Human Nervous System Central Nervous System (CNS) -Brain and spinal cord - interneurones Peripheral Nervous system (PNS) -Everything else (cranial and spinal nerves) -Sensory and motor neurons Somatic Nervous System Autonomic Nervous System - Voluntary- Involuntary - Input from sense organs- Input from internal receptors - Output to skeletal muscles- Output to smooth muscles and glands Sympathetic Motor System Parasympathetic Motor System -`Fight or Flight` response - Relaxing responses - Neurotransmitter: Noradrenaline - Neurotransmitter: Acetylcholine - `Adrenergic System` - `Cholinergic System`

Human Nervous System

Parts of Nervous System: I- Central Nervous system * Brain * Spinal Cord II- Peripheral Nervous System: * Cranial Nerves * Spinal Nerves

Human Nervous System Parts of Nervous System: I- Central Nervous system * Brain * Spinal Cord

Human Nervous System Parts of Nervous System: II- Peripheral Nervous System: * Cranial Nerves * Spinal Nerves

Human Nervous System Parts of Nervous System: II- Peripheral Nervous System: * Cranial Nerves * Spinal Nerves

Human Nervous System I- Central Nervous system Brain Is the primary center for regulation and coordination of body activities. Each portion of the Brain controls different aspects of body function. The Brain is organized so that the left side of the Brain controls the right side of the body and the right side of the Brain controls the left side of the body

Human Nervous System Parts of the Brain 1.Forebrain 2.Midbrain 3.Hindbrain

Human Nervous System Spinal cord Spinal cord carries all the nerves that affect the limbs and lower portion of the body. It is the pathway for impulses going to and from the Brain.

Human Nervous System Cerebrospinal Fluid (CSF) CSF flows throughout the Brain and the spinal cord Its primary function is to cushion these organs from shock and injury.

Human Nervous System Parts of Nervous System: II- Peripheral Nervous System: * Cranial Nerves * Spinal Nerves The cranial nerves are arranged in 12 pairs, so the two nerves on a pair are identical in function and structure. These nerves serve both sensory and motor functions.

Human Nervous System The 12 Cranial Nerves The cranial nerves are generally named for the area or function they serve and are identified with Roman numerals. 1. I - Olfactory 2. II - Optic 3. III - Oculomotor 4. IV - Trochlear 5. V - Trigeminal 6. VI - Abducens 7. VII - Facial 8. VIII - Auditory 9. IX - Glossopharyngeal 10. X - Vagus 11. XI - Accessory 12. XII - Hypoglassal

Human Nervous System

II- Peripheral Nervous System: * Cranial Nerves * Spinal Nerves 1.Cervical nerves 2.Thoracic nerves 3.Lumbar nerves 4.Sacral nerves

Human Nervous System Structure of the Nervous system The basic cells of the nervous system are the Neurons They are composed of a cell body and neural process (nerve fibers) Types of nerve cells 1.Sensory neurons 2.Motor neurons

Human Nervous System Types of nerve cells 1.Sensory neuron: * Afferent Neuron– Moving away from a central organ or point. * Relays messages from receptors to the Brain or Spinal cord.

Human Nervous System Types of nerve cells 2.Motor neuron: * Efferent Neuron– Moving towards a central organ or point. * Relays messages from the Brain or Spinal cord to the muscles and organs.

Human Nervous System Interneuron (relay neurone): * Relays messages from sensory neurone to motor neurone * Make up the Brain and Spinal cord

Human Nervous System Synapses Is the space between two neurons or between a neuron and a receptor organ. Neurotransmitter Is a chemical substance that makes it possible for the impulse to jump across the synapse from one neuron to another.

Human Nervous System Schwann cells Most neurons have many companion cells called Schwann cells, which wrap their cell membrane around the axon many times in a spiral to form a thick insulating lipid layer called the Myelin sheath.

Human Nervous System Myelin sheath - Is the white protective covering of some nerves.

Human Nervous System Myelin sheath * If the nerve is covered with myelin it is referred to as the white matter. * If the nerve is NOT covered with protective myelin sheath is called gray matter which makes up the gray matter of the Brain and spinal cord.

Human Nervous System Central Nervous System (CNS) -Brain and spinal cord - interneurones Peripheral Nervous system (PNS) -Everything else (cranial and spinal nerves) -Sensory and motor neurons Somatic Nervous System Autonomic Nervous System - Voluntary- Involuntary - Input from sense organs- Input from internal receptors - Output to skeletal muscles- Output to smooth muscles and glands Sympathetic Motor System Parasympathetic Motor System -`Fight or Flight` response - Rest and digest responses - Neurotransmitter: Noradrenaline - Neurotransmitter: Acetylcholine - `Adrenergic System` - `Cholinergic System`

Human Nervous System - Most body organs are innervated by two separate sets of motor neurons; one from the sympathetic system one from the parasympathetic system - These neurones have opposite (antagonistic) effects.

Human Nervous System The Autonomic Nervous System Parasympathetic StimulationSympathetic StimulationStructure Pupil constrictionPupil dilationIris (eye muscle) Saliva production increasedSaliva production reducedSalivary Glands Mucus production increasedMucus production reducedOral/Nasal Mucosa Heart rate and force decreasedHeart rate and force increasedHeart Bronchial muscle contractedBronchial muscle relaxedLung Gastric juice secreted; motility increasedPeristalsis reducedStomach Digestion increasedMotility reducedSmall Intestine Secretions and motility increasedMotility reducedLarge Intestine Increased conversion of glycogen to glucose Liver Increased urine secretionDecreased urine secretionKidney Norepinephrine and epinephrine secreted Adrenal medulla Wall contracted Sphincter relaxed Wall relaxed Sphincter closed Bladder

Human Nervous System It should be noted that the autonomic nervous system is always working. It is NOT ONLY active during "fight or flight" or "rest and digest" situations. Rather, the autonomic nervous system acts to maintain normal internal functions and works with the somatic nervous system.