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195 Cards in this Set
- Front
- Back
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What does ATP stand for?
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Adenosine triphosphate
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What is ATP?
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A nucleotide with high energy phosphate bonds.
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How can you oxydize something?
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-By adding oxygen
-By taking H away Example: NAD+ and NADH + H+ |
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What is 1kcal in Joules?
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4180 J (about 4000 J)
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What is 1kJ in calories?
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239 cal (about 250 cal)
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How much of the released energy is captured in ATP?
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About 40%
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How much heat do you get per mol ATP?
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About 10kcal
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Describe glycolysis.
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Anaerobic - happens when energy n the cell is dropping
Glucose to pyruvate 2 ATP per glucose Does not require oxygen, so not really burning, more like fermentation After the regulatory steps, the rest happens easily, when ATP to ADP ratio is low |
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Describe the Kreb's cycle
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Aerobic (indirectly)
Generates CO2, reduced substrates (NADH +H), and 2ATP per glucose Cycle itself doesn't need oxygen but further downstream needs it |
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Describe oxidative phosphorylation
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Aerobic (directly)
Generates H2O (and heat) 34 ATP per glucose |
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Where does glycolysis occur?
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Cytoplasm
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What does glycolysis yield per glucose?
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2 pyruvate, 2 ATP, and 2 NADH
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Where does the Kreb's Cycle occur?
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Mitochondrial matrix
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What regulates the Kreb's Cycle?
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NADH and ADP
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What does the Kreb's Cycle yield?
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4 NADH + H+, 1 FADH and 1 ATP per pyruvate
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Draw the top of the Kreb's Cycle...
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Pyruvate, arrows to CO2 and Acetyl CoA on lift, NAD and NADH +H on right
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In oxidative phosphorylation, how many stations are there for each NADH?
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3 stations
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Where does oxidative phosphorylation occur?
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The mitochondrial inner membrane
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What regulates oxidative phosphorylation?
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O2
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What does oxidative phosphorylation generate?
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H20 and oxidized substrates
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What does oxidative phosphorylation yield?
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3 ATP per NADH, 2 per FADH2
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Where in the body is glycogen very dense?
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The liver
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What are limiting factors of metabolism?
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Oxygen, fuel, mitochondrial volume
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How many times does a human heart typically beat?
How many times does a heart beat in most mammals? What's the difference? |
2.5 billion times in human
500 to 600 million times in most mammals We have incredible longevity |
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How much blood does the heart pump?
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5.5 L
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What is flow?
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Change in pressure/ resistance
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What does the heart develop from?
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Angiogenic cells in splanchnic mesoderm
(in coelomic cavity) |
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Where are the heart and lungs located?
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Lungs located in pleural cavity of thorax
Heart located in the cardiac cavity between lungs |
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What do the right and left ventricles do?
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Right ventricle supplies pulmonary circulation (from heart to lungs and back) - project anteriorly, smaller
Left ventricle supplies systemic circulation (from heart to rest of body and back), posterior, larger |
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How much of the total blood flow supplies the heart?
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About 4 to 5 %
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Be able to draw the path of blood flow in heart
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Include directions
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When do AV valves open?
When do they close? What are the AV valves? |
Open when P(atrial)>P(ventricle)
Close when P(atrial)<P(ventricle) Left is bicuspid(mitral), right AV is tricuspid |
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When do aortic and pulmonary valves open and close?
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Open when:
P(Left ventricle)>P(aorta) P(RV)>P(Pulmon. art.) and close when pressure fall below |
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What do AV valves have to prevent collapse & backflow (prolapse) during ventricular contraction?
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Papillary muscles, connected by tendons
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What is a mitral valve prolapse?
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The mitral valve allows blood to leak back into the left atrium, causing a heart murmur
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How does fetal circulation work?
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Lungs are collapsed, oxygenated blood comes from placenta
The types of fetal circulation are systemic and umbilical |
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Trace the flow of fetal circulation.
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1. Oxygenated blood coms from umbilical vein to inferior vena cava (50% goes through liver)
2. Mixes w/ deoxygenated blood in right atrium 3. Resistance from collapsed lungs ('X') prevents blood from traveling through pulmonary artery |
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What does the forman ovale do in fetal circulation?
