Anatomy and Physiology - Chapter 1 Flashcards

Gross Anatomy

  • Is the study of the LARGER STRUCTURES of the body, those visible WITHOUT the aid of MAGNIFICATION.
  • Organs such as the brain and lungs
  • aka macroscopic anatomy

Microscopic Anatomy

  • Is the study of structures that can be observed ONLY with the use of a MICROSCOPE or other magnification device
  • Includes the CYTOLOGY, the study of cells, and HISTOLOGY, the study of tissues

Regional Anatomy

  • Is the study of the INTERELATIONSHIPS of ALL of the STRUCTURES in a SPECIFIC BODY REGION
  • E.g. the abdomen or thoracic
  • Studying regional anatomy helps one to appreciate the INTERRELATIONSHIPS of body structures, such as how muscles, nerves, blood vessels, and other STRUCTURES work TOGETHER to serve a particular body region.

Systemic Anatomy

  • Is the study of the STRUCTURES that make up a DISCRETE BODY system --- that is, a group of structures (organs) that work TOGETHER to perform a UNIQUE body FUNCTION
  • E.g. a systemic anatomical study of the muscular system would consider ALL the SKELETAL MUSCLES of the body.

Physiology

  • Is the scientific STUDY of the CHEMISTRY & PHYSICS of the STRUCTURES of the body and the WAYS in which THEY work TOGETHER to SUPPORT the FUNCTIONS of LIFE
  • Most of the study of physiology centers on the body’s tendency toward HOMEOSTASIS
  • Like anatomists, physiologists typically specialize in a particular branch of physiology
  • E.g. neurophysiology is the study of the brain, spinal cord, and nerves and how these work TOGETHER to perform FUNCTIONS as complex and diverse as vision, movement, and thinking
  • Physiologists may work from the ORGAN level (exploring, for example, what different parts of the brain do) to the MOLECULAR level (such as exploring how an electrochemical signal travels along nerves)
  • FORM dictates FUNCTION!

Structural Organization of the Human Body

  • Before one begins to study the different structures (forms) and functions of the human body, it is helpful to consider its basic ARCHITECTURE.
  • How its SMALLEST parts are assembled into LARGER structures
  • 6 DISTINCT Levels of INCREASING Structural COMPLEXITY of the Human Body
    1. Chemical level
    2. Cellular level
    3. Tissue level
    4. Organ level
    5. Organ system level
    6. Organismal level
  • 9 Fundamental Levels of Organization:
    1. Subatomic particles
    2. Atoms
    3. Molecules
    4. Organelles
    5. Cells
    6. Tissues
    7. Organs
    8. Organ Systems
    9. Organismal

Cell

  • Is the smallest independently functioning unit of a living organism.
  • All living structures of human anatomy contain cells
  • And almost all functions of human physiology are performed in cells or are initiated by cells.
  • Cells consists of a flexible phospholipid bilayer membrane that enclose its cytoplasm, a water-based cellular fluid (cytosol) together with a variety of tiny functioning units called organelles.
  • In humans, as in all organisms, cells perform all functions of life.

Tissue

  • Is a group of many similar cells that work together to perform a SPECIFIC FUNCTION.

Organ

  • Is an anatomically DISTINCT structure of the body COMPOSED of two or more TISSUE types.
  • Each organ performs one or more SPECIFIC physiological functions.

Organ system

  • Is a GROUP of ORGANS that work TOGETHER to perform MAJOR FUNCTIONS or MEET PHYSIOLOGICAL needs of the body.

  • This textbook covers 11 DISTINCT organ systems in the human body.

    1. Integumentary System
    2. Muscular System
    3. Endocrine System
    4. Skeletal System
    5. Nervous System
    6. Cardiovascular System
    7. Lymphatic System
    8. Digestive System
    9. Respiratory System
    10. Urinary System
    11. Male/Female Reproductive Sys

  • Assigning organs to organ systems can be IMPRECISE since organs that “BELONG” to one system can also HAVE FUNCTIONS INTEGRAL to another system.

  • In fact, MOST ORGANS contribute to more than 1 system.

