Ch01-Organization of the Human Body

Copyright 2010, John Wiley & Sons, Inc.

Chapter 1

Organization of the Human Body


Definitions Anatomy: science that studies structure Physiology: science that studies body functions Anatomy (structure) determines physiology

(functions)


Levels of Organization Chemical: atoms molecules Cellular: cells containing organelles

Basic unit of life Tissue: groups of cells and surrounding material

4 basic types: epithelial, connective, muscular, nervous

Organ: group of tissues performing a common function

System: group of organs with a common function Organism: contains all systems of an individual


Levels of Organization


Life Processes Metabolism- the sum of all the chemical

processes that occur in the body. Responsiveness - the body’s ability to detect

and respond to changes. Movement - includes motion of the whole body,

individual organs, single cells, and even tiny structures inside cells.

Life Processes Growth - is an increase in body size that

results from an increase in the size of existing cells, an increase in the number of cells, or both.

Differentiation - the development of a cell from an unspecialized to a specialized state.

Reproduction - refers either to the formation of new cells for tissue growth, repair, or replacement, or to the production of a

new individual.Copyright 2010, John Wiley &

Sons, Inc.


Autopsy Postmortem examination Examination and dissection of a body to

determine the cause of death when life processes have not been maintained adequately.


Homeostasis is the condition of equilibrium in the body’s

internal environment due to the constant interaction of the body’s many regulatory processes.

Maintaining a stable internal environment Dynamic process because of many changes Examples of variable factors

Body temperature, Blood pressure Water and nutrient levels

Maintained by feedback systems

Feedback sys. or Feedback loop

cycle of events in which the status of a body condition is monitored, evaluated, changed, remonitored, reevaluated, and so on.

monitored variable, such as body temperature, blood pressure, or blood glucose level, is termed a controlled condition.

three basic components of Feedback sys : receptor, control center, and an effector.



Components of Homeostatic Mechanisms Stimulus disrupts a controlled variable Receptor recognizes the change and

sends message = input (typically by nerve pathways) to:

Control Center that evaluates input and sends output to:

Effector that attempts to change the altered variable


Operation of Feedback System


Negative Feedback Systems reverses a change in a controlled condition Most homeostatic control mechanisms are

negative feedback systems “Negative” means “opposite” (not “bad”) These systems reverse a change in the

controlled variable, bringing it back to “normal” Example: high blood pressure (BP) is detected

and then lowered to normal BP


Negative Feedback Systems


Positive Feedback Systems Few homeostatic control mechanisms are of

this type These systems strengthen a change and

must be shut down by an outside force. Examples:

Contractions of uterus cause even more contractions at child birth

Hormonal control of ovulation Systems that control blood clotting


Clinical Terms

Disorder: abnormality of structure/function Disease: specific illness characterized by signs

and symptoms Symptoms: subjective changes not observable from

outside a person. Examples: pain, headache, nausea, anxiety

Signs: observable or measurable changes. Examples: can be either anatomical, such as swelling or a rash, or physiological,such as fever, high blood pressure, or paralysis.


Aging and Homeostasis

Normal process that: Includes a progressive loss in the ability to

maintain homeostasis (homeostatic imbalance) Affects all body systems Can be slowed down or minimized by healthy

living


Anatomical Terms Precise use of language to define position,

direction, and location in the body. Anatomical position

Stands erect facing the observer, with head level and eyes facing forward, and palms facing forward

Common and anatomical terms Directional terms Planes and sections Body cavities


Anatomical Position

Directional Terms

Superior - toward the head Inferior - away from the head Anterior (ventral) - nearer to or at the front of the

body Posterior (dorsal) - nearer to or at the back of the

body Medial – nearer to the midline Lateral- farther from the midline Intermediate – between two structures


• words that describe the position of one body part relative to another

Directional Terms Ipsilateral -On the same side of the body as

another structure Contralateral - On the opposite side of the body

from another structure Proximal - Nearer to the attachment of a limb to the

trunk; nearer to the origination of a structure Distal - Farther from the attachment of a limb to the

trunk; farther from the origination of a structure Superficial (external)-Toward or on the surface of

the body Deep (internal)- Away from the surface of the body.



Directional Terms

Planes Through the Human Body Planes - imaginary flat surfaces that pass through the body parts Sagittal plane - a vertical plane that divides the

body or an organ into right and left sides. midsagittal plane or a median plane - a plane

passes through the midline of the body or an organ and divides it into equal right and left sides

parasagittal plane - divides the body or an organ into unequal right and left sides

frontal or coronal - divides the body or an organ into anterior (front) and posterior (back) portions.


Planes Through the Human Body

Transverse plane - divides the body or an organ into superior and inferior portions.

aka cross-sectional or horizontal plane

Oblique plane - passes through the body or an organ at an oblique angle.



Planes Through the Human Body


Planes and Sections: Brain•Section - is a cut of the body or one of its organs made along one of the planes


Planes and Sections: Brain

Anatomical Terms

Body cavities - are spaces within the body that help protect, separate, and support internal organs.



Anatomical Terms Body cavities

Cranial (brain) and vertebral (spinal cord) Thoracic (chest cavity): pleural, pericardial, and

mediastinal (region between lungs) Abdominopelvic (inferior to diaphragm):

Abdominal Larger; contains most abdominopelvic organs Subdivided into 9 regions or 4 quadrants

Pelvic More inferior and smaller Contains urinary bladder, lowest portions of digestive

tract, and internal reproductive organs


Anatomical Terms Body cavities

Serous membranes are located in thoracic and abdominopelvic cavities

Functions: protect organs, reduce friction Layers

Visceral layer covers organs Parietal layer lines cavity

Names: Pleural (covers lungs, lines thorax) Pericardial (covers heart, lines central part of thorax) Peritoneal (covers organs, lines abdominopelvic cavity)


Body Cavities

Anterior view of thoracic cavity


Anterior View of Abdominopelvic cavity



Abdominopelvic Cavity: 9 Regions


Abdominopelvic Cavity: 4 Quadrants

Other body cavities Oral (mouth) cavity, which contains the tongue

and teeth Nasal cavity in the nose Orbital cavities (orbits), which contain the

eyeballs Middle ear cavities which contain small bones Synovial cavities which are found in freely

movable joints and contain synovial fluid


References

Tortora, G.J., & Derrickson, B. (2012). Principles of ANATOMY & PHYSIOLOGY. (13th ed.). John Wiley & Sons, Inc., Hoboken (NJ)

Tortora, G.J., & Derrickson, B. (2009). Principles of ANATOMY & PHYSIOLOGY. (12th ed.). John Wiley & Sons, Inc., Hoboken (NJ)


End of Chapter 1 Copyright 2010 John Wiley & Sons, Inc.

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Ch01-Organization of the Human Body

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