Lecture 1: Homeostasis Flashcards
Anatomy
Form of the Body
Physiology
Function of the Body
1600 B.C. Ancient Egypt
Some understanding of anatomy (from mummification process) but no understanding of physiology
480-200 B.C. Ancient Greece
Connecting animal dissections to humans to find similarities
Who did animal dissections and created the scientific method?
Alcmaeon
Hippocrates
Aristotle
Herophilos
First Anatomist,
Did live human dissections
158-200 AD Ancient Greece
Not much understanding of function at this time
Galen
Chief physician to the Gladiators,
Observed internal human anatomy through wound inspections,
Dissection of apes and pigs (applied it to humans)
Work stood until 1500s
Leonardo da Vinci
1489
Italy
Drew pictures based on the cadavers, studied skeleton and movements
Andreas Vesalius
1500s
Belgium to Italy
Dissected criminals after their hanging,
Drew more detailed pictures
Mid 1500s-1700s
Explosion in anatomy and physiology studies,
Anatomical theaters became popular
The Atomic Level
Bodies are mostly C, H, O, and N,
Comprised of 60 other elements,
Nucleosynthesis
Elements formed inside stars/supernovae
The Chemical Level
Atoms/molecules, Elements (C, N, O, H), A.A.-Proteins, Fats, Carbs, Not alive
The Cellular Level
Smallest Unit of Life,
Avg cells in body: 75 trillion
The Tissue Level
Groups of cells,
Skin, muscle, etc
The Organ Level
Groups of tissues,
Liver, kidney, heart, etc.
The Organ System Level
Groups of organs,
Digestive system, respiratory system, etc
The Organism Level
Several organ systems,
Skeletal, nervous, etc
Homeostasis
Constant internal environment,
Everything ‘stays the same’,
Factors of homeostasis that respond to external/internal changes (homeostatic regulation)
Body temp, Fluid balance, pH, Electrolyte balance, Dissolved O2 levels, Blood pressure, etc
Dynamic Equilibrium
Fluctuation within a “range” of acceptable normal around a set point
Ex: variation in a person’s body temp
Homeostatic Regulation
Occurs at both the cellular/tissue level and organism level,
Restores homeostasis,
Ex: sunburn is a cellular local change to heal burn
Autoregulation
Intrinsic
Automatic response in a cell, tissue, or organ to some environmental change
Extrinsic Regulation
Responses controlled by nervous and endocrine systems
Receptor
Tells the body you’re shifting away from homeostasis,
Receives the stimulus from PNS,
Control Center
Processes the signal and sends instructions to the CNS (central nervous system; brain, spinal cord, etc),
Determines what action should be taken based on info from receptors
Effector
Carries out instructions through nerves or hormones (muscle will expand or contract, gland tissues will secret or not)
Human Thermoregulation
Blood temp sensing nerve cells relay info to the brain and effect skeletal muscles or sweat glands/smooth muscle to control body temp
Vasodilation
More blood closer to skin
Vasoconstriction
More blood stays closer to organs, signals to brain causes shivering
Negative Feedback Loop
More common,
Minimize the change away from normal,
Shuts down when the effectors start working and the stimulus to receptors decreases,
Ex: temp regulation
Positive Feedback Loop
Uncommon,
Occur in dangerous/stressful situations,
Increase change away from normal,
Response becomes more and more intense until a negative feedback signal shuts it off,
Ex: uterine contractions in childbirth and blood clotting in wounds
