Physiology Chapter 6 Communication, Integration, and Homeostasis PDF

PHYSIOLOGY CHAPTER 6 "COMMUNICATION, INTEGRATION, AND HOME OSTASIS" Study online at https://quizlet.com/_ejtnun What 2 signals maintain homeostasis? Electrical and chemical Electrical Signal Changes in the membrane...

PHYSIOLOGY CHAPTER 6 "COMMUNICATION, INTEGRATION, AND HOME OSTASIS" Study online at https://quizlet.com/_ejtnun What 2 signals maintain homeostasis? Electrical and chemical Electrical Signal Changes in the membrane potential of a cell Responsible for most communication within the body. They are Chemical Signal secreted by cells into ECF. Also considered hormones. Ligands Ions or neutral molecules that bond to a central metal atom or ion What type of cell responds to Elec/Chem signals? Target cells Specificity Affinity Protein binding need to follow these 4 rules: Competition Saturation The ability of a protein to bind to a certain ligand or a group of What is specificity related ligands. The degree to which a protein is attracted to a ligand is called the What is affinity protein's affinity for the ligand. What is competition Related ligands compete for the binding site. What is saturation The proteins are fully occupied and reached its maximum value. Local communication 2 types of Cell-to-cell communication Long distance communication 1. Gap junctions Local communication examples 2. Conctact-dependent signals 3. Chemicals diffuse Uses a combination of chem/elec signals carried by nerve cells Long distance communication and chemical signals transported through the circulatory system. Allows cytoplasmic transfer of elec/chem signals between adja- Gap junctions cent cells. Occurs when surface molecules on one cell's membrane bind to Contact-dependent signals a surface molecule on another cell's membrane. Chemicals diffuse Diffuse through ECF to act on nearby cells Autocrine signals (self) Act on the same cell that secreted them Paracine cells Are secreted by one cell and diffuse to adjacent cells. Chemical communication example Hormones (secreted by endocrine cells or neurohormones) Action potentials (can be transmitted directly from one cell to the Electrical communication example next in either direction.) Peptides (short chain of amino acids) synthesized and secreted Cytokines by all nucleated cells in response to stimuli. Can be both Are cytokines local comm or long distance In development and differentiation, cytokines usually function as autocrine or paracrine signals. Also play a role in the immune response (e.g. inflammation) Chemical cell-to-cell communication (local or long distance). A cell Signal pathways responds to a particular chemical signal only if the target has a specific receptor. 1. The chemical signal (first messenger) is a ligand that binds to receptor protein 2. Ligand-receptor binding activates the receptor Signal pathway steps 3. The receptor activates one or more intracellular signal mole- cules 1/3  PHYSIOLOGY CHAPTER 6 "COMMUNICATION, INTEGRATION, AND HOME OSTASIS" Study online at https://quizlet.com/_ejtnun 4. The last signal molecule modifies existing proteins or initiates the synthesis of new proteins Diffuse through cell membranes, usually binds cytosolic receptors Lipophilic signal molecules purpose "SLOW" or nuclear receptors. (e.g. steroid hormones) Lipophobic signal molecules *RAPID* Binds receptors on the cell membrane 1. Chemically gated (ligand-gated) ion channels = receptor chan- nels. 2. G-protein coupled 4 categories of membrane receptors 3. Receptor-enzymes 4. Integrin receptors Receptor channels (membrane receptor) Ligand binding opens or closes the channel Ligand binding to a G protein-coupled receptor opens an ion G-protein coupled receptor (membrane receptor) channel or alters enzyme activity. Ligand binding to a receptor-enzyme activates an intracellular Receptor enzyme (membrane receptor) enzyme) Ligand binding to integrin receptros alters enzymes or the cy- Integrin receptor (membrane receptor) toskeleton The transmission of info from one side of the cell membrane to the Signal transduction other side using membrane proteins. Signal transduction: "Transducer" Converts a signal from one form to another Extracellular signal