MasterPass PHYSIOLOGY 3

NADH is used to transport electrons from the cytoplasm to the mitochondria.

Insulin secretion is reduced and glucagon is secreted.

It increases from approximately 250 ml/min at rest to over 4000 ml/min during strenuous exercise.

It produces water (H2O) by combining O2 with 2H+ and generates ATP.

Mobilisation of triacylglycerols in fat and gluconeogenesis by the liver.

Ventricular isovolumetric contraction.

It shifts to the right due to reduced local pH and increased temperature in exercising muscle.

The physiological response involves cardiovascular, neurohumoral, and renal compensatory mechanisms.

Two ATPs.

4 ATP

Glucose

It causes chronotropic (heart rate) and inotropic (force of systolic contraction) effects.

Arterial and cardiac baroreceptors, vasomotor centre in the nucleus tractus solitarius, parasympathetic and sympathetic discharge.

The synthesis of glucose from pyruvate, lactate, glycerol, alanine, and glutamine.

Carbohydrate, stored as glycogen and liberated into glucose.

The synthesis of glycogen to store glucose.

36 ATP

It increases dramatically from a basal rate of approximately 5 l/min to over 20 l/min.

2 ATP

Concentrations of acetyl-CoA and citrate rise, which reduces glycolysis.

In the mouth with mastication.

Glucose.

Passive ventricular filling.

During ventricular ejection (Phase 3).

At the end of ventricular ejection, beginning of ventricular isovolumetric relaxation (Phase 4).

Cardio-respiratory and metabolic systems.

Afferent impulses from proprioceptors in muscle.

Carbon, hydrogen, and oxygen.

It enters the Krebs Cycle to produce energy.

Muscle uptake of glucose reduces and muscle shifts to using fatty acids as fuel.

Neurohumoral, renal, metabolic, race, and genetic factors.

Use of N2O, use of opiates, use of etomidate, use of neostigmine, hypotension.

Middle ear surgery, ophthalmic surgery (especially squint-correction surgery), gynaecology surgery.

The breakdown of triglycerides into glycerol and fatty acids.

The vestibular system, peripheral pain pathways, intestinal chemoreceptors, and the cerebral cortex provide direct afferent input to the vomiting centre via cranial nerves VIII, IX, and X.

Coronary blood flow and arterial oxygen content (CaO2).

Because gluconeogenesis depletes the supply of oxaloacetate, which is essential for acetyl-CoA to enter the Krebs cycle, leading to ketogenesis.

NADH and CO2

It increases due to a rise in heart rate and augmentation of stroke volume.

MAP = Cardiac Output (CO) × Systemic Vascular Resistance (SVR)

It increases due to the accumulation of metabolites such as adenosine and potassium.

Ventricular ejection.

Ventricular isovolumetric relaxation.

To split the 6-carbon sugar glucose into two molecules of the 3-carbon sugar pyruvate.

Glycolysis generates four ATPs while two are used up, making a net gain of two ATPs.

Pain, fear, sight, smell, memory, anticipation.

Cephalic phase, stomach distension, proteins in the stomach, and increased pH of chyme in the stomach.

Because it is too slow to be of great importance during high-intensity exercise such as sprinting.

Increased ADH secretion from the posterior pituitary leads to water conservation, and increased adrenal release of noradrenaline, adrenaline, and cortisol via sympathetic nervous system activation.

CoPP is the difference between aortic pressure and intraventricular pressure. It is calculated as CoPP = aortic pressure - intraventricular pressure.

Spinal nerves.

Stimulation of the sympathetic nervous system due to pain, fear, and anxiety.

Vitamins A, D, E, and K.

It reduces the need for glucose, thereby diminishing muscle breakdown.

The maximum amount of oxygen a subject can utilize at a cellular level to produce ATP to power exercise, measured in ml/kg/min.

Pyruvate molecules.

To enable heat loss.

Glycolysis, the Krebs cycle, and oxidative phosphorylation and the electron transport chain.

The generation of ATP from glucose molecules.

