Respiratory and Digestive Overview

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Questions and Answers

What role does the nose play in the respiratory system?

Regulating blood flow

Producing oxygen

Filtering and warming air (correct)

Conducting sound waves

Which structure is primarily responsible for trapping dust and allergens in the nose?

Mucous membranes

Conchae

Nasal septum

Cilia (correct)

Which part of the upper respiratory tract is responsible for connecting to the middle ear?

Oropharynx

Nasopharynx

Eustachian tubes (correct)

Larynx

What is the function of the paranasal sinuses?

To lighten the skull and provide voice resonance Signup and view all the answers

What feature of the nasal cavity increases the surface area for air to be warmed and humidified?

Conchae Signup and view all the answers

What is the main purpose of the mucous membranes lining the nasal cavities?

To trap bacteria and particles Signup and view all the answers

Where are olfactory receptors primarily located?

Upper nasal cavities Signup and view all the answers

Which part of the pharynx serves as an air passageway only?

Nasopharynx Signup and view all the answers

What is the primary location for nutrient absorption in the digestive system?

Small intestine Signup and view all the answers

Which of the following statements is true regarding saliva?

Saliva secretion is continuous but increases with the presence of food. Signup and view all the answers

Which structure acts to prevent backflow of food from the stomach into the esophagus?

Lower esophageal sphincter (LES) Signup and view all the answers

What type of digestion involves physically breaking down food into smaller pieces?

Mechanical digestion Signup and view all the answers

Which enzyme is secreted in its inactive form and gets activated in the stomach?

Pepsinogen Signup and view all the answers

The pyloric sphincter controls the passage of what substance into the duodenum?

Chyme Signup and view all the answers

What structure do taste buds reside in?

Papillae Signup and view all the answers

Which layer of the alimentary tube contains blood vessels and lymphatic vessels?

Submucosa Signup and view all the answers

What is the main function of the gastric pits in the stomach?

Secretion of gastric juice Signup and view all the answers

Which organ is responsible for the production of bile?

Liver Signup and view all the answers

What role does the medulla play during swallowing?

Coordinates muscle contraction of the pharynx Signup and view all the answers

Which part of the small intestine is primarily involved in the completion of digestion?

Duodenum Signup and view all the answers

What happens when the lower esophageal sphincter fails to close properly?

Gastroesophageal reflux occurs Signup and view all the answers

What is the primary function of the large intestine?

Eliminate undigested material Signup and view all the answers

Which cell type in the small intestine secretes mucus?

Goblet cells Signup and view all the answers

What is the primary function of bile?

Emulsifies fats Signup and view all the answers

Which hormone stimulates bile production in the liver when food enters the small intestine?

Secretin Signup and view all the answers

What is the role of the gallbladder?

Stores and concentrates bile Signup and view all the answers

Where does the majority of nutrient absorption occur?

Small intestine Signup and view all the answers

What is the function of the taenia coli in the large intestine?

Gathers the colon into haustra Signup and view all the answers

What regulates the blood glucose level in the liver?

Carbohydrate metabolism Signup and view all the answers

Which pancreatic enzyme is responsible for lipid digestion?

Lipase Signup and view all the answers

What is found in the capillaries surrounding the villi of the small intestine?

Nutrients and lacteals Signup and view all the answers

What triggers the defecation reflex?

Stretch receptors in the rectum Signup and view all the answers

Which vitamin is produced by the normal flora in the large intestine?

Vitamin K Signup and view all the answers

Which part of the large intestine is connected to the ileum?

Cecum Signup and view all the answers

What type of muscle is the internal anal sphincter made of?

Smooth muscle Signup and view all the answers

What is produced from the breakdown of old red blood cells in the liver?

Bilirubin Signup and view all the answers

What is the primary function of the palatine tonsils?

Protecting the pharynx from pathogens Signup and view all the answers

Which structure is responsible for preventing food from entering the airway during swallowing?

Epiglottis Signup and view all the answers

Which of the following statements about the trachea is correct?

It is lined with ciliated epithelium and goblet cells Signup and view all the answers

What is the role of alveoli in the respiratory system?

Gas exchange Signup and view all the answers

Which of the following best describes the function of pulmonary surfactant?

It reduces surface tension to allow alveoli expansion Signup and view all the answers

What is the primary function of alveoli in the lungs?

Gas exchange Signup and view all the answers

Where do the primary bronchi lead after branching from the trachea?

Into the lungs Signup and view all the answers

What type of epithelium lines the alveoli, and why is this significant?

