Human Digestive System Lecture 2

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Questions and Answers

What does absorption refer to in the digestive process?

The breakdown of food into simpler molecules

The movement of molecules into the blood and lymphatic vessels (correct)

The elimination of waste from the body

The secretion of digestive enzymes

Which of the following describes hyperglycemia?

A condition of low blood sugar levels

Presence of glucose in the urine

An increase in blood sugar concentration (correct)

A tumor resulting in high insulin production

What is the primary role of carbohydrates in human nutrition?

To transport oxygen in the bloodstream

To aid in the digestion of proteins

To serve as the main source of energy (correct)

To provide structural support in cells

Which monosaccharide is known as a hexose?

Galactose Signup and view all the answers

What occurs during defecation?

The elimination of undigested material Signup and view all the answers

In which condition is there a decreased secretion of insulin?

Hypoinsulinism Signup and view all the answers

Which of the following carbohydrates is primarily found in plant cells?

Cellulose Signup and view all the answers

Which condition results from the presence of glucose in the urine?

Glucosuria Signup and view all the answers

Which organs are primarily responsible for carbohydrate storage in the body?

Liver and muscle Signup and view all the answers

How long can the body's stored carbohydrate typically meet energy needs?

One-half day Signup and view all the answers

Which of the following tissues is the most important consumer of glucose?

Brain Signup and view all the answers

What is gluconeogenesis?

The process of converting amino acids into glucose Signup and view all the answers

What hormone is essential for facilitating glucose transfer into cells?

Insulin Signup and view all the answers

Which cells depend almost entirely on glucose for energy under fasting conditions?

Glucose-dependent cells Signup and view all the answers

What metabolic process helps maintain blood glucose levels during fasting?

Gluconeogenesis Signup and view all the answers

Which of the following is NOT a source of gluconeogenesis?

Sucrose Signup and view all the answers

What is the storage form of carbohydrates in plants?

Starch Signup and view all the answers

Which polysaccharide acts as an anticoagulant and is stored in mast cells?

Heparin Signup and view all the answers

Which of the following is a characteristic of glycogen?

Highly branched and stored in liver and skeletal muscle Signup and view all the answers

What role does cellulose play in the diet?

Indigestible fiber aiding in bowel elimination Signup and view all the answers

Which property makes inulin a good index for assessing glomerular filtration rate (GFR)?

It is not altered, reabsorbed, or secreted in the body Signup and view all the answers

What is the normal concentration of glucose in the blood?

100 mg/dl Signup and view all the answers

Which of the following sugars is the sweetest and most soluble?

Fructose Signup and view all the answers

What is galactose primarily derived from?

Lactose hydrolysis Signup and view all the answers

Which condition is associated with the inability to metabolize fructose?

Fructosemia Signup and view all the answers

Which disaccharide is composed of glucose and galactose?

Lactose Signup and view all the answers

What is the primary composition of maltose?

Two glucose units Signup and view all the answers

Polysaccharides are primarily characterized by being:

Very long chains of monosaccharides Signup and view all the answers

What condition is associated with glucose excretion in urine?

Diabetes Mellitus Signup and view all the answers

What is the normal fasting blood sugar (FBS) level considered to be?

< 100 mg/dl Signup and view all the answers

What condition is assessed using Random Blood Sugar (RBS) testing?

Insulin shock or hyperglycemic ketonic coma Signup and view all the answers

What does a Hemoglobin A1c (HbA1c) level of 6.5% or higher indicate?

Diabetes Signup and view all the answers

What parameter is used to diagnose gestational diabetes during pregnancy?

Oral Glucose Tolerance Test (OGTT) Signup and view all the answers

What is the significance of a blood sugar level of ≤ 60 mg/dl?

Strongly suggests hypoglycemia Signup and view all the answers

What are symptoms of hypoglycemia that may appear around 50-55 mg/dl?

