A&P I Chapter 1-3 Notes PDF

Summary

These notes cover Chapter 1-3 of a human anatomy and physiology course. The document details the basic structures and functions of the human body, from the chemical, cellular, tissue, organ, and organ system levels.

Full Transcript

‭Chapter 1: The Human Body‬ ‭ natomy vs. Physiology‬ A ‭Anatomy‬‭: the various structures of the body, and their‬‭relationship to one another‬ ‭‬ ‭Gross anatomy: structures visible to the naked eye‬ ‭○‬ ‭Regional vs. systemic anatomy‬ ‭‬ ‭Regional anat...

‭Chapter 1: The Human Body‬ ‭ natomy vs. Physiology‬ A ‭Anatomy‬‭: the various structures of the body, and their‬‭relationship to one another‬ ‭‬ ‭Gross anatomy: structures visible to the naked eye‬ ‭○‬ ‭Regional vs. systemic anatomy‬ ‭‬ ‭Regional anatomy: study the body by region‬ ‭‬ ‭Systemic anatomy: study the body by system‬ ‭‬ ‭Microscopic anatomy: structures that are microscopic (basically looking at cells)‬ ‭○‬ ‭Cytology vs. histology‬ ‭‬ ‭Cytology: study of cells‬ ‭‬ ‭Histology: study of tissues‬ ‭Physiology‬‭: how these individual body parts work (or‬‭function) on a normal level‬ ‭‬ ‭How does this body part keep us alive‬ ‭‬ ‭Most often considered at the cellular/molecular level‬ ‭‬ ‭Considered at the cellular level‬ ‭ rinciple of Complementarity of Structure and Function (this is what ties anatomy and‬ P ‭physiology together)‬ ‭‬ ‭What a structure can do is dependent on its form/structure (physiology depends on‬ ‭anatomy)‬ ‭○‬ ‭Stomach that breaks down food has 3 layers to create strong contractions to make‬ ‭digesting the food easier‬ ‭○‬ ‭If you change the structure, you will almost always change the function‬ ‭‬ ‭Most diseases is usually due to some changes in structure‬ ‭‬ ‭How does this principle relate to anatomy and physiology?‬ ‭Structural Organization of the Human Body‬ ‭1.‬ ‭Chemical level‬ ‭‬ ‭Atoms combine to form molecules‬ ‭2.‬ ‭Cellular level‬ ‭‬ ‭The smallest unit of life‬ ‭‬ ‭Cells can grow individually in number or in size‬ ‭‬ ‭Cells can respond to stimuli‬ ‭‬ ‭Cells that have different functions will look different‬ ‭○‬ ‭Ex. a stomach cell will look different than a cell from your nervous system‬ ‭3.‬ ‭Tissue level‬ ‭‬ ‭Aggregations (collection) of living cells that carry out a similar function‬ ‭○‬ ‭Aggregation: collection of cells‬ ‭○‬ ‭Cells in a tissue should all have similar functions‬ ‭ ‬ ‭Four basic types: muscle, epithelial, nervous, and connective‬ ‭‬ ‭What is the difference between a cell and a tissue?‬ ‭4.‬ ‭Organ level‬ ‭‬ ‭In order for something to be considered an organ, it must be composed of 2 or‬ ‭more tissues that operate together to perform a certain function‬ ‭‬ ‭What is the difference between a tissue and an organ?‬ ‭○‬ ‭Organs will be more complex in function and more specific than tissue‬ 5‭.‬ ‭Organ system level‬ ‭‬ ‭Multiple organs work together to accomplish a purpose‬ ‭‬ ‭Chains of organs that work together‬ ‭‬ ‭Each organ system will contribute to a broader physiology function‬ ‭‬ ‭What is the difference between an organ and an organ system?‬ ‭6.‬ ‭Organismal level‬ ‭‬ ‭All organ systems working together to keep the organism alive‬ ‭○‬ ‭Ex. lung brings in oxygen that all other cells need‬ ‭‬ ‭What is the difference between an organ system and an organism?‬ ‭ ecessary Life Function‬ N ‭Everything we will learn will fit into one of the following necessary life functions‬ ‭1.‬ ‭Maintaining boundaries‬ ‭‬ ‭At the cellular level, and at the organismal level‬ ‭○‬ ‭At the cellular level: the plasma membrane‬ ‭‬ ‭Separates intracellular space and the extracellular space‬ ‭○‬ ‭Organismal level: the skin‬ ‭‬ ‭The skin is important in preventing exposure‬ ‭‬ ‭What are examples at these 2 levels?‬ ‭2.‬ ‭Movement‬ ‭‬ ‭Cooperation of skeletal and muscular systems to coordinate actions‬ ‭○‬ ‭Can be conscious movements, or not‬ ‭○‬ ‭What is an example of this life function‬ ‭‬ ‭Voluntary:‬ ‭‬ ‭Skeletal tissue is what we control‬ ‭‬ ‭Involuntary: we do not control when it contracts‬ ‭‬ ‭Smooth muscle tissue: found in the walls of your hollow‬ ‭organs‬ ‭‬ ‭Cardiac muscle tissue: found in the walls of the heart‬ ‭○‬ ‭Lower part of the brain will control this bc you need‬ ‭about 72 beats/ min to stay alive and function and‬ ‭you would have to focus on that the whole time if it‬ ‭was voluntary‬ ‭ ‬ ‭Movement needs to occur for life to occur‬ ‭3.‬ ‭Responsiveness‬ ‭‬ ‭Body’s ability to receive and respond to change‬ ‭‬ ‭Sensing environmental changes and responding to them‬ ‭‬ ‭Nervous system is primarily involved with excitability‬ ‭‬ ‭Two body cells that is excitable‬ ‭○‬ ‭Neurons‬ ‭○‬ ‭Muscle tissue cells‬ ‭‬ ‭Need to respond to‬ ‭‬ ‭Allows us to move fast‬ ‭‬ ‭If you touch a hot stove, you will move your hand away to‬ ‭prevent damage‬ ‭4.‬ ‭Digestion (breaking down food)‬ ‭‬ ‭Food is broken down to simple molecules to be absorbed to blood and delivered‬ ‭to various tissues‬ ‭5.‬ ‭Metabolism (converting food into energy‬ ‭‬ ‭3 general categories‬ ‭○‬ ‭Catabolism: take large molecules and break it down to smaller parts‬ ‭○‬ ‭Anabolism: take smaller molecules and build it into larger molecules‬ ‭‬ ‭Ex. taking AA to build proteins‬ ‭○‬ ‭Cellular respiration: use ATP‬ ‭‬ ‭electron transport chain produces well over half of the ATP needed‬ ‭6.‬ ‭Excretion‬ ‭‬ ‭Removal of waste produced during digestive and metabolic functions‬ ‭○‬ ‭These waste products usually have some toxic effect‬ ‭‬ ‭Ex. CO‬‭2‬ ‭and nitrogenous waste is disposed‬ ‭○‬ ‭Nitrogenous waste is excreted through the urinary system‬ ‭7.‬ ‭Reproduction‬ ‭‬ ‭Cellular levels: cells must divide for organism to survive‬ ‭‬ ‭There are some processes that will kill off some cells and other processes that will‬ ‭build/repair that so the tissue doesn’t fall apart?‬ ‭‬ ‭This is the only one that doesn’t necessarily have to happen bc not everyone needs‬ ‭to reproduce, but at least some in the population needs to reproduce‬ ‭8.‬ ‭Growth‬ ‭‬ ‭Increase in the number of body cells, or increase in size of individual cells‬ ‭themselves‬ ‭‬ ‭Building must occur faster than break down in body in order for growth to occur‬ ‭○‬ ‭Anabolic reactions have to exceed catabolic reaction‬ ‭Survival Needs‬ ‭Survival need vs necessary life function‬ ‭‬ ‭In order to carry out all of the necessary life functions, you have to have these survival‬ ‭needs‬ ‭1.