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The Systems of the Body - PowerPoint

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									The Systems of the Body
    Neuron
   Cell body – source of life of the cell
   Dendrites – branches on the cell bodies that
    act as receivers of messages from adjacent
    neurons.
   Axon – projection through which messages
    travel.
   Synaptic knobs: Tips of branches at end of
    axon. Sends messages to adjacent neurons.
   Synapse: Fluid filled gap between neurons.
  The Nervous System
                                         e os
                                        Nrv u
                                         y te
                                        Ss m


        e tra e o s y te
       Cn l n rv u s s m                            e h ra e o s y te
                                                   Prip e l n rv u s s m
    a s o n ry e e p ls s
  (c rrie v lu ta n rv imu e to
   u c s n k ; a s v lu ta
  ms le a ds in c rrie in o n ry
      p ls s u c s n la d )
   imu e toms le a dg n s


 ra
B in                       pa o
                          S in l c rd    o a e o s y te
                                        S mticn rv u s s m        u n m e o s y te
                                                                 A to o icn rv u s s m
                                             o tro o n ry
                                           (c n lsv lu ta               o tro rg n a
                                                                      (c n lso a sth t
                                                 oe e t)
                                              mv mn                    p ra v lu ta )
                                                                      o e tein o n rily


                                                   y p th tic e o s y te a s ma e e o s
                                                  Sma e n rv u s s m Pra y p th ticn rv u
                                                          o iliz s e o y
                                                        (mb e th b d                        y te
                                                                                           ss m
                                                               rcn
                                                           fo a tio )                     a ta s n
                                                                                       (min in a d
                                                                                       s re q ilib m
                                                                                     re to se u riu )
     Three sections of the brain

                                    Forebrain
Hindbrain     Midbrain              •Diencephalon
•Medulla      •Pathway connecting   •Telecephalon
•Pons         hindbrain and
•cerebellum   Forebrain.



                        Diencephalon  Telecephalon
                        •Thalamus     •Cerebrum
                        •Hypothalamus •Limbic system
    Telencephalon
   Upper and largest portion of the brain
   Involved in higher order intelligence,
    memory, and personality
   Composed of two hemispheres
       Left hemisphere – language processes, etc.
       Right hemisphere – visual imagery,
        emotions, etc.
     Four lobes of the cerebral
     cortex
   Frontal              Parietal         Temporal
•Motor activity    •Bodily sensations,   •Hearing
•Higher level       e.g., pain, heat     •Vision
 intelligence      •Body movement        •Smell
•Planning                                •Memory
•Problem solving
•Emotions                        Occipital
•Self-awareness              •Primary visual
                              area of the brain
Reticular Activating System
and Limbic System
   Reticular activating system runs from
    the medulla through the midbrain into
    the hypothalamus.
       Responsibility for activation of all areas of
        the brain and if damaged – coma ensues
   Limbic system controls emotion
       It has three sub-circuits
    Limbic System - emotions
   Amygdala and hippocampus – essential for
    self-preservation, includes aggression.
   Cingulate gyrus, the septum, and areas of the
    hypothalamus – pleasure and sexual
    excitement.
   Areas of the thalamus and hypothalamus –
    important to socially relevant behaviour
      Diencephalon
                            Hypothalamus
       Thalamus             •Command for the
•Chief relay centre for      control of autonomic
 directing sensory messages functions such as heart
Helps regulate awareness     rate, blood pressure,
•Relays commands going       hunger, thirst.
  to the skeletal muscles   •Role in emotions and
  from the motor cortex.     motivation (e.g., thoughts
                             about fear get translated into
                             arousal through hypothalamus.)
     Three sections of the brain

                                    Forebrain
Hindbrain     Midbrain              •Diencephalon
•Medulla      •Pathway connecting   •Telecephalon
•Pons         hindbrain and
•cerebellum   Forebrain.