Functions of Human Life

  • The different organ systems each have different functions and therefore unique roles to perform in physiology.
  • These many functions can be summarized in 6 terms that we might consider DEFINITIVE of human life.
    • Organization
    • Metabolism
    • Responsiveness
    • Movement
    • Development
    • Reproduction

Organization (compartmentalization)

  • A human body consists of TRILLIONS of cells ORGANIZED in a way that maintain distinct INTERNAL COMPARTMENTS.
  • These COMPARTMENTS Keep body cells SEAPARTED from EXTERNAL environmental threats and keep the cells MOIST and NOURISHED.
  • These COMPARTMENTS also separate internal fluids from countless microorganisms that grow on body surfaces, including the LINING of certain tracts, or passageways.
  • For example, the GI tract is home to even more bacteria cells than the total of ALL human cells.
  • Cells’ plasma membrane.
  • Blood vessels keep blood inside a closed circulatory system.
  • Nerves & muscles are wrapped in connective tissue sheaths that separate them from surrounding structures.
  • In the chest & abdomen, a variety of INTERNAL MEMBRANES keep major organs such as the lungs, heart, & kidneys SEPARATE from others.
  • The surface of the SKIN protects the body’s internal environment.

Metabolism

  • The 1st law of thermodynamics holds that energy can neither be created nor destroyed-----it can only change form
  • The body’s basic function as an organism is to consume (ingest) energy and molecules in the foods one eats, CONVERT some of the food into FUEL for movement, sustain one’s body functions, and BUILD and MAINTAIN one’s body structures.
  • There are 2 types of REACTIONS that accomplish this:
    • ANABOLISM
    • CATABOLISM

Anabolism

  • Is the process whereby SMALLER, SIMPLER molecules are COMBINED into LARGER, more COMPLEX substances.
  • The body can assemble, by utilizing energy, the complex chemicals it needs by COMBINING small molecules derived from the foods it consumes.

Catabolism

  • Is the process by which LARGER more COMPLEX substances are BROKEN DOWN into SMALLER SIMPLER molecules.
  • Catabolism RELEASES energy.
  • The complex molecules found in foods are broken down so the body can use their parts to ASSEMBLE the structures and substances NEEDED for LIFE.
  • METABOLISM is the SUM of all ANABOLIC & CATABOLIC REACTIONS that take place in the body.
  • BOTH anabolism & catabolism occur simultaneously & continuously to keep a person ALIVE!
  • Cells in the body makes use of a chemical compound, adenosine triphosphate (ATP), to STORE and RELEASE energy.

Responsiveness

  • Is the ability of an organism to ADJUST to CHANGES in its INTERNAL & EXTERNAL environments.
  • For example, moving TOWARD sources of water & food and AWAY from perceived dangers, or vasomotor changes to temperature changes.

Movement

  • Human movement includes not only actions at the joints of the body, but also the motion of individual organs and even individual cells.

Development

  • Is all of the changes the body goes through in life.
  • It includes DIFFERENTIATION
  • This is where UNSPECIALIZED cells become SPECIALIZED in structure & function to perform certain tasks in the body.
  • Also includes the processes of GROWTH & REPAIR, both of which involve cell DIFFERENTIATION.

Growth

  • Is the INCREASE in body SIZE.
  • Humans, like all MULTICELLULAR organisms, grow by INCREASING the NUMBER of EXISTING cells, or by INCREASING the AMOUNT of non-cellular material around cells (such as mineral deposits in bone), and, within very narrow limits, INCREASING the Size of EXISTING cells.

Reproduction

  • Is the FORMATION of a NEW organism from PARENT organisms.
  • In humans, reproduction is carried out by the male & female reproduction systems.

4 Requirements for Human Life

  1. OXYGEN
    • Atmospheric AIR is only about 20% oxygen, but that oxygen is a KEY component of the chemical reactions that keep the body alive, including the reactions that produce ATP
    • Brain cells are especially sensitive to the LACK of oxygen because of their requirement for a high-and-steady production of ATP
    • Brain damage is likely within 5 minutes without oxygen, and death is likely within 10 minutes.
  2. NUTRIENTS
    • Are substances in foods and beverages that are essential to human survival.
    • 3 basic classes of nutrients:
      • Water – the most CRITICAL one
      • Energy-yielding nutrients (primarily carbohydrates & lipids) and body-building (proteins/amino acids) nutrients
      • Micronutrients (vitamins & minerals)
  3. Narrow Range of TEMPERATURE
    • Chemical reactions upon which the body depends can only take place within a NARROW RANGE of body temperature.
    • From just BELOW to just ABOVE 37 C (98.6 F)
    • When body temperature RISES well ABOVE or DROPS well BELOW normal, certain proteins (ENZYMES) that facilitate chemical reactions LOSE their normal STRUCTURE and then their ABILITY to FUNCTION and the chemical reactions of METABOLISM cannot proceed.
    • The body can respond effectively to SHORT-TERM exposure to heat or cold
      • Heat = SWEATING and vasodilation
      • Cold = SHIVERING and vasoconstriction
  4. Narrow Range of ATMOSPHERIC PRESSURE
    • It is the pressure exerted by the mixture of GASES (primarily nitrogen & oxygen) in the Earth’s atmosphere.
    • PRESSURE is a FORCE exerted by a substance that is in contact with another substance.
    • Atmospheric pressure is constantly pressing down on the body.
    • This pressure KEEPS GASES within the body, such as the gaseous nitrogen in body fluids, dissolved.
    • The ability of a person to breathe depends upon a precise atmospheric pressure.

