Module Four

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Module Four

• Incredible Nervous System

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STUDYING THE LIVING BRAIN

• Brain Scan and Cognitive NeuroScience
• MRI
• magnetic resonance imagery
• involves passing nonharmful radio frequencies
  through the brain
• fMRI
• functional magnetic resonance imaging
• measures the activity of specific neurons that
  are functioning during cognitive tasks, such as
  thinking, listening
• PET scan
• positron emission tomography
• involves injecting a slightly radioactive
  solution into the blood and then measuring the
  amount of radiation absorbed by brain cells
  called neurons
• CAT scans
• Computerized axial tomography
• A brain-scanning technique that produces
  three-dimensional computer-generated images of
  the structure of the brain by combining a series
  of X-ray photographs from different angles.

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ORGANIZATION OF THE BRAIN

• Major divisions of the nervous system
• central nervous system - CNS
• peripheral nervous system PNS
• Central nervous system - CNS
• made up of the brain and spinal cord

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ORGANIZATION OF THE BRAIN

• Peripheral nervous system - PNS
• includes all the nerves that extend from the
  spinal cord and carry messages to and from
  various muscles, glands, and sense organs located
  throughout the body
• Subdivisions of the PNS
• somatic nervous system
• autonomic nervous system ANS
• sympathetic division
• parasympathetic division

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ORGANIZATION OF THE BRAIN

• Somatic nervous system
• network of nerves that connect either to sensory
  receptors or to muscles that you can move
  voluntarily, such as muscles in your limbs, back,
  neck, and chest
• Autonomic nervous system - ANS
• regulates heart rate, breathing, blood pressure,
  digestion, hormone secretion, and other functions
• a Sympathetic division
• triggered by threatening or challenging physical
  or psychological stimuli, increases physiological
  arousal and prepares the body for action
• b Parasympathetic division
• returns the body to a calmer, relaxed state and
  is involved in digestion

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ORGANIZATION OF THE BRAIN

• Forebrain
• largest part of the brain
• has right and left sides called hemispheres
• hemispheres are responsible for a number of
  functions, including learning and memory,
  speaking and language, emotional responses,
  experiencing sensations, initiating voluntary
  movements, planning, and making decisions

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ORGANIZATION OF THE BRAIN

• Midbrain
• has a reward or pleasure center, which stimulated
  by food, sex, money, music, looking at attractive
  faces, and some drugs (cocaine)
• has areas for visual and auditory reflexes
• contains the reticular formation, which arouses
  the forebrain so that it is ready to process
  information from the senses

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ORGANIZATION OF THE BRAIN

• Hindbrain
• Has three distinct structures
• Pons
• Medulla
• Cerebellum
• Pons
• functions as a bridge to interconnect messages
  between the spinal cord and brain
• produces chemical involved in sleep
• Medulla
• located on top of the spinal cord
• includes a group of cells that control vital
  reflexes, such as respiration, heart rate, and
  blood pressure
• Cerebellum
• located in the very back and underneath the brain
• involved in coordinating motor movements but not
  in initiating voluntary movements

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CONTROL CENTERS FOUR LOBES

• Frontal lobe functions
• motor cortex
• narrow strip of cortex that is located on the
  back edge of the frontal lobe and extends down
  its side
• involved in the initiation of all voluntary
  movements
• right side controls left
• left side controls right
• organization and function of motor cortex

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CONTROL CENTERS FOUR LOBES

• Parietal lobe function
• location of somatosensory cortex
• narrow strip of cortex that is located on the
  front edge of the parietal lobe and extends down
  its side
• Other functions of parietal lobe
• involved in several cognitive functions,
  including recognizing objects, remembering items,
  and perceiving and analyzing objects in space

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CONTROL CENTERS FOUR LOBES

• Temporal lobe functions
• located below the parietal lobe and is involved
  in hearing, speaking coherently and understanding
  verbal and written material
• Primary auditory cortex
• located on top edge of each temporal lobe,
  receives electrical signals from receptors in the
  ears and transforms these signals into meaningful
  sound sensations, such as vowels and consonants
• Auditory association area
• located directly below the primary auditory
  cortex
• transforms basic sensory information, such as
  noises or sounds, into recognizable auditory
  information, such as words or music

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Temporal Lobe Function

• Brocas area - frontal lobe
• located in left frontal lobe
• necessary for combining sounds into words and
  arranging words into meaningful sentences
• Wernickes area-temporal lobe
• located in the left temporal lobe
• necessary for speaking in coherent sentences and
  for understanding speech

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CONTROL CENTERS FOUR LOBES

• Occipital lobe functions
• vision
• primary visual cortex
• located at the very back of the occipital lobe
• receives electrical signals from receptors in the
  eyes and transforms these signals into
  meaningless basic visual sensations, such as
  lights, lines, shadows, colors, and textures
• visual association area
• transforms basic sensations, such as lights,
  lines, colors, and textures, into complete,
  meaningful visual perceptions, such as persons,
  objects, or animals

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LIMBIC SYSTEM OLD BRAIN

• Hypothalamus
• regulates many motivational behaviors, including
  eating, drinking, and sexual responses emotional
  behaviors such as arousing the body when fighting
  or fleeing, and secretion of hormones, such as
  occurs at puberty
• Amygdala
• located in the tip of the temporal lobe
• receives input from all the senses
• evaluates the emotional significance of stimuli
  and facial expressions, especially those
  involving fear, distress, or threat

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LIMBIC SYSTEM OLD BRAIN

• Thalamus
• gathers and processes information from the senses
• involved in receiving sensory information, doing
  some initial processing, and then relaying the
  sensory information to areas of the cortex
• Hippocampus
• curved structure inside the temporal lobe
• Involved in saving many kinds of fleeting
  memories by putting them into permanent storage
  in various parts of the brain

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Endocrine System

• Endocrine System
• Made up of numerous glands that are located
  throughout the body. Glands secrete various
  chemicals called hormones.
• Pituitary
• Pancreas
• Thyroid
• Adrenal glands
• Gonads

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Endocrine System

• Pituitary gland
• hangs below the hypothalamus
• divided into anterior and posterior
• Posterior
• rear portion
• regulates water and salt balance
• less common form of diabetes
• Anterior
• front portion
• regulates growth through secretion of growth
  hormone
• produces hormones that control the adrenal
  cortex, pancreas, thyroid, and pancreas

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Endocrine System

• Pancreas
• regulates the level of sugar in the bloodstream
  by secreting insulin
• Thyroid
• located in the neck
• regulates metabolism through secretion of
  hormones
• Adrenal glands
• secretes hormones that regulate sugar and salt
  balance
• secretes two hormones that arouse the body to
  deal with stress and emergencies
• epinephrine (adrenaline)
• norepinephrine (noradrenaline)

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Endocrine System

• Gonads
• Females
• ovaries produce hormones that regulate sexual
  development, ovulation, and growth of sex organs
• Males
• testes produce hormones that regulate sexual
  development, production of sperm, and growth of
  sex organs