Exam 4a Flashcards
What do the mucus neck cells and surface mucuous cells absorb?
Water, ions, short chain FA and some drugs
What is Alveolar Volume? (Va)
Volume of air involved with gas exchange
What is Deglutition?
Process of Swallowing
What enzymes are secreted by the pancreas?
trypsin,
chymotrypsin, pancreatic amylase, lipase,
nucleases
What do mucous cells secrete?
Secrete protective mucus
Describe teniae coli
Portions of the longitudinal muscle in the muscularis externa layerof the large intestine is thickened to form three bands
What is the reverse chloride shift? Why is this important?
1
Define hypoxia.
Oxygen Deficiency
What does diffusing capacity help explain?
Explains how easily a gas can diffuse during external and internal respiration
what are microvilli of the small intestine?
Numerous projections of the plasma membrane of absorptive mucosal cells. Provides further increase in surface area for absorption; digestive enzymes (brushborder enzymes) for some proteins and carbohydrates are housed here.
Describe the pancreas
pale pink lobulated gland located in the C-shaped region of the duodenum.
What are villi of the small intestine?
Finger-like projections of the mucosa
Describe the 3 major mechanisms that regulate blood pH.
- Buffer systems
- Exhalation of CO2
Respiratory system - Kidney excretion of H+
Urinary system
What is the respiratory membrane.
“Sheet” of blood covers the alveoli and membranes of all the terminal portions of the lungs
Describe the Sol Layer (Pericilliary liquid layer (PCL)) of the mucociliary transport system
The lubricant enables the gel mucus present at the tips of the cilia to be transported by the cilia
What is the function of the Submucosal Plexus?
Controlling secretions
List the four factors that result in a difference between the composition of alveolar air and atmospheric air.
- FRC (Functional Residual Capacity) gas is only partially replaced with atmospheric air with each breath
- Oxygen is constantly being absorbed into pulmonary blood
- Carbon dioxide is constantly diffusing from pulmonary blood
- Atmospheric air is humidified before reaching the alveoli
What is the pulmonary edema safety factor?
Left atrial pressure must reach >22.5 mmHg for the rate of pulmonary edema formation to increase linearly with left atrial pressure.
What does parasympathetic stimulation increase in the GI tract?
increases secretion and motility by stimulating ENS
The Pons contains the _______________ and ______________.
Pneumotaxic area and the Apneustic area
Describe the submucosa layer of the GI tract
underlying connective tissue contains numerous blood vessels and nerves
What is SpO2?
1
Define partial pressure.
Each gas in a mixture of gases exerts its own pressure as if all other gases were not present
The pressure of each gas alone is called the Partial Pressure
Why are small bronchioles clinically important as a site of resistance?
- No cartilage
- Abundant smooth muscle
- Contraction will reduce lumen radius
- Small lumen
- Edema and mucus will cause occlusion
What is the structural adaptation of the mucosal wall of the large intestine?
No Villi
Goblet cells
Teniae coli
Why does the sneeze reflex occur?
Nasal irritation
Describe the serosal layer of the GI tract
connective tissue; outermost covering.
When does hemoglobin have the greatest affinity for oxygen?
when 3 of the 4 polypeptide chains are bound to oxygen.
What is the state of perfusion in zone 1?
absent
What does the large intestine absorb?
Remaining salt and water
What is the result of mucus secretion from the mucus neck cells and surface mucuous cells?
Forms a protective barrier that prevents digestion of the stomach wall
When does the rhythum of peristaltic contraction intensify?
as they reach the pylorus which facilitatate passage into the duodenum through the pyloric sphinctor (gastric emptying)
What are some causes of hypoventilation?
- Damage to the CNS
- Peripheral nerve injury
- Damage to pump (muscle paralysis,chest trauma)
- Lung resiting inflation (decreased lung compliance, airway obstruction)
when is the migrating motility complex activated?
During fasting and when most of the food has been absorped
What cause increased blood volume in the lungs?
- heart failure
2. Mitral valve regurgitation
T/F The Bronchioles are innervated by the sympathetic nervous system
False but the B2 receptors will dialate in response to circulating epinephrine and norepineephrine
What is the cause of brown feces?
rusty iron from hemoglobin
What are the extrinsic Glands conected to the oral cavity?