Homeostasis

  • Maintenance of relatively stable internal conditions despite continuous changes in its environment
  • It is a dynamic state of equilibrium
  • Maintained by contributions of all organ systems

Homeostatic Control Mechanisms

  • Homeostasis involves continuous monitoring and regulation of all factors that can change (variables)
  • Communication is necessary for monitoring and regulation
  • Functions of the Nervous and Endocrine systems
  • The Nervous and Endocrine systems accomplish communication via nerve impulses and hormones

Components of a Control Mechanism

  • Receptor (sensor)
    • Monitors the internal and external environments
    • Responds to stimuli (something that causes changes in controlled variables)
  • Control center
    • Determines the set point at which the variable is to be maintained
    • Receives input from receptors
    • Determines the appropriate response
  • Effector
    • Receives output from control center
    • Provides the means to respond
    • The Response either reduces (negative feedback) or enhances stimulus (positive feedback)

Negative Feedback

  • Most feedback mechanisms in the body uses this
  • Response reduces or shuts off the original stimulus
  • The Variable changes in opposite direction of initial change
  • Examples
    • Regulation of body temperature (a nervous system mechanism)
    • Regulation of blood glucose by insulin (an endocrine system mechanism)

Negative Feedback: Regulation of Blood Volume by ADH

  • Receptors sense decreased blood volume
  • Control center in hypothalamus stimulates the pituitary gland to release antidiuretic hormone (ADH)
  • ADH causes kidneys (effectors) to return more water to the blood

Positive Feedback

  • Response enhances or exaggerates the original stimulus
  • May exhibit a cascade or amplifying effect
  • Usually controls infrequent events that do not require continuous adjustment
    • Enhancement of labor contractions by oxytocin (chapter 28)
    • Platelet plug formation and blood clotting

Homeostatic Imbalance

  • Disturbance of homeostasis
  • Increases the risk of disease
  • Contributes to changes associated with aging
    • Because control systems become less efficient
  • If negative feedback mechanisms become overwhelmed
    • Destructive positive feedback mechanisms may take over (e.g., heart failure)

Anatomical Terminology

  • The purpose of anatomical terminology language is not to confuse, but rather to increase PRECISION and reduce MEDICAL ERRORS.
  • By using PRECISE anatomical terminology, we try to ELIMINATE ambiguity!
  • Anatomical terms DERIVE from ancient GREEK & LATIN words
  • Because these languages are no longer used in everyday conservation, the meaning of their words does NOT CHANGE.
  • Anatomical terms are made up of ROOTS, PREFIXES, and SUFFIXES.
  • The ROOT of a term often refers to an organ, tissue, or condition
  • The PREFIX & SUFFIX often DESCRIBES the ROOT.
  • E.g. HYPERtension = high or over pressure. High blood pressure.

Anatomical Position

  • To further increase precision, anatomists & clinicians STANDARDIZE the way in which they VIEW the body.
  • Anatomical Position = is that of the body STANDING UPRIGHT, with the FEET shoulder width apart and parallel, with TOES forward. The UPPER LIMBS are held OUT to each side, and the PALMS of the HANDS face FORWARD.
  • Using this STANDARD POSITION reduces confusion
  • It does not matter how the body being described is actually oriented, the terms are used as if IT IS IN the anatomical position.

Regional Terms

  • The human body’s numerous regions have SPECIFIC terms to help increase precision
  • Brachium or arm = the “upper arm”
  • Antebrachium or forearm = “lower arm”
  • Femur = “thigh”, which describes the portion of the “lower limb” from the hip joint down to and includes the knee.
  • Crus = “leg”, which describes the portion of the “lower limb” BETWEEN the knee and the ankle.

