Chp 1

Homeostasis

The maintenance of a relatively stable internal environment despite external changes.

Feedback loop components

Components include receptor (detects change), control center (compares input to set point), and effector (carries out response).

Negative feedback

Reverses or opposes a change, stabilizing a variable near a set point.

Positive feedback

Amplifies or enhances a change, pushing toward a defined endpoint.

Anatomical position

Body erect, facing forward, arms at sides, palms facing forward, thumbs pointing away from body.

Superior (cranial)

Toward the head.

Inferior (caudal)

Toward the feet.

Medial

Toward the midline.

Lateral

Away from the midline.

Proximal

Closer to trunk/origin.

Distal

Farther from trunk/origin.

Body planes

Sagittal (left/right), Frontal (anterior/posterior), Transverse (superior/inferior).

Dorsal cavity

Contains cranial cavity (brain) and vertebral canal (spinal cord).

Ventral cavity

Contains thoracic cavity and abdominopelvic cavity.

Serous membranes

Membranes that line body cavities and cover organs, including parietal and visceral layers.

Pleura

Serous membrane surrounding the lungs.

Pericardium

Serous membrane surrounding the heart.

Peritoneum

Serous membrane surrounding abdominal organs.

Homeostasis

The maintenance of a relatively stable internal environment despite external changes.

Feedback loop components

Components include receptor (detects change), control center (compares input to set point), and effector (carries out response).

Negative feedback

Reverses or opposes a change, stabilizing a variable near a set point.

Positive feedback

Amplifies or enhances a change, pushing toward a defined endpoint.

Anatomical position

Body erect, facing forward, arms at sides, palms facing forward, thumbs pointing away from body.

Superior (cranial)

Toward the head.

Inferior (caudal)

Toward the feet.

Medial

Toward the midline.

Lateral

Away from the midline.

Proximal

Closer to trunk/origin.

Distal

Farther from trunk/origin.

Body planes

Sagittal (left/right), Frontal (anterior/posterior), Transverse (superior/inferior).

Dorsal cavity

Contains cranial cavity (brain) and vertebral canal (spinal cord).

Ventral cavity

Contains thoracic cavity and abdominopelvic cavity.

Serous membranes

Membranes that line body cavities and cover organs, including parietal and visceral layers.

Pleura

Serous membrane surrounding the lungs.

Pericardium

Serous membrane surrounding the heart.

Peritoneum

Serous membrane surrounding abdominal organs.

Anterior (ventral)

Toward or at the front of the body.

Posterior (dorsal)

Toward or at the back of the body.

Superficial (external)

Toward or at the body surface.

Deep (internal)

Away from the body surface; more internal.

Axial region

Part of the body that includes the head, neck, and trunk.

Appendicular region

Part of the body consisting of the limbs attached to the main body axis.

Parietal layer

Layer of a serous membrane that lines the internal walls of a body cavity.

Visceral layer

Layer of a serous membrane that directly covers the outer surface of internal organs.