Parotid
Submandibular
Sublingual
What are the functions of Pneumotaxic area
Helps coordinate the transition between inspiration and expiration
Transmits inhibitory impulses to the inspiratory area
Why is the partial pressure of oxygen in venous blood decreased from normal during exercise?
Between 20 and 40 mm Hg, large amounts of O2 are released into the tissues
Contracting skeletal muscle
What does the sublingual gland secrete?
Mucus
List the accessory organs and their functions.
1
What is pulmonary artery vasoconstriction?
Reflex contraction of vascular smooth muscle in the pulmonary circulation in response to low regional partial pressure of oxygen (PO2)
<70% of normal
What does coorpoerative binding mean in terms of hemoglobin?
hemoglobin has a greater ability to bind oxygen after a subunit has already bound oxygen.
How fast do the cilia in the epithelial cells beat?
10-20 x per minute
What is the extrinsic set of nerves in the GI tract?
The Autonomic Nervous System
What happens during an allergic asthmea attack?
Local reflex stimulation due to dust, noxious gas, cigarette smoke, inflammation
Air is a mixture of gases. True or False?
True
What Lungs zones are present in the normal human when standing?
2 and 3
Define cyanosis.
Bluish or red-purple color in the mucous membranes or skin
What is the muscularis layer made up of in the GI tract?
Inner circular layer and outer longitudal layer
What happen to PO2 in the pulmonary capillaries in external respiration.
Increases
What makes up the ENS?
Myenteric Plexus and the Submucosal Plexus
Describe the blood flow in zone 2
Intermittant
Name the subdivisons of the stomach
Cardia
Fundus
Body
Pyloric Antrum
How much higher is hyperbaric chamber pressure raised?
Hyperbaric chamber pressure raised to 3 to 4 atmospheres so that tissues absorb more O2
What happens is duodenum is overfilled?
Gastric motility is inhibited and chyme is transported slower into the duodenum
What can cause alveolar pathology?
Emphysema
What is hyperbaric oxygenation?
Use of INCREASED Pressure to dissolve more O2 in the blood
What is external respiration?
-Pulmonary Gas Exchange
-Exchange of gases between alveoli and pulmonary capillaries
Pulmonary capillaries
Describe the muscularis layer of the GI tract
has two layers of smooth muscle that produces wave-like contractions (peristalsis) to propel food along the GI tract.
What is Vital Capacity? (VC)
Tidal Volume (Vt) + Inspiratory Reserve Volume (IRV) + Expiratory Reserve Volume (ERV)
How does the sneeze reflex occur?
Afferent impulses via trigeminal n. (V) to medulla oblongata
The diffusing capacity for CO2 is ____greater than O2
20 times
What is the percentage of O2 in room air?
21%
What is the Direction of O2 and CO2 diffusion?
Oxygen is going into the RBC and CO2 is going out
What do paneth cells secrete?
Lysozyme
Describe the 2nd stage -Pharyngeal stage of Deglutition
involuntary movement of bolus through the pharynx into the esophagus (esophageal sphincter relaxes before movement into esophagus)
what gas is the most soluble in the blood?
Oxygen?
How do the lungs serve as a blood reservoir?
The lungs serve as a blood reservoir- ½ normal to 2X normal blood volume
Range 225-900 ml
What are brushborder enzymes?
Digestive enzymes that participate in protein and carbohydrate digestion
What is Physiological Dead Space Volume?
Gas in respiratory tract not involved with gas exchange
Vd
What is pleural fluid?
Small volume of fluid between the visceral and parietal layers of the pleura (pleural cavity)
What is the enterogastric reflex?
- Decreases gastric motility
2. Slows the rate of gastric emptying
What does the secretion of pepsinogen do?
Become activated in the form of pepsin which breaks down proteins into peptides
Where is the Sublingual Gland?
Medial to the mandible;
underside of the tongue;
Where does major digestion occur in humans?
Duodenum of the small intestine
What are some causes of hypoxic hypoxia?
high altitude, airway obstruction, or pulmonary edema
Anemic hypoxia
Where are the contractions more in the small intestine?
