Lecture Exam One Flashcards
define external respiration
movement of oxygen from the lungs to the blood and of carbon dioxide from the blood to the lungs
define internal respiration
movement of oxygen from the blood to the tissue cells and of carbon dioxide from tissue cells to blood
define cellular respiration
the actual use of oxygen and production of carbon dioxide by tissue cells
list four functions of the respiratory mucosa
moistens air, warms air, cilia filter air, enzyme lysozyme destroys bacteria
list three divisions of the pharynx
nasopharynx, oropharynx, and laryngopharynx
which division of the pharynx do the eustachian tubes drain into?
the eustachian tubes drain into the lateral walls of the nasopharynx
which division of the pharynx assists in swallowing
the laryngopharynx assists in swallowing
where do the respiratory and digestive systems become distinct
in the laryngopharynx the respiratory and digestive pathways diverge and the larynogophraynx is continuous with the esophagus posteriorly
define and describe the larynx
larynx is also known as voice box. attaches to the hyoid bone and opens into the laryngopharynx. Inferiorly it is continuous with trachea.
what are the functions of the larynx
- to provide a patent (open) airway 2. to act as a switching mechanism to route air and food into the proper channels. 3. voice production
describe the structure of the vocal chords
are under the laryngeal mucosa on each side. attach the arytenoid cartilages to the thyroid cartilage. composed largely of elastic fibers, form the core of mucosal folds called true vocal chords. Appear pearly white because they lack blood vessels. function is voice production
describe the structure of the glottis
it is the vocal folds (chords) and the medial opening that goes between them.
describe the structure of the epiglottis
composed of elastic cartilage and is almost entirely covered in taste bud-containing mucosa. is flexible and spoon shaped. extends from the posterior aspect of the tongue to its anchoring point on the anterior rim of the thyroid cartilage
discuss the trachea
descends from the larynx through the neck and into the mediastinum. it ends by dividing the two main bronchi at mid thorax. trachea wall consists of several layers that are common to many tubular body organs–the mucosa, submucosa, and adventitia–plus a layer of hyaline cartilage.
discuss the mucosa layer of the trachea
the mucosa has the same goblet cell containing psuedostratified epithelium that occurs throughout most of the respiratory tract. its cilia continually propel debris-ladden mucus toward the pharynx.
discuss the submucosa layer of the trachea
the submucosa layer of the trachea is a connective tissue layer deep to the mucosa that contains seromucous glands that help produce the mucus “sheets” within the trachea. The submucosa is supported by 16-0 c shaped rings of hyaline catilage encased by the adventitia, the outermost layer of connective tissue.
trachea continued
the trachea’s elastic elements make it flexible enough to stretch and move inferiorly during inspiration and recoil during expiration, but the cartilage rings prevent it from collapsing and keep the airway patent (open) despite the pressure changes that occur during breathing. The open posterior parts of the cartilage rings, which abut the esophagus, are connected by smooth muscle fibers of the trachealis muscle and by soft connective tissue.
define carina
the carina is the last trachea cartilage. it is expanded and projects posteriorly from its inner face, marking the point where the trachea branches into the two main bronchi. The mucosa of the carina is highly sensitive and violent coughing is triggered when a foreign object makes contact with it.
define the bronchial or respiratory tree
the branching pattern of the airwaves. the site where conducting zone structures give way to respiratory zone structures.
describe bronchi
the trachea divides to form the righ and left main (primary) bronchi approximately at the level of T7 in an erect person. Each bronchus runs obliquely in the mediastinum before plunging into the medial depression of the lung on its own side. The right main bronchus is wider, shorter, and more vertical than the left. Therefore, it is the more common site for an inhaled foreign object to become lodged.
once inside the lungs, each main bronchi subdivides into lobar (secondary) bronchi–three on the right and two on the left–each supplying one lung lobe.
the lobar bronchi branch into third-order segmental (tertiary) bronchi, which divide repeatedly into smaller and smaller bronchi.
describe bronchioles
passages smaller than 1 mm in diameter are called bronchioles, and the tiniest of these, the terminal bronchioles are less than 0.5 mm in diameter.
more about bronchi and bronchioles
the tissues of the walls of the main bronchi mimics that of the trachea, but as the conducting tubes become smaller, the following structural changes occure:
- the cartilage rings are replaced by irregular plates of cartilage, and by the time teh bronchioles are reached, supportive cartilage is no longer present in the tube walls. However, elastic fibers are found in the tube walls throughout the bronchial tree.
