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Relationship between Anatomy and Physiology Anatomy
The study of internal and external structures of the body and the physical relationships among body parts
Physiology The study of how living organisms perform their vital
functions
Someone studying anatomy might examine how and where a particular muscle attaches to the skeleton, whereas someone studying physiology might consider how a muscle contracts or what forces a contracting muscle exerts on the skeleton
Relationship between Anatomy and Physiology Anatomical info provides clues about
functions (physiology), and physiological mechanisms can be explained only in terms of the underlying anatomy
ALL SPECIFIC FUNCTIONS ARE PERFORMED BY SPECIFIC STRUCTURES!!!!!
Relationship between Anatomy and Physiology Anatomy can be divided into gross
(macroscopic) anatomy and microscopic anatomy
Gross AnatomyExamination of relatively large structures
○ Usually visible with unaided eye 5 different forms of gross anatomy
Surface anatomy○ Study of general form and superficial markings
Regional anatomy○ Anatomical organization of specific areas of body
(head, neck, trunk)
Relationship between Anatomy and Physiology 5 different forms of gross anatomy (con’t)
Systemic anatomy○ Study of the structure of organ systems (skeletal
system, muscular system, cardiovascular system, etc.)Developmental anatomy
○ Describes the changes in form that occur between conception and physical maturity
○ Embryology – study of early developmental processesClinical anatomy
○ Subspecialities important in clinical practice Medical anatomy (anatomical features that change during
illness) Radiographic anatomy (anatomical structures seen using
imaging techniques)
Relationship between Anatomy and Physiology Microscopic Anatomy
Study of structures that cannot be seen without magnification
Has 2 major divisionsCytology – analysis of the internal structure
of individual cellsHistology – examination of tissues
Relationship between Anatomy and Physiology Physiology
The study of the function of anatomical strucures
Can be divided into 4 major specialtiesCell physiology – study of the function of cells
○ Chemical processes within cells and chemical interactions between cells
Special physiology – study of the physiology of specific organs
Systemic physiology – study of the functioning of specific organ systems
Pathological physiology – study of the effects of diseases on organ or system fuctions
Levels of Organization The Chemical (or Molecular) Level
Atoms can combine to form molecules with complex shapes
The functional properties of a particular molecule are determined by its unique 3D shape
The Cellular LevelMolecules interact to form organelles, each of which
has specific functions.Organelles are grouped to form cells
The Tissue LevelGroups of cells working together to perform specific
functions○ Heart muscle cells interact with other types of cells and
extracellular materials to form cardiac muscle tissue
Levels of Organization The Organ Level
Two or more tissues working in combination to perform several functions○ Cardiac muscle tissue, in combination with
connective tissue from the bulk of the heart. The Organ System Level
Two or more organs interacting○ The heart and blood vessels work together to form
the cardiovascular system. The Organism Level
Highest level of organizationAll organ systems working together
Homeostasis
One of the roles of the organ systems in an organism is to maintain homeostasis.
Homeostasis – maintaining a stable internal environment.Absolutely vital to survival
Homeostatic regulation – adjustment of physiological systems to preserve homeostasis.
Homeostasis
2 mechanisms of homeostasisAutoregulation (intrinsic regulation) – when
a cell, tissue, organ or organ system adjusts its activities automatically in response to an environmental change○ Ex: when blood oxygen levels decrease in a
tissue, the cells release a chemical that dilate local blood vessels. This increases blood flow and, therefore, oxygen.
Homeostasis
2 mechanisms of homeostasis (con’t)Extrinsic regulation – from activities of the
nervous and/or endocrine systems.○ Ex: During exercise, your nervous system
increases heart rate so that blood will circulate faster. Will also decrease blood flow to less active organs.
Homeostasis
The nervous system directs rapid, short-term, and very specific responsesResponse to placing hand on a hot stove
Endocrine system releases hormones that affect tissues and organs throughout the body.Not immediate, not specific, may be long-
term
Homeostasis
Homeostatic regulatory mechanism consists of 3 partsReceptor – sensor that is sensitive to a
particular change in environmentControl center – receives and processes
info from receptor and sends out commandsEffector – cell or organ that responds to the
commands from control center.
Similar to thermostat in your house
Homeostasis Negative feedback
Most regulatory mechanisms involve this opposition to changing conditions
Example is body temperature control (thermoregulation)○ Control center is the hypothalamus region of the brain○ Hypothalamus receives info from two receptors: skin
receptors and one in hypothalamus○ Normal body temp is 98.6o. If temp increases, the
control center targets two effectors: muscles in the walls of the blood vessels supplying the skinsweat glands
Homeostasis Negative feedback (con’t)
The muscles in the skin blood vessels relax, increasing blood flow to skin.