Duodenum
Describe the two circulation patterns of the lungs.
- High pressure, Decreased blood flow
2. Low pressure, Increased blood flow circulation
what do the bacteria of the large intestine produce?
B complex and vitamin K
What do G Cells Secrete?
Secrete the hormone gastrin
Define dyspnea.
1
What do Chief cells secrete and what is the result?
Secrete pepsinogen and gastric lipase
What is chyme?
mixture of partially digested food and gastric juice is termed
What is the state of perfusion in zone 2?
sporatic
What is the activity of the pyloric sphincter?
Opens to permit passage of chyme into the duodenum
Functions as a valve to prevent backflow and control of how much chyme enters the duodenum
When PO2 increases, SpO2 (% Saturation of Hb) decreases or increases?
Increases
What is the mechanism behind Deglutition?
Muscular contractions of oropharynx and laryngopharynx moves food into the esophagus and ultimately into the stomach
Describe the exchange of O2 and CO2 in the pulmonary capillaries (external respiration).
1
How do you calculate the rate of edema formation?
eduma fluid per hr./dry weight of lung
What is Inspiratory Capacity?
Tidal Volume (Vt) + Inspiratory Reserve Volume (IRV)
What is the basic electrical rhythum of the GI smooth muscle?
slow waves that occur at regular intervals at a relatively constant frequency
Which factors affect O2’s affinity for Hb?
- pH
- PCO2
- Temperature
- . 2,3 Biphosphoglycerate (BPG ) Effect
Where is the myenteric plexus located?
Between the circular and longitudal muscle layers of the muscularis externa (allows for maximum contractrability)
Where are each of the zones in the lung
Zone 3-bottom
Zone 2-middle
Zone 1-bottom
Does PAO2 and PACO2 increase, decrease during hyperventilation?
PaO2 decreases and
PaCO2 increases
What is the function of Migrating Motility Complex?
Housekeeping Function to expel any undigested material into the large intestine to limit bacterial colonization
What connects the myenteric plexus to the submucosal plexus and the myenteric plexus to the motor neuron that connect to the muscularis?
An interneuron
What is the intrinsic set of nerves in the GI tract?
The enteric nervous system
What are the functions of the mucous membranes that cover the conchae?
- Warms the inspired air
- Humidifies the inspired air
- Filters the inspired air
what is mass movement in the large intestine?
similar to peristaltic wave but occurs 3-4 times a day
-propels luminal content toward recturm
Describe the blood flow in zone 1
No blood flow during allportions of the cardic cycle
What is excercised induced pulmonary hemorrhage?
Some horses placed on Lasix to decrease blood volume/pressure, especially pulmonary pressure
What is receptive relaxation response?
Entry of food into the stomach cause the relaxation of the fundus and upper portion of the body in order to accomodate the food with very little pressure
Medulla oblongata contains the ______________.
Medullary rhythmicity area with insptory and expiratory areas
what is the function of the cilia/epithelial cell?
Power stroke towards the pharynx
Is resistance normally high or low?
Low (<1cm H20 gradient from alveoli to atm
What are the functions of the Apneustic area?
Sends impulses to the inspiratory area that activate it and prolong inspiration, inhibiting expiration.
What does the lacteal in the intestinal villus do?
Absorb fat
Why is churning in the stomach important?
Mixes food with gastric juice-allows food to break down
What are the four capacities of the lungs?
Inspiratory Capacity (IC) Vital Capacity(VC) Functional Residual Capacity (FRC) Total Lung Capacity (TLC)
when there is pathology in the alveoli what is compromised?
Gas Exchange, there is more dead space
What cells are found in the small intestine?
Paneth
pH = 7.10PCO2= 60 mm HgHCO3- = 40 mEQ/L
What is the primary problem and Compensatory Response?
1
What happen to PCO2 in the pulmonary capillaries in external respiration.
Decrease
Where does oxygen diffuse from into the blood?
alveoli
The slow waves in the GI smooth muscle work by what?
