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BIOL 141 Study Guide 3

by: Camryn McCabe

BIOL 141 Study Guide 3 Biol 141

Marketplace > Science > Biol 141 > BIOL 141 Study Guide 3
Camryn McCabe
Penn State
GPA 3.81

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notes from lectures 9-12
Janelle Malcos
Study Guide
Biology, cardiovascular system, Respiratory system
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This 15 page Study Guide was uploaded by Camryn McCabe on Friday March 18, 2016. The Study Guide belongs to Biol 141 at a university taught by Janelle Malcos in Spring 2016. Since its upload, it has received 88 views.

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Date Created: 03/18/16
Study Guide 3 Volume and pressure • For a fixed volume of fluid, pressure depends on the volume of the space it occupies – Large space = lower pressure – Small space = high pressure Pressure gradient: difference in pressures between 2 regions (P – P1) 2  Fluid flows from high pressure to low pressure o Pressure at first point will decrease; pressure at second point will increase Volume and pressure  Volume of chambers change during a heartbeat  Also pay attention to pressure in vessels  Relaxation  Diastole o Space of chamber increases , volume of fluid remains constant  pressure decreases  Contraction  Systole o Space of chamber decreases, volume of fluid remains constant  pressure increases Cardiac Cycle = complete contraction and relaxation  Phase 1: Quiescent Period (before threshold, no action potential) o Atria and Ventricles are in diastole  Pressure of blood vessels > pressure in heart  No pressure in ventricles, therefore AV valves are open and semilunar valves are closed  Blood fills atria and flows through the AV valves to ventricles o Heart fills with blood from bottom up (through atria to ventricles)  Some blood is leftover from previous contraction  Ventricles contain about 90mL of blood (at this point)  NOT the maximum capacity of ventricle o SA node cells are depolarizing (but not to threshold yet) o Pressure in arteries in veins > pressure in chambers o Chambers are all relaxed, high volume  Phase 2: Atrial Systole o SA node depolarizes to threshold (action potential across atria) o Atria contract (systole)  Pressure in atria > pressure in ventricles o Blood is forced into ventricles Study Guide 3  About 40mL more blood  90mL + 40mL = 130mL total  This is the End Diastolic Volume (ventricles)  Phase 3: Isovolumetric contraction o Atria repolarize and relax (diastole)  Start to refill from veins o Ventricles depolarize and begin to contract (early systole)  Contract from bottom up  Blood forces AV valves closed  This makes first heart sound o Pressure in ventricles increases o Blood does not leave ventricles yet  Pressure in aorta and pulmonary artery > pressure in ventricles  Isovolumetric contraction: no change in volume of blood, but ventricles start to contract  Phase 4: Ventricular Ejection o Ventricles fully contract (full systole) o Pressure in ventricles > pressure in vessels  Forces pulmonary and aortic valves open  Semilunar valves are open; AV valves are shut  Blood leaves ventricles  Only 70mL leaves (stroke volume) o Stroke volume: amount that leaves after one stroke (contraction)  60 mL left behind (End Systolic Volume) o End Systolic volume: volume left when completely contracted o Atria are still in diastole  Continue to fill with blood  Phase 5: Isovolumetric Relaxation o Ventricles repolarize and relax (diastole) o Pressure decreases in ventricle  Pressure in pulmonary artery and aorta > pressure in ventricle  Blood tries to flow back, but valves shut and prevent this  This makes the second heart sound o Both sets of valves are still closed so volume of blood in ventricles doesn’t change  Isovolumetric relaxation o When atria are filled, AV valves are forced open  cycle brings again with quiescent period Study Guide 3 End Diastolic Volume – End Systolic Volume = Stroke Volume About 130 mL - About 60 mL = About 70 mL  Cardiac Output (CO) o CO- the amount of blood pumped by the left ventricle in one minute (measures how efficiently our heart pumps blood) o Heart rate (beats/minute) X stroke volume (mL/beat) – HR X SV = CO o On average, total blood volume is pumped through the heart per minute o This is resting cardiac output  What affects heart rate? o Average heart rate = about 75 beats/minute o Autonomic nervous