Introduction To Human Anatomy And Organization Of Organism

INTRODUCTION TO HUMAN ANATOMY AND ORGANIZATION OF ORGANISM

Term Used in Anatomy and Physiology

Definition of Terms

The word anatomy is derived from a Greek word ( Ana-Tome): meaning cutting up into sections.

Anatomy: It is a study of the body structures and physical relationship involved in between body systems.

• OR

Is the study of the structures and relation between body parts.

Is generally divided into three components:-

• i.Gross (macroscopic) anatomy:
• It is the study of structure as they appear in human body.

ii.Microscopic anatomy:

It is the study of structures by using microscope.The structures include cells ,tissues and molecules

iii.Developmental anatomy

It is the study of the structural changes that occur between conception and adulthood.

Subdivisions of gross anatomy

• i.Surface anatomy
• It is the study of the external form of the body and its relation to deeper structures.
• ii.Regional anatomy
• It is the study of specific regions of the body
• iii.systemic anatomy

It is the study of specific organ systems

Subdivision of microscopic anatomy

Cytology: The study of the structural features of cells using microscope.

Histology: The study of tissues, which are group of cells and the material surrounding them.

Is the study of tissue at microscopic level.

Introduction To Human Anatomy And Organization Of Organism

Physiology: The science of the mechanical, physical, and biochemical functions of humans in good health, their organs and the cells of which they are composed.

Pathology: The medical science dealing with all aspects of disease, with an emphasis on the cause and development of abnormal conditions as well as the structural and functional impairement resulting from disease.

Anatomical Position and Planes

Anatomical Position

All anatomical descriptions are expressed in relation to the anatomical position.

The anatomical position refers to people regardless of the actual position they may be in as if they were standing erect, with their:

Head, eyes (gaze), and toes directed anteriorly (forward)

Upper limbs by the sides with the palms facing anteriorly

Lower limbs close together with the feet parallel and the toes directed anteriorly

ANATOMICAL POSITION

…

Anatomical Planes

Anatomical descriptions are based on four imaginary planes that intersect the body in the anatomical position.

There are many sagittal, frontal, and transverse planes, but there is only one median plane

Introduction To Human Anatomy And Organization Of Organism

Median (median sagittal) plane is the vertical plane passing longitudinally through the centre of the body, dividing it into right and left halves Sagittal planes are vertical planes passing through the body parallel to the median plane.

Introduction To Human Anatomy And Organization Of Organism

It is helpful to give a point of reference to indicate the position of a specific plane for example, a sagittal plane through the midpoint of the clavicle=mid clavicular line Any plane parallel and near the median plane may be referred to as a Para median plane

• Frontal (coronal) planes are vertical planes passing through the body at right angles to the median plane, dividing it into anterior (front) and posterior (back) portion for example, a frontal plane through the heads of the mandible.

. Transverse planes (horizontal) are planes passing through the body at right angles to the median and frontal planes.

A transverse plane divides the body into superior (upper) and inferior (lower) part for example, a transverse plane through the umbilicus is called transumbilical plane

Terms of Relationship and Comparison

The following terminologies describe the relationship of parts of the body in the anatomical position and compare the position of two structures relative to each other Anterior

• In front of, front
• Posterior
• After, behind, following, toward the rear
• Distal
• Away from, farther from the origin (trunk)
• Proximal
• Near, closer to the origin
• Dorsal

Near the upper surface, toward the back

Ventral

• Toward the bottom, toward the belly
• Superior
• Above, over or near to the head
• Inferior
• Below, under or near to the foot (in relation to other structure)
• Lateral
• Toward the side, away from the mid-line
• Medial
• Toward the mid-line, middle, away from the side
• Rostral
• Toward the front of the head (nose/mouth)
• Caudal

Toward the back, toward the tail

….

Cranial

Combined terms describing intermediate positional arrangements

Inferomedial

Nearer to the feet and closer to the median plane for example, the anterior parts of the ribs run inferomedially Superolateral

• Nearer to the head and farther from the median plane

Proximal and distal

Directional terms used when describing positions for example, whether structures are nearer to the trunk or point of origin (i.e. proximal) Dorsum

Superior or dorsal (back) surface of any part that protrudes anteriorly from the body, such as the dorsum of the foot, hand, penis, or tongue

Terms of Laterality

Paired structures having right and left members (e.g., the kidneys) are bilateral, whereas those occurring on one side only (e.g., the spleen) are unilateral. Ipsilateral means occurring on the same side of the body e.g. the right thumb and right great toe.

