Circulatory System Quiz
50 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What structural component is unique to veins compared to arteries?

  • Smooth muscle
  • Valves (correct)
  • Connective tissue
  • Endothelium

    • Arteries and veins have the same thickness of walls.

    False

    What is the primary reason for the slower blood flow in capillary beds?

    High resistance and large total cross-sectional area

    The _____ are responsible for the exchange of materials between blood and tissues.

    <p>capillaries</p> Signup and view all the answers

    Match the blood vessel type with its primary function:

    <p>Arteries = Transport blood away from the heart Veins = Return blood to the heart Capillaries = Facilitate material exchange Venules = Collect blood from capillaries</p> Signup and view all the answers

    Which of the following walls is the thinnest?

    <p>Capillaries</p> Signup and view all the answers

    Blood flows back to the heart in veins primarily due to pressure from the heart.

    <p>False</p> Signup and view all the answers

    What is the role of smooth muscle in blood vessels?

    <p>Regulate blood vessel diameter and blood pressure</p> Signup and view all the answers

    What is the term for the fluid that bathes organs directly in an open circulatory system?

    <p>Hemolymph</p> Signup and view all the answers

    A closed circulatory system allows blood to flow freely through the body without any distinction from interstitial fluid.

    <p>False</p> Signup and view all the answers

    What are the three basic components of circulatory systems, regardless of whether they are open or closed?

    <p>Circulatory fluid, blood vessels, heart</p> Signup and view all the answers

    Flatworms possess a large surface area to volume ratio and a __________ cavity.

    <p>gastrovascular</p> Signup and view all the answers

    Match the following terms with their correct descriptions:

    <p>Open circulatory system = Blood bathes organs directly Closed circulatory system = Blood is confined to vessels Gastrovascular cavity = A digestive and circulatory organ in simple organisms Hemolymph = Fluid in an open circulatory system</p> Signup and view all the answers

    Which of the following is NOT one of the four properties of water that arise from hydrogen bonding?

    <p>Acidity</p> Signup and view all the answers

    Hydrophilic substances repel water molecules.

    <p>False</p> Signup and view all the answers

    What is the pH scale used for?

    <p>Measuring the acidity or basicity of a solution.</p> Signup and view all the answers

    A solution is made up of a solute and a _____ .

    <p>solvent</p> Signup and view all the answers

    Which term describes substances that do not mix well with water?

    <p>Hydrophobic</p> Signup and view all the answers

    How do buffers function in biological systems?

    <p>Buffers maintain stable pH levels by neutralizing acids and bases.</p> Signup and view all the answers

    Gastrovascular cavities are primarily found in multicellular organisms.

    <p>False</p> Signup and view all the answers

    What hormone stimulates erythrocyte production when oxygen delivery is low?

    <p>Erythropoietin</p> Signup and view all the answers

    A heart attack results from the death of nervous tissue in the brain.

    <p>False</p> Signup and view all the answers

    What type of cardiovascular disease is characterized by plaque buildup in arteries?

    <p>Atherosclerosis</p> Signup and view all the answers

    Platelets and damaged cells release clotting factors from ________, which contribute to the blood clotting process.

    <p>plasma</p> Signup and view all the answers

    Match the following blood cell types with their corresponding origin:

    <p>Erythrocytes = Myeloid stem cells Lymphocytes = Lymphoid stem cells Platelets = Myeloid stem cells Basophils = Myeloid stem cells</p> Signup and view all the answers

    Which of the following is NOT a type of cardiovascular disease?

    <p>Anemia</p> Signup and view all the answers

    Vitamin K is essential for the process of blood clotting.

    <p>True</p> Signup and view all the answers

    What is the primary function of the platelets in blood?

    <p>To aid in blood clotting</p> Signup and view all the answers

    What is the primary role of low-density lipoproteins (LDLs)?

    <p>Promote plaque formation</p> Signup and view all the answers

    High-density lipoproteins (HDLs) are considered 'bad cholesterol.'

    <p>False</p> Signup and view all the answers

    What lifestyle changes can help reduce hypertension?

