1. An Introduction to the Structure and Function of the Body
Chapter 1
An Introduction to the Structure and Function of the Body

2. Objectives Define anatomy and physiology.
Describe the process used to form scientific theories.
List and discuss in order of increasing complexity the levels of organization of the body.
Pages 3-6

3. Anatomy & Physiology
Anatomy – study of the structure of an organism and the relationship of its parts
* Anatomists learn about the body by dissection
Physiology – the study of the functions of living organisms and their parts
* Physiologists use scientific experimentation

4. Levels of Study Gross Anatomy Microscopic Anatomy Large structures
Easily observable
Microscopic Anatomy
Very small structures
Can only be seen with a microscope 4

5. Scientific Method
No single approach but many scientists follow these steps.
The process of science is active
and changing as
new experiments
add new knowledge.

6. Key Terms Hypothesis – reasonable guess based on previous
observations or experiments
Experiment – series of tests of a hypothesis; should
be as simple as possible to avoid errors
Experimental controls are used to ensure that the test situation is not affecting the results
Control group receives no treatment
Treatment group receives treatment or intervention
Theory or law – a hypothesis that has gained a high
degree of confidence 6

7. Flashcards series of tests of a hypothesis that eliminates biases or
outside influences
Experiment
idea or principle to be tested in experiments
Hypothesis
receives no treatment
Control Group
a hypothesis that has been proven to have a high degree of
confidence
Theory or law 7

8. Levels of Organization

9. Levels of Organization
Cell –the small structural “living” units of structure and
function in the body
Tissue – organization of similar cells that act together to
perform a common function ( epithelium, muscle, nervous,
etc.)
Organ – tissues that act as a unit to perform a specific
function (skin, femur, heart, kidney, etc.)
Organ System – organs working together to perform
complex functions (skeletal system, digestive system, etc.)
Organism – the human being

10. Flashcards
small structural “living” units of structure and function in the body
Cell
Organ
tissues that act as a unit to perform a specific
function
Organism
the human being
organs working together to perform
complex functions
Organ System
organization of similar cells that act together to
perform a common function
Tissue 10

11. Quick Check
What is the difference between anatomy, physiology and pathology?
What are the major levels of organization in the body?
How is tissue different than an organ?

12. Objectives 4 - 8 Define anatomical position, supine and prone.
List and define the principal directional terms and sections (planes) used in describing the body and the relationship of body parts to one another.
List the major cavities of the body and the subdivisions of each.
List the nine abdominopelvic regions and the abdominopelvic quadrants.
Discuss and contrast the axial and the appendicular subdivisions of the body and identify anatomical regions in each area.

13. Anatomical Position
Anatomical Position – a point of reference with the body standing erect, facing forward, upper limbs at the sides, palms facing forward and thumbs out
The body has bilateral symmetry.
Supine and prone are terms to describe the position of the body when it is not in anatomical position.

14. Flashcards Standing erect, arms by the side with palms forward
Laying face up or “on the spine”
Supine
Standing erect, arms by the side with palms forward
Anatomical position
Laying face down or “posterior up”
Prone 14

15. Anatomical Directions
Superior / Inferior
(Cranial vs. Caudal)
Anterior / Posterior
(Ventral vs. Dorsal)
Medial / Lateral
Proximal / Distal
Superficial / Deep
Internal / External

16. Flashcards - Directions
Toward the side of the body or away from the midline
Lateral
Toward the midline of the body
Medial
Front, in front of
Anterior
Superior
Toward the head, upper or above
Back, in back of
Posterior
Toward the feet, lower or below
Inferior 16

17. Flashcards - Directions
Proximal
Toward or nearest the trunk or point of origin
Away from or farthest from the trunk or point of origin
Distal
Superficial
Nearer the body surface
Farther away from the body surface
Deep 17