Increased hunger and sweating Signup and view all the answers

Which type of carbohydrate cannot be hydrolyzed into simpler sugars?

Monosaccharides Signup and view all the answers

Which of the following is the normal value range for a 2-hour postprandial blood sugar test (2-HPPBS)?

≤ 140 mg/dl Signup and view all the answers

Study Notes

Digestive Processes

Absorption: Movement of molecules via passive diffusion or active transport from the digestive tract to blood and lymphatic vessels; crucial for entering digested food into the body.
Defecation: Elimination of undigested materials through the anus.

Carbohydrates Overview

Composed of hydrogen, carbon, and oxygen.
Major dietary component and important energy source for the body.
Stored primarily as glycogen in muscles (0.5% of wet weight) and the liver (up to 10% of wet weight).
Total glycogen storage supports energy needs for about half a day.

Key Terms

Hyperglycemia: Elevated glucose levels in the blood.
Hypoglycemia: Reduced glucose levels in the blood.
Glycosuria: Presence of glucose in urine.
Hyperinsulinism: Increased secretion of insulin.
Hypoinsulinism: Decreased secretion of insulin.
Insulinoma: Tumor in the pancreas causing increased insulin production.

Carbohydrate Classification

Based on the number of carbon atoms: triose (3), tetrose (4), pentose (5), hexose (6).
Monosaccharides (simple sugars) include glucose, fructose, and galactose; significant in nutrition.
Dietary carbohydrates exist mainly as sugars and starches.

Glucose Utilization

Glucose is the principal carbohydrate in blood and a primary energy source for glucose-dependent cells like the brain, red blood cells, and others.
Under fasting conditions, gluconeogenesis occurs, using proteins from muscles to generate glucose.
Liver gluconeogenesis is crucial for maintaining blood glucose levels during fasting.

Diabetes Mellitus

Associated with inadequate insulin levels, affecting glucose transport into cells.
Brain is particularly vulnerable to low blood sugar levels.

Laboratory Tests for Carbohydrate Metabolism

FBS (Fasting Blood Sugar): Required fasting for 6-8 hours; normal value < 100 mg/dl.
RBS (Random Blood Sugar): Collected anytime; normal value < 140 mg/dl.
2-HPPBS (2-hour Post Prandial Blood Sugar): Monitors insulin response; normal value < 140 mg/dl.
HbA1c: Indicates average glucose levels over 2-4 months; normal < 5.7%.
OGTT/IVGTT: Tests for gestational diabetes.

Normal Value Ranges for Blood Sugar

Hyperglycemic hormone release at 65-70 mg/dl.
Hypoglycemia suggested at ≤ 60 mg/dl.
Symptoms of hypoglycemia may appear at around 50-55 mg/dl.

Functions of Carbohydrates

Serve as major energy sources.
Structural components in biological systems.
Function as energy reserves, sparing proteins during metabolism.

Polysaccharides Classification

Starch: Storage form in plants, consisting of amylose (linear) and amylopectin (branched).
Glycogen: Storage form in animals, highly branched structure.
Cellulose: Indigestible polysaccharide aiding bowel movement.

Examples of Sugars

Glucose: Blood sugar with a normal concentration < 100 mg/dl; excess is converted to glycogen or fat.
Fructose: Found in honey, sweetest of sugars; related condition: fructosemia.
Galactose: Present in glycoproteins; related condition: galactosemia.

Disaccharides

Lactose: Composed of glucose and galactose; found in milk.
Maltose: Contains two glucose units; forms during starch digestion.
Sucrose: Composed of glucose and fructose; known as table sugar.

Understanding carbohydrates helps in grasping their role in nutrition, energy regulation, and their impact on health conditions like diabetes.

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Description

This quiz focuses on the processes involved in the human digestive system, specifically on absorption and defecation. Learn how enzymes function within the stomach and small intestines, and understand how nutrients enter the bloodstream. Test your knowledge on the processes that lead to the elimination of waste.