2.  The nervous system is the body’s control and communication center.  It serves to organize incoming data into useful information that can be used for internal functions and, by interpreting external dangers and initiating movement, physical activities necessary for survival

3.  Neuron: is designed to transmit various levels of information from one cell to another.  There are three main types of neuron: › Sensory neurons : Transmit impulses back toward the brain and spinal cord › Motor neurons : Carry impulses away from the brain and spinal cord to the muscles and glands of the body › Associative neurons : Carry impulses from sensory neurons to motor neurons

4.  Parts of neurons: › Dendrites: receive information from another cell and transmit the message to the cell body. › Axon: conducts messages away from the cell body.

5.  Multipolar neurons : neurons with many dendrites and one axon. EX: brain and spinal cord  Bipolar neurons : neurons with only one dendrite and one axon. EX: found only in the inner ear, the olfactory area of the nose, and the retina of the eye  Unipolar neuron : Most sensory neurons are unipolar meaning that they have only one extension

6.  The axon is covered by an insulating material called the neurilemma, also known as the myelin sheath.  It speeds up the electrical signal and prevents it from interacting with other signals.  Nodes of Ranvier : refers to the gaps in the myelin sheath. › These gaps allow ions to flow freely from extracellular fluid to the axons.

7.  These cells do not transmit impulses like the neurons, but instead insulate, support, and protect the neurons. › Astrocyte – Serve as part of the blood brain barrier, which helps to prevent certain substances from entering the brain. › Oligodendroglia – Provide support by forming rigid connections between neurons, also produce myelin for insulation. › Microglial – Protect the neurons through phagocytosis(destroying foreign materials)

9.  Nerve cells generate electrical impulses through a process called membrane excitability  The membrane that separates the cytoplasm on the inside of the cell from the extracellular fluids on the outside of the cell separates two areas of different chemical composition.

10.  Synapse: is an area between the terminal branches of an axon and the ends of a branched dendrite

11.  Reflex: an involuntary reaction to an external response is called a reflex.  The reflex arc has the following components: › A sensory receptor on the skin › An afferent neuron(Sensory) › Associated neurons within the spinal cord › An efferent neuron (motor) › An effector organ Ex: Pg. 173

12.  The nervous system of the human body is divided into two systems:  Central nervous system: composed of the brain and spinal cord.  Peripheral nervous system: composed of the nerves that link the various of the body to the CNS. Includes the cranial nerves.

13.  The primary functions of the nervous system are: › Sensory: detects alterations of internal and external stimuli › Integrative: sensory information is analyzed and appropriate behaviors are selected in response › Motor: the appropriate behaviors are implemented

14.  The PNS can be divided into the somatic nervous system and the autonomic nervous system.  The SNS connects the CNS to skin and skeletal muscles via the cranial and spinal nerves, initiating voluntary responses.  The ANS connects the CNS to visceral organs via the cranial and spinal nerves, initiating involuntary responses.  A sympathetic response prepares the body to deal with emergencies through the expenditure of energy  Parasympathetic response restores homeostatic balance and conserves energy.

16.  Approximately 100 billion neurons that communicate with each other through electrochemical pulses.  These complex interactions are ultimately responsible for all human physical and mental function  Neurons are the same as other body cells except they are specialized to gather and evaluate information from the internal and external environment, and then coordinate a response to that information.

17.  Meninges: Three layers of protective tissue; cover the brain and spinal cord  Dura mater : outermost layer; composed of tough fibrous connective tissue  Arachnoid mater : thin weblike membrane lacking blood vessels  Pia mater : it contains blood vessels and nerves for the nourishment of the underlying neural tissue.

18.  Epidural space : a space between bone and dura.  Subarachnoid space : The space created between the arachnoid mater and the pia mater; contains CSF

20.  Is a layer of neurons on the surface of the brain that is approximately 2-4mm thick.  These neurons are specialized functions, are distributed across layers in the cortex.

21.  Represents that largest portion of the human brain  Divided into separate halves, or hemispheres, by a prominent central groove called longitudinal fissure.  The transverse fissure separates the cerebrum from the cerebellum.  Left Hemisphere generally handles speech functions, whereas the Right Hemisphere deals with nonverbal, intuitive behaviors.  90% of the population the left hemisphere is the dominate hemisphere because it controls verbal, computational and analytical skills.