Slow
Spontaneously
graded depolarization
What do goblet cells in the large intestine produce?
alkaline mucus which lubricates and facilitates the passage of feces
List the different layers of the GI tract.
- Mucosa
- Submucosa
- Muscularis
- Serosa
What is the result of mixing waves provided by the muscularis layer of the stomach?
Macerate food and mix it with gastric juice forming chyme.
What are the structures of the respiratory zone?
Respiratory Bronchioles
Alveolar Ducts
What happen to PO2 in external respiration.
Increases
What happens in the systemic capillaries during internal respiration?
Decrease in PO2
Increase in PCO2
How does the cough reflex occur?
Afferent impulses from vagus n. (X) to medulla oblongata
What is the function of peristalsis in the stomach and what produces it?
The muscularis of the stomach
It functions to force chyme through the pyloric sphncter
How are large (>6um) unwanted particles in the respiratory system trapped-
Sneezed, coughed, and/or swallowed
What is the unique nature of the large intestine?
mass movement-A portion stays contracted for a longer duration before relaxing
what is a unique characteristic of smooth muscle?
Gap junctions-allows muscle to contract as one sheet and enables the transmission of electrical signals between the muscle cells
Describe the three influences on the respiratory center that regulate ventilation.
- Cortical influences
- Chemoreceptor Regulation of respiration
- Proprioceptor Stimulation of Respiration
What is Functional Residual Capacity?
FRC = ERV + RV
Where does gas exchange occur?
At the level of the alveoli
Which structures reabsorb excess fluid in pulmoary edema?
Venous side of capillaries and lymphatic capillaries
What does the external anal sphincter consist of?
Outer ring of skeletal muscle
What are the surface modifications of the small intestine for absorption?
- Circular Folds (plicae circulares)
- Villi
- Microvilli
What are the three steps of respiration.
- Ventilation (Breathing) (inhal and exhale)
- External (Pulmonary) respiration
- Internal (Tissue) respiration
Describe Low pressure, Increased blood flow circulation
Pulmonary artery (PA)- systemic venous blood (decreased oxygen concentration) to lungs
Short– extends only 5 cm beyond apex of right ventricle, Thin wall thickness (1/3 the aorta) Large diameter Large compliance (e.g. 7 ml/mmHg)
Allows pulmonary artery to accommodate the stroke volume from the right ventricle
Efficient gas exchange between pulmonary capillaries and alveoli
Why does the cough reflex occur?
Airway irritation
What is the function of the pyloric sphinctor?
Controls the amount of chyme going into the duodenum
What are the functions of the large intestine?
- Bacteria in the large intestine produce B complex and vit.K.
- Absorption of the remaining salt and water.
- Storage and concentration of undigested food
- Defecation-emptying of the rectum
T/F The bronchiloles are innervated by the parasympathetic nervous system
True-acetylcholine causes constriction
There is also a Local reflex stimulation due to dust, noxious gas, cigarette smoke, inflammation
How are medium (1-5um) unwanted particles in the respiratory system trapped-
Deposited in small bronchiole- Mucociliary transport system
List the components of the respiratory membrane.
- Fluid lining
- Alveolar epithelium
- Basement membrane
- Interstitial space
- Basement membrane
- Capillary endothelium
What is the Heme portion of hemoglobin made of?
The heme portion contains 4 atoms of iron, each capable of combining with a molecule of oxygen
Can you smell CO?
no
Disease produces ______before _______
Disease produces hypoxia before hypercapnia
Describe the exchange of O2 and CO2in the systemic capillaries (internal respiration).
1
Use capillary dynamics to describe how left heart failure causes pulmonary edema.
- Left sided heart failure
- Blood backs up into the pulmonary veins
- Blood Backs up in the pulmonary capillaries
= increase in pulmonary blood volume (pulmonary congestion) - Increased pulmonary hydrostatic capillary pressures and increased pulmonary capillary fluid filtration into the lungs
What is the purpose of the enterogastric reflex?
- allows time for the small intestine to –digest and absorp foodstuff
- regulate the rate at which chyme leaves the stomach
What secretes digestive enzymes and bicarb into the duodenum?
The acini and associated ducts of the pancreas
What does the secretion of gastric lipase do?
