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

2. Overview of Anatomy and Physiology
Anatomy – the study of the structure of body parts and their relationships to one another
Gross or macroscopic
Microscopic
Developmental
Physiology – the study of the function of the body’s structural machinery

3. 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

4. Microscopic Anatomy Cytology – study of the cell
Histology – study of tissues

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

6. Specialized Branches of Anatomy
Pathological anatomy – study of structural changes caused by disease
Radiographic anatomy – study of internal structures visualized by X ray
Molecular biology – study of anatomical structures at a sub-cellular level

7. Physiology Considers the operation of specific organ systems
Renal – kidney function
Neurophysiology – workings of the nervous system
Cardiovascular – operation of the heart and blood vessels
Focuses on the functions of the body, often at the cellular or molecular level

8. Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular level Cells are made up of molecules 2
Atoms 1
Chemical level Atoms combine to form molecules
Smooth muscle tissue
Heart 3
Tissue level Tissues consist of similar types of cells
Cardiovascular system
Blood vessels
Epithelial tissue
Smooth muscle tissue
Blood vessel (organ) 6
Organismal level The human organism is made up of many organ systems
Connective tissue 4
Organ level Organs are made up of different types of tissues 5
Organ system level Organ systems consist of different organs that work together closely
Figure 1.1

9. Levels of Structural Organization (*VERY important*)
Chemical – atoms combined to form molecules
Cellular – cells are made of molecules
Tissue – consists of similar types of cells
Organ – made up of different types of tissues
Organ system – consists of different organs that work closely together
Organism – made up of the organ systems

10. Homeostasis
Imagine one day is very cold out, while the next day is very hot.
What effect does that have on your body temperature?
External environment – keeps changing
Internal environment - remains stable.
How?
Body has “Homeostatic Mechanisms”

11. 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

12. Feedback Loops
The beginning of a reflex pathway is a disturbance in a controlled parameter called a stimulus
The stimulus is detected by a sensor (receptor)
continuously monitoring the environment
when a change is detected, it sends out a signal
The signal travels from the receptor to the control (integrating) center 12

13. Feedback Loops
The control center evaluates the incoming signal, compares it to the homeostatic setpoint, and decides on the appropriate response
The control center sends out a signal to the effector
The effector is a cell or tissue that carries out the appropriate response to bring the parameter back to within normal limits (setpoint)

14. Types of Feedback Negative feedback Most common
The effector removes the cause of imbalance
Ex. Body temperature, blood pH
Positive feedback
The effector reinforces the stimulus (does not stop it)
Ex. Blood clotting, labor

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

17. 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

18. 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

19. Directional Terms
Table 1.1

20. Directional Terms
Table 1.1

21. Regional Terms: Anterior View
Axial – head, neck, and trunk
Appendicular – appendages or limbs
Specific regional terminology
Figure 1.7a

22. Regional Terms: Posterior View
Figure 1.7b

23. Activity!

24. Anatomical Locations Abdominal: abdominal region
Acromial: the point of the shoulder
Antebrachial: forearm
Antecubital: anterior surface of the elbow
Axillary: armpit
Brachial: upper arm
Buccal: cheek of the face
Calcaneal: heel of the foot
Carpal: wrist
Cephalic: head

25. Anatomical Locations Cervical: neck
Deltoid: round part of the shoulder
Digital: fingers and toes
Dorsum: back
Femoral: thigh
Frontal: forehead
Gluteal: buttocks
Hallux: big toe
Inguinal: groin
Lumbar: lower back
Mammary: breast

26. Anatomical Locations Mental: chin Nasal: Nose
Occipital: base of the skull
Olecranal: elbow
Oral: mouth
Orbital: bony eye socket
Otic: ear
Palmar: palm of hand
Patellar: Kneecap
Pedal: Foot

27. Anatomical Locations Pelvic: pelvis region
Perineal: area between anus and external genitals
Plantar: sole of foot
Pollex: thumb
Popliteal: behind the knee
Pubic: genital region
Sacral: lower back between the hips
Scapular: shoulder blade
Tarsal: ankle
Thoracic: chest
Vertebral: spine

28. 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

29. Body Planes
Figure 1.8

30. 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

31. Body Cavities
Figure 1.9a

32. 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

33. Body Cavities
Figure 1.9b

34. 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

35. 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

36. 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)

37. Ventral Body Cavity Membranes
Figure 1.10a

38. Ventral Body Cavity Membranes
Figure 1.10b

39. 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

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

41. Organs of the Abdominopelvic Regions
Figure 1.11b

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