1 Diagram of the Nervous System 2

1

Diagram of the Nervous System 2

Neurons 3

Axons Thread-like extensions from the cell body l Tube-like fibers that carry impulses away from the soma to the dendrites l Myelin coating l 4

Multiple Sclerosis MS destroys myelin sheaths of axons l This can cause erratic and uncoordinated behavior l 5

6

Dendrites Short, thin fibers that stick out from the cell body l Dendrites receive impulses or messages from other neurons and send them to the cell body l 7

Characteristics of Neurons l They cannot replace themselves l Damage is permanent l Threshold of excitation 8

The Neuron Connection Synapse junction l Neurotransmitters l Open chemical “locks” l Inhibition l 9

How a Neuron Fires 10

Neurotransmitters l l l Acetycholine (memory, movement) Norepinephrine (memory, learning) Serotonin (sleep, appetite) Endorphins (inhibits pain) Dopamine (learning, emotions, movement) 11

Types of Neurons l Ascending vs. descending tracts l Afferent/Sensory neurons l Efferent/Motor neurons l Interneurons/Connecting neurons 12

Voluntary vs. Involuntary Somatic nervous system (voluntary activities) l Autonomic nervous system (involuntary activities) l 13

Divisions of the Autonomic Nervous System Sympathetic nervous system l 1. Fight or flight l 2. Speeds up heart rate/O 2 supply and blood pressure l 3. It constricts some arteries, relaxes others l 14

Parasympathetic Nervous System Works to conserve energy l Helps us recover from strenuous activity l Reduces heart rate and blood pressure l Returns us to a normal resting state l 15

The Brain 16

Divisions of the Brain Hindbrain, located at the rear base of the skull l Contains the cerebellum, the medulla, the pons l 17

The Midbrain Located just above the pons l Function: relays sensory information l Brain stem and reticular activating system l 18

The Forebrain The hindbrain and forebrain compose the brain’s central core l Thalamus (information relay) l Hypothalamus (motivation, emotion) l Higher-thinking processes l 19

Higher-Thinking Processes Cerebral cortex l Cerebrum l 20

The Limbic System l Found in the core of the forebrain l It has a number of different parts: l 1. Thalamus l 2. Hypothalamus l 3. Amygdala l 4. Hippocampus 21

Hemispheres of the Brain The cerebrum has two hemispheres l The corpus callosum l 22

Two Hemispheres 23

Righthanded vs. Lefthanded Handedness—a preference for using one hand l Not an absolute l 90% of people in the U. S. are righthanded l Theories: environmental vs. genetic l 24

Problems Associated With Being a Lefty l Autism and dyslexia l Schizophrenia l Mental retardation l Alcoholism l Life expectancy 25

Lobes of the Brain 26

Lobes and Their Functions l Frontal: planning of movements, working memory l Temporal: hearing, advanced visual processing, memory l Occipital: vision l Parietal: body sensations l Primary motor cortex: fine motor control 27

Split-Brain Surgery Pioneered by Roger Wolcott Sperry 1913 – 1994 l Used to correct epileptic seizures l 28

Side Effects 29

The Spinal Cord l l l Dura matter Arachnoid Pia matter Cerebrospinal fluid Gray vs white matter 30

Looking Inside the Brain 31

Techniques Used to Look Inside the Brain l Electrical recordings l Lesioning l Electrical stimulation l Brain imaging 32

Electrical Recordings Electroencephalograph (EEG) Hans Berger Brainwave patterns 33

Lesioning Brain tumors, strokes, head injuries all cause brain damage l H. Gardner, 1975 l Limitations/ experiments with animals l 34

Electrical Stimulation of the Brain l ESB involves sending a weak electrical current into a brain structure in order to stimulate it l The current mimics brain wave voltage l Most ESB research is done on animals 35

Brain Imaging Techniques l CT (computerized tomography) scans l PET (positron emission tomography) scans l MRI (magnetic resonance imaging) scans 36

The CT Scan Computerized tomography (CT) scan: a computer-enhanced xray of brain structure l Assembling the images l CT/least expensive procedure l 37

Image From a CT Scan 38

PET Scans Positron emission tomography (PET) scan l Radioactive chemicals are used as markers l Provides a colorcoded map of the brain l 39

MRI Scans Magnetic resonance imaging (MRI) scan uses magnetic fields, radio waves, and computerized enhancement l Much more detailed than a CT scan l 40

The Endocrine System 41

The Pituitary Gland Master gland of the body l It contains 3 lobes l The pituitary regulates metabolism by stimulating other glands l 42

Anterior Lobe/Pituitary Gland l l l Somatotrophic hormones Midget Dwarf Giant Acromegaly 43

Justin 44

Other Pituitary Hormones l TSH (thyroid stimulating hormone) l ACTH (adrenocorticotropic hormone) l Gonadotrophic hormone 45

