Chapter 1 · 2012. 3. 7. · Chapter 1: An Introduction to the Human Body Six levels of structural organization 1. Chemical level (atoms to molecules) 2. Cellular level (molecules

Chapter 1

An Introduction to the

Human Body

Chapter 1: An Introduction to the Human

Body

Six levels of structural organization

1. Chemical level (atoms to molecules)

2. Cellular level (molecules are organized into cells)

3. Tissue level (groups of similar cells work together)

4. Organ level (two or more tissues become an organ)

5. System level (related organs with common functions)

6. Organismal level (all of the cells, tissues, and organ systems

become a human being)

The Six Levels of Structural Organization

Integumentary System

Skeletal System

Muscular System

Nervous System

Endocrine System

Cardiovascular System

Lymphatic System and Immunity

Respiratory System

Copyright 2010, John Wiley & Sons, Inc.

Digestive System


Urinary System


Reproductive Systems

Copyright 2010, John Wiley & Sons, Inc. Copyright 2009, John Wiley & Sons, Inc.

Basic Processes of Living Systems

Life differs from nonliving matter in these ways:

Metabolism - all of the chemical processes of life

Responsiveness - living systems detect and

respond to changes in their environments

Movement - cells, organs, and/or bodies move

Growth - cells, organs, and bodies all grow

Differentiation - the process of cellular specialization

Reproduction - both cells and organisms make copies of

themselves


Homeostasis — A Fundamental Pattern

Found in All Living Systems

Homeostasis is the maintenance of relatively constant

conditions inside the body

First described by Claude Bernard in 1865, the term was coined

by Walter Cannon in the early 1900’s

Although conditions within the body are stable, this is a result of

many dynamic processes that constantly adjust internal activities

to match changing needs

Some examples of stable conditions are blood glucose, body

temperature, and blood pressure


Homeostasis Interactions Animation

Communication, Regulation and

Homeostasis

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Body Fluids - A Key Focus for Homeostasis

The volume and composition of the various fluids

within our bodies are carefully regulated

Our body fluids include:

Intracellular fluid - the fluid inside our cells

Extracellular fluid – all body fluids other than the ones inside our

cells. Can be subdivided according to location:

Interstitial fluid - the fluid between cells in tissues

Plasma - the fluid component of blood

Lymph - the fluid in our lymphatic vessels

Cerebrospinal Fluid (CSF) - the fluid within the CNS

Synovial fluid - the fluid within most joints


Homeostasis - Restoring “Balance” to the Body

Feedback systems control our internal environment

Negative feedback systems act to stabilize the body in the face of

changing external and internal conditions. These systems cause

an opposite response to the initial change, and so are self-

limiting.

Positive feedback systems are important in specific situations,

when a very rapid or very strong effect is desired. Unlike negative

feedback, here the response is the same as that caused by the

initial change.

An outside event must break the positive feedback cycle.


Negative Feedback Systems

Three essential components

receptor - detects changes in controlled conditions

control center - decides the type and amount of response

required

effector - reacts to signals from the control center and

produces the required response

The term “negative feedback” is used because the

response is opposite in direction to the original change


Operation of a

Feedback System


Negative Feedback – Temperature Interactions Animation

Negative Feedback Control of Temperature


http://www.wiley.com/college/jenkins/0470227583/animations/index_01_03_03.html


Blood Pressure Regulation:

Homeostatic Regulation by Negative

Feedback Three essential components

baroreceptors - detect changes in blood pressure and

communicate with the brain

the brain - interprets information and sends signals to the heart

and blood vessels

heart and blood vessels - alter their activities based on signals

from the brain

Resulting in the blood pressure being restored to

normal


Blood Pressure

Regulation


Blood Pressure Regulation Interactions Animation

Negative Feedback Control of Blood

Pressure


http://www.wiley.com/college/jenkins/0470227583/animations/index_01_03_02.htmlhttp://www.wiley.com/college/jenkins/0470227583/animations/index_01_03_02.html


Positive Feedback

A stimulus causes a response that reinforces the effect of

the stimulus

A positive feedback cycle must be stopped or limited by

some event or condition outside of the cycle


Positive Feedback

Control of Labor


Positive Feedback – Labor Interactions Animation

Positive Feedback Control of Labor


http://www.wiley.com/college/jenkins/0470227583/animations/index_01_03_04.html


Describing the Human Body

A set of standard terms is used to make descriptions of

the body more easily understood

Anatomical position - a reference position for the body

Body regions - a set of terms for body regions derived from Latin

and Greek are commonly used in Anatomy and Medicine

Directional terms - these terms describe locations (on or within

the body) relative to one another

Planes and sections - these terms help to describe internal

locations within the body or within an organ along defined cuts.

Body cavities - internal spaces within the body where many

organs are found, and where much of physiology happens


Anatomical Position - The Standard Reference

Position for All of Anatomy


Directional Terms


Planes and Sections of the Body

A way to describe internal body locations

Sagittal plane

Midsagittal (or medial) plane

Parasagittal planes

Frontal (or coronal) plane

Transverse plane

A section is a view of the body cut along one of the

specific planes


Planes and Sections of the Brain

The complexity of the brain shows the usefulness of planes and sections


Body Cavities

Major internal body spaces

Cranial cavity

Vertebral cavity

Thoracic cavity

Abdominopelvic cavity

Abdominal cavity

Pelvic cavity


Body Cavities


Serous Membranes

Double-walled tissue membranes surround many

internal organs and line the body cavities in which

the organs are located.

Major examples include:

Pleura

Pericardium

Peritoneum


Serous Membranes


Two Different Systems Exist for Describing

Locations within the Abdominopelvic Cavity

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Chapter 1 · 2012. 3. 7. · Chapter 1: An Introduction to the Human Body Six levels of structural organization 1. Chemical level (atoms to molecules) 2. Cellular level (molecules