    <p>Dietary changes, exercise, and/or medication</p> Signup and view all the answers

    The _____ effect describes how increased carbon dioxide levels lower blood pH and reduce hemoglobin's affinity for oxygen.

    <p>Bohr</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>LDLs = Bad cholesterol associated with plaque formation HDLs = Good cholesterol that reduces cholesterol deposition Hypertension = High blood pressure that increases risk of heart disease Hemoglobin = Molecule that carries oxygen in red blood cells</p> Signup and view all the answers

    In which part of the body does oxygen diffuse from the alveoli into the blood?

    <p>Lungs</p> Signup and view all the answers

    Hemoglobin can carry a maximum of three molecules of oxygen.

    <p>False</p> Signup and view all the answers

    What happens to carbon dioxide levels in tissue capillaries?

    <p>CO2 diffuses into the blood</p> Signup and view all the answers

    What property of water is responsible for its ability to moderate temperature?

    <p>High specific heat</p> Signup and view all the answers

    Ice is denser than liquid water.

    <p>False</p> Signup and view all the answers

    What is the term for the heat required to convert 1 g of water from liquid to gas?

    <p>Heat of vaporization</p> Signup and view all the answers

    Water is often referred to as the __________ of life because it can dissolve many substances.

    <p>solvent</p> Signup and view all the answers

    Match each property of water to its corresponding effect on life:

    <p>Cohesive behavior = Transport of water in plants High specific heat = Temperature stability Density of ice = Insulation of bodies of water Solvent properties = Dissolution of nutrients</p> Signup and view all the answers

    Which of the following statements about water's molecular structure is correct?

    <p>Water molecules can form hydrogen bonds.</p> Signup and view all the answers

    Cohesion refers to the attraction between different substances.

    <p>False</p> Signup and view all the answers

    What is the specific heat of water in cal/g/ºC?

    <p>1 cal/g/ºC</p> Signup and view all the answers

    The ________ scale is commonly used to measure temperature.

    <p>Celsius</p> Signup and view all the answers

    What happens to the temperature of water as it absorbs heat?

    <p>It increases slightly.</p> Signup and view all the answers

    Hydrogen bonds break when water vaporizes.

    <p>True</p> Signup and view all the answers

    What role do hydrogen bonds play in water's specific heat?

    <p>Hydrogen bonds absorb heat when they break and release heat when they form.</p> Signup and view all the answers

    Water's polarity means it can form __________ bonds, enabling it to act as a solvent.

    <p>hydrogen</p> Signup and view all the answers

    Match the following effects of water's properties with their relevance to life:

    <p>Cohesion = Water transport in plants Moderation of temperature = Climate regulation Solvent versatility = Nutrient transport Expansion on freezing = Ice stability on water surfaces</p> Signup and view all the answers

    Study Notes

    Fluid Dynamics: Hydrodynamics of Water and Other Fluids, Fluid Dynamics of Blood

    • Fluid dynamics studies the movement of fluids, encompassing the hydrodynamics of water and other substances, including blood.

    Hydrodynamics of Water

    • Water's movement, across scales, from microscopic algae to larger fish, can be modeled as a continuous medium, treating the fluid as a whole.
    • Tracer particles, like fluorescent beads, are used to visualize velocity fields in water.

    • Although composed of molecules, water can be treated as a continuous medium, useful for studying large-scale movements.
    • Algae and fish movement influences the surrounding water, impacting the flow field.

    Overview: The Molecule that Supports All of Life

    • Water is vital for all life on Earth.
    • Most living organisms require more water than any other substance; most cells are composed of 70-95% water.
    • Water helps create a habitable environment on Earth.

    Concept 3.1: The Polarity of Water Molecules Results in Hydrogen Bonding

    • A water molecule is polar; its ends have opposite charges.
    • Polarity allows water molecules to form hydrogen bonds with each other, influencing several key properties.

    Concept 3.2: Four Emergent Properties of Water Contribute to Earth's Fitness for Life

    • Water demonstrates cohesive, and adhesive properties.
    • It moderates temperature variations.
    • It expands upon freezing.
    • It's versatile as a solvent.

    Cohesion

    • Hydrogen bonds hold water molecules together, a property called cohesion.
    • Cohesion helps water transport against gravity in plants.
    • Adhesion is the attraction between different substances, like water and plant cell walls.

