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Transcript of Anatomy and Physiology are complementary sciences that allow one to study, classify, and understand...
CHAPTER 1
THE HUMAN BODY: AN ORIENTATION
Anatomy and Physiology are complementary sciences that allow one to study, classify, and understand body structures and functions.
Overview of Anatomy and Physiology
Anatomy the study of the structure and shape of the body and its parts and their relationship to one another.
Physiology the study of how the body and its parts work or function.
Relationship between Anatomy and Physiology
Anatomy and Physiology are always relatedParts of body are well organizedEach part has a job to do to make the body
operate as a wholeStructure determines what functions can take
place
Levels of Structural Organization
The human body has many levels of structural complexity
Atoms – building blocks of matter; combine to form many various molecules (water, sugar, proteins)
Cells – smallest units of all living thingsTissues – consist of groups of similar cells that
have a common function
Organ – structure composed of two or more tissue types that performs a specific function for the body.
Organ System – a group of organs that work together to accomplish a common purpose.
Organism – highest level of structural organization; sum total of all structural levels working together to keep us alive.
Organ System Overview
There are eleven organ systems that make up the human body.
Integumentary SystemThe external covering of the body (skin)Protection/waterproofing/regulate body temp
Skeletal SystemConsists of bones, cartilages, ligaments, jointsSupports body/provides framework for muscles
Muscular SystemAll movement relies on muscle contractionOnly includes skeletal muscles
Nervous SystemBody’s fast-acting control systemConsists of brain, spinal cord, nerves, and
sensory receptors Endocrine System
Controls the release of hormones through various glands in the body
Includes adrenals, pituitary, thyroid, pancreas, etc.
Cardiovascular SystemConsists of heart and all blood vesselsCarries oxygen, nutrients, hormones, and other
substances to body tissues in the blood Lymphatic System
Role is to complement the cardiovascular systemHelp to clean the blood and hold cells involved in
immunity Respiratory System
Keeps the body constantly supplied with oxygen and removes carbon dioxide
Consists of nasal passages, pharynx, larynx, trachea, bronchi, and lungs
Digestive SystemBreaks down food to deliver the nutrients to the
blood and removes any extra solid wasteIncludes mouth, esophagus, stomach, small/large
intestines, and other complimentary organs Urinary System
Removes the nitrogen-containing wastes from the break down of proteins
Composed of kidneys, ureters, bladder, and urethra
Reproductive SystemExists primarily to produce offspring and pass on
one’s genetic code to the next generation
Maintaining Life: Necessary Life Functions
Organ systems do not work in isolation; instead, they work together to promote the well-being of the entire body.
We will take a look at eight necessary functions of human life
Maintaining BoundariesInside remains distinct from outsideCellular membranes/Integumentary System
MovementIncludes all the activities promoted by the
musculo-skeletal systemAlso includes internal movement
○ Blood, food, waste
Responsiveness/IrritabilityThe ability to sense changes in the environment
and then react to themMajor responsibility of the nervous system
DigestionThe process of breaking down ingested food into
simple molecules that can then be absorbed into the blood
MetabolismBroad term that refers to all chemical reactions
that occur within body cellsDepends on digestive and respiratory systemRegulated chiefly by hormones secreted by the
endocrine system (Cortisol)
ExcretionThe process of removing wastes from the bodyUrine/feces
ReproductionProduction of offspring on cellular level as well as
organismal levelRegulated very precisely by hormones of the
endocrine system (testosterone/estrogen)
GrowthAn increase in sizeCell constructing activities must occur at a faster
rate than cell destroying activitiesHormones of the endocrine system play a large
role (HGH)
Survival Needs
The body requires certain things to maintain life Water Nutrients/Food Oxygen Normal Body Temperature Normal Atmospheric Pressure
WaterMakes up 60-80% of the human bodyThirst/Dehydration/Hyper-hydration
Nutrients/FoodNeeded for energy and cell buildingCarbohydrates/Proteins/Fats/Minerals/Vitamins
OxygenAll chemical reactions that release energy require
oxygen to be present Normal Body Temp/Atmospheric Conditions
Too Cold (Hypothermia)/Too Hot(Fever/Heat Stroke)High Altitude Sickness
Homeostasis
Homeostasis describes the body’s ability to maintain relatively stable internal conditions even though the outside world is continuously changing.State of equilibrium or balance minor things may
change, but the overall picture remains the sameVirtually all organ systems work together to
maintain homeostasis
Homeostatic Controls
Communication between organ systems is essential to maintaining homeostasis. This communication is accomplished mainly by the nervous (electrical signals) and endocrine systems (hormones).
All homeostatic control mechanisms have at least three components. 1. Receptor
Type of sensor that monitors and responds to changes in the environment (stimuli)
Sends this information to the next component 2. Control Center
Analyzes information received from receptor and determines the appropriate response
3. EffectorProvides the means for the control center’s
response
Negative Feedback MechanismsMajority of control mechanismsNet effect is to shut off the original stimulusThink of heating/AC system in a house
Positive Feedback MechanismsRare in the human bodyTypically control infrequent events that occur
explosively and do not require continuous adjustments
Blood Clotting in response to a cut
The Language of Anatomy
Just like most things, anatomy has its own terminology specifically designed to make it easier to identify body locations and regions.
In order to prevent too much confusion, a set of terms were created that allow body structures to be located and identified clearly with just a few words.
Anatomical Position
Before we can accurately describe body parts and position, we need a starting point to reference.
When using these terms, we will always assume the body is in its standard position.
Anatomical PositionStanding up straight, feet shoulder width apart and
parallel to one another, arms hanging at sides with palms facing forward.
Directional Terms
Directional Terms allows people to explain exactly where one body structure is in relation to another structure. (Table 1.1 page 15)
Superior – toward the head end of the body; aboveInferior – away from the head end; belowAnterior (Ventral) – toward the front of the bodyPosterior (Dorsal) – toward the backside of the bodyMedial – toward the midline of the body; inner sideLateral – away from the midline; outer side
Intermediate – between a more medial and more lateral structure
Proximal – close to the origin of the body part or the point of attachment of a limb to the body
Distal – farther from the origin of a body part or point of attachment of a limb to the body
Superficial (external) – toward the body surfaceDeep (internal) – away from the body surface
Body Planes and Sections
Plane an imaginary line through the body. Since the body is 3D, we can refer to three types of planes.
Sagittal – cut along lengthwise dividing the body into right and left parts
Frontal (Coronal) – cut along lengthwise dividing the body into anterior and posterior parts
Transverse – cut along horizontally dividing the body into superior and inferior parts. Also known as a cross-section.
Body Cavities Dorsal Body Cavity
Has two subdivisions○ Cranial cavity – space inside the skull○ Spinal Cavity – extends from cranial cavity to the end of
the vertebral column
Ventral Body CavityContains all the structures within the chest and
abdomen○ Thoracic Cavity – contains lungs, heart, etc○ Abdominal Cavity – contains stomach, liver, intestines, etc.○ Pelvic Cavity – reproductive organs, bladder