1. Ch. 1 The Human Body: An Orientation

2. What is Anatomy and Physiology?
Anatomy is the study of the structure & parts of the body
Physiology is the study of function at many levels
Function always reflects structure
What a structure can do depends on its specific form

3. Levels of Structural Organization
Chemical level: atoms and molecules
Cellular level: cells and their organelles
Tissue level: groups of similar cells
Organ level: contains two or more types of tissues
Organ system level: organs that work closely together
Organismal level: all organ systems

4. Levels of Structural Organization
Smooth muscle cell
Atoms 1
Chemical level
Molecules
Atoms combine to
form molecules. 2
Cellular level
Cells are made up of molecules.
Smooth
muscle
tissue 3
Tissue level
Blood
vessels
Tissues consist of
similar types of cells.
Heart
Epithelial
tissue
Smooth
muscle
tissue
Blood
vessel
(organ)
Cardio–
vascular
system
Connective
tissue 4
Organ level
Organs are made up of different types of tissues. 5
Organ system level 6
Organismal level
Organ systems consist of
different organs that work
together closely.
Human organisms are
made up of many organ
systems.

5. Survival Needs of Living Organisms
Nutrients
Chemicals for energy and cell building
Carbohydrates, fats, proteins, minerals, vitamins, water
Oxygen
Essential for energy release (ATP production)

6. Survival Needs of Living Organisms
Water
Most abundant chemical in the body
Site of chemical reactions
Normal body temperature
Affects rate of chemical reactions
Appropriate atmospheric pressure
For adequate breathing and gas exchange in the lungs

7. Living Organisms Must Maintain Homeostasis
Homeostasis is the maintenance of a relatively stable internal environment despite continuous outside changes
Homeostatic control mechanisms are responsible for maintaining homeostasis

8. The Elements of a Homeostatic Control System3
Output: Information
is sent along efferent
pathway to effector. 4
Input: Information
is sent along afferent
pathway to control
center.
Control
Center
Afferent
pathway
Efferent
pathway
Receptor
Effector
Receptor
detects change. 2 5
Response
of effector feeds
back to reduce
the effect of
stimulus and
returns variable
to homeostatic level. 1
Stimulus
produces
change in
variable.
IMBALANCE
VARIABLE (in homeostasis)
IMBALANCE

9. Components of a Homeostatic Control Mechanism
Receptor (sensor)
monitors the environment
senses stimuli in the environment
Control Center
receives input from the receptor
determines the set point at which a variable is maintained
determines the appropriate response

10. Components of a Control Mechanism
Effector
receives output from control center
provides the means to respond
response acts to reduce or enhance the original stimulus (feedback)

11. Negative Feedback
When the response reduces or shuts off the original stimulus this is negative feedback
Example:
Regulation of body temperature

12. Temperature-sensitive Temperature-sensitive
Control Center
(thermoregulatory
center in brain)
Information sent
along the afferent
pathway to control
center
Information sent
along the efferent
pathway to
effectors
Afferent
pathway
Efferent
pathway
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Sweat glands
Sweat glands activated
Response
Evaporation of sweat
Body temperature falls;
stimulus ends
Stimulus
Body temperature
rises
BALANCE
Stimulus
Body temperature falls
Response
Body temperature rises;
stimulus ends
Receptors
Temperature-sensitive
cells in skin and brain
Effectors
Skeletal muscles
Efferent
pathway
Afferent
pathway
Shivering
begins
Information sent
along the efferent
pathway to effectors
Information sent
along the afferent
pathway to control
center
Control Center
(thermoregulatory
center in brain)
Figure 1.5

13. Rare in biological systems Example:
Positive Feedback
When the response enhances or exaggerates the original stimulus this is positive feedback
Rare in biological systems
Example:
Enhancement of labor contractions by oxytocin

14. The Anatomical Position is used as a frame of reference
Body erect
Feet slightly apart
Palms facing forward

15. Table 1.1

16. Table 1.1

17. Table 1.1

18. Table 1.1

19. Table 1.1

20. Regional Terms
Regional Terms: Specify specific areas on the body

21. Upper limb Acromial Orbital Brachial (arm) Nasal Antecubital Oral
Antebrachial
(forearm)
Cervical
Carpal (wrist)
Thoracic
Axillary
Digital
Sternal
Abdominal
Lower limb
Umbilical
Coxal (hip)
Pelvic
Femoral (thigh)
Inguinal
Patellar
Crural (leg)
Pubic
Fibular
Tarsal (ankle)
Thorax
Abdomen
Back (Dorsum)
(a) Anterior/Ventral
Figure 1.5

