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Summary BBS1002 Homeostasis and Organ Systems
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Summary of 31 pages for the course BBS1002 - Homeostasis And Organ Systems at UM (-)
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Summary homeostasis and organ systems BBS1002Case 1
Blood = connective tissue, consist of two elements
1) Plasma clear extracellular fluid
2) Formed elements erythrocytes (RBCs), leukocytes (WBCs) and platelets
Composition of plasma:
Functions of plasma proteins
o Reserve supply of amino acids for cell nutrition macrophages
break them down
o Carrier for other molecules function as weak base by binding H +
o Protection against blood loss and invasion by foreign
microorganisms and viruses by interacting in specific ways which
cause the blood to coagulate
o Govern distribution of water between blood and tissue by creating osmotic pressure
Types of plasma proteins
Albumins helps substances dissolve by binding, plasma transport
o Fibrinogen forms framework of blood cloth
o Globulins alpha, beta and gamma
High density lipoproteins (HDL): lipid transport, membrane reconstruction,
hormone function, prevent cholesterol invasion and setting
Low density lipoproteins (LDL): carries cholesterol and fats to tissues for
manufacturing steroid hormones, favors deposition of cholesterol
Amino acids
Nitrogenous waste excreted by the kidneys
Nutrients absorbed by the GI tract
Gases oxygen and carbon dioxide, dissolved nitrogen
Electrolytes blood’s osmolarity
Red blood cells (RBCs)
Two main functions:
1. Pick up oxygen in the lungs and deliver it to the tissues
2. Pick up carbon dioxide in the tissues and deliver it to the lungs
Disc shaped with a sunken center
o Membrane: glycolipids and -proteins, which determine your blood type
o Inner membrane surface: spectrin and actin resilience and durability
Almost no cellular components no aerobic respiration, not use the oxygen they carry
o No nucleus, so no self-repair
Cytoplasm 33% sol. Hgb, which causes the red color
Life span approx. 120 days
White blood cells (WBCs)
Granulocytes
o Neutrophils: polymorphonuclear variety of nuclear shapes, destruction of bacteria
and the release of chemicals that kill bacteria
o Eosinophils: destruction of allergens and inflammatory chemicals, release enzymes
that disable parasites
o Basophils: secrete histamine which increases blood flow, secrete heparin which
prevents clothing so increased mobility
Agranulocytes
, o Lymphocytes: destroying cancer cells, cells infected by viruses and foreign invading
cells, activate other immune system cells by presenting antigens, coordinate these
cells, secrete antibodies, immune memory
B-cells: produced in bone marrow, produce large quantities of antibodies
T-cells: produced in bone marrow but matured in thymus
T-helper: produce cytokines
Cytoxic T (T-killer): produce toxic granules which induce the death of
pathogen infected cells
Platelets
Secrete vasoconstrictors spasm in broken blood vessel prompt constriction which
protects against blood loss until other mechanisms take over
Form platelet plugs: draw the walls of a blood vessel together by adhering to other platelets
Secrete procoalugants which help in blood clothing by turning fibrinogen into fibrin
Dissolve blood cloths
Digest and destroy bacteria
Secrete chemicals that attract neurophils and monocytes to sites of inflammation
Secrete growth factors to maintain the lining of blood vessels
Transport mechanisms of blood
Cardiovascular system pulmonary circulation and
systemic circulation
Capillary exchange
o Gases, lipids and lipid soluble molecules can
diffuse directly through membranes
o Glucose, amino acids and ions use transporters
facilitated diffusion
o Larger molecules pass through pores
o Water moves by osmosis
Bulk flow = the movement of fluids
o Hydrostatic pressure drives filtration
Pressure of any fluid in a space
Capillary hydrostatic pressure drives
fluid out of capillaries into the tissues
Interstitial fluid pressure: opposing
hydrostatic pressure is usually lower
than CHP due to lymphatic vessels
the fluid moves out of the capillaries into the lymphs
o Osmotic pressure drives reabsorption
Driven by osmotic concentration gradients
Plasma proteins play the main role
BCOP is always higher than IFCOP, because some molecules cannot pass to
the IF, so the water with dissolved molecules travels into the bloodstream
Production of different blood cells
, Hemopoiesis = production of the formed elements
o Embryo yolk sac, fetus bone marrow, liver, spleen and thymus, during birth
liver stops, right after birth spleen stops, infancy onwards bone marrow
Hemocytoblast proerythoblast erythoblast normoblast reticulocyte erythrocyte
Hemocytoblasts
o B progenitors B lymphocytes
o T progenitors T lymphocytes
o Granulocyte-macrophage colony-forming units granulocytes and macrophages
Case 2
Structure of the heart
Microscopic: three layers
1. Epicardium
outer, protective
layer
o Inner layer
of
pericardium
o Mostly
loose
connective
tissue
o Protects
and assists
in
producing pericardial fluid fills pericardial cavity
o Coronary blood vessels, direct contact with myocardium
2. Myocardium muscular, middle layer
o Cardiac muscle fibers cause the contractions
o Thicker at the left ventricle
o Contractions regulated by the peripheral nervous system bundle of His an
Purkinje fibers
, 3. Endocardium inner layer
o Lines heart chambers, covers valves, continuous with endothelium of blood vessels
o Atria: smooth muscle and elastic fibers
Valves are a flap of connective tissue
Heart contraction
Electrical impulses:
1. Action potential is generated in the SA node
2. Travels through fibres in the atria which contract. Bachmann’s bundle conducts the impulses
directly from the right to the left atrium, so that they contract at the same time
3. Travels through the right atria to the AV node, where it is delayed slightly to allow relaxation
of the ventricles and passive filling
4. Travels along the Bundle of His left and right bundle branch form the interventricular
septum
5. To the walls of the ventricles by Purkinje fibres
6. Ventricles contract and impulses travel towards the atria
Pacemaker cell Cardiomyocyte
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