The Human Body: Anatomical Regions, Directions, and Body

Cavities

Lab 1

Overview of Anatomy and Physiology

• AnatomyAnatomy – the study of the structure of body parts and their relationships to one another– Gross or macroscopic– Microscopic– Developmental

• PhysiologyPhysiology – the study of the function of the body’s structural machinery

Gross Anatomy

• RegionalRegional – all structures in one part of the body (such as the abdomen or leg)

• SystemicSystemic – gross anatomy of the body studied by system

• SurfaceSurface – study of internal structures as they relate to the overlying skin

Microscopic Anatomy

• CytologyCytology – study of the cell

• HistologyHistology – study of tissues

Developmental Anatomy

• Traces structural changes throughout life

• EmbryologyEmbryology – study of developmental changes of the body before birth

Specialized Branches of Anatomy

• Pathological anatomyPathological anatomy – study of structural changes caused by disease

• Radiographic anatomyRadiographic anatomy – study of internal structures visualized by X ray

• Molecular biologyMolecular biology – study of anatomical structures at a sub-cellular level

Physiology

• Considers the operation of specific Considers the operation of specific organ systemsorgan 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, Focuses on the functions of the body, often at the cellular or molecular leveloften at the cellular or molecular level

Physiology

• Understanding physiology also requires a knowledge of physics, which explains electrical currents, blood pressure, and the way muscle uses bone for movement

Principle of Complementarity

• Function always reflects structure

• What a structure can do depends on its specific form

Chemical levelAtoms combine to form molecules

1

2

3

4

Cellular levelCells are made up of molecules

Tissue levelTissues consist of similar types of cells

5 Organ system levelOrgan systems consist of different organs that work together closely

Organ levelOrgans are made up of different types of tissues

6 Organismal levelThe human organism is made up of many organ systems

Atoms

Molecules

Smooth muscle cell

Smooth muscle tissue

Connective tissue

Smooth muscle tissue

Epithelial tissue

Blood vessel (organ)

Heart

Blood vessels

Cardiovascular system

Levels of Structural Organization

Figure 1.1

Levels of Structural Organization• ChemicalChemical – atoms combined to form molecules

• CellularCellular – cells are made of molecules

• TissueTissue – consists of similar types of cells

• OrganOrgan – made up of different types of tissues

• Organ systemOrgan system – consists of different organs that work closely together

• OrganismalOrganismal – made up of the organ systems

Homeostasis

• HomeostasisHomeostasis 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 equilibriuma dynamic state of equilibrium

• Chemical, thermal, and neural factors interact to maintain homeostasis

Homeostatic Imbalance

• Disturbance of homeostasis or the Disturbance of homeostasis or the body’s normal equilibriumbody’s normal equilibrium

• Overwhelming of negative feedback mechanisms allowing destructive positive feedback mechanisms to take over

Anatomical Position

• Body erect

• Feet slightly apart

• Palms facing forward

• Thumbs point away from body

Figure 1.7a

Directional Terms

• Superior and inferiorSuperior and inferior – toward and away from the head, respectively

• Anterior and posteriorAnterior and posterior – toward the front and back of the body

• Medial, lateral, and intermediateMedial, lateral, and intermediate – toward the midline, away from the midline, and between a more medial and lateral structure

Directional Terms

• Proximal and distalProximal and distal – closer to and farther from the origin of the body

• Superficial and deepSuperficial and deep – toward and away from the body surface

Directional Terms Table 1.1

Directional Terms Table 1.1

Regional Terms: Anterior View

• AxialAxial – head, neck, and trunk

• AppendicularAppendicular – appendages or limbs

• Specific Specific regional regional terminologyterminology

Figure 1.7a

Regional Terms: Posterior View

Figure 1.7b

Body Planes• SagittalSagittal – divides the body into right and

left parts

• Midsagittal or medialMidsagittal or medial – sagittal plane that lies on the midline

• Frontal or coronalFrontal or coronal – divides the body into anterior and posterior parts

• Transverse or horizontalTransverse or horizontal (cross section) – divides the body into superior and inferior parts

• Oblique sectionOblique section – cuts made diagonally

Body Planes Figure 1.8

Anatomical Variability

• Humans vary slightly in both external Humans vary slightly in both external and internal anatomyand 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 Extreme anatomical variations are seldom seenseldom seen

Body Cavities

Figure 1.9a

Body Cavities• Dorsal cavityDorsal 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 cavityVentral cavity houses the internal organs (viscera), and is divided into two subdivisions: - Thoracic and Abdominopelvic cavities

Body CavitiesFigure 1.9b

Body Cavities

• Thoracic cavityThoracic 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

Body Cavities• The abdominopelvic cavity is separated The abdominopelvic cavity is separated

from the superior thoracic cavity by the from the superior thoracic cavity by the dome-shaped diaphragmdome-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

Ventral Body Cavity Membranes

• Parietal serosaParietal serosa lines internal body walls

• Visceral serosaVisceral serosa covers the internal organs

• Serous fluid separates the serosae

Ventral Body Cavity Membranes

Figure 1.10a

Ventral Body Cavity Membranes

Figure 1.10b

Other Body Cavities

• Oral and digestiveOral and digestive – mouth and cavities of the digestive organs

• NasalNasal –located within and posterior to the nose

• OrbitalOrbital – house the eyes

• Middle earMiddle ear – contain bones (ossicles) that transmit sound vibrations

• SynovialSynovial – joint cavities

Abdominopelvic Regions

• Umbilical

• Epigastric

• Hypogastric

• Right and left iliac or inguinal

• Right and left lumbar

• Right and left hypochondriac

Figure 1.11a

Organs of the Abdominopelvic Regions

Figure 1.11b

Abdominopelvic Quadrants

• Right upper (RUQ)

• Left upper (LUQ)

• Right lower (RLQ)

• Left lower (LLQ)

Figure 1.12

Assignments• Study and answer the exercises of

Chapter 1 • Review sheets