Because structure determines function, the form of a body part dictates what it can do, known as the principle of complementarity of structure and function.
What are the levels of structural organization in the human body from simplest to most complex?
Atoms → Molecules → Organelles → Cells → Tissues → Organs → Organ systems → Organism.
What is the basic structural and functional unit of a living organism?
The cell is the fundamental structural and functional unit, capable of maintaining and perpetuating life.
Name the four basic tissue types in the human body.
Epithelial, connective, muscle, and nervous tissues.
What defines an organ in the human body?
An organ is a structure composed of at least two (usually four) tissue types that performs a specific function.
What is an organ system?
A group of organs that work closely together to accomplish a common purpose.
What is the standard anatomical position?
Body erect, feet slightly apart, palms facing forward with thumbs pointing away from the body.
What do the terms 'right' and 'left' refer to in anatomy?
They refer to the patient's or cadaver's right and left, not the observer's.
Define the directional term 'proximal'.
Closer to the origin of the body part or the point of attachment of a limb to the body trunk.
Define the directional term 'distal'.
Farther from the origin of a body part or the point of attachment of a limb to the body trunk.
What are the two fundamental divisions of the body?
1. Axial part: head, neck, and trunk; 2. Appendicular part: limbs attached to the axis.
Name the three common body planes.
Frontal (coronal), sagittal (median), and transverse (horizontal) planes.
What are the major dorsal body cavities and what do they contain?
Cranial cavity (houses the brain) and vertebral cavity (houses the spinal cord).
What are the major divisions of the ventral body cavity?
Thoracic cavity (pleural and pericardial cavities) and abdominopelvic cavity (abdominal and pelvic cavities).
What is homeostasis?
The maintenance of relatively stable internal conditions despite continuous external changes; a dynamic state of equilibrium.
What are the three components required for homeostatic regulation?
Receptor (sensor), control center, and effector.
What is the role of negative feedback in homeostasis?
It prevents sudden, severe changes by reducing or shutting off the original stimulus.
Give an example of a positive feedback mechanism.
Blood clotting or enhancement of labor contractions by oxytocin, where the response exaggerates the original stimulus.
What systems play a major role in maintaining homeostasis?
The nervous and endocrine systems.
What is the function of the autonomic nervous system (ANS) in homeostasis?
It controls involuntary responses like heart rate, blood pressure, respiratory rate, and digestion without conscious awareness.
What is a hormone?
A chemical substance released into extracellular fluid that regulates the metabolic function of other cells.
How does the hypothalamus contribute to homeostasis?
It acts as the master control center, coordinating responses through the ANS and endocrine system to regulate body functions.