system modulates SA node activity  Without nervous system control, heart would beat about 100 beats/minute (SA node depolarization rate due to leak channels)  Visceral motor responses are initiated from interneurons in “brain centers” o Center- collection of interneurons that receive sensory input about a specific function and create motor output to alter that function o “Cardiovascular control center” (CVCC):  Cardiac control (heart)  Cardioacceleratory neurons  Cardioinhibitory neurons  Vasomotor control (vessels) o Together they regulate blood pressure and heart function  Why out body needs to alter heart rate? o Energy balance o O d2mand o Waste removal (CO ) 2 o Regulate blood pressure  Organ function  Interneurons of the cardioacceleratory center will lead to an increased heart rate o Efferent neurons excited by this center are visceral motor neurons of the sympathetic system o Postganglionic neuron secretes norephinephrine (NE)  Adrenergic receptors on cells of the SA node bind NE Study Guide 3  Cause an increase rate of action potentials of SA node o Maximum heart rate = 230 beats/minute  Limit of SA node excitation  Interneurons of the cardioinhibitory center will lead to an increased heart rate o Visceral motor neurons of the parasympathetic system o Postganglionic neuron secretes Ach  Cholinergic receptors on cells of the SA node bind Ach  Allow potassium to leave the cell  hyperpolarizing reaction  Rate of action potentials decrease o Normal heart rate = 70 beats/minute  Without nervous control the heart would beat about 100 beats/minutes  Sensory input is integrated to create motor output to SA node o Proprioceptors, baroreceptors, chemoreceptors are all integrated together o Proprioceptors (sensory input from muscles and tendons)  Informs brain on changes in physical activity o Baroreceptors (sensory input from blood vessels)  Informs brain on changes to pressure in vessels o Chemoreceptors (sensory input from blood vessels)  Informs brain on changes in CO or2O le2els in the blood (change in chemicals) Cardiovascular System Blood vessels: network of transport throughout the body  Starting point: the heart o Arteries- take blood AWAY from the heart  Oxygen rich (except pulmonary trunk) o Veins- take blood towards the heart  Oxygen poor (except pulmonary veins)  Capillaries- exchange locations Circulatory Routes  Normal flow of blood: o Heart  artery  arteriole  capillary  Arteriole = small artery  Capillary bed = bunch of capillaries  Where exchange of materials occurs o Capillary  venule  vein  heart Study Guide 3  Venule= small vein  Portal system- exception to normal route o Has 2 capillary beds instead of one = 2 places for exchange of materials  2 main systems o Pulmonary (to lungs) o Systemic (to rest of body) Structure of vessels  Vessels have smooth muscle (involuntary control)  All vessels (except capillaries) have 3 layers of tissue: o Tunica intima- in intimate contact with blood; lines interior portion (the lumen = open space inside of tube) o Tunica media- middle; primarily made up of muscle (and collagen); allows for it to constrict and relax o Tunica externa- helps anchor the vessel to surrounding tissue  Tunica = layer  Variations between arteries and veins o Arteries have more tunica media (more muscle and collagen) because they are under higher pressure o Veins have valves  Capillary beds o Only tunica intima is present  Promotes rapid diffusion of material into tissue or capillary  Very narrow, single file travel  Tunica intima = 1 cell thick o Flow of blood is controlled by sphincter muscle cells  Sphincter- circular muscle; single muscle cell  Respond to chemicals in tissue and chemicals from CNS  Contraction of sphincters determines if capillary beds are open or closed  Only about ¼ of body’s capillaries are “open” at any given time  Muscle cells are relaxed  blood flows into capillaries  Muscle cells are contracted > lacking blood, passes through without any exchange Veins  Carry blood back to heart Study Guide 3 o Usually deoxygenated  Thin walls (less muscle and elastic)  Have valves that prevent backflow o Use skeletal muscle contraction as pump to move blood to heart o When valves are closed, blood is forced back up to heart Blood pressure- the force blood exerts against an arterial wall (usually the brachial artery)  Systolic pressure: pressure during ventricle contraction o 1 number of BP o Peak pressure during