Anatomy and Physiology Basics

Introduction

• Anatomy studies the structure and makeup of organisms.
• Gross anatomy looks at organs and their positions in the body.
• Microscopic anatomy studies tissues and cells, which cannot be seen without a microscope.
• Physiology studies the body's processes and functions.
• Homeostasis refers to the state of balance in which the body's organs and systems can function effectively.
• Pathophysiology is the study of how an organism functions when disease is present.
• Systemic anatomy involves studying each organ system separately.
• Regional anatomy studies specific regions of the body.

Overview of Body Systems

• The human body's building blocks include body parts, cavities, tissues, and organ systems.
• The skeletal system is composed of 206 bones, which provide support, movement, and protection.
• The muscular system has fibers that enable movement through contraction, which includes skeletal, smooth, and cardiac muscle.
• The circulatory system consists of the heart, blood vessels, and blood.
• The lymphatic system is a passive circulatory system that transports lymph.
• Lymph is a thin, plasma-like fluid formed from interstitial or extracellular fluid that bathes the body's tissues.
• The immune system is related to the lymphatic system and defends against foreign substances and disease.
• The respiratory system includes the organs and structures for breathing, gas exchange, and bringing air into the body.
• The nervous system is a complex structure that controls voluntary and involuntary body activities.
• The gastrointestinal system includes structures and organs involved in consuming, digesting, and eliminating food.
• The urinary system removes waste products from the blood through a filtration process that produces urine.
• The reproductive system consists of male and female structures for sexual reproduction.
• The endocrine system consists of glands throughout the body that secrete hormones to regulate functions.
• The integumentary system includes the skin, nails, hair, and sweat and oil glands.

Topographic Anatomy

• Superficial landmarks must be identified to make an accurate assessment of the body.
• Anatomic position is a universal position in which the body is standing upright and facing forward.
• Directional terms always pertain to the patient's right or left.
• The frontal (coronal) plane divides the body into front and back.
• The transverse (axial) plane divides the body into top and bottom.
• The sagittal (lateral) plane divides the body into left and right.
• Midsagittal plane divides the body into equal left and right halves.
• Directional terms describe the relative positions of body parts, relating to anatomic divisions.
• Superior refers to a structure that is closer to the head from a specific reference point.
• Inferior refers to a structure that is closer to the feet.
• Medial refers to being situated toward the midline or inner structure of an organ.
• Lateral refers to being situated away from the midline.
• Proximal refers to being nearer or toward the trunk of the body on an extremity.
• Distal refers to being farther from the trunk and toward the free end of an extremity.
• Anterior refers to the belly or the front side of the body, which is also known as ventral.
• Posterior refers to the spinal side or back of the body, which is also known as dorsal.
• A Midclavicular line is a vertical line drawn through the middle of the clavicle (collarbone), parallel to the midline.
• A midaxillary line is a vertical line drawn through the axilla (armpit) to the waist.
• Four abdominal quadrants are divided by two imaginary lines intersecting at the umbilicus.
• They include the right upper, left upper, right lower, and left lower quadrants.
• Specific organs are located in each quadrant, which can describe the location of pain or injury.

Movement and Positional Terms

• Movements can be broken down into a series of simple components described with specific terms.
• Range of motion (ROM) refers to the full distance that a joint can be moved.
• Flexion involves moving a distal point of an extremity closer to the trunk.
• Extension involves motion associated with returning a body part from a flexed position to anatomic position.
• Internal rotation refers to turning an extremity medially toward the midline, where the toes turn inward.
• External rotation turns an extremity away from the midline.
• Rotation can be applied to the spine, where it twists on its axis.
• Abduction involves moving an extremity away from the midline.
• Adduction involves moving an extremity toward the midline.
• Recumbent is when a patient is lying down or leaning back.
• Supine refers to a body resting on its back, with the face upward.
• Prone refers to a body lying with the face and abdomen downward.
• Trendelenburg's position includes the body being supine with the head lower than the feet.
• Fowler's position includes a patient sitting up with the knees bent or straight.
• Recovery (left lateral recumbent) position helps maintain an open airway in an unresponsive patient without neck trauma.