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Opening with a valve that shunts blood from Right to Left atrium
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What does the ductus anteriosus do?
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Opening with that shunts blood from pulmonary artery to aorta (this blood is more mixed)
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What happens to the foramen ovale and the ductus arteriosis after birth?
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The Foramen ovale normally closes immediately because of pressure increase (if not potential birth defect)
Ductus arteriosis closes in 1-2 days |
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What is blue baby syndrome?
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Patent ductus arteriosis leads to high pulmonary pressure, lung damage, cardiac hypertrophy
Blue baby -- it fails to fuse to baby is getting a lot of deoxygenated blood |
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Where is cardiac muscle located?
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Encircles chambers to squeeze them (like a fist)
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What are gap junctions?
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Gaps between intercalcated discs cause depolarization to travel between cardiac muscle cells.
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What is the natural pacemaker?
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Sinoatrial node (autorhytmic cells at top of right atrium)
Raises and lowers heart beat based on body's needs |
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What is the atrioventricular node?
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Controls heart rate based on depolarization of myocardial cells
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How much of heart muscle fibers are non-contractile?
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About 1%
They form a conducting system to transmit the depolarization to myocardial cells in the two ventricles |
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What in the Bundle of His?
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The pathway between ventricles
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What are Purkinje's Fibers?
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Conduct impulse rapidly throughout the ventricles
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When do ventricles contract?
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After atria (forcefully and simultaneously)
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What are some aortic and carotid bodies? What do they do?
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Chemoreceptors sense CO2
Baroreceptors sense blood pressure Relay sensory info to hypothalamus and brain stem (negative feed back) Motor output to control heart rate via autonomic NS: - parasympathetic (vagus nerves) and sympathetic |
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Describe the PQRST wave.
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P wave... atria contract
Q down R wave... ventricles contract (depolarize?) S down T wave... repolarize |
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What are the 2 ventricular phases?
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Diastole ("filling phase" at low pressure)
[ventricles relaxed - atria contract] blood enter from R&L atria into R&L ventricles Systole ("emptying phase" at high pressure) [ventricles contract - atria relax] - blood eject from right ventricle into pulmonary artery left ventricle into aorta and systemic circulation atria fill |
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When does isovolumetric ventricular contraction occur?
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During systole
Valves remain closed Open during ventricular contraction |
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How is heart work measured?
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Work is measured by how much blood volume is squeezed by the pressure generated = P*V
Area under the curve of left ventricular pressure |
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What is cardiac output?
How much is it different between rest and exercise? |
Heart rate x stroke volume
(ml/min) = (beats/min) x (vol/beat) 40% increase in cardiac utput Cardiac output x change in blood 02) 12X difference rest vs. exercise |
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How is cardiac output regulated?
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1. Increase heart rate (sympathetic stimulation - increases membrane permeability)
2. Increase stroke volume (more volume, sympathetic stimulation [norepinephrine], less arterial pressure) Starling's Law: cardiac output adjusts to venous return |
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What is atherosclerosis?
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Build up of fatty materials (plaques, white blood cells, other material) inside arteries
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What causes atherosclerosis?
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Oxidation of Low Density Lipoproteins (LDLs) = transport molecules
Irritate artery wall, stimulate white blood cells (macrophages), which form plaque, cause arterial wall expansion, etc |
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What are complications of atherosclerosis?
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1. Stenosis (narrowing of artery): blood pressure
2. Ruptured artery = aneurysm 3. Rupture of plaque: thrombus (clot), ischemia (restricted blood supply), infarction (tissue death) |
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What are the functions of blood?
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Gas exchange
Metabolism (metabolites, ions, fuels) Waste elimination (renal filtration) Hormone transport Body defense: immune system Fluid and ion balance Heat transfer (storage and dissipation): temperature regulation |
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What are erythrocytes?
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red blood cell
Biconcave (no nucleus) Lack of mitochondria Incapable of aerobic resp Can't do cellular repair Components Hemoglobin Lipids, ATP, carbonic anhydrase Function: transport oxygen from lungs to tissues and carbon dioxide from tissues to lungs (red blood cells) |
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What is erythropoietin?
