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Questions and Answers
What is the primary function of the digestive system?
What is the primary function of the digestive system?
Which process begins the digestion of food?
Which process begins the digestion of food?
What is the role of bile in the digestive process?
What is the role of bile in the digestive process?
Which of the following accurately describes peristalsis?
Which of the following accurately describes peristalsis?
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Which digestive juice is primarily responsible for breaking down proteins?
Which digestive juice is primarily responsible for breaking down proteins?
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What enzyme is responsible for carbohydrate digestion in the mouth?
What enzyme is responsible for carbohydrate digestion in the mouth?
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Which substance is absorbed into the blood through secondary active transport?
Which substance is absorbed into the blood through secondary active transport?
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Which of the following is a catabolic process for glucose?
Which of the following is a catabolic process for glucose?
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What is the primary function of the urinary system?
What is the primary function of the urinary system?
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What is the process by which urine is formed that involves filtering blood?
What is the process by which urine is formed that involves filtering blood?
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Which nutrient is metabolically processed through deamination?
Which nutrient is metabolically processed through deamination?
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Which of the following substances is NOT considered a metabolic waste product disposed of by the kidneys?
Which of the following substances is NOT considered a metabolic waste product disposed of by the kidneys?
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Which nutrient is absorbed into the lymphatic system by simple diffusion?
Which nutrient is absorbed into the lymphatic system by simple diffusion?
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What is the approximate blood pH that must be maintained for acid-base balance?
What is the approximate blood pH that must be maintained for acid-base balance?
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Where are the kidneys located in relation to the diaphragm?
Where are the kidneys located in relation to the diaphragm?
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What is the typical storage capacity of a healthy adult bladder?
What is the typical storage capacity of a healthy adult bladder?
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Which part of the nephron is responsible for filtration?
Which part of the nephron is responsible for filtration?
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What is the primary function of the ureters?
What is the primary function of the ureters?
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What structure comprises the renal corpuscle in a nephron?
What structure comprises the renal corpuscle in a nephron?
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How much filtrate does the kidneys produce per minute as part of the Glomerular Filtration Rate (GFR)?
How much filtrate does the kidneys produce per minute as part of the Glomerular Filtration Rate (GFR)?
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What occurs during the reabsorption stage of urine formation?
What occurs during the reabsorption stage of urine formation?
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What is the Glomerular filtration rate (GFR) in liters per day?
What is the Glomerular filtration rate (GFR) in liters per day?
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How much of the filtrate produced daily is reabsorbed by the kidneys?
How much of the filtrate produced daily is reabsorbed by the kidneys?
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What is the Glomerular capillary hydrostatic pressure (GHP)?
What is the Glomerular capillary hydrostatic pressure (GHP)?
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Which of the following substances is primarily involved in the obligatory reabsorption in the PCT?
Which of the following substances is primarily involved in the obligatory reabsorption in the PCT?
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What is the effect of blood osmotic (colloidal) pressure on filtration?
What is the effect of blood osmotic (colloidal) pressure on filtration?
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What happens if blood glucose levels rise above 180 mg/dl?
What happens if blood glucose levels rise above 180 mg/dl?
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What movement primarily occurs in the descending loop of Henle?
What movement primarily occurs in the descending loop of Henle?
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How does sodium reabsorption affect chloride movement in the PCT?
How does sodium reabsorption affect chloride movement in the PCT?
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What role does the loop of Henle play in the kidney function?
What role does the loop of Henle play in the kidney function?
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Which statement is true regarding the ascending loop of Henle?
Which statement is true regarding the ascending loop of Henle?
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What triggers the release of ADH (anti-diuretic hormone)?
What triggers the release of ADH (anti-diuretic hormone)?
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What effect does ADH have on urine concentration?
What effect does ADH have on urine concentration?
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What is the function of the distal convoluted tubule (DCT) and collecting tubule (CT)?
What is the function of the distal convoluted tubule (DCT) and collecting tubule (CT)?
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What is a symptom of a lack of ADH?
What is a symptom of a lack of ADH?
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How does the nephron adaptation serve desert animals?
How does the nephron adaptation serve desert animals?
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What does secretion in the kidneys involve?
What does secretion in the kidneys involve?
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What is the primary function of the kidneys in urine formation?
What is the primary function of the kidneys in urine formation?
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What does ADH (antidiuretic hormone) do in relation to urine production?
What does ADH (antidiuretic hormone) do in relation to urine production?
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What is considered oligourea in terms of daily urine production?
What is considered oligourea in terms of daily urine production?
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Which of the following substances increases the rate of salt and water loss from the kidneys?
Which of the following substances increases the rate of salt and water loss from the kidneys?
