2. The Nervous System 6
Lesson 6.1: Overview of the Nervous System Lesson 6.2: Transmission of Nerve Impulses Lesson 6.3: Functional Anatomy of the Central Nervous System Lesson 6.4: Functional Anatomy of the Peripheral Nervous System Lesson 6.5: Injuries and Disorders of the Nervous System

3. Overview of the Nervous System
Chapter 6: The Nervous System
Lesson 6.1
Overview of the Nervous System

4. Do Now
Pick three words and write the definition of each. All words are on page 201.
Central Nervous System
Peripheral Nervous System
Afferent Nerves
Efferent Nerves
Somatic Nervous System
Autonomic Nervous System

5. Today’s Objectives
Differentiate between the central nervous system and peripheral nervous system, and explain the function of each.
Explain the differences between afferent and efferent nerves.
Describe the functions of the somatic and autonomic branches of the nervous system.
Identify the general role of the glial cells.
Describe the anatomical structure of a typical neuron.

6. Nervous System Overview
The nervous system controls voluntary movement by activating skeletal muscle, but also directs the involuntary functions of smooth muscle in internal organs and cardiac muscle.
By automatically controlling the functions of smooth muscle and cardiac muscle, the nervous system ensures that these life functions are able to occur without conscious thought.

7. Nervous System Overview
organization of the nervous system
two major divisions categorized by:
Structural
Functional
the efferent nerves
nervous tissues
neuroglia
neurons

8. Organization of the Nervous System
Two major divisions
Central nervous system (CNS)
Peripheral nervous system (PNS)
Peripheral nervous system divided into subdivisions:
sensory receptors
afferent (sensory) nerves
efferent (motor) nerves

9. Two Major Divisions

10. Major Divisions Central Nervous System (CNS) Peripheral Nervous System
Includes the brain and spinal cord.
The CNS directs the activity of the entire nervous system.
Peripheral Nervous System
Includes spinal nerves that transmit information to and from the spinal cord
Cranial nerves transmit information to and from the brain.
Also includes sensory receptors which respond to stimuli such as pressure, pain, or temperature.

11. Afferent Nerves Efferent Nerves
Nerves that transmit impulses from the sensory receptors in the skin, muscles, and joints to the CNS
Efferent Nerves
Nerves that carry impulses from the CNS out to the muscles and glands.

12. The Efferent Nerves
There are two functional subdivisions of the efferent (motor) nerves
somatic nervous system
Stimulates skeletal muscles causing them to develop tension.
Voluntary control
autonomic nervous system
Controls the cardiac muscle of the heart and the smooth muscles of the internal organs.
Involuntary control
Includes two separate branches
sympathetic
parasympathetic

13. Nervous Tissues 2 Categories of tissues neuroglia neurons
also known as glial cells
support the neurons
protect the neurons
neurons
transmit nerve impulses

14. Neuroglia astrocytes microglia ependymal oligodendrocytes
Within the central nervous system there are 4 types of glial cells.
astrocytes
microglia
ependymal
oligodendrocytes

15. Central Nervous System Glial Cells
Astrocytes
Positioned between neurons and capillaries.
Protect the neurons from any harmful substances in the blood.
Microglia
Absorb and dispose of dead cells and bacteria
Ependymal
Form protective coverings around the spinal cord and central cavities within the brain.
Oligodendrocytes
Wrap around nerve fibers and produce a fatty insulating material called myelin.

16. Neuroglia peripheral nervous system includes 2 forms of glial cells
Schwann cells
Form the fatty myelin sheaths around nerve fibers
satellite cells
Serve as cushioning support cells

17. Neurons
Glial cells provide support and protection for the nervous system, but it is the neurons that transmit information in the form of nerve impulses.
Typical neuron has a long, tail-like projection called an axon.
dendrites
send information to cell body
cell bodies
Includes a nucleus and mitochondria
axons
send information away from cell body