                        Diencephalon  Telecephalon
                        •Thalamus     •Cerebrum
                        •Hypothalamus •Limbic system
Cerebellum
   Maintains body balance and
    coordination of movement
       Damage to the cerebellum results motor
        disorders such as ataxia.
       Ataxia is a condition where our movements
        become jerky and uncoordinated.
    Hindbrain continued
   Consists of:
       Pons – involved in eye movement, facial
        expressions and eye movement
       Medulla – controls breathing, heart rate,
        blood pressure
      Midbrain
   Midbrain – top of brain stem, receives
    visual and auditory information, also
    important in muscle movement.
   Reticular formation – controls states of
    sleep, arousal, and attention.
    Spinal cord
   Transmits messages from the brain to the
    other areas of the body.
       Efferent – away from the brain out to the
        body
            Produces muscle action
       Afferent – from the periphery to the brain
            Relays information from the sensory organs
Peripheral Nervous System

   Autonomic nervous system

   Somatic nervous system
Somatic nervous system
   Involved in both sensory and motor
    functions, serving mainly the skin and
    skeletal muscles.
   Efferent impulses: carry messages
    from the brain to the skeletal muscles
   Afferent impulses: carry messages from
    the sensory organs to the brain
Autonomic nervous system
   Controls what is generally involuntary,
    automatic activity

   Consists of the sympathetic and
    parasympathetic nervous systems.
Sympathetic nervous system
   Fight of flight response
       Sends out messages (neurotransmitters) to
        the body preparing the body for fight or
        flight.
   Also prepares the body for strenuous
    activity
Fight or Flight Response
          Increase in                  Decrease in
   Epinephrine &                 Blood flow to the
    norepinephrine                 kidneys, skin and gut
   Cortisol
   Heart rate & blood
    pressure
   Levels & mobilization of
    free fatty acids,
    cholesterol &
    triglycerides
   Platelet adhesiveness &
    aggregation
Parasympathetic nervous
system
   Restores equilibrium in the body