Posterior Lobe Hormones l ADH (anti-diuretic hormone) l Oxytocin 46

The Thyroid Gland Largest gland in the endocrine system trachea and larynx l Located at the junction of the trachea and larynx l Produces thyroxine l 47

Thyroid Disorders l Cretinism l Myxedema l Goiter 48

The Parathyroids The four smallest glands in the endocrine system l They regulate the body’s calcium and phosphorus balances l Tetany l 49

The Thymus Gland l Located behind the breastbone l Its function is not clearly understood l Immune system 50

The Adrenal Gland Located on top of each kidney l Composed of the adrenal cortex and the adrenal medulla l Steriods, cortisone, aldosterone l 51

The Adrenal Medulla Depends on the hypothalamus and the autonomic nervous system for regulation l Epinephrine/ adrenaline l Noradrenalin l 52

The Pancreas Produces insulin and glucogen to control sugar metabolism l Diabetes l 53

Ovaries and Testes in males, ovaries in females l Testosterone l Estrogen and progesterone l 54

Brain Injuries 55

Brain Trauma A physical accident where the head receives a severe blow. l Auto accidents, sports injuries l 56

Types of Head Trauma l Concussion l Contusion l Laceration 57

Concussion Temporary loss of consciousness l Causes no permanent damage to skull or brain tissue l Flaccid paralysis l Symptoms l 58

Concussion 59

Contusions l Actual bruising of neural tissue l May cause a coma l Loss of speech, convulsions, disorientation, delusions 60

Lacerations The most serious of brain injuries l A foreign object such as a bullet enters the skull l Brain tissue is destroyed l 61

James Brady Reagan’s press secretary l Shot March 30, 1981 l Wound to the head l Brady Bill l 62

Cerebral Laceration l The case of Phineas Gage 63

Vascular Accidents l Injuries to brain tissue resulting from blockage or breaking of cranial blood vessels l Cerebral thrombosis/stroke l Strokes are the most common CVAs l Effects 64

Cerebral Hemorrhages l Blood vessels in the brain rupture (aneurysm) l Blood spills directly onto the brain tissue l Coma, convulsions 65

Brain Injuries Resulting from Surgery Techniques for neurosurgery l Transorbital lobotomy l Early lobotomy procedures l Closed standard lobotomy l 66

New Neurosurgery Techniques A thin wire with a tiny magnet on its tip is inserted through the femoral artery into the brain l Helmet-shaped overhead magnet l Endovascular surgery l 67

Brain Infections l Parkinson’s disease l Meningitis l Encephalitis 68

Parkinson’s Disease Degenerative CNS disorder l Rigidity, tremors, gait difficulties l Onset l Gender l 69

Two Types of Parkinson’s Disease Idiopathic PD (primary) l Secondary PD (trauma, cerebrovascular accidents, tumor, drug-induced) l Stages l Causes l 70

Meningitis l An infection of the cerebrospinal fluid and the lining of the brain l It spreads very rapidly, and can cause brain damage and kill in less than 24 hours l Rifampin 71

Symptoms of Meningitis In adults: vomiting, headaches, drowsiness, seizures, high fever, joint pain, stiff neck l In children: arching back and neck, blank stare, refusal to eat, cold hands and feet, vomiting l Diagnosis/spinal tap l 72

Encephalitis l Inflammation of the brain by a virus l Herpes simplex virus (HSV) l Transmission l Milder forms of encephalitis 73

Symptoms of Encephalitis Fever, headache, poor appetite, loss of energy l Severe symptoms also include nausea, vomiting, stiff neck, pupils of different sizes, personality changes, seizures, problems with speech and hearing, double vision, memory loss, and coma. l 74

Preventing Encephalitis l Proper childhood immunizations l Avoiding insect bites l Eliminate standing water around the house 75

Paresis Syphilis of the brain Slide # 76

Causes of Paresis 77

Spirochete 78

The Stages of Syphilis 79

Diagnosis Chancre (A small sore that appears on the lips or sex organs; disappears without treatment l Causes rashes, skin infections, flu-like symptoms, hair loss l Diagnosis of cerebrospinal fluid l 80

Symptoms of Paresis l Pupil of eye does not respond to light l Tremors of fingers, tongue, eyes l Loss of motor control l Shuffling gait l Personality changes 81

Nature vs. Nurture l Heredity: the genetic transmission of characteristics from parents to offspring (nature) l Nurture (environment and learning) l Sir Francis Galton l John Watson 82

Genes and Behavior The basic units of heredity are the genes l Genes are inherited l 83

Twin Studies Identical twins develop from a single fertilized egg (monozygotic) and share the same genes l Twins reared in different environments l 84

Fraternal Twins Develop from two fertilized eggs (dizygotic) l Their genes are no more similar than those of siblings l Twins grow up in same environment l 85

University of Minnesota Experiment Identical twins separated at birth and reared in different environments l From phobias to hobbies l Heredity may contribute more than we ever believed l 86

Hal and Jerry 87