Anatomy and Physiology

• Anatomy is the study of the body's structure and its parts.
• Physiology is the study of the function of the body and its parts.
• Anatomy examines the body's composition, while physiology studies how these parts work and interact.
• Microscopic anatomy studies structures not visible to the naked eye.

  Cytology

  • Cytology is the study of cells.

  Histology

  • Histology is the study of tissues.
• Gross anatomy studies large, visible structures.

  Surface anatomy

  • Surface anatomy studies external features.

  Systemic anatomy

  • Systemic anatomy studies organ systems.

  Regional anatomy

  • Regional anatomy studies structures within a specific region.
• Anatomical variation refers to differences in anatomy among individuals.
• Physiological variation refers to the normal range of values influenced by sex, age, genetics, diet, environment, etc.

Levels of structural organization

• Chemical level: atoms and molecules
• Cellular level: cells are the basic units of life
• Tissue level: tissues consist of similar cells performing specific functions
• Organ level: organs are composed of two or more tissue types
• Organ system level: organ systems consist of different organs working together
• Organismal level: the organism is the sum of all structural levels working together

Characteristics of life

• Organization: Living things exhibit a specific organization at all levels
• Metabolism: Sum of all chemical reactions in the body

  Catabolism

  • Catabolism is the breakdown of complex substances into simpler building blocks

  Anabolism

  • Anabolism is the building of complex compounds from simpler building blocks, using energy
• Responsiveness: Ability to detect and respond to stimuli
• Movement: Includes motion of the whole body, individual organs, cells, and cell components
• Development: Changes an organism goes through during its lifetime

  Differentiation

  • Differentiation: Process in which unspecialized cells become specialized

  Growth

  • Growth is an increase in size
• Reproduction: Production of new organisms and new cells
• Excretion: Removal of waste products
• Digestion: Breaking down food into absorbable molecules
• Ingestion: Intake of food
• Absorption: Uptake of molecules into cells
• Circulation: Transport of molecules throughout the body

Homeostasis

• Homeostasis is maintaining a stable internal environment despite external changes
• Variables are factors that can change (e.g., temperature, blood glucose)
• Control systems maintain homeostasis

  Receptor (sensor)

  • The receptor monitors the environment and responds to changes

  Control center

  • The control center determines the set point and appropriate response

  Effector

  • The effector provides the means to respond to the stimulus
• Negative feedback reduces the intensity of the initial stimulus
• Positive feedback increases the intensity of the initial stimulus
• Homeostatic imbalance leads to disease

Anatomical terminology

• Anatomical position: Body erect, feet slightly apart, palms facing forward
• Superior: Above
• Inferior: Below
• Anterior (ventral): Front
• Posterior (dorsal): Back
• Medial: Toward the midline
• Lateral: Away from the midline
• Proximal: Closer to the origin of the body part
• Distal: Farther from the origin of the body part
• Superficial: Toward the surface
• Deep: Away from the surface

Body planes

• Sagittal plane divides the body into right and left parts, including midsagittal (median) and parasagittal planes
• Frontal (coronal) plane divides the body into anterior and posterior parts
• Transverse (horizontal) plane divides the body into superior and inferior parts
• Oblique section: Cuts made diagonally

Body cavities

• Dorsal body cavity:

  Cranial cavity

  • The cranial cavity contains the brain

  Vertebral cavity

  • The vertebral cavity contains the spinal cord
• Ventral body cavity:

  Thoracic cavity

  • The thoracic cavity contains the heart and lungs

  Abdominopelvic cavity

  • The abdominopelvic cavity contains the abdominal and pelvic organs
    • Serous membranes line the ventral body cavity and cover its organs:
      • Parietal serosa lines the cavity walls
      • Visceral serosa covers the organs
      • Serous fluid separates the serosae
    • Specific serous membranes include:
      • Pleura (lungs)
      • Pericardium (heart)
      • Peritoneum (abdominopelvic cavity)

Abdominopelvic regions and quadrants

• Regions divide the abdominopelvic cavity into nine areas
• Quadrants divide the abdominopelvic cavity into four areas

Medical imaging

• X-ray: Uses electromagnetic radiation to view bones and dense structures.
• Computed Tomography (CT): Uses X-rays to create cross-sectional images.
• Magnetic Resonance Imaging (MRI): Uses magnetic fields and radio waves to visualize soft tissues.
• Ultrasound: Uses sound waves to visualize soft tissues and organs.
• Positron Emission Tomography (PET): Uses radioactive tracers to visualize metabolic activity.