22. Upper limb Cephalic Acromial Brachial (arm) Occipital Olecranal
Cervical
Back (dorsal)
Scapular
Vertebral
Digital
Lumbar
Sacral
Femoral (thigh)
Gluteal
Popliteal
Sural (calf)
Fibular
Calcaneal
Plantar
(b) Posterior/Dorsal
Figure 1.5

23. Body Planes and Sections
There are Three Anatomical Planes: Sagittal, Frontal, Transverse
1) Sagittal plane
Divides body vertically into right and left parts
Produces a sagittal section
1a) Midsagittal (median) plane
Lies on midline
1b) Parasagittal plane
Not on midline

24. Frontal (coronal) plane
Body Planes
Frontal (coronal) plane
Divides body vertically into anterior and posterior parts
Transverse (horizontal) plane
Divides body horizontally into superior and inferior parts
Produces a cross section

25. Median (midsagittal) plane
Frontal plane
Median (midsagittal) plane
Transverse plane
(a) Frontal section
(through torso)
(b) Transverse section
(through torso,
inferior view)
(c) Median section
(midsagittal)
Pancreas
Aorta
Spleen
Left and
right lungs
Liver
Heart
Spleen
Liver
Spinal cord
Rectum
Intestines
Body wall
Stomach
Arm
Vertebral
column
Subcutaneous fat layer
Figure 1.6

26. There are Two Large Body Cavities: Dorsal and Ventral
The Dorsal Body Cavity encloses the CNS
Two subdivisions of Dorsal Body Cavity:
Cranial cavity
Encases brain
Vertebral cavity
Encloses spinal cord

27. The Ventral Body Cavity
Body Cavities
The Ventral Body Cavity
Houses soft internal organs (viscera)
Two subdivisions (separated by diaphragm):
Thoracic cavity
Abdominopelvic cavity

28. Cranial
cavity
Cranial
cavity
Dorsal body cavity
Ventral body cavity
Vertebral
cavity
Dorsal
body
cavity
Thoracic
Cavity
Vertebral
cavity
Ventral body
cavity
(thoracic and
abdominopelvic
cavities)
Diaphragm
Abdominal cavity
(contains digestive
viscera)
Abdomino-
pelvic
cavity
Pelvic cavity
(contains urinary
bladder, reproductive
organs, and rectum)
(a) Lateral view
(b) Anterior view
Figure 1.7

29. Thoracic Cavity subdivisions:
Ventral Body Cavities
Thoracic Cavity subdivisions:
Two pleural cavities
Each houses a lung
Mediastinum
Contains pericardial cavity
Also contains the esophagus and aorta
Pericardial Cavity
Encloses heart

30. Abdominopelvic Cavity subdivisions:
Ventral Body Cavities
Abdominopelvic Cavity subdivisions:
Abdominal Cavity
Contains stomach, intestines, spleen, and liver
Pelvic Cavity
Contains urinary bladder, reproductive organs, and rectum

31. Thoracic cavity Cranial cavity Vertebral cavity Cranial cavity
Dorsal body cavity
Ventral body cavity
Vertebral
cavity
Thoracic
cavity
Dorsal
body
cavity
Vertebral
cavity
Ventral body
cavity
Diaphragm
Abdominal cavity
Abdomino-
pelvic
cavity
Pelvic cavity
(a) Lateral view
(b) Anterior view
Figure 1.7

32. Abdominopelvic Regions
Nine Regions within the abdominopelvic area
Liver
Diaphragm
Right
hypochondriac
region
Left
hypochondriac
region
Epigastric
region
Gallbladder
Stomach
Right
lumbar
region
Left
lumbar
region
Ascending colon of
large intestine
Transverse colon
of large intestine
Umbilical
region
Small intestine
Descending colon
of large intestine
Cecum
Right iliac
(inguinal)
region
Hypogastric
(pubic)
region
Left iliac
(inguinal)
region
Initial part of
sigmoid colon
Appendix
Urinary bladder
(a) Nine regions delineated by four planes
(b) Anterior view of the nine regions showing the superficial organs
Figure 1.12