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Increases red blood cell production
(when used as a blood doping agent, caused death among elite cyclists because the blood was so viscous) |
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How does blood flow redistribute with exercise?
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Flows to skeletal muscle and away from abdominal organs, other
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What are platelets?
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Used to clot blood
If platelet count falls, <50,000 per ml bleeding becomes a problem Very small cells (no nucleus) that can release a variety of substances in response to local tissue damage |
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What happens with blood clotting?
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Circulating platelets trapped and plug leak
Fibrinogen is a rod shaped soluble protein which gets converted through catalyst thrombin to an insoluble protein fibrin Make a net of fibers immobilizing the fluid portion of blood |
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Describe ABO blood groups.
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Type A (has A antigens, anti-B antibodies)
Type B (has B antigens, anti-A antibodies) Type AB (has A and B antigens, no antibodies) universal recipient Type O (has no antigens, anti- A and anti-B antibodies) universal donor |
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How is hemoglobin structured?
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4 Heme (Fe) groups (bound to O2) + globin
Hb4O2 |
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What kind of binding does Hb do?
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Cooperative reversible binding
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Does a fetus have increased or decreased O2 affinity?
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Increased (facilitates O2 dissaciation from maternal Hb, enabling O2 to diffuse across placenta & bind to Fetal Hb)
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What is the Bohr effect?
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Right shift in O2 dissociation curve, reduced pH and elevated CO2 decrease Hb binding affinity
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Hb O2 binding affinity
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Ask someone who knows
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What are factors that cause a right shift in the O2 dissociation curve/decreased Hb binding affinity?
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Altitude
Temperature |
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What is myoglobin?
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Myoglobin binds O2 as it diffuses into the muscle cell, keeping the concentration gradient for diffusion elevated
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What is the swim bladder?
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An internal gas filled organ that contributes to buoyancy
Gas gland secretes lactic acid and CO2, which causes oxygen to drop out of hemoglobin, and diffuse into swim bladder Goes to the rete mirabile ("wonderful net") - group of arteries and veins through which the gas produced by gas gland goes back to swim bladder Countercurrent exchange -- O2 and lactic acid |
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What is sickle cell anemia?
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Single aa mutation in b subunit gene, selected for resistance to malaria
Sickled RBCs clump and aggregate, blocking small vessels Also die more quickly, leading to severe anemia |
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Describe the path of adult circulation.
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Systemic veins -> Vena cavae -> right atrium -> right ventricle -> pulmonary trunk and arteries -> pulmonary capillaries -> pulmonary veins -> left atrium -> left ventricle -> aorta -> systemic arteries
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What causes pipe flow in the circulatory system?
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Difference in pressure
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What is the Poiseuille equation?
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Flow (ml/min) Q = [pi (delta P)r^4]/ [ 8 (viscosity)(length) ]
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What is the equation for resistance in pipe flow?
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R = delta Pressure/ Flow(Q)
R = (8 viscosity x length)/ pi r^4 |
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What are the benefits and risks of vascular resistance?
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Vascular resistance provide an effective mechanism to control blood flow
But too high a resistance can cause high blood pressure |
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What is manifold design?
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Branching architecture of circulatory system (akin to airways in lungs)
Reduces flow reistance and flow velocity in small diamete vessels (capillaries) where diffusion occurs Slow-moving blood allows more time for exchange between capillary blood and tissues |
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How are capillaries designed?
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Walls are single endothelial cells in thickness
Primary point of exchange between the blood and the interstitial fluid Intercellular clefts assist the exchange |
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What is hyperemia?
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Increased flow in response to increased metabolism of local tissues
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What is vasodilation?
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Widening in blood vessels due to smooth muscle relatxation
Flow goes up |
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How is blood pressure dampened?
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By arterial wall elasticity (arteries are very elastic)
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How does blood drain?
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From smaller veins close to the surface to larger, deeper veins.
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How do arteries respond to and regulate flow?
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Change their diameter to regulate their vascular resistance and blood flow to three signals:
Extrinsic 1) Sympathetic nervous system (vasoconstriction) 2) Hormones (epineprhine and norepinephrine) Intrinsic 3) Local chemical factors often enhance blood flow (affect smaller arterioles that regulate flow to local capullary beds in the tissues) -> vasodilation |
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Describe the fish cardiovascular system.
