Physiology -Chap 1- Outline

Chapter 1

Anatomy & Physiology Defined
Anatomy: the science of body structures and the relationships among them
~First studied by dissection: the careful cutting apart of body structures to study their relationships
Physiology: the science of body functions


Subdisciplines of Anatomy
Embryology: Structures that emerge from the time of the fertilized egg through the eight week in utero
Developmental Biology: Structures that emerge from the time of the fertilized egg to the adult form
Histology: Anatomical landmarks on the surface of the body through visualization and palpation
Surface Anatomy: Structures that can be examined without using a microscope
Gross Anatomy: Structure of specific systems of the body such as the nervous or respiratory systems
Systemic Anatomy: Microscopic structure of tissues
Regional Anatomy: Specific regions of the body such as the head or chest
Radiographic Anatomy: Body structures that can be visualized with x-rays
Pathological Anatomy: Structural changes (from gross to microscopic) associated with disease


Subdisciplines of Physiology
Neurophysiology: Functional properties of nerve cells
Endocrinology: Hormones (chemical regulators in the blood) and how they control body functions
Cardiovascular Physiology: Functions of the heart and blood vessels
Immunology: How the body defends itself against disease-causing agents
Respiratory Physiology: Functions of the air passageways and lungs
Renal Physiology: Functions of the kidneys
Exercise Physiology: Changes in cell and organ functions as a result of muscular activity
Pathophysiology: Functional changes associated with disease and aging


Levels of Organization
6 Levels of Organization: chemical, cellular, tissue, organ, system, and organism
Chemical Level: includes 2 or more atoms joined together and molecules
~2 familiar molecules found in the body are: DNA and glucose
Cellular Level: Molecules combine to form cells
~Cells are the smallest living units in the human body
Tissues: groups of cells and the materials surrounding them that work together to perform a particular function
~4 basic types of tissues: epithelial tissue, connective tissue, muscular tissue, and nervous tissue
Organ Level: different types of tissues are joined together
Organs: composed of 2 or more different types of tissues
System level: a.k.a. organ-system level
System: consists of related organs with a common function
Organism: any living individual


Noninvasive Diagnostic Techniques
Noninvasive diagnostic techniques: used by health-care professionals to assess certain aspects of body structure and function
Inspection: the examiner observes the body for any abnormal changes
Palpation: the examiner feels body surfaces with their hands
Auscultation: the examiner listens to body sounds to evaluate the function of certain organs (stethoscopes may be used)
Percussion: the examiner taps on the body surface with the fingertips and listens to the resulting echo
~May reveal the abnormal presence of fluid in the lungs or in the intestines
~Provides info about the size, consistency, and position of an underlying structure


Basic Life Processes
Metabolism: the sum of all the chemical processes that occur in the body
~Catabolism: the breakdown of complex chemical substances into simpler components
~Anabolism: the building up of complex chemical substances from smaller, simpler components
Responsiveness: the body’s ability to detect and respond to changes
Movement: motion of the whole body, individual organs, single cells, etc…
Growth: an increase in body size that results from an increase in the size of existing cells, the number of cells, or both
Differentiation: the development of a cell form an unspecialized to a specialized state
Stem Cells: precursor cells which can divide and give rise to cells that undergo differentiation
Reproduction: either the formation of new cells for tissue growth, repair, or replacement, or the production of a new individual


Homeostasis
Homeostasis: the condition of balance in the body’s internal environment due to the ceaseless interplay of the body’s many regulatory processes
~Glucose level in blood normally stays between 70 and 110 milligrams of glucose per 100 milliliters of blood

Body Fluids
Body fluids: dilute, watery solutions containing dissolved chemicals that are found inside cells as well as surrounding them
~Intracellular fluid: fluid within cells
~Extracellular fluid: fluid outside body cells
~Interstitial fluid: the extra-cellular fluid that fills the narrow spaces between cells of tissues
~Blood plasma: extra-cellular fluid within blood vessels
~Lymph: extra-cellular fluid within lymphatic vessels
~Cerebrospinal fluid: extra-cellular fluid in and around the brain and spinal cord
~Synovial fluid: extra-cellular fluid in joints
~Aqueous humor: a.k.a. vitreous body, extra-cellular fluid in the eyes
(Bullet):Because interstitial fluid surrounds all body cells, it is often called the body’s internal environment
~Its composition changes as substances move back and forth between it and blood plasma
Blood Capillaries: the smallest blood vessels in the body