Splits triglycerides into fatty acids and monoglycerides
What is the function of HCl in the GI tract?
Kills microbes in food
Denatures proteins
Converts pepsinogen to pepsin
What is air made of?
Nitrogen = 78% Oxygen = 21% FO2 = 0.21 Argon = 0.93% Carbon Dioxide = .04% Other Gases = Neon, Helium, Methane, Krypton, Hydrogen, Water Vapor = .03%
What does this value tell you on the pulse oximeter?
will tell you there is a problem before you can visualize it with mucous membrane color and capillary refill time- CRT
What is Minute Respiratory Volume?
Total amount of new air moved into the respiratory passages each minute
in L/Min or ml/min
MRV = VT (ml) x respiratory rate (RR = breaths per min)
List functions of the liver
- Lipid and protein metabolism
- Glycogenesis
- Detoxification
- Synthesis of bile salts
- Damaged red blood cell removal-bilirubin excretion
What is the function of the Myenteric Plexus?
GI tract Motility
Is there gas exchange in the dead space?
No
What is the unique structural adaptation of the mucosal wall of the stomach
- It has a a mucosal barrier
- bicarbonate rich mucus (protection)
- epithelial cells joined by tight junctions (prevents seepage of gastric juice)
- gastric juices only released when food is present (corrosive)
What is the fractional concentration of O2 in room air.
0.21
what is the function of the paneth cells?
bactericidal function thus regulating microbial population.
Define pulmonary edema.
Excess fluid in the interstitium and alveoli
What does parasympathetic activity promote in GI smooth muscle?
Increased contractability
What is the function of the enzymes in the pancreas?
Digest proteins into smaller polypeptides; polysaccharides into shorter sugars;
and fats into free fatty acids &monoglycerides; nucleic acids into free mononucleotides
Which anal sphincter is involuntary?
Internal
List the causes of pleural effusion.
Blockage of the lymphatics
Heart failure
Reduced plasma colloid osmotic pressure
Infection/inflammation breaking down the capillary membranes
On the Oscillation graph the more ______ = more _______
spikelets, force of contractions
Activity of the muscularis
Mixing waves and peristalsis
What are the parts of the anal sphincter?
Internal and external
How can staying deep under water for too long while scuba diving be a problem?
Explains why you can breathe compressed air while scuba diving despite 79% Nitrogen
- N2 has very low solubility unlike CO2 (soda cans)
- Dive deep and increased pressure forces more N2 to dissolve in the blood (nitrogen narcosis- altered state of awareness)
- Decompression sickness if come back to surface too fast or stay deep too long- nitrogen bubbles in blood and tissues
What is Hyperbaric Oxygenation used for?
Treatment of:
Patients with -
1. anaerobic bacterial infections (tetanus and gangrene)
-Anaerobic bacteria die in the presence of O2
2. Cardiac pathology, CO poisoning, cerebral edema, bone infections, gas embolisms and crush injuries
List the five variables that impact the rate of diffusion through the respiratory membrane- what gas is the most soluble in the blood?
- ∆P – Partial pressure difference
- A – Cross-sectional area of surface
- S – Solubility of gas in the fluid
- X – Distance of diffusion path
- MW- Molecular weight of gas
∆P * A * S D = -------------- X * √MW
What does the Parotid Gland Secrete?
Watery secretion
Is the rate at which alveolar air is renewed by atmospheric air (slow or fast)? Why is this important?
Slow
- Prevents sudden changes in gas concentrations in the blood
- Makes respiratory control mechanism more stable – CNS monitors the arterial blood pH, PO2, and PCO2
- Prevents excessive changes in tissue oxygenation, carbon dioxide concentration, and tissue pH when respiration is temporarily interrupted
Describe the blood flow in zone 3
Continous
Define respiration.
Respiration is the exchange of gases between the atmosphere to alveoli, blood, and tissues/cells.
What shape is the Oxygen hemoglobin disassociation curve and why?
The oxygen-hemoglobin dissociation curve has a sigmoid shape because of the cooperative binding of oxygen to the 4 polypeptide chains.
What are GI smooth muscle influenced by?
