Name the 5 activities of the GI system
5. Control of function
Know arterial blood supply through mesenteric web
Name the 5 activities of the mouth
Name 2 salivary enzymes
lingual lipase (lipids)
Name the motor functions of the stomach
Name the 2 glands of the stomach
1. gastric glands
2. pyloric glands
What are the secretions of the gastric glands
What are the secretions of the pylorus glands
Between gastric & pylorus glands, name all 5 secretions
HCL, pepsinogen, intrinsic factor, mucus (both), gastrin
Name the 4 types of salivary glands
What are the 3 phases (in order) of gastric secretion
Cephalic phase: vagus nerve prompts pepsin & acid production
Gastric phase: gastrin-histamine stimulation
Intestinal phase: nervous & hormonal mechanisms
What are the 3 segments of the small intestine
What is the primary site of absorption and digestion?
How long is the small intestine?
23 feet long
Bile is secreted by what organ?
Bile is secreted into which part of the digestive system?
What enzymes assist the small intestine in digestion?
Pancreatic digestive enzymes
These secretions come from the brush border of the small intestine
Besides those of the brush border, name the secretion of the small intestine
CCK, secretin, GIP
What secretes CCK?
The I cells of the duodenum and jejunum
What stimulates the secretion of CCK?
Monoglycerides, fatty acids, small peptides and amino acids
Secretion of CCK causes the following 5 reactions
1. contraction of the gall bladder
2. secretion of pancreatic enzymes
3. HCO3 from pancreas
4. inhibition of stomach emptying
5. trophic effects
What secretes secretin?
S cells of the duodenum, in response to H+ and fatty acids
What does secretin stimulate?
Bicarb release from pancreas to increase pH
inhibits gastrin effect on HCL secretion
What secretes GIP?
K cells in the duodenum and jejunum, in response to all types of nutrients (fats, carbs and & proteins)
What is stimulated by GIP?
inhibition of HCL
These 3 pancreatic enzymes help digest proteins
chymotrypsin- proteins to peptides
carboxypeptidase-peptides to amino acids
This pancreatic enzymes helps digest carbs
pancreatic amylase-carbs to di/tri-saccharides
These pancreatic enzymes help digest fats
pancreatic lipase- fat to fatty acids
phospholipase-fatty acids from phospholipids
What are the functions of the liver?
bilirubin and cholesterol
secretion of bile
What prompts the secretion of bile by the liver?
1. meals high in fat
What does bile do?
1. emulsify fats to allow for enzymatic digestion
2. help absorb intestinal mucosa
How does bile absorb intestinal mucosa?
forms micelles, allowing fatty acids to be absorbed by epithelial cells
epithelial cells then break off basolaterally as cholymicrons and enter the lymphatic system then the blood
Bile stored where is 15x more concentrated than bile from the liver
Name 4 causes of gallstones
1. too much water absorbed from bile
2. too much bile acids absorbed from bile
3. too much cholesterol in bile
4. inflammation of epithelium
At rest, bile travels from the liver to...
The gall bladder
During digestion, bile travels from the liver to...
Name the 3 activities of the large intestine
Storage of wastes
Absorption of water & electrolytes
Peristaltic waves which initiate bowel movement
T or F- intestinal epithelium has leaky channels, facilitating H2O movement
Name the 4 main hormones of the GI system
Cholesystokinen, CCK (duodenum)
Glucose-dependent insulinotropic peptide, GIP (duodenum)
Found in the stomach
Stimulated by proteins/amino acids
Aids in gastric acid secretion
Found in duodenum
Stimulated by acidity of sm. intestine
Stimulates pancreatic and liver secretions (via bloodstream)
Found in duodenum
Stimulated by fatty acids and amino acids
Stimulates pancreatic secretions and gall
Inhibits gastric acid secretion
Found in duodenum
Stimulated by glucose, fatty acids
Causes insulin release
Inhibits gastric acid
Name 5 causes of a bowel obstruction
4. Paralytic ileus
Extreme vomiting is cause by a bowel obstruction where?