To provide glucose when the supply of dietary glucose runs out.

The generation of glucose from substrates such as pyruvate.

Pyruvate enters an anaerobic pathway and is converted into lactate (lactic acid).

It detects toxins and opioids, triggering the vomiting response.

The process where lactate produced during anaerobic respiration is converted back to glucose in the liver.

Into right and left hemi-liver plus caudate lobe.

The cephalic phase of gastric regulation is activated, involving the cerebral cortex, hypothalamus, medulla oblongata, and vagus nerve, leading to increased gastric juices and gastrin in the blood.

30%

Lactate begins to accumulate in the blood.

Potential complications of vomiting include aspiration (particularly if GCS is reduced), wound dehiscence, electrolyte imbalance (loss of hydrogen, potassium, and chloride), dehydration, and elevated intraocular and intracranial pressure.

Atherosclerotic vessels are stenosed and have reduced blood flow.

They are accepted by oxygen molecules, which combine with H+ ions to form water.

Glycogen phosphorylase.

The metabolic exchange of gases in the body’s tissues, dependent on the predominant fuel used for cellular metabolism.

Upper oesophageal, lower oesophageal, pyloric, ileocaecal, sphincter of Oddi, and anus.

It is under conscious control and constricts to avoid air being drawn into the stomach during breathing.

It inhibits further gastric secretions.

Because of renal and gastrointestinal losses; however, it will be reduced in chronic liver disease.

Phase 1: atrial contraction, Phase 2: ventricular isovolumetric contraction, Phase 3: ventricular ejection, Phase 4: ventricular isovolumetric relaxation, Phase 5: passive ventricular filling.

Female gender, non-smoker, previous PONV, history of motion sickness.

The breakdown of glucose to produce pyruvate and energy.

Phosphofructokinase.

Obesity may affect blood pressure through a possible link to insulin resistance.

It is one of the factors that can affect long-term blood pressure.

The two phases of vomiting are the pre-ejection phase and the ejection phase.

Acetoacetate and β-hydroxybutyrate.

Increases insulin release, inhibits secretion of gastric juices, and slows gastric emptying.

Hexagonal.

Also known as the atrial reflex, it is a rapid increase in heart rate due to increased venous return to the heart, aiming to restore atrial and vena caval pressures to normal.

To use NADH and FADH2 generated in the Krebs cycle to make ATP.

Amino acids and fatty acids in the small intestine.

The ratio of CO2 production to O2 consumption (RER = VCO2/VO2).

135,000 kcal.

Hepatocytes produce bile, which is excreted into the hepatic ducts of the portal triad via the bile canaliculi.

The acinus.

Elevated conjugated bilirubin, alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT).

To preserve protein and muscle mass.

Blood flow through the hepatic artery is autoregulated to maintain constant flow despite changes in mean arterial pressure down to approximately 60 mmHg. Below this, flow is pressure dependent.

The great cardiac vein and the middle cardiac vein.

Krebs Cycle

Amino acids that can be converted into glucose through gluconeogenesis.

Pyruvate is no longer converted into acetyl-CoA and is exported to the liver for conversion into glucose.

Fatty acids.

They start using ketones and free fatty acids (FFA) as fuel.

Nausea is the sensation of the need to vomit. Vomiting is the involuntary, forceful expulsion of gastric contents via the mouth.

Lactate produced by muscles is converted back into glucose in the liver.

The breakdown of glycogen to release glucose.

129 molecules of ATP.

1800–2000 g.

The hepatic artery, portal vein, and bile duct.

Acetyl coenzyme A (acetyl CoA).

Glycerol is fed into the Krebs cycle as dihydroxyacetone phosphate.

The juxtaglomerular apparatus releases renin, which converts angiotensinogen to angiotensin I. ACE converts this into angiotensin II, causing vasoconstriction and stimulating aldosterone release, which increases sodium and water re-absorption at the distal convoluted tubules, expanding plasma volume.

