Chapter One The Human Body An Orientation by vjz16565


									Chapter One The Human Body: An Orientation
   I.     An Overview of Anatomy and Physiology
   II.    Levels of Organization
   III.   Maintaining Life
   IV.    Homeostasis
   V.     The Language of Anatomy

A. Topics of Anatomy
    a. Two complementary branches of science
            a. Anatomy – studies the structure of body parts and their relationships to one another (more
                easily visualized)
            b. Physiology – function of the body’s structural machinery, harder to “see”
    b. Topics in Anatomy
            a. Gross (Macroscopic) Anatomy
                      i. Study of large body structures visible to the naked eye
                             1. Heart, lungs and kidneys
            b. Regional –
                      i. Structures in an area
                             1. Muscles, bones, blood vessels, nerves in the leg
            c. Systemic
                      i. System by system
                             1. Cardiovascular system  heart, blood vessels, etc
            d. Surface
                      i. How underlying structures relate to overlying skin surface
                             1. How to draw blood
            e. Microscopic
                      i. Small things in the body
                             1. Cytology – cells in the body
                             2. Histology – tissues
            f. Developmental
                      i. Changes that occur over a lifespan
                     ii. Embryology
                             1. Development before birth
    c. Topics in Physiology
            a. Renal Physiology
                      i. Study of the kidneys
            b. Neurophysiology
                      i. Workings of the nervous system
            c. Cardiovascular Physiology
                      i. Examines the operation of heart and blood vessels
    d. Principle of Complementarity of Structure and Function
            a. Function reflects structure
            b. This is the way we are approaching this material here

