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Neurons Chapter 3.

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1 Neurons Chapter 3

2 The part of the neuron that takes information AWAY from the cell body.
Axon The part of the neuron that takes information AWAY from the cell body.

3 Also called the soma; the part of the cell that contains the nucleus.
Cell Body Also called the soma; the part of the cell that contains the nucleus.

4 Part of the neuron that contains chromosomes (genetic material)
Nucleus Part of the neuron that contains chromosomes (genetic material)

5 Dendrites Extensions from the neuron cell body that take information TO the cell body.

6 Myelin Fatty substance that surrounds some axons. Speeds up conduction velocity of action potentials.

7 Gaps in the myelination of axons.
Node of Ranvier Gaps in the myelination of axons.

8 The end of the axon containing vesicles with neurotransmitters.
Synaptic Terminal The end of the axon containing vesicles with neurotransmitters.


10 The Nervous System

11 Nervous System System of nerves involved in thought processes, heartbeat, visual-motor coordination, etc… Central and Peripheral systems

12 Central Nervous System
Consists of the brain and spinal cord

13 Spinal Cord A column of nerves within the spine that transmits messages from sensory receptors to the brain and from the brain to muscles and glands throughout the body.

14 Spinal Cord Spinal Reflexes: an unlearned response to a stimulus that may involve only two neurons a) Sensory (afferent) neuron-to cortex b) Motor (efferent) neuron-away S A M E You are *affected* by a situation, you *effect* change on someone else. Blink, swallow,knee-jerk, sexual responses, urinating, etc…

15 Brain Hindbrain(lower part of brain):
Medulla-heart rate, blood pressure, respiration Pons-respiration, attention, sleep, dreaming Cerebellum-muscle coordination and balance

16 Brain Vital in the functions of attention, sleep, and arousal
Reticular Activating System (RAS): Vital in the functions of attention, sleep, and arousal Injury to RAS can cause comatose Filtering (awakened by infant)

17 Brain Forebrain (front most part): 1). Thalamus-center of brain
Relay station for sensory stimulation Relays sensory input from the eyes to the visual areas of the cerebral cortex Functions of sleep and attention

18 Brain Forebrain (front most part):
2). Hypothalamus-beneath thalamus and above pituitary gland Body temperature, motivation, emotion Involved in hunger, thirst, sexual behavior, caring for offspring, aggression

19 Brain Forebrain (front most part):
3). Limbic system-inner edge of cerebrum and in mammals only Memory, emotion, drives of hunger, sex, aggression Amygdala-facilitates aggressive responses

20 Brain Forebrain (front most part):
4). Basil ganglia-between thalamus and cerebrum Control of movements and coordination Dopamine produced-degeneration can cause Parkinson’s disease

21 Brain Forebrain (front most part):
5). Cerebrum-crowning glory of brain Cerebral cortex-the wrinkled and convoluted surface Consists of two hemispheres Corpus Callosum-connects the two hemispheres

22 Peripheral Nervous System
Consists of sensory and motor neurons that transmit messages to and from the central nervous system Without the PNS, our brains would be isolated from the world Somatic and Autonomic NS

23 Somatic Nervous System
Connects the central nervous system with sensory receptors, skeletal muscles, and the surface of the body Ex:raising hand, winking, running, posture, balance

24 Autonomic Nervous System
Regulates the glands and the muscles of internal organs Heartbeat, respiration, digestion, dilation of the pupils of the eyes Can occur automatically Sympathetic & Parasympathetic

25 Autonomic Nervous System
Sympathetic- most active during processes that involve the spending of body energy from stored reserves “Fight-or-Flight”

26 Autonomic Nervous System
Parasympathetic- most active during processes that replenish reserves of energy (eating)

27 Autonomic Nervous System
Sympathetic- -accelerates the heart rate -inhibits digestion Parasympathetic- -decelerates the heart rate -stimulates digestive processes

28 Lobes of the Brain

29 Frontal Lobe Located in front of the central sulcus
Concerned with reasoning, planning, parts of speech, movement (motor cortex), emotions, and problem-solving

30 Parietal Lobe Located behind the central sulcus
Concerned with perception of stimuli related to touch, pressure, temperature, pain

31 Temporal Lobe Located below the lateral fissure
Concerned with perception and recognition of auditory stimuli (hearing) and memory (hippocampus)

32 Occipital Lobe Located at the back of the brain, behind the parietal lobe and temporal lobe Concerned with many aspects of vision