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What is the main process by which dialysis removes waste from the blood?
What is the main process by which dialysis removes waste from the blood?
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How does alcohol affect urine production?
How does alcohol affect urine production?
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What is a common treatment option for kidney failure?
What is a common treatment option for kidney failure?
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What happens to essential minerals and amino acids during dialysis?
What happens to essential minerals and amino acids during dialysis?
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Study Notes
Functioning Systems
- The presentation is on Functioning Systems, specifically Food Assimilation, by Prof. Dr. Eman Salah Abdel-Rehim.
- The presentation covers the digestive system, digestion, types of digestion (mechanical and chemical), expressions related to mechanical digestion, the process of chemical digestion, absorption, metabolism, and the urinary system.
Learning Objectives (Food Assimilation)
- Students will understand the general function of the Digestive System.
- Students will know about Mechanical and Chemical Digestion.
- Students will understand the simplest forms of nutrients and their absorption.
- Students will learn simple outlines about Metabolism.
Functions of Digestive System
- The digestive system breaks down food into smaller molecules.
- The absorbed molecules are transported throughout the body.
- Wastes are eliminated from the body.
How the Body Gets Energy from Food
- Digestion is the process where the body breaks down food into small nutrient molecules.
- It begins in the digestive system, starting in the mouth.
Types of Digestion
-
Mechanical Digestion: Physically breaking down food.
- Begins when taking the first bite of food.
- Cutting by teeth is the first stage.
-
Chemical Digestion: The body breaks foods into smaller chemical building blocks, using chemicals.
- Begins in the mouth.
Mechanical Digestion Expressions
- Mastication: Chewing and enzymatic breakdown by saliva.
- Deglutition: Swallowing, voluntary in the mouth, and involuntary in the esophagus.
- Churning: In the stomach, forming chyme.
- Peristalsis: Contraction of circular muscle.
- Segmentation: Contraction of longitudinal muscle (backward and forward movement) to the colon.
Chemical Digestion Digestive Juices
- Saliva: From parotid, sublingual, and submandibular glands.
- Gastric Juice: Chief cells make pepsinogen, and parietal cells make HCl.
- Pancreatic Juice: Exocrine cells of the pancreas.
- Bile: Produced by the liver, stored in the gall bladder, and secreted into the small intestine aiding lipid digestion.
- Intestinal Juice: Secreted by the mucosa of the small and large intestine.
Chemical Digestion (Enzymes)
- Mouth: Carbohydrates—salivary amylase
- Stomach: Proteins—pepsin
- Small Intestine: Lipids
- Trypsin, chymotrypsin, amylase and lipase (from pancreas)
- Maltase, sucrase, lactase and peptidases (from intestinal villi)
Absorption
- After digestion, the simplest forms of food (glucose, amino acids, fatty acids) are absorbed.
- Absorption occurs through the intestinal mucosa into the blood.
- Amino acids and glucose are transported through secondary active transport.
- Fatty acids go into lymph via simple diffusion.
Metabolism
- Catabolism:
- Hydrolysis—breaks down polymers into monomers
- Cellular respiration—oxidation of monomers to yield energy
- Anabolism:
- Cell maintenance and repair
- Growth
- Formation of secretions
- Nutrient reserves
Metabolism Processes
-
Glucose
- Catabolism: glycolysis, Krebs' cycle, electron transport chain.
- Anabolism: glycogenesis, gluconeogenesis.
-
Fatty Acids
- Catabolism: Beta-oxidation, Krebs' cycle, and electron transport chain.
- Anabolism: lipogenesis
-
Amino Acids
- Catabolism: deamination, Krebs' cycle and electron transport chain.
- Anabolism: synthesis of nonessential amino acids.
Urinary System
- The presentation also introduces the urinary system.
- Learning objectives for the Urinary System include: functions of the urinary system, anatomy of the urinary system, nephron structure, urine formation (filtration, reabsorption, secretion), urine composition.
- Factors affecting kidney function are also discussed.
- Renal dialysis and transplantation as treatments for kidney diseases, as well as the date of the first human transplantation are mentioned.
Functions of the Urinary System
- Regulate blood composition and volume to maintain homeostasis.
- Disposing of metabolic wastes (urea, creatinine, ammonium, uric acid).
- Maintaining water-salt and electrolyte balance (sodium, potassium, bicarbonate).
- Maintaining acid-base balance (blood pH ≈ 7.4).
Urinary System Structure & Anatomy
- Kidneys
- Ureters
- Bladder
- Urethra
Kidney Anatomy
- Protected by fibrous tissue, fat, muscle, and ribs.
- Consists of renal cortex, medulla, and pelvis (including minor and major calyxes)
Nephron
- The structural and functional unit of the kidney.
