BIPN 100 Final Exam

What determines resistance? (3)

length, radius, viscosity

Decreasing rate of contraction

m2Achr receptors are Gi protein which reduces Ca and increases K+ - causes hyperpolarization

ANP - atrial natiuretic peptide affecting blood pressure

o BP high, atria release ANP as atria stretches out more Decreases reabsorption at nephron Decreased ADH Leads to vasodilation

RAAS (renin angiotensin aldosterone system) affecting blood pressure

o Lowered BP in kidney - Releases renin in blood - Renin increases angiotensin II in blood - A ll = vasocontriction, release of aldosterone

Na+ Reabsorption in Kidney

o Na+ reabsorption: In the proximal tubule, the tubule lumen has Na the passively goes into the proximal tubule cell ATP pumps Na+ into the interstitial fluid

Dromotropic Definition

pertaining to the rate of the conductive fibers (A/V node conduction speed) and subsequently the rate of electrical impulses of the heart - agents that are dromotropic are usually inotropic and chronotropic

P-R segments

the depolarization is delayed at the AV node, there is no change in voltage difference and thus, a flat line - atrial depolarization and AV node conduction time

QT interval

time for ventricles to depolarize and repolarize

T wave

ventricular repolarization

Glucose Reabsorption in Kidneys

Glucose is transported into the proximal tubule cell with secondary transport (tags with Na+) Glucose and Na+ is reabsorbed K+ leak channel for the Na/K+ ATP ase active transport

4 Phases of the Cardiac Action Potential

- 0: action potential, opens Na+ channels - 1: Na+ channels deactivate, Kto channels open - 2. L type Ca2+ channels open, plateau because K+ = Ca - 3: Ca2+ closes, K+ dr opens - 4: K+ "leak" channels open

Nodal Cardiac Cells

- AV and SA node - Smaller diameter fibres and fewer gap junctions to delay the signal and wait for the atria to pump all blood onto the ventricle in AV

How to change the force of contraction in cardiac cell

- Activating B1 adrenergic receptor (sympathetic) o Increases in cAMP o More Ca2+ entering externally o More Ca2+ from SR o Increased myosin ATPase rate o Increased uptake of Ca2+ back in the SR no parasympathetic pathway can change force of contraction

Predict how changes in the Starling forces (hydrostatic pressures and colloid oncotic pressures) and the filtration coefficient will affect capillary exchange.

- Capillary colloid osmotic pressure in (πc) -Interstitial fluid hydrostatic pressure (Pi) -Interstitial fluid colloid osmotic pressure (πi) -Starling's Equation: o Out - In o filtration = k [(Pc + πi) - (Pi + πc)]

Decreased efferent + decreased afferent arteries affecting GFR

- Decreased afferent: decreased GFR because lower capillary blood pressure (Ph) - Decreased efferent: increased GFR, increased capillary blood pressure

EDV

- End Diastolic Volume - Preload

ESV

- End Systolic Volume - amount of blood in ventricles after contraction

H+ excretion in kidney

- In proximal tubule bringing in HCO3 and secreting H+ alleviates acidosis 1. NHE (Na+/H+ exchange) secretes H+ 2. H+ in filtrate combines with filtered HCO3- to form CO2 and H2O using carbonic anhydrase 3. CO2 diffuses into cell 4. CO2 combines with water to form H+ and HCO3 using carbonic anhydrase again 5. H+ is secreted again 6. HCO3 is reabsorbed with Na+

Explain how water reabsorption is regulated by ADH (vasopressin) in the nephron.

with maximal vasopressin, the collecting duct is freely permeable to water and water leaves by osmosis and carried away by the vasa recta capillaries. Urine is concentrated. - activation of ADH receptors leads to a cAMP cascade that results in increased aquaporin channels on cells of collecting duct. - activation by decreased blood pressure and increased osmolarity

Explain how activation of macula densa cells can lead to constriction in the afferent arteriole.

- Macula Densa are specialized cells lining the thick ascending limb that are sensitive to sodium chloride 1. Directly, using paracrine factors a. When NaCl levels are high, they signal smooth muscle constriction immediately adjacent to them of afferent arterioles via ATP signaling, which lowers GFR 2. Indirectly, using renin-angiotensin-aldosterone pathway a. When filtrate NaCl levels are low, they signal smooth muscle constriction of efferent arterioles, via renin - angiotensin - aldosterone pathway that involves juxtaglomerular (granular) cells which increase GFR

Predict how ouabain might affect reabsorption of glucose, Na + and H2O.