Control of Homeostasis
(Bullet):Homeostasis in the human body is continually being disturbed
~Disruptions come from the external environment and psychological stresses in our social environment
~In most cases the disruption of homeostasis is mild and temporary
~Most often, the nervous system and the endocrine system, working together or independently, provide the needed corrective measures
Nervous System: regulates homeostasis by sending electrical signals known as nerve impulses to organs that can counteract deviations form the balanced state
~Nerve impulses: typically work rapidly through negative feedback systems
Endocrine System: has many glands that secrete messenger molecules called hormones into the blood
~Hormones: typically work slowly through negative feedback systems

Feedback Systems
Feedback System: a.k.a. Feedback Loop, is a cycle of events in which the status of a body condition is monitored, evaluated, changed, re-monitored, reevaluated, and so on
Controlled Condition: each monitored variable (ex: body temp. blood pressure, glucose level, etc…)
Stimulus: any disruption that changes a controlled condition
Receptor: a body structure that monitors changes in a controlled condition and sends input to a control center
~Input is usually in the form of nerve impulses or chemical signals
Control Center: sets the range of values within which a controlled condition should be maintained, evaluates the input it receives from receptors, and generates output commands when needed
~Output is typically nerve impulses, hormones, or other chemical signals
Effector: a body structure that receives output from the control center and produces a response or effect that changes the controlled condition
~Nearly every organ or tissue in the body can behave as an effector
(Bullet): In a feedback system, the response of the system “feeds back” info to change the controlled condition in some way, either negating it (negative feedback) or enhancing it (positive feedback)

Negative Feedback Systems
Negative Feedback System: reverses a change in a controlled condition (ex: blood pressure regulation; negative feedback system)
Baroreceptors: pressure-sensitive nerve cells located in the walls of certain blood vessels, detect the higher pressure

Positive Feedback Systems
Positive Feedback System: tends to strengthen or reinforce a change in one of the body’s controlled conditions
~Operates similarly to a negative feedback system, except that it produces a physiological response that adds to the initial change in the controlled condition (continues until interrupted)
~Ex: normal childbirth, severe blood-loss

Homeostatic Imbalances
(Bullet): Negative feedback systems maintain homeostasis
(Bullet): If one or more components of the body loses their ability to contribute to homeostasis, the normal equilibrium among body processes may be disturbed
(Bullet): If homeostatic imbalance is moderate, a disorder or disease may occur; if it is severe, death may result
Disorder: any abnormality of structure or function
Disease: a specific term for an illness characterized by a recognizable set of signs and symptoms
~Local Disease: affects one part or a limited region of the body
~Systemic Disease: affects either the entire body or several parts of it
Symptoms: subjective changes in body functions that are not apparent to an observer (ex: headache, nausea, anxiety, etc…)
Signs: objective changes that a clinician can observe and measure (ex: swelling, rashes, fever, etc…)
Epidemiology: deals with why, when, and where diseases occur and how they are transmitted
Pharmacology: the science that deals with the effects and uses of drugs in the treatment of disease

Diagnosis of Disease
Diagnosis: the science and skill of distinguishing one disorder or disease from another
~Symptoms, signs, medical history, physical exams, and laboratory tests provide the basis
Medical History: consists of collecting info about events that might be related to a patient’s illness
~Include chief complaint, history of present illness, past medical problems, family medical problems, social history, and a review of symptoms
Physical Examination: an orderly evaluation of the body and its functions
~Includes noninvasive techniques of inspection

Body Positions
Anatomical position: subject stands erect facing the observer; head level and the eyes facing directly forward
Prone Position: A reclining body lying face down
Supine Position: A reclining body lying face up

Regional Names
Principal regions: head, neck, trunk, upper limbs, and lower limbs
Head: consists of the skull and face
Neck: supports the head and attaches it to the trunk
Trunk: consists of the chest, abdomen, and pelvis
Upper Limb: attaches to the trunk and consists of the buttock, thigh, leg, ankle, and foot
Groin: the area on the front surface of the body marked by a crease on each side, where the trunk attaches to the thighs

Directional Terms
Directional Terms: words that describe the position of one body part relative to another
Anterior: front
Posterior: back