Simple squamous epithelium for efficient gas diffusion Signup and view all the answers

What role does pulmonary surfactant play in the respiratory system?

Reduces surface tension Signup and view all the answers

Which part of the respiratory system only serves as an air passageway?

Nasopharynx Signup and view all the answers

Which pressure is always slightly below atmospheric pressure during ventilation?

Intrapleural pressure Signup and view all the answers

What is the main purpose of the pleural membranes?

Preventing friction during breathing Signup and view all the answers

What happens to the intrapulmonic pressure during inhalation?

It decreases below atmospheric pressure Signup and view all the answers

Which of the following structures does not contribute to voice production?

Bronchi Signup and view all the answers

Which muscles primarily contract during normal inhalation?

Diaphragm and external intercostal muscles Signup and view all the answers

What happens to the larynx during swallowing?

It elevates to prevent airway obstruction Signup and view all the answers

Which of the following describes tidal volume?

The amount of air involved in one normal breath Signup and view all the answers

Which cartilage is the largest in the larynx?

Thyroid cartilage Signup and view all the answers

What is the usual pH range of normal human blood?

7.35 to 7.45 Signup and view all the answers

Which feature of the trachea allows it to maintain its structure?

C-shaped cartilage rings Signup and view all the answers

How does aging affect the respiratory system?

Weakens respiratory muscles Signup and view all the answers

What triggers the coughing reflex?

Irritation of the mucosa in the pharynx Signup and view all the answers

What is the purpose of the mucosa lining in the nasal cavities?

To trap and clear dust and particles Signup and view all the answers

What is the primary effect of increased carbon dioxide in the blood?

It serves as a major regulator of respiration Signup and view all the answers

What is considered forced expiration?

Contraction of the internal intercostal muscles Signup and view all the answers

What is the main role of chemoreceptors in the respiratory system?

Monitor blood gas levels and pH Signup and view all the answers

What is the key characteristic of residual air in the lungs?

It is the amount of air after maximum exhalation Signup and view all the answers

Which respiratory center in the brain prolongs inhalation?

Apneustic center Signup and view all the answers

Study Notes

Respiratory System: Anatomy

The nose filters, warms, and humidifies air before it reaches the lungs.
Nasal cavities are separated by the septum.
The upper respiratory tract includes the nose, nasal cavities, pharynx, larynx, and upper trachea.
The lower respiratory tract contains the lower trachea, lungs (bronchial tubes and alveoli).
The pharynx is a muscular tube that connects the nasal and oral cavities to the cervical vertebrae.
The nasopharynx acts as an air passageway only.
The oropharynx is a passageway for both food and air.
The laryngopharynx serves as a passageway for both food and air.
The larynx (voice box) is an air passageway between the pharynx and trachea.
The trachea extends from the larynx to the primary bronchi.
The bronchial tree is a branching system that carries air into the lungs.
Alveoli are tiny air sacs at the end of the bronchioles responsible for gas exchange.
Lungs are located on either side of the heart and are enclosed by the rib cage.
Pleural membranes are serous membranes in the thoracic cavity that help keep the lungs in place and prevent friction during breathing.
Alveoli are made of simple squamous epithelium, surrounded by elastic connective tissue and capillaries, and lined with tissue fluid.
Pulmonary surfactant reduces surface tension in the alveoli.

Ventilation

Ventilation is the movement of air into and out of the alveoli.
Inhalation involves the contraction of the diaphragm and external intercostal muscles, which expands the chest cavity.
Exhalation is typically passive and results from the relaxation of the diaphragm and external intercostal muscles.
Forced exhalation involves the contraction of the internal intercostal muscles.

Pulmonary Volumes

Tidal volume is the amount of air moved in one normal breath.
Minute respiratory volume is the amount of air inhaled and exhaled in one minute.
Inspiratory reserve volume is the amount of air that can be inhaled beyond tidal volume.
Expiratory reserve volume is the amount of air that can be exhaled beyond tidal volume.
Vital capacity is the total amount of air that can be exhaled after a maximal inhalation.
Residual volume is the amount of air that remains in the lungs after a maximal exhalation.

Respiration

External respiration is the exchange of gases between the alveoli and the blood in the pulmonary capillaries.
Internal respiration is the exchange of gases between the blood in systemic capillaries and the tissues of the body.

Nervous Regulation

The medulla oblongata automatically generates impulses to stimulate the respiratory muscles.
Baroreceptors detect lung stretching and inhibit the inspiration center.
The expiration center contributes to forceful exhalation.

Respiratory Centers in the Pons

The apneustic center prolongs inhalation.
The pneumotaxic center contributes to exhalation.

