231 Physiology Term 2 Learning Objective 3 & 4 plus 3 diseases Flashcards
What are the functions of the respiratory system?
- Main function is gas exchange
- Also plays an important role in pH balance
- Sound production
What are the four processes of respiration?
- Pulmonary ventilation (breathing)
- External respiration
- Transport of respiratory gases
- Internal respiration
Describe the pulmonary ventilation process.
- Ventilation consists of inspiration and expiration
- Inspiration moves air into the lungs from the atmosphere
- Expiration moves air out of the lungs into the atmosphere.
Describe the external respiration process.
- oxygen diffuses from the lungs to the blood
- carbon dioxide diffuses from the blood into the lungs
Describe the transport of gases process.
- the cardiovascular system transports gases using blood as the transporting fluid
- oxygen is transported from the lungs to the tissue cells of the body
- carbon dioxide is transported from the tissue cells to the lungs
Describe the internal respiration process.
- oxygen diffuses from blood to tissue cells
- oxygen diffuses from the tissue cells to blood
When you contract your diaphragm and your external intercostal muscles you cause the intraplural cavity size to _________________.
increase.
When you contract your diaphragm and your external intercostal muscles you cause the intraplural pressure to ____________________.
decrease.
Define atmospheric pressure.
Pressure exerted by the air (gases) surrounding the body. At sea level, atmospheric pressure is 760 mm Hg (the pressure exerted by a column of mercury 760 mm high).
Does atmospheric pressure increase or decrease as elevation increases?
It decreases as you increase elevation.
What is the purpose of serous fluid in the lungs?
Prevents friction.
What are the steps involved in breathing in?
- Contract the diaphragm and the intercostal muscles. This will lift the rib cage up and out and increase the volume of the intrapleural space.
- The pressure will decrease to about 754 mmHg.
- Because there is less pressure pushing on them, the volume of the lung can increase. They expand and the pressure in the lungs decreases (from 760 to 759). Now air can come in. (had to alter the pressure gradient).
What is the typical intrapleural pressure?
756 mm Hg (minus 4 from atmospheric pressure)
What is the intrapulmonary cavity defined as?
pressure inside the lungs
What is intrapleural pressure defined as?
surrounding pressure in the pleural cavity
Define digestion.
System that processes food into absorbable units and eliminates undigestible wastes.
What are the functions of the digestive system?
- mechanical breakdown
- propulsion
- digestion
- absorption
- defecation
Which digestive system activity actually moves nutrients from the outside to the inside of the body?
The process of absorption moves nutrients into the body.
What are the four layers of the alimentary canal?
- mucosa
- submucosa
- muscularis externa
- serosa
What kind of tissue makes up the mucosa layer?
Nearly all is simple columnar, which is excellent for absorption and secreting.
What is the function of the layer of muscularis?
produce local movement
Describe how the muscularis layer works.
This layer is responsible for segmentation and peristalsis. It typically has an inner circular layer and an outer longitudinal layer of smooth muscle cells. In several places along the tract, the circular layer thickens, forming sphincters that act as valves to control food passage from one organ to the next and prevent backflow.
Define the enteric nervous system.
The enteric nervous system (enter = gut) is the in-house nerve supply of the alimentary canal. It is staffed by enteric neurons that communicate widely with one another to regulate digestive system activity.
What is primary hypertension?
Known as the silent killer. Blood pressure silently increases over time and is idiopathic in nature. No evident symptoms.
What are the short reflexes of the enteric nervous system?
Mediated entirely by enteric nervous system plexuses in response to stimuli within the GI tract. Control of the patterns of segmentation and peristalsis is largely automatic, involving pacemaker cells and reflex arcs between enteric neurons in the same or different organs.
What are the long reflexes of the enteric nervous system?
Long reflexes involve CNS integration centers and extrinsic autonomic nerves. The enteric nervous system sends information to the central nervous system via visceral sensory fibers. It receives sympathetic and parasympathetic motor fibers from the autonomic nervous system. These enter the intestinal wall to synapse with neurons in the intrinsic plexuses. Long reflexes can be initiated by stimuli arising inside or outside of the GI tract. In these reflexes, the enteric nervous system acts as a way station for the autonomic nervous system, allowing extrinsic controls to influence digestive activity (Figure 23.7). Generally speaking, parasympathetic inputs enhance digestive activity and sympathetic impulses inhibit them.
What is the major function of carbohydrates in the body?
The major function of carbohydrates in the body is to provide a ready, easily used source of cellular fuel
What are the three types of carbohydrates?
Monosaccharide
(simple sugars)
Disaccharides
(double sugar)
Polysaccharides
What makes up sucrose?
glucose + fructose
What makes up lactose?
glucose + galactose
What makes up maltose?
glucose + glucose
List the common monosaccharides.
glucose
fructose
galactose
List the common disaccharides.
sucrose
lactose
maltose
List the common polysaccharides.
starch
glycogen
What are proteins made up of and how can the body use them?
Protein is made up of amino acids and to be absorbed the body must break them down.
What are the three types of lipids?
triglycerides
phospholipids
steroids
To what level do you need to break down lipids for them to be usable in the body?
glycerol and fatty acids
Where would someone get nucleic acids within their diet?
The DNA/RNA found in the nucleus of cells within meat o plants.
What is the subunit of nucleic acids?
nucleotides
What are the components of a nucleotide?
- sugar
- phosphate
- base
What 3 main concepts govern the regulation of digestive activity?
- Digestive activity is provoked by a range of mechanical and chemical stimuli.
- Effectors of digestive activity are smooth muscle and glands.
- