Ch. 1 The Human Body: An Orientation

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Ch. 1 The Human Body An Orientation
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An Overview Levels of Organization
Maintaining Life

• Reading pages 2-8

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An Overview of Anatomy and Physiology

• Anatomy is
• the study of the structure of body parts and
  their relationships to each other.
• Means to cut apart
• Physiology is
• the study of the function of the bodys structure.

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Topics of Anatomy cont.

• 4 branches of anatomy
• Gross anatomy
• Microscopic
• Developmental
• Specialized branches
• Gross anatomy -
• Macroscopic
• Study of structures large enough to be seen with
  the naked eye

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Gross anatomy

• 3 categories of gross anatomy
• Regional
• study of all body structures in a body region
• Systemic
• study of all structures in a body system
• body is studied system by system
• Surface
• study of internal body structures as they relate
  to the skin

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Topics of Anatomy cont.

• Microscopic
• Study of structures that are too small to see
  with the naked eye
• 2 categories of microscopic anatomy
• Cytology
• Study of cells
• Histology
• Study of tissues

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Topics of Anatomy cont.

• Developmental
• Study of the change in body structures over the
  course of a lifetime
• Embryology
• Developmental changes that occur before and after
  birth
• Helps to explain birth defects

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Topics of Anatomy cont.

• Specialized branches of anatomy
• Pathology
• Study of structural changes associated with
  disease
• Radiology
• Study of internal structures using specialized
  visual techniques
• Molecular
• Study of biological molecules

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Topics of Anatomy cont.

• Essential tools for studying anatomy
• Mastery of anatomical terminology
• Observation
• Manipulation
• Palpation (feeling organs with your hands)
• Auscultation (listening to organ sounds with a
  stethoscope)

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Physiology Complementarity

• Physiology
• Studies the function or operation of organ
  systems
• Focuses/depends on
• Cellular or molecular level
• Principles of physics
• Complementarity of structure and function -
• States that function is dependent on structure
• The form of a structure relates to its function

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Levels of structural organization

• Chemical
• Simplest level of organization
• Atoms
• Tiny building blocks of matter
• Combine to form molecules
• MEET THE ELEMENTS
• Molecules
• Combine specifically to form organelles
• Organelles (nucleus, mitochondria, endoplasmic
  reticulum, etc.) are the basic unit of living
  cells

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Levels cont.

• The cell is the smallest unit of life (cellular
  level), and varies widely in size and shape
  according to the cells function.
• The tissue level is groups of cells having a
  common function.
• Epithelium, muscle, connective, and nervous
• Organ level
• Specific structure composed of two groups of
  tissues that work together to perform a specific
  function
• Lungs epithelial tissue and connective tissue

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Levels cont.

• Organ systems
• Groups of organs that work closely together to
  accomplish a specific purpose
• Cardiovascular system
• Heart, lungs, blood vessels, and blood all work
  together to keep the body oxygenated
• The organismal level is the total number of all
  structures working together to promote life.

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Maintaining life (8 necessary life functions)

• Maintaining boundaries
• Allows the body to maintain separate internal and
  external environments
• Allows the body also maintain separate internal
  chemical environments
• Cells are chemically separate from the body by
  the plasma membrane
• Internal environment kept separate by
  integumentary system (skin)
• Movement
• Allows transport of molecules within the body
• Blood
• Food
• Urine
• Muscles movement

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Maintaining life cont.

• Responsiveness
• Irritability
• Bodys ability to detect changes in the internal
  or external environment and be able respond to
  the stimuli
• Reflex
• Digestion
• Process of breaking down food into molecules that
  the body can use
• Food is broken down into tiny molecules that can
  be absorbed into the blood and used by cells

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Maintaining life cont.

• Metabolism
• All chemical reactions that occur in the body
• Breaking down substances (catabolism)
• Synthesizing more complex substances from simple
  substances (anabolism)
• ATP production
• Regulated by hormones, digestion, and oxygen
  availability
• Excretion
• Process of removing waste (non-useful substances)
• Digestive system
• Urinary system
• Respiratory system

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Maintaining life cont.

