Introduction to Physiology
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Questions and Answers

Which component is NOT primarily found in the plasma membrane?

  • Glycolipids
  • Phospholipids
  • DNA (correct)
  • Cholesterol

    • What is the main function of the glycocalyx?

  • To enable cell recognition and adhesion (correct)
  • To provide energy for the cell
  • To facilitate cellular respiration
  • To synthesize proteins

    • Which statement about transmembrane proteins is true?

  • They are always composed of carbohydrates.
  • They span the lipid bilayer and interact with both extracellular and intracellular environments. (correct)
  • They only exist on the outer layer of the membrane.
  • They are solely responsible for energy production.

    • Which of the following comprises the basic framework of the plasma membrane?

    <p>Phospholipid bilayer</p> Signup and view all the answers

    What percentage of the plasma membrane is composed of phospholipids?

    <p>75%</p> Signup and view all the answers

    What is the main role of membrane proteins in cells?

    <p>To facilitate the passage of substances and cellular communication</p> Signup and view all the answers

    Which of the following statements accurately describes the fluid mosaic model?

    <p>Proteins float in a fluid lipid bilayer allowing for movement and flexibility.</p> Signup and view all the answers

    What is the primary purpose of the plasma membrane?

    <p>To control the passage of substances into and out of the cell</p> Signup and view all the answers

    Which of the following body systems plays a crucial role in obtaining oxygen and eliminating carbon dioxide to maintain homeostasis?

    <p>Respiratory system</p> Signup and view all the answers

    What is the primary function of the integumentary system in maintaining homeostasis?

    <p>Serves as an outer protective barrier</p> Signup and view all the answers

    Which of the following is an example of an intrinsic control system?

    <p>Exercising skeletal muscle consumes more oxygen</p> Signup and view all the answers

    Which of the following factors is NOT a parameter that is tightly regulated to maintain homeostasis?

    <p>The size of the heart</p> Signup and view all the answers

    Which of the following body systems is responsible for breaking down dietary food into small nutrient molecules?

    <p>Digestive system</p> Signup and view all the answers

    What is the primary function of the endocrine system in maintaining homeostasis?

    <p>Regulates activities that require duration</p> Signup and view all the answers

    Which of the following is NOT a function of the nervous system in maintaining homeostasis?

    <p>Removes and eliminates wastes from the plasma</p> Signup and view all the answers

    What is the primary function of the reproductive system in maintaining homeostasis?

    <p>Perpetuation of the species</p> Signup and view all the answers

    Which of the following is NOT a component of the internal environment?

    <p>Digestive enzymes</p> Signup and view all the answers

    What is the primary function of the internal environment?

    <p>To facilitate exchange between cells and the external environment</p> Signup and view all the answers

    What percentage of body weight is comprised of extracellular fluid (ECF)?

    <p>20%</p> Signup and view all the answers

    Which of the following is an example of transcellular fluid?

    <p>Cerebrospinal fluid</p> Signup and view all the answers

    What is the term for the state of constancy of conditions within the body?

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

    What is the primary function of the epithelial tissue layer?

    <p>To separate the internal and external environments</p> Signup and view all the answers

    What is the term for the fluid environment in which cells live?

    <p>Extracellular fluid</p> Signup and view all the answers

    Which of the following is NOT a component of the extracellular fluid?

    <p>Intracellular fluid</p> Signup and view all the answers

    What is the primary source of energy used to drive secondary active transport?

    <p>Sodium ion gradient</p> Signup and view all the answers

    Which type of transport protein carries two substances across the membrane in opposite directions?

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

    What is the clinical application of Digitalis in relation to heart function?

    <p>Increases the force of heart contraction</p> Signup and view all the answers

    What is the process by which a vesicle fuses with the cell membrane to release its contents?

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

    What is the term for the movement of substances into a cell through a vesicle?

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

    What is the name of the disease caused by a defective gene that produces an abnormal chloride ion transporter?

    <p>Cystic fibrosis</p> Signup and view all the answers

    What is the term for the pressure of a solution that is proportional to the concentration of the solute particles that cannot cross the membrane?

    <p>Osmotic pressure</p> Signup and view all the answers

    What is the term for the process by which a cell engulfs a solid particle, forming a vesicle?

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

    What type of proteins act as cellular recognition sites, binding to specific substances?

    <p>Receptor proteins</p> Signup and view all the answers

    Which of the following is a characteristic of the lipid bilayer portion of the plasma membrane?

    <p>Permeable to small, nonpolar, uncharged molecules but impermeable to ions and charged or polar molecules</p> Signup and view all the answers

    What is the primary function of aquaporins in the plasma membrane?

    <p>To function as water channels, increasing the permeability of the membrane to water</p> Signup and view all the answers

    What is the main difference between primary active transport and other types of transport mechanisms?

    <p>It uses energy from ATP to pump substances across the membrane</p> Signup and view all the answers

    What is the primary purpose of the sodium/potassium ion pump in cells?

    <p>To maintain a low concentration of Na+ and a high concentration of K+ in the cytosol</p> Signup and view all the answers

    What is the term for the movement of solutes against a concentration gradient, requiring energy from ATP?