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Blood enters the gills directly after leaving the heart. The gills have a large capillary bed.... pressure drops across gills
single circuit (versus humans double circuit with systemic and pulmonary systems) |
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How is the lungfish CV system different from other fish?
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Lungfish also can breathe air...
Valves close off so that blood is redirected to lung |
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What are the processes of the oxygen transport?
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Ventilation -> Diffusion -> Convection -> Diffusion
Check about where specifically these are supposed to occur |
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What is diffusion like?
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Fick's equation -
Concentration difference/ barrier thickness = concentration gradient Effective over short distances Design: maximize surface area (A) for exchange minimize diffusion path maximize concentration difference; hence concentration gradient |
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What are alveoli?
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Tiny sac-like endings that inflate and deflate during breathing to exchange gases with blood flowing through capillaries in alveolar wall...
Maximize surface area means increased diffusion |
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What layers does gas have to pass through for diffusion?
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Pass through two cell layers: epithelial and capillary
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What does the branching architecture of airways and pulmonary circulation provide?
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Hierarchical subdivision into millions of small alveoli
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Compare air and water as a respiratory media.
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Water is far more dense and viscous, and has less O2 content.
The respiratory effort relative difference: 1: 23,000 |
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What is Patmos at sea level?
What is PO2 at sea level? What is alveolar PO2 accounting for dead space? |
Patmos is 760 mmHg
PO2 is 160 mmHg Alveolar PO2 at sea level is 100 mmHg |
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What dissolves most easily - CO2, N2 or O2?
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CO2
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What are responses to high altitude?
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1) Increased ventilation (volume)
2) Chemoreceptors become more sensitive 3) Decreased PO2 stimulates peripheral receptors to increase ventilatory rate 4)Kidneys release EPO so there are more RBCs |
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Describe inspiration.
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Increase thoracic volume
1) Expansion of thorax (via external intecostal muscles elevating and expanding ribs) 2. Depression of diaphragm creates negative pleural pressure to draw air into lungs |
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Describe exhalation
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Passive when breathing at rest
1. elastic recoil of stretched ligaments & connective tissue of thorax and diaphragm (reduces respiratoy work) 2. Active during exercise: abdominal muscles assist internal intercostals creates positive pleural pressure to force air out of lungs |
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What is pulmonary surfactant?
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Lipoprotein compex that wets the surface of alveoli, reducing their surface tension. This makes it easier to inflate alveoli at low lung volumes (small alveolar size) - increases lung compliance
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What kind of flow exchange does tidal respiration use?
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Concurrent flow exchange
(countercurrent in fish gill respiration and bird lungs) |
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Compare mammal and bird lungs.
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Bird lungs are rigid, use cross current flow past para bronchi and our separate hole.
Mammal lungs have thin-walled alveoli and pulmonary capillaries, with tidal, discontinuous flow |
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How do fish gills work?
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Secondary lamellae provide large SA and short diffusion path (L)...
countercurrent flow of water versus blood flow via @second lamellae allows >90% of O2 extraction! (vesus <50% w/tidal ventilation of mammals) |
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What are problems with smoking?
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Particulate accumulation in lungs
compliant, flabby lung, doesn't recoil to a large extent, have to actively in inflate lungs - 20% of metabolism |
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What are advantages of respiratory drug delivery?
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Advantage over oral medications: avoid digestive breakdown prior to gut absorption & more rapid)
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What is asthma?
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Bronchiole constriction due to smooth muscle contraction associated with inflammation
2x reduction in radius, results in 16x reduction in flow |
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What regulates respiration?
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CO2!
(O2 responds to it) breathing is both involuntary and voluntary chemoreceptors and baroreceptors also make a difference |
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Why do doctors monitor head circumference of children?
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The brain case grow around the brain. By about age 6, the brain is basically done growing.
The face, on the other hand, has two cycles of growth. |
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What is microcephaly?
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Why the brain doesn't grow property.
HIV causes it because it leads to death of neural tissue. |
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What are some principle regularities of growth?
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Different "parts" have somewhat different trajectories
High correlation part-to-part High correlation age-to-age |
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When is it ok to cross centrile lines during growth?
