1. Nervous System What are the functions of the nervous system?
1) Detect stimuli (environment & self)
2) Conduct impulses, integrate, evaluate impulses (stimuli), memory
3) Respond (movements, maintain homeostasis etc.)

2. Nervous System Nerve cells ~ Neurons Maintaining cells ~ Glial cells
What are the Structural/functional units of the Nervous System?
Nerve cells ~ Neurons
Maintaining cells ~ Glial cells
Neuron anatomy:
Neuron cell body
Dendrites
Axons

3. Nervous System What are the different types of Neurons?
Structural types:
Multipolar
Bipolar
Unipolar
Functional types:
Association ~ Interneurons
Afferent ~ Sensory neurons
Efferent ~ Motor neurons

4. Nervous System Astrocytes: control substances entering/leaving CSF
What are the types of glial cells and what tasks do they accomplish?
Astrocytes: control substances entering/leaving CSF
Associated with blood-brain barrier which is formed by endothelial cells of blood vessels.

5. Nervous System Ependymal cells:
What are the types of glial cells and what tasks do they accomplish?
Ependymal cells:
Line the ventricles (cavities) of CNS, create cerebral spinal fluid and aid in its circulation.

6. Nervous System Microglia:
What are the types of glial cells and what tasks do they accomplish?
Microglia:
Small specialized macrophages that attract to areas of damage in the CNS and phagocytize debris

7. Nervous System Oligodendrocytes:
What are the types of glial cells and what tasks do they accomplish?
Oligodendrocytes:
Cells in the CNS that have multiple extensions that wrap around multiple axons forming myelin sheaths.

8. Nervous System
What are the types of glial cells and what tasks do they accomplish?
Schwann cells: Cells in the PNS that wrap around single axons forming myelin sheaths.
The gaps in between Schwann cells are called Nodes of Ranvier

9. Nervous System
The Brain: development…
Our central nervous system has humble origins early in our development (by 3rd wk.)
A plate (neural plate) of cells develop crests (neural crests) that rise and eventually meet and fuse leaving the hollow dorsal nerve cord & and ventricles of our CNS

10. Nervous System The Brain: development…
Swellings around 3 continuous chambers are precursors to forebrain (prosencephalon), midbrain (mesencephalon) and hindbrain (rhombencephalon)
Further differentiation results in 5 brain parts:
Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon

11. Nervous System The Brain: development…
Telencephalon Diencephalon Mesencephalon Metencephalon Myelencephalon

12. Nervous System Brain Spinal cord Nerves Sense organs
How is the Nervous System organized?
Brain
Spinal cord
Nerves
Sense organs
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
43 (12 cranial & 31 spinal nerves)

13. Nervous System The basic components of the CNS include the: Cerebrum
The Brain: the big picture…
The basic components of the CNS include the:
Cerebrum
Diencephalon
Cerebellum
Brain stem
Spinal cord

14. Nervous System The brain and spinal cord are protected by meninges
The Brain: from the outside in…
The brain and spinal cord are protected by meninges
3 layers: Dura mater ~ outermost, tough, continuous with periosteum
Arachn oid mater ~ middle layer, spider-web appearance
Pia mater ~ innermost layer, not visible to naked eye

15. Nervous System
The Brain: from the outside in…
ml of CSF circulates throughout the ventricles, down the central canal of the spinal cord and throughout the subarachnoid space.
CSF is reabsorbed back into blood primarily at the venous sinuses found within the dura mater.

16. Nervous System
The Brain: from the outside in…
Ventricles are comprised of 4 major cavities: 1&2 ~ Right and Left Lateral ventricles
3rd ventricle space within thalamus
4th ventricle between cerebellum and brainstem
channel connecting 3rd and 4th cerebral (mesencephalon) aqueduct and if blocked can result in hydrocephaly

17. Nervous System
The Brainstem: Medulla oblongata
Most inferior portion, functions as a conduction pathway (descending motor neuron pathways decussate here) Contralateral/Ipsilateral
Reflex centers for:
regulating heart rate
blood vessel diameter
coughing, sneezing
breathing
swallowing

18. Nervous System Superior to Medulla oblongata.
The Brainstem: Pons
Superior to Medulla oblongata.
Contains more ascending and descending pathways.
Relays information from cerebrum to cerebellum.
Also includes sleep and respiratory centers.