• Contra-lateral means occurring on the opposite side of the body e.g. the right hand and

the left hand

Structural Organization Levels of Organism

• The body has six structural levels:
• Chemical level
• Cell level
• Tissue level
• Organ level
• System level

Organism level

Chemical level

The chemical level involves the interactions between atoms, which combine to form molecules such as glucose/carbohydrate, water, fats and proteins Cell level

• Cells are the basic units of all living things.

Molecules combine to form organelles, which are the small structure that make up cells The plasma membrane forms the outer boundary of the cell and the nucleus contains the cell‘s hereditary information

Tissue level

A tissue is a group of similar cells and the material surrounding them.

The characteristic of the cells and surrounding material determine the functions of the tissue The numerous different tissues that make up the body are classified into four basic types: epithelial, connective, muscle and nervous.

Organ level

An organ is composed of two or more tissue types that perform one or more common functions The urinary bladder, heart, skin, and eye are examples of organ

Organ system level

• An organ system is a group of organs that have a common function or set of functions
• An organ system are therefore viewed as a unit
• For example. urinary system consists of the kidney, ureter, urinary bladder and urethra

Organism level

An organism is any living thing considered as a whole, whether composed of one cell such as bacterium or of trillions of cells such as human

CHARACTERISTICS OF LIVING ORGANISM

• What are the characteristics of living organisms?
• Human are organisms that share common characteristics with other organisms.

The following are the characteristics of life.

Organization, metabolism, responsiveness, growth, development and reproduction are life‘s essential characteristics

Organization:

Is the condition in which the parts of an organism have specific relationship to each other and the parts interact to perform specific functions For example organism is composed of cells which in turn have specialized organelles which depend on the precise organization of large molecules.

The disruption of this organized state may lead to loss of function of a cell or cell death.

Metabolism

Are all chemical reactions taking place in an organism It includes the ability of an organism to break down food molecules (digestion) and absorption into the body, where are used as a source of energy and raw material for organism to synthesize the organism‘s own molecules Responsiveness

The ability of an organism to sense changes in its external or internal environment and adjust to those changes

Other characteristics includes

• Growth: increase in body size without change in shape
• Reproduction: production of new organism and new cell
• Respiration: obtaining oxygen, removing carbon dioxide and releasing energy from foods
• Excretion: removal of wastes produced

Circulation: movement of substances from place to place in body fluid

Life depend upon the following environmental factors

Water: is the most abundant substance in the body. It is required for a variety of metabolic processes and it provides the environment in which most of them take place Food: refers to substances that provide organisms with necessary chemical (nutrients) in addition to water

Oxygen: is a gas used in the process of releasing energy from nutrients

Heat: is a form of energy from metabolic reactions and it also controls the rate at which these reactions occur.

Pressure: is an application of force on an object or substance.

In human the pressure plays role in breathing, circulation (heart action produces blood pressure which keeps blood flowing through blood vessels)

SUMMARY

Anatomy is a study of structure of the body and physical relationship involved in between body systems.

Physiology is the scientific investigation of the process or functions of living things The anatomical position refers to people regardless of the actual position they may be in as if they were standing erect.

Introduction To Human Anatomy And Organization Of Organism

The body has six structural levels which are Chemical level, Cell level, Tissue level, Organ level, Organ system level and Organism level All anatomical descriptions are expressed in relation to the anatomical position Organization, metabolism, responsiveness, growth, development and reproduction are life‘s essential characteristics

EVALUATION

• Define the terms: anatomy, cytology, histology and physiology
• What are the anatomical position and planes
• What are the Structural levels of the human body

What are the characteristics of life

References

Keith L. Moore (2016) The deeloping human. Clinically oriented Embryology 10th Edition, Philadelphia,Elsevier Guyton AC, Hall JE (2016) Textbook of medical physiology. 13th Edition, hiladelphia,Elsevier Shier, A., Butler, J., & Lewis, R. (2004). Hole’s Human Anatomy & Physiology.

Standring, S. (2008). Grays’s Anatomy The anatomical basis of clinical practice. United Kingdom: Churchill Livingstone Elservier.

Thibodeau, G. A., & Patton, K. T. (1999). Anatomy & Physiology. Saint Louis: Mosby,

Kumar, A. et al (2004). Robbins Basic Pathology. WB: Saunders.