activates the protein kinases and amplifier Signal transduction: "First messenger" enzymes Intracellular signal alters gating of ion channels, increases intra- Signal transduction: "Second messenger" cellular calcium, changes enzyme activity. cAMP - (activates protein kinases, especially PKA, binds to ion channels) What are 2 second messenger pathways that are nucleotides cGMP - (activates protein kinases, especially PKG, binds to ion channels) What is an ion and a second messenger pathway Ca2+ - (Binds to calmodulin and other proteins) What does ligand binding to a receptor channel protein change Permeability to an ion Rapid flow of in and out of the cell, brings about a rapid response Influx vs. Efflux from the cell. Calcium (intracellular second messenger), enters through gated channels (voltage, ligand, mechanical). Novel Signal Molecules Binds calmodulin or other regulatory proteins. Ephemeral Lasting a short time (e.g. gases, best known is Nitrix oxide) Competing ligand that elicits the SAME response as the primary Agonist ligand. Antagonist Blocks receptor activity Up: Increase number of receptors Up-regulation vs. Down-regulation Down: Decrease number of receptors A leads to vessel constriction (smaller) A receptor vs B receptor (e.g. blood vessels) B leads to vessel dilation (bigger) Input (stimulus/receptor) 3 components to a response loop Integration (integrating center compares with setpoint) Output (target/response) 2/3  PHYSIOLOGY CHAPTER 6 "COMMUNICATION, INTEGRATION, AND HOME OSTASIS" Study online at https://quizlet.com/_ejtnun Afferent: a pathway for the signal sent from receptor TO the control center Afferent vs efferent pathway Efferent: pathway for the command AWAY from the control center to the effector Speed (neural is faster) Nervous Vs. Endocrine (speed, duration of action) Duration of action (neural is shorter than endocrine) Neural increases frequency of action potentials How does the nervous system code their stimulus intensity? (in- crease) Endocrine, stimulus intensity is reflected in the amount of hormone released. Put the following molecules of the phospholipase C system in order as they occur in the signaling pathway: 1. phospholipase C 5, 1, 3, 2, 4 2. protein kinase C 3. diacylglycerol (DAG) 4. phosphorylated protein 5. G protein cAMP is formed by converting ATP to cAMP (activates protein When adenylyl cyclase is activated, __________. kinases, especially PKA, alters channel opening and phosphory- lates proteins. Made up of ATP. cGMP is formed by converting GTP to cGMP (activates pro- When guanylyl cyclase is activated, __________. tein kinases, especially PKG. Phosphorylates proteins and alters channel opening.) Made up of GTP. The term used to describe the minimum stimulus to trigger a Threshold response in a feedback loop is __________. __________ allow(s) the body to predict that a change is about to Feedforward control; response loop occur and start the __________ in anticipation of the change. Second messengers include __________. ions, nucleotides, and lipid-derived molecules 3/3  PHYSIOLOGY CHAPTER 12 "MUSCLES" Study online at https://quizlet.com/_eju59z 3 types of muscle Skeletal, cardiac, smooth Multinucleate (more than one nucleus) Multinucleate vs Uninucleate Uninucleate (single nucleus) Striated muscle attached to bone of the skeleton, controls body Skeletal muscle characteristics movement Cardiac muscle characteristics Found in the heart, moves blood through the circulatory system Primary muscle of the internal organs and tubes, influences the Smooth muscle movement of material into, out of and within the body. Skeletal - voluntary, responds to somatic motor neurons Cardiac - involuntary, reponds to autonomic innervation (controls Which muscles are involuntary/voluntary motor and secretory function) Smooth - involuntary, responds to autonomic innervation (controls motor and secretory function) Which muscles are striated? Skeletal and cardiac What muscle is usually attached to bones by tendons? Skeletal muscle Origin Closest to the trunk or to more stationary bone Insertion More distal or more mobile attachment Flexor Brings bones together, decreases joint angle Extensor Moves bones away, increases joint angle