1. The Human Body: Anatomical Responses, Regions, Directions, and Body Cavities
Credit: Carlos J Bidot Author 2006
Revised 2010

2. Gross Anatomy
Regional – all structures in one part of the body (such as the abdomen or leg)
Systemic – gross anatomy of the body studied by system
Surface – study of internal structures as they relate to the overlying skin

3. Developmental Anatomy
Traces structural changes throughout life
Embryology – study of developmental changes of the body before birth

4. Homeostasis
Homeostasis is the ability to maintain a relatively stable internal environment in an ever-changing outside world
The internal environment of the body is in a dynamic state of equilibrium
Chemical, thermal, and neural factors interact to maintain homeostasis

5. Homeostatic Balance The basic functions of organisms: Movement
Responsiveness/Irritability
Digestion
Metabolism
Excretion
Reproduction/growth

6. Homeostatic Balance Homeostatic regulation involves: A receptor
(afferent pathway)
A control center
(efferent pathway)
An effector
*the factor/event regulated = the variable

8. Homeostatic Balance Feedback:
Negative Feedback (common) – Control center depresses variable
Example--The Control of Body Temperature
Positive Feedback (rare) – Control center enhances variable
Example--Blood Clotting and childbirth contractions

9. Negative Feedback in glucose level

10. Positive Feedback in Blood Clotting

11. The Language of Anatomy

12. Anatomical Position Body erect Feet slightly apart
Palms facing forward
Thumbs point away from body
Figure 1.7a

13. Directional Terms
Superior and inferior – toward and away from the head, respectively
Anterior and posterior – toward the front and back of the body
Medial, lateral, and intermediate – toward the midline, away from the midline, and between a more medial and lateral structure

14. Directional Terms
Proximal and distal – closer to and farther from the origin of the body
Superficial and deep – toward and away from the body surface

15. Directional Terms
Table 1.1

16. Directional Terms
Table 1.1

17. Complete the following…
The wrist is ? to the hand
The breastbone is ? to the spine
The brain is ? to the spinal cord
The thumb is ? to the fingers
*remember anatomical position!

18. Regional Terms: Anterior View AKA ventral view
Axial – The main axis of body (head, neck, and trunk)
Appendicular – appendages or limbs
Figure 1.7a

19. Posterior View- AKA Dorsal view
Figure 1.7b

20. Body Planes Sagittal – divides the body into right and left parts
Midsagittal or medial – sagittal plane that lies on the midline
Frontal or coronal – divides the body into anterior and posterior parts
Transverse or horizontal (cross section) – divides the body into superior and inferior parts
Oblique section – cuts made diagonally

21. Body Planes
Figure 1.8

22. Anatomical Variability
Humans vary slightly in both external and internal anatomy
Over 90% of all anatomical structures match textbook descriptions, but:
Nerves or blood vessels may be somewhat out of place
Small muscles may be missing
Extreme anatomical variations are seldom seen

23. Body Cavities
Figure 1.9a

24. Body Cavities
Dorsal cavity protects the nervous system, and is divided into two subdivisions
Cranial cavity is within the skull and encases the brain
Vertebral cavity runs within the vertebral column and encases the spinal cord
Ventral cavity houses the internal organs (viscera), and is divided into two subdivisions: - Thoracic and Abdominopelvic cavities

25. Body Cavities
Figure 1.9b

26. Body Cavities
Thoracic cavity is subdivided into pleural cavities, the mediastinum, and the pericardial cavity
Pleural cavities – each houses a lung
Mediastinum – contains the pericardial cavity, and surrounds the remaining thoracic organs
Pericardial cavity – encloses the heart

27. Body Cavities
The abdominopelvic cavity is separated from the superior thoracic cavity by the dome-shaped diaphragm
It is composed of two subdivisions
Abdominal cavity – contains the stomach, intestines, spleen, liver, and other organs
Pelvic cavity – lies within the pelvis and contains the bladder, reproductive organs, and rectum

28. Ventral Body Cavity Membranes
Parietal serosa lines internal body walls
Visceral serosa covers the internal organs
Serous fluid separates the serosae (A serous membrane, especially one that lines the pericardial, pleural, and peritoneal cavities, enclosing their contents)

29. Ventral Body Cavity Membranes
Figure 1.10a

30. Ventral Body Cavity Membranes
Figure 1.10b

31. Other Body Cavities
Oral and digestive – mouth and cavities of the digestive organs
Nasal –located within and posterior to the nose
Orbital – house the eyes
Middle ear – contain bones (ossicles) that transmit sound vibrations
Synovial – joint cavities

32. Abdominopelvic Regions
Umbilical
Epigastric
Hypogastric
Right and left iliac or inguinal
Right and left lumbar
Right and left hypochondriac
Figure 1.11a

33. Organs of the Abdominopelvic Regions
Figure 1.11b

34. Abdominopelvic Quadrants
Right upper (RUQ)
Left upper (LUQ)
Right lower (RLQ)
Left lower (LLQ)
Figure 1.12