Lab 3 Quiz: Blood Sampling & Glucose Homeostasis

Purpose of blood sampling experiment?

to explore study designs and data interpretation, and to use quantitative methods to compare samples across population using the model of blood components.

What functions in the body does blood perform?

supply of oxygen, glucose, amino acids, and fatty acids to tissues. Removal of wastes such as carbon dioxide, urea, and lactic acids. Transport of hormones. Immunological functions including circulation of white blood cells and antibodies. Regulation of body pH and core body temperature.

What are blood tests used for?

to diagnose diseases, chemical imbalances, and organ function.

What is the total blood volume in an average adult?

4-5.5 liters, comprising about 7-8% of body weight.

What is blood composed of?

Plasma (water, ions, organic molecules, trace elements and vitamins, gasses) Cellular elements (red blood cells, white blood cells, platelets)

What are plasma proteins?

globulins (antibodies), albumin (fibrinogen), electrolytes (ions), nutrients, waste products, gases, and hormones.

What is the function of plasma?

serves as the fluid medium for transport of materials through the blood and is also important for absorbing and distributing heat, produced by metabolic processes, throughout the body.

What are the cellular elements of blood?

red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

What are erythrocytes?

flat, biconcave, disc-shaped cells that lack a nucleus, thus maximizing space for hemoglobin molecules. IN a healthy adult over 99% of the cells in the blood are erythrocytes.

What are hemoglobin molecules responsible for?

carrying oxygen from the lungs to the tissues, and some carbon dioxide from the tissues to the lungs.

What is erythropoiesis?

the production of erythrocytes, tightly regulated process that maintains erythrocyte levels (20-30x10^12 in the body) within a fairly narrow range. Regulated by the hormone erythropoietin.

In a steady state, how much erythrocytes are produced?

10^10 per hour in the bone marrow. This enormous rate is necessary because erythrocytes, which live 100-120 days are disappearing from the blood in the same large numbers every second.

What is erythropoietin?

a hormone synthesized by the adult kidney in response to hypoxia (decreased O2 in the blood- due to altitude or conditions affecting respiration).

What increases production of erythropoietin in the kidney?

hypoxia, androgens (male sex hormones such as testosterone)

What are leukocytes?

white blood cells, account for less than 1% of the blood in healthy adults but play a key role in the body's immune response to foreign invaders. Carry out functions in tissues.

What is leukocytosis?

the presence of elevated leukocytes in the blood, can indicate infection, inflammatory response, illness, leukemia, and many other clinical conditions.

What is leukopenia?

low leukocyte count, indicates a person may have immunodeficiency disease such as Acquired Immunodeficiency Syndrome (AIDS), an overwhelming infection, or is undergoing chemotherapy.

What are thrombocytes?

platelets, cellular fragments essential for controlling bleeding from an injured vessels through a process known as the coagulation cascade.

What is thrombocytopenia?

a low number of platelets in the blood, leads to problems with the formation of blood clots. Occurs for a variety of reasons including vitamin B12, folate or iron deficiency; certain viral infections; chemotherapy; excessive alcohol consumption; and pregnancy.

What is thrombocytosis?

a high platelet count, causes the blood to be thick and flow more slowly which can result in blood clots. Increases risk of heart attack or stroke. Caused from infections, inflammatory conditions, cancer, or not having a spleen.

What is the hematocrit?

the packed cell volume (PCV), represents percentage of erythrocytes in the total blood volume, referred to as hematocrit. Average is 42.5%.

What causes an increase in hemtocrit?

an condition that causes an increase in erythrocyte production or a decrease in plasma volume (e.g., dehydration, blood doping, living at a high altitude)

What is anemia?

results from decreased hematocrit, a condition causing a decrease in the oxygen-carrying capacity of blood. Three main causes- 1. blood loss, 2. decreased red blood cell production, 3. increased red blood cell breakdown

What does the different blood group you are in depend on?

surface markers, antigens, found on red blood cells. Blood group antigens are either surface carbohydrates or proteins attached to various components in the red blood cell membrane. Main two blood groups= ABO and Rh

What are the four blood types?

A, B, AB, or O. Occur as a result of the presence or absence of two antigens (antigen A or antigen B) on the surface of erythrocytes. Cell surface erythrocytes added by a series of enzymatic reactions. A persons DNA determines types of enzymes.

What are antibodies?

produced by the body (anti-A or anti-B) against the antigens NOT present on the surface of erythrocytes.

What antigen is present on the blood type O?

no A or B antigens, anti-A and anti-B

What antigen is present on the blood type A?

A antigens, anti-B

What antigen is present on the blood type B?

B antigens, Anti-A

What antigen is present on the blood type AB?

A and B antigens, none to A or B

What it the Rhesus (Rh) blood type?

in addition to ABO blood types, everyone has a Rh antigen on their surface. Either positive (Rh+) or negative (Rh-). Not a carbohydrate, a transmembrane protein. If you express the D antigen on the surface of your erythrocytes= Rh positive. If you do not express the D antigen on the surface of your erythrocytes= Rh negative.

What antibodies will a Rh negative individual produce?

anti-D antibodies

What antibodies will a Rh positive individual produce?

not make anti-D antibodies

How are anti-D antibodies produced?

when the body is exposed to the Rh antigen. For example, if a Rh negative mother encounters the Rh positive blood of her fetus during delivery, she will begin to produce anti-Rh antibodies. During subsequent pregnancies, the mother's anti-Rh antibodies will cross the placenta and bind to the Rh+ blood cells in the fetus leading to their destruction (hemolysis)

What are blood transfusions?

routine medical procedures that can help replace blood lost due to surgery or injury. Blood types must match.

