricles)

3. Brain 1) Cerebral Hemispheres 2) Diencephalon 3) Brain Stem
4) Cerebellum

5. 1) Cerebral Hemispheres
Covered by ridges = gyri
Ridges separated by grooves = sulci
The hemispheres (right and left) are separated by a single deep longitudinal fissure
Other shallow fissures divide each hemisphere into lobes
Lobes are named for the cranial bones over them

7. Ear to ear is the central fissure (sulci)
Posterior to the central fissure in the parietal lobe is the somatic sensory area (post central gyri)
Impulses that travel from sensory receptors are interpreted there
Crossed pathways

9. Anterior to the central fissure in the frontal lobes is the primary motor area (Pre central gyri)
Allows us to consciously move our skeletal muscles
Major voluntary motor tract that descends to the spinal cord
Crossed pathways

11. Impulses for special senses: Visual = posterior occipital
Areas in Cerebrum
Impulses for special senses:
Visual = posterior occipital
Auditory = temporal lobe (lateral fissure)
Olfactory = deep temporal lobe

13. Impulses for the special senses:
Broca’s area = base of the pre-central gyrus located in left hemisphere only, gives ability to say words properly
Speech Area = junction of temporal, parietal, and occipital lobes, allows understanding of words, spoken or read and response to them

14. Higher Reasoning = anterior frontal lobe
Complex Memories = temporal and frontal lobes

15. Gray matter – of cerebral hemispheres contain the cell bodies of neurons
White matter – of cerebral hemispheres is composed of fiber tracts which carry impulses to or from the cortex

16. Corpus callosum – a very large fiber tract that connects the cerebral hemispheres and allow left and right brain to communicate
Basal nuclei or basal ganglia are buried within the white matter and help regulate voluntary motor activities

18. Thalamus- encloses the 3rd ventricle, relay for sensory impulses
2) Diencephalon
Interbrain:
Thalamus- encloses the 3rd ventricle, relay for sensory impulses

19. Hypothalamus- floor of diencephalon, autonomic center.
Functions: regulates body temperature, water balance, and metabolism, contains the “limbic system” which is a center for many drives; thirst, appetite, sex, pleasure,
-Regulates the pituitary gland, contains mammillary bodies

20. Epithalmus- forms the roof of the 3rd ventricle, contains pineal body (endocrine gland), contains:
Choroid plexus which forms CSF (cerebral spinal fluid)

22. 3) Brain Stem
Midbrain- extends from the mammillary bodies (in diencephalon) to the pons
Cerebral aqueduct- connects 3rd ventricle to 4th ventricle
Corpora Quadrigemina- four rounded protrusions – reflex centers for vision and hearing

25. Pons- just below midbrain, mostly fiber tracts, important for control of breathing
Medulla Oblongata- most inferior part of brain stem, merges with spinal cord, mostly fiber tracts.
Functions-controls heart rate, blood pressure, breathing, swallowing, vomiting. 4th ventricle is posterior

26. 4) Cerebellum
Coordinates skeletal muscle activity, controls balance and equilibrium, monitors body position

27. Protection of the Brain
Skull
Meninges- 3 parts:
Dura Mater- outside tough layer
Arachnoid Mater- middle blood vessels
Pia Mater- surface of the brain layer
3) Cerebral Spinal Fluid- CSF continuously formed by choroid plexus , cushions, protects, runs down central canal of the spinal cord

30. Problems of the Brain Concussion -MS Contusion -ALS
Aneurysm -Huntington’s
CVA (cerebrovascular attack), aphasia (difficulty speaking), paralysis
TIA (transient ischemic attack)
Alzheimer’s disease
Parkinson’s disease

31. Reflex center and 2 way conduction pathway Central canal contains CSF
Spinal Cord
17 inches from skull to L2
Reflex center and 2 way conduction pathway
Central canal contains CSF

33. Gray Matter of Spinal Cord
Dorsal Horns (posterior)- contains interneurons and sensory neurons; enter by dorsal root (ganglion)
Ventral Horns (anterior)- contain motor neurons, (somatic voluntary), leave by the ventral root
The dorsal and ventral roots fuse to form the spinal nerves