Antagonistic muscle group is Flexor-extensor, moves bones in opposite directions. Part of the skeletal muscle, they're long and cylindrical with several Muscle fiber/muscle cells nuclei Lie outside the muscle fiber membrane, needed for muscle regen- Satellite cells/stem cells eration/repair and can form new muscle fibers. Bundled fibers surrounded by CT sheath (this layers of tissue that Fascicles wrap around muscle fibers) What tissue surrounds the entire muscle as well as individual Connective tissue muscle fibers CT sheath purpose Join together to form the tendon Sarcolemma Cell membrane surrounding a skeletal muscle fiber. Sarcoplasm Cytoplasm of a muscle cell Longitudinal tubes with enlarged ends called terminal cisternae. Concentrates and sequesters (isolate) CA2+. *STORES CALCI- UM*. Sarcoplasmic Reticulum Google: a complex network of specialized smooth endoplasmic reticulum that is important in transmitting the electrical impulse as well as in the storage of calcium ions Myofibrils Bundles of interconnected protein filaments of striated muscles. Allows rapid transmission of action potential (electrical impulses) Transverse Tubules (t-tubules) purpose from the cell surface to the interior of the muscle fiber Transverse Tubules (t-tubules) formation Extensions of the sarcolemma (cell membrane of a muscle fiber) T-tubule + 2 flanking terminal cisternae (longitudinal tubules with Triad enlarged end regions) Mitochondria Convert nutrients into the molecule (ATP), which stores energy. Glycogen Granules (cell inclusions) Compacted storage form of glucose found within the cells. The arrangement of thick and thin filaments in a myofibril creates Sarcomere a repeating pattern of alternating light and dark bands. ONE REPEAT OF THE PATTERN IS THE SARCOMERE. 1/4  PHYSIOLOGY CHAPTER 12 "MUSCLES" Study online at https://quizlet.com/_eju59z Z disks I band Sarcomere elements A band H zone M line One sarcomere has 2 Z discs and has filaments betweem them. Z disks Zigzag protein structures that serve as attachment sites for thin filaments. "ZWISCHEN/BETWEEN" Made of thin filaments only, the lightest colored bands. A Z disc runs through the middle of every I band, so each half of an I band I band belongs to a different sarcomere. "ISOTROPIC/SCATTER LIGHT UNIFORMLY" The darkest of the sarcomere's bands where both thin and thick A band filaments overlap and encompass the entire length of a thick filament. "ANISOTROPIC/SCATTER LIGHT UNEVENLY" A clear band in the middle of the A band, thick filaments only. H zone "HELLES/CLEAR" Represents the proteins to which thick filaments attach, equivalent M line to the Z disk for the think filaments. Each M line divides an A band in half. "MIDDLE" Actin What elements are in a thin filament Tropomyosin/troponin Titin/nebulin What element is in a thick filament Myosin Actin Contractile protein that makes up the thin filament. Tropomyosin and Troponin protein type Both are regulatory proteins. Troponin Troponin controls the positioning of an elongated protein polymer. Titin and Nebulin protein type Both are accessory proteins. Tropomyosin To turn. Nebulin is an (inelastic) giant protein that lies alongside thin fila- Nebulin ments and attaches to the Z disk. Helps align the actin filaments of the sarcomere. Titin is the largest known protein (elastic), it stabilizes the position Titin of contractile proteins and its elasticity returns stretched muscles back to resting length. Span the spaces between filaments. When myosin head contacts Crossbridges G-Actin. 2 states (low-force/relaxed muscles) (high-force/contract- ing muscles) Myosin ATPase hydrolyzes ATP into ADP+P Each myosin head has 2 binding sites, (1) actin binding site (2) How do myosin heads energize ATPase site that binds ATP and hydrolyzes it to ADP + P with a release of energy. Brings action potentials (electrical impulses) into the interior of T-Tubules purpose muscle fiber The sarcomere shortens, actin and myosin do not change lengths What happens when the Sarcomere contracts but instead slide past one another (dap each other up). H zone and I band shorten while A band remains constant. Titin spans the distance from one Z disk to the neighboring M line. (Provides