    Surface Tension

    • Surface tension is a physical measure of how difficult it is to break the surface of a liquid.
    • Surface tension is related to cohesive properties and helps some insects walk on water.

    Moderation of Temperature

    • Water absorbs and releases heat from warmer and cooler environments
    • Water can absorb vast amounts of heat without a significant change in its own temperature.
    • High specific heat is valuable, stabilizing temperatures in living organisms and bodies of water.

    Heat and Temperature

    • Kinetic energy is the energy of motion.
    • Heat is the total kinetic energy in a substance.
    • Temperature is a measure of the average kinetic energy of molecules in a material.
    • The Celsius scale measures temperature in degrees.
    • The calorie is a unit of heat.
    • The joule is another unit of energy.

    Water's High Specific Heat

    • Specific heat is the amount of heat a substance must absorb or lose to alter its temperature by 1°C.
    • Water has a high specific heat, requiring substantial heat input to change its temperature.
    • This resistance to temperature change has significant implications for living creatures.

    Evaporative Cooling

    • Evaporation is the change of state from liquid to gas.
    • The heat of vaporization is the energy that a liquid must absorb to change phase to gas.
    • Evaporative cooling results from a surface's loss of heat as a liquid turns to gas.
    • This process regulates temperature in organisms and aquatic environments.

    Insulation of Bodies of Water by Floating Ice

    • Ice floats in liquid water due to a unique hydrogen bond structure that makes ice less dense than the liquid form.
    • Water reaches its maximum density at 4°C.
    • Ice's buoyancy helps insulate bodies of water, permitting life in aquatic environments even in cold temperatures.

    The Solvent of Life

    • A solution is a homogeneous mixture of substances.
    • A solvent is the dissolving agent.
    • A solute is the substance dissolved.
    • An aqueous solution is a solution where water is the solvent.
    • Water is a versatile solvent due to its polarity.

    Hydrophilic and Hydrophobic Substances

    • Hydrophilic substances have an affinity for water.
    • Hydrophobic substances do not have an affinity for water.
    • Oil is hydrophobic because its bonds are nonpolar.
    • Colloids are stable suspensions of fine particles in a liquid.
    • Hydrophilic and hydrophobic properties of substances are important for biological processes.

    Solute Concentrations in Aqueous Solutions

    • Biological reactions occur in water.
    • Reaction rates in water depend on solute concentrations.

    Molecular Mass and Molarity

    • Molecular mass is the sum of masses of all atoms in a molecule.
    • A mole of a substance contains 6.02 x 1023 molecules (Avogadro's Number).
    • Molarity is the number of moles of a solute per liter of a solution.

    Concept 3.3: Acidic and Basic Conditions Affect Living Organisms

    • Water molecules can dissociate into hydrogen (H+) and hydroxide (OH-) ions.
    • Hydronium (H3O+) ion is often represented as H+.
    • Hydroxide (OH-) ion.
    • Water's dissociation happens at a constant rate.
    • Changes in H+ and OH- concentrations profoundly influence cell chemistry.

    Effects of Changes in pH

    • In pure water, H+ and OH- concentrations are equal.
    • Acids increase H+ concentration, and bases reduce it.
    • Biologists use the pH scale to represent the acidity of solutions (the opposite of acidity).

    Acids and Bases

    • Acids increase H+ concentration.
    • Bases decrease H+ concentration.

    The pH Scale

    • In any aqueous solution at 25°C, H+ and OH- concentrations are related (product of H+ & OH-= 10-14).
    • pH is the measure of H+ concentration.
    • 7 is neutral.
    • Values below 7 are acidic, and above 7 are basic.
    • Most biological fluids maintain a pH between 6 and 8.

    Buffers

    • Maintaining a stable pH is crucial for living cells.
    • A buffer is a substance that minimizes changes in pH by absorbing or releasing H+.
    • Most buffers consist of an acid-base pair, reversing combined with H+.

