6 Pages
Unlock Document

University of Toronto Scarborough
Biological Sciences
Maydianne Andrade

1 Lecture 11 The Cardiovascular System: Heart and Blood Introduction The cardiovascular system functions as a system to transport numerous substances throughout the body such as: nutrients, oxygen and carbon dioxide, hormones and ions Transports metabolic wastes to the kidneys Transports leukocytes (white blood cells) to aid in fighting infectious agents Composition of the Blood Whole blood 4-6 liters Blood consists of two components Plasma - liquid matrix of blood Formed elements: blood cells and cell fragments that are suspended in the plasma, and include: Erythrocytes (red blood cells): transport oxygen and carbon dioxide Leukocytes (white blood cells): function in the immune system Platelets: involved in blood clotting Plasma (mostly fluids) - makes up about 55% of the volume of whole blood Consists of: 92% water 7% proteins (albumin, globulins, fibrinogen, regulatory proteins) 1% other solutes (electrolytes, organic nutrients, organic waste) Plasma proteins: there are three major classes of protein in the blood (of the 7% of proteins) 60% Albumin – contributes to the osmotic pressure, transports fatty acids and steroids, smallest of the proteins 35% Globulins - act as immunoglobulins (antibodies) and act as transport proteins (transport ions and hormones) 4% Fibrinogen - involved in blood clotting, largest of the proteins Formed elements (different types of cells + platelets) - makes up about 45% of whole blood Platelets (<0.1% of formed elements) Leukocytes (White Blood Cells WBC) (<0.1% of formed elements) Neutrophils (50–70% of the WBCs) Eosinophils (2–4% of the WBCs) Basophils (<1% of the WBCs) Lymphocytes (20–30% of the WBCs) Monocytes (2–8% of the WBCs) Erythrocytes (Red Blood Cells RBC) (99.9% of formed elements) Red Blood Cells (RBCs) or Erythrocytes Structure of RBCs Biconcave disc – means they are concave on both sides (they have 30% more surface area than a sphere would have so biconcave increases the surface area) Thin central region Measure about 7.7 microns in diameter Lack cell organelles Lack a nucleus (anucleated) RBC Life Span Since RBCs lack a nucleus and all the organelles, have a life span of about 120 days (because they don’t reproduce, they stay in the blood for 4 months) 2 - They are made from stem cells (that can only make blood cells) from the bone marrow that is omnipotent (?) Significance of a lack of a nucleus: Allows the cell to be flexible as it travels through the circulatory system Allows for more room for hemoglobin Significance of a lack of mitochondria: Mitochondria use oxygen to manufacture ATP Without mitochondria, oxygen can be transported to the tissues instead of being “used” by the mitochondria RBCs and Hemoglobin A developing erythrocyte loses its nucleus and organelles A mature erythrocyte is mainly a cell membrane surrounding water and protein The water accounts for 66% of the RBC’s volume The protein accounts for 33% of the RBC’s volume of which >95% is hemoglobin Hemoglobin is responsible for transporting oxygen and carbon dioxide (the main function of RBCs) Hemoglobin Consists of four polypeptide subunits Each subunit contains a molecule of heme Heme is a porphyrin ring Each heme consists of an iron ion Iron binds to oxygen The polypeptide units bind to carbon dioxide Oxygen and carbon dioxide do not compete with each other for binding sites Leukocytes or White Blood Cells (WBCs) White blood cells make up less than 1% of the blood cells There are two major classes of leukocytes consisting of a total of five major types of leukocytes Granulocytes: neutrophils, eosinophils, basophils Agranulocytes: monocytes, lymphocytes WBCs have a short life span (usually a few days) When the body is compromised, the white blood cells multiply to combat the invading agent or allergen, etc. Granulocytes Neutrophils (normal range is 50–70%) Granules contain chemicals to kill bacteria Typically the first WBC at the bacterial site Very active phagocytic cells Nucleus is multilobed- polynucleus ( made of lots of little nuclei • Do not react to the stains very strongly (very neutral color (lilac)) • More for helping allergic reactions Eosinophils (normal range is 2–4%) Granules release chemicals that reduce inflammation Attack a foreign substance that has reacted with circulating antibodies (such as an allergic reaction or parasites) Typically have a bilobed nucleus • React to the eosine stain • More for allergic reactions Basophils (normal range less than 1%) Granules release histamine and heparin 3 Histamine dilates blood vessels Heparin prevents abnormal blood clotting Nucleus is usually hidden due to all the granules • React to the hemotoxylin stain • More for allergic reaction Agranulocytes Monocytes (normal range is 2–8%) Large phagocytic cells Release chemicals to attract other phagocytic cells Release chemicals to attract fibroblasts Fibroblasts produce collagen fibers to surround an infected site These collagen fibers can produce scar tissue Nucleus is kidney-shaped or large oval-shaped • More helpful for wound healing Lymphocytes (normal range is 20–30%) Responsible for specific immunity Can differentiate to form T cells, B cells, and NK cells Nucleus is typically large and round leaving a small halo around the entire nucleus or part of it T cells - attack foreign cells directly (T means they mature in the thymus) B cells - antibodies to attack foreign cells (B means they mature in the bone marrow) NK cells - Responsible for immune surveillance- attack any type if affected tissue etc. Platelets (used to be called flambocytebut they are not really cells; they are fragments of megakaryocytes) Usually part of the agranulocytes group. Derived from megakaryocytes Megakaryocytes will fragment forming bits and pieces of membrane- enclosed packets of chemicals The main chemical is platelet thromboplastin factor About 3
More Less

Related notes for BIOB33H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.