Lecture Exam 3
Which structures are parts of the conducting portion of the respiratory system?
Nose, nasal cavity, nasal sinuses, pharynx, larynx, trachea, bronchi/bronchioles to terminal branches
What are functions of respiratory system?
The primary function of the respiratory system is to exchange gases. Oxygen is inhaled so the blood can carry it to the parts of the body and carbon dioxide, a waste product is breathed out.
Which part of lung is covered by the parietal pleura and visceral pleura?
Parietal pleura covers inner surface of thoracic wall.
Visceral pleura covers out surface of lungs
What are the superior and inferior borders of the pharynx?
Connects the nasal cavity and mouth superiorly to larynx and esophagus inferiorly.
How does the epiglottis prevent aspiration of foods and liquids?
Epiglottis is elastic cartilage that covers the laryngeal inlet during swallowing. During swallowing the larynx is pulled superiorly and the epiglottis tips to cover the laryngeal inlet
List nine pieces of cartilages in larynx.
Three are single: thyroid cartilage, epiglottis and cricoid cartilage. The remaining cartilages are paired and include: Arytenoid, cuneiform and Corniculate.
List three subdivisions of the pharynx.
Nasopharynx, oropharynx and laryngopharynx
What is the main function of the vocal folds?
Vibrate, producing sounds as air rushes up from the lungs.
What is the benefit of not having cartilage between the trachea and esophagus?
Because it is flexible, the esophagus can expand anteriorly as swallowed food passes through it.
How many lobes and secondary bronchi are present in each lung?
3 lobes and 3 secondary bronchi in right lung. 2 lobes and 2 secondary bronchi in left lung
What type of membrane is the pleural membrane?
A thin, double-layered serosa. (A serous membrane)
Why are the right and left lungs slightly different in size and shape?
The two lungs differ slightly in shape and size because the apex of the heart is slightly to the left of the median plane.
What types of cells make up the wall of an alveolus?
The walls of the alveoli are composed primarily of a single layer of squamous epithelial cells called type I alveolar cells. Scattered amid those cells are cuboidal type II alveolar cells.
How thick is the respiratory membrane?
The respiratory membrane is only between 0.5-1.0 micrometers thick making gas exchange very efficient. The thinness is hard to imagine, but a sheet of tissue paper is 15 times thicker.
Right now, what is the main muscle that powers your breathing?
What is normal atmospheric pressure at sea level?
Tidal volume (TV)
Amount of air inhaled or exhaled with each breath under resting conditions.
Adult male and female average value: 500ml
Inspiratory reserve volume (IRV)
Amount of air that can be forcefully inhaled after a normal tidal volume.
adult male avg: 3100ml; adult female avg: 1900 ml
Residual volume (RV)
Amount of air remaining in the lungs after a forced expiration.
adult male avg: 1200 ml; adult female avg: 1100 ml
Total lung capacity (TLC)
Maximum amount of air contained in lungs after a maximum inspiratory effort: TLC = TV + IRV + ERV + RV
Vital capacity (VC)
Maximum amount of air that can be expired after a maximum inspiratory effort: VC = TV + IRV + ERV
Inspiratory capacity (IC)
Maximum amount of air that can be inspired after a normal tidal volume expiration: IC = TV + IRV
Functional residual capacity (FRC)
Volume of air remaining in the lungs after a normal tidal volume expiration: FRC = ERV + RV
If you breathe in as deeply as possible and then exhale as much air as you can, which lung capacity have you demonstrated?
Expiratory reserve volume
What causes oxygen to enter pulmonary capillaries from alveoli and to enter tissue cells from systemic capillaries?
Simple diffusion. According to a concentration gradient. Oxygen and Co2 both diffuse down a concentration gradient (high to low)
What is defecation and how does it occur?
Defecation is elimination of the contents of the bowels (feces). This occurs when stretching of rectum wall initiate the defecation reflex. This parasympathetic reflex causes the sigmoid colon and rectum to contract and the internal anal sphincter to relax. As feces are forced into anal canal, messages reach the brain allowing us to decide whether external (voluntary) anal sphincter should open or remain constricted.
What are haustra?
Pocket like sacs caused by the tone of the teniae coli.
What is the fuction of the goblet cells in the large intestine?
Mucus produced by goblet cells eases the passage of feces and protects the intestinal wall from irritating acid and gases released by resident bacteria.
Which portions of the colon are retroperitoneal?
The colon is retroperitoneal, except for its transverse and sigmoid parts.
What type of tissue is the main component of teeth?
Is swallowing a voluntary action or involuntary action?
Both. The buccal phase that occurs in the mouth is voluntary. The pharyngeal-esophageal phase is involuntary and is controlled by the swallowing center located in the brain stem.
In which layers of the esophagus are the glands that secrete lubricating mucus located?
The submucosa contains mucus-secreting esophageal glands.
After a very large meal, does your stomach still have rugae?
No, after a large meal the rugae stretch and disappear as the stomach fills.
Which structures of the digestive system secrete digestive enzymes?
Salivary glands, tongue, stomach, pancreas and small intestine
By which routes do absorbed nutrients reach the liver?
Via the hepatic portal system.
Which two organs of the digestive system secrete the most fluid?
The stomach and pancreas
What is the function of the fluid secreted by duodenal (Brunner's) glands?
Brunner's glands in the duodenum secrete alkaline mucus that helps neutralize acidic chyme moving from the stomach.
What is the function of the Uvula?
The fleshy mass of tissue that hangs from the posterior of the soft palate, moves upward when swallowing to close off nasopharynx, preventing food from entering the nasal cavity. Also helps to fight infection.
Where is gastrin secreted and what is its function?
Produced by G cells of the stomach mucosa, it plays essential roles in regulating stomach secretion and motility.
* Increase HCl secretion
*Stimulates gastric emptying
*Stimulates contraction of intestinal muscle
*Relaxes ileocecal valve
*Stimulates mass movements
What portion of the small intestine is the longest?
Cranial Nerves for digestion
*Smell (I) Olfactory
*See (II) Optic
*Chew (V) Trigeminal
*Taste, salivation, facial expression (VII) Facial
*Taste, swallow, salivation (IX) Glossopharyngeal
*Swallow, smooth muscle contraction, slow heart rate, secretion by digestive gland (X) Vagus
*Swallowing, muscle of pharynx, larynx, soft palate (XI) Accessory
*Tongue muscles (XII) Hypoglossal
Period of breathing when air enters the lungs.
Exchange of gases between the systemic capillary blood and body cells.
Alternate flushing of air into and out of the lungs
Exchange of gases between alveolar air and pulmonary capillary blood.
Period of breathing when air leaves the lungs
Respiratory volume inhaled or exhaled during normal breathing
Dead space volume
Air in respiratory passages that does not contribute to gas exchange
Vital Capacity (VC)
Total amount of exchangeable air
Residual Volume (RV)
Gas volume that allows gas exchange to go on continuously
Expiratory reserve volume (ERV)
Amount of air that can still be exhaled (forcibly) after a normal exhalation
*The diaphragm and external intercostal muscles contract and the rib cage rises
*The lungs are stretched and intrapulmonary volume increases
* Intrapulmonary pressure drops below atmospheric pressure (-1mmHg)
*Air flows into the lungs, down is pressure gradient, until intrapleural pressure = atmospheric pressure
*Inspiratory muscles relax and the rib cage descends due to gravity
*Thoracic cavity volume decreases
*Elastic lungs recoil passively and intrapulmonary volume decreases
*Intrapulmonary pressure rises above atmospheric pressure
*Gases flow out of the lungs down the pressure gradient until intrapulmonary pressure is 0