High up in the GI tract
Acidic vomitus is caused by a bowel obstruction where?
At the pylorus
Extreme constipation with minimal vomiting is caused by a bowel obstruction where?
Low in the GI tract
Name 5 causes of ulcers
1. High acid and peptic content
3. Poor blood supply
4. Poor secretion of mucus
5. Infection, H pylori
Know the progression of fat digestion
Know the progression of protein digestion
What is the equation for Net Filtration Pressure
Glomerular hydrostatic pressure-Bowman's capsule pressure-Glomerular oncotic pressure
What part of the nephron do Loop Diuretics target?
Thick ascending Loop of Henley
They inhibit the sodium-potassium-chloride tri-transporter
Name 3 Loop Diuretics
What part of the nephron do Thiazide diuretics target?
Early distal tubule
Name the 4 steps of glomerular filtration
Aldosterone controls levels of what element?
Where is aldosterone synthesized?
PTH (parathyroid hormone) works on what element?
How does PTH work?
Low Ca++ levels increase circulating PTH. PTH increases Ca++ reabsorption, activates additional Vit D3, and releases Ca++ from bone
How does aldosterone work?
Increases secretion of K+ into the cortical collecting tubules, increasing K+ excretion
Name the only location where the lung is attached to the chest wall
The hilum of each lung is attached, and suspended from, the mediastinum
The pressure of the fluid in the thin space between the lung pleura and the chest wall pleura.
What different pressures cause air to move in & out of the lungs?
1. pleural pressure
2. alveolar pressure
3. transpulmonary pressure
4. compliance of the lungs
These 2 types of forces of the lungs are depicted in a compliance diagram
1. elastic forces of the lung tissue
2. elastic forces caused by surface tension of the fluid that lines the inside walls of the alveoli and other lung air spaces
Surface tension is the interface between alveolar fluid and...
The air in alveoli.
(When filled with fluid instead of air, surface tension does not exist)
Does the diaphragm contract during inspiration or expiration?
Know the amitomical structures
What color are pulmonary arteries?
Is the glottis anterior or posterior to the epiglottis?
Are the larynx & trachea below the glottis or the esophagus?
The alveolus exchanges gas with the...
The pulmonary arteries release .... and accept ....
Still have some O2 left, but releases CO2 and picks up more O2.
Define tidal volume
The volume of air inspired or expired with each normal breath; approx 500 milliliters
Define inspiratory reserve volume
The extra volume of air that can be inspired over and above the normal tidal volume when the person inspires with full force;approx 3000 milliliters.
Define expiratory reserve volume
The maximum extra volume of air that can be expired by forceful expiration after the end of a normal tidal expiration; approx 1100 milliliters.
Define residual volume
The volume of air remaining in the lungs after the most forceful expiration; approx 1200 milliliters.
What are pulmonary capacities
The combination of 2 or more pulmonary volumes
The tidal volume plus the inspiratory reserve volume equals...
Inspiratory capacity (approx 3500 mls)
The expiratory reserve volume plus the residual volume equals...
Functional residual capacity (approx 2300 mls)
Inspiratory reserve volume plus the tidal volume plus the expiratory reserve volume equals...
Vital capacity (approx 4600)
Volumes and capacities are about the same for men and women T or F
F Women have about 20-25% less
What is VT
What is VC
What is Paco2
Partial pressure of carbon dioxide in arterial blood
What is Pao2
Partial pressure of oxygen in alveolar gas
What is Po2
partial pressure of oxygen
What is the average minute respiratory volume?
What is alveolar ventilation
Replenishing new air in the areas of gas exchange (alveoli, alveolar sacs, alveolar ducts, and respiratory bronchioles)
What is dead space?
Areas of respiratory tract that do not exchange gases..nose, pharynx, and trachea. This air never gets in, and this air leaves before newly exchanged gases.
To measure dead space, what would the meter record?
The amount of nitrogen. Oxygen has none, expired air has much.
What is anatomic dead space? And what is its relevance?
Alveoli and they're adjacent gas exchange areas. Relevant bc the healthy person's dead space & atomic dead space should be equal...so atomic dead space reveals alveolar damage.
