Digestive System Quiz

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Questions and Answers

What is the primary function of the large intestine?

Digestion of proteins

Initial breakdown of starch

Transportation of food to the stomach

Absorption of water and minerals (correct)

Which of the following statements best describes the role of accessory organs in digestion?

They assist in the mechanical and chemical breakdown of food. (correct)

They include structures like the mouth and esophagus.

They are part of the gastrointestinal tract.

They solely transport food through the digestive system.

Which nutrient is primarily absorbed in the small intestine?

Starches

Proteins (correct)

Water

Minerals

What mechanism prevents food from entering the respiratory tract during swallowing?

Elevation of the larynx Signup and view all the answers

What process facilitates the movement of a bolus through the esophagus?

Peristalsis Signup and view all the answers

In which part of the digestive system does the activation of pepsin most significantly occur?

Stomach Signup and view all the answers

Which of the following is NOT a function of the stomach?

Absorbing carbohydrates Signup and view all the answers

What role does saliva play in the process of digestion?

It moistens and lubricates food. Signup and view all the answers

Which accessory organ secretes bile for fat emulsification?

Liver Signup and view all the answers

Which structure connects the small intestine to the large intestine?

Cecum Signup and view all the answers

Which of the following is NOT a role of the pancreas in digestion?

Secreting bile salts Signup and view all the answers

What is the importance of villi and microvilli in the small intestine?

To increase surface area for absorption Signup and view all the answers

What is synthesized by bacteria in the large intestine?

Vitamin K Signup and view all the answers

Which process occurs when food in the duodenum stimulates the gallbladder?

Contraction to release bile Signup and view all the answers

What are the three parts of the small intestine?

Duodenum, jejunum, and ileum Signup and view all the answers

What role does insulin play in blood glucose regulation after a carbohydrate-rich meal?

Promotes the removal of excess blood glucose by the liver and skeletal muscles Signup and view all the answers

How do gases like oxygen and carbon dioxide exchange in vertebrates?

Through diffusion influenced by concentration gradients Signup and view all the answers

What initiates the increase in breathing rate when blood PCO2 rises?

Stimulation of chemosensitive neurons by lowered blood pH Signup and view all the answers

What is the main function of the alveoli in mammalian lungs?

To facilitate gas exchange between air and blood Signup and view all the answers

What occurs during inhalation to increase thoracic volume?

Contraction of external intercostal and diaphragm muscles Signup and view all the answers

What substance in red blood cells binds and transports oxygen?

Hemoglobin Signup and view all the answers

What is the result of glycogenolysis in the liver?

Release of glucose into the blood Signup and view all the answers

Which two muscle sets are primarily involved in increasing thoracic volume during inhalation?

External intercostal and diaphragm muscles Signup and view all the answers

Study Notes

The Digestive System

The digestive system involves a tubular gastrointestinal tract and accessory organs.
The mouth and pharynx are the entry points for food.
The esophagus delivers food to the stomach.
The stomach is responsible for preliminary digestion.
The small intestine is for digestion and absorption.
The large intestine absorbs water and minerals.
The cloaca or rectum expels waste.

Vertebrate Digestive Systems

The digestive system is a tubular gastrointestinal tract with accessory organs.
Mouth and pharynx (throat) are the entryways.
The esophagus delivers food to the stomach.
The stomach begins the digestive process.
The small intestine digests and absorbs nutrients.
The large intestine reabsorbs water and minerals.
A cloaca or rectum expels waste.

Mouth and Teeth

The tongue mixes food with saliva within the mouth.
Saliva moistens and lubricates food.
Saliva contains amylase, which digests starch.
Salivation is a nervous system process.
Tasting, smelling, and thinking about food increases saliva production.

Swallowing

Swallowing begins as a voluntary action.
Swallowing becomes involuntary as the process continues.
During swallowing, the tongue pushes food to the back of the mouth.
The soft palate seals off the nasal cavity.
The larynx (voice box) elevates and the epiglottis covers the trachea.
This prevents food from entering the respiratory tract.

The Esophagus

A muscular tube connecting the esophagus to the stomach.
Peristalsis moves a bolus (food mass) through the esophagus.
The swallowing center in the brain initiates wave-like muscle contractions.