    Threats to Water Quality on Earth

    • Acid precipitation is rain, snow, or fog with a pH lower than 5.6.
    • Acid precipitation is primarily caused by the interaction of pollutants and water in the atmosphere.
    • Acid precipitation can damage lakes, streams, and forests.
    • Human activities contribute to acid rain, impacting ecosystems.

    Consequences of Acid Rain

    • Anthropogenic (human-caused) activities release pollutants.
    • Pollutants can fall at locations far from their source.
    • Damage water and soil quality affecting ecosystems.

    Human Activities Threatening Water Quality

    • Fossil fuel combustion releases CO2
    • Greenhouse gases lead to global warming and ocean acidification.
    • Impacts of this pollution include reduced coral reef formation in the ocean.

    Fluid Dynamics of Blood

    • Circulatory systems are specialized systems in multi-celled organisms that link the body's exchange surfaces (like lungs) with cells throughout the body.
    • Exchange efficiency is heightened in organisms with closed circulatory systems where blood is confined to vessels.

    Overview: Trading Places

    • Every organism exchanges materials with its surroundings, with these exchanges occurring at the cellular level.
    • Unicellular organisms directly exchange materials with the environment.
    • The need for efficient transport of materials with the environment escalates as organisms grow larger and more complex.

    Gastrovascular Cavities

    • Simple animals have a gastrovascular cavity (gvc) in their bodies for both digestion and distribution of materials within the body.
    • The gvc allows for diffusion across cell walls with a large surface area-to-volume ratio.
    • Examples include cnidarians (jellies) and flatworms.

    Open and Closed Circulatory Systems

    • Complex animals have circulatory systems consisting of fluid (blood or hemolymph), tubes (blood vessels), and a pump (heart).
    • Open circulatory systems lack distinct separation between blood and interstitial fluid.
    • Open systems (ex: insects, arthropods, mollusks) allow blood to directly bathe organs.
    • Closed circulatory systems (ex: vertebrates) maintain blood in vessels separate from interstitial fluid. This system enables higher and more consistent blood pressures necessary for larger organisms.

    Organization of Vertebrate Closed Circulatory Systems

    • Humans & other vertebrates have a cardiovascular system - a closed circulatory system.
    • Three main types of blood vessels include arteries (carry blood away from the heart), veins (carry blood toward the heart), and capillaries (for the exchange of materials with the tissues) in capillaries.
    • Networks of capillaries called capillary beds facilitate the exchange between blood and interstitial fluid.

    Single Circulation

    • Bony fish and other aquatic species use single circulation.
    • Blood passes through two capillary beds before returning to the heart.

    Double Circulation

    • In double circulation, blood is pumped separately from the right (oxygen-poor) and left (oxygen-rich) sides of the heart.
    • Oxygen-poor blood travels to the lungs (pulmonary circuit) for oxygen uptake.
    • Oxygen-rich blood returns to the heart.
    • Oxygen-rich blood is then distributed throughout the body (systemic circuit).

    Adaptations of Double Circulatory Systems

    • Amphibians have a three-chambered heart (2 atria + 1 ventricle).
    • Amphibian hearts partially separate oxygenated and deoxygenated blood.
    • Reptiles have either three or four chambers.
    • Crocodilians have a four-chambered heart.
    • Mammals and birds have a four-chambered heart, fully separating the two circulation systems.

    Coordinated Cycles of Heart Contraction Drive Double Circulation in Mammals

    • Mammalian hearts contract rhythmically in a cardiac cycle.
    • The pumping phase is systole, and the relaxation phase is diastole.
    • The cardiac cycle includes coordinated activities of both atria and ventricles to move blood through the system.
    • Blood pressure is the force blood exerts against vessel walls.

    Four Valves Prevent Backflow of Blood in the Heart

    • Atrioventricular (AV) valves separate atria from ventricles.
    • Semilunar valves regulate flow to the aorta and pulmonary artery.
    • Heart sounds are caused by the closure of valves.
    • Defective valves can lead to heart murmurs, associated with abnormal sounds and blood flow.

    Maintaining the Heart's Rhythmic Beat

    • Some muscle cells are self-excitable and contract without nervous system input.
    • The sinoatrial (SA) node (pacemaker) sets the pace of the heart beat.
    • The AV node delays impulses and transmits them for coordinated contraction to the ventricles.
    • Purkinje fibers aid ventricular contraction; the heart's rhythm is adjusted by nervous, hormonal, and environmental factors.
    • An ECG (electrocardiogram) measures conduction through the heart.