Dead space plus atomic dead space makes ......dead space
Physiologic dead space
What is the average alveolar ventilation per minute?
Approx 4200 ml/min (given the averages of 500ml tidal vol, 150ml dead space and reps rate of 12)
What is the symbol for alveolar ventilation?
What is the equation for alveolar ventilation?
VA=Freq x (tidal volume-dead space)
What is the symbol for dead space?
Alveolar ventilation is paramount in determining...
Concentrations of O2 and carbon dioxide in the alveoli
Do the bronchioles have cartilage rings for structure like the trachea and bronchi?
No, structure is maintained by transpulmonary pressures
Sympathetic release of these 2 hormones dilate the bronchiole tree, and therefore increase airflow
Epinephrine (especially bc it's beta-adrenergic) and norepinephrine
What hormone do parasympathetic nerves secrete?
Acetylcholine, which causes constriction of the bronchioles
Atropine blocks the effects of what hormone?
Are there any parasympathetic nerves within the lungs?
What else besides acetylcholine can activate parasympathetic nerves to constrict the bronchioles?
Irritants such as smoke, dust, infections, and noxious gases
Where are 'histamine' and 'slow reactive substance of anaphylaxis' made?
In the lungs
What produces histamine and srsa, and when?
Mast cells produce histamine & srsa during an allergic reaction
Cilia line the resp tract, from the nose al the way to the...
What is the carina?
The point where the trachea divides into the bronchi
How fast does the air from a cough travel?
Why can air inspired via an ET cause so many problems within the lungs?
The 3 functions of the nasal cavities are by-passed:
Cold, dry air = crusting and infections of the lungs
Does the pharynx lead to the esophagus or the trachea?
Both, this is the centralized area before bifurcation
How do the particles from cigarette smoke affect the lungs?
Too small to get trapped by resp tract, so they make it to the alveoli. Here 33% precipitate & stay while the rest gets exhaled.
What do the pulmonary vessels supply?
What do the bronchial vessels supply?
The supporting tissues of the lungs
What major characteristic differentiates the bronchial arteries from the pulmonary arteries?
Bronchial arteries carry OXYGENATED blood
Compare the diameter of pulmonary & systemic arteries
Even pulm arterioles are larger than systemic arteries
How and why do the left atrium & ventricle put out a greater percentage of blood than the right atrium & ventricle?
Bronchial blood empties into plum vein & returns directly to left atrium, bypassing right atrium & ventricle
Name the 3 components of pulmonary circulation
1. pulmonary vessels
2. bronchial vessels
How do lymph vessels contribute to pulmonary circulation?
Removal of particulates from alveoli (cleans) as well as removal of plasma protein leaked from capillaries (prevents plum edema).
Lymph vessels within all the supportive tissues of the lungs flow in what direction?
Towards the hilum and dump mostly into the right thoracic lymph duct
What is another term for dead space?
Can residual volume be directly measured?
No, but can be estimated based on age, sex, height, etc.
What is VC?
The volume of air exhaled after a maximal inspiration followed by a maximal expiration. -4600 ml. Vital Capacity
What is TLC?
Maximum volume of air that lungs can contain. (TLC = IRV + Vt + ERV + RV) - 5800 ml. Total Lung Capacity
What is FRC?
Volume of air remaining in lungs at end of normal exhalation (FRC = ERV + RV); increase or decrease possible with lung disease. - 2300 ml. Functional Reserve Capacity
What is IC?
Maximum volume of air that can be inhaled after normal expiration (IC = Vt + IRV). - 3500 ml. Inspiratory Capacity
What is RV?
Air volume in the lungs at the end of maximal expiration, which is the minimum air always present in the respiratory system (dead space)-1200 ml. Residual Volume
What is IRV?
The amount of air that can be inspired forcefully beyond the tidal volume -3000mL. Inspiratory Reserve Volume
What is ERV?
The additional air that can be exhaled after the tidal volume has been exhaled -1100mL. Expiratory Reserve Volume
What are the 2 types of respiratory disorders?