34 Brain Structures

35 Cerebral Cortex Thought Voluntary movement Language Reasoning

36 Cerebellum Movement Balance Posture

37 Brain Stem Breathing Heart Rate Blood Pressure

38 Hypothalamus Body temperature Emotions Hunger Thirst Circadian rhythms

39 Thalamus Sensory processing Movement

40 Limbic System Emotions Memory

41 Hippocampus Learning Memory

42 Basal Ganglia Movement

43 Midbrain Vision Audition Eye movement Body Movement

44 The Brain Techniques to Study the Brain A brain lesion experimentally destroys brain tissue to study animal behaviors after such destruction. OBJECTIVE 11| Describe several techniques for studying the brain. Hubel (1990)

45 Clinical Observation Clinical observations have shed light on a number of brain disorders. Alterations in brain morphology due to neurological and psychiatric diseases are now being catalogued. Tom Landers/ Boston Globe

46 Electroencephalogram (EEG)
An amplified recording of the electrical waves sweeping across the brain’s surface, measured by electrodes placed on the scalp.

47 PET Scan PET (positron emission tomography) Scan is a visual display of brain activity that detects a radioactive form of glucose while the brain performs a given task. Courtesy of National Brookhaven National Laboratories

48 MRI Scan MRI (magnetic resonance imaging) uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of brain tissue. Top images show ventricular enlargement in a schizophrenic patient. Bottom image shows brain regions when a participants lies. Both photos from Daniel Weinberger, M.D., CBDB, NIMH James Salzano/ Salzano Photo Lucy Reading/ Lucy Illustrations

49 Older Brain Structures
The Brainstem is the oldest part of the brain, beginning where the spinal cord swells and enters the skull. It is responsible for automatic survival functions. OBJECTIVE 12| Describe the components of the brainstem and summarize the functions of the brainstem, thalamus and cerebellum.

50 Brain Stem The Medulla [muh-DUL-uh] is the base of the brainstem that controls heartbeat and breathing. Reticular Formation is a nerve network in the brainstem that plays an important role in controlling arousal.

51 Brain Stem The Thalamus [THAL-uh-muss] is the brain’s sensory switchboard, located on top of the brainstem. It directs messages to the sensory areas in the cortex and transmits replies to the cerebellum and medulla.

52 Cerebellum The “little brain” attached to the rear of the brainstem. It helps coordinate voluntary movements and balance.

53 The Limbic System The Limbic System is a doughnut-shaped system of neural structures at the border of the brainstem and cerebrum, associated with emotions such as fear, aggression and drives for food and sex. It includes the hippocampus, amygdala, and hypothalamus. OBJECTIVE 13| Describe the structures and functions of the limbic system, and explain how one of these structures controls the pituitary gland.

54 Amygdala The Amygdala [ah-MIG-dah-la] consists of two almond-shaped neural clusters linked to the emotions of fear and anger.

55 Hypothalamus The Hypothalamus lies below (hypo) the thalamus. It directs several maintenance activities like eating, drinking, body temperature, and control of emotions. It helps govern the endocrine system via the pituitary gland.

56 Reward Center Rats cross an electrified grid for self-stimulation when electrodes are placed in the reward (hypothalamus) center (top picture). When the limbic system is manipulated, a rat will navigate fields or climb up a tree (bottom picture). Sanjiv Talwar, SUNY Downstate

57 The Cerebral Cortex The intricate fabric of interconnected neural cells that covers the cerebral hemispheres. It is the body’s ultimate control and information processing center. OBJECTIVE 14| Define cerebral cortex and explain its importance fro the human brain.

58 Structure of the Cortex
Each brain hemisphere is divided into four lobes that are separated by prominent fissures. These lobes are the frontal lobe (forehead), parietal lobe (top to rear head), occipital lobe (back head) and temporal lobe (side of head). OBJECTIVE 15| Identify the four lobes of the cerebral cortex.


60 Functions of the Cortex
The Motor Cortex is the area at the rear of the frontal lobes that control voluntary movements. The Sensory Cortex (parietal cortex) receives information from skin surface and sense organs. OBJECTIVE 16| Summarize some of the findings on the functions of the motor cortex and the sensory cortex, and discuss the importance of the association areas.

61 Visual Function The functional MRI scan shows the visual cortex is active as the subject looks at faces. Courtesy of V.P. Clark, K. Keill, J. Ma. Maisog, S. Courtney, L.G. Ungerleider, and J.V. Haxby, National Institute of Mental Health

62 Auditory Function The functional MRI scan shows the auditory cortex is active in patients who hallucinate.

63 Association Areas More intelligent animals have increased “uncommitted” or association areas of the cortex.

64 Language Aphasia is an impairment of language, usually caused by left hemisphere damage either to Broca’s area (impaired speaking) or to Wernicke’s area (impaired understanding). OBJECTIVE 17| Describe the five brain areas that would be involved if you read this sentence aloud.


