THE STRUCTURAL LEVELS OF ORGANIZATION AND MAJOR DIVISIONS OF THE BODY

Anatomy

Study of the structure of body parts and their relationship to one another

Physiology

Study of the function of body parts; how they work to carry out life-sustaining activities

Gross/macroscopic anatomy

The study of large, visible structures. Ex. kidney, brain, heart

Regional anatomy

Looks at all structures in a particular area of the body

System anatomy

Looks at just one system. Ex. Nervous, cardiovascular

Surface anatomy

Looks at internal structures as they relate to overlaying skin (what’s under the skin)

Microscopic anatomy

Structures too small to be seen by the naked eye (need a microscope)

Developmental anatomy

Studies anatomical and physiological development throughout life. Ex, bones changing as you grow

Chemical level

Atoms, molecules and organelles (most basic form of life)

Cellular level

Single cell

Tissue level

Groups of similar cells

Organ level

Two or more types of tissues

Organ system level

Organs that work together

Organismal level

All organ systems combined to make the whole organism

Body has 5 survival needs

1. Nutrients

2. Oxygen

3. Water

4. Normal body temperature

5. Atmospheric pressure

Homeostasis

Is the maintenance of relatively stable internal conditions despite continuous changes in the environment

Receptor(sensor)

• Monitors environment

• Respond to stimuli (things that cause changes in controlled variables)

Control center

• determines set point at which variable is maintained

• Receives input from receptors

• Determines appropriate response

Effector

• Receives output from control center

• Provides the means to respond

• Response either reduces stimulus(negative feedback) or enhances stimulus(positive feedback)

Negative feedback

• most used feedback mechanisms

• Reduces or shuts off original stimulus

• Ex. Regulating body temperature

Positive feedback

• Enhances or exaggerates the original stimulus

• Ex. Enhancement of labor contractions

Anatomical position

Standing straight, feet slightly apart, palms facing forward with thumbs pointing away

Superior(cranial)

Inferior(caudal)

Anterior(Ventral)

Posterior(dorsal)

Medial

Lateral

Intermediate

Proximal

Distal

Towards or at body surface

Superficial(external)

Away from the body surface;more internal

Deep(internal)

Axial

Head, neck, and trunk

Appendicular

Limbs

Sagittal plane

Divides body into left and right parts

Midsagittal (median) plane

Straight through the middle on midline

Parasagittal plane

Cut was off-center, not on midline

Frontal (coronal) plane

Decides body vertically into anterior and posterior parts (front and back)

Transverse (horizontal) plane

Divides into superior and inferior parts

Dorsal body cavity

Protects brain and spinal cord. Two subdivisions, cranial and vertebral cavities

Cranial cavity

Encase brain

Vertebral cavity

Encases spinal cord

Ventral body cavity

Houses the internal organs (collectively called viscera). Two subdivisions separated by diaphragm

Thoracic cavity

Two pleural cavities, one for each lung

Mediastinum

Contains pericardial(enclose heart) cavity. Surrounds other thoracic organs, like esophagus, trachea, etc

Abdominopelvic cavity

Abdominal cavity and pelvic cavity

Abdominal cavity

Contains stomach, intestines, spleen, and liver

Pelvic cavity

Contains urinary bladder, reproductive organs, and rectum

Serosa (serous membrane)

Thin, double layered membrane that covers surfaces in ventral body cavity

Parietal serosa

On the outside. Lines internal body cavity walls

Visceral serosa

Inside, touching. Covers internal organs (viscera).

Serous fluid

Fluid secreted by both layers of membrane

Right upper quadrant

Gallbladder, liver, etc.

Left upper quadrant

Stomach, spleen, pancreas, etc.

Right lower quadrant

Appendix, cecum, etc.

Left lower quadrant

Part of small and large intestine, etc