contraction  Diastolic pressure: pressure during ventricle contraction o 2 ndnumber of BP o Lowest pressure because ventricles are relaxed and not pushing blood into arteries  Mean arterial pressure: average pressure in vessels o Important when considering blood flow to prevent organ failure  Pulse pressure = systolic – diastolic Main variables of blood pressure (3)  Cardiac output o Amount of blood the heart pumps per minute into arteries  Overall arterial volume is constant, but amount of fkuid in arteries is altered o Higher output  more blood in arteries  higher pressure (Sympathetic response) o Lower output  less blood in arteries  lower pressure (parasympathetic response) o Normal Cardiac output (resting)- majority of blood in veins o High Cardiac output- volume in veins lowers, more in arteries  Higher pressure in arteries  Resistance of blood flow in vessels o Combined effect of blood composition, vessel diameter, and vessel length o Vessel diameter can change  vasomotion  Vasoconstriction  smaller vessels, higher blood pressure  Sympathetic action  Anything that raises pressure = sympathetic Study Guide 3  Vasodilation (relaxation)  larger vessels, lower blood pressure  Parasympathetic action  Response to lack of stimulation to contract  Blood volume- total volume of blood in vessels o Mainly controlled by kidneys and hormones Maintaining blood pressure at rest  When at rest, goal is to maintain pressure using a visceral neural circuit o Things that can alter blood pressure at rest: hydration state, posture, stress, disease  Must gather sensory input o Input from baroreceptors (pressure monitors) about current pressure in major arteries o Proprioceptors (in muscles) also provide input BUT not important during rest  Situation changes during exercise or fight or flight  CNS must integrate sensory input o Occurs at cardiovascular control center (CVCC) in medulla  Motor output negates any changes away from homeostasis o Negative feedback loops Blood pressure neuronal circuit  Starts with sensory input to integrating center  Baroreceptors and chemoreceptors provide sensory input to cardiovascular centers in the hindbrain o Baroreceptors: neurons with mechanical-gated sodium channels in membranes of dendrites o Increase in pressure  artery stretches  channel opens  neurons depolarize o Rate of action potentials = amount of stretch  More stretch  more action potentials o Chemoreceptors: important for monitoring pH that alters respiration  Motor output from integrating center o Cells of parasympathetic release Ach  Ach binds to SA node cells and cause them to depolarize slower o Cells of sympathetic release norepinephrine Study Guide 3  Norepinephrine causes SA node cells to depolarize faster  Visceral motor responses (either sympathetic or parasympathetic depending on sensory input) o Sympathetic response  Occurs when blood pressure is too low (baroreceptors tell brain pressure is too low)  Visceral motor neurons cause…  Increased heart rate o Activation of cardioacceleratory neurons  Vasoconstriction o Constriction of blood vessels regulated by sympathetic release of norepinephrine or epinephrine (from adrenal gland) o Parasympathetic response  Occurs when blood pressure is too high  Visceral motor neurons cause…  Decreased heart rate o Activation of cardioinhibitory neurons  Vasodilation o Dilation of blood vessels due to decrease in norepinephrine (lack of secretion from adrenal gland) Respiratory System Main functions of neuronal circuits involved with the heart  Altering blood pressure o Cardiac output alters the amount of blood in the arterial system o This volume has an effect on the blood pressure  Regulating the pH of the blood o CO 2 dissolved in the blood results in an acidic pH o Altering how fast blood moves to the lungs  alters pH  Ensuring proper filtration of blood at kidneys o Remove wastes, preserve water o Filtration of blood at kidneys depends on blood pressure Respiration can mean…  Exchange of gases between tissues  Transport of gases to tissues  Ventilation of lungs (inhalation) o Pulmonary ventilation- inhalation, exhalation  Use of oxygen for metabolism Study Guide 3 The lungs  Composed of a series of tubes (bronchi) that either transport gas or allow for gas exchange o Air conduction tubes- transport gas o Gas exchange tubes- gas exchange  A bronchus has smooth muscle and a plate of cartilage that helps hold the tube open o Smooth muscle