19. Nervous System Small section superior to the pons.
The Brainstem: Midbrain
Small section superior to the pons.
Part of the auditory pathways and visual reflexes
Also involved in regulating muscle tone/activity and coordination

20. Nervous System “Gateway to cerebral cortex”
The Diencephalon: Thalamus
“Gateway to cerebral cortex”
Most sensory stimuli project to the thalamus, which in turn projects to the cerebrum.
Thalamus also influences moods and activities associated with strong emotion.
(Two concepts: Sensory integration and Mood)

21. Nervous System
The Diencephalon: Hypothalamus
Major control center of autonomic nervous system and endocrine system.
Centers associated with:
* Food/H2O intake * Thermoregulation * Cardiovascular regulation * Hormone secretion * Sleep/waking * Emotional behavior

22. Nervous System
The Brain: Cerebrum (bumps and grooves)
The sulcus dividing frontal and parietal lobes is Central Sulcus.
Ridges on either side are Pre & Post gyri
Pre CS ~ motor cortex
Post CS ~ somatic sensory cortex
Motor
Sensory

23. Nervous System Responsible for balance, muscle tone and coordination
The Brain: Cerebellum
Responsible for balance, muscle tone and coordination
Fine motor coordination due to comparator function… compares intended movements with actual movements
Can also “learn” complex movements

24. Nervous System
Does the brain have any peripheral nerves?

25. Nervous System
Does the brain have any peripheral nerves?

26. Nervous System
Does the brain have any peripheral nerves?

27. Nervous System
Does the brain have any peripheral nerves?

28. Nervous System
Does the brain have any peripheral nerves?

29. Nervous System
Does the brain have any peripheral nerves?

30. Nervous System
Does the brain have any peripheral nerves?

31. Nervous System
Does the brain have any peripheral nerves?

32. Nervous System
Does the brain have any peripheral nerves?

33. Nervous System
Does the brain have any peripheral nerves?

34. Nervous System
Does the brain have any peripheral nerves?

35. Nervous System
Does the brain have any peripheral nerves?

36. Nervous System Why is the tongue innervated the way it is?
Depends on ontogenetic & phylogenetic history
Anterior = 1st arch = V
Taste buds = 1st 2nd arch = VII (for fish)
Posterior buds = 3rd arch = IX
Muscles are myotomal = XII

37. Nervous System Spinal cord is link between brain and PNS
What is the anatomy of the spinal cord?
Spinal cord is link between brain and PNS
Spinal cord ends ~ L2 vertebra but trailing nerves form Cauda equina
Enlargements for regions innervating limbs (Cervical and Lumbar)
Regions of convergence/divergence called plexuses

38. Nervous System How are the layers of the meninges arranged?
The dura mater extends down the vertebral foramen.
There is a subdural space that is largely a “potential space”
The arachnoid and pia maters are arranged similarly as in the cranium.

39. Nervous System
How does spinal cord form denote function?
Spinal cord contains white and gray matter (Remember the significance of each?)
gangli
Spinal cord w/ distinct anterior and posterior formations, including “horns” of gray matter. Posterior horn contains neuron cell bodies that synapse with afferent neurons. Anterior horn contains neuron cell bodies that send efferent axon Lateral horns ~ autonomic neuron cell bodies

40. Nervous System Crossed extensor (withdrawal 3) reflex: 1) 2) 3)
What are the various spinal reflexes and how do they work?
Crossed extensor (withdrawal 3) reflex: 1) 2) 3)

41. Nervous System
What is the association between cutaneous sensation and spinal nerves?
Spinal nerves innervate specific regions of the body and are mapped out on a Dermatomal map
Predict the possible site of nerve damage for a patient who suffered whiplash and developed anesthesia in the left arm, forearm and hand!