Directional Terms

  • These TERMS are ESSENTIAL for describing the RELATIVE LOCATIONS (always includes 2 things) of DIFFERENT body structures.
  • For instance, a clinician might describe one band of tissue as “INFERIOR TO” another. ( 2 things)
  • Or a clinician might describe a tumor (1 thing) as “SUPERFICIAL TO” a deeper body structure (the 2nd thing)
  • Commit ALL the Directional TERMS to MEMORY
    • Anterior (or ventral) describes the front or direction toward the front of the body. The toes are anterior to the foot.
    • Posterior (or dorsal) describes the back or direction toward the back of the body. The popliteus is posterior to the patella.
    • Superior (or cranial) describes a position above or higher than another part of the body proper. The orbits are superior to the oris.
    • Inferior (or caudal) describes a position below or lower than another part of the body proper; near or toward the tail (in humans, the coccyx, or lowest part of the spinal column). The pelvis is inferior to the abdomen.
    • Lateral describes the side or direction toward the side of the body. The thumb (pollex) is lateral to the digits.
    • Medial describes the middle or direction toward the middle of the body. The hallux is the medial toe.
    • Proximal describes a position in a limb that is nearer to the point of attachment or the trunk of the body. The brachium is proximal to the antebrachium.
    • Distal describes a position in a limb that is farther from the point of attachment or the trunk of the body. The crus is distal to the femur.
    • Superficial describes a position closer to the surface of the body. The skin is superficial to the bones.
    • Deep describes a position farther from the surface of the body. The brain is deep to the skull.

Body Sections & Planes

  • SECTION

    • Is a two-dimensional SURFACE of a three-dimensional STRUCTURE that has been CUT.
    • Modern medical IMAGING DEVICES enable clinicians to obtain “virtual sections” of LIVING bodies.
    • We call these SCANS.
    • Body sections & scans can be clinically interpreted ONLY if the viewer UNDERSTANDS the PLANE along which the section was made.

  • PLANE

    • A plane is an IMAGINARY two-dimensional surface (blade) that passes THROUGH the body.
    • There are 3 PLANES commonly referred to in anatomy and medicine.
    1. Sagittal Plane: divides the body or an organ VERTICALLY into RIGHT and LEFT sides.
      • MIDsagittal/median plane = equal sides
      • Parasagittal/longitudinal plane = Unequal sides
    2. Frontal/coronal Plane: divides the body or an organ into ANTERIOR (front) AND a POSTERIOR (rear) portions.
    3. Transverse plane/cross section: divides the body or an organ HORIZONTALLY into UPPER and LOWER portions.

Body Cavities & Serous Membranes

  • The body MAINTAINS its INTERNAL organization (compartmentalization) by means of MEMBRANES, SHEATHS, and OTHER structures that SEPARATEcompartments/Cavities.
  • These CAVITIES contain and protect delicate internal organs
  • The VENTRAL cavity ALLOWS significant changes in the size and shape of the organs as they perform their functions.
  • The lungs, heart, stomach, and intestines, for example, can EXPAND and CONTRACT without DISTORTING other tissues or DISRUPTING the activity of nearby organs.

Subdivisions of the Dorsal (posterior) & Ventral (anterior) Cavities

  • They are each divided into SMALLER cavities
  • The Dorsal Cavity is divided into:
    • The CRANIAL cavity --- houses the brain
    • The SPINAL Cavity aka Vertebral Cavity --- encloses the spinal cord
  • The Ventral Cavity is divided into 2 MAIN subdivisions:
    • The THORACIC Cavity --- enclosed by the rib cage
      • Contains the heart & lungs in the mediastinum. The diaphragm forms its floor that separates it from the more inferior 2nd main subdivision.
    • The ABDOMINOLEPVIC Cavity --- the LARGEST CAVITYin the body. It has 2 subdivisions
      1. Abdominal Cavity
      2. Pelvic Cavity

Membranes of the Anterior (Ventral) Body Cavity

  • A SEROUS MEMBRANE (also referred to a SEROSA) is one of the thin membranes that COVER the walls AND organs in the thoracic & abdominopelvic cavities.
  • The PARIETAL layer of this SEROUS membrane LINE the WALLS of the these cavities.
  • The VISCERAL layer of the SEROUS membrane COVERS the ORGANS (the viscera)
  • BETWEEN the PARIETAL & VISCERAL layers is a very thin, FLUID-FILLED SPACE (CAVITY)

Serous Membranes - 3 Serous Cavities

  1. PLEURA
    • The SEROUS membrane that surrounds the LUNGS in the PLEURA cavity.
  2. PERICARDIUM
    • The SEROUS membrane that surrounds the HEART in the PERICARDIAL cavity.
  3. PERITONEUM
    • The SEROUS membrane that surrounds several ORGANS in the ABDOMINOPELVIC cavity.