part 1 Flashcards
What is Physiology?
The study of living function.
About how many cell do humans have?
75 Trillion
What is Homeostasis?
Maintenance of constant conditions within the body.
What does it mean to function as an automaton?
The vast Majority of operations are carried out by automatic control systems.
Physiology sometimes is thought of as the study of _______ systems.
Control
What is the more typical approach to control systems?
Negative feedback
Negative feedback involves what type of a response?
Negative
The negative feedback consists of what?
A sensor and an output system.
Negative feedback is like what system in a house?
The furnace. It is an on/off system
Homeostasis is a _____ balanced state of self-regulation.
Dynamically
For negative feedback the degree of effectiveness of the control is a function of what?
The “Gain” of the feedback system.
Negative feedback system leads to what?
Homeostatic stability.
How common is positive feedback and it leads to what?
Uncommon and leads to instability.
Positive feedback involves what type of response?
In the Positive or same direction.
Positive feedback leads to what?
a vicious cycle that circles until death.
When is positive feedback helpful?
in short-term situations like blood clotting and action potentials.
What does thrombocytopenia mean?
Low levels of platelets.
Idiopathic thrombocytopenia purpura is what type of disorder?
One of decreased platelet numbers. normal platelet numbers 200,000-400,000 down to 50,000 or less.
what are the 2 versions of idiopathic thrombocytopenia purpura?
Childhood version that seems to self-resolve Adult version needs ongoing therapy.
What are the signs of idiopathic thrombocytopenia purpura?
easy bleeding micro-bleeds easy brusing nosebleeds
What are the laboratory findings of idiopathic thrombocytopenia purpura?
Prolonged bleeding times anemia may develop deficient clot retraction.
What type of fluid is blood?
A transportation fluid.
What color is oxygenated and deoxygenated blood?
oxygenated = brighter red deoxygenated = darker red
What is the specific gravity of blood?
1.050 g/ml
What is the ph and temperature of blood?
ph= 7.4 temp = 37 c or 98.6 f
How much more viscous is blood than water?
3-5 times more.
How much blood does the average person have?
5 liters 7.75% of body weight.
What % of blood is Plasma, WBC with platelets, and RBC?
Plasma= 55% WBC with platelets= very little RBC= 45 %
What is the thin veneer in the middle of a test tube of seperated blood called and made of?
Buffy coat made of Leukocytes and platelets.
The erythrocytes make up 45 % of the blood in a test tube and the volume of rbc in blood is known as?
Hematocrit
What are the specific values for Hematocrit?
5,000,000 +- 500,000 per mm3
A decreased hematocrit is indicative of what?
Anemia
You are considered anemic with a hematocrit count of how low?
4 million of lower
An increased hematocrit is indicative of what?
Polycythemia.
What is polycythemia?
A high amount of RBC.
What is the hematocrit count for polycythemia?
6 million or more.
Extreme polycythemia can result in what?
An interrupted blood flow to microvasculature.
Each RBC is packed with what, and what will it do?
Hemoglobin carries o2
How much hemoglobin is contained in 100 ml of blood?
15 grams
Each RBC contains how much hemoglobin?
250 million
How much o2 can each rbc carry?
about 1 billion.
How many liters of o2 are found in the entire blood?
1 liter.
Total RBC numbers is a function of what?
Oxygen Content.
What is erythropoiesis?
Making of RBC in Bone marrow.
What controls the amount of RBC made?
A hormone called Erythropoietin aka epo
Where is erythropoietin primarily produced at?
Kidneys.
When will erythropoietin be made?
When blood oxygen is low the oxygen in the kidneys will be low and this signals the kidneys to make more erythropoitin.
Erythropoietin is an example of what type of feedback to maintain homeostasis?
Negative feedback.
What is physiologic polycythemia?
An increase in RBC in people who live in high altitudes.
What is hemoglobin made of?
It is a protein made of amino acids and Iron.
What is needed to make erythropoietin?
Vitamin b12 and folic acid.
How long will RBC last in the blood?
120 days.
Without centrifuging blood just letting the RBC seperate out from the plasma and the WBC what would this process be called?
Erythrocyte sedimentation rate.
What is a normal erythrocyte sedimentation rate?
5 mm/hour
What would an increased erythrocyte sedimentation rate mean?
It is elevated during infection, cases of arthritis and inflammatory diseases.
Why will the erythrocyte sedimentation rate increase during infections?