                                      Levels of Structural Organization
A. Overview of Levels (fig 1.1) – explain each level
    a. Chemical
    b. Cellular
    c. Tissue
    d. Organ
    e. Organ System (fig 1.2)
    f. Organismal level
                                                Maintaining Life
A. Necessary Life Functions
    a. Important to note that all systems work together (fig 1.3)
    b. Maintaining Boundaries
            a. Most keep the external environment separate from the internal environment
            b. Integumentary system protects from the sun, heat, bacteria, dehydration, etc
    c. Movement
            a. All activities promoted by the muscular system with the help of the skeletal system
            b. Also the movement of food and waste through the body
    d. Responsiveness (Irritability)
            a. Ability to sense changes in the environment
            b. Nervous system is overseer, but all systems are involved
    e. Digestion
            a. Breaking down food into small molecules to absorb
    f. Metabolism
            a. Means a state if change
            b. All chemical reactions in body cells
                      i. Catabolism – breaking down substances into simpler building blocks
                     ii. Anabolism – synthesizing complex cellular structures from simpler substances
                    iii. Cellular Respiration – using nutrients and oxygen to produce ATP
    g. Excretion
            a. Removing wastes; indigestible food, nitrogenous waste (urea), carbon dioxide
    h. Reproduction
            a. Cellular reproduction via mitosis
            b. Organismal reproduction via meiosis
    i. Growth
            a. Increase in size of a body part or an organism
B. Survival Needs
    a. Nutrients
            a. Contain chemical substances used for energy & cell building
            b. Plant –derived – carbohydrates, vitamins, minerals
                      i. Carbohydrates are the major source of energy fuel for the body cells
            c. Animal – derived – protein and fat
                      i. Proteins and fats are used to build cell structures
                     ii. Fats insulate and energy reserves
    b. Oxygen
            a. Reactions that release energy are oxidative, therefore they need oxygen
    c. Water
            a. 60-80% of body in water
            b. Guarantees the appropriate environment for all reactions to occur
    d. Appropriate Temperature
            a. Controls metabolic rates (98)
            b. Too low, slows things down; too high, reactions occur to quickly
    e. Atmospheric Pressure
            a. Important for breathing
            b. High altitudes – pressure is low, air is thin, can have problems maintaining cellular support
A. Def: ability to maintain relatively stable internal condition s even though the outside world changes
    a. Not a static system, very dynamic
              a. But always within borders of acceptability
    b. Involves all systems working together
B. Homeostatic Controls Mechanisms
    a. Communication within the body
    b. Accomplished by nervous system and endocrine system
                i. Use electrical impulses and chemical signals
    c. Steps in the Process (fig 1.4 – draw on the board)
                i. Variable
                        1. Factor of event being regulated
               ii. Receptor
                        1. Sensor that monitors the environment and responds to the stimuli
              iii. Control Center
                        1. Receives info from the receptor and determines level at which the variable is to be
              iv. Effector
                        1. Means for the control centers response to the stimulus
                        2. Follows pathway set by the control center – efferent pathway
               v. Homeostasis is restored
    d. Negative Feedback Mechanism
                i. Most controls are negative feedback
               ii. Home heating system is best example
                        1. Body thermostat is located in the hypothalamus
              iii. Endocrine system and reflex response also work with this system
                        1. Example of endocrine system (fig 1.5)
                                a. High sugar intake leads to product of insulin
                                b. Low sugar leads to production of glucagons
                                          i. Tells liver to release sugar
    e. Positive Feedback Mechanisms
                i. Changes occur in the same direction as the initial disturbance, causing the variable to deviate
                   further from the original value or range
               ii. Can run out of control, so they aren’t used to monitor daily activities
              iii. Examples
                        1. Blood Clotting (fig 1.6)
                                a. Release of platelets triggers the release of more platelets until the blood
                                    vessel is repaired
                        2. Labor contractions during birth
C. Homeostatic Imbalances
    a. If there is a problem with keeping the balance
    b. Mainly caused by disease and aging
                                         Language of Anatomy
A. Anatomical Position and Directional Terms
        i. Anatomical Position
               1. Erect body, feet slightly apart, palms forward
               2. Right and left refer to the body, not the observer
       ii. Directional Terms (Table 1.1)
               1. Superior (cranial) –toward head
               2. Inferior (caudal) – away from the head
               3. Anterior – toward the front
               4. Posterior – toward the back
               5. Medial – toward the midline
               6. Lateral – away from the midline
               7. Intermediate – between medial and lateral
               8. Proximal – closer to trunk
               9. Distal – farther from trunk
               10. Superficial – toward the surface
               11. Deep – away from the surface
B. Regional Terms (fig 1.7)
        i. Axial – head, neck, trunk
       ii. Appendicular - appendages
C. Body Plans and Sections (fig 1.8)
        i. Sagittal – vertical plane dividing body into left and right
               1. Median (Midsagittal) – on midline
               2. Parasagittal – offset from midline
       ii. Frontal –lie vertically, divide body into anterior and posterior
               1. Also called the coronal plane
      iii. Transverse – horizontal plane, divides body into superior and inferior parts
               1. Also called cross sections
               2. Oblique sections are diagonally between horizontal and vertical planes
D. Body Cavities and Membranes
        i. Cavities (fig 1.9)
               1. Dorsal – 2 parts
                         a. Protects the nervous system
                         b. Cranial cavity – skull to encase the brain
                         c. Vertebral cavity (spinal) – to protect spinal cord
               2. Ventral – 2 parts
                         a. Viscera (visceral organs) – all housed in the ventral cavity
                         b. Thoracic – 2 parts
                                    i. Surrounded by the ribs & muscles of the chest
                                   ii. Pleural cavity - lungs
                                  iii. Mediastinum
                                           1. Superior mediastinum – trachea, esophagus
                                           2. Pericardia cavity – encloses the heart
                         c. Abdominopelvic – 2 parts
                                    i. Separated by the diaphragm (muscle)
                                   ii. Abdominal cavity
                                           1. Contains the stomach, intestines, spleen, liver, other organs
                                  iii. Pelvic Cavity
                                           1. Within the bony pelvis
                                           2. Contains the bladder, the reproductive organs & the rectum
       ii. Membranes of the Ventral Body Cavities
               1. Serosa – very thin double-layered membrane (fig 1.10)
                         a. Parietal serosa - Part that lines the cavity walls
                         b. Visceral serosa – lines the organs in the cavity
                         c. Serous fluid keeps the area between the layers
                         d. Layers are named for the organ/area they protect
                                    i. Parietal pericardium lines pericardial cavity
      iii. Other Body Cavities
              1. Oral and digestive cavities – starts with mouth, teeth and tongue, includes all the
                  digestive organs to anus
              2. Nasal Cavity – within and posterior to the nose
              3. Orbital Cavity – houses the eyes in the skull
              4. Middle ear cavities – medial to eardrum, contains bones to transmit vibrations
              5. Synovial cavities – joint cavities, around elbow and knee
                      a. Have lubricant to reduce friction
E. Abdominopelvic Regions and Quadrants (fig 1.11)
        i. Regions – used by regional anatomists
              1. Umblical region
              2. Epigastric region
              3. Hypogastric region
              4. Right and left iliac (inguinal) region
              5. Right and left lumbar region
              6. Right and left hypochondriac region
       ii. Quadrants – used by medical personnel
              1. Right Upper
              2. Left Upper
              3. Right Lower
              4. Left Lower

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