Nervous System

1. Nervous System

3. Nervous System Organs & Divisions of the Nervous System Central Nervous System (CNS) Peripheral Nervous System (PNS) Autonomic Nervous System (ANS)

4. Nervous System Cells of the Nervous System Neurons 3 parts Dendrites (impulses to cell body) Cell body Axon (impulses away from cell body)

5. Nervous System

6. Nervous System Function of Neurons: Sensory- conducts impulses to spinal cord and brain. Afferent Motor – conducts impulses away from brain and spinal cord. Efferent Interneuron – conducts impulses from sensory to motor neurons

7. Nervous System Glia (neuroglia) Support cells, brings cells of nervous tissue together structurally and functionally 3 types : Astrocytes – star shaped cells that anchor blood vessels to neurons.

8. Nervous System Microglia – small cells that move in inflamed brain tissue carrying phagocytes

9. Nervous System Oligodendrocytes – form myelin sheaths on axons in CNS

10. Nervous System Nerves – bundle of peripheral axons Tract – bundle of central axons White matter – tissue composed of myelinated axons Gray matter – tissues composed of cell bodies and unmyelinated fibers

11. Nervous System Nerve coverings – fibrous connective tissue Endoneurium – surrounds individual fibers within a nerve Perineurium – surrounds a group of nerve fibers Epineurium – surrounds entire nerve.

12. Nervous System Reflex arcs – results in a reflex of a muscle or secretion from a gland

13. Nervous System 2- neuron are is simplest 3- neuron is more complex involving interneurons

14. Nervous System Nerve Impulses – wave of electrical disturbance that travels along surface of neuron membrane Mechanism Stimulus triggers opening of Na+ channels in the plasma membrane of the neuron Inward movement of positive ions leaves slight excess of negative ions outside at a stimulated point, marking the beginning of a nerve impulse

15. Nervous System The Synapse – chemical compounds released from axon terminals into synaptic cleft

16. Nervous System Neurotransmitters bind to specific receptor molecules in the membrane of the postsynaptic neuron, opening ion channels and stimulating impulse conduction.

17. Nervous System At the synaptic terminal, an electrical impulse will trigger the migration of vesicles containing neurotransmitters toward the presynaptic membrane. The vesicle membrane will fuse with the presynaptic membrane releasing the neurotransmitters into the synaptic cleft. Until recently, it was thought that a neuron produced and released only one type of neurotransmitter. This was called "Dale's Law." However, there is now evidence that neurons can contain and release more than one kind of neurotransmitter

18. Nervous System Names of Neurotransmitters Acetylcholine Catecholamine norepinephrine (increases cardiac output) dopamine (Effects emotion/moods, pleasure) serotonin (compound that aids in sleep)

19. Nervous System Central Nervous System Divisions of the brain Brainstem Medulla oblongata Pons Midbrain

20. Nervous System Gray matter in brainstem, function as reflex centers: Heartbeat Respirations Blood vessel diameter Sensory tracts conducts impulses to higher parts of the brain Motor tracts from brain’s higher part conduct impulses to spinal cord.

21. Nervous System Diencephalon - thalamus and hypothalamus

22. Nervous System Brain Structure Function Associated Signs and Symptoms Thalamus Processing center of the cerebral cortex. Coordinates and regulates all functional activity of the cortex via the integration of the afferent input to the cortex (except olfaction). Contributes to affectual expression.  Altered level of consciousness. Loss of perception. Thalamic syndrome - spontaneous pain opposite side of body. 

23. Nervous System Hypothalamus Integration center of Autonomic Nervous System (ANS): Regulation of body temperature and endocrine function. Anterior Hypothalamus: parasympathetic activity (maintenance function). Posterior Hypothalamus: sympathetic activity ("Fight" or "Flight", stress response. Behavioral patterns: Physical expression of behavior. Appestat: Feeding center. Pleasure center.   Hormonal imbalances. Malignant hypothermia. Inability to control temperature. Diabetes Insipidus (DI). Inappropriate ADH (SIADH). Diencephalic dysfunction: "neurogenic storms". 

24. Nervous System Internal Capsule  Motor tracts.  Contralateral plegia (Paralysis of the opposite side of the body).  Reticular Activating System (RAS) Responsible for arousal from sleep, wakefulness, attention.  Altered level of consciousness

25. Nervous System Cerebellum – 2nd largest part of the brain Coordination of voluntary movement Balance and equilibrium Some memory for reflex motor acts.

26. Nervous System Cerebellum -

27. Nervous System Cerebrum – Determines Intelligence Personality Interpretation of Sensory Impulses Motor Function Planning and Organization Touch Sensation

28. Nervous System

29. Nervous System Frontal Lobe- associated with reasoning, planning, parts of speech, movement, emotions, and problem solving Parietal Lobe- associated with movement, orientation, recognition, perception of stimuli Occipital Lobe- associated with visual processing Temporal Lobe- associated with perception and recognition of auditory stimuli, memory, and speech

30. Nervous System Spinal Cord -

31. Nervous System The spinal cord is the main pathway for information connecting the brain and peripheral nervous system. The human spinal cord is protected by the bony spinal column shown to the left. The spinal column is made up of bones called vertebrae. Although the spinal column is somewhat flexible, some of the vertebrae in the lower parts of the spinal column become fused.

32. Nervous System Brain & Spinal Cord Coverings

33. Nervous System Dura mater (tough, leathery) Arachnoid mater (web-like) Pia mater (tender tissue)

34. Nervous System Cerebrospinal fluid (CSF) is a clear, colorless liquid that bathes the central nervous system. While the primary function of CSF is to cushion the brain within the skull and serve as a shock absorber for the central nervous system, CSF also circulates nutrients and chemicals filtered from the blood and removes waste products from the brain. Examining the fluid can be useful in diagnosing many diseases of the nervous system, including MS.

35. Nervous System Peripheral Nervous System Cranial Nerves

36. Nervous System Cranial Nerves – Introduction To help memorize each, a mnemonic is often used by students such as . . ."On Old Olympic Towering Tops A Finn And German Viewed Some Hops"

37. Nervous System Spinal Nerves Nerve Chart

38. Nervous System The Autonomic Nervous System Regulates body’s involuntary functions Sympathetic – Stress Parasympathetic- relaxed

39. Nervous System Autonomic Neurotransmitters Acetylcholine – released by pre-gang axons of para and symp systems, and by post-gang axons of parasympathetic system, called cholinergic fibers. Norepinephrine- post-gang neurons of sympathetic system, called adrenergic fibers

40. Nervous System Autonomic system regulates the body’s automatic functions in ways that maintain or quickly restore homeostasis.

41. Nervous System Many visceral effectors are doubly innervated (have fibers from both parasympathetic and sympathetic systems)