Tissues release acute phase reactant proteins that stick on RBC and allow them to clump together and this increases the rate of sedimentation.
What besides water is the major component of Plasma?
Plasma Proteins.
What plasma protein helps with pressure of capillaries? And how? What is this called?
Albumins. The fluid will want to come inside the capillaries to establish an equillibruim with the albumins. Called Plasma colloidal osmotic pressure.
Plasma proteins are involved in what?
Carriers, defense, clotting/coagulation.
Name the 3 broad groups of Plasma proteins? List them in the order of smalles to largest.
Albumins, Glogulins, and Fibrinogens.
Nearly all the plasma proteins are made where?
In the liver.
What Plasma proteins help as a carrier function? what will they specifically bind?
Albumins. Fatty acids. Globulin
What are the 3 types of globulin?
alpha= a globulin Beta = b globulin gama = y globulin
List the 3 groups of plasma proteins starting with the least commn and ending with the most common.
Fibrinogen, Globulins, Albumins
Alpha a globulin does what?
Transports or carries: proteins, lipids (HDL), Steroid-binding proteins, and clotting factors.
Beta B globulin does what?
Transports or carries: Lipids (LDL), and Iron.
Beta B globulin carries iron as what?
Transferrin.
Gama Y globulin does what?
it is a family of various antibodies.
What is fibrinogens main purpose?
Precursor to a clot.
clotting is a function of what?
plasma proteins.
Fibrinogen is a precursor to what?
Fibrin.
What is fibrin?
A molecule that can polymerize to form an insoluble mesh used to minimize blood loss.
Fibrin does what to blood?
Coagulates it (turns from liquid to solid) aka clotting.
What happens to Fibrinogen to make a clott?
Fibrinogen ———> Fibrin Monomer——–> Cross-linking fibrin Ca2+ Fibrin stabalizing and Thrombin Factor
What does hemostasis mean?
Blood same. This is the ability to maintain blood volume.
What 3 mechanisms help with hemostasis?
- Vascular constriction. 2. Platelet 3. Clot formation.
What induces vasoconstriction?
Trauma to a vessels wall. This trauma releases a local vasoconstrictive factor from smaller vessels like endothelin-1.
How do platelets stimulate vasoconstriction?
They release thromboxane A2 and serotnin.
What will promote platelet aggregation to help make a platelet plug?
Thromboxane and thrombin.
While forming a platelet plug thrombin functions through what system?
IP3/DG
Platelets are small fragments from where?
Bone marrow megakaryocytes.
What do Platelets have inside of them?
NO nucleus, but they have various organelles. They are also covered with lots of receptors.
What are the three processes a platelet goes throught when contacting a damaged vessel wall?
- Adherence 2. Aggregation 3. Secretion.
What makes a platelet adhere to a damaged vessel wall?
Contact with damaged endothelia and contact with tissue proteins including collagen.
Simultaneous aggregation of platelets form what?
A Platelet plug
What are platelet plugs used for that clots are not?
Platelet plugs are useful in routine daily injuries that produce tiny holes in vessels.
Aspirin can effect platelets how?
It can inhibit platelet aggregation.
During normal hemostasis which pathway is used?
Both intrinsic and extrinsic pathways.
What are the major players in blood clotting besides factors?
Thrombin is the major player, but ca2+ and platelet phospholipids are also important.
What is calcium chelation?
A way to keep blood from clotting in a test-tube because it removes calcium and this stalls many clotting reactions.
What is the primary activation for the intrinsic pathway in blood clotting?
contact with collagen or trauma to the blood.
What is the primary activation for the extrinsic pathway of blood clotting?
Release of tissue factors.
How long will blood clotting take?
1-6 minutes.
What makes the blood clotting system turn from positive feedback to negative feedback?
Anti-clotting mechanisms.
What specifically happens to Fibrinogen to make it fibrin?
Clipping off parts of Fibrinogen.
What is needed to change fibrinogen to fibrin?
ca2+ and thrombin.
What is needed to make thrombin?
You start with prothrombin and you need ca2+ and prothrombin activator. Then you get thrombin.
Prothrombin activator is a complex substance made of several molecules, but mostly what?
Factor X.
What has to happen to factor X for it to help make Prothrombin?
factor X —————> Factor Xa (a signals that it is the activated form) ca2+
What ways can prothrombin be activated?
Intrinsic pathway and Extrinsic pathway.