‬ ‭Nutrients‬ ‭‬ ‭Brought into body by ingestion‬ ‭‬ ‭Includes carbohydrates, fats, proteins along with vitamins and minerals‬ ‭○‬ ‭Carbohydrate and protein: macronutrients bc we need a relatively large‬ ‭amount of it‬ ‭○‬ ‭Vitamins and minerals: micronutrients‬ ‭‬ ‭Vitamins are important for‬ ‭‬ ‭Minerals are structurally important bc minerals are used to build‬ ‭things‬ ‭2.‬ ‭Oxygen‬ ‭‬ ‭Oxygen is required for ETC which is required to make most of your body’s ATP‬ ‭‬ ‭Cells can only survive a few minutes without oxygen‬ ‭3.‬ ‭Water‬ ‭‬ ‭Provides environment for chemical reactions and serves as fluid base for secretion‬ ‭and excretion‬ ‭○‬ ‭Excretion: specifically waste disposal (usually referring to urinary system)‬ ‭○‬ ‭Secretion: the process of which the body removes something the body‬ ‭reproduces‬ ‭‬ ‭Secretion is not necessarily getting rid of something‬ ‭‬ ‭Secretion: a process by which substances are produce and released‬ ‭by a cell or gland for a particular function‬ ‭‬ ‭Ex. sweat glands produce and secrete sweat which is‬ ‭released to the body surface‬ ‭‬ ‭Most of the water is found in body cells‬ ‭‬ ‭Water is important bc it is a solvent‬ ‭‬ ‭Chemical reactions occur in water‬ ‭‬ ‭Some of our important life function use water‬ ‭4.‬ ‭Endothermy‬ ‭‬ ‭We generate our own internal body heat and be maintained‬ ‭‬ ‭Body temperature must be maintained for chemical processes to occur‬ ‭5.‬ ‭Atmospheric pressure‬ ‭‬ ‭Breathing and gas exchange occur at an appropriate atmospheric pressure‬ ‭‬ ‭If you increase or decrease atmospheric pressure, or body might not be able to get‬ ‭enough oxygen‬ ‭‬ ‭Sea level is optimal atmospheric pressure‬ ‭‬ ‭Atmospheric sickness: people get this when they go somewhere with atmospheric‬ ‭pressure they are not used to so they don’t get enough oxygen‬ ‭Homeostasis‬ ‭‬ ‭Homeostasis is the maintenance of the internal condition of the body despite a constantly‬ ‭changing external environment‬ ‭○‬ ‭This maintenance is not a static state‬ ‭‬ ‭Homeostasis is not static so it does not just stay in one place, you can‬ ‭hover around the optimal state‬ ‭○‬ ‭Accomplished by the work of virtually all organ systems‬ ‭‬ ‭Control of homeostasis‬ ‭○‬ ‭Mostly regulated by nervous system and endocrine system‬ ‭‬ ‭Nervous system: the brain tells organs to increase/decrease function at‬ ‭certain times‬ ‭‬ ‭Ex. when you eat food, your brain tells your stomach muscles to‬ ‭contract to digest it‬ ‭‬ ‭Endocrine system: produce and release hormones‬ ‭‬ ‭These systems are not all connected, they are spread out‬ ‭throughout the body‬ ‭○‬ ‭Variable: what organ or function is being controlled or regulated‬ ‭‬ ‭3 parts (or mechanisms) involved in variable control/regulation‬ ‭1.‬ ‭Receptor: some cell type that receives information about the‬ ‭variable‬ ‭‬ ‭Ex. thermal regulation and body temperature‬ ‭○‬ ‭Thermal receptors scattered throughout the body‬ ‭and will receive information abt your body temp‬ ‭and will make a message that will send the message‬ ‭to the control center (usually the brain btu‬ ‭sometimes the spinal cord)‬ ‭○‬ ‭Brain receives the messages and will interpret it and‬ ‭figure out what it means (is the body temp too‬ ‭warm/ too cold)‬ ‭○‬ ‭Once it figures out what the message means, the‬ ‭control center sends out a response message which‬ ‭will be received by the effector‬ ‭○‬ ‭The effector is the part of the body that carries out‬ ‭the response‬ ‭‬ ‭Effector in this case is the skeletal muscle‬ ‭tissues and if it is too cold, your skeletal‬ ‭muscle tissue will start to make you shiver‬ ‭2.‬ ‭Control center: usually the brain but sometimes the spinal cord‬ ‭3.‬ ‭Effector: part of the body that carries out the response‬ ‭‬ E‭ ffectors are not always the same bc if you are too warm,‬ ‭the effectors will be your sweat glands and if you are too‬ ‭cold, it will be the skeletal muscle tissues‬ ‭ ‬ ‭Homeostasis is controlled by negative feedback mechanisms or positive feedback‬ ‭mechanisms‬ ‭○‬ ‭Negative feedback mechanism: causes the variable to change in a direction that is‬ ‭opposite of the initial change‬ ‭‬ ‭Ex. thermoregulation, most hormones‬ ‭‬ ‭○‬ I‭ f your body temp drops, it will tell muscle skeletal glands‬ ‭to bring it back up to the normal range (about 98.6 degrees)‬ ‭○‬ ‭If your body temp rises, it will tell sweat glands to bring it‬ ‭back down to the normal range‬ ‭○‬ ‭Positive feedback mechanism: causes the original change of the variable to be‬ ‭enhances (ex. Accelerates the change)‬ ‭‬ ‭Negative feedback: you don’t want a big change‬ ‭‬ ‭Positive feedback: you want a big change‬ ‭‬ ‭Do not control events that require frequent, small adjustment‬ ‭‬ ‭Ex of positive feedback: labor, blood clotting‬ ‭‬ ‭Blood clot: build up of blood really quickly to prevent blood from‬ ‭leaking‬ ‭‬ ‭Positive feedbacks tend not to last long while negative feedback happens‬ ‭constantly‬ ‭‬ ‭Negative feedback mechanism is more common than positive feedback‬ ‭mechanism‬ ‭ ‬ ‭Imbalances in homeostasis‬ ‭○‬ ‭What can create an imbalance in homeostasis?‬ ‭‬ ‭Aging leads to homeostatic imbalance‬ ‭‬ ‭Control systems become less efficient, making us more susceptible‬ ‭to disease‬ ‭‬ ‭Cascade of events caused by positive feedback mechanisms can‬ ‭overpower negative feedback mechanisms‬ ‭‬ ‭Most variables are controlled by negative feedback mechanism‬ ‭‬ I‭ f something goes wrong, that variable gets controlled by a positive‬ ‭feedback mechanism (drastic increase in activity)‬ ‭ ‬ ‭Autoimmune disorders: body cell starts attacking its own body cells‬ ○ ‭○‬ ‭All known diseases/disorders/conditions are due to some imbalance in‬ ‭homeostasis‬ ‭ natomical Terms‬ A ‭Position & Directional Terms‬ ‭‬ ‭Reference point: anatomical position‬ ‭○‬ ‭Right vs left is always viewed in terms of the person being observed, not your‬ ‭own‬ ‭‬ ‭If someone raises their right hand, it is their right hand, even if you view it‬ ‭and it is to your left‬ ‭‬ ‭Directional terms: help us explain one body part in relation to the others‬ ‭○‬ ‭Dorsal (posterior) vs. ventral (anterior)‬ ‭‬ ‭Dorsal: back side‬ ‭‬ ‭Ventral: belly side‬ ‭○‬ ‭Lateral vs medial‬ ‭‬ ‭Medial: closer to the middle‬ ‭‬ ‭Eye is medial to ear‬ ‭‬ ‭Lateral: further apart‬ ‭‬ ‭Ear is lateral to eye‬ ‭○‬ ‭Distal vs proximal‬ ‭‬ ‭Distal: relative to the point of origin‬ ‭‬ ‭Wrist is distal to shoulder‬ ‭‬ ‭In lab, we learned that distal means lower so the toe is distal to the‬ ‭knee‬ ‭‬ ‭Youtube: point of origin refers to the trunk of the body‬ ‭○‬ ‭Distal means further away‬ ‭○‬ ‭Proximal means closer to body‬ ‭○‬ ‭Ex. elbow is distal to the shoulder‬ ‭○‬ ‭Ex. shoulder is proximal to the fingers‬ ‭‬ ‭Proximal: nearby‬ ‭‬ ‭In lab, we learned that distal means lower so the knee is proximal‬ ‭to the toe‬ ‭○‬ ‭Deep vs superficial‬ ‭‬ ‭Deep: further away from surface‬ ‭‬ ‭Superficial: closer to surface‬ ‭○‬ ‭Superior vs inferior: top vs bottom‬ ‭ ‬ ‭Superior: head is superior to neck‬ ‭‬ ‭Inferior: neck is inferior to head‬ ‭ ‬ ‭Body Planes:‬ ‭○‬ ‭Sagittal: divides body into left and right‬ ‭‬ ‭median/midsagittal plane divides the body exactly in half‬ ‭○‬ ‭Frontal: divides body into anterior and posterior‬ ‭○‬ ‭Transverse: divides body in superior and inferior parts‬ ‭‬ ○ ‭ ‬ ‭Body cavities‬ ‭○‬ ‭Most organs are found in one of the body cavities‬ ‭○‬ ‭Dorsal body cavity: protects organs of the central nervous system (CNS)‬ ‭‬ ‭Composed of the cranial cavity and spinal cavity‬ ‭○‬ ‭Ventral body cavity: houses visceral organs‬ ‭‬ ‭Composed of:‬ ‭‬ ‭Thoracic cavity: contains heart and lungs‬ ‭‬ ‭Abdominopelvic cavity: separated from thoracic cavity by‬ ‭diaphram‬ ‭‬ ‭Ventral body cavity is everything elses but the CNS (dorsal body cavity)‬ ‭‬ ‭Membranes of the Ventral Body Cavity‬ ‭○‬ ‭Serous membrane (serosa): double-layered membrane‬ ‭‬ ‭Visceral serosa: innermost layer covering the organ‬ ‭‬ ‭Parietal serosa: outer layer lining the body wall of the cavity‬ ‭‬ ‭These 2 layers sit close to each other but don’t touch each other‬ ‭‬ ‭2 layers are separated by a small amount of serous fluid (has an‬ ‭oily type of texture)‬ ‭○‬ ‭What is the importance of this fluid?‬ ‭‬ ‭You don’t want visceral and parietal serosa rubbing‬ ‭against each other bc it can cause damage‬ ‭‬ ‭Serous membrane protects your organs‬ ‭‬ ‭Ex. when your heart beats, it can rub up against other organs and‬ ‭the serous membrane prevents this‬ ‭‬ ‭‬ V ‭ isceral and Parietal serous membranes protects each side of the‬ ‭lung bc if there is damage in one side of the lung, it will prevent it‬ ‭from spreading to the other side?‬ ‭‬ ‭Visceral clings to the heart and the parietal clings to the body‬ ‭cavity and there is serous fluid between the visceral and parietal‬ ‭serosa to prevent them from rubbing on each other‬ ‭ ‬ ‭Serous membranes are named according to their location‬ ‭1.‬ ‭Pericardium: serous membrane surrounding the heart‬ ‭○‬ ‭There is a visceral pericardium and a parietal serous‬ ‭2.‬ ‭Pleura: serous membranes surrounding the lungs‬ ‭3.‬ ‭Peritoneum: serous membranes surrounding most organs of the‬ ‭abdominopelvic cavity‬ ‭Chapter 2: Chemistry‬ ‭ ixtures‬ M ‭Mixtures‬‭: any substance containing 2 or more components‬‭physically intermixed‬ ‭‬ ‭In anatomy, for the most part, mixtures will be liquid‬ ‭‬ ‭Types of mixtures‬ ‭1.‬ ‭Solutions‬‭: homogenous mixtures that can exist as a‬‭solid, liquid, or gas composed‬ ‭of very small particles that do not settle out‬ ‭‬ ‭Solvent‬‭is the dissolving medium‬ ‭○‬ ‭Water is the body’s primary solvent‬ ‭‬ ‭Solute‬‭is dissolved in solvent and is usually the‬‭bigger amount than the‬ ‭solvent‬ ‭○‬ ‭Ex. saline solutions (water + NaCl)‬ ‭○‬ ‭Remains suspended‬ ‭○‬ ‭Solvent is equally distributed in the solute bc a solution is‬ ‭homogenous‬ ‭‬ ‭Concentration of a solution can be described using:‬ ‭1.‬ ‭Percent solution‬‭: amount of solute dissolved is expressed‬‭as a‬ ‭percentage of the total solution volume‬ ‭2.‬ ‭Molarity‬‭(mol/L): the number of moles of a substance‬‭per liter of‬ ‭solution‬ ‭‬ ‭Reminder: a mole of any element or compound is equal to‬ ‭its molecular weight‬ ‭2.‬ ‭Colloids‬‭: heterogenous mixtures composed of large‬‭solute particles that do not‬ ‭settle out‬ ‭‬ ‭They are homogenous like solutions????‬ ‭○‬ ‭Solvent is suspended‬ ‭○‬ ‭Different from solution: colloids have bigger particles while‬ ‭solutions have smaller particles‬ ‭‬ ‭Can undergo‬‭sol-gel transformation‬‭→ mixture can change‬‭from a fluid‬ ‭state to more solid state (and back again)‬ ‭○‬ ‭Ex. cytosol of cells changes consistency depending on certain cell‬ ‭activities (cellular division, change in space, etc.)‬ ‭○‬ ‭More solid state → not solid solid but it can go from a liquid state‬ ‭to more of a jello state‬ ‭○‬ ‭Fluid can become thicker or thinner depending on what the cell‬ ‭needs‬ ‭‬ ‭Thicker = more compact?‬ ‭.‬ ‭Suspensions‬‭: heterogeneous mixture composed of large‬‭solute particles that do‬ 3 ‭settle out‬ ‭‬ ‭Unlike collaids which have particles that will not settle out of the solution?‬ ‭‬ ‭Ex. blood contains a fluid portion (called plasma) with various cell types‬ ‭(red blood cells, white blood cells, & platelets) suspended in it‬ ‭○‬ ‭Plasma sits on top when it separates out from the blood‬ ‭Chemical Reactions‬ ‭‬ ‭Occurs when chemical bonds are formed, broken, or rearranged‬ ‭○‬ ‭Chemical bonds are stored energy‬ ‭‬ ‭Types of reactions:‬ ‭1.‬ ‭Synthesis reaction‬‭: formation of bonds between atoms‬‭or molecules to form‬ ‭larger, more complex structures‬ ‭‬ ‭Are‬‭endergonic‬‭→ contains more energy after formation‬ ‭○‬ ‭Need energy to form those bonds‬ ‭‬ ‭Ex. anabolic reactions in the body‬ ‭2.‬ ‭Decomposition reaction: bonds are broken to create smaller molecules or‬ ‭individual atoms‬ ‭‬ ‭Are (mostly)‬‭exergonic‬‭→ release energy when bond is broken‬ ‭○‬ ‭Can be endergonic‬ ‭‬ ‭Ex. catabolic reactions in the body‬ ‭Inorganic Compounds & Their Roles in Homeostasis‬ ‭1.‬ ‭Water‬‭: makes up most of the total body mass and most‬‭of the volume of individual cells‬ ‭‬ ‭Importance in homeostasis:‬ ‭○‬ ‭Universal solvent‬ ‭‬ ‭Transport → water carries nutrients, respiratory gases, metabolic‬ ‭waste, etc.‬ ‭‬ ‭Water can surround some charged structures (ex. Large proteins) to‬ ‭prevent interactions with other charged particles‬ ‭‬ ‭You wrap things in water so that that thing doesn’t make‬ ‭contact with anything else on it’s way to its destination and‬ ‭cause a reaction‬ ‭○‬ ‭High heat capacity‬ ‭‬ ‭Heat capacity: the amount of heat that a substance needs to absorb‬ ‭in order to raise its own temp by 1 degree Celsius‬ ‭‬ ‭Can absorb and release large amounts of heat with little change to‬ ‭its own temperature‬ ‭‬ ‭Why is this important for homeostasis?