18. Neuron Types by Function
sensory neurons (afferent)
send impulses toward CNS
Impulses from the skin and organs to the spinal cord and brain.
Provides information about the external and internal environments.
motor neurons
send impulses away from CNS
Transmits impulses from the brain and spinal cord to the muscles and glands, directing body actions.
interneurons
bridges between neurons

19. Neuron Structures bipolar unipolar multipolar
one axon and one dendrite
unipolar
one axon
multipolar
one axon and many dendrites

20. Review and Assessment
Match these words with 1–4 below: sympathetic nervous system, myelin, synapse, axon. 1. high alert 2. transmits impulses away from cell body 3. fatty insulating material 4. gap between neurons

21. END

22. Exit Ticket
Which of the following is not a major division of the nervous system?
a. Central Nervous System
b. Peripheral Nervous System
c. Afferent Nervous System

23. 2) T or F: The central nervous system has afferent nerves that carry impulses TOWARDS muscles and glands. 3) When sending nerve impulses, the purpose of the myelin sheaths are to: a. Decrease the speed of the transmission. b. Increase the speed of the transmission. c. Block any messages being sent. d. None of the above.

24. Transmission of Nerve Impulses
Chapter 6: The Nervous System
Lesson 6.2
Transmission of Nerve Impulses

25. Do Now Work on the “Learning the Key Terms” Worksheet
Chapter 6 Lesson 2 begins on page 202, or use the glossary which begins on page 579.
You have 8 minutes to complete the worksheet.
Turn the worksheet into Mr. B when you are finished.

26. Today’s Objectives Lesson 6.2 Transmission of Nerve Impulses
Define action potential and explain how action potentials are generated.
Explain the factors that influence the speed of neural impulse transmission.
Describe how impulses are transmitted across the synapse.
Discuss the roles played by neurotransmitters.
Describe the three types of reflexes and explain how they work.

27. Intro
Neurons have one behavior property in common with muscles: Irritability – the ability to respond to a stimulus.
However, neurons have an aspect of irritability that muscles DO NOT have: converting stimuli into nerve impulses.
Nerve impulse = a tiny electrical charge that transmits information between neurons.

28. Transmission of Nerve Impulses
Action Potentials
When a neuron is inactive, there are potassium ions (K+) inside the cell and sodium (Na+) ions outside the cell membrane.
Inside of the membrane is more negatively charged than the outside (Polarized).
When a stimulus is involved it changes the charge so the inside is more positive (Depolarized)
This change in charge is known as an Action Potential.
Following the discharge of the action potential, it goes back to it original charge (Repolarization)

29. Transmission of Nerve Impulses
Impulse Transmission
3 factors that have a major impact on the speed at which a nerve impulse travels:
Myelin sheath
The presence of a myelin sheath acts as an electrical insulator and causes the action potentials to “jump”.
This increases the speed in which an impulse travels.
Diameter of Axon
The larger the axon, the more ions available to conduct the current.
Example: A large diameter pipe moves more water compared to a small diameter pipe.

30. Transmission of Nerve Impulses
Temperature
Warm temperatures increase ion diffusion rates.
This increases the speed at which impulses will travel.
Cold temperatures decrease diffusion rates.
Example: when you hold an ice cube you have a numbing sensation. The cold area takes longer to send information about touch, pain, pressure, and temperature to your brain.

31. Impulse Transmission Transmission at Synapses Neurotransmitters
Chemical messengers
excitatory effect
Activates muscle fibers
Inhibitory effect
Blocks pain messages

32. Reflexes
Reflexes
Simple, rapid, involuntary, programmed responses to stimuli.
2 Categories of reflexes:
Somatic
Involve the skeletal muscles.
Example: withdrawing your hand quickly from something hot even before you realized that it was hot.
Autonomic Reflexes
Send involuntary stimuli to the cardiac muscle of the heart and the smooth muscle of internal organs.
Stimulates involuntary muscles.

33. Review and Assessment
Fill in the blanks with: reflexes, saltatory conduction, neurotransmitter, or action potential.
1. A(n) _______________ is an all or none response.
Action Potential
Saltatory conduction
2. _______________ occurs only in myelinated axons.
Reflexes
neurotransmitter
3. _______________ are rapid, involuntary responses.
4. The axon terminal has tiny vesicles filled with _______________.