They are close to the portal triad, surrounded by blood rich in oxygen and nutrients, and contain mitochondria-rich cells suited to oxidative metabolism and glycogen synthesis.

Ketones become the major fuel source for the brain, providing more than 70% of its energy requirements.

The breakdown of glycogen to release glucose.

24,000 kcal.

By restoring venous return with fluids and administering sympathomimetics, particularly ephedrine.

The entry of chyme into the duodenum.

By the union of the splenic vein and superior mesenteric vein.

Prevents reflux of acidic stomach contents into the oesophagus and opens ahead of peristalsis during swallowing to allow food and fluid to enter the stomach.

Approximately 60%.

The left atrium, left ventricle, and most of the interventricular septum.

30 ATP

Atrial contraction.

In plants, they form structures (e.g., cellulose), and in animals, they are stored as glycogen.

The formation of glycogen from glucose.

It alters the balance between parasympathetic and sympathetic discharge, thereby altering heart rate, stroke volume, and systemic vascular resistance.

Cranial nerves V, VII, IX, X, XII.

The metabolic substrate switches to fatty acids.

6 ATPs.

There is a redistribution of cardiac output from the skin, muscle, and viscera to the brain and heart.

Cholesterol and triglycerides.

Cranial nerve X.

Blood becomes progressively poorer in oxygen and nutrients from zone 1 to zone 3.

Twice.

High amounts of glucose and ATP.

1600 kcal.

Regional anesthesia (spinal, epidural, and interscalene blocks), hemorrhage/hypovolemia, and inferior vena cava compression in supine pregnant patients.

Gastrin begins to exert a negative feedback to inhibit further acid secretion.

CaO2 = [Hb × SaO2 × 1.34] + [PaO2 × 0.023].

Heart rate, contractility, afterload, tissue mass, and temperature.

A diamond-shaped area of the liver supplied by a terminal branch of the portal vein and of the hepatic artery and drained by a terminal branch of the bile duct.

By increasing its coronary blood flow.

The right atrium, right ventricle, sinoatrial node, and in 90% of people, the atrioventricular node.

When pressure within a small artery or arteriole increases, the smooth muscle constricts to reduce blood flow, and vice versa.

Simple sugars (glucose and fructose) and complex sugars (starch and cellulose).

The process of producing glucose from non-carbohydrate sources.

Sodium intake, atrial natriuretic peptide, bradykinin, nitric oxide, glucocorticoids, renal function, psychological stress, obesity, atherosclerosis, renin-angiotensin-aldosterone system.

The production of ketone bodies from fatty acids and ketogenic amino acids.

Sodium intake can affect long-term blood pressure.

Mainly in the liver, and to a small extent, in the kidneys.

The chemoreceptor trigger zone (CTZ) provides efferent input to the vomiting centre, which is located in the medulla.

The liver acinus is divided into zones 1–3.

The Krebs cycle (also called the citric acid cycle or the tricarboxylic acid cycle).

Fatty acids in the small intestine.

The lobule.

Cephalic phase, gastric phase, and intestinal phase.

The liver produces bile, which is used for the emulsification of dietary lipids to allow their absorption.

In ml/kg/min of O2.

In the center of the lobule, surrounded by hepatocytes.

Zone 3.

As blood viscosity increases, flow decreases. Haematocrit is a major determinant of blood viscosity.

The liver can hold as much as 15% of the circulating blood volume and can act as a large blood reservoir.

Kupffer cells remove old erythrocytes, bacteria, and other antigens via phagocytosis.

It is a branch of the coeliac artery.

Prothrombin time (PT) indirectly determines the amount of available clotting factors and is used to assess synthetic function.

The right coronary artery (RCA) and the left coronary artery (LCA).

Phase 2 reactions (Glucuronidation/Acetylation/Sulphonation/Methylation) involve conjugation of phase 1 products to increase water solubility, allowing renal or biliary excretion of the compound.

It leads to vasodilatation.

The CTZ lies in the floor of the fourth ventricle in the area postrema and is functionally outside of the blood-brain barrier. It contains dopamine (D2) and serotonin (5-HT3) receptors.