‬ ‭‬ ‭Various metabolic processes releases a very large amount‬ ‭of heat and water’s high heat capacity helps keep our‬ ‭internal temp stable‬ ‭○‬ ‭Protection‬ ‭‬ ‭Protection is more physical than chemical‬ ‭‬ ‭Water-based body fluids provide a “cushion” for internal organs‬ ‭‬ ‭Ex. if you get hit, water will protect your organs from‬ ‭physical trauma‬ ‭‬ ‭Why is this important for homeostasis?‬ ‭○‬ ‭Heat of vaporization is high‬ ‭‬ ‭Large amount of heat must be absorbed to break bonds & cause‬ ‭evaporation‬ ‭‬ ‭Heat of vaporization is specific to sweating → allows sweat to‬ ‭absorb a lot of our heat which means we don’t have to lose too‬ ‭much water to cool down‬ ‭‬ ‭When our internal temp increases, it vaporizes out from the skin‬ ‭(sweat)‬ ‭‬ ‭Why is this important for homeostasis?‬ ‭○‬ ‭Reactive‬ ‭‬ ‭Water is used in several chemical reaction in the body or produce it‬ ‭‬ ‭Hydrolysis reaction vs dehydration synthesis‬ ‭○‬ ‭Hydrolysis reaction: take a large molecule and you‬ ‭add water to break the bond‬ ‭‬ ‭Ex. compound AB + H‬‭2‬‭O → A-H + B-OH‬ ‭○‬ ‭Dehydration synthesis: remove a water molecule‬ ‭‬ ‭Ex. A-H + B-OH → AB + H‬‭2‬‭O‬ ‭‬ ‭Why is this important for homeostasis?‬ ‭‬ ‭Without water, a lot of chemical reactions will stop if it is‬ ‭hydrolysis-based‬ ‭2.‬ ‭Salts: dissociate (breaking down into positive and negatively changed ions) in solution to‬ ‭form electrolytes (electrolytes are water + the positively charged ions)‬ ‭‬ ‭Importance: electrolytes Na‬‭+‬ ‭and K‬‭+‬ ‭allow for muscle‬‭contraction and‬ ‭transmission of nerve impulses, Fe‬‭+‬ ‭used to carry‬‭O‬‭2‬‭, etc.‬ ‭‬ ‭Iron is found in red blood cells and in responsible for binding to oxygen? For the‬ ‭body to use for ATP production‬ ‭‬ ‭Sodium and potassium are required for the production of electrical pulses for‬ ‭nervous cells and muscle cells‬ 3‭.‬ ‭Acids & Bases: also form electrolytes‬ ‭‬ ‭Acids: release H‬‭+‬ ‭ions in solution‬ ‭○‬ ‭Cause pH to drop‬ ‭‬ ‭Bases: release OH‬‭-‬ ‭ions in solution‬ ‭○‬ ‭Causes pH to increase‬ ‭‬ ‭Optimal blood pH is 7.2 - 7.4‬ ‭○‬ ‭Ideal bc all out body’s chemical reaction occur within this range‬ ‭○‬ ‭Why is this important for homeostasis?‬ ‭‬ ‭Potential problem: high/low pH disrupts cellular activity, hydrogen bonds, etc.‬ ‭○‬ ‭Chemical reactions either stop or proceeds at a rate not sustainable for life‬ ‭when blood pH is outside of the optimal range‬ ‭‬ ‭Solution?‬‭Buffers‬ ‭‬ ‭Weak acids release some (but not all) H‬‭+‬ ‭○‬ ‭Strong acids will release all of their hydrogen ions‬ ‭○‬ ‭When would this occur?‬ ‭‬ ‭When blood pH becomes too high (basic)‬ ‭‬ ‭Weak bases tie up excess H‬‭+‬ ‭when pH becomes too acidic‬ ‭○‬ ‭When would this occur?‬ ‭‬ ‭Increase blood pH when it becomes too low‬ ‭(acidic)‬ ‭‬ ‭Result: buffers prevent large changes in pH that could‬ ‭cause excessive damage in the body‬ ‭○‬ I‭ t will change the pH but it will be a small change‬ ‭that your body can handle?‬ ‭Organic Compounds & Homeostasis‬ ‭‬ ‭All organic molecules found in the body contain carbon‬ ‭○‬ ‭Why?‬ ‭1.‬ ‭It is‬‭electroneutral‬‭→ it neither gains nor loses‬‭electrons → it shares it‬ ‭equally‬ ‭2.‬ ‭Can form molecules of various shapes (long chains, rings, etc.) that all‬ ‭have specific functions in the body‬ ‭‬ ‭Long strands can help build fiber (gives it the ability to stretch and‬ ‭return to original shape)‬ ‭‬ ‭DNA are ring-shaped‬ ‭‬ ‭Macromolecules‬‭: polymers that are made up of several‬‭smaller, identical subunits called‬ ‭monomers‬ ‭○‬ ‭Carbohydrates, proteins, and lipids‬ ‭3 Types of Macromolecules: Carbohydrates, Lipids, & Proteins‬ ‭‬ ‭Macromolecules are large in size and are made up of smaller particles (micromolecules?)‬ ‭1.‬ ‭Carbohydrates‬‭: sugars and starches‬ ‭‬ ‭Monomer:‬‭monosaccharides‬ ‭○‬ ‭Monosaccharides: glucose, fructose, galactose‬ ‭‬ ‭Glucose is most important of the 3‬ ‭‬ ‭What the cells use to make ATP‬ ‭‬ ‭The cells can use fructose and galactose to make ATP, but‬ ‭not directly‬ ‭○‬ ‭It has to convert fructose or galactose to glucose‬ ‭○‬ ‭Monosaccharides can form disaccharides, polysaccharides‬ ‭‬ ‭Can disaccharides and polysaccharides be used directly by the‬ ‭body?‬ ‭‬ ‭Yes but not for energy production‬ ‭‬ ‭You have to use glucose for ATP production‬ ‭‬ ‭Major functions:‬ ‭○‬ ‭Fast, easy-to-use energy source‬ ‭○‬ ‭Cell-cell interactions → carbohydrates attached to cell surface, used to‬ ‭communicate‬ ‭‬ ‭Polysaccharides are important for cell-to-cell interactions‬ ‭‬ ‭Your body cell will use those polysaccharides which have‬ ‭stuff pointing ot? (unique to each person) to identify other‬ b‭ ody cells so it knows what belongs in the body and what‬ ‭doesn’t‬ ‭2.‬ ‭Lipids‬ ‭‬ ‭3 types of lipids‬ ‭a.‬ ‭Triglycerides‬ ‭‬ ‭Monomer:‬‭fatty acids and glycerol‬ ‭‬ ‭Varieties of triglycerides:‬ ‭○‬ ‭Saturated‬‭: contains only single covalent bonds, molecules‬ ‭packed closely together‬ ‭‬ ‭Saturated fat tends to be solid at room temp bc the‬ ‭molecules are packed so close to one another‬ ‭‬ ‭Saturated fats can stick to the inside of your‬ ‭blood vessels which wil cause it to be‬ ‭blocked off in time which is why people are‬ ‭told to only eat it in moderate amounts‬ ‭○‬ ‭You don’t want the blood vessels to‬ ‭your heart to be blocked bc this will‬ ‭cause the heart muscles to die off‬ ‭and cause a heart attack‬ ‭‬ ‭Ex. fat found in meat products‬ ‭○‬ ‭Unsaturated‬‭: contains 1 or more double covalent bonds,‬ ‭molecules more spread out which causes it to be more‬ ‭liquid at room temp‬ ‭‬ ‭Not entirely double bonds‬ ‭‬ ‭Considered to be more healthy compared to‬ ‭saturated fats‬ ‭‬ ‭Ex. most plant-based oils‬ ‭○‬ ‭Trans fat‬‭: oil fats that have a H added at sites of‬‭double‬ ‭bonds‬ ‭‬ ‭Tends to be more solids at room temp‬ ‭‬ ‭Tends to be the worst for you and will stick to your‬ ‭blood vessels‬ ‭‬ ‭Ex. doughnuts, cookies‬ ‭○‬ ‭Omega-3 fatty acids‬‭: oil fat found in cold-water fish‬ ‭‬ ‭Ex. krill oil, fish oil capsules, salmon‬ ‭‬ ‭Considered the healthiest of the fat‬ ‭‬ ‭Considered liquid in room temp‬ ‭‬ ‭Major functions: protection, insulation, fast & easily accessible‬ ‭energy storage‬ ‭○‬ ‭Lipids stored in adipose tissue? Fat tissue?‬ ‭b.‬ ‭Phospholipids‬ ‭‬ ‭Modified triglycerides with 2 fatty acid chains and a phosphate‬ ‭group/head‬ ‭○‬ ‭Fatty acid chains are hydrophobic (don’t want to interact‬ ‭with water)‬ ‭○‬ ‭Phosphate “head” is hydrophilic (doesn’t necessarily want‬ ‭to touch it but can touch water with no problem)‬ ‭‬ ‭Major functions: used to build cell membranes (phospholipid‬ ‭bilayer)‬ ‭c.