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During adolescence
Otherwise, it's a cause for concern |
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What are major hormones that control growth and where are they produced?
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Growth hormone - anterior pituitary- stimulates muscle growth of bone and muscle
Thryonine hormones - thyroid-general metabolic rate Insulin-like Growth Factor-1 - liver (also bones) - mediates GH action in growth plates Cortisol - adrenal cortex - catabolic action, opposes insulin Insulin - pancreas - glucose uptake and utilization Estrogen - gonads - stimulate and terminate bone growth, potentiate insulin fat Androgen - testes, also some in adrenal cortex (potentiate insulin in muscle) |
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What does the thyroid need to make crucial hormones? What happens if it doesn't have it?
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iodine
goiters |
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What is essential for all anabolic processes?
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Insulin
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What opposes insulin?
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Cortisol
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What does growth hormone deficiency cause? Growth hormone excess?
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Dwarfism
Acromegaly |
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What are reasons for having bones?
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1) Resistance to deformation
2) Oppose gravity 3) Permit muscles to generate movement 4) Protect organs (eg brain, thorax) 5) Be strong 6) Store calcium 7) Make blood cells 8) Allow joint movement |
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What is stiffness?
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Stress/strain
Strain is deformation, stress is force |
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What makes blood cells?
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Haematopoetic cells in bone marrow
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What are the two types of bone?
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Compact (cortical)
vs. Trabecular (spongy, cancellous) |
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What is bone made of?
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Organic: Collagen
Mineral: Calcium phosphate Also some H20 and Non-collagenous proteins |
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Describe collagen.
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Offers flexibility, resistance to tension, toughness
Triple helix of polypeptides Fibrils bundles into rope-like fibers to resist tension, provide sites for mineralization |
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Describe calcium phosphate.
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Stiffness and resistance to compression
Hydroxyapatite Crystallites are packed in between fibrils |
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Why are fibers arranged like plywood?
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Fibriles going in different directions with different textures gives strength in multiple planes
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How are circumferential lamellae laid out? Trabecular? Osteonal?
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1) Layers around surface of bone
2) Layers in small struts 3) Tube-like layers around a vascular channel |
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Why are your bones filled with more and more osteons?
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Old bone replaced pretty much only by osteons.
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What is cartilage?
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Poorly organized complex of hydrophilic proteoglycan complexes, collagen, H20
(lots of binding sites) Highly negative electrochemical charges hold apart GAG complexes under load |
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What are ligaments?
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bone to bone connections
Collagen bundles with limited elasticity prevent hyperextension |
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What are tendons?
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Muscle bone connections
Collagen and elastin |
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What kind of cells are depository?
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Bone (osteoblasts)
Cartilage (chondrocytes) Tendon (fibroblasts) Ligament (fibroblasts) Resorptive cells Chondroclasts Osteoclasts |
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What is mesenchyme?
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Embryonic connective tissue stem cells made up of loosely associated, often stellate cells, and a dispersed extracellular matrix
Mesodermal sclerotome From the neural crest |
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What is the process through which osteoblasts synthesize bone?
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1. Lay down collagen matrix
2. Mineralize it |
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How does intramembranous bone formation work?
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Periosteal membrane
Osteoblasts Collagen matrix (osteoid) Biomineralization mostly form around organs/spaces, like head, clavicle Bone is added in sutures. Bone moved through drift. |
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How does endochondral bone growth work?
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Perichondrial membrane -> chondrocytes -> anlagen (means preform) -> replacement of cartilage w/both
Note: cartilage does NOT turn into bone growth plates displaces, pushes |
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How are bones repaired?
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1. Osteoclasts remove old bone.
2. Osteoblasts lay down new bone around a blood vessel 3. Result = osteon that replaces old bone (Haversian system) |
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What is osteoporosis?
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When bone resorption > bone deposition
affects mostly trabecular bone |
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What is estrogen's role in osteoporosis?
Why are women more at risk? |
When Ca++ levels are low, parathyroid gland produces PTH which stimulates bone resorption by osteoclasts
Estrogen inhibits PTH activation of osteoclasts Women stop growing earlier, so have lower peak bone, and estrogen levels lower following menopause. |
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What are some types of glial (supporting) cells in the brain?