What is agglutination?

when the wrong blood type is used, the antibodies in the plasma of the recipient will clump with the antigens on the surface of erythrocytes from the donor.

Where are the genes that are determined by blood type?

inherited from both parents. ABO is controlled by a single gene (the ABO gene) that encodes a glycosyltransferase.

What is a glycosyltransferase?

an enzyme that modifies carbohydrates, carbohydrates present on the surface of erythrocytes. ABO blood type determined by the type of glycosultransferase expressed in the body.

How does heritability of blood types work?

the ABO gene has three main alleles: A, B, and O. Each person inherits two ABO blood type alleles, one from his/her mother and one from his/her father. The A and B alleles are co-dominant (will be expressed if present) while the O allele is recessive (will not be expressed unless there are two copies present)

What could someone with the blood type A be in terms of genotype?

homozygous for the A allele (A,A) (inherited A from both mother and father), heterozygous with an A allele and an O allele (A,O)

What is the Rh blood type controlled by?

a single gene (RHD). Rh blood type is inherited as an autosomal dominant trait. Presence of the D antigen (Rh+) being dominant. Rh+= (+,+) or (+,-). Rh-= (-,-)

What is the purpose of the glucose homeostasis expiriment?

to perform a glucose tolerance test and explore glucose homeostasis, and to observe how your research question influences your choice of which statistical test to use and how to interpret your data.

What is a homeostatic control system?

a network of body components working to maintain a regulated variable relatively constant within an acceptable range around its setpoint. To do this, body needs to monitor the regulated variable and report any changes from the setpoint.

What is the pathway if the regulated variable deviates from setpoint?

Stimulus--> sensor--> input signal--> integrating center--> output signal--> effector (targt)--> response

What does the sensor do?

alters its activity to report changes in the regulated variable. Information carried via the afferent pathway to an integrator.

What is an integrator?

integrates information coming from other sensors (e.g., integrating information about both decreases and increases in regulated variable.

What happens if an adjustment signal is necessary?

carried via the efferent pathway to the effector (target), which brings about the desired physiological response (i.e., restores the regulated variable back towards its setpoint)

What is feedback control?

responses made after a change has been detected; feedfoward, negative feedback, positive feedback

What is feedforward control?

used for responses made in anticipation of a change

What is negative feedback?

a change in homeostatically-regulated variable triggers a response that acts to restore the regulated variable back towards its setpoint (i.e., in the opposite direction of its initial change)

What is positive feedback?

acts to enhance or amplify the change so the regulated variable continues to move in the same direction of the initial change. Non-homeostatic and less common.

What is tonic control?

there is a single controller regulating a physiological parameter in an up-down fashion (e.g., neural regulation of the diameter of some blood vessels). Like the volume control on a radio, the radio is always on but by turning a single knob you can make the sound level louder or softer.

What is antagonistic control?

uses two different controllers. Ex. the sympathetic branch of the ANS increases heart rate, whereas parasympathetic branch decreases heart rate.

What happens when blood glucose levels decrease?

alpha cells in the pancreas sense the change and release the hormone glucagon. Binding of glucagon to its receptor activates a cell signaling pathway that stimulated the breakdown of glycogen back into glucose through glycogenolysis. Glucose is then able to leave the liver cells and enter the blood via facilitated diffusion using (GLUT) transporter to restor blood glucose levels.

What does glucagon do?

leads to an increase in blood glucose levels by binding to glucagon receptors in liver cells.

What happens when blood glucose levels increase?

beta cells in the pancreas sense the change and release the hormone insulin. When insulin binds to its membrane receptor on these target tissues, a signal transduction cascade is activated. This causes (GLUT) transporter proteins (stored in secretory vesicles) to be moved out of the cell membrane of these tissues. Glucose then leaves the blood and enters the tissues via facilitated diffusion.

What does insulin do?

leads to a decrease in blood glucose levels by binding to insulin receptors in the liver, muscles, and adipose tissue.

What is hyperglycemia?

only a small amount of glucose can cross the cell membrane via GLUT in insulin-dependent tissues. This low rate of transport results in higher than normal blood glucose levels. Common cause includes diabetes mellitus (produces either abnormal insulin secretion or responsiveness)

How is glucose that is filtered into the kidneys reabsorbed?

via the sodium-glucose linked transporter (SGLT) present in the epithelial cells of the kidney. If the concentration of glucose exceeds the transport maximum of the SGLT, all the glucose binding sites on the SGLT are occupied and the transporters are saturated.

Glucosuria

glucose that remains in urine

What is polyuria?

excessive urination

What is polydipsia?

excessive thirst

What is stress hypergylcemia?

refers to a temporary elevation of the blood glucose due to the stress of an illness. Usually resolves spontaneously.

What is hypoglycemia?

decreased blood glucose levels, symptoms include weakness, tremors, hunger, and irritability, causes include medications, excess alcohol consumption, disorders affecting liver heart or kidneys.

What is hyperinsulinemia?

excessive insulin

What is a oral glucose tolerance test (OGTT)?

preformed clinically to assess the ability of the body (especially cells of the pancreas) to respond to an excess ingestion of glucose (usually 75 grams of glucose solution)

In a clinical OGTT, what should normal fasting blood glucose levels be?

Between 70-110mg/dl. Above 126 mg/dl= diabetes

What factors can impact glucose tolerance?

impaired glucose tolerance or diabetes, food consumption, exercise, stress, and certain medications.