can contract and relax (this alters the diameter of the tube)  At the end of each tube is an alveolus, a balloon-like structure consisting of a single cell layer o Where exchange occurs  Air-conducting vs. gas-exchange structures o Conducting zone: mucosa-lined, allows no gas exchange with blood  Supported by cartilage and smooth muscle o Respiratory zone: (gas exchange) thin walled simple squamous epithelium, allows gas exchange with blood  Smooth muscle only in bronchioles  Single cell later in alveoli  Alveolus- balloon-like structure at the end of bronchi that is one cell layer thick o Contain 3 cell types:  Squamous cells: flat cells that make the pouch  Great alveolar cells: produce surfactant that helps reduce water tension so alveolus doesn’t stick to itself  Dust cells: type of immune cell  Help engulf inhaled debris or pathogens  Mobile, travel around alveoli  Alveolus + Capillary = Respiratory Membrane o Each alveolus is intimately associated with a capillary bed o Respiratory membrane is where the alveolus and capillary interact  Separates the air (in alveoli) and blood (in bloodstream)  Only 2 cells thick (capillary epithelium and alveolus squamous cell)  Creates very thin membrane for rapid gas exchange Study Guide 3  1 cell from alveolus + 1 cell from capillary + basement membrane  Basement membrane- non-cellular “glue” between other 2 layers o In alveolus- hi O ,2low CO 2 o In capillary- lo O 2 high CO 2  Gas transport- Oxygen o O i2 required by cells to synthesize ATP through cellular respiration o Transported directly by red blood cells  Blood = blood cells + plasma (liquid bathing the cells)  O binds to hemoglobin (protein found in red blood 2 cells)  Hemoglobin unloads oxygen down a concentration gradient in tissues where O le2els are lower  Gas transport- Carbon Dioxide o CO i2 a waste product from cellular respiration  It’s dissolved in blood plasma as carbonic acid (unstable) that is converted to bicarbonate and protons (carbonic acid equation) - + CO 2 H O 2 H CO  2CO 3 3 + H o Dissolved CO rel2tes to pH of blood because of protons o High protons  very small pH o Low protons  very large pH  Gas Homeostasis – pH of blood o Carbonic acid equation is reversible o Reactants and products determine the direction of the reaction o Products and reactants want to reach equilibrium o pH of blood is maintained at about 7.4  Measurement is associated with the amount of CO 2 o If CO l2vels rise too high:  Production of protons increases  pH lowers  This is called hypercapnia (too much CO ) 2 Study Guide 3  Which results in acidosis (acidic blood; less than 7.35) o If CO levels drop too low: 2  Decrease in protons  pH raises  This is called hypocapnia (too little CO )2  Which results in alkalosis (basic blood; greater than 7.45) Respiratory Neural Circuits  Lungs require its neural connections to work o Do not have internal “pacemaker cells” like the heart  Nervous system monitors and maintains pH homeostasis o Involves respiratory, cardiovascular, and renal systems  Involves afferent, interneurons, and efferent neurons o Afferent- supply sensory input o Interneurons- integrate sensory input at respiratory centers in brain  Located in pons and medulla  These centers set the pace of respiration (involuntary) o Efferent- cause a response  Target diaphragm and rib cage skeletal muscles  Examples of voluntary muscle that are involuntarily activated by the brain  Lungs do not have muscles  Alter contraction of muscles, altering respiratory rate  Afferent neurons o Afferent input travels on sensory neurons o All afferent input is integrated in CNS control centers to determine a motor response o Higher brain centers (cortex)  Emotions  Conscious control o Stretch receptors in lungs  Prevent over inflation of lungs o Irritant receptors in lungs  Tell brain to increase respiratory rate to get irritants out o Proprioceptors  Tell brain to increase respiratory rate to remove CO 2 during high muscle activity o Chemoreceptors Study Guide 3  Peripheral- detect oxygen of blood  Located in major arteries leaving the heart  They increase action potentials when O lev2ls drop  Central- detect CO o2 blood  Located in medulla  Monitor CO l2vels and pH in cerebral spinal fluid  They increase action potentials when CO 2 levels rise (pH drops)  Alter respiratory rate to maintain oxygen levels and pH  Cause motor neurons to increase respiratory rate  Interneurons o Located