The Stomach

A sac-like part of the digestive tract.
The convoluted surface area allows expansion.
The stomach contains mucus-secreting cells.
Parietal cells secrete hydrochloric acid (HCl).
Chief cells secrete pepsinogen (inactive form of pepsin).
Pepsinogen converts to pepsin to digest protein.
Low pH in the stomach denatures proteins and activates pepsin.
Little carbohydrate or fat digestion occurs in the stomach.
Absorption of some water (such as alcohol and aspirin) happens in the stomach.
Chyme (partially digested food and gastric juice mix) leaves the stomach through the pyloric sphincter.

The Small Intestine

Approximately 4.5 meters long with a small diameter.
Composed of three sections: duodenum, jejunum, and ileum.
Receives chyme (partially digested food) from the stomach.
Receives digestive enzymes and bicarbonate from the pancreas.
Receives bile from the liver and gallbladder.
The epithelial lining is covered with villi.
Villi are covered with microvilli which increases the surface area for absorption.

The Large Intestine (Colon)

Much shorter than the small intestine but has a larger diameter.
Empties into the large intestine at a junction where the cecum and appendix remain.
No digestion occurs here.
Absorbs water, electrolytes, and vitamin K.
Prepares waste for expulsion.
Bacteria in the large intestine synthesize vitamin K.

Accessory Organs

The pancreas secretes pancreatic fluid into the duodenum through the pancreatic duct.
Enzymes such as trypsin and chymotrypsin break down proteins.
Pancreatic amylase digests polysaccharides.
Lipase breaks down fats into fatty acids and monoglycerides.
Bicarbonate neutralizes acidic chyme.
The liver is the largest internal organ.
It produces bile (bile pigments and salts).
Bile emulsifies fats.
The liver metabolizes alcohol, drugs, toxins, pesticides and carcinogens.
The gallbladder stores and concentrates bile.
Arrival of fatty food in the duodenum signals gallbladder contraction to release bile.

Accessory Organ Function

Regulates blood glucose after a carbohydrate-rich meal.
Insulin removes excess glucose, converting it to glycogen and storing it in the liver and skeletal muscles.
When blood glucose levels are low, glycogenolysis triggers glucagon release to break down glycogen for glucose release in the blood.

Circulation

Mammals, birds, and crocodilians have a four-chambered heart with two atria and two ventricles.
The right atrium receives deoxygenated blood from the body and pumps it to the lungs via the right ventricle.
The left atrium receives oxygenated blood from the lungs and pumps it to the body via the left ventricle.

The Cardiac Cycle

Valves open and close throughout the cardiac cycle.
Relaxed ventricles fill with blood (diastole)
Contracted ventricles pump blood (systole)
Lub-dub sounds are heard with a stethoscope due to heart valve closure.
Lub comes from AV valves closing.
Dub comes from semilunar valve closing.

Blood Vessels

Arteries and veins consist of four tissue layers.
Arteries have thicker walls and smooth muscle compared to veins.
Capillaries contain a single layer of endothelial cells which allows rapid exchange of gases and metabolites between the blood and the body cells.
Arteries and arterioles have more elastic fibers and thicker smooth muscle compared to veins.
Veins and venules have a thinner layer of smooth muscle compared to arteries.
Skeletal muscle contractions and one-way venous valves facilitate blood return to the heart.
Capillaries have a large total cross-sectional area allowing for exchange with extracellular fluid and slowing blood flow for optimal exchange.
Blood vessels transport blood throughout the body.
Blood from the body enters the right atrium through the superior and inferior vena cava.
Oxygenated blood leaves the heart through the aorta, including coronary arteries which supply oxygenated blood to the heart muscle.
Right and left pulmonary arteries deliver deoxygenated blood to the lungs.
Pulmonary veins return oxygenated blood from the lungs to the left atrium.

Lung Structure and Function

Lungs are packed with alveoli (gas exchange sites).
Inhaled air travels through the larynx, glottis, trachea, bronchi, bronchioles to the alveoli.
Alveoli are surrounded by capillaries for efficient gas exchange.
Inhalation increases thoracic volume due to external intercostal and diaphragm contraction creating a negative pressure.

Blood

Blood is a connective tissue with a fluid matrix (plasma) and formed elements.
Blood plasma contains water, proteins, and other dissolved substances.
The formed elements include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets.
Red blood cells carry oxygen.
White blood cells fight infection.
Platelets are involved in blood clotting.

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Description

Test your knowledge on the human digestive system with this quiz. Answer questions about the functions of various organs, the absorption of nutrients, and the processes involved in digestion. Perfect for biology students wanting to master the topic.