Physiology 2130 Module 1 to 3 learning outcomes PDF

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💧Module 1-Done? Last edited time Overview Write description of module here Rev 1 Rev 2 Rev 3 UnitModule 1Define physiology study of function in living organisms explores mechanisms by which organisms control internal environment regardless of external environment explains physical and chemical facto...

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Module 1-3

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Module 1 Define physiology study of function in living organisms explores mechanisms by which organisms control internal environment regardless of external environment explains physical and chemical factors responsible for both normal and disease functions (pathology) Define homeostasis Homeostasis is the maintenance of relatively stable conditions within the internal environment regardless of the external environment happenings What is an internal environment fluid in which cells are bathed consists of interstitial fluid

blood plasma What is an external environment region outside body includes space contents (i.e digestive, respiratory and urogenital tracts) How does the body maintain homeostsis Using negative and positive feedback control mechanisms

Describe negative feedback control systems They all work the same way to maintain homeostasis contain a set point, a control center (aka integrator) an effector, a controlled variable and a sensor (aka receptor)

Describe how negative feedback controls body temperature

Set point for body temperature is 37 degrees Actual body temperature could be different depending on external factors Actual body temperature would be detected by sensors in nervous system Signals a control center in a specific region in brain called hypothalamus Control center would notice difference between desired temp (set point) and actual temp Control center would activate organs and systems (the effector) to generate heat (the controlled variable) through shivering and conversing heat by decreasing blood flow to the skin Control center stops (shivering stops) when temp levels match set point and return blood flow to normal decreased temp- blood vessels constrict increased temp- blood vessels dilate

Describe positive feedback control systems Unlike with negative feedbacks where controlled variable eventually shuts off on its own, positive feedback (feedforward systems) systems stimulates its own production Self amplifying mechanisms that produce a vry rapid chenge in physiological system (i.e generation of action potential in nerve cells and surge of luteinizing hormone that causes ovulation of egg from ovary) Describe the process Controlled variable is detected by sensor Signals control center to activate the effector to produce of the controlled variable (cv this way, large amounts of cv are produced

Describe the control systems the two feedback mechanisms rely on to function properly The nervous system brain, spinal cord and all the nerves adapted for rapid communication through its complex system of neurons and nerves Endocrine system Responds more slowly, communicating by release and distribution of hormones in blood List the levels of organization in the human body Atoms make up molecules Molecules make up macromolecules Macromolecules can form cellular organelles Almost all cells contain nucleus cell membrane proteins Some cells take these structures and turn them into specialized structures Group of cells with same specialization grouped together are called tissues Two or more types of tissues are combined to form a complex, functional unit called organs Several organs that operate for a common function are called organ systems When all of organ systems are grouped together, you have an organism All these systems essentially have one common, general function – TO MAINTAIN HOMEOSTASIS!

Module 2

Make a simple diagram of two cells and a nearby capillary. Label the intracellular fluid compartment, extracellular fluid compartment, interstitial fluid compartment, plasma, and cell membrane. Indicate the relative size of each of the compartments in terms of percent of total body water.

Plasma (Extracellular) 6.6% of Total Body Water Interstitial (Extracellular) - 26.4% of Total Body Water Describe the chemical composition of the intracellular fluid, interstitial fluid, and plasma in terms of sodium, potassium, chloride, and proteins. (You do not need to memorize the exact amount, just their relative levels.) Intracellular fluid inside all the cells Extracellular fluid everything outside the cells makes up internal environment of the body divided into interstitial fluid

fluid directly outside, bathing cells plasma watery portion of blood Ions composition Sodium ions (Na+)

Potassium ions (K+)

Calcium ions (Ca++)

Chloride ions (Cl-)

Proteins ions (Pr)

Relative amount

Explain what accounts for the differences in chemical composition of the intracellular and interstitial fluids and plasma. Fluid (42 L) ICF (28 L) 67% Interstitial compartment (11L) 26.4% Plasma (3L) 6.6% Plasma is a yellow fluid that consists of about 92% water and other substances such as proteins, ions nutrients, gases and waste products

Colloidal solution, which is a liquid containing suspended substances that do not settle out of sol'n most are plasma proteins, which include albumins, globulins, and fibrinogen Plasma volume remains relatively constant. Normally, water intake through the digestive tract closely matches water loss through the kidneys, lungs, digestive tract, and skin. Why is there a difference in the ionic composition between the inside and the outside cell? Caused by plasma membrane which forms a physical barrier between the intracellular fluid and extracellular fluid This membrane is selectively permeable means substances can cross very easily, others cannot cross so easily, others cannot cross so easily and some large macromolecules cannot cross at all membrane can do this because do this because it contains channels, pores and special transport systems that regulate the passage of molecules across the membrane

Module 3 Make a diagram of a cell membrane, showing the two parts of the phospholipid bilayer, the positions of membrane proteins, cholesterol, and carbohydrate moieties. Describe the cell membrane Primary func of plasma membrane is to regulate the passage of substances into and out of cell It separates the intracellular and extracellular environments Selectively permeable Proteins, nucleotides and other large molecules needed for the structure and function of the cell cannot penetrate this membrane