• Reproduction
• Process by producing more cells or organisms
• Meiosis and mitosis one cell divides to produce
  identical daughter cells
• Growth
• The increase in size of body parts or the whole
  organism
• Usually accomplished by increasing the number of
  cells
• Individual cells can increase in size when not
  dividing

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ACTIVITY Maintaining life

• Organ systems work cooperatively to promote the
  well-being of the entire body
• Check out pages 6 and 7
• Get into a group of 3 and complete a foldable of
  the 12 organ systems. Must include
• Name of system
• Organs involved
• Brief description of what the system does (do
  your best to put the book description into your
  own words)

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Survival needs

• Survival needs
• Factors that are required to maintain life
• Include
• Nutrients
• Oxygen
• Water
• Body temperature
• Atmospheric pressure

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Survival needs cont.

• Nutrients
• Chemical substances used for energy and the
  rebuilding of cells
• Plant-derived food
• Carbohydrates bodies energy source
• Minerals vitamins required for chemical
  reactions oxygen transport
• Animal foods
• Proteins fuel for the body but less energy than
  carbs help for cell structure rebuilding
• Fats cushion organs, energy reserve, and form
  insulating layers

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Survival needs cont.

• Oxygen
• Human cells need oxygen to perform reactions
• Cells reactions are oxidative requiring oxygen
• Transported by red blood cells
• Air 20 oxygen transported to cells through
  the respiratory system by blood cells
• Water
• Most abundant chemical substance in the body
• 60-80 of body is water
• Chemical reactions need watery environment to
  perform
• Provides base for body secretions and excretions
• Acquired from food and liquids
• Lost from evaporation through the lungs, skin
  excretions

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Survival needs cont.

• Normal body temperature
• Must be maintained for chemical reactions to take
  place
• Body temp must stay above 98ºF for chemical
  reactions to occur at a normal rate
• Body temp that gets too high can cause chemical
  reactions to occur at such a rapid rate that the
  body cant continue to function
• Most body heat is generated from the muscular
  system

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Survival needs cont.

• Atmospheric pressure
• Force the air exerts on the surface of the body
• Breathing and gas exchange
• High altitudes lower atmospheric pressure
  lower cellular functions
• Must be present in appropriate amounts or
  cellular functions can be slow or excessive
  pressure can cause cellular damage

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Homeostasis

• Reading pages 8-12

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Homeostasis

• Homeostasis is the ability of the body to
  maintain a relatively constant internal
  environment, regardless of environmental changes.
  
• A dynamic state of equilibrium or balance
• Internal conditions vary but always remain within
  normal limits
• Communication throughout the body is essential
• Accomplished by the nervous and endocrine systems
  

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Homeostatic control mechanisms

• Homeostatic control mechanisms
• Components
• Variables
• the regulated factor or event
• Receptor
• structure that monitors changes in the
  environment
• sensor that responds to changes or stimuli
• sends info to the control center
• Control center
• Structure that determines the set point (level or
  range) for a variable
• Analyzes input
• Coordinates an appropriate response to the
  stimuli
• Effector
• Structure that carries out the response directed
  by the control center

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Homeostatic control
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Negative feedback mechanism

• Most homeostatic control mechanisms are negative
  feedback mechanisms.
• A negative feedback mechanism causes the variable
  to change in a way that opposes the initial
  change.
• Cause the variable to change in the direction
  opposite to that of the initial change returns
  it to its ideal value
• Ex. Thermostat sets temp houses both the
  receptor control center temp is set and when
  the temp drops the heating system turns on
  (effector) when the temp is reached the
  thermostat is triggered off

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Negative feedback mechanism cont.

• Both the nervous system and the endocrine system
  are important to the maintenance of homeostasis.
• The goal of negative feedback mechanisms is to
  prevent sudden, sever changes in the body.
• Examples
• Body temperature, withdrawal reflex,
• control of blood volume by ADH, heart rate,
• blood pressure, rate and depth of breathing, and
• blood levels of O2, CO2, and minerals

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Negative feedback
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Positive feedback system

• A positive feedback mechanism causes the variable
  to change in the same direction as the original
  change, resulting in a greater deviation from the
  set point
• Response enhances or exaggerates the original
  stimulus so the activity (output) is accelerated
• Said to be positive because the changes occur in
  the same direction as the initial disturbance
• Control infrequent events that dont require
  continuous adjustments

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Positive feedback mechanisms cont.

