Chapter 1
THE HUMAN BODY

Introduction
• Anatomy: the study of the structure of the body
• Physiology: the study of the function of the body parts
• Pathology: the study of the disease of the body
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Introduction (cont ’ d.)
• Basic reference systems
– Directions, planes, cavities, structural units
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TERMS OF DIRECTION

Terms of Direction (cont ’ d.)
• Superior: uppermost or above
• Inferior: lowermost or below
• Anterior (or ventral): toward the front
• Posterior (or posterior): toward the back
• Cephalad (or cranial): toward the head
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Terms of Direction (cont ’ d.)
• Medial: nearest the midline of the body
• Lateral: toward the side or away from the midline of the body
• Proximal: nearest the point of attachment or origin
• Distal: away from the point of attachment or origin
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Terms of Direction (cont ’ d.)
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PLANES

Planes (cont ’ d.)
• Midsagittal plane: divides the body through the midline into two equal left and right portions
• Sagittal plane: any plane parallel to the midsagittal or median plan vertically dividing the body into unequal right and left portions
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Planes (cont ’ d.)
• Horizontal (or transverse) plane: any plane dividing the body into superior and inferior portions
• Frontal (or coronal) plane: divides the anterior and posterior portions of the body at right angles to the sagittal plane
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Planes (cont ’ d.)
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Animation – Body Planes
Click Here to Play Body Planes Animation
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CAVITIES

Cavities (cont ’ d.)
• Dorsal
– Cranial, spinal
• Ventral
– Thoracic, abdominopelvic
• Parietal: walls of a cavity
• Visceral: covering on an organ
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Cavities (cont ’ d.)
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STRUCTURAL UNITS

Structural Units (cont ’ d.)
• Cells
– Smallest units of life
– Perform all activities necessary to maintain life
• Metabolism, assimilation, digestion, excretion, reproduction
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Structural Units (cont ’ d.)
• Tissues
– Made up of different types of cells
– Epithelial: covers and protects
– Connective: binds and supports other tissues
– Muscle: movement
– Nervous: connects sensory structures to motor structures
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Structural Units (cont ’ d.)
• Organs
– Cells integrated into tissues
– Serve a common function
– Examples
• Liver
• Stomach
• System is a group of organs
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Structural Units (cont ’ d.)
• Integumentary system
– Organs
• Skin, hair, nails, sweat glands, sebaceous glands
– Functions
• Protection, insulation, regulation of water and temperature
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Structural Units (cont ’ d.)
• Skeletal system
– Organs
• Bones, cartilage, membranous structures
– Functions
• Movement, blood production, fat and mineral storage, protection
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Structural Units (cont ’ d.)
• Muscular system
– Organs
• Muscles, fasciae, tendon sheaths, and bursae
– Functions
• Movement, pushing food and blood, contracting heart
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Structural Units (cont ’ d.)
• Nervous system
– Organs
• Brain, spinal cord, cranial and peripheral nerves, sensory and motor structures
– Function
• Control and regulation, interpreting stimuli
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Structural Units (cont ’ d.)
• Endocrine system
– Organs
• Endocrine glands
– Function
• Works with nervous system to regulate chemical aspects of the body
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Structural Units (cont ’ d.)
• Cardiovascular system
– Organs
• Heart, arteries, veins, capillaries
– Function
• Transport substances to and from cells
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Structural Units (cont ’ d.)
• Lymphatic/immune system
– Organs
• Lymph nodes, lymph vessels, thymus gland, spleen
– Functions
• Drains tissues of excess fluids, transports fats, develops immunities
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Structural Units (cont ’ d.)
• Respiratory system
– Organs
• Nasal cavities, pharynx, larynx, trachea, bronchi, lungs
– Function
• O
2
> CO
2 exchange in the blood
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Structural Units (cont ’ d.)
• Digestive system
– Organs
• Alimentary canal: mouth, esophagus, stomach, small and large intestines, rectum and anus
• Associated glands: salivary, liver, pancreas
– Functions
• Convert food into absorbable substances, eliminates wastes
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Structural Units (cont ’ d.)
• Urinary system
– Organs
• Kidneys, ureters, bladder, urethra
– Functions
• Chemical regulation of blood
• Formation and elimination of urine
• Maintenance of homeostasis
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Structural Units (cont ’ d.)
• Reproductive system
– Organs
• Women: ovaries, uterine tubes, uterus, vagina
• Men: testes, seminal vesicles, prostate gland, penis, urethra
– Functions
• Maintains sexual characteristics and perpetuates the species
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HOMEOSTASIS

Homeostasis (cont ’ d.)
• Maintenance of the body ’ s internal environment
– Within varying narrow limits
• Negative feedback loop
• Examples
– Blood sugar levels
– Body temperature
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Homeostasis (cont ’ d.)
• Blood glucose
– Levels rise dramatically after meal
– Cells take in glucose
– Pancreas secretes insulin
• Moves glucose into liver for storage as glycogen
– Between meals, pancreas secretes glucagon
• Turns glycogen into glucose and returns it to blood
– Thus, glucose levels remain nearly constant
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Homeostasis (cont ’ d.)
• Body temperature
– Hypothalamus detects increase in body temperature
– Causes sweating
• Water evaporates and body is cooled
– Blood vessels dilate to bring blood near body surface
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Homeostasis (cont ’ d.)
• Body monitors deviations in homeostasis
– Negative feedback loop
• Responses that revise disturbances to body ’ s condition
– Positive feedback
• Increase in function in response to stimulus
• Uterine contractions during labor
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Homeostasis (cont ’ d.)
• Organ systems help control internal environment
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Summary
• Discussed the four basic reference systems of body organization (directions, planes, cavities, and structural units)
• Discussed organization of the body into different structural levels (cells, tissues, organs, systems, human organism)
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.

Summary (cont ’ d.)
• Discussed homeostasis and mechanisms for maintaining it
© 2012 Delmar Cengage Learning. All Rights Reserved. May not be scanned, copied, duplicated, or posted to a publicly accessible website, in whole or in part.