19. Planes of the Body
Sagittal or Medial – divides body into left and right
portions
Mid-sagittal – divides body into equal left and right
Transverse or Horizontal – divides body into superior
and inferior portions
Coronal or Frontal – divides body into anterior and
posterior portions

20. Transverse Section

21. Flashcards - Planes Divides the body into upper and lower sections
Frontal or Coronal
Divides the body into anterior and posterior sections
Divides the body into upper and lower sections
Tranverse
Sagittal
Divides the body into right and left sections
Divides the body into two equal halves
Midsagittal 21

22. Body Cavities

23. Abdominal Quadrants

24. Abdominal Regions

25. Body Regions

26. Axial & Appendicular Divisions

27. Quick Check Name and describe the planes of the body.
Describe anatomical position.
List and describe the body cavities.
Describe the abdominal quadrants.
Name the nine abdominal regions.
List 4 body regions and describe the location.
What is the difference between the axial and appendicular divisions?

28. Objectives
9. Explain the meaning of the term homeostasis and give an example of a homeostatic mechanism.

29. The Balance of Body Functions
Copyright © 2016 by Elsevier Inc. All rights reserved.
The Balance of Body Functions
Survival depends on the body maintaining relatively constant conditions
Body mechanisms act as heaters, air pumps, and the like, to maintain the relatively stable conditions
Although they may have very different structures, all living organisms maintain mechanisms that ensure survival of the body and success in propagating its genes through its offspring.
What is homeostasis? (Homeostasis is what physiologists call the relative constancy of the internal environment.)

30. The Body’s Internal Environment
Figure 1-10 shows a diagram of the body’s internal environment.
The human body is like a bag of fluid separated from the external environment.
Tubes, such as the digestive tract and respiratory tract, bring the external environment to deeper parts of the bag where substances can be absorbed into the internal fluid environment or excreted into the external environment.

31. Feedback Control Feedback loop: Body’s general control system.
Feedback Control
Feedback loop: Body’s general control system
Nerve endings feed information to a control center in the brain that compares actual temp to the normal temp
Negative feedback: Opposes change in controlled condition
Positive feedback: Amplifies occurring change
The idea of a feedback loop is borrowed from engineering.
Shivering produces heat that increases our body temperature.
Most homeostatic control loops in the body involve negative feedback because reversing changes back toward a normal value tends to stabilize conditions.
A positive feedback loop feedback loop causes an ever-increasing rate of events to occur until something stops the process.

32. Copyright © 2016 by Elsevier Inc. All rights reserved.
Negative Feedback
Figure 1-11, A, is an engineer’s diagram showing how a relatively constant room temperature (controlled condition) can be maintained.
Figure 1-11, B, is a physiologist’s diagram illustrating how a relatively constant body temperature (controlled condition) can be maintained.

33. Positive Feedback Loop
Copyright © 2016 by Elsevier Inc. All rights reserved.
Positive Feedback Loop
Figure 1-12 is an example of positive feedback that occurs when a baby is born.
As the baby is pushed from the womb (uterus) into the birth canal (vagina), stretch receptors detect the movement of the baby. Stretch information is fed back to the brain, triggering the pituitary gland to secrete a hormone called oxytocin (OT).
OT travels through the bloodstream to the uterus, where it stimulates stronger contractions.
Stronger contractions push the baby farther along the birth canal, thereby increasing stretch and stimulating the release of more OT.

34. Copyright © 2016 by Elsevier Inc. All rights reserved.
Normal Fluctuations
Homeostatically controlled conditions don’t remain absolutely constant
Conditions fluctuate near an ideal value
Ability to maintain balance is related to age
Developmental processes
Aging processes
Thus body temperature, for example, rarely remains exactly the same for very long.
It usually fluctuates up and down near a person’s normal body temperature.
Changes and functions occurring during the early years are called developmental processes.
Those occurring after young adulthood are called aging processes.

35. Quick Check
Why is homeostasis also called the “balance” of body function?
What is a feedback loop and how does it work?
How does negative feedback differ from positive feedback?