- the mucosal epithelium thins as it changes from pseudostratified columnar to columnar and then to cuboidal in the terminal bronchioles. Cilia are sparse, and mucus-producing cells are absent in the bronchioles.
- the relative amount of smooth muscle in the tube walls increases as the pasageways become smaller. A complete layer of circular smooth muscle in the bronchioles and the lack of supporting cartilage allows the bronchioles to provide substantial resistance to air pasage under certain conditions.
function and structure of conducting zone of the lungs
the conducting zone of the lungs is made up of the trachea, windpipe, which branches off into the main (primary) bronchi. The bronchi further subdivides into the lobar bronchi which splits further into segmental (tertiary) bronchi. These tertiary divide repeatedly into smaller and smaller bronchi until they are small enough to be called bronchioles…(if smaller than 1 mm in diameter)
The purpose of the trachea as an air passageway is to clean, warm, and moisten incoming air.
the bronchial tree is also an airpasage connecting the trachea with alevoli; cleans warms, and moistens incoming air.
function and structure of the respiratory zone of the lungs
the respiratory zone begins as the terminal bronchioles feed into respiratory bronchioles within the lung. Present are thin-walled air sacs called alveoli. These air sacs are where gas exchange occurs.
the respiratory bronchioles have scattered alveoli in their walls which lead into alveolar ducts, which are completely lined by alveoli. These ducts end in clusters of alveoli called alveolar sacs. The alveolar sacs look much like a bunch of grapes with the alveoli being a single grape.
gas exchange occurs in the alveoli across the respiratory membrane. this occurs through simple diffusion—O2 passes from the alveolus into the blood, and CO2 leaves the blood to enter the gas-filled alveolus.
list and define the three types of cells present in the alveoli
- the walls of the alveoli are composed primarily of a single layer of squamous epithelial cells, called type 1 cells, surrounded by a flimsy basement membrane.
The external surfaces of the alveoli are densely covered with a “cobweb” of pulmonary capillaries. Together the alveolar and capillary walls and their fused basement membranes form the respiratory membrane.
- cuboidal type 2 cells are spread amongst the type 1. These cells secrete a fluid containing a detergent-like substance called surfactant that coats the gas exposed alveolar surfaces.
- the alveoli also contain aleolar macrophages that crawls freely along the internal surfaces.
define parietal pleura
the parietal pleura covers the thoracic wall and superior face of the diaphragm. It continues around the heart and between the lungs, forming the lateral walls of the mediastinal enclosure and snugly enclosing the lung root.
define visceral pleura
the layer of the pleura that covers the external lung surface, dipping into and linning its fissures.
define pleural cavity
the slit-like cavity between the parietal and visceral pleurae.
this cavity is filled with pleural fluid and the lubricating secretion allows the lungs to glide easily over the thorax wall during breathing movements.
the pleura also help divide the thoracic cavity into three chambers–the central medistinum and the two lateral pleural compartments, each containing a lung.
define pleurisy
inflammation of the pleurae, often results from pneumonia. Inflamed pleurae become rough, resulting in friction and stabbing pain with each breath.
disease progression involves an excessive amount of liquid production. the increased fluid relieves pain caused from the pleural surfaces rubbing together, but may exert pressure on the lungs and hinder breathing movements.
define pleural effusion
fluid accumulation in the pleural cavity
define Boyles law
describes the relationship between the volume and pressure of gases. It says that at constant temperature, the pressure of a gas varies inversely with its volume.
volume changes lead to pressure changes, and pressure changes lead to the flow of gases to equalize the pressure.
for example: in a large container, the molecules in a given amount of gas will be far apart and the pressure will be low. But if the volume of the container is reduced, the gas molecules will be forced closer together and the pressure will rise.
which muscles are involved in breathing? and which one is most important?
the diaphragm and intercostal muscles
the most important is the diaphragm
name the nerve that controls the diaphragm
the phrenic nerve controls the diaphragm
define the term compliance as it relates to the respiratory system
lung compliance is a measure of the change in lung volume that occurs with a given change in the transpulmonary pressure.
the more a lung expands for a given rise in transpulmonary pressure, the greater its compliance.