34. END

35. Exit Ticket
Some factors that can influence the speed of a nerve impulse are:
a. body temperature
b. diameter of the axon
c. presence of a myelin sheath
d. all of the above
e. none of the above

36. 2) T or F: An action potential is generated when an electrical charge produced in a nerve or muscle fiber through stimulation. 3) Reflexes are ___: a. complex, slow, and voluntary responses b. complex, fast, and involuntary responses c. simple, rapid, and involuntary responses d. simple, slow, and voluntary responses.

37. 4) Somatic reflects involve which type of muscles and which type of action? a. Skeletal muscle, involuntary b. Skeletal muscle, voluntary c. Cardiac, voluntary d. Cardiac, involuntary

38. Functional Anatomy of the Central Nervous System
Chapter 6: The Nervous System
Lesson 6.3
Functional Anatomy of the Central Nervous System

39. Do Now Work on the “Learning the Key Terms” Worksheet.
Chapter 6 Lesson 3 begins on page 207.
You have 8 minutes to complete the worksheet.
Turn the worksheet in when you are finished.

40. Expectations General Reminder for Expectations:
There is no talking during lecture.
If you are finished with the Do Now, hold it until after we are done with the lecture. Do not give it to me during the lecture.
1 warning for classroom disruptions and then it’s a detention.
No talking during Exit Tickets.

41. Today’s Objectives
Lesson 6.3 Functional Anatomy of the Central Nervous System
Identify the four lobes of the brain and their functions.
Describe the location, structures, and functions of the diencephalon, or interbrain.
Describe the location, structures, and functions of the brain stem.
Explain the role of the cerebellum.
Identify the membranes that comprise the meninges and explain their purposes.
Describe how the capillaries in the brain are different from other capillaries and explain why this is important.
Identify the location and functions of the spinal cord.

42. Intro
The central nervous system includes numerous anatomical structures with specialized functions.
Scientists have been able to identify which structures control or contribute to physiological processes and actions.

43. The Brain
The brain is vitally important for directing the activity of the entire nervous system.
Structurally and functionally complex.
Adult brain weighs between 2.25lbs and 3.25lbs.
Contains roughly 100 billion neurons.
4 Major anatomic regions of the brain:
cerebrum
diencephalon
brain stem
cerebellum
meninges
blood-brain barrier

44. Cerebrum
The left and right cerebral hemispheres are collectively referred to as the cerebrum, which makes up the largest portion of the brain.
cerebral cortex – the outer surface of the cerebrum
Gyrus – the brain surface is not smooth. Each of the curved, raised areas are called gyrus.
Sulcus – each of the grooves between the gryi.
Fissure – deep grooves in the brain.
The longitudinal fissure runs the length of the brain and divides in into left and right hemispheres.
Neural communications to and from the right side of the body are controlled by the left brain, and communications with the left side of the body are controlled by the right brain.

45. Lobes of the Brain
Frontal – located behind the forehead in the most anterior portion of the brain are sectioned off from the rest of the brain by the central sulcus.
Parietal – located posterior to the frontal lobes.
Include the primary somatic sensory cortex.
Occipital – posterior to the parietal lobes are responsible for vision.
Temporal – most inferior lobes.
Involve speech, hearing, vision, memory, and emotion.

46. primary somatic sensory cortex
primary motor cortex
Anterior to the central sulcus.
Sends neural impulses to the skeletal muscles to initiate and control the development of muscle tension and movement of our body parts.
primary somatic sensory cortex
Interprets sensory impulses received from the skin, internal organs, muscles, and joints.