‬ ‭Steroids‬ ‭‬ ‭Most important steroid for life: cholesterol‬ ‭○‬ ‭Cholesterol is used to make all the other steroids so without‬ ‭it, you won’t have any of the other steroids‬ ‭○‬ ‭Ingested in eggs, meat, cheese‬ ‭○‬ ‭Liver produces cholesterol‬ ‭‬ ‭Produces roughly 85% of your daily amount of‬ ‭cholesterol so you only need to provide 15% of‬ ‭cholesterol from your diet‬ ‭‬ ‭1 egg a day is enough for your daily cholesterol,‬ ‭eating more can cause cholesterol to build up in‬ ‭your blood vessels‬ ‭‬ ‭Major functions: structural component of cell membranes, is‬ ‭“base” used by body to form other steroids (steroid hormones -‬ ‭testosterone & estrogens, corticosteroids)‬ ‭○‬ ‭Important structurally in the plasma membranes of your‬ ‭cells‬ ‭○‬ ‭Cholesterols is important for making the cell membrane‬ ‭more stable and more tough‬ ‭‬ ‭It prevents the plasma membrane from‬ ‭breaking/tearing as easily‬ ‭3.‬ ‭Proteins‬ ‭‬ ‭Monomers: amino acids‬ ‭○‬ ‭Specific amino acid sequence leads to large variety of protein functions‬ ‭○‬ ‭Different AA combo lead to different proteins so different functions‬ ‭‬ ‭Structure determines function!‬ ‭a.‬ ‭Fibrous proteins‬‭: proteins form long strands that‬‭can link together to form‬ ‭long, stable structures‬ ‭‬ ‭Function(s): provide mechanical support & tensile strength, some‬ ‭contractile ability‬ ‭‬ T ‭ hey are tough so it will return to its original length even after it is‬ ‭pulled‬ ‭‬ ‭Ex. collagen (skin has to stretch), muscle, joint tissue (gives it‬ ‭flexibility), ligaments (bone-to-bone → when you bend a joint?)‬ ‭b.‬ ‭Globular proteins‬‭: compact, spherical in shape‬ ‭‬ ‭Chemically active (doesn’t mean they are enzymes)‬ ‭‬ ‭Function(s): transport molecules, immune defenses, regulation of‬ ‭growth & development, etc.‬ ‭○‬ ‭If a lipid-based molecule needs to be moved through your‬ ‭bloodstream, you need to bind it to a globular protein‬ c‭.‬ ‭Enzymes‬‭: biological catalysts‬ ‭‬ ‭Function: catalysts lower the activation energy of chemical‬ ‭reactions‬ ‭‬ ‭Varying degrees of‬‭specificity‬ ‭○‬ ‭Some enzymes only catalyze 1 reaction, others can catalyze‬ ‭multiple reactions‬ ‭‬ ‭Importance: without enzymes, most reactions in the body would‬ ‭either not occur or would occur too slowly to‬‭sustain‬‭life‬ ‭(individual will die before the reaction is complete)‬ ‭‬ ‭ATP & Cellular energy‬ ‭○‬ ‭Adenosine triphosphate‬‭(ATP) is *the* energy-transferring/‬ ‭energy-providing molecule of any body cell‬ ‭‬ ‭What is required to produce ATP?‬ ‭‬ ‭oxygen‬ ‭○‬ ‭ATP has a triphosphate tail that has high bond energy (a‬ ‭little unstable so it will transfer a phosphate tail to make it‬ ‭more stable)‬ ‭‬ ‭When a phosphate tail is transferred to another‬ ‭molecule, that molecule temporarily has more‬ ‭energy to do work‬ ‭‬ ‭While doing the work, the molecule loses‬ ‭the phosphate group‬ ‭‬ ‭ATP storage & release is similar to energy needed‬ ‭to drive most chemical reactions‬ ‭‬ ‭What does this mean? Why is it important?‬ ‭‬ ‭There is very little storage of ATP when it comes to‬ ‭body cells‬ ‭‬ ‭A cell only produces as much ATP as it‬ ‭needs at that moment‬ ‭‬ A ‭ TP sitting around that doesn’t do anything‬ ‭is a waste of energy‬ ‭ ‬ ‭Importance: without ATP, chemical reactions stop,‬ ‭cell transport stops, muscle cannot contract‬ ‭‬ ‭All of these lead to body cells dying →‬ ‭death occurs‬ ‭‬ ‭Lack of oxygen is death‬ ‭Chapter 3: Cells: Plasma Membranes‬ ‭The Cells‬ ‭‬ ‭Prefix: “cyto-” (ex. cytoplasm)‬ ‭‬ ‭Suffix: “-cyte” (ex. osteocyte)‬ ‭○‬ ‭-cyte means it is a cell‬ ‭‬ ‭The cell is the smallest living‬ ‭○‬ ‭Different types of cells have different functions in the body‬ ‭‬ ‭What allows cells to have different functions?‬ ‭‬ ‭Microscopic anatomy & the different type of organelles they have‬ ‭○‬ ‭Loss of homeostasis in cells often lead to disease‬ ‭‬ ‭Despite the differences in function, every cell has 3 basic parts‬ ‭1.‬ ‭Plasma membrane: outermost boundary, selectively permeable‬ ‭2.‬ ‭Cytoplasm: intracellular fluid‬ ‭‬ ‭Suspends things in the cells‬ ‭‬ ‭Mostly water, but also contains salts and organic molecules‬ ‭3.‬ ‭Nucleus: controls cellular activities‬ ‭‬ ‭Not all of our body cells have a nucleus‬ ‭○‬ ‭Ex. red blood cells, thrombocytes (help with blood clotting and‬ ‭they don’t need a nucleus bc they don’t live very long)‬ ‭Plasma Membrane‬ ‭‬ ‭Fluid Mosaic Model‬‭describes the general structure‬‭of the plasma membrane‬ ‭○‬ ‭Plasma membrane consistent of a phospholipid bilayer with proteins randomly‬ ‭dispersed in it‬ ‭○‬ ‭Fluid part of the name means the membrane‬ ‭○‬ ‭Mosaic is the proteins that are stuck in the plasma membrane‬ ‭‬ ‭Some of these proteins are mobile‬ ‭‬ ‭Importance: separates the intracellular fluid (ICF) and the extracellular fluid (ECF)‬ ‭‬ ‭Phosphate heads are hydrophilic so they don’t mind water‬ ‭○‬ ‭ICF and ECF are mostly water‬ ‭‬ ‭Fatty acid tails are hydrophobic‬ ‭○‬ I‭ f there is a small tear in the membrane, the fatty acid tails will aggregate so that‬ ‭they prevent water from touching them and it will basically repair the small‬ ‭damage‬ ‭○‬ ‭This is a limited function bc if there is a large tear, the cell won’t survive‬ ‭Chemical Composition of Cell Membranes‬ ‭1.‬ ‭Lipids‬ ‭a.‬ ‭Phospholipids‬‭: forms a basic structure of membrane‬ ‭‬ ‭Polar‬‭Phosphate head: hydrophilic portion contact‬‭ICF or ECF‬ ‭‬ ‭Nonpolar‬‭Fatty acid tails (2): hydrophobic portions‬‭that face the inside of‬ ‭the membrane‬ ‭‬ ‭Aggregation of hydrophobic and hydrophilic regions lead to ability of‬ ‭cells to reseal when damaged/torn‬ ‭b.‬ ‭Cholesterol: provide structural support to “stiffen” the membrane → increases‬ ‭membrane stability‬ ‭2.‬ ‭Proteins‬‭:‬‭constitute most of the cells specialized‬‭membrane functions‬ ‭‬ ‭2 types of membrane proteins by location‬ ‭○‬ ‭Integral proteins‬‭: embedded in the plasma membrane‬ ‭‬ ‭Transmembrane proteins‬‭span the entire width of the‬‭membrane‬ ‭‬ ‭Major functions: transport protein, carriers, enzymes,‬ ‭receptors, cell-cell recognition, etc.‬ ‭○‬ ‭Peripheral proteins‬‭: loosely attached to the integral‬‭potein‬ ‭‬ ‭Are not found *in* the lipid bilayer‬ ‭‬ ‭Major functions: enzymes, motor proteins, cell-cell attachment‬ ‭‬ ‭6 types of proteins by function:‬ ‭1.‬ ‭Transport proteins‬‭: move substances in and/or out‬‭of cells‬ ‭‬ ‭Some proteins (left) form channels through which a particular‬ ‭solute can be selectively moved‬ ‭○‬ ‭What does “selectively” mean?