- Ouabain inhibits Na+ K+ ATPase - o Glucose reabsorption would decrease because Na+ build up inside the cell

Positive Inotropy on PV loops

- PV Loop will have increased slope of total tension curve - less blood in the the ventricles which will shift PV loop to the left - positive inotropy means increased contraction

SV

- Stroke Volume - SV = EDV - ESV

Chemoreceptors and regulation of BP - what happens when detects lower O2, pH or increased CO2

- activates CN 9 and 10 - leads to increased sympathetic and decreased sympathetic

Mean Arterial Pressure (MAP) - definition - how vasoconstriction affects

- average pressure in the aorta \MAP = CO x TPR (TPR is total peripheral resistance, opposition to blood flow) - VC increases venous return (blood returning to the heart)

Draw the SA Node, atrial muscle, AV node, ventricular muscle action potential

- beginning of the P wave coincides with phase 0 of the atrial action potential and - beginning of the QRS complex coincides with phase 0 of the ventrivular action potential

CO

- cardiac output is the amount og blood pumped by a ventricle in a given period of time - CO = HR x SV

Regulation of BP: baroreceptors - what happens when there is a decrease in pressure at the art

- decrease pressure at the carotid (vessels to brain) and aorta activates the CN 9 and 10 and leads to decreased parasympathetic and with increased sympathetic

Two ways to increase inotropy - diastolic blood pressure - pulse pressure

- diastolic blood pressure, increased TPR cuased by constriction of arterioles via alpha 1, sympathetic - increase pulse pressure by increased force contraction by beta 1

PV Loop - how to generate PV Loops - Where does mitral/aortic valve open? EDV/ESV?

- from the active force and resting force - ESV is when the aortic valve closes, EDV is when mitral close

Secreting organic anions

- need to build up negative amino acids to bring in OA via cotransporter

Frank Starling Effect

- stroke volume of the heart increases in response to an increase in the volume of blood filling the heart (EDV) - blood stretches ventricular wall, causing cardiac muscle to contract more forcefully, lengthens sarcomeres and able to expel incresed EDV

P wave

- the SA node creates a voltage difference, at the max peak, both atria contract - atrial depolarization

Excitation-Contraction in Cardiac Steps ( 5)

1. AP is initiated by pacemaker cells and travels via gap junctions 2. AP travels down T tubules and activate L type Ca channels 3. Calcium induced calcium release: Increase in Ca2+ ions activate Ryr on SR 4. Bind to troponin 5. Just like skeletal muscles

Pacemaker Action Potential

1. Hyperpolarization causes If channels to open and depolarize 2. T type Ca channels open right before threshold 3. L type Ca channels open at the threshold 4. K+ channels open at peak, Ca2+ closes 5. Repeat

Compare and contrast excitation-contraction coupling in cardiac vs skeletal (2)

1. Ryr is induced by Ca2+ influx and not by DHP or voltage change 2. AP is initiated by pacemaker cells

Changing rate of contraction (2)

1. depolarize/hyperpolarize cell from threshold 2. change the rate of rise of depolarization

Increasing rate of contraction

1. with B1 receptors, more PKA means more net influx of Na+ and Ca2+ 2. Epinephrine and Norepinephrine 3. leads to reduced repolarization and more rapid depolarization

Prepotential defintion

AKA pacemaker potential; the slow positive increase in voltage in the membrane potential that happens after the end of an AP and before new one

Cardiac and Skeletal Refractory Periods Difference and Why

Cardiac refractory periods are much longer than skeletal to prevent tetanus (using 100%, reduce fatigue)

Counter Current with NaK ATPase

NaK ATPase increases osmolarity of the interstitual fluid and the vasa recta collects the water drawn our via osmosis and traps the Na+ within the kidney via counter current.

Inotropic Defintion

Pertaining to force of contraction - receptors form an ion channel pore (?) - can only increase force of contraction

Chronotropic Definition

Pertaining to the rate of contraction - can be positive or negative

Poiseuille's equation and flow equation

Q = delta P / R - P is pressure - Q is flow - R is resistance

QRS Complex

Ventricle depolarization, the voltage difference is so large because there are a lot of contractile cells in the ventricles

•Explain how the lymphatic system returns fluid to the circulatory system.

When blood passed from the arteries to the arteriole and into capillaries, some of the plasma usually leaks into lymphatic vessels, along with: lymphocytes and phagocytes and other cells of the immune system. This then drain into the lymph nodes where pathogens are attacked and killed and further immunological reaction is initiated. This usually results in a swollen lymph node. The lymphatic fluid then rejoins the circulatory system by draining into a vena cava

Myogenic Definition and Pacemaker Cells

cells depolarize spontaneously, all cardiac are myogenic but pacemaker cells are the fastest

ST interval

constant because this is when the blood from ventricles go to arteries. Repolarization begins here