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Astrocytes - regulate neurotransmitters at synapses & other aspects of neuron's environment (including energy)
oligodendrocytes - coat CNS neurons in myelin (Schwann cells coat PNS neurons) Ependymal cells - secrete cerebrosinal fluid (CSF) Microglia - immune cells |
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How do we divide the brain up in terms of evolution?
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Neocortex (cerebrum)
Paleocortex (olfactory and limbic systems) Non-cortical brain and cerebellum |
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How do we divide up the brain in terms of development?
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1. Prosencephalon
telenchephalon (cerebrum) diencephalon (eyes, pituitary, hypothalamus, epiphysis) 2. Mesencephalon 3. Rhombencephalon Metencephalon (pons, cerebellum) Myelencephalon (medulla) |
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How do we divide up the brain in terms of anatomy?
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1. Forebrain
(cerebrum, thalamus, hypothalamus) 2. Midbrain 3. Hindbrain (pons, medulla, cerebrum) |
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What is the prosencephalon?
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The forebrain
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What is the mesencephalon?
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Midbrain
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What is the rombencephalon?
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Hindbrain
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What is the telencephalon?
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The cerebrum
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What is the myelencephalon?
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Brain stem
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What is the relatively larger part of the brain compared to other animals in human?
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Forebrain
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What does brain mass scale as?
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.75 (negatively allometric, fits Kleiber curve)
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What is the encephalization quotient?
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Observed brain mass/estimated brain mass
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What are characteristics of fish brains?
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Big brain stem
Small forebrain Big cerebellum |
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What are some parts of the hindbrain?
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Pons, medulla, cerebellum
(Remember that it is an ancient part of the brain) |
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Describe the medulla oblongata.
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Highway of axons to/from brain
Nuclei (cell bodies) that control autonomic functions (breathing, heart rate, blood pressure, swallowing, coughing/sneezing |
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Describe the pons.
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On the top of brain stem
Connects cerebral hemispheres with contralateral hemispheres of cerebellum Wakefulness and alertness Damage can lead to sleeplessness or hyperalertness |
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Describe the cerebellum.
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As many neurons as rest of brain.
Monitors sensory input from body and coordinates with outgoing motor commands from cerebrum Gross motor function (posture/balance, muscle tone, coordiantion) Damage leads to closs of control on contralateral side |
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Describe the midbrain.
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Small in mammals
(Connects brainstem to forebrain) Has nuclei that coordnate/integrate body movements with forebrain (damange --> Parkinson's) eye movements (sup colliculus) pain (periaqueductal gray region, PAG) reward, addiction, movement (substantia nigra) motor coordination (red nucleus) |
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What is the diencephalon?
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"Twin brain"
Cluster of ancient regulatory regions atop the brainstem |
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What is the thalamus?
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Relays all sensory information to cerebrum (except smell)
Also involved in awareness and learning) |
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What is the hypothalamus?
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Controls release of hormones by pituitary gland
Homeostatsis of thirst, heart rate, blood pressure Interacts with limbic system to help control emotions |
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What controls circadian rhythms?
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Epithalamus
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What is the part of the brain that actively thinks?
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The cerebrum
(receives/processes sensory information, complex cognitive processes like language, thinking, awareness, memory, consciousness) |
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What is the outer cortex made of?
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Grey matter
Deeply folded with gyri and sulci |
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What are the lobes in the cerebral cortex?
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Frontal lobes (motor functions)
Parietal lobes (integrate stimuli) Temporal lobes (sensory input from ears) Occipital lobe (sensory input from eyes) |
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What is the corpus callosum?
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Thick bundle of myelinated axons that links two hemispheres
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What does the basal ganglia do?
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Conscious motor control
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What is the limbic system?
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Corticol/subcortical structures around brainstem
generation/regulating emotions, learning |
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What does an fMRI scan show?
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Relative blood flow in the brain, so where O2 consumption is the highest.
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Describe the autonomic nervous system.
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Sympathetic (thoraco-lumbar)
Parasympathetic (cranio-sacral) |
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What are sensory pathways for skin, eyes, ears, and nose?