22.  The two hemispheres are connected by a thick bundle of commissural nerve fibers referred to as the corpus callosum and anterior and posterior commissures.  These structures allow for communication between the brain halves. Refer to Pg. 178

24.  Ventricles: A series of interconnected canal and cavities within the brain.  The first two ventricles are referred to as the lateral ventricles(right and left)  The large ventricles, which are located in each cerebral hemisphere, connect to the smaller third ventricle, located between the halves of the thalamus, by way of interventricular foramen

25.  The third ventricle connects to the even smaller fourth ventricle, located by way of cerebral aqueduct.  The fourth ventricle is continuous with the central canal of the spinal cord.  The ventricles are filled with a clear, colorless fluid containing small amounts of protein, glucose, lactic acid, urea, and potassium, as well as a relatively large amount of sodium chloride.  The fluid, known as CSF, helps to support and cushion the brain and spinal cord, and stabilizes the ionic concentration of the CNS.  It also acts to filter the waste products of metabolism and other substances that diffuse into the brain from blood.

27.  Basal ganglia: collection of nuclei embedded deep within the white matter of the cerebral hemispheres.  They act with the cerebellum to modify movement from moment to moment.

28.  The second largest structure of the brain and is located posterior to the medulla oblongata and inferior to the cerebrum’s occipital lobe.  Separated from the cerebrum by the transverse fissure.  Acts to coordinate skeletal muscle movement by comprising input from the motor cortex of the frontal lobe with proprioceptive feedback from the extremities, and correcting any perceived problems.

29.  Located between the midbrain and the cerebrum.  Surrounds the third ventricle  Primary structures include: › Thalamus › Hypothalamus › Posterior pituitary gland › Pineal gland

30.  Thalamus: acts as a relay station to the cerebral cortex for all sensory data from the cerebellum, brainstem, spinal cord, and other parts of the cerebrum  Hypothalamus: collection of nuclei located just inferior to the thalamus. It regulates homeostasis of the body through coordination of activities of the ANS. Serves as a link between the endocrine system and the nervous system.

31.  Section of the brainstem located between the diencephalon and the pons.

32.  Connects the diencephalon to the spinal cord and consist of the following: › Medulla Oblongata :  connect the brain with the spinal cord.  Five of the 12 cranial nerve nuclei  Responsible for breathing rhythm, heart rate, and blood pressure › Pons :  Connects the brain with the spinal cord and other brain parts.  Four of the 12 cranial nerves  Works with the medulla for regulation of breathing › Midbrain :  Inferior to the thalamus  Contains center for visual reflexes( movement of the head and eyes)

33.  Column of nervous tissue that begins at the level of the foramen magnum and terminates at the level of the first and second lumbar disks.  Protected by the same three meningeal coverings as the brain(dura, arachnoid, and pia mater)  Function is to conduct impulses and serve as a spinal reflex center  At the level of the first lumbar vertebra, a collection of spinal roots descends from the inferior spinal cord, resembling the hairs of a horse’s tail. These nerves are known collectively as the cauda equina.

34.  There are 12 pairs of cranial nerves  Originate in the brainstem with the exception of the 1 st and 2 nd  Roman numerals that indicate the order in which they arise from the brainstem(from the front to the back)

35.  Olfactory (I) - (instrumental in the sense of smell)  Optic (II) - (transmits visual information from the retina to the brain)  Ocularmotor (III) - (controls most of the eye's movement, constriction of the pupil, and maintains an open eyelid)  Trochlear (IV) - (“somatic efferent” that innervates a single muscle: the superior oblique muscle of the eye)  Trigeminal (V) - (responsible for sensation in the face)Pg. 186  Abducens (VI) - (“somatic efferent” nerve that controls the movement of a single muscle, the lateral rectus muscle of the eye)

36.  Facial (VII) - muscles of facial expression, conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity  Vestibulocochlear (VIII) – sound and equilibrium (balance) information from the inner ear to the brain  Glossopharyngeal (IX) – visceral sensory ears, pharynx, back one thirds of tongue  Vagus(X) - innervates the viscera, conveys sensory information about the state of the body's organs  Accessory (XI) – control the sternocleidomastoid and trapezius muscles of the neck  Hypoglossal (XII) - innervates the muscles of the tongue

38.  The spinal cord is made up of continuous nerve tracts and cell columns that can be divided into segments.  31 spinal nerve roots: › 8 cervical › 12 thoracic › 5 lumbar › 5 sacral › 1 coccygeal