Secondary

• Homeostasis - the maintenance via negative feedback (process), by an organism, of a relatively stable internal physiological environment
  • homeo - same; stasis - static
• e.g. 1: body temperature: 36-38 Celsius, there's a homeostatic range (optimal), 42 Celsius in fever can cause permanent brain damage; hyperthermia, the brain pools away from the brain which in turn doesn't get enough oxygen
  • opposite: microwave on and off - immediate, spontaneous change
  • more like: oven, pre-heat, temperature fluctuate, re
  • positive feedback has nothing to do with homeostasis
• e.g. 2: Blood glucose: 4-6 mmol/L
  • Insulin - produced in pancreas; convert glucose to glycogen (a storage form of glucose) = bank glucose like a pay cheque or lower blood glucose level; in effect if blood glucose too high
    • too much insulin causing diabetes intolerance or diabetes
    • Diabetes inhibits (salt diabetes)
    • Diabetes Mellitus Type I - no insulin
    • Diabetes Mellitus Type II - insulin resistant (made but the body ignores)
      • Gestational diabetes - dangerous for pregnancy, feeding secondary organism
    • too much insulin causes insulin shock, carb loading (nutritional strategy to increase the glycogen stored in the body) will increase to type 2 DM, potential loss of finger and toes, risk of heart attacks, kidneys
  • Glycemic index - how fast food break down into simple sugar like glucose; tomato's high
  • Glucagon - raise the blood glucose to pay off the "debt"
    • fasting - how long to deplete glycogen? muscle 2h at 70% aerobic max, then liver glycogen might be 24h
    • bonk
  • Antagonists
    • Insulin and glucagon
    • PTH vs Calcitonin = Ca
  • ANP vs Aldosterone (renin) = Na
    • drinking salty water causing hypertonic: salty water draw water from the body, considered positive feedback
      • osmolarity
• e.g. 3: Body pH - require memorization
  • Stomach - 1-2 when actively digesting, the rest of time around 5
  • Mouth - 7 depending on water, BC more acidic, East more alkaline (require more detergent, and water softener used to remove Ca and Mg from hard water and replace with Na)
  • Small intestine - 8 (a range of 6-8-7)
  • Blood - 7.38 - 7.4
    • Acidosis - 7.35, more likely to occur than Alkalosis - 7.45
  • Large intestine is acidic
  • note: decreasing pH, more acidic, increasing pH, more alkaline
  • muscle fatigue not actually caused by but can be measured by the lactic acid
• heart rate and blood pressure won't be homeostatic examples
  • BP120/80 mmHg, 135/85 mmHg
  • women higher heart rate
• Organism - alive, living
• Negative Feedback - a homeostatic control mechanism whereby an increase in some substance or activity inhibits the process leading to the increase
  • most of body's homeostatic systems reply on to resist change by sensing a stimulus and counteract the impending change
  • Negating extremes, to limit, remit, & prevent, and maintain homeostasis
  • event A - B (action) - C (response); event A - B1 - B2 - C
    • response negate the action, and cross off it until action no longer required
    • sweating in hot summer
    • satiety and hunger
  • too cold - TSH increases - thyroxin (regulate oxidative metabolism like body's gas pedal, which in turn raise metabolic activity and increase the body temp, and then shut it off when done)
    • body actually always produce thyroxin, sometime more or less, 7/24
    • Metabolism - any chemical reaction within a cell, tend to produce heat as byproduct
    • eating not so energy-dense food in summer
• Positive Feedback usually adds to the rate at which a change is occurring which does not maintain a steady state.
  • e.g.: reproductive system - estrogen release during pregnancy until plateau and then system resets normal
    • for the extreme muscular work of labor and delivery during childbirth are a result of a positive feedback system
  • bring about rapid change
  • Promote, enhance, encourage & makes more change, the opposite of the homeostasis until plateau
  • not homeostatic