Neural activity and hormones
What are smooth muscle cells subject to?
Regulation by the ANS and local environment
What is the function of the intersticial cells of Cajal?
- initiate the basic electrical rhythum
- sets the contractile rhythum
Define affinity.
how tightly O2 binds to hemoglobin
Define Peristalsis
Peristalsis progression of coordinated contractions and relaxations of the esophageal muscle pushes the food down to the stomach
What size particles are exhaled?
< 0.5 µm
What is Total Lung Capacity (TLC)
TLC = IRV + VT + ERV + RV TLC = VC + RV
What is pleural effusion?
Excess Pleural Fluid– Large amount of free fluid in the pleural space
List the three ways and percentages that carbon dioxide is transported in the blood.
70% HCO3- (Bicarbonate ions)
23% Hb-CO2 (Carbaminohemoglobin)
7% Dissolved CO2
If pH = 7.25
PCO2= 30 mm HgHCO3- = 18 mEQ/L
What is the primary problem and Compensatory Response?
1
List the causes of pleural effusion.
Blockage of the lymphatics
Heart failure
Reduced plasma colloid osmotic pressure
Infection/inflammation breaking down the capillary membranes
Describe the 1st stage voluntary stage of Deglutition
bolus moved into oropharynx
What does sympathetic stimulation do to the gI tract?
Sympathetic stimulation decreases secretions and activity by inhibiting ENS
Which anal sphincter is voluntary?
External
What causes decreased blood volume in the lungs?
Playing the trumpet- 250 ml can be expelled from pulmonary into systemic due to increase in pressure
Hemorrhage
What does left shift indicate for O2’s affinity for Hb?
Increased affinity for O2 to bind to hemoglobin
What connects the submucosal plexus to the mucosal epitheliumn?
A Motor Neuron
smooth muscles can contract in ______
unison
What do parietal cells secrete?
Secrete HCl and intrinsic factor(for vit. B12 absorption)
What stimulates the gallbladder and what does that stimulate?
CCK stimulates the release of stored bile into the duodenum during digestion of a meal
Describe the three ways by which pulmonary blood flow increases 4-7 X normal during exercise.
- Increase in pulmonary artery pressures
- Recruitment of closed capillaries which decreases resistance
(Distending capillaries decreases resistance and increases flow) - Zone 2 disappears – the entire lung becomes Zone 3 flow pattern
Mechanical Digestion and _______ works hand in hand
perilastatic motion
What are the steps of the enterogastric reflex?
- Duodenum fills with chyme
- Sensory stretch receptors are stimulated
- Sensory nerve impoulses travel to CNS
- Nerve impulses inhibit peristalsis in stomach wall
What is the normal circulation pattern?
Low pressure, Increased blood flow circulation
Which structures reabsorb excess pleural fluid?
Venous side of capillaries and lymphatic capillaries
What are the accessory organs of the GI tract?
Pancreas
Liver
Gallbladder
What is the most important factor that determines how much oxygen combines with hemoglobin?
PO2
The greater the PO2, the more oxygen will combine with hemoglobin, until the available hemoglobin molecules are saturated
- pH = 7.70PCO2= 60 mm HgHCO3- = 50 mEQ/LWhat is the primary problem and Compensatory Response?
1
Where does major absorption and digestion occur?
Duodenum
Can hb act as a buffer for H+?
Yes, H+ binding alters Hb structure decreasing oxygen carrying capacity
What is the internal anal sphincter consist of?
Inner ring of smooth muscle
Describe the Bohr effect.
- An increase in H+ in blood causes O2 to unload from hb
- The binding of O2 to Hb causes unloading of H+ from Hb
Describe the blood volume of the lungs
450 ml total- 9% of total blood volume (TBV)
70 ml is present in the pulmonary capillaries
380 ml is divided equally among pulmonary arteries and veins
What causes damage to capillary membranes?
infections or breathing toxic gas (e.g. chlorine)
Describe the structure of the conchae.
Conchae or turbinate bones project into the nasal cavity to form ridges that increase the internal surface area and separate the cavity into parallel air passages
Respiratory gases diffuse from areas of _____ partial pressure to areas of _____partial pressure
Respiratory gases diffuse from areas of high partial pressure to areas of low partial pressure
What is hypoxic hypoxia?
