Download 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 related
 Parts of body are well organized
 Each part has a job to do to make the body
operate as a whole
 Structure 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 things
 Tissues – 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 System
 The external covering of the body (skin)
 Protection/waterproofing/regulate body temp

Skeletal System
 Consists of bones, cartilages, ligaments, joints
 Supports body/provides framework for muscles

Muscular System
 All movement relies on muscle contraction
 Only includes skeletal muscles

Nervous System
 Body’s fast-acting control system
 Consists 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 System
 Consists of heart and all blood vessels
 Carries oxygen, nutrients, hormones, and other
substances to body tissues in the blood

Lymphatic System
 Role is to complement the cardiovascular system
 Help 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 System
 Breaks down food to deliver the nutrients to the
blood and removes any extra solid waste
 Includes 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 System
 Exists 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 Boundaries
 Inside remains distinct from outside
 Cellular membranes/Integumentary System

Movement
 Includes all the activities promoted by the
musculo-skeletal system
 Also includes internal movement
○ Blood, food, waste

Responsiveness/Irritability
 The ability to sense changes in the environment
and then react to them
 Major responsibility of the nervous system

Digestion
 The process of breaking down ingested food into
simple molecules that can then be absorbed into
the blood

Metabolism
 Broad term that refers to all chemical reactions
that occur within body cells
 Depends on digestive and respiratory system
 Regulated chiefly by hormones secreted by the
endocrine system (Cortisol)

Excretion
 The process of removing wastes from the body
 Urine/feces

Reproduction
 Production of offspring on cellular level as well as
organismal level
 Regulated very precisely by hormones of the
endocrine system (testosterone/estrogen)

Growth
 An increase in size
 Cell constructing activities must occur at a faster
rate than cell destroying activities
 Hormones 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

Water
 Makes up 60-80% of the human body
 Thirst/Dehydration/Hyper-hydration

Nutrients/Food
 Needed for energy and cell building
 Carbohydrates/Proteins/Fats/Minerals/Vitamins

Oxygen
 All 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 same
 Virtually 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. Effector
 Provides the means for the control center’s
response

Negative Feedback Mechanisms
 Majority of control mechanisms
 Net effect is to shut off the original stimulus
 Think of heating/AC system in a house

Positive Feedback Mechanisms
 Rare in the human body
 Typically 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 Position
 Standing 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; above
 Inferior – away from the head end; below
 Anterior (Ventral) – toward the front of the body
 Posterior (Dorsal) – toward the backside of the body
 Medial – toward the midline of the body; inner side
 Lateral – 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 surface
Deep (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 Cavity
 Contains 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

The abdomino-pelvic cavity can be further
broken down into 9 regions:
 Umbilical Region
 Epigastric Region
 Hypogastric (pubic) Region
 Right and Left Iliac/Inguinal Regions
 Right and Left Lumbar Regions
 Right and Left Hypochondriac Regions