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Chapter 1

The Human Organism•The body is truly more than the sum of its parts and understanding the connectedness of the human structure and function is the real challenge. Homeostasis is the “glue” and basis which explains this relationship.

•Realize Anatomy and Physiology is a language. Study it like a language.

Welcome to YOUR nursing career!

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Overview of Anatomy and Physiology

• Anatomy: scientific discipline that investigates the body’s structure

• Physiology: scientific investigation of the processes or functions of living things

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Topics of Anatomy

• Gross or macroscopic: structures examined without a microscope– Regional: studied area by area– Systemic: studied system by system– Surface: external form and relation to deeper

structures as x-ray in anatomic imaging

• Microscopic: structures seen with the microscope– Cytology: cellular anatomy– Histology: study of tissues

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Topics of Physiology

• Reveals dynamic nature of living things

• Considers operations of specific organ systems– Cell physiology: examines processes in cells– Neurophysiology: focuses on the nervous

system– Cardiovascular: the heart and blood vessels

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Subjects That Encompass Both Anatomy and Physiology

• Pathology: structural and functional changes caused by disease

• Exercise Physiology: changes in structure and function caused by exercise

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Structural & Functional Organizations

• Chemical Level: interaction of atoms

• Cell Level: functional unit of life

• Tissue Level: group of similar cells and the materials surrounding them

• Organ Level: one or more tissues functioning together

• Organ System Level: group of organs functioning together

• Organism Level: any living thing.

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Homeostasis

• Homeostasis—maintenance of a stable internal environment – A dynamic state of equilibrium

• Homeostasis is necessary for normal body functioning and to sustain life

• Homeostatic imbalance– A disturbance in homeostasis resulting in

disease

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Homeostasis

• Values of variables fluctuatearound the set point to establish a normal range of values.

• Set point: the ideal normal value of a variable.

• What is the set point for body temperature?

Homeostatic Control Mechanisms

• Process for maintaining homeostasis

• How does the body maintain proper Oxygen levels during exercise?

Maintaining Homeostasis

• The body communicates through neural and hormonal control systems

• Receptor• Responds to changes in the environment (stimuli)

• Sends information to control center

• Afferent pathway

Maintaining Homeostasis

– Control center• Determines set point

• Analyzes information

• Determines appropriate response

– Effector• Provides a means for response to the stimulus

• Efferent pathway

Feedback Mechanisms

• Negative feedback– Includes most homeostatic control mechanisms– Decreases the original stimulus, or reduces its

intensity– inhibitory– Works like a household thermostat

Feedback Mechanisms

• Positive feedback– Increases the original stimulus to push the variable

farther– In the body this only occurs in blood clotting and

during the birth of a baby– Stimulatory

Feed-forward control systems occur when information flows ahead to another process or feedback loop to trigger a change in anticipation of an event that will follow

Feedback Systems Summary

• Two types: negative and positive• It is important to note that in science, negative means “to take

away” while positive means “to gain”• Components

– Receptor: monitors the value of some variable– Control center: establishes the set point– Effector: can change the value of the variable

• Stimulus: deviation from the set point; detected by the receptor• Response: produced by the effector

• Be able to give examples of BOTH – (hint: what is the rule? and the few exceptions)

Levels of Homeostatic Control– Intracellular control

• Regulation within cells• Genes or enzymes can regulate cell Processes

– Intrinsic control (autoregulation)• Regulation within tissues or organs• May involve chemical signals• May involve other “built in” mechanisms

– Extrinsic control• Regulation from organ to organ• May involve nerve signals• May involve endocrine signals (hormones)

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Terminology and Body Plan• Anatomical Position

– Body erect, face forward, feet together, palms face forward

• Other Body Positions– Supine: lying face upward– Prone: lying face downward

• Directional Terms– Superior (Cephalic) vs. Inferior

(Caudal) toward or away from the head– Medial vs. Lateral relative to the

midline– Proximal vs. Distal used to describe

linear structures– Superficial vs. Deep relative to the

surface of the body– Ipsilateral vs. Contralateral same or

opposite side of the body

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Terminology and Body Plan (cont.)

• Directional Terms (cont.)– Anterior (Ventral) vs.

Posterior (Dorsal). Anterior is forward; posterior is toward the back.

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Intra: inside

Inter: between

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Body shapes and Disease - How structure and function are

interrelated

-Three body types: 1. Endomorph 2. Mesomorph 3. Ectomorph

- Apple shaped are at a higher risk of heart disease, stroke, high blood pressure and diabetes than those who carry their weight around the hips and thighs

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Body Parts and Regions

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Body Parts and Regions

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Abdominal Subdivisions

Regions Quadrants

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Planes of Section Through an Organ

• Longitudinal: cut along the length of an organ

• Cross/Transverse: cut at right angle to length of the organ

• Oblique: cut at any but a right angle

Terms Related to Organs

– Lumen (luminal)hollow area within and organ

– Central and peripheral near the center v near the boundary

– Medullary (medulla) and cortical (cortex) inner region v outer region

– Apical (apex) and basal (base) narrow tip v widest area of an organ

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Body Planes• Median (through

the midline) and Sagittal (same plane, but to the left or right of median

• Frontal or Coronal divides body into anterior and posterior sections

• Transverse / Cross divides body into superior and inferior sections

• Oblique: Other than at a right angle

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Body Cavities

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Trunk Cavities • Diaphragm: divides body cavity into thoracic and abdominopelvic cavities.

• Mediastinum: contains all structures of the thoracic cavity except the lungs

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Serous Membranes• Cover the organs of trunk

cavities & line the cavity

• Fist represents an organ

• Inner balloon wall represents visceral serous membrane

• Outer balloon wall represents parietal serous membrane

• Cavity between two membranes filled with lubricating serous fluid that is produced by the membranes

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Serous Membranes: Named for Their Specific Cavities and Organs

– Pericardium refers to heart. – Pleura refers to lungs and thoracic cavity– Peritoneum refers to abdominopelvic cavity

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Review

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Also…

• Mechanisms of Disease.– pp.25-28 including Disease

terminology in “Health Matters”

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What kind of feed back is this?

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What plane is this?