    Patterns of Blood Pressure and Flow Reflect the Structure and Arrangement of Blood Vessels

    • Water in plumbing demonstrates principles that also operate within animal circulatory systems.
    • Endothelium lines blood vessels.
    • Structural adaptations of vessels influence blood flow.
    • The endothelium lines blood vessels; the structure and properties determine blood flow and pressure.

    Blood Flow Velocity

    • Physical laws concerning fluid motion in pipes can impact blood flow and pressure.
    • Blood flow in capillaries is slower due to the large total cross-sectional area and higher resistance.
    • Slow flow in capillaries is essential for material exchange between blood and tissues.

    Blood Pressure

    • Blood pressure is the hydrostatic pressure blood exerts against blood vessel walls.
    • Pressure maintenance depends on vessel stiffness and other factors.
    • In more flexible systems, pressure is more readily lost than in more rigid systems.

    Changes in Blood Pressure During the Cardiac Cycle

    • Systolic pressure is the peak pressure during contraction, while diastolic pressure is the lower pressure during relaxation.
    • The pulse is the rhythmic fluctuation in artery pressure, signaling heartbeat.
    • These variations reflect how blood flows through the heart and vessels.

    Regulation of Blood Pressure

    • Various factors, including cardiac output and peripheral resistance from the constriction/dilation of arterioles, affect blood pressure.
    • Vasoconstriction (smooth muscle contraction) leads to higher blood pressure.
    • Vasodilation (smooth muscle relaxation) leads to lower blood pressure.

    How do Endothelial Cells Control Vasoconstriction?

    • Endothelial cells release endothelin, a peptide that controls vasoconstriction.

    Measurement of Blood Pressure (Sphygmomanometer)

    • Blood pressure measurements involve monitoring pressure in an artery using a sphygmomanometer.
    • Steps and techniques including cuff inflation, sound detection, and cuff deflation for reading pressures are involved.

    Overview of Circulation: Additional Considerations

    • Fainting can be caused by insufficient blood supply to the brain.
    • Animals with long necks require high blood pressure.
    • Blood is moved in veins by smooth muscle contractions, skeletal muscle contractions, and the expansion/contraction of the vena cava.
    • In veins, one-way valves prevent backflow.
    • Blood loss and injury both affect circulation and require treatment.

    Capillary Function

    • Capillaries, the body's smallest blood vessels, are frequently filled to capacity in crucial organs.
    • Mechanisms like smooth muscle contraction in arterioles and precapillary sphincter control adjust blood flow in capillary beds.

    Blood Flow in Capillary Beds

    • Blood flow is regulated through contraction and relaxation of precapillary sphincters.
    • This mechanism determines the portion of the blood that enters the capillaries.
    • A thoroughfare channel bypasses capillaries when blood flow isn't needed.

    Blood and Interstitial Fluid Exchange (across Capillaries)

    • Substances exchange between blood and interstitial fluid across the thin endothelial walls of capillaries.
    • Differences in blood pressure and osmotic pressure drive fluid movement between the blood and interstitial fluid.
    • Fluid exchange is crucial for delivering substances to cells and removing waste products.

    Fluid Return by the Lymphatic System

    • The lymphatic system returns any fluid lost from the capillary beds back to the circulatory system.
    • Lymph nodes play a key role in the body's defense mechanisms, filtering lymph.
    • If the lymphatic system fails to maintain balance, swelling (edema) occurs.

    Blood Composition and Function

    • Blood comprises cells (red blood cells, white blood cells, and platelets) suspended in plasma, a liquid matrix.
    • Red blood cells carry oxygen.
    • White blood cells fight infection.
    • Platelets assist in clotting.
    • Plasma comprises water, electrolytes, and proteins like albumin and globulins with various functions, including maintaining water balance.

