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Chapter 1

Introduction to Anatomy & Physiology


Overview of Anatomy and Physiology

•      Anatomy – the study of the structure of body parts and their relationships to one another

•    Gross or macroscopic

•    Microscopic

•    Developmental

•      Physiology – the study of the function of the body’s structural machinery

Gross Anatomy

•      Regional – all structures in one part of the body
(such as the abdomen or leg)

•      Systemic – gross anatomy of the body studied by system

•      Surface – study of internal structures as they relate to the overlying skin

Microscopic Anatomy

•      Cytology – study of the cell

•      Histology – study of tissues

Developmental Anatomy

•      Embryology – study of developmental changes of the body before birth


•      Considers the operation of specific organ systems

•    Renal – kidney function

•    Neurophysiology – workings of the nervous system

•    Cardiovascular – operation of the heart and blood vessels

•      Focuses on the functions of the body, often at the cellular or molecular level


•      Understanding physiology also requires a knowledge of physics, which explains electrical currents, blood pressure, and the way muscle uses bone for movement

Principle of Complementarity

•      Function always reflects structure

•      What a structure can do depends on its specific form

Levels of Structural Organization

•      Chemical – atoms combined to form molecules

•      Cellular – cells are made of molecules

•      Tissue – consists of similar types of cells

•      Organ – made up of different types of tissues

•      Organ system – consists of different organs that work closely together

•      Organismal – made up of the organ systems

Organ Systems of the Body

•      Integumentary system

•    Forms the external body covering

•    Composed of the skin, sweat glands, oil glands, hair, and nails

•    Protects deep tissues from injury and synthesizes vitamin D

Organ Systems of the Body

•      Skeletal system

•    Composed of bone, cartilage, and ligaments

•    Protects and supports body organs

•    Provides the framework for muscles

•    Site of blood cell formation

•    Stores minerals

Organ Systems of the Body

•      Muscular system

•    Composed of muscles and tendons

•    Allows manipulation of the environment, locomotion, and facial expression

•    Maintains posture

•    Produces heat

Organ Systems of the Body

•      Nervous system

•    Composed of the brain, spinal column, and nerves

•    Is the fast-acting control system of the body

•    Responds to stimuli by activating muscles and glands

Organ Systems of the Body

•      Cardiovascular system

•    Composed of the heart and blood vessels

•    The heart pumps blood

•    The blood vessels transport blood throughout the body

Organ Systems of the Body

•      Lymphatic system

•    Composed of red bone marrow, thymus, spleen, lymph nodes, and lymphatic vessels

•    Picks up fluid leaked from blood vessels and returns it to blood

•    Disposes of debris in the lymphatic stream

•    Houses white blood cells involved with immunity

Organ Systems of the Body

•      Respiratory system

•    Composed of the nasal cavity, pharynx, trachea, bronchi, and lungs

•    Keeps blood supplied with oxygen and removes carbon dioxide

Organ Systems of the Body

•      Digestive system

•    Composed of the oral cavity, esophagus, stomach, small intestine, large intestine, rectum, anus, and liver

•    Breaks down food into absorbable units that enter the blood

•    Eliminates indigestible foodstuffs as feces

Organ Systems of the Body

•      Urinary system

•    Composed of kidneys, ureters, urinary bladder, and urethra

•    Eliminates nitrogenous wastes from the body

•    Regulates water, electrolyte, and pH balance of the blood

Organ Systems of the Body

•      Male reproductive system

•    Composed of prostate gland, penis, testes, scrotum, and ductus deferens

•    Main function is the production of offspring

•    Testes produce sperm and male sex hormones

•    Ducts and glands deliver sperm to the female reproductive tract

Organ Systems of the Body

•      Female reproductive system

•    Composed of mammary glands, ovaries, uterine tubes, uterus, and vagina

•    Main function is the production of offspring

•    Ovaries produce eggs and female sex hormones

•    Remaining structures serve as sites for fertilization and development of the fetus

•    Mammary glands produce milk to nourish the newborn

Organ System Interrelationships

•      The integumentary system protects the body from the external environment

•      Digestive and respiratory systems, in contact with the external environment, take in nutrients and oxygen

Organ System Interrelationships

•      Nutrients and oxygen are distributed by the blood

•      Metabolic wastes are eliminated by the urinary and respiratory systems 

Necessary Life Functions I

•      Maintaining boundaries – the internal environment remains distinct from the external