‬ ‭‬ ‭They allow a limited type of substance to pass‬ ‭through‬ ‭‬ ‭Other proteins (right) actively pump substances across the‬ ‭membrane surface by using ATP‬ ‭‬ ‭‬ E ‭ x. Sodium Potassium ATase pump moves sodium and potassium‬ ‭ions in and out of the cell‬ ‭‬ ‭There has to be some conformation change to the transport protein‬ ‭for things to move in and out of the cell‬ ‭2.‬ ‭Receptor proteins‬‭: can relay messages to cell interior‬‭when protein is‬ ‭bound to/exposed to certain chemical messengers‬ ‭‬ ‭When a signal (enzyme?) binds to the receptor, the receptor will‬ ‭change shape which can open up or close up the protein to let‬ ‭things in or out‬ ‭‬ ‭Specificity to chemical messengers can vary bc signals and‬ ‭receptors are specific to each other‬ ‭‬ ‭When bound to chemical messenger → protein changes shape,‬ ‭leading to series of changes inside the cell‬ ‭‬ ‭Ex. receptor protein binds to hormone → cellular activity changes‬ 3‭.‬ ‭Enzymes‬‭: proteins that catalyze chemical reactions‬ ‭‬ ‭Some enzymes act alone, others may act as a “team” to catalyze‬ ‭sequential steps‬ ‭○‬ ‭Each enzyme catalyzes their own part in the reaction‬ ‭‬ ‭4.‬ ‭Cell-cell recognition proteins‬‭: allow body cells to‬‭recognize other body‬ ‭cells‬ ‭‬ ‭What type of cells in the body would need to use this type of‬ ‭protein? Why?‬ ‭○‬ ‭In the immune system, we create our own glycoproteins‬ ‭that are individual to us‬ ‭○‬ ‭Since we are all individualizes, this can help our body tell‬ ‭the difference between our body cells and other cells‬ ‭‬ ‭5.‬ A ‭ ttachment proteins‬‭: helps hold some membrane proteins in place,‬ ‭maintains cell shape‬ ‭‬ ‭Can be located inside of the cell or outside, depending on function‬ ‭‬ ‭6.‬ ‭Intercellular junctions‬‭: some proteins are used to link cells together‬ ‭‬ ‭Length of time to link cells varies (it can be milliseconds to‬ ‭seconds long)‬ ‭‬ ‭Major function: assists with cell migration‬ ‭‬ ‭3.‬ ‭Carbohydrates‬ ‭‬ ‭Extracellular surface is dotted with short-branching carbohydrates‬ ‭○‬ ‭Can be attached to membrane lipids (glycolipids) or proteins‬ ‭(glycoproteins)‬ ‭○‬ ‭Glycolipids and glycoproteins create the‬‭glycocalyx‬‭(sugar coating outside‬ ‭of the cell)‬ ‭‬ ‭Different cell types have different arrangements → allows for‬ ‭identification of cell types by other body cells‬ ‭‬ ‭Can also be used by immune cells to identify “self” cells from‬ ‭“non-self” cells‬ ‭‬ ‭She said think abt each cell having a specific sugar coating‬ ‭and your immune system only recognizes your specific‬ ‭sugar coating and yours‬ ‭‬ ‭Can also contribute to structure/shape of cell membrane‬ ‭Junctions‬ ‭‬ ‭Cell junctions‬‭: a class of proteins that provide contact‬‭or adhesion between two of more‬ ‭cells‬ ‭○‬ ‭Can be permanent or temporary‬ ‭○‬ ‭Types of junctions‬ ‭1.‬ ‭Tight junction‬‭: proteins in cell membranes of neighboring‬‭cells fuse‬ ‭together‬ ‭‬ ‭Tends to be permanent‬ ‭‬ ‭Junction is impermeable‬ ‭‬ ‭Ex. tight junctions between epithelial cells of stomach prevent‬ ‭gastric juice from “leaking out”‬ ‭‬ ‭2.‬ ‭Desmosomes‬‭: anchoring junctions from one cell to another‬‭that prevents‬ ‭separation‬ ‭‬ ‭Ex. skin‬ ‭‬ ‭They are not impermeable like tight junctions‬ ‭‬ ‭Function: bind cells together to form sheets that resist shearing‬ ‭forces when pulled/stretched‬ ‭‬ ‭Components of a desmosome:‬ ‭○‬ ‭Cadherins‬‭: protein filaments extend from cell surface and‬ ‭link to filaments on other cell surface‬ ‭‬ ‭Blue part/ velcro looking thing‬ ‭○‬ ‭Inside the cell, a‬‭plaque‬‭holds the cadherins in place‬ ‭‬ ‭Orange part‬ ‭‬ ‭Keratin filaments‬‭: hold plaque in place to prevent‬ ‭excessive movement/shifting‬ ‭○‬ ‭‬ ‭Cells that usually stretch have desmosomes‬ ‭○‬ ‭Ex. skin cells have desmosomes to allow it to stretch‬ ‭without the cells being torn from one another‬ ‭3.‬ ‭Gap junctions‬‭: also called “comunication” junctions‬ ‭‬ ‭Intercellular channels between 2 cells‬ ‭‬ ‭Hollow cylinders (formed by proteins) connect adjacent cells‬ ‭○‬ ‭Different proteins used to create gap junctions = selective‬ ‭passage of molecules/substances through channels‬ ‭(‬‭semipermeable‬‭)‬ ‭‬ ‭Biggest function is ion exchange‬ ‭‬ ‭Gap junction are selective on what they allow movement of‬ ‭‬ ‭Membrane Transport: Passive‬ ‭‬ ‭Definition: movement of molecules across the membrane down their concentration‬ ‭gradient (diffusion) with no ATP required‬ ‭○‬ ‭Driving force of diffusion: kinetic energy of molecules‬ ‭‬ ‭In areas of high molecule concentration → molecules collide and bounce‬ ‭off one another more frequently‬ ‭‬ ‭How does the rate of collision affect the dispersal (or diffusion) of‬ ‭molecules?‬ ‭○‬ ‭The faster they bounce off one another means they faster‬ ‭they will disperse‬ ‭○‬ ‭The more frequently molecules collide and bounce off each‬ ‭other, the more frequently dispersal will take place‬ ‭○‬ ‭Diffusion speed determined by 3 factors:‬ ‭1.‬ ‭Concentration‬‭: greater concentration difference between‬‭2 areas‬ ‭‬ ‭In areas of high molecule concentration → molecules collide and‬ ‭bounce off one another more frequently‬ ‭○‬ ‭The faster they bounce off one another means they faster‬ ‭they will disperse‬ ‭○‬ T ‭ hey more frequently molecules collide and bounce off‬ ‭each other, the more frequently dispersal will take place‬ ‭2.‬ ‭Molecular size: smaller molecule diffuse faster‬ ‭‬ ‭Larger molecule collides slower than smaller molecules‬ ‭○‬ ‭Diffusion takes place faster for smaller molecules than for‬ ‭larger‬ ‭○‬ ‭ALL MOLECULES HAVE THE SAME KINETIC‬ ‭ENERGY‬ 3‭.‬ ‭Temperature: higher temperatures result in faster diffusion rate‬ ‭‬ ‭Colder temp decreases kinetic energy of the molecules so they‬ ‭collide less frequently‬ ‭‬ ‭Vice versa for hotter temp‬ ‭Types of Diffusion (Passive)‬ ‭1.‬ ‭Simple Diffusion‬‭: diffusion of substance directly through the lipid bilayer‬ ‭‬ ‭Most molecules diffusing are small in size and nonpolar‬ ‭○‬ ‭Fatty acid tails are nonpolar so other nonpolar molecules can diffuse easily‬ ‭○‬ ‭Polar molecules will not be able to diffuse as easily bc fatty acid tails areb‬ ‭hydrophobic and don’t want to touch polar things‬ ‭‬ ‭Ex. most gases, steroid hormones, fatty acids‬ ‭2.‬ ‭Facilitated diffusion‬‭: diffusion of molecules through‬‭the membrane with the used of a‬ ‭protein‬ ‭‬ ‭Types of facilitated diffusion:‬ ‭1.