   Decreases arousal, slows breathing and
    heart rate, lowers heart rate and blood
    pressure, etc.
Neurotransmitters
   Electrochemical messengers:
       Catecholamines, consisting of epinephrine
        and norepinephrine
       Dopamine
       Acetycholine
       Serotonin
The Endocrine System
   Set of glands
   Works in close association with the
    autonomic nervous system
   Communicates via chemical substances
    like hormones
   Examples are adrenaline, cortisol,
    somatotropic hormone, gonadotropic
    hormone, etc.
Endocrine and autonomic
systems work together
   Connection between the hypothalamus
    in the brain and the pituitary gland
    (“master gland”)
   The pituitary gland sends out hormones
    that communicates with other glands to
    send out hormones
Adrenal gland
   Located on top of each kidney
   Comprised of the adrenal medulla and
    the adrenal cortex.
       Adrenal medulla secretes adrenaline
        (epinephrine) and noradrenaline
        (norepinephrine)
       Adrenal cortex secretes steroids (including
        mineralocorticoids and glucocorticoids,
        androgens, and estrogens)
Thyroid gland
   Located in the neck
   Produces hormone (thyroxin) that regulates
    activity level and growth.
   Hypothyroidism: Insufficient thyroid
    hormones (leads to low activity levels and
    weight gain)
   Hyperthyroidism: Over-secretion of thyroid
    hormones (leads to hyperactivity and weight
    loss, insomnia, tremors, etc.)
Pancreas
   Located below the stomach
   Regulates level of blood sugar by
    producing insulin which absorbs blood
    sugar.
    Important gland in diabetes mellitus
Digestive system
   Enzymes: break-downs food substances
   Commands from the brain stem
    activates the production of saliva.
    Saliva contains enzymes that
    breakdown starches.
   Esophagus pushes food to the stomach
    using peristalsis.
Digestive system - continued
   Stomach uses gastric juices and churning to
    further breakdown food.
   Peristalsis moves food from the stomach to
    the duodenum (small intestine)
   Acid food mixture becomes chemically
    alkaline from secretions of the pancreas,
    gallbladder, and small intestine wall.
Digestive system - continued
   Additional enzymes and bile continue
    the food breakdown.
   Absorption occurs.
   Large intestine (mainly colon) continues
    absorption of water and passes the
    remaining waste to the rectum for
    excretion.
Disorders of the Digestive
System
   Peptic ulcers – open sores in the stomach or
    duodenum. Causes by excessive gastric juices
    and bacterial infection.
   Hepatitis – liver becomes inflamed.
   Cirrhosis – liver cells die and are replaced by
    scar tissue. Caused by hepatitis and heavy
    alcohol consumption.
Disorders of these Systems
Diabetes
   Type I – insulin-dependent diabetes where
    person has to take exogenous insulin to make
    up for the lack of insulin produced by the
    pancreas.
   Type II – non-insulin dependent diabetes
    where body is not sufficiently responsive to
    insulin
   Leading cause of blindness in adults and 50%
    of dialysis patients (kidney failure) have
    diabetes.
Respiratory System
   Air enters the body through the nose
    and mouth.
   It travels past the larynx and down the
    trachea and bronchial tubes into the
    lung.
   Bronchial tubes divide into small
    branches called bronchioles, and then
    tiny sacs call alveoli.
Disorders of the Respiratory
System
   Asphyxia – too little oxygen and too much
    carbon dioxide (can occur in small breathing
    space).
   Anoxia – shortage of oxygen (occurs at very
    high altitudes). Person looses judgment,
    pass into comma.
   Hyperventilation – deep rapid breaths that
    reduce the amount of carbon dioxide.
Disorders of the Respiratory
System - continued
   Hay fever – seasonal allergic reactions.
    Body produces histamines in response
    to the irritants entering the lungs.
   Asthma – more severe allergic reaction.
    Muscles surrounding the air tubes
    constrict.
   Viral infections (e.g., flu)
   Bacterial infections (e.g., strep throat)
Cardiovascular System
   Transport system of the body.
   Consists of the heart, blood, and blood
    vessels
   Blood vessels consist of:
       Arteries that carry oxygenated (red) blood
        from the heart to the periphery and brain.
       Veins carries de-oxygenated (blue) blood
        back to the heart and lung
Heart
   Fist-sized muscle that circulates blood
    to and from the lungs to the body.
   Four chambers – atrium (right & left)
    and ventricles (right & left)
   Left side pumps oxygenated blood from
    lungs out to periphery and brain.
   Right side takes deoxygenated blood in
    to the lungs.
Blood pressure (BP)
   Pressure of blood in the arteries.
   As the heart contracts and pushed
    blood into the arteries (systolic cardiac
    cycle) the BP rises.
   As the heart rests between beats and
    no blood is pumped (diastolic cardiac
    cycle) BP is at its lowest.
Dynamics of Blood Pressure (BP)
   Cardiac output – force of contraction of
    the heart muscle
   Heart rate – speed of contraction
   Blood volume – amount of blood in the
    system
   Peripheral resistance – ease with which
    blood can pass through the arteries (as
    resistance increases, BP increases)
Dynamics of Blood Pressure (BP)
   Elasticity – is the give and take in the
    arterial walls. As elasticity decreases BP
    increases.
   Viscosity – thickness of the blood. BP
    increases when the thickness of the
    blood increases.
    Blood pressure (BP) is Dynamic
   When arteries dilate (e.g., in heat)
    diastolic BP decreases.
   BP increases when heart rate or cardiac
    output increases in response to activity,
    change in posture, while talking, when
    under stress, temperature, etc.
   BP follows a circadian (daily) rhythm such
    that it is lowest when in deep sleep.
Hypertension
   Permanently high blood pressure
       Systolic blood pressure >= 140 mmHg
       Diastolic blood pressure >= 90 mmHg
   Essential (primary) – no known physical
    cause (90-95% of cases are of this
    type)
   Secondary hypertension – due to
    specific cause, e.g., adrenal tumor.
Risk Factors for Essential
Hypertension
   Lack of exercise      Age
   Body weight           Gender
   Salt consumption      Ethnicity (blacks at
   Stress                 higher risk)
                          Genetics
Blood
   Two components
       Formed elements
       Plasma
   Formed elements consist of three
    elements:
       Red blood cells
       Leukocytes (white blood cells)
       Platelets
Formed Blood –
Red Blood Cells
   Most abundant cells
   Formed in bone marrow
   Contains hemoglobin – a protein that
    attaches to oxygen and transports it to
    the cells and tissue
   Anemia is when level of red blood cells
    are below normal
Leukocytes (white blood cells)
   Serve a protective function (e.g.,
    destroys bacteria).
   Produced in bone marrow and various
    organs of the body.
   Leukemia is when there is an excessive
    production of white blood cells that
    crowd out plasma and red blood cells.
Platelets
   Granular fragments that can clump
    together to prevent blood loss at site of
    cuts.
   Produced by bone marrow
   Hemophilia is when platelets don’t
    function properly to produce clotting
    and so if the person receives a cut
    could bleed excessively.
Plasma
   55% of the blood is plasma
   Composed of 90% water and 10%
    plasma protein and other organic and
    inorganic substances.
   Other substances include hormones,
    enzymes, waste products, vitamins,
    sugars, fatty material etc.
Plasma - continued
   An important fatty substance is lipids.
   Consist of:
       Cholesterol
       Low and high-density lipoprotein
       Triglycerides
   High lipid content in the plasma can lead to
    plaque build-up on arteries and lipid deposits
    in arterial wall, causing hardening of the
    arteries.
Disorders of the Cardiovascular
System – Hardening of Arteries
   Atherosclerosis – deposits of cholesterol
    and other substances on the arterial
    wall, forming plaques that can block the
    artery.
   Ateriosclerosis – calcium and other
    substances get deposited on the arterial
    wall leading to hardening of the
    plaques.
Risk Factors for Atherosclerosis
   Hypertension
   High fat intake leading to hyperlipidemia
   Smoking
   Stress
   Diabetes,
   Lack of exercise
   Genetics
   Gender
         Stress and Atherosclerosis
         Coronary Artery Plaque in
         Monkeys
          0 .8

