Introduction to Anatomy
Diane A. Young
Brewbaker Technology Magnet High School
Anatomy
 Anatomy
– study of the structures of the
body
 Physiology
structures
– study of the functions of these
Body Planes
VERTICAL PLANES:
Vertical – up-and-down line at the right angle to the horizon
Midsagittal plane (midline) – the vertical plane that divides
the body, from top to bottom into equal left and right
halves.
Sagittal plane – any vertical plane parallel to the midline
that divides the body into unequal left and right portions.
Coronal plan (frontal) – any vertical plane, at right angles to
the sagittal plane that divides the body into anterior (front)
and posterior (back) portions.
Body Planes
 Horizontal
Planes:
Transverse
plane (horizontal) – divides
the body into superior (upper) and
inferior (lower) portions
A
transverse plane can be at the waist
or any other level of the body
Body Directions

Body directions – relative location of the whole body or an
organ is described through the use of pairs of contrasting
body direction terms.
 Ventral – the front or belly side of the body or organ
 Anterior
– situated in the front. Also, the forward part
of an organ.
 Superior – uppermost, above or toward the head
 Cephalic – toward the head
 Proximal
– situated nearest the midline or beginning of
a body structure
 Medial – direction toward or nearer the midline
Body Directions, cont’d
 Dorsal
– to the back of the body or organ
 Posterior
– situated in the back or on the back part of
an organ.
 Inferior
 Caudal
– lowermost, below, or toward the feet
– toward the lower part of the body
 Distal
– situated farthest from the midline or beginning
of body structure
 Lateral
– the direction toward or nearer the side and
away from the midline
 Bilateral
– relating to, or having, two sides
Examples

Anterior:
 The mouth is anterior to the oral cavity.
 The trachea (windpipe) is anterior to the cervical spine
(vertebrae).
 The skin of the palm is anterior to the wrist bones
(carpals).
 The patella is anterior to the knee joint.

Posterior:
 The oral cavity is posterior to the mouth.
 The cervical vertebrae is posterior to the trachea.
Examples cont’d

Superior:
 The
forehead is superior to the nose.
 The head is superior to the neck.
 The most superior portion of the femur is the
femoral head.
 The humerus is superior to the elbow joint.
 The heart is superior to the diaphragm
 Inferior:
 The
nose is inferior to the forehead.
 The neck is inferior to the head
Major Body Cavities

Dorsal Cavity divided into two parts, protects the
structures of the nervous system that coordinate
the bodily function
 Cranial
cavity – located within the skull,
protects the brain
 Spinal
cavity – located within the spinal
column, protects the spinal cord
Major Body Cavities

Ventral Cavity divided into three parts, contains many of
the body organs that maintain homeostasis. Homeostasis
means maintaining a constant internal environment.
 Thoracic cavity (chest cavity) – protects the heart and
lungs. The diaphragm is a muscle that separates the
thoracic and abdominal cavities.
 Abdominal cavity – contains primarily the major organs
of digestion. Referred to as the abdomen.
 Pelvic cavity – the space formed by the pelvic (hip)
bones. It contains primarily the organs of the
reproductive and excretory systems.
 There is no division between the abdominal and pelvic
cavities. Together they may be referred to as the
abdominopelvic cavity.
Division of the Abdomen

To make it easier to describe where an organ or a pain is
located, the abdomen is divided into four imaginary
quadrants.
 Right
 Left
upper quadrant (LUG)
 Right
 Left
upper quadrant (RUQ)
lower quadrant (RLQ)
Lower quadrant (LLQ)
Regions of the Thorax and Abdomen

Right and left hypochondriac regions. Hypochondriac
means below the ribs. This term also means the
individual with an abnormal and excessive concern about
his/her health.

Epigastric Region – epigastric means above the stomach

Right and left lumbar region. Lumbar refers to the
inward curve of the spine

Umbilical region - The term umbilical means referring to
the umbilicus (belly button or naval).

Right and left iliac regions - Iliac refers to the hipbone.

Hypogastric region - Hypogastric means below the
stomach. The entire lower region of the abdomen is also
referred to as the groin or inguinal area.
Peritoneum

Peritoneum is the membrane that protects and supports
(suspends in place) the organs located in the abdominal
cavity.

Parietal peritoneum – the outer layer of this membrane
that lines the abdominal cavity

Visceral peritoneum – the inner layer of this membrane
that surrounds the organs of the abdominal cavity.
Visceral means relating to the internal organs (those
enclosed within a cavity) especially the abdominal organs.

Mesentery – a layer of the peritoneum that suspends parts
of the intestine within the abdominal cavity.

Retroperitoneal – means located behind the peritoneum
of the abdominal cavity.
Peritoneum, cont’d

Peritonitis – inflammation of the peritoneum.

Ascites – an abnormal accumulation of clear or milky
serous (watery) fluid in the peritoneal cavity.
Cytology

Cytology is the study of the formation, structure, and
function of the cells.

Cell membrane – the structure that surrounds and
protects the cell. A membrane is a thin layer of tissue
that covers a surface, lines a cavity or divides a space or
organ.

Cytoplasm is the material within the cell membrane that
is not part of the nucleus.

Nucleus – is surrounded by the nuclear membrane. It is a
structure within the cell that has two important functions:
Controlling the activities and helps the cell divide.
Cells are the basic structural units of the body that are
specialized and grouped together to form the tissues and
organs.
Tissue

The four main types of tissue are epithelial, connective,
muscle and nerve
 Epithelial
tissue – form a protective covering for all of
the internal and external surfaces of the body.
 Epithelium
– the specialized epithelial tissue that
forms the epidermis of the skin and the surface
layer of mucous membranes.
 Endothelium
– specialized epithelial tissue that
lines the blood and lymph vessels, body cavities,
glands and organs
 Glands
are made up of specialized epithelial tissues
that are capable of producing secretions.
Tissue

Connective tissues support and connect organs and other
body tissues
 Adipose
tissue, also known and fat, provides
protective padding, insulation, support and acts as a
nutrient reserve.
 Loose
connective tissue – surrounds various organs and
supports both nerve cells and blood vessels.
 Blood
 Bone
 We
and lymph are liquid connective tissue
and cartilage are dense connective tissue
will discuss blood, lymph, bone and cartilage later
Tissue

Muscle tissue – contains cell material with the specialized
ability to contract and relax

Nerve Tissue – contains cells with the specialized ability
to react to stimuli and conduct electrical impulses.
Glands

A gland is a group of specialized epithelial cells that form
secretions. A secretion is the substance produced by a
gland.
 Exocrine
glands, such as sweat glands, secrete their
chemical substances into ducts that lead either to
other organs or out of the body.
 Endocrine
glands, which secrete hormones, do not
have ducts. These secretions flow directly into the
bloodstream for transportation to organs and other
structures throughout the body.
Organs

An organ is somewhat independent part of the
body that performs a special function or
functions.

The tissues and organs of the body are organized
into systems that perform specialized functions.