Basic chemistry

• Matter is anything that has mass and occupies space
• Matter exists in solid, liquid, and gaseous forms
• Energy is the capacity to do work

  Kinetic energy

  • Kinetic energy is energy in action

  Potential energy

  • Potential energy is stored energy
• Chemical energy is stored in chemical bonds
• Electrical energy results from the movement of charged particles
• Mechanical energy is energy directly involved in moving matter
• Electromagnetic energy travels in waves
• Energy can be converted from one form to another
• Elements are substances that cannot be broken down into simpler substances by ordinary chemical methods
  • Major elements in the body include oxygen, carbon, hydrogen, and nitrogen
  • Lesser elements make up 3.9% of body mass
  • Trace elements are present in tiny amounts
• Atoms are the smallest units of an element that retain its properties
  • Atoms are composed of protons, neutrons, and electrons
  • Protons have a positive charge, neutrons have no charge, and electrons have a negative charge
  • Protons and neutrons are found in the nucleus, while electrons orbit the nucleus

  Atomic number

  • Number of protons in an atom

  Mass number

  • Total number of protons and neutrons in an atom
  • Isotopes are atoms with the same number of protons but different numbers of neutrons
• Molecules are two or more atoms held together by chemical bonds
• Compounds are two or more different kinds of atoms chemically bonded together
• Mixtures are two or more components physically intermixed

  Solutions

  • Solutions are homogeneous mixtures

  Colloids

  • Colloids are heterogeneous mixtures

  Suspensions

  • Suspensions are heterogeneous mixtures with large, visible solutes
• Chemical bonds are energy relationships between atoms

  Ionic bonds

  • Ionic bonds are formed by the transfer of electrons

  Covalent bonds

  • Covalent bonds are formed by the sharing of electrons

  Hydrogen bonds

  • Hydrogen bonds are weak bonds formed between a hydrogen atom and another atom
• Chemical reactions involve the making or breaking of chemical bonds

  Synthesis reactions

  • Synthesis reactions involve atoms or molecules combining to form a larger, more complex molecule

  Decomposition reactions

  • Decomposition reactions involve the breakdown of a molecule into smaller molecules or atoms

  Exchange reactions

  • Exchange reactions involve both synthesis and decomposition
• Chemical reactions are affected by temperature, concentration, particle size, and catalysts

Biochemistry

• Inorganic compounds include water, salts, acids, and bases
• Water is the most abundant inorganic compound in the body
• Salts are ionic compounds that dissociate into ions in water
• Acids are substances that release hydrogen ions in solution
• Bases are substances that accept hydrogen ions in solution
• pH measures the concentration of hydrogen ions in a solution
• Buffers resist changes in pH
• Organic compounds contain carbon and are usually large and complex
• Carbohydrates include sugars and starches

  Monosaccharides

  • Monosaccharides are simple sugars

  Disaccharides

  • Disaccharides are two monosaccharides joined together

  Polysaccharides

  • Polysaccharides are many monosaccharides joined together
• Lipids include fats, oils, and waxes

  Triglycerides

  • Triglycerides are composed of glycerol and three fatty acids

  Phospholipids

  • Phospholipids are composed of glycerol, two fatty acids, and a phosphate group

  Steroids

  • Steroids are composed of four interlocking rings
• Proteins are composed of amino acids
  • Amino acids are joined together by peptide bonds
  • Proteins have four levels of structural organization: primary, secondary, tertiary, and quaternary
  • Enzymes are biological catalysts that speed up chemical reactions
• Nucleic acids include DNA and RNA

  DNA

  • DNA stores genetic information

  RNA

  • RNA is involved in protein synthesis
  • Nucleic acids are composed of nucleotides
  • ATP (adenosine triphosphate) is the primary energy-transferring molecule in cells

Cells

• Cells are the basic structural and functional units of life
• Plasma membrane: Outer boundary of the cell
• Cytoplasm: Intracellular fluid containing organelles
• Nucleus: Control center of the cell

Plasma membrane

• Lipid bilayer: Composed of phospholipids, cholesterol, and glycolipids
• Membrane proteins: Integral and peripheral proteins
• Functions: Selective barrier, cell communication, cell adhesion

Cytoplasm

• Cytosol: Intracellular fluid
• Organelles: Specialized cellular compartments
• Ribosomes: Site of protein synthesis
• Endoplasmic reticulum (ER):

