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Medullary osmotic gradient: countercurrent multiplier, urea recycling & vasa recta countercurrent exchange

By: HWC, Views: 8444

▪ The primary cause of the medullary osmotic gradient is the active transport of solutes. • In the ascending limb of the loop, active transport of Na+ ions drives passive reabsorption of Cl- ions. • Addition of these ions to the interstitial fluid of the medulla increases its osmolarity...

Factors that increase metabolic rate and heat production

By: HWC, Views: 7777

• All vital biochemical reactions are temperature dependent. • The overall rate at which metabolic reactions use energy is known as the metabolic rate. • Metabolic rate greatly determines body temperatures. • Temperature is maintained by balancing the loss of heat to the environment...

Enzyme-Catalyzed Reactions

By: HWC, Views: 7201

S P Substrate in great excess ([S] -- [E]) (More correctly [S] -- KM, but more on this later) Zero order rate equation: v = k where k is the zero-order rate constant (with respect to substrate). (More correctly [S] -- KM, but more on this later) Substrate forms complex with enzyme. ...

Effect of blood chemistry - stimuli, hyperventilation response and hypoventilation response

By: HWC, Views: 7453

• Respiratory rate is effected by changes in: • Blood pH. • Blood Pco2. • Blood P02. • Chemoreceptors in the central and peripheral nervous systems closely monitor the Fr, CO2 and 02 levels in blood. • Changes in frequency of impulses from Chemoreceptors affect respiratory r...

Depolarization of the SA node, Action potentials of the myocardium & ANS effects

By: HWC, Views: 7633

• A typical contractile cell in the myocardium has a resting membrane potential. • The resting membrane potential of cells in the SA node is not fixed, and is known as the pacemaker potential. • The action potential of a healthy SA nodal cell has three parts: • Pacemaker potential: ...

Michaelis–Menten equation & Kinetic parameters

By: HWC, Views: 7507

The Michaelis–Menten equation is the rate equation for a one-substrate enzyme-catalyzed reaction. This equation relates the initial reaction rate (v0), the maximum reaction rate (Vmax), and the initial substrate concentration [S] through the Michaelis constant KM—a measure of the substrat...

Exercise and cardiac output

By: HWC, Views: 7475

• Cardiac output: • Maintains blood flow throughout the body. • Measure of blood volume ejected from the heart over a given time. • Determined by multiplying heart rate by stroke volume (CO = SV x HR). • Heart rate: Number of beats/min. • Stroke volume: Amount of blood eject...

Chemical Equilibrium between N2O4 (colorless gas) and NO2 (brown gas)

By: HWC, Views: 6983

For a system at equilibrium: ◆ both forward and reverse reactions are occurring simultaneously ◆ rate of forward reaction must equal rate of reverse reaction OR Rate forward = Rate reverse ◆ concentrations of reactants and products remain constant with time the equilibrium positio...

Control of ventilation rate by other brain centers (posts, hypothalamus & cerebral cortex)

By: HWC, Views: 7680

Forced ventilation: • The inspiratory area stimulates accessory inspiratory muscles. • Inspiration is more forceful. • Inspiratory area activates expiratory area, which sends impulses to the expiratory muscles (internal intercostals and abdominal muscles). • Expiration muscles c...