Hypothalamus and Cerebral Cortex

The hypothalamus modifies breathing rate during emotional stress.
The cerebral cortex enables voluntary control of breathing.

Coughing and Sneezing

Both coughing and sneezing are controlled by the medulla.
Coughing is stimulated by irritation of the mucosa in the pharynx, larynx, or trachea.
Sneezing is stimulated by irritation of the nasal mucosa.

Chemical Regulation

Chemoreceptors detect changes in blood gases and pH.
Hypoxia (low oxygen levels) increases respiratory rate.
Excess carbon dioxide lowers blood pH and increases respiratory rate.

Acid-Base Balance

Respiratory acidosis occurs when there is a decrease in the rate or efficiency of respiration.
Respiratory alkalosis occurs when there is an increase in the rate of respiration.
Metabolic acidosis is caused by factors other than the respiratory system and leads to an increase in hydrogen ions.
Metabolic alkalosis is caused by factors other than the respiratory system and leads to a decrease in hydrogen ions.

Aging and the Respiratory System

Respiratory muscles weaken with age.
Lung tissue and alveoli lose elasticity.
Cilia deteriorate with age.
Macrophages become less efficient.
Chronic respiratory diseases like emphysema and bronchitis are more common in the elderly.
Hypertension can lead to an overworked left ventricle and heart failure.

Digestive System Divisions

The alimentary tube is a continuous tube extending from the mouth to the anus.
Digestion primarily occurs in the oral cavity, stomach, and small intestine.
Absorption primarily takes place in the small intestine.
Accessory organs aid in digestion and include the teeth, tongue, salivary glands, liver, gallbladder, and pancreas.

Mechanical vs. Chemical Digestion

Mechanical digestion physically breaks down food.
Chemical digestion changes complex molecules into simpler ones that the body can use.

Oral Cavity

The oral cavity is the entrance to the digestive system, containing teeth, tongue, and openings to salivary gland ducts.
Teeth provide mechanical digestion by breaking down food.
The tongue mixes food with saliva and keeps food between the teeth.
Salivary glands produce saliva, a mixture mainly of water and digestive enzymes.

Pharynx

The oropharynx and laryngopharynx are food passageways connecting the oral cavity to the esophagus.
No digestion occurs in the pharynx.
The medulla coordinates swallowing, including contraction of the pharynx muscles, cessation of breathing, elevation of the soft palate, and closure of the epiglottis.

Esophagus

The esophagus is a muscular tube connecting the pharynx to the stomach.
No digestion occurs in the esophagus.
Peristalsis propels food towards the stomach.
The lower esophageal sphincter (LES) prevents backflow of stomach contents.

Layers of the Alimentary Tube

The mucosa is the innermost layer, containing epithelium, lymph nodules, and the Meissner's plexus.
The submucosa contains blood vessels, lymphatic vessels, and the Meissner's plexus.
The muscularis contracts to break up food and mix it with digestive juices.
The serosa, the outermost layer, is made up of the mesentery and peritoneum.

Stomach

The stomach is a J-shaped organ located in the upper left quadrant of the abdominal cavity.
The stomach acts as a reservoir for food and carries out both mechanical and chemical digestion.### Stomach
The stomach is a muscular, J-shaped organ that functions in food storage and initial digestion
Divided into three main sections: fundus, body, and pylorus.
The fundus and body are primarily responsible for storage.
The pylorus is the lower section, connecting to the duodenum and responsible for digestion.
The pyloric sphincter controls the passage of chyme (churned food) into the duodenum.
Rugae are folds lining the stomach, allowing it to expand.
Gastric pits are glands that secrete gastric juice, essential for digestion.
Mucous glands protect the stomach lining from acidic gastric juices.
Chief cells produce pepsinogen, an inactive form of pepsin, which is activated by hydrochloric acid.
Pepsin digests proteins.
Parietal cells secrete hydrochloric acid (highly acidic, pH 1-2) that activates pepsinogen and kills microorganisms.
Parietal cells also produce intrinsic factor, crucial for vitamin B12 absorption.
The sight or smell of food stimulates gastric juice secretion.
Gastrin, a hormone produced by G cells, stimulates gastric juice production.
Three layers of smooth muscle churn and mix food.
The pyloric sphincter contracts during churning but relaxes periodically to release chyme.