Basic Chemistry

• Chemistry is the study of matter, which is defined as anything that takes up space and has mass.
• Mass is a physical property that determines an object's weight, based on the earth's gravitational pull.
• Elements are fundamental substances that compose matter, whose atoms are the smallest complete units of an element.
• Protons have a positive electrical charge, neutrons have no charge, and electrons have a negative charge.
• An atom's mass is determined mostly by the number of protons and neutrons in the nucleus.
• The atomic number is the number of protons in an atom.
• Atomic weight is equal to the number of protons and neutrons in an element's nucleus.
• Isotopes are when an element's atoms have nuclei containing the same number of protons, but different numbers of neutrons.
• These can be radioactive which emits energetic particles known as radiation due to instability of the atomic nuclei.
• Radiation occurs in one of three forms: alpha, beta, and gamma, the most penetrating type.
• Molecules are chemical structures of atoms held together by covalent bonds that involve sharing of electrons.
• Chemical bonds are when atoms bond with other atoms.
• Inert atoms are chemically inactive.
• Ions are atoms that either gain or lose electrons and are electrically charged.
• Ionic bonds are bonds that form between ions
• Cations are ions with a positive charge.
• Anions are ions with a negative charge.
• Covalent bonds are where atoms complete their outer electron shells by sharing electrons.
• A single covalent bond occurs when a single pair of electrons is shared.
• A double covalent bond occurs when two pairs of electrons are shared.
• A triple covalent bond occurs when three pairs of electrons are shared.
• A polar molecule is a covalent bond that has an uneven distribution of charges (a covalent bond that does not share electrons equally), one end is negative, and one is positive.
• A hydrogen bond occurs when the positive hydrogen end of a polar molecule is attracted to the negative nitrogen or oxygen end of another polar molecule.
• Compounds are molecules made up of different bonded atoms.
• A molecular formula represents the numbers and types of atoms in a molecule like H2O for water, that signifies two atoms of hydrogen and one atom of oxygen.
• Structural formulas show how atoms are joined and arranged inside molecules using single and double lines.

Types of Chemical Reactions

• Synthesis reactions occur when two or more reactants (atoms) bond to form a more complex product or structure.
• Decomposition reactions occur when bonds within a reactant molecule break, forming simpler atoms, molecules, or ions.
• Exchange reactions occur when Reacting molecules are shuffled around to produce new products.
• Reversible reactions occur when the products of the reaction can change back into the reactants they originally were.
• Enzymes promote chemical reactions by lowering the activation energy requirements.
• Enzymes are catalysts that accelerate chemical reactions without being permanently changed or consumed.
• Electrolytes are substances that release ions in water.
• Acids are electrolytes that release hydrogen ions in water.
• Bases are electrolytes that release ions that bond with hydrogen ions.
• pH is the value used to measure hydrogen ion concentrations, determining if there is acidity or alkalinity.
• Measurements of less than pH 7 are considered acidic; measurements of more than pH 7 are considered basic or alkaline.
• The pH of blood usually ranges from 7.35 to 7.45.
• Acidosis is an abnormal physiologic state caused by a blood pH that is lower than 7.35.
• Alkalosis results from a blood pH that is higher than 7.45.
• Buffers are chemicals that resist pH changes by combining with excessive hydrogen ions, and contributing hydrogen ions when levels are reduced.

Chemical Constituents of Cells

• Organic chemicals contain the elements carbon and hydrogen.
• Inorganic chemicals do not contain carbon and hydrogen, release ions and electrolytes in water.
• Inorganic substances in body cells include oxygen, carbon dioxide, compounds known as salts, and water.
• Water is the most abundant compound in the human body.
• Solute is any substance that dissolves in water.
• Organic molecules are made up of long chains of carbon atoms linked by covalent bonds.
• Carbohydrates provide much of the energy required by the body's cells and help build cell structures that consist of carbon, hydrogen, and oxygen.
• Those with shorter chains are called sugars which includes simple sugars (monosaccharides) that have 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms (C6H1206).
• Lipids do not dissolve in water, and include fats and phospholipids.
• Triglycerides contain different saturated and unsaturated fatty acid combinations.
• Steroids are large lipid molecules that share a distinctive carbon framework.
• Proteins are the most abundant organic components of the body.
• Nucleic acids are large organic molecules (macromolecules) that carry genetic information or form structures within cells and composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus.
• They include deoxyribonucleic acid (DNA), which determines inherited characteristics, and ribonucleic acid (RNA), which manufactures specific proteins by using the information provided by DNA.