Physio L1C | Organization and Regulation of the GI Tract

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What is the main purpose of the alimentary tract?

Production of red blood cells

Absorption of oxygen and carbon dioxide

Absorption of water, electrolytes, vitamins, and digestive products (correct)

Movement of blood through the alimentary tract

What are the characteristics of gastrointestinal smooth muscle fibers?

250 to 500 micrometers in diameter

Arranged in bundles of 1000 parallel fibers (correct)

500 to 1000 micrometers in diameter

2 to 10 micrometers in length

What is one of the objectives regarding the GI tract organization and functioning?

Comprehending the role of the Endocrine system

Understanding the general arrangement of the nervous system

Recognizing the characteristics associated with skeletal muscle

Knowing the basic physiology behind the GI tract (correct)

How does the alimentary tract provide the body with a continual supply of nutrients?

By circulation of blood flow through the gastrointestinal organs Signup and view all the answers

What is the role of the Nervous system in the organization and functioning of the GI tract?

To regulate digestion and absorption in the GI tract Signup and view all the answers

What is required for the purpose of secretion of digestive juices and digestion of the food?

Movement of food through the alimentary tract Signup and view all the answers

Which of the following is NOT a stimulus for the secretion of cholecystokinin?

Carbohydrate Signup and view all the answers

In the GI tract, which hormone stimulates gastric emptying?

Motilin Signup and view all the answers

Which site secretes gastric inhibitory peptide?

K cells of the jejunum Signup and view all the answers

What is the role of secretin in the GI tract?

Stimulates pancreatic enzyme secretion (bicarb into lumen of duodenum) Signup and view all the answers

Which statement about smooth muscle contraction in the GI tract is false?

Muscle layers in the GI tract wall do not share electrical connections Signup and view all the answers

What type of stimuli are needed for the secretion of motilin?

Fat, acid, nerve Signup and view all the answers

Which hormone inhibits gastric acid secretion?

Gastric Inhibitory Peptide Signup and view all the answers

Where are the S cells located that secrete cholecystokinin?

I cells of the duodenum, jejunum, and ileum. Signup and view all the answers

What is inhibited by secretin?

Gastric acid secretion Signup and view all the answers

What are the stimuli for the secretion of gastric inhibitory peptide?

Protein, fat, carbohydrate Signup and view all the answers

What is the main reason for the low resistance movement of ions from one muscle cell to the next?

Existence of gap junctions Signup and view all the answers

Which type of electrical waves are slow, undulating changes in the resting membrane potential?

Slow waves Signup and view all the answers

What causes smooth muscle contraction in response to entry of calcium ions into the muscle fiber?

Activation of myosin filaments Signup and view all the answers

How many plexus are present in the enteric nervous system, and what are their respective functions?

Two plexus: One for controlling gastrointestinal movements and another for gastrointestinal secretion and local blood flow Signup and view all the answers

Which stimuli can activate afferent sensory nerve fibers?

Irritation of the gut mucosa Signup and view all the answers

What is the main effect of parasympathetic stimulation on the enteric nervous system?

General increase in activity of the entire enteric nervous system Signup and view all the answers

What is the function of slow waves in intestinal smooth muscle?

Rhythmically determine the frequency and intensity of contraction Signup and view all the answers

Which factor causes hyperpolarization of the membrane, making it more difficult to depolarize?

Stimulation by norepinephrine or epinephrine in the fiber membrane Signup and view all the answers

What is a characteristic feature of tonic contraction in intestinal smooth muscle?

Continuous partial depolarization causing tonic contraction Signup and view all the answers

Which type of reflexes are controlled entirely within the gut wall, integrating gastrointestinal secretion, peristalsis, mixing, contractions, and local inhibitory effects?

Short distance reflexes Signup and view all the answers

Which stimuli can cause increased secretion of gastrin?..

Protein, distension, and nerve stimulation Signup and view all the answers