35. White Matter of Spinal Cord
Myelinated fiber tracts, some run to other side of spinal cord, some run to higher centers
All tracts in the anterior and lateral cord are motor
All tracts in the posterior cord are sensory

36. Problems of the Spinal Cord
Dorsal root damage- sensory damage = parasthesis
Ventral root damage- motor damage = paralysis

37. Peripheral Nervous System
Contains nerves: spinal and cranial
A nerve is a bundle of neurons found outside the CNS
Nerves are neurons bundled in connective tissue

38. Nerves are named like neurons:
Carry to CNS= afferent
Carry from CNS= efferent
Carrying both sensory and motor= mixed (all spinal)

40. Cranial Nerves- 12 pair
1. olfactory- sensory
2. optic- sensory
3. oculomotor- motor
4. trochlear- motor
5. trigeminal- mixed
6. abducens- motor

41. 7. facial- mixed
8. vestibulocochlear- sensory
9. glossopharyngeal- mixed
10. vagus- mixed
11. accessory- mostly motor
12. hypoglossal- mixed

43. Spinal Nerves – 31 pairs
Formed from the fusion of the ventral and dorsal roots of the spinal cord
Divides into dorsal and ventral rami
Both types of rami contain both sensory and motor nerves , just go to different places

45. Dorsal rami are smaller and serve skin and muscle of posterior body trunk
Ventral rami of T1- T12 form intercostal nerves
All other ventral rami form plexuses which serve limbs, neck, and diaphragm

47. 4 Plexus Origin Plexus Serves C1 – C4 Cervical Phrenic C5 – C8
Major Nerve
Serves
C1 – C4
Cervical
Phrenic
diaphragm
C5 – C8
Brachial
Axillary
Arm
T12 , L1 – L4
Lumbar
Femoral
Lower abs, butt
L4 –L5 ,
S1 – S4
Sacral
Sciatic
Post leg

50. Two Divisions of the Peripheral Motor Nervous System
Somatic Nervous System
Autonomic Nervous System

51. Somatic Nervous System
One neuron extends to skeletal muscle
Voluntary

52. Autonomic Nervous System
Involuntary, Automatic
Motor control of cardiac muscle, smooth muscle, and glands
Involves a chain of two motor neurons called: pre ganglion and post ganglion

53. Autonomic Nervous System has two arms:
Parasympathetic- rest and digest / homeostasis
Sympathetic- emergency; fight or flight

54. Both serve the same organ
Each release different neurotransmitters
Parasympathetic= cholinergic fibers
Sympathetic= adrenergic fibers

56. Pre-ganglion neuron secretes acetylcholine
Parasympathetic
Pre-ganglion neuron secretes acetylcholine
Post-ganglion neuron secretes acetylcholine

57. Pre- ganglion neuron secretes acetylcholine
Sympathetic
Pre- ganglion neuron secretes acetylcholine
Post- ganglion neuron secretes epinepherine

58. Continued homeostasis
Parasympathetic
Rest and digest
Continued homeostasis

59. Sympathetic Increased: heart rate, blood pressure and glucose
Dilation of: bronchioles and blood vessels
Close down digestive system
Activate adrenal glands

60. Developmental problems
Nervous system develops in the 1st month of pregnancy
Viruses, drugs, alcohol, smoking can affect embryo

61. Birth Defects
Cerebral Palsy
Hydrocephalus (fluid on brain)
Anencephaly (small brain, missing skull parts)
Spina bifida
Microcephaly (Zika virus)

62. Continued development
Last to form = Hypothalamus
Myelination continues through childhood
Brain reaches maximum weight in the young adult (20s)
New neural pathways can always be formed (learning)

63. Aging Problems Sympathetic system becomes inefficient in the elderly
Arteriosclerosis and High Blood Pressure can cause decreased brain oxygen = senility
< 5% senility at age 65
Boxers and chronic alcoholics show shrunken brains = senility

64. Reversible Senility
Drug side effects, low blood pressure, depression, dehydration, and malnutrition can cause types of senility that will improve if the initial problem is corrected