Reduced baroreceptor input leads to reduced afferent discharge in glossopharyngeal and vagus nerves, inhibiting the cardio-inhibitory centre and activating the vasomotor centre, resulting in increased sympathetic activity, increased force of cardiac contraction, tachycardia, and increased SVR.

The pressure changes in the left ventricle drive the opening and closing of the heart valves, ensuring unidirectional blood flow through the heart.

The hepatic production of large amounts of ketone bodies (acetoacetate and 3-hydroxybutyrate) from acetyl-CoA.

During their metabolism, intermediary products like pyruvate, acetyl CoA, and oxaloacetate are formed and fed into the Krebs cycle to yield ATP.

They favor interstitial fluid movement into the circulation through a fall in intravascular hydrostatic pressure and a rise in oncotic pressure.

During systole, the CoPP of the left ventricle can equal zero or less, preventing coronary blood flow.

The brain and the heart.

Thought, sight, and smell of food.

Stretch and chemoreceptors are activated, leading to increased gastric secretions, increased peristalsis, and increased tone of the lower oesophageal sphincter.

Vitamins A, D, E, K, copper, and iron (as ferritin).

Reduction in energy expenditure, glycogen stores are used within 24 hours, and alternative fuels such as ketones are used to minimize protein wasting.

Fatty acids, ketones, and glycerol provide all of the energy requirements for the body, except for the brain and red blood cells, which still require a glucose source.

It inhibits further gastric secretions and motility.

The difference between lower oesophageal sphincter (LOS) pressure and intragastric pressure. The closer the barrier pressure is to zero, the more likely reflux will occur.

The metabolic pathway that yields glucose from non-carbohydrate sources such as pyruvate, lactate, glycerol, and amino acids.

Via the coronary sinus.

The intrinsic ability of an organ to maintain a constant blood flow despite varying perfusion pressure.

Between 60 and 180 mmHg.

Factors include the proportion of unbound drug in the plasma, rate of drug presentation to the liver, rate of enzymatic breakdown, and hepatic function.

Atrial natriuretic peptide causes vasodilatation, while vasopressin and angiotensin II cause vasoconstriction.

S1 is associated with the closure of the atrioventricular valves at the beginning of ventricular systole, and S2 is associated with the closure of the aortic and pulmonary valves at the beginning of ventricular diastole.

The breakdown of glycogen to liberate glucose.

Cranial nerve VIII.

In extreme conditions such as ultra marathon running or starvation.

During the pre-ejection phase, nausea occurs, sympathetic stimulation causes tachycardia, tachypnoea, and sweating, and parasympathetic stimulation causes salivation, relaxation of the upper and lower oesophageal sphincters, and giant retrograde contraction of the small intestine.

1 ATP, 3 NADH, and 1 FADH2.

The process of storing glucose as glycogen, primarily in the liver and muscles.

Carbohydrate, protein, and fat.

Activation of left ventricular chemo- and baroreceptors results in unopposed parasympathetic tone, leading to bradycardia, vasodilation, and hypotension, known as vasovagal syncope.

The wider the diameter, the greater the blood flow.

34 ATP.

Adrenaline stimulates glycolysis, glucagon stimulates glycolysis and inhibits glycogenesis, and insulin inhibits glycolysis and stimulates glycogenesis.

The VCO2 curve rises steeply, and the RER exceeds 1.0 due to additional non-metabolic CO2 production.

10 ml O2/min/100 g at rest and 70 ml O2/min/100 g during heavy exercise.

Because acetyl-CoA cannot be converted into pyruvate.

Fatty acids and ketones.

As the mean arterial pressure rises, the hepatic artery constricts to maintain a constant blood flow and vice versa.

The liver maintains blood glucose concentrations via glycogenesis, gluconeogenesis, and glycogenolysis.

Increases secretion of gastric juices, increases motility, encourages growth of mucosa, constricts lower oesophageal sphincter (LOS), and relaxes pyloric and ileocaecal sphincters.

