Human Biology Unit 1

Homeostasis

Existence of a stable internal environment; balance

Negative Feedback

Returns the body back to normal conditions by acting against the stimulus; homeostatic mechanism. Examples: sweating/shivering, insulin/glucagon, blood pressure regulation.

Positive Feedback

Intensifies or amplifies a change in the body’s physiological condition rather than reversing it, such as childbirth, blood clotting, inflammation as an immune response, breastfeeding.

Anatomy

Structure and parts

Physiology

How living organisms perform their vital functions

Receptor

Sensitive to stimuli, detects actual environmental conditions

Control Center

Receives and processes information and decides what to do about it

Effector

Responds to the commands of the control center and carries out the action

Dorsal-ventral

back to front

Distal-proximal

Distal (down) Proximal (up) (arms and legs)

Medial-lateral

Medial (to center of body) and lateral (away from center of body)

Superior-inferior

Superior (up) and inferior (down)

Frontal

front and back

Sagittal

left side to right side

Transverse

top half of body to bottom half of body

Pleura

surrounds each lung within the thoracic cavity

Pericardium

encloses the heart within the thoracic cavity

Peritoneum

lining the abdominopelvic cavity and protecting the digestive organs