elasticity and stabilizes myosin). Nebulin, lying along the Titin and nebulin purpose in muscle contraction thin filaments, attaches to a Z disk but doesn't extend to the M line. (Helps align actin) Muscle Tension Force created by muscle Load Weight or force opposing contraction 2/4  PHYSIOLOGY CHAPTER 12 "MUSCLES" Study online at https://quizlet.com/_eju59z Contraction creation of tension in muscle Relaxation Release of tension 1. Events at the neuromuscular junction Major steps leading up to skeletal muscle contraction 2. Excitation-contraction (E-C) coupling 3. Contraction-relaxation cycle Converts an ACh signal from a somatic motor neuron into an Events at the neuromuscular junction electrical signal in the muscle fiber. 1. Somatic motor neuron releases ACh at the neuromuscular junction 2. Net entry of sodium through the ACh receptor channel initiates EXCITATION (activation of a nerve) CONTRACTION (shortening a muscle action potential. of the actin/myosin filaments of the sarcomere) COUPLING (leads 3. Action potential in t-tubule alters to muscle action) Muscle action potentials are translated into calcium signals. The calcium signals in turn initiate a contraction-relaxation cycle. Also explained by the sliding filament theory of contraction. Also called the muscle "twitch." Contraction-relaxation cycle In depth: The SR pumps calcium back into its lumen , decrease in free cytosolic calcium causes calcium to unbind from troponin, tropomyosin re-covers binding sit, when myosin heads release, elastic elements pull filaments back to their relaxed position. Overlapping actin and myosin myofibrils, the thin filaments slide Sliding filament theory of contraction past the thick filaments in energy-dependent process, resulting in muscle contraction. Troponin controls position of tropomyosin, binds reversibly to calcium Prevents myosin and actin from interacting by covering the myosin tropomyosin binding site calcium release, binds to troponin, troponin pulls tropomyosin from myosin-binding sites on actin, myosin binds tightly to and moves contraction steps actin, repeats as long as binding sites are uncovered and ATP and calcium are available. rigor state occurs when no atp or adp+p are bound to myosin, very brief rigor mortis muscles freeze if no atp is available to release myosin from G-actin starts at rigor state, atp binds to myosin head and myosin de- tatches from g-actin, atp hydrolysis provides energy for the myosin head to rotate and reattach to actin (myosin atpase breaks down Myosin heads step along actin filaments atp to adp+p which rotates the myosin head, new myosin head binds to new g-actin), the power stroke (begins in response to calcium binding to troponin, release of ADP at the end of power stroke which makes room for additional ATP) Anaerobic glycolysis -> produces lactate and pyruvate, small en- ergy released, no oxygen needed Anaerobic glycolysis vs. aerobic respiration Aerobic respiration -> citric acid cycle/ets, oxygen required and large amounts of energy released Resting muscle stores energy from ATP into phosphocreatine, Phosphocreatine then working muscle uses that stored energy. ST -> relies on oxidative phosphorylation (aerobic) Slow twitch, fast twitch, fast-oxidative-glycolytic fibers FT -> relies on glycolysis (anaerobic) FOGS -> Uses oxidative and glycolytic metabolism muscle changes in length and moves load (concentric = shortens, What is Isotonic contractions eccentric = lengthens) Muscle contracts but there is no movement, muscle stays the Isometric contractions same length 3/4  PHYSIOLOGY CHAPTER 12 "MUSCLES" Study online at https://quizlet.com/_eju59z A rigid bar that is free to move around a fixed point (e.g. basketball player's foot that moves while the other has its pivot foot). Lever Bones form this The fixed point around which a lever pivots (e.g. pivot foot of a basketball player) Fulcrum Flexible joints form this Location of smooth muscle urinary, respiratory, reproductive, gastrointestinal, CV systems Phasic smooth muscle pattern Alternates between contraction and relaxation Continuously contracted and only relax when necessary to allow Tonic smooth muscle pattern entry/exit of substances for the organ. Single-unit