Blood: Body Fluids, Plasma and Erythrocytes PDF

Please sign in, all, and collect a corrected schedule and term list. Syllabi and Review Sheets are also available BIO 164 / A&P II for those who missed Monday's class. Dr. Dornhoff To fill in on index cards (i...

Please sign in, all, and collect a corrected schedule and term list. Syllabi and Review Sheets are also available BIO 164 / A&P II for those who missed Monday's class. Dr. Dornhoff To fill in on index cards (if not done on Monday): - Your name (including nicknames) - Contact information (phone, LCCC email, other preferred email) - Program goals / career pathway - Grade in A&P I - Past chemistry courses? - Concerns about course, if any (workload, tech issues, etc) Body Fluids, Plasma and Erythrocytes Every living cell in the body needs the same basic resources - oxygen, fuel, a way to dispose of byproducts - if it's to obtain energy via cellular respiration. However, only certain organs have direct access to these resources, and none have direct access to all. How can the body ensure that cells obtain necessary resources to meet their energy needs, no matter how far away they might be located from the lungs, intestines, or kidneys...? Blood: Our built-in delivery service - Our only actively-propelled, free-flowing body fluid - Transport medium for solutes, water and heat - Contains multiple components suspended in watery plasma: * Plasma proteins (all kinds) stabilize osmotic balance * Erythrocytes and carrier proteins facilitate transport * Leukocytes and antibodies fight infections * Platelets and fibrinogen perform hemostasis - Blood types are dictated by cells' surface composition A hematocrit test demonstrates the multiple components of blood. ~12% of body's fluid Also the most active kind Plasma is much more complex than other body fluids (CSF, endolymph, mucus, etc) because it performs dozens of functions at once. Where are our body fluids, and why is plasma such a busy one? Intracellular Fluids Extracellular Fluids Body Water Content Infants: 73% or more water (low body fat %, less calcified skeleton) Adult males: ~60% water (higher muscle mass) Adult females: ~50% water (higher body fat %) Water content declines to ~45% in old age 3 liters = ~8.5 Adipose is "driest" tissue, compact bone is second Muscle, blood, loose fibrous types are water-rich soft drink cans Interstitial = "in the gaps between" Interstitial fluid, aka Tissue fluid Interstitium = All the gaps it's in! Fluid Compartments Total body water = ~40 L for average adult Two main fluid compartments Intracellular fluid (ICF) compartment: liquids in cells Extracellular fluid (ECF) compartment: liquids outside cells Plasma: 3 L in heart & blood vessels Interstitial fluid (IF): 12 L in spaces between cells Some fraction of the IF is also known as Transcellular Fluid (TF): lymph, CSF, humors of the eye & ear, synovial fluid, serous fluid, mucus, gastrointestinal secretions Blood plasma conveys resources ​to the interstitial fluid from their ​source organs, and waste products ​from IF to organs of elimination. Individual cells absorb what they need from the IF and release their wastes into it, keeping their own intracellular fluid chemically stable while obtaining vital resources. Plasma and interstitial fluid are ​chemically similar due to constant ​exchange/free mixing. - High in Na+, Cl-, HCO3- - Low in K+, Mg2+, HPO42- - Plasma has more proteins Intracellular fluid only exchanges ​materials under the cell's control, ​so it can maintain a very different mix of high and low solutes. A&P I Recap: Remember Na+ and K+ from your lessons about action potentials? Lots of K + inside cells, lots of Na+ outside them! What's in plasma, and what do its chemical components do? Solvent for dissolved materials; transport medium; absorbs and distributes thermal energy All kinds: maintain osmotic pressure Mineral resources; ions for excitation of tissues; buffers for pH regulation Contribute to viscosity of blood; most facilitate lipid transport Transport lipids, calcium, other solutes; buffer for blood pH Alpha: Copper & hemoglobin transport; triggering coagulation Beta: Iron transport; defense globulin Antibodies that fight infection Coagulants for blood clotting Products of ammonia from ​using amino acids as "fuel" Fuel & building materials necessary for our cells O2 & CO2 (cellular respiration!) Communication by ; others flow free endocrine system Lack of dietary protein plasma protein production shuts down. Albumin and globulin levels fall. Osmotic imbalance causes water to leave plasma and seep into ventral body