47. Cerebrum

48. Diencephalon Also known as the interbrain.
Located deep inside the brain, enclosed by the cerebral hemispheres.
Includes the following structures:
thalamus
hypothalamus
epithalamus

49. Thalamus
Serves as a relay station for communicating both sensory and motor information between the body and the cerebral cortex.
Regulates body’s states of arousal, including sleep, wakefulness, and high-alert consciousness.
Hypothalamus
Key part of the autonomic nervous system
Regulates metabolism, heart rate, blood pressure, thirst, hunger, energy level, and body temperature.
Also houses the centers for sex, pain, and pleasure.
Epithalamus
Includes the pineal gland
Regulates the sleep-cycle hormones that it secretes.

50. Brain Stem The brain stem is about the size of a thumb.
Includes three structures:
Midbrain
Serves as a relay station for sensory and motor impulses.
Specifically relays information about vision, hearing, motor activity, sleep and wake cycles and temperature regulation.
Pons
Located below midbrain
Regulates breathing
medulla oblongata
Regulates heart rate, blood pressure, and breathing.
Controls reflexes for coughing, sneezing, and vomiting.

51. Cerebellum Found below the occipital lobe
Coordinates body movements, including balance.
Receives input from the eyes, inner ears, and sensory receptors throughout the body.

52. The Brain
Meninges
Protective barriers that surround the brain and spinal cord.
dura mater – outer layer right beneath the skull
arachnoid mater – contains web-like tissue
pia mater – innermost layer that attaches directly to the surface of the brain and spinal cord.

53. Blood-Brain Barrier
Rich network of blood vessels supply the brain with blood.
The brain depends on blood to provide nutrients and carry away waste products.
At any time, 20% - 25% of the body’s blood is circulating in the region of your brain.
Blood-brain barrier protects the brain against surges in concentrations of hormones, ions, and some nutrients.

54. Spinal Cord

55. Spinal Cord
Extends from the brain stem down to the beginning of the lumbar region of the spine.
Serves as a pathway for relaying sensory impulses to the brain and motor impulses from the brain.
The spine is surrounded and protected by the three meninges and cerebrospinal fluid.

56. Review and Assessment
True or False? 1. The gyri divide the brain into 4 regions. 2. The hypothalamus regulates blood pressure. 3. The meninges has 3 layers. 4. The cerebellum coordinates balance. 5. The pons is also called the interbrain.

57. END

58. Exit Ticket
Which of the following is not one of the four lobes of the brain?
a. Frontal
b. Parietal
c. Zygomatic
d. Occipital
e. Temporal

59. 2) The diencephalon is known as the interbrain
2) The diencephalon is known as the interbrain. Which of the following is not one of the major structures of the interbrain? a. Thalamus b. Hypothalamus c. Perithalamus d. Epithalamus

60. 3) T or F: The cerebellum is responsible for coordinating body movements, including balance. 4) The blood-brain barrier protects the brain from: a. hormones b. alcohol c. nicotine

61. 5). Neural communications to and from the right side of the body are controlled by which side of the brain? a. Left b. Right

62. Functional Anatomy of the Peripheral Nervous System
Chapter 6: The Nervous System
Lesson 6.4
Functional Anatomy of the Peripheral Nervous System

63. Do Now Work on the “Learning the Key Terms” Worksheet.
Chapter 6 Lesson 4 begins on page 216.
You have 8 minutes to complete the worksheet.
Turn the worksheet in when you are finished.

64. Today’s Objectives Describe the basic structure of a nerve.
Identify the twelve cranial nerves and the purpose of each.
Explain the organization of the spinal nerves, the dorsal and ventral rami, and the plexuses.
Describe the location, structure, and function of ganglions.
Differentiate between the functions of the sympathetic and parasympathetic nervous systems.

65. Functional Anatomy of the Peripheral Nervous System
The peripheral nervous system transmits information to the CNS and carries instructions from the CNS.
nerve structure
Each nerve consists of a collection of axons and nutrient supplying blood vessels.
Each axon is covered by the endoneurium
Groups of these fibers are bundled into fascicles surrounded by a protective perineurium.
Groups of fascicles and blood vessels are encased in a tough epineurium.