Small Intestine

The small intestine is a long, narrow tube responsible for completing digestion and absorbing nutrients.
It's approximately 20 feet long and 1 inch in diameter, extending from the stomach to the large intestine.
Divided into three sections: duodenum, jejunum, and ileum.
The duodenum is the first 10 inches, where the common bile duct enters.
The jejunum is 8 feet long, and the ileum is about 11 feet long.
The mucosa of the small intestine contains specialized cells:
- Cells with microvilli increase surface area for absorption.
- Goblet cells secrete mucus for lubrication.
- Enteroendocrine cells produce hormones.
- Peyer's patches (lymph nodules in the ileum) destroy absorbed pathogens.
The external muscle layer mixes chyme with digestive secretions and propels it towards the colon.

Liver

The liver is a large, vital organ located in the upper right and center of the abdominal cavity.
Divided into two lobes (right and left).
The liver lobule is the functional unit of the liver.
Hepatic arteries and portal veins branch within the liver.
Sinusoids are large capillaries within the liver.
The liver's primary digestive function is the production of bile.
Bile is secreted into small bile ducts, which merge to form the hepatic duct.
The hepatic duct carries bile out of the liver.
Bile is composed mainly of water, bilirubin, and cholesterol.
Bile salts emulsify fats in the small intestine, aiding in fat digestion.
The hormone secretin, produced in the duodenum, stimulates bile production.
The liver also regulates blood glucose and amino acids, stores vitamins, and detoxifies the blood.

Gallbladder

The gallbladder is a small, pear-shaped organ attached to the underside of the liver's right lobe.
Bile flows from the hepatic duct into the cystic duct and then into the gallbladder.
It stores and concentrates bile by absorbing water.
The hormone cholecystokinin signals the gallbladder to contract, releasing bile into the cystic duct and duodenum upon food entering the duodenum.

Pancreas

The pancreas is located in the upper left abdominal quadrant.
Secretes pancreatic enzymes:
- Amylase digests starch into maltose.
- Lipase digests emulsified fats into fatty acids and glycerol.
- Trypsin digests polypeptides into shorter amino acid chains.
Pancreatic juice is transported through ducts to the pancreatic duct, which connects to the common bile duct in the duodenum.
The pancreas also produces bicarbonate juice, neutralizing gastric acid in the duodenum.

Absorption

Most absorption of digested nutrients occurs in the small intestine, facilitated by:
- Plica circularis (circular folds)
- Villi
- Microvilli (folds of the small intestine's mucosa)
Each villus contains a capillary network and a lacteal (lymph capillary).
Nutrients are absorbed into the blood through the capillaries surrounding the villi.
Blood from the villi travels to the liver through the portal vein.

Large Intestine (Colon)

The large intestine (colon) is a wider tube approximately 5 feet long, extending from the ileum to the anus.
It's divided into sections: cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anal canal.
No digestion occurs in the large intestine.
Mucus provides lubrication.
Taenia coli (bands of longitudinal smooth muscle) gather the large intestine into pouches called haustra.
The large intestine harbors normal flora (bacteria) that produce Vitamin K, which is absorbed.
It absorbs water, minerals, and vitamins.
Undigested material forms feces.

Defecation

Defecation is the elimination of feces.
Feces consist of undigested material, dead and living bacteria, and water.
The defecation reflex is a spinal cord reflex controlled voluntarily.
Peristalsis moves feces into the rectum.
Stretch receptors in the rectum trigger the defecation reflex.
The internal anal sphincter relaxes during defecation.
The external anal sphincter (skeletal muscle) controls voluntary closure of the anus.
Diarrhea occurs when water is not absorbed adequately in the large intestine, resulting in loose stools.

Liver Functions

The liver performs numerous essential functions:
- Carbohydrate metabolism: Regulates blood glucose levels, converts excess sugar to glycogen, and converts glycogen to glucose.
- Amino acid metabolism: Regulates blood amino acid levels and produces amino acids for protein synthesis.
- Lipid metabolism: Synthesizes plasma proteins (e.g., albumin) to maintain blood volume.
- Formation of bilirubin: Macrophages in the liver break down old red blood cells, producing bilirubin from hemoglobin.
- Phagocytosis: Kupffer cells (fixed macrophages) in the liver phagocytize old red blood cells, pathogens, and foreign material.
- Storage: Stores fat-soluble vitamins (A, D, E, and K), water-soluble vitamin B12, and iron, and copper.
- Detoxification: Synthesizes enzymes to detoxify harmful substances like alcohol and medications.

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Test your knowledge on the anatomy of the respiratory system! This quiz covers the structures involved, including the nose, pharynx, larynx, trachea, and lungs. Understand how air is filtered and the roles of various parts in gas exchange.