• Positive feedback mechanisms typically activate
  events that are self-perpetuating
• Once initiated have a amplifying effect
• Most positive feedback mechanisms are not related
  to the maintenance of homeostasis
• They can race out of control so they are rarely
  used to promote day to day life
• Examples
• Blood clotting
• Enhancement of labor contractions oxytocin
  intensifies labor contractions

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Positive feedback
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Homeostatic imbalances

• Homeostatic imbalances often results in disease
• As we age our control systems become less
  efficient stable
• Positive feedback mechanisms can become out of
  control causing illness and diseases (some
  aspects of heart failure are due to out of
  control positive feedback mechanisms)

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The Language of Anatomy

• Reading pages 12-19

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Anatomical position directional terms

• Anatomical position
• A position in which the body is erect (standing),
  feet are slightly apart, palms face forward, and
  the thumbs point away from the body.
• In anatomical position, right and left refer to
  the right and left sides of the person being
  viewed.
• Anatomical position is always assumed
• Directional terms
• Used to explain exactly where one body part is in
  relation to another
• Very specific terminology

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Directional terms
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Directional terms cont.
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Anatomical terminology cont.

• 2 divisions of regional anatomy
• Axial
• Makes up the axis of the body
• Includes head, neck, and trunk
• Appendicular
• The appendages of the body that attach to the
  axis of the body
• Includes upper and lower limbs
• Regional terms designate specific areas within
  the axial and appendicular divisions.
• Designates specific areas within the body
  divisions

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Regional Terms Anterior Posterior Views
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Body planes and sections

• Body planes are flat surfaces that lie at right
  angles to each other
• A section is named for the plane along which it
  is cut
• Sagittal plane sagittal section
• Body planes
• Sagittal
• Frontal
• Transverse

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Body planes cont.

• Sagittal
• A vertical plane that separates the body into
  right and left halves
• Median or midsagittal plane Sagittal plane that
  lies exactly along the bodys midline
• Parasagital Sagittal plane that lies offset of
  the midline
• Frontal
• A vertical plane that separates the body into
  anterior and posterior parts
• Also called a coronal plane
• Divides the body across the crown of the head
• Transverse
• A horizontal plane that runs from right to left
• Divides the body into superior and inferior parts

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Body planes
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Sections

• Sections
• Cuts made along specific planes
• Transverse
• Cross section
• Made along a transverse plane
• Oblique
• Cuts made at angles between the horizontal and
  vertical planes

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Body cavities and membranes

• Body cavities
• Spaces within the body that are closed to the
  outside and contain the internal organs
• Dorsal body cavity
• Space that houses the central nervous system
• Cranial
• Is within the skull houses the brain
• Vertebral
• Spinal cavity
• Cavity within the vertebral column houses the
  spinal cord

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Body cavities
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Body cavities cont.

• Ventral body cavity
• Anterior to larger than the dorsal body cavity
• Thoracic
• Superior division
• Surrounded by ribs and muscles
• Pleural cavities Houses lungs
• Mediastinum Contains the esophagus trachea
• Pericardial cavity - Encloses the heart

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Body cavities cont.

• Ventral body cavities cont.
• Abdominopelvic
• Inferior division of the ventral body cavity
• Separated from thoracic by the diaphragm
• Abdominal cavity
• Contains the stomach, intestines, spleen, and
  liver
• Pelvic cavity
• Inferior part w/ in the bony pelvis
• Contains the bladder, reproductive organs, the
  rectum

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Body cavities
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Membranes

• Serous membranes are also called serosae
• Serous membrane contains
• Parietal
• Lines the cavity walls
• Named for specific cavities in which it is
  associated
• Visceral
• Covers the outer surface of organs in the cavity
• Named for the specific organ in which it is
  associated
• Serous membranes secrete are separated by a
  thin layer of lubrication fluid serous fluid
• allows organs to slide without friction along
  cavity walls and between each organ

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Membranes
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Abdominopelvic Regions and Quadrants

• Helps to divide into smaller areas for study

Figure 1.11a
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Other Body Cavities

• Oral and digestive mouth and cavities of the
  digestive organs
• Nasal located within and posterior to the nose
• Orbital house the eyes
• Middle ear contains bones (ossicles) that
  transmit sound vibrations
• Synovial joint cavities

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Other Body Cavities
Figure 1.13