    <p>Active transport</p> Signup and view all the answers

    What is the purpose of linker proteins in cells?

    <p>To anchor proteins in the cell membrane or to other cells, allowing cell movement and maintaining cell shape and structure</p> Signup and view all the answers

    What is the term for the movement of macromolecules across the plasma membrane?

    <p>Vesicular transport</p> Signup and view all the answers

    Study Notes

    Introduction to Physiology

    • The course covers the cellular level of organization in the human body
    • References include Tortora and Derrickson's "Principles of Anatomy and Physiology" and Guyton's "Textbook of Medical Physiology"

    Parts of a Cell

    • A cell can be divided into three principal parts: plasma membrane, cytoplasm, and nucleus
    • Cytoplasm consists of cytosol and organelles (except for the nucleus)

    The Plasma Membrane

    • The plasma membrane is a flexible, sturdy barrier that surrounds and contains the cytoplasm of the cell
    • The fluid mosaic model describes the membrane as consisting of proteins in a sea of lipids
    • The lipid bilayer is the basic framework of the plasma membrane, made up of phospholipid molecules with cholesterol and glycolipids scattered among them

    Membrane Proteins

    • Proteins that stretch across the entire bilayer and project on both sides of the membrane are termed transmembrane proteins
    • Glycocalyx is a sugary coat facing the extracellular fluid, composed of glycolipids and glycoproteins
    • Glycocalyx enables cells to recognize one another and adhere to each other in some tissues, and protects cells from being digested by enzymes in the extracellular fluid

    Functions of Membrane Proteins

    • Formation of channels that allow specific substances to pass through
    • Transporter proteins that bind to specific substances, change shape, and move them across the membrane
    • Receptor proteins that act as cellular recognition sites
    • Enzymes that speed up reactions
    • Linker proteins that anchor proteins in the cell membrane or to other cells, allowing cell movement, shape, and structure
    • Cell identity markers that allow cells to recognize other similar cells

    Membrane Permeability

    • Plasma membranes are selectively permeable, allowing certain substances to pass through while keeping others out
    • The lipid bilayer is permeable to small, nonpolar, uncharged molecules but impermeable to ions and charged or polar molecules
    • The membrane is also permeable to water, with aquaporins functioning as water channels
    • Transmembrane proteins can increase the permeability of the membrane to certain molecules
    • Macromolecules are unable to pass through the plasma membrane except by vesicular transport

    Gradients Across Membranes

    • Concentration gradients exist across membranes, with higher concentrations of certain substances on one side and lower concentrations on the other
    • Electrical gradients also exist, with differences in electrical charge across the membrane

    Transport Across the Plasma Membrane

    • Active transport is an energy-requiring process that moves solutes against a concentration gradient
    • Primary active transport uses energy from ATP to pump substances across the membrane, such as the sodium/potassium ion pump
    • Secondary active transport uses energy stored in concentration gradients to drive other substances against their own concentration gradients
    • Osmosis is the movement of water from an area of high concentration to an area of low concentration through a selectively permeable membrane
    • Tonicity refers to the ability of a solution to cause a cell to swell or shrink

    Clinical Applications

    • Cystic fibrosis is caused by a defective gene that produces an abnormal chloride ion transporter, affecting various bodily systems
    • Digitalis slows the sodium ion-calcium ion antiporters, allowing more calcium to stay inside heart muscle cells and increasing the force of their contraction

    Transport in Vesicles

    • Materials can enter or leave the cell through vesicle transport
    • Endocytosis is the process of bringing materials into the cell, while exocytosis is the release of materials from the cell

    Plan of Human Body

    • The human body consists of an external environment and internal environment
    • The internal environment is the fluid surrounding cells inside the body, also known as the extracellular fluid (ECF)

    Body Fluids

    • Body fluids consist mostly of water
    • The ECF is the internal environment, surrounding cells inside the body
    • Body fluids contain ions, oxygen, nutrients, and waste products

    Fluid Compartments

    • The body has two main fluid compartments: extracellular fluid (ECF) and intracellular fluid (ICF)
    • The ECF is divided into plasma, interstitial fluid, and transcellular fluid
    • The ICF is the fluid contained within all body cells

    Homeostasis

    • Homeostasis is the maintenance of a dynamic steady state of the internal environment
    • Homeostasis is essential for cell survival
    • Factors that are homeostatically regulated include nutrient molecule concentration, gas concentrations, waste product concentration, pH, electrolyte concentration, body fluid volume and vascular pressure, and body temperature

    Human Body Systems Contribute to Homeostasis

    • Various body systems contribute to homeostasis, including the circulatory, digestive, respiratory, urinary, skeletal, muscular, integumentary, immune, nervous, and endocrine systems
    • Each system plays a specific role in maintaining homeostasis, such as transporting materials, breaking down food, obtaining oxygen, removing waste, providing support and protection, and regulating activities.

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    The Cellular Level Of Organization PDF

    Description

    This quiz covers essential concepts from the field of physiology, focusing on the cellular level of organization and the components of a cell. It is based on key references including Tortora and Derrickson's 'Principles of Anatomy and Physiology' and Guyton's 'Textbook of Medical Physiology'. Test your understanding of the fundamental mechanisms of body function.

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