  Rough ER

  • Rough ER is studded with ribosomes and involved in protein synthesis

  Smooth ER

  • Smooth ER is involved in lipid synthesis and detoxification
• Golgi apparatus: Modifies, sorts, and packages proteins and lipids
• Lysosomes: Contain digestive enzymes
• Mitochondria: Site of ATP production
• Peroxisomes: Detoxify harmful substances
• Cytoskeleton: Provides structural support and facilitates movement
  • Microfilaments
  • Intermediate filaments
  • Microtubules
• Centrosome and centrioles: Involved in cell division

Nucleus

• Nuclear envelope: Double membrane surrounding the nucleus
• Nucleolus: Site of ribosome assembly
• Chromatin: DNA and proteins

Cell growth and division

• Cell cycle: Series of changes a cell goes through from formation to division

  Interphase

  • During interphase, the cell grows and carries out its functions

  Mitotic phase

  • During the mitotic phase, the cell divides
    • Mitosis: Nuclear division
      • Prophase
      • Metaphase
      • Anaphase
      • Telophase
    • Cytokinesis: Cytoplasmic division
• Control of cell division is crucial for normal growth and repair

Protein synthesis

• DNA contains genetic information
• Gene: Segment of DNA that codes for a protein
• Transcription: DNA is transcribed into mRNA
• Translation: mRNA is translated into a protein
• Genetic code: Set of rules by which information encoded in genetic material (DNA or RNA) is translated into proteins

Tissues

• Tissues are groups of cells that are similar in structure and perform a common function
• Four basic tissue types:
  • Epithelial tissue
  • Connective tissue
  • Muscle tissue
  • Nervous tissue

Epithelial tissue

• Covers body surfaces and lines body cavities
• Functions: Protection, absorption, filtration, excretion, secretion, and sensory reception
• Characteristics:
  • Cellularity
  • Specialized contacts
  • Polarity
  • Support by connective tissue
  • Avascularity
  • Regeneration
• Classification:
  • Simple epithelium consists of a single layer of cells
  • Stratified epithelium consists of multiple layers of cells
    • Squamous: Flattened cells
    • Cuboidal: Cube-shaped cells
    • Columnar: Column-shaped cells
    • Transitional: Cells that change shape
• Glandular epithelium:

  Endocrine glands

  • Endocrine glands secrete hormones into the bloodstream

  Exocrine glands

  • Exocrine glands secrete products onto body surfaces or into body cavities

Connective tissue

• Supports, connects, and separates different types of tissues and organs in the body
• Functions: Binding and support, protection, insulation, transportation
• Characteristics:
  • Common origin in mesenchyme
  • Varying degrees of vascularity
  • Extracellular matrix
• Types:
  • Connective tissue proper:
    • Loose connective tissue
    • Dense connective tissue
  • Cartilage
  • Bone
  • Blood

Muscle tissue

• Muscle tissue is responsible for movement
• Types:
  • Skeletal muscle: Voluntary movement
  • Cardiac muscle: Involuntary movement (heart)
  • Smooth muscle: Involuntary movement (walls of hollow organs)

Nervous tissue

• Main component of the nervous system
• Functions: Communication and control
• Types of cells:

  Neurons

  • Neurons generate and conduct nerve impulses

  Neuroglia

  • Neuroglia support and protect neurons

Membranes

• Epithelial membranes:

  Cutaneous membrane

  • Cutaneous membrane: Skin

  Mucous membranes

  • Mucous membranes line body cavities that open to the exterior

  Serous membranes

  • Serous membranes line body cavities closed to the exterior
• Synovial membranes line joint cavities

Tissue repair

• Inflammation is the body's initial response to injury
• Organization: Blood clot is replaced by granulation tissue
• Regeneration and fibrosis:

  Regeneration

  • Regeneration: Replacement of damaged tissue with the same type of tissue

  Fibrosis

  • Fibrosis: Replacement of damaged tissue with scar tissue

Developmental aspects of tissues

• Primary germ layers:

  Ectoderm

  • Ectoderm gives rise to the epidermis and nervous system

  Mesoderm

  • Mesoderm gives rise to muscle, bone, and blood

  Endoderm

  • Endoderm gives rise to the lining of the digestive tract and respiratory system
• Tissues change with age

Anatomy studies the body's structure, while physiology studies its functions. Anatomy includes microscopic (cytology, histology) and gross (surface, systemic, regional) studies. Both anatomical and physiological variations exits between individuals depending on various internal and external factors.