Sweat glands increase their secretionThe skin acts like a radiator by losing heat to the
environment○ Evaporation of sweat speed the process
As temp returns to normal, temp at hypothalamus declines, and the control center becomes less active
Blood flow and sweat production return to normal.
Homeostasis
There are variations in normal homeostatic levels between individuals95% of population has body temp between
36.7oC and 37.2oCPhysicians must keep this in mind when
treating patients.
Homeostasis Positive feedback
Produces a response that enhances the change in the original conditions.
Usually produces extreme responsesWhat if your thermostat was connected to your
heater instead of your air conditioner?○ What would occur if the temp in your house increased?
When temp exceeds set point, thermostat would turn on the heater, and it would continue to run until someone turned off the thermostat, heater, or intervened in some other way.
This escalating cycle is called a positive feedback loop
Homeostasis Positive feedback (con’t)
In your body, these loops are found when a potentially dangerous process must be completed quickly before homeostasis can be restored.○ Ex: immediate danger from a severe cut will
decrease blood pressure and reduce efficiency of the heart
○ The response is to clot the blood.○ Each step in the process accelerates the process
until a clot is formed Labor and delivery of a baby is another
example
Frames of Reference for Anatomical Studies Early anatomists faced communication
problems.A “bump on the back” doesn’t give very
precise info about its location
Prominent anatomical structures serve as landmarks, distances are measured in centimeters, and specialized directional terms are used
Frames of Reference for Anatomical Studies Superficial Anatomy
Anatomical landmarks are used in reference to the anatomical position○ Anatomical position – hands at side, palms
facing forward, and feet together○ Descriptions given are in reference to the
anatomical position, unless otherwise notedProne – lying face down in the anatomical
positionSupine – lying face up in the anatomical
position
Frames of Reference for Anatomical Studies Anatomical Regions
Abdominopelvic quadrants○ Formed by a pair of lines that intersect at the
umbilicus (naval)○ Used by physicians to help determine possible
cause of aches, pains, injuries.○ Internal organs can be found in different
quadrantsAbdomiopelvic regions
○ More specific than quadrants○ Preferred by anatomists
Frames of Reference for Anatomical Studies Anatomical Directions
The terms left and light always refer to the left and right sides of the subject, NOT of the observer
Frames of Reference for Anatomical Studies Sectional Anatomy
Sometimes the best way to understand anatomy is to slice through it and look at the internal organization
Useful with imaging techniquesRadiologists use these when looking at films
Frames of Reference for Anatomical Studies Planes and Sections
Transverse plane – right angle to long axis of object, dividing it into superior and inferior○ A cut in this plane is called a transverse section
Frontal plane – parallel to long axis; extends from side to side, dividing the body into anterior and posterior○ A cut in this plane is called a frontal section
Sagittal plane – parallel to long axis; extends from front to back, dividing the body in to left and right○ A cut down the midline is called a midsagittal section○ Parallel cuts are called parasagittal sections
Frames of Reference for Anatomical Studies Body cavities
Internal chambers where many vital organs can be found
2 functions○ Protect organs○ Permit change of size and shape of the organs
Your diaphragm divides your torso into two cavities○ Thoracic cavity○ Abdominopelvic cavity
Viscera – organs enclosed (fully or partially) by these cavities
Frames of Reference for Anatomical Studies Body cavities (con’t)
Thoracic cavity○ Contains lungs and heart, associated organs
of respiratory, cardiovascular, and lymphatic system; lower esophagus; thymus
○ Boundaries are the ribs and diaphragm○ Subdivided into left and right pleural cavities,
which each contain a lung.○ Contains pericardial cavity, which surrounds
the heart
Frames of Reference for Anatomical Studies Body cavities (con’t)
Abdomiopelvic cavity○ Extends from diaphragm to pelvis○ Divided into a superior abdominal cavity and
an inferior pelvic cavity○ The peritoneal cavity surrounds the abdominal
and pelvic cavities
Frames of Reference for Anatomical Studies Body cavities (con’t)
Abdominal cavity contains the liver, stomach, spleen, small intestine, and most of the large intestine○ The kidneys and pancreas lie posteriorly
between the peritoneal cavity and the muscles of the abdominal cavity
The pelvic cavity contains distal large intestine, urinary bladder, and various reproductive organs