    Erythrocytes - Oxygen Transport

    • Red blood cells, also known as erythrocytes, are the most prevalent blood cells.
    • They carry oxygen throughout the body.
    • Erythrocytes contain hemoglobin.
    • Hemoglobin, an iron-containing protein, facilitates oxygen transport.

    Leukocytes - Defense

    • Leukocytes, which include monocytes, neutrophils, basophils, eosinophils, and lymphocytes, are vital components of the immune system.
    • They phagocytize bacteria and cell debris or produce antibodies.

    Platelets - Blood Clotting

    • Platelets are cell fragments that play a crucial role in blood clotting.
    • When a blood vessel is damaged, the clotting cascade initiates.
    • Fibrinogen transforms into fibrin, forming a clot.
    • A thrombus in a blood vessel impedes blood flow, necessitating swift intervention.

    Stem Cells and the Replacement of Cellular Elements

    • Blood cells wear out and are constantly replaced.
    • Stem cells in bone marrow produce erythrocytes, leukocytes, and platelets.
    • The hormone erythropoietin stimulates erythrocyte production when oxygen levels are inadequate.

    Cardiovascular Disease

    • Atherosclerosis involves plaque buildup in arteries.
    • A heart attack arises from cardiac muscle death due to coronary artery blockage.
    • A stroke is the death of brain tissue from either blockage or rupture of brain’s blood vessels.

    Treatment and Diagnosis of Cardiovascular Disease

    • Cholesterol contributes to atherosclerosis, and LDLs (bad cholesterol) are closely associated with plaque formation.
    • HDLs, high-density lipoproteins ("good cholesterol") help reduce cholesterol deposition.
    • High blood pressure (hypertension) increases the risk of heart attack and stroke, and may be managed by lifestyle adjustments and/or medications.

    Adaptations for Gas Exchange

    • The body's metabolic demands necessitate effective oxygen transport.
    • Oxygen and carbon dioxide circulate in the blood to match their partial pressures.
    • Adaptations include pigments to bind and transport gases efficiently, along with the structure and functioning of the lungs and circulatory system.

    Hemoglobin

    • Hemoglobin, located within red blood cells, carries oxygen throughout the body.
    • The hemoglobin dissociation curve indicates that a rise or fall in oxygen in tissues leads to changes in oxygen delivery to the cells.
    • CO2 production associated with cellular respiration lowers blood pH, decreasing hemoglobin's affinity for oxygen.

    Membrane Structure and Function

    • The plasma membrane forms a boundary between the cell and its surroundings and exhibits selective permeability.

    The Fluidity of Membranes

    • Membrane fluidity affects functioning.
    • Temperature and lipid composition affect membrane fluidity.
    • Cholesterol helps regulate fluidity and stabilizes membranes.

    Membrane Proteins and Their Functions

    • The membrane's structure includes a mosaic of proteins embedded within the lipid bilayer, with different roles.
    • Proteins determine the membrane’s specific functions.
    • Glycoproteins serve important roles in cell recognition and signaling.

    The Role of Membrane Carbohydrates in Cell-Cell Recognition

    • Cells interact through surface molecules: primarily carbohydrates (glycolipids and glycoproteins).
    • Carbohydrate variations between cells help to recognize each other.
    • Differences in cell surface carbohydrates enable the body to distinguish healthy cells from diseased ones.

    Synthesis and Sidedness of Membranes

    • Membrane synthesis involves the endoplasmic reticulum (ER) and Golgi apparatus.
    • The ER and Golgi apparatus determine the structure and composition of the membrane faces.
    • Membrane sidedness means that one side of the membrane has different composition from the other side, with significant biological implications.

    Concept 7.2: Membrane Structure Results in Selective Permeability

    • Cells regulate the exchange of materials with their surroundings.
    • The plasma membrane’s structure dictates its selective permeability.

    The Permeability of the Lipid Bilayer

    • The lipid bilayer selectively allows the passage of some substances more easily than others, based on polarity and size.

    Transport Proteins

    • Transport proteins facilitate the passage of hydrophilic substances across the membrane.
    • Types of proteins including channel and carrier proteins assist in cellular transport across the membrane.
    • Aquaporins accelerate water diffusion.