Caused by a low PaO2 —> hypoventilation,
Hypoventilation due to airway obstruction or pulmonary edema Low PaO2
When are expiratory neurons activated?
Expiratory neurons inactive during most quiet breathing only active during high ventilation rates
(3 seconds)
Smooth muscle have a ____ _______Structure
Diamond Shaped
pH = 7.60
PCO2= 20 mm HgHCO3- = 15 mEQ/L
What is the primary problem and Compensatory Response?
1
What is Alveolar PO2?
Balance between: oxygen absorbed by blood and new oxygen breathed in
What does the endocrine portion of the pancreas have?
pancreatic islets-
What are the structures of the conducting zone?
Trachea
Bronchi
Nonrespiratory Bronchioles
- In 100 ml of oxygenated blood, how is O2 transported?
- 5% of the O2 is dissolved in the plasma
98. 5% is carried with hemoglobin (Hb) inside red blood cells as oxyhemoglobin (HbO2)
What is the function of motility in the GI tract?
- Allows bidirectional propulsion of chyme (results in increased contact time of digestive products with gastric mucosa)
- causes chyme to move along the length of small intestine
How is the partial pressure of a gas calculated (equation)?
Calculated by Multiplying its Fractional Concentration by the Total Pressure Exerted by All Gases.
Px = Fx X Pt
Px = Partial pressure of gas Fx = percentage of gas in room air (also called fractional concentration of gas) Pt = atmospheric pressure (total pressure)
What are the anatomical components that contribute to dead space?
Nose Pharynx Larynx Trachea Bronchi
What is Alveolar Ventilation?
Total volume of new air entering the alveoli and adjacent gas exchange areas each minute
VA = VA X RR
What is produced by the pancreatic islets in the endocrine portion of the pancreas?
insulin and glucagon;
What are the plicae circulares?
Permanent transverse ridges of mucosa
When PaO2 is Hb almost fully saturated?
60 mmhg
What is the state of perfusion in zone 3?
constant
Define Lung Capacity
Two or More Lung Volumes
What gas has the highest percentage in room air?
Nitrogen
What does pulmary edema do in terms of diffusion?
Increases diffusion distance
Describe the structure/function of the mucus gel blanket
Goblet cells and submucosal glands
Nose to respiratory bronchioles
Moistens epithelial cells and traps particles
How are small (< 1um) unwanted particles in the respiratory system trapped-
Stick on alveolar wall- Alveolar Macrophages
Describe the High pressure, Decreased blood flow circulation?
Branches of thoracic aorta supplies systemic arterial blood (normal oxygen concentration) to:
- Trachea, large/small bronchi, supporting tissues of the lungs- connective tissue and septa
- Bronchial arteries supply most of this arterial blood
Where is the respiratory center in the brain?
Brainstem
How is CO poisoning treated?
Treat by administering 100% O2
What part of the pancreas is the acini and associated ducts located?
exocrine portion
Describe the neural innervations of the GI tract
- Enteric Nervous System (“Brain of the Gut”)
2. Autonomic Nervous System
What is the function of pleural fluid?
Provides lubrication and reduces friction during breathing
Describe the esophageal stage (3rd) of Deglutition
Involuntary passage of food through the esophagus via peristaltic waves into the stomach
Why Does pulmonary artery vasoconstriction occur?
This vasoconstriction by the pulmonary vasculature represents its fundamental difference from the systemic circulation, which typically vasodilates in response to hypoxia
5X increase in vascular resistance reduces blood flow through areas of lung where PO2 is low. Blood is distributed where needed in different regions of the lungs
What happens when the bronchioles are stimulated by something irritating such as dust?
Mast cells degranulate an an allergic reaction happens
What are the functions of the Medullary rhythmicity area?
Control the basic rhythm of respiration
What does the Submandibular Gland Secrete?
Mixed Serous and Mucus
What does intrinsic factor do in the GI tract?
Needed for the absorbtion of vitamin B12 which is used in RBC formation
What is hemoglobin?