SM (produces slow contraction for materials to move), Smooth muscle communication with neighboring cells unitary/visceral SM (forms the walls of hollow organs). Multiunit SM (each SM cell receives an input) - Do not have sarcomeres - Controlled by the Autonomic Nervous System/Endocrine system Characteristics of Smooth Muscles - Lack specialized receptor regions unlike skeletal - Contains Acint, myosin, tropomyosin but NO TROPONIN Increase in cytosolic calcium initiates contraction, calcium binds calmodulin, leads to phosphorylation (attachment of phosphate to Smooth muscle contraction steps an ion) of myosin light chains. Dephosphorylation results in relaxation of smooth muscle. - Has an antagonistic control by both sympathetic/parasympathet- Autonomic neurotransmitters and hormones (for SMOOTH MUS- ic neurons CLES) - Most act through G-protein linked receptors - Alters smooth muscle contraction (histamine -> constricts SM Paracine signals (for SMOOTH MUSCLES) airways) (nitric oxide -> relaxes SM of blood vessels) Actin Thin filaments Myosin thick filament, ability to create movement 4/4  PHYSIOLOGY CHAPTER 19 "THE KIDNEYS" Study online at https://quizlet.com/_ek0ja1 1. Regulation of ECF volume and blood pressure. 2. Regulation of osmolarity. 3. Maintenance of ion balance. Functions of the Kidneys 4. Homeostatic regulation of pH 5. Excretion of wastes 6. Production of hormones Renal physiology Study of the kidneys Urinary system (anatomy) Kidneys and accessory structures Paired kidneys purpose modify filtered plasma into urine Paired ureters purpose pass urine from kidney to urinary bladder Urinary bladder purpose stores urine until micturition (peeing) passes urine from bladder to outside the body (males -> exits Urethra purpose the tip of the penis, females -> exits anterior to the vagina and posterior to the clitoris) Retroperitoneal organs meaning Behind the peritoneal cavity Arteries branch off the abdominal aorta and supplies blood to the Renal arteries vs. renal veins kidneys. Veins carry blood from the kidneys to the inferior vena cava. Microscopic tubules that form organized layers. They filtrate/pro- Nephrons duce urine, found mainly in cortex. (Functional unit of the kidney). Outer cortex (80% of nephrons) Kidneys are arranged into which 2 layers Inner medulla (20%) of nephrons Blood flows from renal arteries into an afferent arteriole, into the glomerulus (capillary bed), blood leaving the glomerulus flows into Blood vessels form a portal system/pathway an efferent arteriole, into the second set of capillaries (peritubular capillaries). This converges to form small veins, sending blood out of the kidney through the renal vein. Dividied into an outer cortex (80% nephrons) and an inner medulla Structure of kidney (20% nephrons) Bowman's capsule Site of plasma filtration with the glomerulus. Bowman's capsule combined with glomerulus is referred to as Renal corpuscle Proximal (closeby) tubule Filtered fluid flows in here Segment that dips toward the medulla and then back up. "U" Loop of henle shaped. Fluid passes through here, which drains into a single larger tube Distal (far away) tubule called the collecting duct. Single larger tube towards the end after the distal tube. It con- Collecting ducts verges and drains into the renal pelvis. The filtered and modified fluid (urine) flows into the ureter on its What happens after the renal pelvis way to excretion. The area where the nephrons twists and folds back on itself, where Juxtaglomerular apparatus the final part of the ascending limb of the loop passes between afferent/efferent arterioles. The cortex contains (upper half) All of bowman's capsule, proximal and distal tubes. The medulla contains (lower half) Loop of henle and collecting ducts. One nephron has ____. two arterioles and two sets of capillaries that form a portal system The inside space of a tubular structure, such as an artery or Lumen intestine 1/3  PHYSIOLOGY CHAPTER 19 "THE KIDNEYS" Study online at https://quizlet.com/_ek0ja1 Movement from blood to lumen. Occurs at renal corpuscle which contains filtration barriers. Filtration occurs in the renal corpuscle: Filtration - glomerular capillary endothelium (permeable