          0 .7

          0 .6
Plaque
Area      0 .5

(mm2)     0 .4                              D o m in a n t

          0 .3                              S u b o rd in a te

          0 .2

          0 .1

            0
                 S ta b le   U n sta b le
         Stress and Atherosclerosis
         Coronary Artery Plaque in
         Monkeys
          0 .8

          0 .7

          0 .6
Plaque
Area      0 .5

(mm2)     0 .4                                  D o m in a n t

          0 .3                                  S u b o rd in a te

          0 .2

          0 .1

            0
                 T re a te d   U n tre a te d
     Consequences of Atherosclerosis

   Angina pectoris – insufficient oxygen supply
    to the heart for its need and removal of
    waste products resulting in chest pain.

   Myocardial infarction (heart attack) – when
    there is a blockage of blood supply to an area
    of the heart cutting off oxygen supply to the
    tissue in the area and resulting in tissue
    death
Immune System
The Immune System
   Antigens are any substance (e.g., bacterial,
    viral, fungi) that can trigger an immune
    response.
   Bacterial – microorganisms in the
    environment. Grow rapidly and compete with
    our cells for nutrients.
   Fungi – organisms like mould and yeast.
    Also, absorbs nutrients.
   Viruses – proteins and nucleic acid. They
    take over the cell and generate their own
    genetic instructions.
Immune System
   Immune system recognizes itself and
    foreign material
   Transplant success can by increased by:
       Using close genetic tissue match.
       Using medications that inhibit the immune
        system’s attack on the foreign material.
Immune System
   Allergies are immune response to
    (normally) harmless substances.

