CHAPTER 1 â THE HUMAN BODY: AN ORIENTATION
AN OVERVIEW OF ANATOMY
â Anatomy - study of the structure of the human body.
â Morphology â science of form.
â Physiology â study of body function.
Branches of anatomy
Gross anatomy ï study of body structures that can be examined by the naked eye.
â Important technique: dissection ï connective tissue is removed from between
â Regional anatomy â all structures in a single body region are examined in a
â Systemic anatomy â all organs with related functions are studied together.
â Surface anatomy â study of shapes and markings on the surface of the body that
reveal the underlying organs.
Microscopic anatomy/histology ï study of structures that are so small they can only be
seen with a microscope e.g., cells, tissues etc.
â Developmental anatomy â traces structural changes that occur in the body
throughout the lifespan and the effects of aging.
â Embryology â study of how body structures form
â Pathological anatomy â structural changes in cells, tissues etc caused by
â Radiographic anatomy â study of internal body structures by means of X-ray
â Functional morphology â functioning properties of body structures and assesses
the efficiency of their design.
Hierarchy of structural organization
â Chemical level â atoms combine to form molecules
â Cellular level â cells and organelles are the building blocks of life
â Tissue level â group of cells work together to perform a common function
â Organ level â contain all 4 tissue types
â Organ system â organs work together to accomplish a common purpose.
â Organismal level â whole living person
GROSS ANATOMY: INTRODUCTION
Regional and directional terms
â Anatomical position - common visual reference point.
o Stand with feet together, palms facing anteriorly, thumbs pointing away
o Right and left refer to the sides of the cadaver you are viewing.
â Regional terms â names of specific body areas:
o Axial region â makes up main axis of the body: head, neck and trunk
ï§ Trunk ï thorax (chest), abdomen, and pelvis, and perineum. o Appendicular region â consists of limbs/appendages/extremities.
Body planes and sections
â Body is sectioned/cut along a plane:
o Frontal/coronal plane â vertical; divides body into anterior (ventral) and
posterior (dorsal) parts
o Transverse/horizontal plane â horizontal from right to left; divides body
into superior and inferior parts.
o Sagittal planes â vertical but divide body in right and left parts.
ï§ Midline is the median/midsagittal plane
ï§ Other sagittal planes offset from midline are parasagittal.
ï§ Oblique sections â cuts made along any plane that lies diagonally
between the horizontal and the vertical.
Orientation and directional terms
Superior (cranial) Toward the head end or upper part of a body structure; above
Inferior (caudal) Away form the head end or toward lower part of body
Anterior (ventral) In front of
Posterior (dorsal) Behind
Medial Inner side of; toward or at midline
Lateral Away from midline; outer side of
Proximal Closer to origin of the body part of point of attachment of a
limb to the body trunk
Distal Farther from the origin of a body part or point of attachment of
limb to body trunk
Superficial (external) Toward or at body surface
Deep (internal) Away from the body surface; internal
Ipsilateral On same side (e.g., right hand and foot)
Contralateral On opposite sides
The human body plan
All vertebrates share the following basic features:
â Tube within a tube body plan ï inner tube from mouth to anus; outer tube of axial
skeleton and associated axial muscles
â Bilateral symmetry ï right side is mirror image of left.
â Dorsal hollow nerve cord ï along midline; develops into brain and spinal cord
â Notochord and vertebrae
â Segmentation ï ribs in humans is evidence of this
â Pharyngeal pouches
Body cavities and membranes
â Dorsal body cavity
o Cranial cavity â lies in the skull and encases the brain
o Vertebral cavity â runs through the vertebral column to enclose spinal
â Ventral body cavity ï more anterior and larger of the body cavities; contains
visceral organs (lungs, heart, intestines and kidneys) o Superior thoracic cavity â surrounded by ribs and muscles of chest wall.
Consists of 3 parts:
ï§ 2 lateral parts, each containing a lung surrounded by pleural cavity
ï§ Central band of organs called mediasti