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Pathophysiology: how physiological processes are altered in disease or injury
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Animal Physiology Dr. Kashif Asghar
Pathophysiology: how physiological processes are altered in disease
or injury Physiology How Organism function Levels of organization
of human body Chemical and Molecular Level
Molecular composition of the human body Water 67% Proteins 20%
Carbohydrates 3% Lipids 10% Elemental composition Hydrogen 62%
Oxygen 26% Carbon Nitrogen 1.5% Other Elements: Calcium Phosphorus
Potassium Sodium Sulfur Chlorine Magnesium Iron Iodine Trace
elements 0.2% 0.06% 0.05% 0.04% 0.03% 0.0005% % (see caption)
Levels of Organization: Cellular
Basic units of structure and function Levels of Organization:
Tissue
Epithelial tissue Connective tissue Muscle tissueNervous tissue
Cells with similar functions grouped into the 4 primary tissues
SkinThe Largest Organ
Outer layer of protective cornified epidermis Next layer the dermis
contains connective tissue, glands, blood vessels (BVs), nerves
Inner layer the hypodermis contains adipose tissue, BVs, nerves
Stem Cells Most cells in organs are highly specialized or
differentiated Many organs retain small populations of adult stem
cells less differentiated so can become many cell types
Example:bone marrow stem cells can give rise to all of the
different blood cell types Body-Fluid Compartments
Our body has both intracellular and extracellular compartments:
Intracellular - inside cells (cytoplasm) Extracellular - outside
cells (blood plasma, interstitial fluid) Compartments separated by
the cells plasma membrane Levels of Organization: Organ
System
Chemical or Molecular Levels Atoms in combination Complex protein
molecules Protein filaments Organ System Level The heart Cellular
Level Heart muscle cell Tissue Level Cardiac muscle tissue Organ
Level Cardiovascular Reproductive Urinary Digestive Respiratory
Lymphoid Endocrine Nervous Muscular Skeletal Integumentary Organism
Levels of Organization: Organ System
Organ System Level Cardiovascular Reproductive Urinary Digestive
Respiratory Lymphoid Endocrine Nervous Muscular Skeletal
Integumentary Organism Level Organs located in different regions of
the body that perform related functions are grouped into systems
Organismal Level Chemical level Atoms combine to form
molecules.
Cellular level Cells are made up of molecules. Tissue level Tissues
consist of similar types of cells Organ level Organs are made up of
different types of tissues. Organ system level Organ systems
consist of different organs that work together closely. Organismal
level The human organism is made up of many organ systems.
Cardiovascular system Organelle Molecule Atoms Smooth muscle cell
Smooth muscle tissue Connective tissue Blood vessel (organ) Heart
Blood vessels Epithelial tissue 1 2 3 4 5 6 History of Physiology
Arist (384 322 BCE) speculated on body function Erasistratus (304
-~250 BCE) considered the father of physiology - applied physical
laws to the study of human function Galen ( A.D.) -believed the
working body was not understandable without knowledge of its
structure William Harvey (15781657)-blood pumped in a closed system
of vessels Claude Bernard (1813 1878) internal environment remains
constant despite everchanging external environment Walter Cannon
(1871 1945) coined the term homeostasis Introduction to basic
concepts of physiology
Scientific Method Levels of Organization Homeostasis - Feedback
loops Homeostasis Our organ systems work together to maintain
homeostasis despite constant challenges Homeostasis Maintenance of
a state of dynamic constancy
internal conditions are stabilized above and below a physiological
set pointby negative feedback loops Homeostasis and Negative
Feedback Loops
All physiological parameters have a set point X Sensor:Detects
deviation from set point Integrating center:Determines response
Effector:Produces response to re-establish X Homeostasis Negative
feedback loops body temperature, blood sugar, blood pressure
Example:control of body temperature Set point:37 C
Sensor:Temperature receptors Integrating center:Brain
Effector:sweat glands/muscles Control of blood glucose level
(Insulin & Glucagon) Homeostasis: Negative Feedback
Example: control of blood sugar Set point: 5 mmol/L Sensor:
pancreatic cells Integration: Endocrine system Effector: insulin
and glucagon Homeostasis: Negative Feedback
Example: control of blood pressure Set point: normal blood pressure
Sensor: barorecptors Integration Center: brain Effector: heart /
arteries Homeostasis and Positive Feedback
Does not maintain homeostasis and is rare Occurs when the body
needs to amplify a process Producing blood clots Creates the LH
surge that causes ovulation Between the uterus and oxytocin
secretion during childbirth Scientific Method Discovery-based
science - making observations and measurements regarding the
natural world Hypothesis-based science -conduct and analyze
experiments to test a hypothesis 1.develop a testable hypothesis to
answer a scientific question based on natural observations 2.design
and conduct experiments in an objective, unbiased, repeatable
manner 3.analyze data and form conclusions that either support or
deny the hypothesis Discovery-based Science
Is there a difference in resting heart rate between people who
exercise and those who dont? - Measure heart rate in people who
exercise - Measure heart rate in people who dont exercise - Analyze
data and from conclusions Study establishes a correlation
(relationship) between exercise and heart rate but not causation
Hypothesis-based Science
Hypothesis - a tentative answer to a question - an explanation on
trial Scientific Method Hypothesis-based science:
Form hypothesis:question to be answered People who exercise
regularly have lower resting heart rate Treatment group:individuals
subject to the test condition Randomly choose a group who must
exercise (experimental group) Control group:similar individuals not
subjected to treatment Randomly choose a group that is not allowed
to exercise (control) Dependent variable:outcome you are measuring
Heart rate Unbiased:double-blind (placebo) study Random groups
Analyze data and form conclusions Controlled experiment establishes
causation Scientific Method to Develop New Drugs
Biomedical research - test effectiveness & toxicity of a new
drug - first in vitro (tissue culture) then in vivo (animal models)
Clinical trials performed: Phase I Trials:Toxicity and metabolism
tested in healthy human volunteers (no toxic effects observed)
Phase II Trials:Effectiveness and toxicity tested in target
population (effective with minimal toxicity) Phase III
Trials:Widespread test of drug in diverse population (gender,
ethnicity, other health problems) Phase IV Trials:Drug is tested
for other potential uses (sent to FDA for approval) Circulatory
system