Other molecules and many ions can penetrate this membrane to varying degrees Provides two-way traffic for nutrients and waste needed to sustain metabolism while it prevents passage of other substances between the intracellular and extracellular compartments Most abundant component is phospholipid molecules but made up of proteins that form channels and pores, carbohydrate molecules for cell recognition and cholesterol for stability List and describe part of the membrane composed of a phosphate head and lipid tail primary structure of cell membrane is double layer or phospholipid molecules Phospholipid molecule: hydrophilic head face out into the water base solutions inside and outside the cell Phospholipid molecule: hydrophobic tail oriented away from the aqueous and extra and intracellular solutions into the cell membrane Cholesterol molecule inserted into the non-polar lipid layer of membrane helps make membrane impermeable to some water soluble molecules and also helps to keep membrane flexible over a wider temperature range Associated protein: Structural generally attached to inside surface of cell membrane can support and strengthen membrane while others may anchor some cell organs to the intracellular side of membrane Associated protein: Enzyme Associated proteins can be attached either to the intracellular or extracellular surface of the membrane

enzymes act as catalyst for certain rxns immediately inside/outside membrane Carbohydrate molecule groups of carbohydrate molecules can be found associated with extracellular membrane proteins/lipids form protective layer called glycocalyx which plays key role in immune response of the cell and in recognition of other cells in body

Discuss the permeability of the lipid bilayer. Describe phospholipids phospholipids are molecules made up of phosphate head and fatty acid tails. Fatty acid tails of the molecule are hydrophobic while phosphate heads are hydrophillic

What happens when many phospholipids are thrown into water They will align themselves into a lipid bilayer so that the head groups all face out toward the water and the tails away from the water Since fatty acids are hydrophobic, they are the major barrier to water and water-soluble substances such as ions, glucose, urea, and most of other molecules found in living organisms Fat-soluble substances like O2,CO2 and steroid hormones can penetrate this portion of the membrane with ease since they can dissolve through lipid region of membrane List five functions of the membrane proteins. Receptors for the attachment of chemical hormones and neurotransmitters enzymes that help with chemical rxns or breakdown molecules ion channels or pores that allow water-soluble substances, like ions into the cll membrane-transport carriers that transport molecules across the membrane (may include gated channels)

cell-identity markers, like antigens or glycoproteins Antigens are foreign particles that can stimulate immune system

List five major ways substances cross membranes. Endocytosis/exocytosis (pinocytosis for small molecules) Diffusion through protein channels (in the case of water and water soluble molecules) Diffusion through membrane (in case of lipid soluble molecules) Facilitated diffusion Active transport Describe the mechanism of diffusion. Diffusion is the movement of molecules from an area of high conc to low conc due to the molecules random thermal motion (chemical concentration gradient) Electrically charged molecules like Na+ ions tend to move towards opp charges down their electric gradient charged ions can move down both their concentration and electrical gradient If chemical and electrical gradients are in opp directions, movement of ions will depend on the balance of the two gradients and will stop moving when molecules reach electrochemical equilibrium (when electrical force is equal to and in opp direction to chemical force

Describe permeability of lipid soluble substances include O2, CO2, fatty acids, and some steroid hormones Can diffuse right through membrane's lipid bilayer and are not stopped by hydrophobic fatty acid chains Describe permeability of water soluble substances Cannot directly diffuse through fatty acid region of cell membrane but may still cross cell membrane Some including water and many ions like Na+, K+, appear to cross membranes through special protein channels or pores each pore or channel is specific and will generally allow only one type of ion through exceptions exist though List four factors that affect the rate of movement of substances through protein channels. The size of protein channels, which is appoximately 0.8 nm, will limit the size of the molecule The charge on the molecule will affect the rate of movement through channels because the proteins that make up the channels also have charges on them The greater the electrochemical gradient of a molecule, the greater its rate of movement through the channels The number of channels in the membrane affects the rate Describe facilitated diffusion. How does it differ from simple diffusion? Also does not require energy and is powered by the concentration gradient of the molecule Differs from simple diffusion because the rate of transport is limited by the number of available proteins when all carriers are occupied, system becomes saturated and cannot operate any faster Speed at which carrier can change shape or configuration is also limited

once all carriers are working and occupied, they are said to be saturated Shows chemical specificity (a given carrier protein will interact only with a specifically shaped molecule) and may be competitively inhibited by molecules that are very similar in shape

Describe active transport. How does it differ from facilitated diffusion? Like facilitated transport, it requires protein carriers that span the cell membrane Transport mechanism, like facilitated diffusion, can be saturated, shows chemical specificity and shows competitive inhibition Differs from facilitated diffusion in that it requires energy because active transport moves molecules up their concentration gradients from low to high Energy comes from splitting ATP to ADP + P consequent release of energy powers carrier movement