The portal triad.

Vitamin D.

Acidic chyme in the small intestine.

Hepatic artery, portal vein, and bile duct.

They are at the periphery of the acinus, receive blood that has already undergone exchange of gases and metabolites, and are rich in smooth endoplasmic reticulum and cytochrome P450, making this the key region for drug and toxin biotransformation.

Approximately 100 g.

The size of the triacylglycerol stores.

A structure, usually made up of circular muscle, that surrounds the opening of a hollow organ or body and constricts to close it.

Alanine and aspartate aminotransferases (ALT and AST) are released into the blood following hepatocellular damage. ALT is more liver-specific than AST.

Approximately 70%, providing around 40% of the liver’s oxygen requirements.

Less than 50%, but it can increase in response to increased oxygen demand.

The right coronary artery (RCA).

Volatiles and noradrenaline reduce hepatic blood flow.

It causes vasoconstriction.

The anaerobic threshold (AT), which occurs due to inadequate oxygen delivery.

During the ejection phase, respiration temporarily ceases mid-inspiration, the hyoid and larynx raise to open the crico-oesophageal sphincter, the glottis closes, the soft palate elevates to close off the nasopharynx, contraction of the diaphragm and abdominal muscles results in a rise in intra-abdominal pressure, the gastro-oesophageal sphincter opens, and gastric contents are ejected.

As heart rate increases, diastolic time and therefore coronary perfusion time, especially to the left ventricle, is reduced.

Stimulates contraction of the gallbladder to release bile, stimulates release of pancreatic enzymes, and augments the effect of CCK.

Between 45% and 65% of VO2 max.

They traverse the lobule, draining blood from the peripheral portal triads to the central vein.

100 ml/kg/min (approximately 1800 ml/min).

Approximately 70% from the portal vein and 30% from the hepatic artery.

Gastric inhibitory peptide (GIP), secretin, and cholecystokinin (CCK).

To provide sufficient glucose to the brain and red blood cells.

It inhibits stomach emptying.

The left anterior descending (LAD) artery and the left circumflex (LCx) artery.

Symptoms include jaundice, encephalopathy, coagulopathy, ascites, raised intracranial pressure, hypoglycaemia, renal dysfunction, loss of vascular tone, and immunosuppression.

The liver synthesizes, transaminates, or deaminates proteins and converts ammonia into the less toxic urea.

Stimulates contraction of the gallbladder to release bile, stimulates release of pancreatic enzymes, induces feeling of satiety, inhibits gastric emptying, and enhances actions of secretin.

Kupffer cells.

1600–2000 kcal per 24 hours.

Approximately 24 hours, less if exercising.

Approximately 70%.

Relaxes to allow chyme to pass out of the stomach into the duodenum.

30%.

Stimulation of the sympathetic nervous system results in hepatic arterial vasoconstriction.

The heart, kidney, and brain.

It becomes pressure dependent.

Nitric oxide (NO), endothelium-derived relaxing factor (EDRF), prostacyclin (PGI2), endothelin, and thromboxane A2.

Blood flow through the portal vein is passive and dependent upon splanchnic blood flow.

Vessels that drain directly into the heart chambers and contribute towards true shunt.

Both general and spinal anaesthesia reduce hepatic blood flow.

Local tissue hypoxia and increased metabolic waste products such as H+, K+, adenosine, and CO2.

The liver synthesizes albumin, immunoglobulins, clotting factors (all except factor VIII), haptoglobin, C-reactive protein, and anti-thrombin III.

As hepatic portal venous flow changes, the hepatic artery vasoconstricts or vasodilates reciprocally to maintain overall constant hepatic blood flow.

The liver plays a key role in the biotransformation of drugs, chemicals, and toxins via the cytochrome P450 electron transport chain.

Phase 1 reactions (Hydrolysis/Oxidation/Reduction) provide a reactive group for subsequent phase 2 reactions and generally reduce the activity of a drug but may sometimes produce a toxic or active intermediate.