BCMB 230 1st EditionExam # 1 Study Guide Lectures: 1 - 7Lecture 1 (Aug 22)Physiology is the study of how the body works. It is often paired with anatomy which, instead of focusing on the functions and processes of the body, focuses on the structure of it. Physiology is split into two studies: it looks at the body at a molecular level (look at protein shape) and it looks at complex processes that depend on the combined functions of many organs of the body.Cells are the simplest structural units for an organism. Cells become specialized to perform certain functions. The four major categories of functions that cells can perform are: muscle cells, neurons, epithelial cells, and connective tissue. Cells with similar properties combine to create tissue. The four general types of tissue are: muscle tissue, nervous tissue, epithelial tissue, and connective tissue. When one type of tissue combines with other types of tissues, it forms an organ. Organs work together to perform an overall function, creating an organ system. An important ability of the body is homeostasis, which is the relatively stable condition of the internal environment of the body (the fluids that surround cells) that results from regulatory system actions. The activities of the cells, tissues, and organs are interrelated and regulated so that any change in the environment of the body creates a reaction to correct the change. Mechanisms that are associated with the idea of homeostasis are feedback systems. The most important one is negative feedback in which the system’s response counteracts the change in the system. During this system there is end product inhibition, which means that the end products reduce the activity of earlier activity (if you have too much of something, stop making it), allowing us to maintain a relatively stable state (ex. temperature). Another feedback system is positive feedback. This is the system in which an initial disturbance sets off a chain of events that then amplifies the disturbance (the process produces something when then goes back to accelerate the process to produce more). Positive feedback is a counter to the principle of homeostasis because it has no obvious means of stopping (therefore, much less common in nature) (ex. blood clotting). The last feedback system is called feed forward which allows the system to anticipate changes; it improves the speed of the body’s homeostatic response and reduces the amount of deviation from the set point, minimizing changes to the body (ex. moving from a warm area to a colder one).Some components of homeostatic control systems to know is the set point (also called the operating point) which is the steady-state value maintained by homeostasis. It is only a predicted value and does not have to be exact. A reflex is a “built-in”, involuntary response to a certain stimulus. This response first starts with a receptor that detects the change and translates the stimulus for the body. The signal goes through the afferent pathway (“to carry to”) to the integrating center (integrator) which is the brain region that compares the value of a variable to a set point. Then the efferent pathway (“to carry away from”) transmits the signal from the integrator to the effector, the cell or cell collection that changes its activity to respond to the change. The receptor usually receives a signal from a chemical messenger or hormone.Homeostatic response can also be local, occurring in the vicinity of a stimulus, without hormones. Reflexes can be endocrine, nervous, or neuroendocrine. If it is extrinsic, it is outside of the system (nerves and hormones). If it is intrinsic, then it is inside of the system. Intrinsic haslocal substances/agents. Paracrine agents are chemical messengers involved in local communication between cells. Autocrine agents are when chemical messengers are secreted bya cell and then acts upon the cell that secreted it.There are several processes that relate to homeostasis. One is adaption which is the change of gene frequency over generations, usually a biological characteristic that favors survival in a particular environment. Another is accommodation which is a change in a physiological process that happens with an individual over a relatively short period. The last oneis acclimatization which is the improved functioning of a homeostatic system that already exists which is usually brought on by a repeated expose to a stimulus. Developed acclimatization is when there is a change in structure or function of one or more organ systems that happens at a critical point (usually fetal level or early childhood) that is potentially irreversibleLecture 2 (Aug 27)An ionic bond is the strong attraction between two oppositely charged ions that leads tothe transfer/exchange of electrons. An ion is an atom that gains or losses one or more electrons which results in a net electrical charge. An atom that lost an electron is called a cation and is positively charged. An atom that gained an electron is called an anion and is negatively charged.A covalent bond is a chemical bond between two atoms where each atom shares one of its electrons with the other. Nonpolar bonds are covalent bonds between atoms with similar electronegativities, so the electrons are shared equally. Nonpolar molecules are lipid-soluble/lipophilic and are often found in lipid bilayers of cell membranes. A polar bond is a bond between atoms with different electronegativities so the electrons are shared unequally. Polar molecules are water-soluble/hydrophilic so they readily dissolve in blood and interstitial and intracellular fluid. Polarity is very important to know about a molecule because it lets you know how something is going to react with the body (the body is mostly made of water so polarity decides transport capabilities and the ability to get into cells.) Hydrophilic means “water-loving” and is attracted to and easily dissolved in water. Hydrophobic means“water-fearing” and is not attracted to and insoluble in water. Amphipathic means “love both”. These are molecules containing ionized (polar) groups at one end and nonpolar groups at the other. They have some solubility in both lipid and water. Putting an amphipathic molecule in water causes it to configure itself: polar portions associate with water on the outside, nonpolar portions associate on the inside (can form a bilayer). Electronegativity affects bonds. It is the measure of an atom’s