Define osmosis and describe the factors that affect the movement of water across membranes. Define osmotic pressure. Diffusion of the most abundant substance (water) to diffuse requires special pores since it cannot diffuse through hydrophobic portion normally amount that diffuses into cells is equal to amount that diffuses out hence volume remains constant under certain conditions, possible for concentration difference for water to develop across a membrane there is a net movement of water down its concentration gradient when this happens called osmosis

Define solute, solvent and solution Solute substance that is being dissolved in liquid Solvent liquid doing the dissolving Solution what you get when you dissolce a solute in a solvent

Osmosis is the movement of water down its concentration gradient A sol'n that has high conc of solute will consequently have low water conc Pure water will have high water concentration Osmosis across the cell membrane is affected by The permeability of membrane to the solutes in the intracellular and interstitial fluids Concentration gradients of the solutes in the intracellular and interstitial fluids The pressure gradient across the cell membrane What are the units of osmosis A particle that causes osmosis is called an osmatically active particle i.e Na+, Cl-, K+ and glucose Unit used to describe number of osmotically active particles in a sol'n is called an osmole Osmolality = number of osmoles per kg of water Osmolarity = number of osmoles per liter of water Define isotonic, hypotonic, and hypertonic. Describe the effect of such solutions on biological cells.

Tonicity ability of a solution to cause osmosis across a biological cell membrane fluid inside a human cell has a concentration of roughly 300 mOsm/kg water Isotonic solution with the same concentration as the cell = no osmosis will occur Hypotonic solution with a lower conc. = osmosis will occur into the cell cell will swell Hypertonic higher concentration = osmosis will occur out of the cell cell will shrink Describe how chemical and electrical gradients affect the movement of molecules across membranes. The membrane is permeable to a particular ion and that permeability will vary depending on the ion and the particular type of cell In general, most cells are not very permeable to Na+ Cl- and Ca++ Even with large conc gradient for Na+, these ions cannot move K+ is somewhat different the membrane is more permeable to K+ so some will leak out down its concentration gradient Why are there exceptions to the relative ion conc and permeability to each ion Permeability of the cell can (and does) change in certain circumstances Define a resting membrane potential and state its normal polarity and strength (voltage). What is an electrical potential a charge difference between two point What is an membrane potential

difference between inside the cell (-) and outside (+) which is seperated by the membrane What is a resting membrane potential Fluids inside and outside cells are electrolytic (sol'ns that contain ions) Generally a minute excess of negative ions (anions) accumulates immediately inside cell membrane along its inner surface and an equal number of cations accumulates immediately outside Effect of this is the establishment of an electrical potential difference across membrane with inside negative with respect to the outside Since potential difference is present even in resting cells, it is called resting membrane potential. All cells have this What is the strength (voltage) of the resting membrane potential -70 millivolts (mV) in most cases (can vary depending on the cell) Negative number because the negative inside is compared to positive outside Each diffusible ion will have an influence on the resting membrane potential depending on its degree of permeability and its conc gradient. Describe the forces acting on ions and define equilibrium potential. What are the two forces acting on an ion the chemical gradient drives the ion from high to low area of conc electrical gradient drives ion towards area with opp charge When both are equal in magnitude but opp directions, there is no net movement an the ion is said to be in an electrochemical equilibrium The equilibrium potential for a particular ion is the electrical potential that must be applied to the inside of the cell in order to stop mov of that ion down its conc gradient

The larger the conc gradient, the larger the equilibrium potential needed to stop movement of ion Equilibrium potential are the voltages that would have to be applied to inside the cell in order to keep each ion from moving down its conc gradient State the equilibrium potentials for K+, Na+, and Cl– in a nerve membrane. Na+ 60 mV Na+ has a strong conc gradient pushing it into the cell. To keep it out of cell, must apply positive charge inside the cell (+60mV). Same with K+ and Cl- but depends on where they want to go and charge may vary K+ -90 mV Since resting membrane potential is -70mV, some K+ will try to leave and some Na+ will try to enter cell. he Na+/K+ pump balances the leakage of these ions Cl-70 mV Describe the Sodium/Potassium Pump. Na+/K+ is an integral membrane protein Pumps 3 Na+ ions out and 2 K+ ions in Why is it called an electrogenic pump because it contributes to the resting membrane potential by making the inside of the cell more negative pumps both Na+ and K+ against their conc gradient so it requires ATP What form of transport is Na+/K+ pump Active transport since it requires ATP Describe two functions of the Sodium/Potassium Pump Acts to maintain conc gradient of K+ and Na+

Also causes cell to become electronegative on the inside which contributes a small amount to the resting membrane potential Describe additional funcs W/o Na+/K+ pump, most cells would swell until they burst Cells contain large numbers of proteins and other organic compounds to which the cell membrane is impermeable. Many carry - charges and hence attract large positive ions around them. This increases number of particles inside the cell which would cause substantial osmosis of water into the cell Since it pumps 2 potassiums in for every 3 sodiums out, it causes a reduction in particles inside the cell. Causes osmosis of water out of cell and offsets osmosis in the cell, and cell volume is kept constant What is the significance of resting membrane potential Excitable cells can use membrane potential to do work and then spontaneously regenerate electrical potentials at their membranes Two types nerves and muscles...