‬ ‭Carrier-mediated‬‭: transmembrane proteins used to carry large molecules‬ ‭through the membrane‬ ‭‬ ‭Protein changes shape while moving substances‬ ‭‬ ‭Limits: the cell can only move substances as fast as proteins‬ ‭become available to move them‬ ‭‬ ‭○‬ O ‭ ne side opens up and then it closes for the other side to‬ ‭open up and allow the substance in‬ ‭○‬ ‭Proteins can only move molecules one at a time?? Connects‬ ‭to limits???‬ ‭2.‬ ‭Channel-mediated‬‭: transmemebrane proteins form‬‭water-filled channels‬ ‭through which molecules can pass‬ ‭‬ ‭Selective → size od channel determines what substance can/cannot‬ ‭pass through‬ ‭‬ ‭Proteins can form leaky or gated channels‬ ‭○‬ ‭Leaky: there is nothing to close the channel so whatever‬ ‭substance the protein is trying to transport can be‬ ‭transported consistently‬ ‭‬ ‭○‬ ‭Gated: means there is a door on one side of the channel so‬ ‭either on the intracellular side or extracellular side‬ ‭3.‬ ‭Osmosis‬‭: diffusion of water through a selectively‬‭permeable membrane‬ ‭‬ ‭Movement of water across a semipermeable membrane from a less concentrated‬ ‭solution into a more concentrated solution unil concentration is equal on both‬ ‭sides of the membrane‬ ‭○‬ ‭Can occur without proteins or with the use of‬‭aquaporin‬‭proteins‬ ‭‬ ‭Water loves to follow solute so water moves from a low solute concentration to a‬ ‭high solute concentration‬ ‭○‬ ‭It will move to one side of the concentration until both sides are balanced‬ ‭○‬ ‭Water can squeeze through the plasma membrane but aquaporin proteins‬ ‭can help move water molecules too‬ ‭‬ ‭Osmolarity‬‭: total concentration of all solute particles in a solution‬ ‭○‬ ‭A solution with a high osmolarity will have a greater number of solute‬ ‭particles than a solution with low osmolarity‬ ‭○‬ ‭One solute particle displaces one water molecule‬ ‭‬ ‭What does this mean?‬ ‭○‬ ‭Water moves by osmosis until‬‭hydrostatic pressure‬‭(the pressure of water‬ ‭pushing on the inner cell wall) is equal to‬‭osmotic‬‭pressure‬‭(tendency of‬ ‭water to move into a cell by osmosis)‬ ‭‬ W ‭ hen two pressures are equal → no‬‭net‬‭movement of water is‬ ‭observed‬ ‭‬ ‭When one water molecule leaves the cell, one water molecule‬ ‭enters the cell‬ ‭○‬ ‭‬ ‭Yellow dash line is a free permeable membrane‬ ‭‬ ‭Free permeable membrane: anything can pass‬ ‭‬ ‭Once equilibrium is reached, the volume/concentration of each‬ ‭side won’t change‬ ‭○‬ ‭‬ H ‭ owever, we have semipermeable membranes so this is what‬ ‭semipermeable looks like‬ ‭‬ ‭Water loves to follow solute so water moves from left to right‬ ‭(from the less concentrated solution to the mre concentrated‬ ‭solution)‬ ‭‬ ‭Water moves to the right bc you need more water to dilute a more‬ ‭concentrated solution‬ ‭ ‬ ‭Imbalances in osmosis cause body cells to swell or shrink (depending on total‬ ‭water volume inside cell)‬ ‭‬ ‭ICF is contained by 300mOsm‬ ‭○‬ ‭If you add water, you decrease the concentration which decreases Osm‬ ‭(osmolarity)‬ ‭○‬ ‭If you remove water, you increase the concentration which increases Osm‬ ‭‬ ‭Tonicity‬‭: ability of a solution to change the shape‬‭of a cell by altering the cells‬ ‭internal water volume‬ ‭○‬ W ‭ ater will follow solutes → a change in solution concentration on either‬ ‭side of a membrane will also cause a change in water concentration‬ ‭○‬ ‭Tonicity always refers to the solution that a cell is submerged, NOT‬ ‭THE CELL‬ ‭○‬ ‭Tonicity is something you can see happen‬ ‭○‬ ‭The effect of solutions of varying tonicities on cell size/shape:‬ ‭1.‬ ‭Isotonic solutions‬‭have the same concentration of‬‭nonpenetrating‬ ‭solutes as those found inside the cells‬ ‭‬ ‭Ex. a cell that’s 300mOsm, the solution will also be‬ ‭300mOsm‬ ‭‬ ‭No net loss or gain of water observed‬ ‭‬ ‭If the concentration is the same on each side, what‬ ‭happened to cell size/shape?‬ ‭○‬ ‭Nothing??‬ ‭‬ ‭Ex. 0.9% NaCl solution extracellular fluid‬ ‭2.‬ ‭Hypertonic solutions‬‭have a higher concentration of‬‭solutes than‬ ‭inside the cell‬ ‭‬ ‭Water moves out of the cell which will cause the cell to‬ ‭shrivel up‬ ‭‬ ‭Cell will “shrivel up” or‬‭crenate‬ ‭‬ ‭Ex. 10% NaCl solution‬ ‭3.‬ ‭Hypotonic solutions‬‭have a lower concentration of‬‭solutes than‬ ‭inside the cell‬ ‭‬ ‭Water follows solute so it moves into the cell which causes‬ ‭the cell‬ ‭‬ ‭Cell will “swell up” until they burst (‬‭lyse‬‭)‬ ‭‬ ‭Ex. distilled water‬ ‭ ecretion: a process by which substances are produce and released by a cell or gland for a‬ S ‭particular function‬ ‭‬ ‭Ex. sweat glands produce and secrete sweat which is released to the body surface‬ ‭ ctive Forms of Membrane Transport‬ A ‭Def: movement of molecules across the plasma membrane that requires energy input (use of‬ ‭ATP)‬ ‭‬ ‭Why use energy? Molecules may be too big, too charged, insoluble in lipid membrane, or‬ ‭moving against their concentration gradient‬ ‭○‬ ‭Against gradient: from low to high concentrations‬ ‭‬ ‭Active transport requires transport proteins‬ ‭‬ ‭Types of active transport:‬ ‭1.‬ ‭Primary active transport‬ ‭2.‬ ‭Vesicular transport‬ ‭Primary Active Transport‬ ‭‬ ‭Def: energy required to do work comes directly from ATP hydrolysis by transport‬ ‭proteins called pumps‬ ‭‬ ‭Hydrolysis of ATP (breakdown of ATP) leads to transfer of phosphate group from ATP to‬ ‭the pump‬ ‭‬ ‭Phosphorylation of pump leads to a change in protein shape → allows protein to move‬ ‭molecule across the membrane‬ ‭‬ ‭Important example: Sodium-potassium (Na‬‭+‬ ‭- K‬‭+‭)‬ pump‬ ‭○‬ ‭Uses enzymes Na‬‭+‬ ‭- K‬‭+‬ ‭ATPase enzyme‬ ‭‬ ‭Sodium is pumped out of the cell to the ECF‬ ‭‬ ‭There are 2 binding sites on the other side of the cell for potassium ions‬ ‭‬ ‭Na‬‭-‬ ‭- K‬‭+‬ ‭ATPase pumps sodium out of the cell and potassium‬‭into the cell‬ ‭‬ ‭Pumps Na‬‭+‬ ‭and K‬‭+‬ ‭against their gradient simultaneously‬‭& in opposite‬ ‭directions across the membrane‬ ‭‬ ‭Importance: ATPase pumps maintain electrochemical gradient necessary‬ ‭for function of muscle and nervous tissue‬ ‭Secondary active transport‬ ‭‬ ‭ATP is not directly used‬ ‭‬ ‭Indirectly uses energy stored in concentration gradient of ions created by primary active‬ ‭transport‬ ‭‬ ‭Ex. moving Na‬‭+‬ ‭out of the cell creates concentration‬‭gradient‬ ‭○‬ ‭Cotransport‬‭protein pumps Na‬‭+‬ ‭back into the cell, and carries glucose in to the cell‬ ‭with it‬ ‭Active Transport Systems: Number of Solutes Moved and Direction of Solute Movement‬ ‭1.