or the higher the lung compliance, the easier it is to expand the lungs at any given transpulmonary pressure
lung compliance is determined largely by two factors:
- distensibility of the lung tissue
- alveolar surface tension
because lung distensibility is generally high and alveolar surface tension is kept low by surfactant, the lungs of healthy people tend to have high compliance
lung compliance is diminished by a decrease in the natural resilience of the lungs. Chronic inflammation, or infections such as tuberculosis, can cause nonelastic scar tissue to replace normal lung tissue (fibrosis)
define tidal volume
tidal volume is the amount of air that moves into and then out of the lungs during normal quite breathing–500 ml
define inspiratory reserve volume
inspiratory reserve volume is the amount of air that can be inspired (breathed in) forcibly beyond the tidal volume (2100-3200 ml)
define expiratory reserve volume
expiratory volume is the amount of air–normally 1000 to 1200 ml—that can be evacuated from the lungs after a tidal expiration.
define resdiual volume
residual volume is the amount of air that remains in the lungs even after the most strenuous expiration, about 1200 ml. This helps to keep the alveoli patent and to prevent lung collapse
define inspiratory capacity
inspiratory capacity is the total amount of air that can be inspired after a tidal expiration…it is the sum of tidal volume and inspiratory reserve volume
define functional residual capacity
functional residual capacity is the amount of air remaining in the lungs after a tidal expiration and is the combined residual volume and expiratory reserve volume
define vital capacity
vital capacity is the total amount of exchangeable air. it is the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume.
define total lung capacity
total lung capacity is the sum of all lung volumes and is normally around 6000 ml
define anatomical dead space
inspired air that fills the conducting respiratory passageways and never contributes to gas exchange in the alveoli.
define minute respiratory volume
total amount of gas that flows into or out of the respiratory tract in 1 minute. During normal quite breathing, the minute ventilation in healthy people is about 6 L/min
define Dalton’s law
Dalton’s law of partial pressures states that the total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture
also, the pressure exerted by each gas–the partial pressure, is directly proportional to the percentage of gas in the gas mixture
list the three factors that determine the solubility of gases
the solubility of gases is influenced by these three factors:
- temperature - increasing the liquids temperature decreases the gas’ solubiity.
- partial pressure - the partial pressure of the gas compared to the partial pressure of the liquid
- the nature of a solvent and solute - whether the solute and solvent is polar or non-polar
define Henry’s law
says that gas will dissolve in a liquid in proportion to its partial pressure. therefore, the greater the concentration of a particular gas in the gas phase, the more and the faster that gas will go into solutin in the liquid.
at equilibrium, the gas partial pressures in the two phases are the same. If, however, the partial pressure of the gas later becomes greater in the liquid than in the adjacent gas phase, some of the dissolved gas molecules will reenter the gaseous phase. So the direction and amount of movement of a gas is determined by its partial pressure in the two phases.
Carbon dioxide is very soluble in blood, allowing many molecules to diffuse along this small partial pressure gradient.
oxygen is less soluble, requiring a larger concentration gradient.
list four factors that determine the rate of exchange of oxygen and carbon dioxide across the alveolar-capillary membrane (respiratory membrane)
- thickness of the membrane - any factor that increases respiratory membrane thickness will interfere with normal respiratory exchange of gases
in edema - increased fluid in the interstitial space - because gas must diffuse through the fluid
fibrosis - an increase in respiratory membrane thickness
- surface area of the membrane - the greater the surface area of the respiratory membrane, the more gas can diffuse across it in a given time period.
in certain pulmonary diseases, the alveolar surface area actually functioning in gas exchange is drastically reduced. This occurs in emphysema, when the walls of adjacent alveoli break down and the alveolar chambers become larger.
