SOURCE – RAMYA RAGHU TEXTBOOK
BEVELS
BLEACHING AGENTS
SOURCE – RAMYA RAGHU TEXTBOOK
ETIOLOGY OF TOOTH DISCOLORATION
SOURCE – RAMYA RAGHU TEXTBOOK
MANAGMENT OF PAIN (IN CONSERVATIVE)
SOURCE – RAMYA RAGHU TEXTBOOK
CONSERVATIVE INSTRUMENTS MOTIONS
SOURCE – RAMYA RAGHU TEXTBOOK
Glycolysis
- 1 glucose (6-carbon sugar) breaks down to 2 pyruvates (3-carbon sugar).
- Net 2 ATP produced: 2 consumed (investment phase) and 4 generated (pay off)
- 2 NADH produced
REGULATED STEPS
Hexokinase
- Glucose + ATP Glucose-6-phosphate + ADP
Phosphofructokinase
- Fructose-6-phosphate + ATP → fructose-1,6-biphosphate + ADP
Pyruvate kinase
- Phosphoenol pyruvate + ADP → Pyruvate + ATP
ENZYMES OF GLYCOLYSIS
Listed in chronological order (substrate/product in parentheses)
- Hexokinase (glucose/glucose-6P)
- Phosphoglucose isomerase (glucose-6P/fructose-6P)
- Phosphofructokinase (fructose-6P/fructose-1,6P)
- Aldolase (fructose-1,6P/G3P & DHAP)
- Triose phosphate isomerase (DHAP/G3P)
- Glyceraldehyde-3-phosphate dehydrogenase (G3P/1,3-bisphosphoglycerate)
- Phosphoglycerate kinase (1,3-bisphosphoglycerate /3-phosphoglycerate)
- Phosphoglycerate mutase (3-phosphoglycerate /2-phosphoglycerate)
- Enolase (2-phosphoglycerate /phosphoenol pyruvate)
- Pyruvate kinase (phosphoenol pyruvate /pyruvate)
Glucose Metabolism Overview Part II
GLUCOSE OXIDATION EQUATION
Glucose + 6 O2 –> 6 CO2 + 6 H2O + Energy (ATP + heat)
- Most energy is generated in mitochondrial matrix
Common Abbreviations:
- ATP: adenosine triphosphate
- NADH: nicotinamide adenine dinucleotide
- FADH2: flavin adenine dinucleotide
- CoA: Coenzyme A
KEY PROCESSES IN GLUCOSE OXIDATION
- Glycolysis
- Pyruvate decarboxylation
- Citric acid cycle (also known as the Krebs’ cycle and the tri-carboxylic acid (TCA) cycle)
- Oxidative phosphorylation (electron transport chain & chemiosmosis)
CITRIC ACID CYCLE
- 1 glucose molecule requires 2 citric acid cycle turns
- Input for each turn: 1 Acetyl CoA
- Output for each turn: 3 NADH + 2 CO2 + 1 ATP + 1 FADH2
- NADH & FADH2: electron transfer molecules for oxidative phosphorylation
- Occurs in mitochondrial matrix
Substrate level phosphorylation
- ATP generated from substrates in glycolysis and citric acid cycle
- NOT from oxidative phosphorylation via NADH or FADH2
OXIDATIVE PHOSPHORYLATION
- Input: 10 NADH + 2 FADH2 (from glycolysis, pyruvate decarboxylation & CAC)
- Generates 30-34 molecules of ATP per glucose
- Main energy-generating process in respiration
- Comprises electron transport chain and chemiosmosis
- Occurs on inner mitochondrial membrane
Electron transport chain
- Series of redox reactions
- Pumps proton from matrix into intermembrane space
- Generates electrochemical gradient for ATP synthesis via ATP synthase
- Contains several protein complexes (I through IV)
- NADH gives electrons to complex I
- FADH2 gives electrons to complex II
- Complex I, III, and IV pump H+ into intermembrane space (Complex II DOES NOT)
- Complex IV consumes 1 O2 (final e- acceptor) to produce 2 H2O
Chemiosmosis
- ATP synthase: harnesses energy in electrochemical gradient (generated by ETC) to synthesize ATP from ADP & Pi
Glucose Metabolism Overview Part I
GLUCOSE OXIDATION EQUATION
Glucose + 6 O2 –> 6 CO2 + 6 H2O + Energy (ATP + heat)
- Most energy is generated in mitochondrial matrix
Common Abbreviations:
- ATP: adenosine triphosphate
- NADH: nicotinamide adenine dinucleotide
- FADH2: flavin adenine dinucleotide
- CoA: Coenzyme A
KEY PROCESSES IN GLUCOSE OXIDATION
- Glycolysis
- Pyruvate decarboxylation
- Citric acid cycle (also known as the Krebs’ cycle and the tri-carboxylic acid (TCA) cycle)
- Oxidative phosphorylation (electron transport chain & chemiosmosis)
GLYCOLYSIS
- 1 glucose –> 2 pyruvate + 2 ATP + 2 NADH
- Anaerobic reaction: no O2 required
- Occurs in cytosol
Substrate level phosphorylation
- ATP generated from substrates in glycolysis and citric acid cycle
- NOT from oxidative phosphorylation via NADH or FADH2
PYRUVATE DECARBOXYLATION
- Pyruvate + CoA + NAD+ –> Acetyl-CoA + CO2 + NADH
- Occurs in mitochondrial matrix
Glucose Metabolism: Energy Yield
GLYCOLYSIS
- Occurs in the cytosol
- Anaerobic
- Inputs: 1 Glucose
- Outputs: 2 Pyruvates, 2 ATP, 2 NADH
PYRUVATE DECARBOXYLATION
- Occurs in the matrix