1. Restrictive disorders
2. Obstructive disorders
A pulmonary restrictive disorder is a disease of...
Volume (pulm fibrosis, muscular dystrophy, cysts/lesions)
How does Pulm fibrosis restrict volume?
Stiffening of the lungs and therefore less expansion
how does muscular dystrophy restrict volume?
Diaphragm is less effective
How do cysts/lesions restrict volume?
Crowd the alveoli
A pulmonary obstructive disorder is a disease of...
Flow (asthma, chronic bronchitis, emphysema)
How does asthma restrict flow?
Constriction of airways
How does emphysema restrict flow?
Loss of surface area. The alveoli coalesce. The lungs hyperinflate, but alveoli are ineffective at gas exchange, known as 'Flabby Lung'
Systolic pressure in right ventricle is what percentage of the pressure in the left ventricle?
Why are the pressure of the right ventricle & pulm artery equal during systole, yet pulm artery pressure falls much slower during diastole?
Pulm artery pressure falls slowly because it's blood is flowing through the capillaries of the lungs.
What is the average pulmonary arterial pressure? (the 'average' systemic BP is 120/80)
What is the mean pulmonary capillary pressure?
7 mm Hg
How is pulmonary wedge pressure used clinically?
It is within 2-3 mm Hg of the left atrium. Most feasible way to measure left atrial pressure (and CHF)
How does pulm wedge pressure work?
Cath through peripheral vein into right atrium, right ventricle into plum artery & wedged into a small branch, stopping blood flow. This pressure is 2-3 mm Hg higher than the pulm vessels just beyond it, and they flow into the left ventricle.
What is the blood volume of the lungs?
-450 mls. (70 mls in the capillaries, the rest in the pulm arteries & veins.
A shift in the volume of blood between pulmonary circulation and systemic circulation has a greater effect on which of the 2 systems?
Pulmonary. Systemic has 9x the amount of blood than pulm. So even a mild-moderate shift from systemic can have cause drastic increase in pulm. volume & pressure.
These vessels are (usually) passive, easily changing in diameter to meet the incoming volume
The graph showing the blood pressure gradient within the lungs basically shows what?
The effect of hydrostatic pressure. When standing, the lower part of the lung will have more pressure bc of the weight of the blood above it.
What is Zone 1 of alveolar blood flow?
A pattern of alveolar circulation wherein no blood flows because the local alveolar capillary pressure in that area of the lung never rises higher than the alveolar air pressure during any part of the cardiac cycle
What 2 pressures act upon alveolar capillaries?
1. The BP within the capillaries themselves
2. Compression from air pressure from the host alveoli
What is Zone 2 of alveolar blood flow?
A pattern of alveolar circulation with intermittent blood flow only during the peaks of pulmonary arterial pressure because the systolic pressure is then greater than the alveolar air pressure, but the diastolic pressure is less than the alveolar air pressure
What is Zone 3 of alveolar blood flow?
A pattern of alveolar circulation with continuous blood flow because the alveolar capillary pressure remains greater than alveolar air pressure during the entire cardiac cycle
What pressures ensure that the alveoli stay dry?
The slight - pressure of the pulm capillaries and the pulm lymph system
What are the 2 most common causes of pulmonary edema?
1. left-sided heart failure
2. any toxins, infections, etc. that erode the capillary walls
In humans, what is the normal colloid osmotic pressure in plasma?
What is the normal pulmonary capillary pressure?
Describe the pulmonary edema safety factor
1. pulm capillary pressure is always 1-2mmHg > left atrial pressure
2. normal pulm capillary pressure is 7mmHg
3. normal left atrial pressure is 5-6mmHg
4. plasma colloid osmotic pressure is 28mmHg
So, left atrial pressure can rise to 28mmHg before pulmonary capillary pressure exceeds plasma colloid osmotic pressure, and fluid leaks out of the capillaries causing pulm edema
From the onset of acute pulmonary edema, how before death?
About 30 min
If left atrial pressure is the root of pulmonary edema, how can people with mitral valve disease live without valve replacement?