cavity. Kwashiorkor  Formed elements of blood - Whole or incomplete cells - Nearly all generated in bone marrow - Derived from hemopoietic stem cells Erythrocytes ~45% of whole blood Leukocytes & platelets = "buffy coat" ~1% of volume of whole blood Other ~55% is plasma The most plentiful of formed elements are erythrocytes, aka "red blood cells". Biconcave disc Lacks a nucleus Flexible & stackable ("stack") Very small even ​by cell standards Small size, round shape, and ability to stack let erythrocytes pass easily through capillaries. About 1/4 of your cells This allows them to reach practically ​are erythrocytes. every cell that needs O 2 delivered or ​That's 20-30 trillion! has CO2 to get rid of. Medical fact: "Red blood cell" is a nickname and convenience for abbreviation (RBC), not the official term for these cells. Make a habit of calling them by their proper name!  Hemoglobin: Erythrocytes' gas- carrying protein molecule Polypeptide chains (2&2) can hold 2 CO2 total Heme groups (4) can ​hold one O2 each 250 million hemoglobins per RBC ~6.25 billion trillion in whole body! Iron (Fe) loosely connects to oxygen molecules long enough for transport  Iron (Fe) within the heme groups loosely binds to O2 and turns oxygen-rich blood bright crimson. Blood's color turns to maroon after this O2 is released from iron and out into the interstitial fluid.  Erythrocytes are produced in the red bone marrow. Erythropoiesis Finished cell ​has life span Generates ribosomes to make ​of ~4 months lots of hemoglobin Hemocytoblast, aka Ejection of nucleus ​lightens the load Migrates from red Parent stem cell for ​all formed elements Daughter cell that's Hemoglobin construction (anabolism!) marrow to blood ​assigned the job of turns cell from ribosomes' blue to red ​erythrocyte A&P I Recap: Remember how cells that build things in bone or fibrous tissues have names that end in "-blast"? Osteoblast, fibroblast... and now, erythroblast and hemocytoblast!  Action of Erythropoietin (EPO) RBC production (erythropoiesis) ​must keep up with how rapidly the erythrocytes wear out and/or are lost to injury, menstruation, etc. Having too few properly-working erythrocytes is anemia, which can arise in many ways. It limits rates of O2-delivery by blood, impacting all of our energy-using tissues' metabolism. But, making too many erythrocytes (polycythemia) will make blood too thick/viscous to flow easily, raising the BP and straining the heart and blood vessels. Erythrocyte Life Story, Pt. 1 1) Raw materials for hemoglobin are conveyed by plasma proteins (= transferrin) from gut to red marrow. 2) Hemopoietic stem cells are stimulated by EPO to produce new erythrocytes. 3) Constant circulation wears away at RBCs, which cannot self-repair without a nucleus to direct the process. Erythrocyte Life Story, Pt. 2 4) Worn-out erythrocytes are "recycled" in the spleen, liver, or red marrow, whichever they pass through first. 5a) Pieces of erythrocyte plasma membrane are consumed by macrophages and broken down for lipids, etc. 5b) Hemoglobins' polypeptide chains are catabolized for 5c) Heme groups' iron amino acids. is recycled, while the rest is degraded into bilirubin and excreted in feces. 6) Reclaimed iron is used for new hemoglobins, or for muscles' myoglobin. Some possible causes of RBC deficiency & anemia: - Genetically-slow rate of production (e.g. erythropoietin deficiency) - Accelerated rate of destruction (e.g. hemolytic anemia) - Genetically-faulty RBCs produced (e.g. thalassemia) - Genetically-faulty hemoglobin produced (e.g. sickle-cell anemia) - Dietary iron deficiency - Temporary iron deficiency due to bleeding injury or menstruation - Impaired hemoglobin function (e.g. carbon monoxide poisoning) In sickle-cell anemia, ​hemoglobins with no attached O2 may adhere to one another, not just to CO2. They form long chains that press on the plasma membrane until the cell folds over into a "sickle". Blood (recap): - Our only propelled, free-flowing body fluid - Transport medium for solutes, water and heat - Plasma proteins stabilize osmotic balance - Erythrocytes and carrier proteins facilitate transport - Leukocytes and antibodies fight infections [For Monday & Unit II] [Mostly for Unit II] - Platelets and fibrinogen perform hemostasis Blood typing [For Monday]  Next time, we'll next look at blood's "buffy coat" parts, as well as what blood types are and how they work. Lightweight plasma rises to surface "Buffy coat" of medium- weight WBCs & platelets Weight of hemoglobin brings RBCs to bottom Starting next Wednesday, we'll introduce the heart and vessels that carry blood.