- Composed of glomerular capsule, capillary network (glomerulus), renal tubules (proximal convoluted tubule, loop of Henle, distal convoluted tubule)
Steps in Urine Formation
- Filtration: removes water and small molecules from blood, in the renal capsule.
- Reabsorption: water and essential molecules are returned to the blood from the renal tubules.
- Secretion: wastes and excess salts are added from body fluids into the tubule fluid (urine) in the renal tubules.
Glomerular Filtration Rate (GFR)
- Amount of filtrate produced per minute by the kidneys.
- About 20% of total blood plasma—enters the kidneys every minute (approx 1000-1200ml/min).
- 625 ml plasma only pass as filtrate.
- Approximately 125-130ml of this filtrate passes through the renal tubules.
Glomerular Filtration Rate Formula:
- Calculation for GFR in liters per day.
- Kidneys can filter about 150-200 liters of plasma per day.
Forces Affecting Filtration
- Glomerular capillary hydrostatic pressure (GHP): +55 mmHg
- Blood osmotic (colloidal) pressure (BOP): -30 mmHg
- Capsular hydrostatic pressure(CHP): -15 mmHg
- Net filtration pressure: ≈+10mmHg
Reabsorption
- Reabsorption of water, nutrients, and electrolytes via different transport mechanisms through the renal tubules, primarily in the PCT, Loop of Henle , and DCT.
PCT Reabsorption — "Obligatory Reabsorption"
- Glucose and amino acids are pumped out of the tubules and also reabsorbed into the blood.
- The transporters are limited and can become saturated if glucose concentrations rise above 180 mg/dl. (Glucosuria)
PCT Reabsorption
- 70% of sodium and water are reabsorbed.
- Chloride follows sodium by simple diffusion.
- Positively charged ions draw chloride out of the filtrate.
- Some compounds present in high concentration in the filtrate go into the blood by diffusion.
Loop of Henle — Reabsorption
- Descending loop: permeable to water, water moves out of the tubule due to the osmotic gradient.
- Ascending loop: thick epithelium, impermeable to water, pumps out sodium.
So, why is the Loop of Henle useful?
- The longer the loop, the deeper it travels into the hyperosmotic medulla. This allows for more reabsorption and concentrated tubular fluid.
DCT and CT - Reabsorption “Facultative-Reabsorption"
- Reabsorption depends on the body's needs.
- DCT and CT walls have tight junctions, impermeable to water.
- Cells have ADH (antidiuretic hormone) and Aldosterone receptors that modify water/ion permeability according to needs
Regulation of ADH Secretion
- ADH increases water retention reducing urine volume and prevents dehydration.
- Affected by decreased blood volume and blood pressure by Baroreceptors and increased salt concentration by Osmoreceptors.
DCT and CT Reabsorption (Urine Concentration)
- Late distal tubule is impermeable to water, with low ADH.
- When ADH is released from the posterior pituitary, aquaporin channels open. More water is thus absorbed.
Secretion and Excretion
- Secretion: Selective transport of molecules from blood in peritubular capillaries into filtered fluid in the tubular lumen.
- Waste products like urea, excess metabolites, K+, H+, and Ca++
- Excretion: The body removes urine (molecules dumped outside the tubules).
Urine Formation Summary
- Key stages and direction of urine formation, as well as proportion of amount in different stages.
Urine Composition
- 95-96% water
- Urea, uric acid, amino acids, electrolytes
Daily Urine Production
- Average urine production (600ml-2500ml/day)
Factors Affecting Kidney Function
- ADH: prevents excess water loss.
- Alcohol: inhibits ADH secretion, more urine volume, and diluted.
- Aldosterone: prevents sodium and water loss.
- Caffeine: increases the rate of salt and water loss.
- Increased blood pressure: increases the rate of water loss.
Kidney Diseases
- Affect structure and function through stages, which can lead to failure.
- Kidney failure is fatal, but it can be treated by dialysis or transplantation.
- Kidney is the first successfully transplanted organ in humans (1954).
Hemodialysis
- A treatment for people with kidney failure.
- The kidneys filter the blood, removing wastes and toxins.
- Dialysis works by using a dialyzer with a thin membrane to separate the patient's blood from a dialysis solution.
- Waste products move from the blood into the dialysis solution by diffusion due to the concentration gradient.
- Essential minerals and amino acids move from the dialysis solution into the blood.
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Description
This quiz explores the functioning systems involved in food assimilation as presented by Prof. Dr. Eman Salah Abdel-Rehim. Delve into the intricacies of the digestive system, including mechanical and chemical digestion, nutrient absorption, metabolism, and the urinary system. Enhance your understanding of how the body processes food and extracts energy.