Hemoglobin consists of a protein portion called globin and a pigment called heme.
What are haustra and what causes them?
Tonic contractions causes the teniae coli to form pocket-like pouches in the wall of the colon called haustra.
Describe the mucosa layer of the GI tract
epithelium that lines the lumen of the GI tract
What regulates gastric emptying?
Hormonal/neuronal reflexes
Where is the parotid gland?
Parotid-between the base of the ear and mandibular gland
What is the mechanism of a cough?
Response – large inspiration, closed glottis, abdominal wall muscle contractions, sudden opening of glottis, massive rush of air out of the lungs (100 mph)
Where is the least amount of resistance to airflow encountered?
Least resistance is in the smaller lower airways
due to the increased number of branches that increases total cross sectional area
What are the functions of the salivary glands?
Lubrication and thermoregulation -(Dogs)
salivary amylase-starch breakdown
What are the pacemaker cells of the GI smooth muscle?
Intersticial Cells of Cajal
What is stomach emptying inhibited by?
enterogastric reflex
enterogastrones
fat in the duodenum
Where is smooth muscle found?
In Organs that are automatic in function
How are expiratory neurons activated?
1
What do goblet cells secrete?
Mucus
What are the timed volumes in the respiratory system?
Minute Respiratory Volume and Alveolar Ventilation
Where is most of the resistance to airflow encountered?
Most resistance is in the larger upper airways (trachea and bronchi)
What is the unique structural component of the Anus?
Anal sphincter that regulates the passage of feces outside the body
How long does it take the chyme to reach the large intestine?
2 hrs
What is the end of the digestive tract?
Anal Canal
What are the stages of Deglutition?
- Voluntary
- Pharyngeal
- Esophageal
What does the duodenum receive?
pancreatic secretions and bile from the liver or gall bladder
Where does chyme exit the stomach?
pyloric sphincter (Gatekeeper) into the small intestine
Respiratory gases _________from areas of _________ partial pressure to areas of _________ partial pressure.
Respiratory gases diffuse from areas of high partial pressure to areas of low partial pressure
The higher the partial pressure of a gas, the higher or lower gas concentration?
It is Directly proportional so if the concentration increases so does the partial pressure
the slow waves in the GI smooth muscle must do what to reach an action potential?
reach a threshhold
Partial Pressure of a Gas in solution is determined not only by its ___________, but also its _______________.
Partial Pressure of a Gas in solution is determined not only by its Concentration, but also its Solubility Coefficient.
Px = Cx / ßx
What zone is present in a pathological lung?
1
what is internal respiration?
-Systemic Tissue Gas Exchange
The Exchange of gases between systemic tissue capillaries and tissue/cells
What is larger, a RBC or a Capillary?
RBC (7.5 Micrometers)
What is FRC?
Functional Residual Capacity
FRC = The rate at which alveolar air is renewed by atmospheric air
Where is the Submandibular Gland?
caudal to the angle of the jaw
What happens when cows graze in high altitude?
Right heart failure
What does membrane bound enteropeptidase kickstart?
Trypsinogen coversion to its active form trypsin
What are segmental contractions?
churning
Ring like contrictions
What connects the Myenteric Plexus to the Muscularis?
Motor neurons that control motility
What comes together at the same time to activate protein digesting enzymes in the small intestine?
Enteric nervous system with local stimuli when food is available
What does gastrin do in the GI tract after secretion from the G cells?
Stimulate the pareital cells to secrete HCl and chief cells to secrete pepsinogen
Contraction of the esophageal sphinctor occurs and motility of the stomach occurs. The pyloric sphingtor relaxes as well.
What part of the stomach is adjacent to the body?
Fundus
Name the secretory cells of the GI tract and list their secretions.
Parietal cells
Chief Cells
Mucous Cells
G Cells
What does the liver consist of?
Bile pigments (waste products) Bile Salts (emulsification of fats)
Explain why carbon monoxide poisoning decreases the oxygen content of blood.
CO binds to Hb heme group 250X more successfully than O2
What type of fluid is pleural fluid?
Interstitial fluid that transudes from the pleural membranes
What lung zones are normally present in a human in supine postion ?
3