Undergraduate

• Homeostasis, the state of relative stability of the body's internal environment
• Disruptions to homeostasis often set in motion corrective cycles aka feedback systems to help restore the conditions needed for health and life
  • pH
  • temperature
• Important aspects
  • Maintaining the proper assortment and quantity of thousands of different chemicals in the body
  • Monitoring the interactions of these chemicals with one another
• cells carry out multiple functions that help each system contribute to the homeostasis of the entire body, while sharing key structures and functions supporting their intense activities.
• The 4 types of tissues in the human body contribute to homeostasis by providing diverse functions including protection, support, communication among cells, and resistance to disease, etc.
• The Integumentary System contributes to homeostasis by protecting the body and helping regulate body temperature, allowing humans to sense pleasurable, painful, and other stimuli in the external environment.
• Bone tissue is continuously growing, remodeling, and repairing itself, contributing to homeostasis of the body by providing support and protection, producing blood cells, and storing minerals and triglycerides.
• The bones of the Axial skeleton contributes to the homeostasis by protecting many of the body's organs like the brain, spinal cord, heart, and lungs, important in support and calcium storage and release
• The bones of the Appendicular skeleton contributes to homeostasis by providing attachment points and leverage for muscles, aiding body moments; by providing support and protection of internal organs, e.g. the reproductive organs; by storing and releasing calcium
• Joints of the skeletal system contribute to homeostasis by holding bones together in ways that allow for movement and flexibility
• Muscular Tissue contributes to homeostasis by producing body movements, moving substances thru the body, and producing heat to maintain normal body temperature
• Muscular System and Muscular Tissue of the body contribute to homeostasis by stabilizing body position, producing movements, regulating organ volume, moving substances within the body, and producing heat.
• The excitable characteristic of Nervous Tissue allows for the generation of Nerve Impulses that provide communication with and regulation of most body organs
• The Spinal Cord and Spinal Nerves contribute to homeostasis by providing quick, reflexive responses to many stimuli. Spinal cord is the pathway for sensory input to the brain and motor output from the brain.
• The Brain contributes to homeostasis by receiving sensory input, integrating new and stored information, making decisions, and executing responses thru motor activities.
• The ANS contributes to homeostasis by conveying motor output from the central nervous system to smooth muscle, cardiac muscle, and glands for appropriate responses to integrated sensory information
• The sensory and motor pathways of the body provide routes for input into the brain and spinal cord and for output to targeted organs for responses like muscle contraction
• Sensory organs have special receptors allowing us to smell, taste, see, hear, and maintain equilibrium or balance. Information conveyed from these receptors to the central nervous system is used to help maintain homeostasis
• The hormones of the Endocrine System contribute to homeostasis by regulating the activity and growth of target cells in the body. Hormones also regulate metabolism
• blood contributes to homeostasis by transporting oxygen, carbon dioxide, nutrients, and hormones to and from your body's cells. It also helps regulate body pH and temperature, and provides protection against disease thru phagocytosis and the production of antibodies.
• The heart contributes to homeostasis by pumping blood thru blood vessels to the tissues of the body to deliver oxygen and nutrients and remove wastes
• Blood vessels contribute to homeostasis by providing the structures for the flow of blood to and from the heart and the exchange of nutrients and wastes in tissues, also important in adjusting the velocity and volume of blood flow
• The lymphatic system contributes to homeostasis by draining interstitial fluid and also providing the mechanisms for defense against disease.
• The Respiratory System contributes to homeostasis by providing for the exchange of gases (oxygen and carbon dioxide) b/w the atmospheric air, blood, and tissue cells. It also helps adjust the pH of body fluids.
• The Digestive System contributes to homeostasis by breaking down food into forms that can be absorbed and used by body cells. It also absorbs water, vitamins, and minerals; eliminates wastes from the body
• Metabolic reactions contribute to homeostasis by harvesting chemical energy from consumed nutrients for use in the body's growth, repair, and normal functioning
• The Urinary System contributes to homeostasis by excreting wastes; altering blood composition, pH, volume, and pressure; maintaining blood osmolarity; and producing hormones
• Regulating the volume and composition of body fluids, controlling their distribution throughout the body, and balancing the pH of body fluids are crucial to maintaining overall homeostasis and health
• The male and female reproductive organs work together to produce offspring. The female reproductive organs contribute to sustaining the growth of embryos and fetuses
• Both the genetic material inherited from parents (heredity) and normal development in the uterus (environment) play important roles in determining the homeostasis of a developing embryo and fetus and the subsequent birth of a healthy child.

Reflection

• negative feedback, toilet: float / ring, flush the toilet, what happens; what happen if you pour the water?
• Positive Feedback - ice cream or like chips with high carb content, half a potatoes chip, and half a tiny teaspoon of ice cream - surge in insulin, and feel urge to eat more
• Homeostasis is ultimately controlled by nervous and endocrine system
  • hormone: chemical messenger
• White blood cells increase the antigen during an allergic reaction - not homeostatic
  • increased physical activity increases heart rate in humans - maintain oxygen supply
• Living organism vs inanimate - maintain homeostasis, respond to environmental stimuli, composed of one or more cells, possess molecules of DNA
• Mechanism - emptying bladder, light entering the eye
• Endoplasmic reticulum is the internal highway of transport within a cell; mitochondria - powerhouse
• Reproductive system not essential to homeostasis due to the positive feedback
• why negative feedback involves 3 actors