AP Unit 1 - Bio185 A&P1 Homeostasis Chemistry and the Cell...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Bio185 A&P1 – Homeostasis, Chemistry and the Cell Page 1 of 16 Homeostasis Homeostasis = maintenance of a relatively constant (stable) internal body environment Homeostatic regulation = adjustments in physiological systems to preserve homeostasis A. Feedback systems: 1. Components: 1. Receptor – 2. Control center (integration center) – 3. Effector – 2. Two types of feedback systems: a. Negative Feedback — response opposes or reverses the original stimulus e.g. thermoregulation, blood pressure regulation 1. Dynamic equilibrium Set point – Normal range – 2. Action slows and stops as condition returns to normal. 3. Typically regulate conditions that remain fairly stable over long periods b. Positive Feedback — response strengthens or reinforces the stimulus (change in conditions) e.g. Normal childbirth 1. Continues until outside event breaks cycle (event outside of cycle) 2. Typically reinforce conditions that do not happen often 3. Points to Note a. System integration: b. Failure to maintain homeostasis malfunction symptoms = disease Chemistry Matter – A. Atoms = smallest unit of an element
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Bio185 A&P1 – Homeostasis, Chemistry and the Cell Page 2 of 16 1. Contain 3 major types of Subatomic particles: Protons: (+) charge, located in nucleus Neutrons: neutral charge, located in nucleus (see isotopes) Electrons: (-) charge, located in cloud surrounding nucleus; arranged in shells number of electrons in outer electron shell determines chemical properties of that element only outer electrons can react & create bonds with other atoms 2. Isotopes = same element, different number of neutrons e.g. radioactive elements All matter is composed of atoms in various combinations. Their interactions establish the foundations of physiology at the cellular level. B. Chemical Bonds Atoms gain stability by gaining, losing or sharing electron through chemical reactions. (NEVER gain/loss of protons!) 1. Ionic Bonds Ions = Charged atoms — through gain or loss of electrons e.g. sodium chloride 2. Covalent bonds electrons (in outer shells) are shared between two atoms. a. Nonpolar covalent bonds – electrons shared equally between atoms b. Polar covalent bonds electrons tend to spend more time around one atom than the other The slight difference in charge between the two ends of the molecule enable weak attractive forces between neighboring molecules. e.g. H 2 O C. Hydrogen bonds most important of weak attractive force slightly (+) H, attracted to slightly (-) oxygen or nitrogen between molecules (or between parts of a large molecule) e.g. water surface tension, DNA basepairing
Image of page 2
Bio185 A&P1 – Homeostasis, Chemistry and the Cell Page 3 of 16 Compounds Nutrients -- essential elements and molecules obtained from the diet Metabolites -- molecules synthesized or broken down by chemical reactions inside the body.
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern