A&P I Test #1 9-10-12 UDL

Foundations of Anatomy and Physiology

• Anatomy: The study of body structure and the physical relationships among body parts.

• Physiology: The study of biological function and how living organisms carry out vital processes.

  • Example of a Physiological Study: Determining normal blood sugar levels for $20\,\text{year old}$ students (evaluates functional metabolic parameters rather than physical structure).

  • Examples of Anatomical Studies: Observing the interior structure of the heart, studying a kidney model, examining bone surfaces, or viewing muscle tissue through a microscope.

• Levels of Structural Organization: The human body is organized in increasing order of structural complexity:

  1. Organelle Level: Specialized subcellular structures that execute specific functions within a cell (e.g., mitochondria, ribosomes).

  2. Cellular Level: The basic structural and functional unit of life (e.g., nerve cells, muscle fibers).

  3. Tissue Level: Aggregations of similar cells working together to perform a shared function (e.g., epithelial tissue, connective tissue).

  4. Organ Level: Structures composed of two or more tissue types integrated to perform complex tasks (e.g., heart, kidney).

  5. Organ System Level: Groups of organs executing broad biological functions (e.g., cardiovascular system).

  • Correct Hierarchy Progression: Organelle $\rightarrow$ Cell $\rightarrow$ Tissue $\rightarrow$ Organ $\rightarrow$ Organ System.

• Responsiveness: The biological capacity of an organism or cell to sense and react to environmental changes.

  • Example: Nerve cells generating electrical signals in response to environmental stimuli.

• Homeostasis and Feedback Systems:

  • Homeostasis: The maintenance of a dynamic, relatively stable internal environment despite fluctuations in external conditions.

  • Negative Feedback Mechanism: A primary homeostatic control mechanism in which the response of the effector reverses the original stimulus, bringing the physiological variable back toward its set point.

  • Positive Feedback Mechanism: A mechanism where the response of the effector enhances or intensifies the original stimulus, driving the system further away from its initial state until a definitive endpoint is achieved.

• Organ Systems: Recognized anatomical organ systems include the integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and reproductive systems.

  • Terminology Distinction: "Hormonal" describes a mode of chemical regulation within the endocrine system and is not the proper name of an anatomical organ system.

Anatomical Terminology, Body Planes, and Cavities

• Standard Anatomical Position:

  • The body stands erect, facing forward, with feet flat and directed anteriorly.

  • Arms are placed at the sides with the palms of the hands on the anterior surface (facing forward) and thumbs pointing away from the body midline.

• Directional Terms:

  • Distal vs. Proximal: Direct opposites along a limb. Distal refers to a position farther from the point of attachment to the trunk; proximal refers to a position closer to the point of attachment.

  • Dorsal (Posterior): Toward the back of the body.

  • Ventral (Anterior): Toward the front/belly of the body.

  • Superior vs. Inferior: Above (toward the head) vs. below (toward the feet).

  • Medial vs. Lateral: Toward the midline of the body vs. away from the midline.

  • Deep vs. Superficial: Farther internal from the body surface vs. closer to the body surface.

• Body Planes and Sections:

  • Sagittal Plane: A vertical plane dividing the body into right and left portions. A median (midsagittal) plane divides the body into equal halves.

  • Coronal (Frontal) Plane: A vertical plane separating the body into anterior (front) and posterior (back) portions. A section severing the nose off a face occurs along the coronal plane.

  • Transverse (Horizontal) Plane: A horizontal plane dividing the body into superior (upper) and inferior (lower) portions.

• Body Cavities and Spatial Hierarchy:

  • The ventral body cavity is divided into thoracic and abdominopelvic cavities.

  • Pelvic Cavity: Positioned most inferiorly among the ventral cavities, situated below the abdominal cavity, diaphragm, mediastinum, pleural cavity, and pericardial cavity.

• Serous Membranes:

  • Parietal Layer: Lines the outer walls of ventral body cavities.

  • Visceral Layer: Direct inner layer covering the surface of internal organs (viscera).

  • Parietal Peritoneum: The serous membrane lining the outer wall of the abdominopelvic cavity.

• Anatomical Location of the Heart: Described using four principal directional terms:

  1. Superior to the diaphragm.

  2. Medial to the lungs (occupying the mediastinum).

  3. Posterior to the sternum and anterior to the thoracic vertebrae.

  4. Deep to the pericardial membrane and chest wall.

Chemical and Cellular Foundations of Life

• Subatomic Structure of Matter:

  • Atom: The smallest unit particle of an element that retains the chemical characteristics of that element.

  • Proton: Located in the nucleus, possesses a single positive charge ($+1$), and has an atomic mass of $1\,\text{amu}$.

  • Neutron: Located in the nucleus, possesses no electrical charge ($0$), and has an atomic mass of $1\,\text{amu}$.

  • Electron: Located in orbital shells surrounding the nucleus, possesses a single negative charge ($-1$), has negligible mass, and is the primary subatomic particle involved in chemical bonding behavior.

• Isotopes and Ions:

  • Isotopes: Chemical variants of an element containing the same atomic number (number of protons) but differing mass numbers due to variations in neutron count.

  • Cation: A positively charged ion formed when a neutral atom loses one or more valence electrons.

  • Anion: A negatively charged ion formed when a neutral atom gains one or more valence electrons.

• Chemical Bonds and Molecular Polarity:

  • Ionic Bonding: Chemical bonding resulting from the complete transfer of electrons from one atom to another