capillaries, glyco- calyx/barrier) - basement membrane (thin layer that lines most human tissues) - epithelium of Bowman's capsule (podocytes -> cells that covers the outside of the glomerular capillary) From lumen to blood. Occurs with peritubular capillaries and may be active or passive. Most reabsorption takes place in the proximal tubule, with a small- Reabsorption er amount of reabsorption in the distal segments of the nephrons. Regulated reabsorption in the distal nephron allows kidneys to re- turn ions and water to the plasma selectively (needed to maintain homeostasis). From blood to lumen. Occurs with peritubular capillaries. Important in homeostatic regulation (potassium/hydrogen). Active move- Secretion ment of molecules from ECF into nephron lumen. Secretes drugs, toxins, etc. From lumen to outside the body. Excretion = filtration-reabsorp- Excretion tion+secretion. Tells us what the body is eliminating but can't tell the details of renal function. amount filtered - amount reabsorbed + amount secreted = amount 4 processes of Kidneys (FRSE) of solute excreted. FILTRATION of mostly protein-free plasma from the capillaries into Renal corpuscle function (glomerulus + bowman's capsule) the capsule Isosmotic (same osmotic pressure) REABSORPTION of organic Proximal tube function nutrients, ions, and water. SECRETION of metabolites and mole- cules. REABSROPTION of ions in excess of water to create dilute fluid Loop of Henle function in the lumen. Regulated REABSORPTION of ions/water for salt/water balance Distal nephron (distal tubule + collecting ducts) function and pH homeostasis. 1. Capillary blood pressure (ph, hydrostatic, favors filtration) 2. Capillary osmotic pressure (À,opposes filtration, pulls fluid back 3 pressures that influence GFR to plasma) 3. Capsule fluid pressure (hydrostatic pressure is against a mem- brane, inside BC, opposes filtration). Volume of fluid filtered put unit time, it's relatively constant and is GFR (Glomerular Filtration Rate) purpose controlled primarily by regulating blood flow through renal arteri- oles. Increased resistance in afferent arteriole, decreases GFR Increased resistance in efferent arteriole, increases GFR GFR (increased/decreased resistances in afferent/efferent) Decreased resistance in afferent arteriole, increases GFR Decreased resistance in efferent arteriole, decreases GFR Autoregulation of GFR Maintains constant GFR Myogenic Response Ability of vascular smooth muscle to respond to pressure changes A paracrine signaling mechanism through which changes in fluid Tubuloglomerular feedback flow through the loop of Henle influence GFR The nephron loops back on itself so that the ascending limb of the loop of henle passes between the afferent/efferent arteriole. 2/3 PHYSIOLOGY CHAPTER 19 "THE KIDNEYS" Study online at https://quizlet.com/_ek0ja1 The macula densa cells (detect sodium chloride) sense distal The juxtaglomerular apparatus tubule flow and release paracine signals that affect afferent/effer- ent arteriole diameter. Maximum rate of transport that occurs when all carriers are occu- Saturation of Renal Transport pied by substrate. The plasma concentration at which a substance first appears in Renal Threshold the urine. (e.g. glucose, glucosuria/glycosuria meaning glucose in urine which is a sign of diabetes). The sequence of processes in which the kidney deals with a given Renal handling substance Noninvasive way to measure GFR. How much of a plasma that flowed through the glomerulus per unit of time was CLEARED of that substance. Clearance SIMPLE TERMS: Clearance of a solute is the rate at which that substance disappears from the body by excretion. Used to measure GFR. Inulin: Neither reabsorbed or secreted, ONLY EXCRETED. Filter freely in the nephron, so as the nephron continues to reabsorb until no inulin is present, it's considered cleared from inulin since Inulin and creatinine it only excretes. Creatinine: The small amount secreted is small enough to mea- sure creatinine clearance since it's a breakdown product of phos- phocreatine. Removal of urine from body; voiding of the bladder. 2 sphinc- Micturition (Urine) ters control urine flow from bladder (internal/smooth and exter- nal/skeletal sphincter). 3/3