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Anatomy and Physiology I: An
Introductory Guide
Anatomy and Physiology I (Chattahoochee
Technical College)
Chapter 1: Introduction to the Human Body
Anatomy is the study of the structures of the body, while physiology is the study of the functions of those structures. The hierarchy of structural levels in the human body, from smallest to largest, is:
Chemical Level Cellular Level Tissue Level Organ Level Organ System Level Organism Level
A cell is the smallest independently functioning unit of a living organism. Tissues are groups of many similar cells that work together to perform a specific function. An organ is an anatomically distinct structure of the body composed of two or more tissue types. An organ system is a group of organs that work together to perform major functions or meet physiological needs of the body. An organism is a living being that has a cellular structure and can independently perform all physiological functions necessary for life.
The four main themes in physiology are: 1. Structure determines function. 2. Energy is required to maintain life. 3. Information flows between organ systems to coordinate function. 4. Organ systems maintain homeostasis, the body's ability to maintain a relatively stable internal environment.
The necessary life functions are organization, metabolism, responsiveness, movement, development, growth, and reproduction. Metabolism includes catabolism, the process of breaking down larger, more complex substances into smaller, simpler molecules, and anabolism, the process of combining smaller, simpler molecules into larger, more complex substances.
Control mechanisms in the body include negative feedback, which shuts off or reduces the intensity of the original stimulus, and positive feedback, which increases the original stimulus to push the variable farther, as seen in blood clotting or childbirth.
Anatomical Position, Directional Terms, and Body Planes
The anatomical position is standing straight up, with the palms facing anteriorly, the knees, elbows, and neck straight, and the toes pointing anteriorly but the fingertips pointing inferiorly.
Directional terms include: - Anterior/Ventral: toward the front of the body - Posterior/Dorsal: toward the back of the body - Superior: toward the head - Inferior: toward the feet - Medial: toward the midline of the body - Lateral: away from the midline of the body - Proximal: closer to the point of attachment or origin - Distal: farther from the point of attachment or origin
The body planes are the frontal (coronal), sagittal, and transverse planes.
The body cavities include the dorsal (posterior) cavity, which contains the cranial and vertebral cavities, and the ventral (anterior) cavity, which contains the thoracic and abdominopelvic cavities. The abdominopelvic cavity is further divided into the peritoneal, pelvic, and retroperitoneal cavities.
The serous membranes that line the body cavities include the parietal serosa, which forms the outer wall of the cavity, and the visceral serosa, which covers the organs within the cavity.
Chapter 2: Basic Biochemistry
Matter is anything that occupies space and has mass. Mass is the amount of matter in an object and is constant, while weight depends on gravity and is variable.
Energy is the capacity to do work and can take various forms, including chemical, electrical, mechanical, and radiant energy.
Elements are substances that cannot be broken down into simpler substances by ordinary chemical methods. Atoms are the smallest units of an element and are composed of subatomic particles, including protons, neutrons, and electrons. The atomic number is the number of protons, and the atomic weight is the average mass of all isotopes of a given element.
Molecules are combinations of two or more of the same element, while compounds are two or more different kinds of atoms bound together. Mixtures are two or more components that are physically intermixed, with the substance in the greatest amount being the solvent and the substance in the smaller amount being the solute.
Chemical bonds, including ionic, covalent, and hydrogen bonds, are formed by the exchange or sharing of electrons between atoms. Chemical reactions involve the formation, rearrangement, or breaking of chemical bonds, resulting in the change of one substance into another.
The energy flow of chemical reactions includes exergonic reactions, which release energy, and endergonic reactions, which absorb energy. Reaction rate can be influenced by factors such as temperature, concentration, particle size, and the presence of catalysts.
Organic compounds, which always contain carbon and are covalently bonded, include carbohydrates, lipids, proteins, and nucleic acids. Inorganic compounds, such as salts, water, acids, and bases, do not contain carbon.
Endoplasmic Reticulum (ER)
The endoplasmic reticulum functions as a manufacturing and packaging system, and is a network of membranes found throughout the cell and connected to the nucleus.
Smooth ER
The smooth ER acts as a storage organelle and is important in the creation and storage of lipids and steroids.
Rough ER
The rough ER is important in the synthesis and packaging of proteins. Ribosomes are attached to the membrane of the rough ER.
Golgi Apparatus
The Golgi apparatus manipulates products from the rough ER and produces lysosomes. It organizes, modifies, packages, and tags proteins for transport throughout the cell or export by exocytosis.
Lysosome
The lysosome is an organelle that contains enzymes that break down and digest unneeded cellular components, such as damaged organelles. It also digests foreign material.
Peroxisome
Peroxisomes contain enzymes that detoxify harmful substances and neutralize free radicals.
Mitochondria
Mitochondria are the energy conversion factories of the cell. They have a lipid bilayer membrane and produce ATP, the cell's major energy currency.
Cytoskeleton
The cytoskeleton gives shape to the cell and provides it with the capability to carry out cellular movements and aids in cell division. It contains paired centrioles that function in generating microtubules and organizing the mitotic spindle in cell division.
Cellular Extensions
Cilia are whip-like extensions that occur on exposed surfaces of certain cells and move substances across the cell's surface. Flagella function to propel
the cell along, as in the case of sperm cells. Microvilli are finger-like projections on the plasma membrane that increase the surface area.
Nucleus
The nucleus is the control center of the cell, containing the blueprints for the synthesis of proteins in the body in its genetic library. It has three main regions:
Nuclear Envelope
The nuclear envelope is a double membrane barrier separated by a fluid- filled space, with the outer layer studded with ribosomes.
Nucleolus
The nucleolus is the site where the assembly of ribosomes begins.
Chromatin
Chromatin is made of DNA, histone proteins, and RNA chains. The fundamental units are nucleosomes, which consist of 8 histone proteins wrapped together by DNA strands.
Cell Cycle
The cell cycle is a series of changes a cell goes through from the time it is formed to when it is replicated. It consists of three main phases:
Interphase
Interphase is the period from cell formation to cell division, during which the cell is growing and carrying out metabolic activity.
Mitosis
Mitosis is the phase where the cell divides into two identical cells (division of the nucleus).
DNA Replication
During the S phase of interphase, special enzymes, including helicase, untwist and separate the two strands of DNA. DNA polymerase then brings in the correct bases to complement the template strand, synthesizing a new strand base by base.
Ribosomal RNA (rRNA)
Ribosomal RNA (rRNA) forms the ribosome subunits that provide the site of protein synthesis.
Transcription and Translation
Transcription is the process where DNA information is encoded in mRNA. Translation is the process where the information carried by mRNA is decoded and used to assemble polypeptides.