The lymph vessels adapt by expanding to the chronic excess in fluid. Pressures of 40-45mmHg have been measured in chronic pts.
What is the pleural cavity?
A very thin double membrane between the lungs (pleural membrane) and chest wall (visceral membrane). Just enough fluid within the cavity (a few ml's) to lubricate for lung movement
What is the normal pressure within the pleural cavity?
Anything >-4mmHg will keep the lungs from collapsing.
What is pleural effusion?
Edema within the pleural cavity
What would cause pleural effusion?
1. Blockage of the pleural lymph vessels
2. cardiac failure leading to > pulm capp pressure causing fluid to leak out
3. decreased plasma colloid osmotic pressure causing fluid to leak out
4. infection, toxins or any other inflammation that would erode capillary membranes
A vital concept of diffusion...
How does the concentration gradient affect diffusion?
When there are many on one side and few on the other, there are many more to randomly reach the low side.
In a gas mixture-pressure is directly proportional to what?
What are the 3 main gases for respiration
When discussing blood gases, what besides pressure (& concentration) must be considered?
The solubility coefficient of the gas. That is, it's attraction to water.
Why is the solubility coefficient important?
That determines how many molecules must be present for a certain amount of pressure.
(O2 has lower solubility than carbon dioxide, so much more carbon dioxide can be present & still have a smaller partial pressure)
What is the vapor pressure of water at body temperature?
Most gases of respiration are highly soluble to what?
So, diffusion thru tissue isn't a factor, therefore diffusion of gases thru tissue is almost = diffusion of that gas thru water.
The volume of new atmospheric air in the alveoli with each new breath is....of total alveolar air.
With normal alveolar ventilation, how long does it take to remove 1/2 of the original gas within the alveoli?
About 17 seconds
How is the slow replacement of alveolar air a safety feature?
Prevents sudden, extreme changes in blood gas concentrations, and pH.
What 2 things control alveolar O2 concentrations and partial pressures?
1. Rate of O2 absorption by the blood
2. Rate of new O2 influx by respiration
What is normal PaO2 (partial pressure of alveolar O2)?
What is normal PcO2 (partial pressure of alveolar CO2)?
When measuring the gases of expiration, what would mark alveolar air?
O2 levels at alveolar pressure (104mmHg) and CO2 levels at alveolar pressure (40mmHg)
What parts make up the respiratory unit, or respiratory lobule?
How many alveoli in the 2 lungs?
About 300 million
Does gas exchange take place only in the alveoli?
No gas exchanges in the membranes of all terminal portions of the lungs
Where is surfactant found?
In a layer of the respiratory membrane that is innermost to the alveolus
What is the pressure difference across the respiratory membrane?
The difference between the partial gas in the alveoli and the partial pressure of the gas in the pulmonary capillary blood
What is the average resting diffusion capacity of the resp membrane for O2?
What is the average resting diffusion capacity of the reps membrane for CO2?
Almost equal between pulm blood and alveoli, less than 1mmHg.
What is Va/Q
What is the Va/Q when ventilation is 0, but there is still perfusion?
What is the Va/Q when ventilation is adequate, but there is 0 perfusion?
What is meant by shunted blood?
Venous blood that did not get oxygenated through the pulmonary capillaries due to inadequate ventilation
Is a physiologic shunt when the Va/Q is above or below normal?
Is physiologic dead space considered when the Va/Q is above or below normal?
What is the biggest carrier of carbon dioxide?
What is the main signal for ventialtion rate?
Carotid bodies help to control this as well as BP...
What is the normal FEV (forced expiratory volume)?
Pneumonia is a disorder of....
What is another name for chyme?
Where are parotid glands located and what do they secrete?
Salivary glands at the back of the mouth that secrete a serous fluid rich in amylase which starts carb digestion
What are submandibular glands and what do they secrete?
A serous fluid with some mucus, to thicken and lubricate the bolus. Also has amylase. Makes 70% of saliva
What 2 proteins are found in saliva?
Ptyalin (an a-amylase)-digests starches