- Aerobic
- Input: 2 Pyruvates
- Outputs: 2 Acetyl CoA, 2 CO2, 2NADH
CITRIC ACID CYCLE
Kreb’s Cycle of Tricarboxylic Acid Cycle
- Occurs in the mitochondrial matrix
- Aerobic
- Input: 2 Acetyl CoA
- Output: 4CO2, 2ATP, 6NADH, 2FADH2
OXIDATIVE PHOSPHORYLATION
- Electron transport
- Chemiosmosis
- Aerobic
- Inputs: 10 NADH, 2FADH2
- Outputs: 30-34 ATP
Total ATP Output: 30-38 ATP
- Intertextual variation exists: exact calculations beyond the scope of this tutorial.
- Approximates yield for both eukaryotes & prokaryotes.
Esophagus & Stomach Histology
ESOPHAGUS
Long, muscular tube delivers food from the pharynx to the stomach.
- Mucosa layer
- Comprises stratified squamous epithelium; layers of flattened cells provide protection against physical and chemical damage from the foods, liquids, and salivary juices traveling to the stomach.
- Muscularis mucosae is also visible in our sample.
- Submucosal layer
- Submucosal glands
- Glands of the submucosal and mucosal layers produce protective and lubricating mucous, which contributes to the protective barrier.
- Submucosa and mucosa form longitudinal folds in the relaxed esophagus; these folds expand to accommodate foods and liquids during swallowing.
- Muscularis externa layer
The composition of the muscularis externa layer changes along its length, as follows:- The upper 1/3rd comprises skeletal muscle fibers in both the circular and longitudinal layers;
- The middle 1/3rd comprises a circular layer of skeletal muscle and a longitudinal layer of smooth muscle;
- Both layers of the lower 1/3rd, which opens to the stomach, contains smooth muscle fibers.
- The outermost layer of the esophagus is adventitia; once the esophagus passes through the diaphragm, and is no longer anchored to the body wall, it becomes serosa.
STOMACH
Connects with the esophagus, superiorly and the duodenum, inferiorly.
Regions of the stomach:
- Cardiac, where the esophagus and stomach meet
- Fundus, in the upper left corner
- Body, which is the largest region of the stomach
- Pyloris, which opens to the duodenum
Gastric Folds, aka, rugae - Line the empty stomach; expand to accommodate foods and liquids during gastric filling
Histological Details: - Surface mucous epithelium
- These cells secrete mucous and form a physical and chemical barrier to protect the underlying stomach wall from stomach contents. In addition to ingested foods and liquids, the stomach wall is potentially vulnerable to the gastric juices it releases as part of digestion.
- Pits
- Invaginations of the surface mucosal epithelium form pits, which open to glands deeper within the mucosa; depending on their location in the stomach, the glands produce mucous and/or gastric juices.
- Lamina propria is visible in our sample between the pits and glands.
- Slips of muscularis mucosae can be seen extending into the gastric fold.
Glands:
- Cardiac and pyloric glands are primarily mucous-secreting; in other words, they do not produce significant quantities of gastric juices.
- Cardiac glands are highly coiled at their ends, or bases.
- Pyloric glands are highly branched.
- Gastric glands of the fundus and body produce both mucous and gastric juices; they are responsible for chemical digestion.
- Surface epithelial cells line the pit, and secrete surface mucous.
- Mucous neck cells also secrete mucous.
- Parietal cells, which appear as round, bulging, and light pink in the histological sample, are found within the neck and base of the gastric gland. These cells, which are also referred to as oxynitic cells, secrete hydrochloric acid and intrinsic factor (required for vitamin B12 absorption).
- Stem cells are also found within the neck; these cells play important roles in the constant renewal of gastric mucosal cells.
- Chief cells reside in the base of the gland, and stain darker due to secretory granules containing pepsinogen, which is a precursor to pepsin for protein digestion.
- Enteroendocrine cells, which is an umbrella term for a variety of cells that secrete peptide hormones. For example, G cells secrete gastrin, and D cells secrete somatostatin.
- The cells of the gastric gland lie on a basement membrane, which separates them from the surrounding glands and lamina propria.