66. Nerve Structure
Fill out the left side of the worksheet with the appropriate terms.

67. Turn to Page 217 and fill out the functions of the cranial nerves.
Twelve pairs of cranial nerves
Send impulses to and from the left and right sides of the brain.
Some of the nerves only contain afferent (sensory) fibers, and some only contain efferent (motor) fibers, and others are mixed.
Turn to Page 217 and fill out the functions of the cranial nerves.

68. Spinal Nerves and Nerve Plexuses
31 pairs of spinal nerves branch out from the left and right sides of the spinal cord.
The spinal nerve cell bodies are located within the gray matter of the spinal cord.
dorsal root and ventral root
Both nerves unite to form the left and right spinal nerves that exit at each spinal level.

69. dorsal ramus and ventral ramus
Each spinal nerve is only about one-half of an inch.
Each nerve branches out into the dorsal and ventral rami.
All of the rami are mixed nerves carrying both afferent and efferent.
Dorsal rami transmit motor impulses to the posterior trunk and relay sensory impulses from the skin of the back.
Ventral rami communicate with the anterior and lateral trunk.
Plexuses
Complex interconnections of nerves.

70. autonomic nervous system
One of two divisions of the peripheral nervous system.
Autonomic nervous system is programmed by the CNS to activate the heart, smooth muscles, and glands.
Within the autonomic system, two nerves connect the CNS to the organs supplied.

71. Autonomic Nervous System
sympathetic nerves
Activate the fight-or-flight action response
Stimulates the adrenal gland to produce adrenaline.
Preganglionic neurons in the sympathetic system secrete acetylcholine to stimulate postganglionic neurons.
Postganglionic neurons release the neurotransmitter norepinephrine.

72. parasympathetic nerves
Controls all of the automatic, day-in and day-out functions of the circulatory, respiratory, and digestive systems.
Sometimes called the resting or digesting action
Produces a calming effect that returns the body to a normal state.

73. Review and Assessment
Match these words with 1–4 below: efferent, ganglion, optic, perineurium. 1. wraps fascicles 2. motor 3. a cranial nerve 4. enlarged junction

74. END

75. EXIT TICKET Which of the following is not part of the nerve structure?
a. Endoneurium
b. Perineurium
c. hyponeurium
d. Epineurium

76. 2) T or F: There are 12 cranial nerves
2) T or F: There are 12 cranial nerves. 3) Sympathetic nerves activate: a. The central nervous system b. the peripheral nervous system c. the flight-or-flight response d. sleep cycle

77. 4) T or F: The parasympathetic nervous system controls the automatic day-in and day-out functions of the circulatory, respiratory, and digestive systems.

78. Injuries and Disorders of the Nervous System
Chapter 6: The Nervous System
Lesson 6.5
Injuries and Disorders of the Nervous System

79. Do Now Work on the “Learning the Key Terms” Worksheet.
Chapter 6 Lesson 5 begins on page 223.
You have 8 minutes to complete the worksheet.
Turn the worksheet in when you are finished.

80. Injuries to the Brain and Spinal Cord
Because of the critical roles played by the central nervous system, injuries and disorders of the CNS can have potentially serious consequences.
The brain and spinal cord are well protected. The are encased, respectively, in the skull and vertebral column.
traumatic brain injury
cerebral palsy
spinal cord injury

82. Traumatic Brain Injury
violent impact to head
mild
moderate
severe

83. Cerebral Palsy damage to brain motor function impairment before birth
during birth
during infancy
motor function impairment

84. Spinal Cord Injuries C1–C3: usually fatal C1–C4: quadriplegia
C5–C7: paralysis of lower extremities
T1–L5: paraplegia
Corepics/Shutterstock.com

85. Common Diseases and Disorders of the CNS
meningitis
multiple sclerosis
epilepsy
Parkinson’s disease
dementia and Alzheimer’s disease

86. Review and Assessment
Match these words with 1–4 below: quadriplegia, multiple sclerosis, dementia, cerebral palsy. 1. inflammation destroys myelin sheath 2. loss of memory and thinking 3. loss of function below the neck 4. may begin before birth