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Skin: somatosensory cortex in parietal lobe
Eyes: visual cortex in occipital lobe Ears: auditory cortex in temporal lobe Nose: olfactory cortex in frontal lobe |
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What are characteristics of the sensory pathway?
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1. Synapse in thalamus
2. Usually pass to opposite side of brain 3. Form representational "maps" |
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What structures are associated with the limbic system?
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Thalamus (sensory information)
Hippocampus (memory, navigation) Amygdala (rewards, fear, mating urges) Hypothalamus (heart rate, blood pressure, etc) Also related to olfactory bulbs, pituitary and other deep structures And to prefrontal cortex |
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What effect does exercise have on hypothalamus?
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It elevates brain derived neurotrophic factors (BDNF) in hypothalamus, which promote memory
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How much energy does the brain need?
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20-25% resting metabolism
300-420 kCal/day For Na and K pumps, neurotransmitter synthesis and transport, and Brain-blood barrier |
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Describe the brain-blood barrier
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Brain and blood separated by Cerebrospinal Fluid (CSF), which bathes entire CNS and is synthesized in choroid plexus
Permits passage of plasma, glucose, gasses, hormones, and ketone bodies, but most things need to be pumped |
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What is the Circle of Willis?
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The cerebral arterial circle
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What are the three dural membranes in the CNS?
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Outer: dura mater
Inner: pia mater Middle: arachnoid mater (subarachnoid space filled with CSF) |
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What causes hydrocephalus?
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Excess CSF (too much production and/or blocked drainage)
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How do we cool ourselves?
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Sweating, especially on face and scalp... leads to countercurrent cooling
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What are problems with having such a big brain?
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1. Big brains take more time to grow
2. Hard to give birth to 3. Brains are costly (need a lot of calories) |
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When energy is immediately needed, what sources are used before aerobic metabolism?
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1. Energy already in cells (only last a few seconds)
2. Creatine protein (stored in muscle - phosphate switches back and forth between creatine and ATO) 3. Anaerobic glycolysis - not very efficient This process lasts 2 to 5 minutes. |
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What is oxygen debt?
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The body needs to make up for the work it did without oxygen before aerobic metabolism sets in because of lactate accumulation. Oxygen makes lactate able to turn into glucose
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From what structures is energy drawn when you first start exercising?
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First, glycogen from striated muscle
Then, liver glycogen If working hard, then adipose tissue |
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How much oxygen can hemoglobin carry? What about myoglobin?
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Hemo: 4
Myo: 1 |
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What affects the work of sherpas and sprinters?
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Myoglobin stored in muscles allows quick bursts of work
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What does VO2 represent?
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How fast oxygen is taken up by the body
(ml/kg/min) |
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What is the principle variable determining oxygen uptake during exercise?
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Heart rate
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What are factors for VO2 capacity?
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Genetics, increased training
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What is CRP?
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C-reactive protein
non-specific immune system protein, elevated by a broad range of immune system challenged. Elevated CRP s Tsimane children is associated with slower growth in the succeeding three months (hunter gatherer society) |
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What are some essential, reducible, and expendable processes?
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Essential: cell maintenance, circulation, neural activity
Reducible processes: thermoregulation, locomotion, growth Expendable processes: reproduction, fat storage |
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What are the roles of insulin?
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Takes up glucose, makes glycogen
Liberate free fatty acids Store fat Make glycogen (building up storage) Protein anabolism Fatty acid synthesis |
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What are catabolic hormones?
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Glucogen
Epinephrine (adrenal medulla) Cortisol (releases stored fat) |
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What are anabolic hormones?
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Insulin
Growth hormone IGF Sex steroids |
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Where is most energy stored?
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Fat (135000 kCal)
Protein (24000 kCal) Carbohydrate (840 kCal) |
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What are strategies and mechanisms of starvation physiology?
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Reduce activity
Reduce BMR Reduce glucose utilization (lower insulin) Restrict anabolism (lower GH, sex steroids) Increase fat utilization (increase cortisol) Prioritize brain metabolism (shift to ketone bodies) |
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What are ketone bodies?
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byproducts when fatty acids are broken down for energy in liver and kidney
used for energy in heart and brain main ones are acetone, acetoacetate, and beta-hydroxybuturate |