‬ ‭Symporter: movement of 2 transported substance in the same direction‬ ‭2.‬ ‭Antiporter: movement of 2 transported substances in the opposite direction‬ ‭‬ ‭Ex. Na‬‭+‬ ‭- K‬‭+‬ ‭ATPase‬ ‭3.‬ ‭Uniporter: movement of one substance‬ ‭Vesicular Transport (a type of active transport)‬ ‭‬ ‭Def: movement of fluids with large particles & macromolecules inside membranous sacs‬ ‭called vesicles‬ ‭‬ ‭Functions:‬ ‭1.‬ ‭Endocytosis: movement of a substance into the cell‬ ‭2.‬ ‭Exocytosis: movement of substance out of the cell‬ ‭3.‬ ‭Transcytosis: movement of substances into, across, then out of a cell‬ ‭‬ S ‭ ubstance is outside the cell, a vesicle moves the substance into the cell,‬ ‭across the cell, then out the cell on the other side so it is movin the‬ ‭substance from one side of the cell to another‬ ‭4.‬ ‭Vesicular trafficking: movement of a substance from one area of the cell to‬ ‭another‬ ‭‬ ‭The substance doesn’t move out of the cell, only from one side of the cell‬ ‭to the other (ex. If you need an organelle in another place)‬ ‭Endocytosis‬ ‭‬ ‭Def: vesicular transport used to bring substance into the cell from the ECF‬ ‭○‬ ‭Begins with formation of infolding membrane‬ ‭‬ ‭Types of endocytosis:‬ ‭1.‬ ‭Phagocytosis: cell engulfs large and/or solid material‬ ‭‬ ‭Forms vesicle called a phagosome‬ ‭○‬ ‭Pseudopod formation involves receptors → formation is specific‬ ‭‬ ‭There are receptors on the outside which is why it is‬ ‭specific‬ ‭‬ ‭Phagosome usually fuses with lysosome, where contents are digested‬ ‭○‬ ‭Lysosome are organelles that break down things‬ ‭‬ ‭○‬ T ‭ he red substance is engulfed by a cell as you can see on the top‬ ‭where the cell membrane of the cell is connecting to release the‬ ‭substance into the cell‬ ‭2.‬ ‭Pinocytosis: cell brings in a small volume of extracellular fluid containing small‬ ‭solute particles (phagocytosis is with big solid particles)‬ ‭‬ ‭No receptor use needed‬‭→ pinocytosis is not a specific process (unlike‬ ‭phagocytosis)‬ ‭‬ ‭They are sampling their environment so they know what’s going on‬ ‭around them‬ ‭‬ ‭By bringing in ECF, they can see if ions outside are balanced‬ ‭‬ ‭It can help produce warnings‬ ‭○‬ N ‭ eighboring cells can produce a chemical warning that cells use‬ ‭pinocytosis to sense to let other cells know so they can protect‬ ‭themselves‬ ‭3.‬ ‭Receptor-mediated endocytosis: allows endocytosis of specific substances to‬ ‭occur‬ ‭‬ ‭Like phagocytosis but with smaller substances but receptor mediated can‬ ‭bring substances in faster bc they are smaller‬ ‭‬ ‭Extracellular substances bind to specific receptors proteins‬ ‭‬ ‭Importance: substances can be specifically concentrated in vesicles &‬ ‭brought into cell‬ ‭‬ ‭Fate of contents:‬ ‭1.‬ ‭Substance can be distributed through the cell‬ ‭2.‬ ‭Vesicle can fuse with lysozyme for digestion of concentrated‬ ‭substance‬ ‭‬ ‭Exocytosis‬ ‭‬ ‭Def: vesicular transport used to remove substances from cell to the ECF‬ ‭○‬ ‭Secretory vesicle created around the substance to be removed‬ ‭‬ ‭What is used to form the secretory vesicle?‬ ‭‬ ‭The plasma membrane‬ ‭○‬ ‭Secretory vesicle travels to plasma membrane, fuses with it, and dumps contents‬ ‭out of the cell‬ ‭○‬ ‭Function: hormone secretion, neurotransmitter release, mucus secretion, waste‬ ‭removal‬ ‭Membrane Potential‬‭(potential is another word for‬‭voltage)‬ ‭‬ ‭Selective permeability of plasma membrane generates a membrane potential (voltage)‬ ‭across the membrane‬ ‭○‬ ‭Voltage → electrical potential energy resulting from separation of oppositely‬ ‭charge particles (ions)‬ ‭‬ ‭All cells have a resting membrane potential → voltage difference across cell membrane‬ ‭when cell is at rest‬ ‭○‬ ‭Average of‬‭-70 mV‬ ‭○‬ ‭This voltage is due to the difference in charge from the inside of the cells‬ ‭(negatively charged) to the outside of the cell (positively charged)‬ ‭○‬ ‭All cells are electrically polarized‬ ‭‬ ‭Negatively charged inside‬ ‭‬ ‭Positively charged outside‬ ‭ ‬ ‭How is the resting membrane potential created?‬ ‭○‬ ‭Creation of membrane potential involves an ion imbalance on either side of the‬ ‭plasma membrane‬ ‭○‬ ‭Ion concentrations of Na+ and K+ are different on either side of the membrane‬ ‭‬ ‭Na+ concentration is higher outside the cell‬ ‭‬ ‭K+ concentration is higher insidie the cell‬ ‭‬ ○ ‭ ‬ ‭Potassium ions (K+) have pivotal role in creating the resting membrane potential‬ ‭○‬ ‭Plasma membranes are more permeable to K+ than to Na+‬ ‭‬ ‭Why?‬ ‭○‬ ‭K+ “leaks” out of cell, proteins remain inside the cell‬ ‭‬ ‭What charge do proteins have?‬ ‭‬ ‭Negative‬ ‭○‬ ‭The more K+ that leaves, the more (-) charged the inside of the cell becomes‬ ‭○‬ ‭Some K+ ions will enter the cell → prevents inside of cell from becoming too‬ ‭negative‬ ‭‬ ‭How is the resting membrane potential maintained?‬ ‭○‬ ‭Active transport maintains electrochemical gradients to keep the cell in a steady‬ ‭state‬ ‭‬ ‭What allows for the active transport?‬ ‭‬ ‭Electro = charged‬ ‭ ‬ ‭Chemical = ion concentration‬ ‭ ‬ ‭What role does Na+ have in creating/maintaining the resting membrane potential?‬ ○ ‭‬ ‭Sodium plays no role in creating/maintaining the resting membrane‬ ‭potential, it only changes it‬ ‭Cells & Interactions with the Environment‬ ‭‬ ‭Cells can respond to both extracellular chemicals (hormones, neurotransmitters) and to‬ ‭other surrounding cells‬ ‭○‬ ‭These interactions are used to maintain homeostatic balance in the body‬ ‭○‬ ‭Plasma membrane receptors are important for allowing a cell to interact with its‬ ‭environment‬ ‭Plasma Membrane Receptors‬ ‭‬ ‭Integral proteins at membrane surface serve as binding sites‬ ‭‬ ‭Main functions:‬ ‭1.‬ ‭Contact signaling: cellular recognition by physical contact between cells‬ ‭‬ ‭Importance: normal cellular development and immunity rely on contact‬ ‭signaling‬ ‭2.‬ ‭Chemical signaling: when a chemical messenger (called ligand) binds to a‬ ‭specific receptor and initiates a response‬ ‭‬ ‭Overall process: ligand binds to receptor → receptor structure changes →‬ ‭cell proteins are altered‬ ‭‬ ‭The specific response is linked to the cell’s internal machinery (its‬ ‭structure & function), not the ligand itself‬ ‭○‬ ‭What does this mean about a ligand and its effect on different types‬ ‭of cells‬ ‭‬ ‭Ex. G protein - coupled receptors‬ ‭○‬

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