   Allergins are substances that trigger an
    allergic response (e.g., pollen, cat
    dander)
Organs of the Immune System
   Lymphatic and lymphoid organs
       Deploys lymphocytes
   Lymphocytes
       White blood cell that provides main
        defense against foreign material
       Produced by bone marrow
Organs of the Immune System
   Lymphocytes
       Form of white blood cells that provide main
        defense against foreign matter
   Lymphocytes originate from bone
    marrow
    Organs of the Immune System
   Lymph Nodes
       Bean-shaped spongy tissue
       Largest are in the neck, arm-pit, abdomen, and
        groan
       Filters to capture antigens (foreign material) and
        has compartments for lymphocytes.
   Lymph vessels
       Connects to lymph nodes and carries fluid called
        lymph into the blood stream
        Organs of the Immune System

   Spleen
       Upper left side of the abdomen
       Filters antigens that the lymph vessels put
        into the bloodstream
       Home base for white blood cells
       Removes worn out red blood cells
Soldiers of the Immune
System
   Phagocytes
       Engulf and ingest antigens
   Two types:
       Macrophages – attach to tissue and stay
        there
       Monocytes – circulate in the blood
   Nonspecific immune processes
Specific Immune Processes
   Cell-mediated immunity
   Killer t-cells (CD8) – destroy foreign
    tissue, cancerous cells, cells invaded by
    antigens
   Memory t-cells – remember previous
    antigen in order to defend against
    subsequent invasions.
    Specific Immune Processes
   Delayed hypersensitivity t-cells – involved in
    delayed immune reactions. Produce
    lymphokines that stimulate other t-cells to
    grow, reproduce and attack.
   Helper t-cells (CD4 cells) – get information of
    invasions and report to spleen and lymph
    nodes to stimulate lymphocytes for attack.
   Suppressor t-cells – slow down or stop
    immune processes.
Immune System
   Antibodies – proteins produced in the
    body in response to antigens. They
    combine chemically with antigens to
    overcome their toxic effects.
   B lymphocytes – secrete antibodies
    that protect body against bacterial
    infection and viral infections.
   Immune Response
Foreign    Cough        Phagocytes           Interlukin-1
material   Sneeze       engulf it

                                     Th
                                     cells



           Gamma-                 Killer
           interferon   B cells   Tc cells
    Why Can’t We Fight Cancer
   Some cancer cells release substances
    that suppress the immune response.

   Some antigens may be difficult for the
    immune system to recognize.
    Less Than Optimal Defenses
   Immune function changes during the lifespan,
    increasing in childhood and decreasing in old
    age.
   Unhealthy lifestyles impair immune
    functioning
       Insufficient vitamin A or E decrease production of
        lymphocytes and antibodies
       Vitamin C in important in effectiveness of
        phagocytes
       High fat and cholesterol intake impair immune
        functioning
       Poor sleep impairs immune functioning
    Diseases of the Immune
    System
   Autoimmunity Disorders
       Immune response attacks its own tissue
   Arthritis
   Rheumatic fever
   Multiple sclerosis
   AIDS
     Stress and the Immune
     System
   Stress appears to suppress the immune
    response.
   Killer T-cells are lower during periods of high
    stress.
   Adrenaline and cortisol that are released
    during stress appear to increase suppressor
    T-cells, decrease helper T-cells, and decrease
    functioning of phagocytes and lymphocytes.
   Chemicals released by our nerves suppress
    immune functioning in nearby cells.
    Please answer anonymously
    these questions
   What is the main thing you learned from this
    lecture?
   What is the main question you have that wasn’t
    answered?
   The things the instructor did best …OR the best
    things about the lecture that were?
   The things the instructor did worst …OR the
    worst things about the lecture that were?

								
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