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Assignment-11.Discuss the importance of body fluids and which one is considered the body’sinternal environment. (4 marks) 1.4The major fluid compartments in the body comprise of intracellular fluid compartment(ICF) that occupies about two-thirds is in the volume and intracellular fluidextracellular fluid compartment (ECF). ECF occupies about one-third of bodywater and lies outside the cells. The ECF is the body’s internal environment and thecells external environment. The ECF compartment is in two compartments: (i)Plasma, the fluid portion of blood, and (2) interstitial fluid (IF), the fluid in thespaces between tissue cells. ECF differs depending on where it occurs in the body.ECF within blood vessels is blood plasma, within lymphatic vessels it is calledlymph, in and around the brain and spinal cord it is known as cerebrospinal fluid, injoints it is referred to as synovial fluid, and the ECF of the eyes is called aqueoushumor and vitreous body. The proper functioning of body cells depends on aprecise regulation of the composition of the interstitial fluid surrounding them.Because of this, interstitial fluid is often called the body’s internal environment.The composition of interstitial fluid changes as sub- stances move back and forthbetween it and blood plasma. Such exchange of materials occurs across the thinwalls of the smallest blood vessels in the body, the blood capillaries. Thismovement in both directions across capillary walls provides needed materials, suchas glucose, oxygen, ions, and so on, to tissue cells. It also removes wastes, such ascarbon dioxide, from interstitial fluid. It transports nutrients to organs in the body.It regulates the body temperature. Acts as a lubricant between joints in the bone.2.Describe the three major types of lipids found in the body. (6 marks) 2.5oFatty acids: Used to synthesize triglycerides and phospholipids or catabolized to generateadenosine triphosphate (ATP) oTriacylglceride (fats and oils): These are composed of fatty acids, which can be in thesaturated (single covalent bonds) form or the unsaturated (one or more double covalentbonds) form and a glycerol backbone. The presence of either unsaturated fats or saturatedfats determine whether a triglyceride will be fluid or solid at room temperature.Triglycerides with only saturated fatty acids will be a solid at room temperature.1
Triglycerides with one (monounsaturated fat) or multiple unsaturated fatty acids(polyunsaturated fat) will be a fluid (oil) at room temperatureoPhospholipids are important structural components of the membranes of cells. Themajority of membrane phospholipids have a glycerol backbone to which are attached thefatty acyl chains, as well as an alcohol linked to glycerol via a phosphate group3.Describe briefly, what is occurring at each step in the figure. (3 marks) 3.6Following are the stages: oFig-1: Procurement of basic materials such as nutrients and elements for furtherdevelopmentoFig-2: Formation of a cell utilizing the elements and nutrientsoFig-3: Insertion of genetic materialoFig-4: Conjugation phase to acquire the properties of new genetic materialoFig-5: Leaving the existing genetic material2
oFig-6: Moving of new genetic material to perform the functions of cell4.Name and briefly describe the cell shapes, arrangements, and functions of celllayers found in epithelial tissues. (3 marks) 3.8Following are the different types of cells found in epithelial tissueoSimple squamous: These cells are present as flat without layers and involving in diffusionprocess (of gases) E.g., cells present in lung alveoli type-1 oStratified squamous: These cells present as flat shaped in layers. The main function ofthese cells is to resist abrasion and friction E.g., cells of linings of mouth, esophagus andtongueoSimple columnar: Column shaped cells without layers, perform the functions ofabsorption E.g., cells of small intestine and stomachoStratified columnar cells: Columnar shaped cells present as layers. Perform secretion andprotection functions E.g., pharynx and anusoSimple cuboidal cells: Cubic shaped cells; occur as layers and perform secretion functionE.g., cells of kidneysoStratified cuboidal cells: Cuboidal cells present in layers. Perform secretion functionsE.g., salivary glandsoTransitional cells: Transitions from columnar cells to squamous depending on fluidexerting pressure on them and perform elimination function E.g., cells present in bladder,ureter, and urethra oPseudo stratified columnar cells: Possess look up shape. Hard to describe, present inupper respiratory tract.5.Describe the structural characteristics of the epidermis that relate to itsprotection function. Compare thick to thin skin. (6 marks) 4.4The structural characteristics of the epidermis as follows towards protection function oMultiple layers of cells in stratified squamous epithelium help resist friction. oKeratin of intermediate filaments provides strength to tissue by binding cells tightlytogether and to underlying tissue, and by producing a barrier to microbes. oLamellar granules of keratinocytes produce a lipid-rich, water-repellent sealant to protectfrom dehydration and the entry of foreign materials. 3
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