•    Cellular level – accomplished by plasma membranes

•    Organismal level – accomplished by the skin

•      Movement – locomotion, propulsion (peristalsis), and contractility

•      Responsiveness – ability to sense changes in the environment and respond to them

•      Digestion – breakdown of ingested foodstuff

Necessary Life Functions II

•      Metabolism – all the chemical reactions that occur in the body

•      Excretion – removal of wastes from the body

•      Reproduction – cellular and organismal levels

•    Cellular – an original cell divides and produces two identical daughter cells

•    Organismal – sperm and egg unite to make a whole new person

•      Growth – increase in size of a body part or of the organism

Survival Needs

•      Nutrients – chemical substances used for energy and cell building

•      Oxygen – needed for metabolic reactions

•      Water – provides the necessary environment for chemical reactions

•      Maintaining normal body temperature – necessary for chemical reactions to occur at life-sustaining rates

•      Atmospheric pressure – required for proper breathing and gas exchange in the lungs


•      Homeostasis is the ability to maintain a relatively stable internal environment in an ever-changing outside world

•      The internal environment of the body is in a dynamic state of equilibrium

•      Chemical, thermal, and neural factors interact to maintain homeostasis

Homeostatic Control Mechanisms

•      Variable produces a change in the body

•      Receptor monitors the environments and responds to changes (stimuli)

•      Control center determines the set point at which the variable is maintained

•      Effector provides the means to respond to the stimulus

Homeostatic Control Mechanisms

Negative Feedback

•      In negative feedback systems, the output shuts off the original stimulus

•      Example:  Regulation of blood glucose levels

Positive Feedback

•      In positive feedback systems, the output enhances or exaggerates the original stimulus

•      Example:  Regulation of blood clotting

Homeostatic Imbalance

•      Disturbance of homeostasis or the body’s normal equilibrium caused by disease

•      Overwhelming of negative feedback mechanisms allowing destructive positive feedback mechanisms to take over

Anatomical Position

•      Body erect, feet slightly apart, palms facing forward, thumbs point away from the body

Directional Terms

•      Superior and inferior – toward and away from the head, respectively

•      Anterior and posterior – toward the front and back of the body

•      Medial, lateral, and intermediate – toward the midline, away from the midline, and between a more medial and lateral structure

•      Proximal and distal – closer to and farther from the origin of the body

•      Superficial and deep – toward and away from the body surface

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Regional Terms

•      Axial – head, neck, and trunk

•      Appendicular – appendages or limbs

•      Specific regional terminology

Body Planes

•      Sagittal and medial – divides the body into right and left parts

•      Midsagittal – sagittal plane that lies on the midline

•      Frontal or coronal – divides the body into anterior and posterior parts

•      Transverse or horizontal (cross section) – divides the body into superior and inferior parts

•      Oblique section – cuts made diagonally

Body Cavities

•      Dorsal cavity protects the nervous system, and is divided into two subdivisions

•    Cranial cavity is within the skull and encases the brain

•    Vertebral cavity runs within the vertebral column and encases the spinal cord

•      Ventral cavity houses the internal organs (viscera), and is divided into two subdivisions: thoracic and abdominopelvic

Body Cavities

•      Thoracic cavity is subdivided into pleural cavities, the mediastinum, and the pericardial cavity

•    Pleural cavities – each houses a lung

•    Mediastinum – contains the pericardial cavity, and surrounds the remaining thoracic organs

•    Pericardial – encloses the heart

•      The abdominopelvic cavity is separated from the superior thoracic cavity by the dome-shaped diaphragm

•      It is composed of two subdivisions

•    Abdominal cavity – contains the stomach, intestines, spleen, liver, and other organs

•    Pelvic cavity – lies within the pelvis and contains the bladder, reproductive organs, and rectum

Ventral Body Cavity Membranes

•      Parietal serosa covering the body walls

•      Visceral serosa covering the internal organs

•      Serous fluid separates the serosae

Other Body Cavities

•      Oral and digestive – mouth and cavities of the digestive organs

•      Nasal –located within and posterior to the nose

•      Orbital – house the eyes

•      Middle ear – contain bones (ossicles) that transmit sound vibrations

•      Synovial – joint cavities

Abdominopelvic Regions

•      Umbilical

•      Epigastric

•      Hypogastric

•      Right and left iliac or inguinal

•      Right and left lumbar

•      Right and left hypochondriac

Abdominopelvic Quadrants

•      Right upper

•      Left upper

•      Right lower

•      Left lower