Ch 1: Study of Body Functions

• Physiology:

  • Greek origin
  • Studying the nature of bodies
  • taking quantitative measurements and comparing them to the normal ranges we know
• Animal models are the first tested to study the effects of new drugs. Normally years long for safety and efficacy.
• Phase I: testing the drug on healthy humans.

  Phase II: add in some with the disease of interest.

  Phase III: add in a lot of people, covering all genders and ethnic groups. Also some with additional diseases.

  FDA Approval.

  Phase IV: looks for additional uses of the drug.
• Viagra was originally used to treat high blood pressure. Then they discovered that it was better used for erectile disfunction.
• Erasistratus: first physiologist. Tried to apply some physical laws to the human body.
• Galen: most prominent physiologist of his time.
• Harvey: showed that the heart pumps the blood through a closed system.
• Bernard: internal environment maintains fairly constant conditions, even though external conditions are changing.
• Cannon: coined the term "homeostasis".
• Landsteiner: different blood types.
• Adolf von Behring: coined the term "antibody"
• Pavlov: physiology of digestion.
• Langley: autonomic nervous system
• Banting, Best, Macleod: insulin
• Gyorgyi: role of ATP
• Crick, Watson, Frankling: structure of DNA
• Homeostasis: the basis for normalcy. If this deviates, we end up in a negative feedback loop in order to help adjust.
• Negative Feedback Loop:

  1. Stimulus: change from the norm
  2. Sensor: alerted by the stimulus and sends a message
  3. Integrating Center: performs an additional check to look for changes from the set point.
  4. Effectors: perform the change
• Positive Feedback Loops: cause reaction in the same direction of the stimulus.
• Maintaining Homeostasis:

  • Intrinsic: built into the organs being regulated
  • Extrinsic: regulated by the nervous and endocrine systems
• Histology: the microscopic study of anatomy, tissues, and cells.
• Organs: the anatomical and functional units of the body.

  Systems: organs arranged together by function.
• 4 Main Types of Tissue: muscle, nervous, epithelial, connective
• Skeletal Muscle:

  • voluntary, striated, multinucleated, attaches to tendons
  • movement and support
• Cardiac Muscle:

  • involuntary, striated, one nucleus, branched
  • intercalated discs= cells connect
  • electrical and mechanical
• Smooth Muscle:

  • involuntary, non striated, one nucleus,
  • line the digestive tract, blood vessels, and ducts.
• Vasoconstriction: less blood flow, muscle contracts

  Vasodilation: more blood flow, muscle relaxes
• Nervous Tissue:

  • neuralgia cells -> structural support
  • Neuron:
  • Axon: lined with myelin sheath
  • Dendrite: receive incoming messages
  • Cell Body: metabolic center
• Epithelial Tissue:

  • form membranes and line hollow surfaces.
• Exocrine Glands = ducts

  Endocrine Glands = no ducts
• Shape of Cells in Uppermost layer:

  • squamous: squished
  • cuboidal: cubes
  • columnar: greater height than width
• Number of Layers of Tissue:

  • 1 layer: simple
  • 2 layers: stratified
  • appears to be greater than 1: pseudo stratified
• The stomach lining is replaced every 2-3 days.

  The skin is replaced every 2 weeks.
• Exocrine Glands:

  • have ducts= openings to some surface of the body.
  • myoepithelial cells line the gland. smooth muscle, contracts the squeeze of the gland.
• Sebaceous Glands:

  • secrete sebum, used to waterproof your cells
  • found in mammals on surfaces with hair
• Sweat Glands:

  • Eccrine: "Merocrine" most common, cover the entire body, thermoregulation
  • Apocrine: axillae and pubic regions, secrete a protein-rich fluid used to feed bacterial colonies.
• Digestive System glands:

  • mucus, salivary, and tubular glands from intestines, liver, and pancreas.
  • liver -> bile to emulsify fats
  • pancreas -> pancreatic juice
• Connective Tissue Proper:
• Connective Tissue Proper:

  • Loose/ Alveolar: collagen scattered about a gel-like substance. Ex: fat
  • Dense Regular: densely packed together in parallel lines. Ex: tendons
  • Dense Irregular: densely packed but in an uncoordinated way. Ex: around organs
• Connective Tissue:

  1. Connective Tissue Proper
  2. Blood
  3. Bone
  4. Cartilage