66 Specialization & Integration
Brain activity when hearing, seeing, and speaking words


68 The Brain’s Plasticity
The brain is sculpted by our genes but also by our experiences. Plasticity refers to the brain’s ability to modify itself after some type of injury or illness. OBJECTIVE 18| Discuss brain’s plasticity following injury or illness.

69 Our brain is divided into two hemispheres.
Our Divided Brain Our brain is divided into two hemispheres. The left hemisphere processes reading, writing, speaking, mathematics, and comprehension skills. In the 1960s, it was termed as the dominant brain. OBJECTIVE 19| Describe split-brain research, and explain how it helps us to understand the functions of our left and right hemispheres.

70 Splitting the Brain A procedure in which the two hemispheres of the brain are isolated by cutting the connecting fibers (mainly those of the corpus callosum) between them. Corpus Callosum Courtesy of Terence Williams, University of Iowa Martin M. Rother

71 Split Brain Patients With the corpus callosum severed, objects (apple) presented in the right visual field can be named. Objects (pencil) in the left visual field cannot.

72 Divided Consciousness

73 Try This! Try drawing one shape with your left hand and one with your right hand, simultaneously. BBC


75 Non-Split Brains People with intact brains also show left-right hemispheric differences in mental abilities. A number of brain scan studies show normal individuals engage their right brain when completing a perceptual task and their left brain when carrying out a linguistic task.

76 Brain Organization & Handedness
Is handedness inherited? Yes. Archival and historic studies, as well as modern medical studies, show that the right hand is preferred. This suggests genes and/or prenatal factors influence handedness. OBJECTIVE 20| Discuss the relationship among brain organization, handedness, and mortality.

77 Is it Alright to be Left Handed?
Being left handed is difficult in a right-handed world.

78 Is it Alright to be Left Handed?
The percentage of left-handed individuals decreases sharply in samples of older people (Coren, 1993).

79 Language Functions

80 Aphasia Damage to the left part of the brain in the cerebral cortex
Definition:impaired ability to comprehend or express oneself through language

81 Broca’s Area Prevents a person from producing speech
Person can understand language Words are not properly formed Speech is slow and slurred

82 Wernicke’s Area Loss of ability to understand language
Person can speak clearly, but the words that are put together make no sense. “Word salad” because it appears that the words are all mixed up like the vegetables in a salad


84 Would you rather have Broca’s aphasia or Wernicke’s aphasia? Why?
Journal Would you rather have Broca’s aphasia or Wernicke’s aphasia? Why?

85 Alzheimer’s Disease

86 Alzheimer’s Disease A progressive form of mental deterioration that may affect as many as 4 million Americans Connected with aging but it is a disease and NOT part of a normal aging process

87 Alzheimer’s Disease Characterized by progressive deterioration in mental processes such as memory, language, and problem solving Seriously impairs vocational and social functioning

88 Alzheimer’s Disease Memory loss:
difficult to recall basic info (zip codes, telephone #s, names of grandchildren, addresses) Large gaps in memory for recent events May fail to recognize familiar people or forget their names

89 Alzheimer’s Disease Continue..
May not recognize themselves in the mirror Unable to recall names of their school, birthplace, parents No longer able to speak in full sentences and limit their verbal responses to a few words

90 Alzheimer’s Disease Subtle personality changes: signs of withdrawal or irritability May need assistance to manage everyday tasks (selecting clothes to wear) Difficulties in personal functioning (using bathroom and washing themselves)

91 Alzheimer’s Disease May pace or fidget or display aggressive behavior (yelling, hitting, throwing) May wander off and not be able to find their way back 1 in 3 show signs of hallucinations or delusions

92 Alzheimer’s Disease Severe cases:
People become helpless-unable to communicate or walk and require help in toileting and feeding.

93 Alzheimer’s Disease Discovered by German physician Alois Alzheimer
Found brain abnormalities in a 56-year old woman with dementia

94 Brain Abnormalities 1) Plaques: destroy brain tissues which leads to loss of memory function, confusion, and other symptoms 2) Tangles: twisted bundles of nerve cells

95 Biochemical Reduced levels of acetylcholine (ACh): reflect loss of brain cells and can lead to brain trauma, aluminum poisoning Reduced metabolic rates Negative correlation between cognitive performance and metabolic rate

96 Genetic Transmission 90% of people who inherit a key gene from both parents contract Alzheimer’s disease by the age of 75 Chemotherapy is used to heighten ACh levels Researchers are hopeful that genetic studies may lead to effective medications

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