- the solubility of the gas - carbon dioxide is much more soluble than oxygen
- partial pressure gradients - there is a steep partial pressure gradient across the respiratory membrane because the partial pressure of O2 of the deoxygenated blood in the pulmonary arteries is only 40 mm Hg, as opposed to a Po2 of approximately 104 mm Hg in the alveoli. This means O2 diffuses rapidly from the alveoli into the pulmonary capillary blood. Equilibrium–that is a Po2 of 104 mm Hg on both sides of the respiratory membrane—usually occurs in .25 second, about 1/3 the time a RBC is in a pumonary capillary
explain the method by which oxygen and carbon dioxide are carried by the blood
oxygen is carried in the blood by two ways:
- bound to hemoglobin within red blood cells
- dissolved in plasma
explain why carbon monoxide is so dangerous
carbon monoxide is dangerous because it competes with oxygen and wins. it is also an odorless and colorless gas that is hard to detect
how does carbon monoxide interact with hemoglobin
What is formed when carbon monoxide and Hb bind
carbon monoxide binds with the heme sites on hemoglobin which has an affinity for CO more than 200 times the affinity for oxygen
when Hb and CO bond carboxyhemoglobin is formed
what are the three parts of the respiratory center of the brainstem
Dorsal respiratory group
ventral respiratory group
pontine respiratory centers
where are the respiratory centers located?
they are located in the pons (pontine centers)
and the medulla oblongata
explain what happens if the carbon dioxide concentration in the blood rises above normal.
if the carbon dioxide concentration in the blood rises above normal, called hypercapnia, CO2 accumulates in the brain. As it accumulates it forms carbonic acid. The acid dissociates, H+ is liberated, and the pH drops.
The increase in H+ excites the central chemoreceptors, which make abundant synapses with the respiratory regulatory centers. As a result, the depth and rate of breathing are increased. This enhanced breathing (aveolar ventilation) quickly flushes CO2 out of the blood, increasing blood pH.
define hypercapnia
high carbon dioxide levels in blood
which receptors sense the increase of carbon dioxide in the blood?
the central chemoreceptors
list two factors affected by exercise which results in an increase in the depth and rate of breathing
working muscles consume large amounts of O2
and produce large amounts of CO2
so ventilation increases
which “other activity” of the respiratory system persists even during deep coma?
coughing
explain the stages of development of the respiratory tree at :
week 4: trechea and bronchial buds appear around 4 weeks
week 8: bronchi are in mature form about 8 weeks
then broncholies branch
by week 24 alveoli form and surfactant is secreted
list the 8 major functions of blood
- transport respiratory gases
- helps regulate acid-base balance
- aids in the transport of nutrients, hormones, and enzymes
- helps transport wastes
- regulates body temperature
- aides in stoppage of bleeding
- helps regulate body fluids
- helps defend against microorganisms and toxins
explain how blood gets its red color
the amount of oxygen determines the red color.
oxygen rich blood is scarlet
oxygen poor blood is deep red
define blood viscosity
the measure of the thickness of blood. having a higher number of RBS accounts for a higher viscosity.
higher viscosity translates to slower blood flow
define blood
specialized connective tissue, in which living blood cells, called the formed elements, are suspended in a nonliving fluid matrix called plasma.
how much of blood is “formed elements”
what are they?
about 45% of blood is the formed elements
they are a buffy coat - consisting of leukocytes and platelets <1% of whole blood
and erythrocytes which are 45% of whole blood, most dense component
how much of blood is plasma?
plasma makes up 55% of blood
list the components of plasma and what each does
water - 90% of plasma volume; dissolving and suspending medium for solutes of blood; absorbs heat
plasma proteins:
Albumin - 60% of plasma proteins; produced by liver; main contributor to osmotic pressure
Globulins - 36% of plasma proteins - alpha, beta–produced by liver; most are transport proteins that bind to lipids, metal ions, and fat-soluble vitamins
gamma- antibodies released by plasma cells during immune response
fibrinogen - 4% of plasma proteins; produced by liver; forms fibrin threads of blood clot
nonprotein nitrogenous substances—-by products of cellular metabolism, such as urea, uric acid, creatinine, and ammonium salts
describe the general structure and chemical make up of an erythrocyte (RBC)
small cells; shaped like biconcave disks—flattened discs with depressed centers—they appear lighter in color at their thin centers than at their edeges…mature erythrocytes are bound by a plasma membrane, but lack a nucleus
they are basically bags of hemoglobin, the RBC protein that functions in gas transport
what is the benefit of the RBCs shape?
the biconcave shape of RBCs, erythrocytes, is to increase surface area.
describe the components of hemoglobin
hemoglobin is made up of the protein globin bound to the red heme pigment (heme contains iron)
a hemoglobin molecule can transport four molecules of oxygen because each iron atom can combine reversibly with one molecule of oxygen
list three properties of the cell membrane of the RBC
