Chapter 1 The Human Body

2 Introduction Anatomy - the study of the structure of the body Physiology - the study of the function of the body parts Basic reference systems –directions, planes, cavities, structural units

3 Terms of Direction

Orientation and Directional Terms Table 1.1

Orientation and Directional Terms Table 1.1 (cont)

6 Planes

7 Cavities Dorsal –cranial, spinal Ventral –thoracic, abdominopelvic

Body Cavities Figure 1.7

Abdominopelvic Quadrants Figure 1.8a

Abdominopelvic Regions Figure 1.8b

Body Planes Figure 1.6

Body Landmarks Anterior Figure 1.5a

Body Landmarks Posterior Figure 1.5b

Structural Units

15 Cells Smallest units of life Perform all activities necessary to maintain life –metabolism, assimilation, digestion, excretion, reproduction

16 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

17 Organs Cells integrated into tissues Serve a common function Examples –liver –stomach

Systems A group of organs that perform a common function

Figure 1.2a Organ System Overview Integumentary –Forms the external body covering –Protects deeper tissue from injury –Synthesizes vitamin D –Location of cutaneous nerve receptors

Figure 1.2b Organ System Overview Skeletal –Protects and supports body organs –Provides muscle attachment for movement –Site of blood cell formation –Stores mineral

Figure 1.2c Organ System Overview Muscular –Allows locomotion –Maintains posture –Produces heat

Figure 1.2d Organ System Overview Nervous –Fast-acting control system –Responds to internal and external change –Activates muscles and glands

Figure 1.2e Organ System Overview Endocrine –Secretes regulatory hormones Growth Reproduction Metabolism

Figure 1.2f Organ System Overview Cardiovascular –Transports materials in body via blood pumped by heart Oxygen Carbon dioxide Nutrients Wastes

Organ System Overview Lymphatic –Returns fluids to blood vessels –Disposes of debris –Involved in immunity Figure 1.2g

Organ System Overview Respiratory –Keeps blood supplied with oxygen –Removes carbon dioxide Figure 1.2h

Organ System Overview Digestive –Breaks down food –Allows for nutrient absorption into blood –Eliminates indigestible material Figure 1.2i

Organ System Overview Urinary –Eliminates nitrogenous wastes –Maintains acid – base balance –Regulates water and electrolytes Figure 1.2j

Organ System Overview Reproductive –Production of offspring Figure 1.2k

30 Homeostasis Maintenance of the body’s internal environment Negative feedback loop Examples –blood sugar levels –body temperature

Homeostasis Maintenance of a stable internal environment = a dynamic state of equilibrium Homeostasis must be maintained for normal body functioning and to sustain life Homeostatic imbalance – a disturbance in homeostasis resulting in disease

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Overview of Homeostasis Figure 1.4

Maintaining Homeostasis The body communicates through neural and hormonal control systems –Receptor Responds to changes in the environment (stimuli) Sends information to control center

Maintaining Homeostasis –Control center Determines set point Analyzes information Determines appropriate response –Effector Provides a means for response to the stimulus

Feedback Mechanisms Negative feedback –Includes most homeostatic control mechanisms –Shuts off the original stimulus, or reduces its intensity –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 birth of a baby