Chapter 1

Anatomy

Study of body structure

Physiology

Study of body function

Gross anatomy

Study of structures visible to the naked eye

Microscopic anatomy

Study of structures too small to see without magnification

Cytology

Study of cells

Histology

Study of tissues

Levels of organization (order)

Chemical → Cellular → Tissue → Organ → Organ system → Organism

Chemical level

Atoms and molecules

Cellular level

Smallest living units (cells)

Tissue level

Groups of similar cells performing a common function

Organ level

Two or more tissue types working together

Organ system level

Group of organs working together

Organismal level

The whole living individual

Homeostasis

Maintaining stable internal conditions despite external change

Dynamic equilibrium

Small fluctuations around a set point

Negative feedback

Response reduces/reverses the original stimulus (most common)

Positive feedback

Response amplifies the original stimulus (rare, short-term)

Negative feedback example

Body temperature regulation

Positive feedback example

Blood clotting; childbirth contractions

Receptor

Sensor that detects a change (stimulus)

Control center

Determines response; compares to set point

Effector

Structure that carries out the response

Anatomical position

Standing upright, facing forward, arms at sides, palms forward

Anterior (ventral)

Toward the front

Posterior (dorsal)

Toward the back

Superior (cranial)

Toward the head

Inferior (caudal)

Toward the feet

Medial

Toward the midline

Lateral

Away from the midline

Proximal

Closer to the point of attachment

Distal

Farther from the point of attachment

Superficial

Toward the body surface

Deep

Away from the body surface

Sagittal plane

Divides body into left and right portions

Midsagittal plane

Divides body into equal left and right halves

Frontal (coronal) plane

Divides body into anterior and posterior portions

Transverse plane

Divides body into superior and inferior portions

Dorsal body cavity

Cranial cavity + vertebral (spinal) cavity

Ventral body cavity

Thoracic cavity + abdominopelvic cavity

Thoracic cavity

Contains lungs and heart; separated by mediastinum

Pleural cavities

Surround the lungs

Pericardial cavity

Surrounds the heart

Abdominal cavity

Contains most digestive organs

Pelvic cavity

Contains bladder, reproductive organs, rectum

Serous membrane

Double-layer membrane lining a ventral body cavity

Parietal serosa

Lines the cavity wall

Visceral serosa

Covers the organ surface