Human Body: An Orientation Anatomy & Physiology Chapter 1.

Human Body: Human Body: An An OrientationOrientation

Anatomy & PhysiologyChapter 1

Life FunctionsLife Functions

Maintaining Life Necessary Life Functions

Maintain boundaries Move Respond to environmental changes Take in and digest nutrients Carry out metabolism Dispose of waste Reproduce themselves Grow


Maintain boundariesMaintain boundaries – an organism internal environment must remain distinct from the external environment

Movement Movement – all activities promoted by the muscular system

ResponsivenessResponsiveness – the ability to sense changes in the environment and then respond to them

DigestionDigestion – process of breaking down ingested foodstuffs to simple molecules that can be absorbed into the blood


MetabolismMetabolism – all chemical reactions that occur within the body cells

ExcretionExcretion – process of removing wastes from the body

ReproductionReproduction – Cellular Level: original cell divides producing 2

identical daughter cells that can be used for body growth or repair

Organismal Level: when sperm and egg unite producing a fertilized egg which develops into a fetus within the mother’s body

GrowthGrowth – increase in size of a body part or the organism Increase the number of cells

Survival NeedsSurvival Needs

Survival Needs Nutrients Oxygen Water

60 – 80% of body weight

Appropriate Temperature Atmospheric Pressure

Homeostasis Homeostasis – dynamic state of equilibrium or balance Internal conditions vary but within narrow limits Variable – factor or event being regulated

Divisions of AnatomyDivisions of Anatomy

RegionalRegional – all structures are in a particular region of the body

SystemicSystemic– gross anatomy of the body studied system by system

MicroscopicMicroscopic– thin slices of body tissues are examined under the microscope

PathologicalPathological– studies structural changes caused by disease

Homeostatic ControlHomeostatic Control

Homeostatic Control MechanismsHomeostatic Control Mechanisms – have at least 3 interdependent components

1. Receptor – some type of sensor that monitors the environment and responds to changes (stimuli) by sending information to the central center

2. Control Center – determines the set point at which a variable is to be maintained, analyzes the input it receives, and determines the appropriate response

3. Effector – provides the means for the central center’s response to the stimulus


Negative Feedback Mechanisms

The goal is to prevent sudden, severe changes within

the body

Maintaining blood glucose levels

Regulation of body temperature by nervous system

Examples: regulate heartbeat, rate and depth of breath,

and blood levels of oxygen, carbon dioxide, and minerals


Positive Feedback Mechanisms:

Response enhances the original stimulus

Change that occurs proceeds in the same direction as the initial disturbance

Control infrequent events that do not require continuous adjustments

Examples: blood clotting, contractions during the birth of a baby

Homeostatic ImbalanceHomeostatic Imbalance: disruption of homeostasis causing disease

Language of AnatomyLanguage of Anatomy

1. Anatomical Position and Directional Termsa.a. Anatomical PositionAnatomical Position: reference point used to

describe body parts and position accurately (Standard body position)1. Human body erect2. Arms at side3. Palms forward, thumbs pointed away from

the body4. Feet together* Right and Left – refers to the sides of the

person being viewed not those of the observer!


Anatomical Position


2.2. Directional TermsDirectional Terms – explains where one body structure is in relation to another

a. Superior: toward the head end or upper part; aboveInferior: away from head end or toward the lower part, below

b. Anterior: toward the front of the bodyPosterior: toward the back of the body


c. Medial: toward or at the midline of the bodyLateral: away from the midline of the bodyIntermediate: between a more medial and more lateral structure

d. Proximal: closer to the origin of the body part or the point of attachment of a limb to the body trunk

Distal: farther from the origin of a body part or the point of attachment of a limb to the body trunk

e. Superficial: toward or at the body surface

Deep: away from the body surface


3.3. Regional TermsRegional Terms – used to designate specific areas within the major body divisions

a. Major Body Divisions1. Axial – main axis of our body (i.e. head, neck, trunk)2. Appendicular – consists of appendages or limbs

4. Body Planes and Sectionsa.a. PlanesPlanes – cut along a flat surface

1. Sagittal: vertical plane that divides the body into right and left partsMedian/Midsagittal: sagittal plan that lies exactly in the midlineParasagittal: offset from the midline


2. Frontal/Coronal: divide the body into anterior and posterior parts

3. Transverse/Horizontal: runs horizontally from right to left, divides the body into superior and inferior parts

- Also called a cross section

4. Oblique: cuts made diagonally between the horizontal and the vertical planes


5. Body Cavities and Membranesa.a. Dorsal Body CavityDorsal Body Cavity: protects the nervous

system organs1. Cranial Cavity – encases the brain2. Vertebral Cavity – encases the delicate spinal

column

b.b. Ventral Body CavityVentral Body Cavity : anterior1. Thoracic – Superior division, surrounded by the ribs

and muscles of the chesta. Pleural Cavity: houses a lungb. Mediastinum: contains the pericardial cavity

which encloses the heart, surrounds the esophagus, and trachea

- separates the lungs into right and left cavities


c. Abdominopelvic Cavity:1. Abdominal Cavity – contains the stomach,

intestines, spleen, liver2. Pelvic Cavity – lies within the bony pelvis,

contains the bladder, reproductive organs, and rectum

d. Visceral Organs: group of internal organs collectively called viscera

e. Diaphragm – dome shaped muscle important in breathing. Separates the thoracic and abdominopelvic cavities.


Abdominopelvic Cavity QuadrantsBecause the abdominopelvic cavity is

quite large, it is often divided into four or more equal regions called quadrants

The Four Most Common Quadrants Are: Right Upper Quadrant Right Lower Quadrant Left Upper Quadrant Left Lower Quadrant

Human Body: An Orientation Anatomy & Physiology Chapter 1.

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