Animal Physiology

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Animal Physiology

• Dr. Kashif Asghar
• Email drkashifasghar_at_gmail.com

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• Pathophysiology
• how physiological processes are altered in
  disease or injury

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Physiology
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How Organism function
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Levels of organization of human body
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Chemical and Molecular Level
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Levels of Organization Cellular

• Basic units of structure and function

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Levels of Organization Tissue

• Epithelial tissue Connective tissue
  Muscle tissue Nervous tissue

• Cells with similar functions grouped into the 4
  primary tissues

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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

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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

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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

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Levels of Organization Organ System
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Levels of Organization Organ System

• Organs located in different regions of the body
  that perform related functions are grouped into
  systems

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Organismal Level
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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 (130 -201 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

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Introduction to basic concepts of physiology

• Scientific Method
• Levels of Organization
• Homeostasis
• - Feedback loops

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Homeostasis

• Our organ systems work together to maintain
  homeostasis despite constant challenges

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Homeostasis

• Maintenance of a state of dynamic constancy
• internal conditions are stabilized above and
  below a physiological set point by negative
  feedback loops

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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

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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

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Control of blood glucose level (Insulin
Glucagon)
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Homeostasis Negative Feedback

• Example control of blood sugar
• Set point 5 mmol/L
• Sensor pancreatic cells
• Integration Endocrine system
• Effector insulin and glucagon

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Homeostasis Negative Feedback

• Example control of blood pressure
• Set point normal blood pressure
• Sensor barorecptors
• Integration Center brain
• Effector heart / arteries

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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

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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

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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

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Hypothesis-based Science

• Hypothesis - a tentative answer to a question
• - an explanation on trial

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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

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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)

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Circulatory system