in brain centers o Action is altered based on input from sensory neurons o Cause change to 2 sets of efferent neurons  Efferent neurons o Efferent signals travel on motor neurons (parasympathetic or sympathetic) o Target tissue determines if visceral or somatic o Inspiratory neurons  Used in “quiet” or normal breathing AND forced breathing  Cause contraction of diaphragm and rib muscles (inhalation)  Exhalation is passive (relaxation of muscles)  More action potentials per time from interneurons in brain center increases respiratory rate (altered by sensory input) o Expiratory neurons  Used in forced/active breathing  Cause contraction of accessory rib muscles and abs (forcing exhalation)  Different muscles than in inhalation  Rhythm is created between inspiratory and expiratory during forced breathing  Because one is sending action potential, and the other is at rest  Examples o At rest Study Guide 3  Baroreceptors/chemoreceptors are monitoring for homeostasis  Changes in pressure/waste in arteries will be negated by efferent path  Either sympathetic or parasympathetic changes o Action  Proprioceptors play a role  Efferent path stimulates sympathetic changes  Parasympathetic is needed to return to rest Structures of the respiratory system  Upper o Nasal cavity o Pharynx  Splitting point- Larynx  Lower o Trachea o Bronchi  Nose and pharynx o Cleanse, warm, and humidify the air as it enters the body o Walls are lined with mucous-producing cells (goblet cells) o Ciliated cells- help move mucous down toward esophagus  Larynx, trachea, bronchi o Provide passage of air to the lungs o All part of air conducting system  Called anatomical dead space because no gas exchange is going on o Trachea- has cartilage in ring like structures o Bronchi- has cartilage plates  Lung Pleura o Lungs are located in thoracic cavity  Thoracic cavity- space enclosed by ribs and muscular diaphragm o Each lung is associated with 2 continuous membranes (pleura)  Visceral pleura- on surface of the lung  Parietal pleura- on inner surface of rib cage  Actually touches the wall Study Guide 3  Space between contains small amount of fluid (pleural fluid)  Causes tension between membranes so they stick o Lung pleura stick together  Therefore, lung volume changes as volume of thoracic cavity changes  Changes caused by muscle contraction  3 pressures of ventilation o Gases move in our lungs based on relationship of 3 pressures o Intrapleural pressure- pressure between membranes  Constant unless injured  Prevents lungs from collapsing (with help of surfactant)  Also helps lungs change size with changing size of thoracic cavity o Atmospheric pressure- air pressure outside the body o Intrapulmonary pressure- air pressure in lungs  If there is a decrease in lung volume, intrapulmonary pressure increases compared to atmospheric pressure  The reverse is true also  Gradients of pressure cause air movement into or out of our lungs (pulmonary ventilation) o Boyles Law  The pressure of a given quantity of gas is inversely proportional to its volume  Gases move high pressure  low pressure  Inhalation o Diaphragm contracts and lowers o Rib muscles contract and expand the cage  Thoracic volume increases  Poutside Pinside o Air moves high pressure  low pressure  Passive exhalation o Diaphragm relaxes and moves up o Rib muscles relax  Thoracic volume decreases  Pinside Poutside Study Guide 3 o Air moves high pressure  low pressure o During “forced” exhalation, other muscles are involved (like abs)  Respiratory rate (f) = breaths per minute (avg. 15)  Tidal volume (V )t= amount of gas inhaled during one breath (avg. 500 mL)  Respiratory Minute Volume (V ) =evolume inhaled in one minute o V = f x V e t o V =e15/minute x 500 mL = 7500 mL or 7.5 liters/minute  Alveolar Ventilation (V e = air at the alveolar respiratory membrane per minute  Respiration process o Pulmonary ventilation- physical movement of air into lungs o Gas diffusion- across respiratory membrane o Gas transport- to tissues in the body  Diffusion at alveoli in lungs or capillary beds of tissue relies on the partial pressure of gases o Each gas contributes a partial pressure to total pressure o Overall pressure- weight of the air on us o Atmospheric pressure = 760 mmHg  Concentration Gradients of Gases o Differences in partial pressure allow for diffusion  Gases diffuse down pressure gradient


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