    Facilitated Diffusion

    • Facilitated diffusion is a passive process where molecules or substances move down their concentration gradient via transport proteins, expending no energy.
    • Channel and carrier proteins in membranes support this movement.
    • Specific transport proteins aid facilitated diffusion, but the molecules or ions still move passively.

    Effects of Osmosis on Water Balance

    • Osmosis is the diffusion of water across a selectively permeable membrane.
    • Tonicity (related to water movement) determines how cells react in different environments.
    • Hypertonic, hypotonic, and isotonic solutions impact cells with or without walls.

    Water Balance of Cells Without Walls

    • Isotonic solutions maintain cell shape and size.
    • Hypertonic solutions cause water loss (and shrinkage).
    • Hypotonic solutions cause water intake (and swelling).
    • Cells without rigid walls face threats in hypertonic or hypotonic environments.

    Osmoregulation

    • Osmoregulation, the control of water balance in cells or organisms, is essential adaptation for survival.
    • Organisms have evolved mechanisms to adjust to changes in osmotic conditions within their surroundings.
    • Examples include contractile vacuoles in protists (single-celled organisms).

    Water Balance of Cells with Walls

    • Plant cells with cell walls counteract osmotic stress.
    • Turgidity (firmness) is a result of a plant cell in a hypotonic environment absorbing fluid.
    • If plant surroundings are isotonic, the cell becomes flaccid.
    • Plasmolysis occurs when cells lose water in a hypertonic environment with the membrane pulling away from the cell wall resulting in a loss of turgor pressure.

    Facilitated Diffusion: Passive Transport Aided by Proteins

    • Transport proteins speed up passive diffusion across membranes, including water channels (aquaporins).
    • Facilitated diffusion uses transport proteins offering specific pathways for movement across membranes.
    • Gated channels, which operate according to cellular conditions, are vital for cellular functions.

    Active Transport

    • Active transport moves solutes against their concentration gradient.
    • Specific proteins, using energy (often ATP), are necessary for this process.
    • The sodium-potassium pump, a notable example of active transport, maintains concentration gradients across a membrane, transporting sodium out and potassium in, thereby regulating essential ion balances.

    The Need for Energy in Active Transport

    • To move substances against a concentration gradient (in a direction opposite from spontaneous flow), the cell requires energy (generally ATP).

    How Ion Pumps Maintain Membrane Potential

    • Membrane potential is the voltage difference across a cell's membrane.
    • Ion pumps generate and maintain voltage differences across membranes regulating movement of ions and enabling cellular signaling.

    Electrochemical Gradient

    • The electrochemical gradient comprises both the chemical force (concentration gradient) and the electric force (effect of membrane potential) influencing ion diffusion across the membrane.

    Cotransport: Coupled Transport by a Membrane Protein

    • Cotransport occurs when active transport indirectly fuels the transport of another solute.
    • An example includes plants using hydrogen ion gradients to drive nutrient uptake.

    Concept 7.5: Bulk Transport Across the Plasma Membrane

    • Exocytosis and endocytosis enable the transport of large molecules across the membrane.
    • Large molecules utilize vesicles for this transportation.

    Exocytosis

    • In exocytosis, cells transport substances outside of the plasma membrane via membrane fusing with vesicles.

    Endocytosis

    • Cells ingest substances via endocytosis (internalization) through vesicle formation.
    • There are different types of endocytosis- Phagocytosis, pinocytosis, and receptor-mediated endocytosis- depending on the type of substances or molecules engulfed.

    Phagocytosis, Pinocytosis, and Receptor-mediated Endocytosis

    • Phagocytosis involves engulfing solid particles.
    • Pinocytosis involves engulfing extracellular fluid.
    • Receptor-mediated endocytosis is highly specific, concentrating particular molecules before ingestion.

    Additional Considerations

    • A variety of cellular processes rely on membrane transport systems.
    • Disruptions to transport systems can lead to diseases or other negative developments.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Module 3 Life in Motion 01_AK PDF

    Description

    Test your knowledge of the circulatory system, including the differences between arteries and veins, as well as the roles of various components like capillaries and smooth muscle. This quiz covers functional aspects and characteristics of blood vessels. Dive in to discover more about how blood flows and the systems that support it!

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser