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 bodycovering

– Protects deeper tissue frominjury

– Synthesizes vitamin D– Location of cutaneous

nerve receptors

Figure 1.2b

Organ System Overview• Skeletal

– Protects and supportsbody organs

– Provides muscleattachment for movement

– Site of blood cellformation

– 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

• http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000070&ptid=17

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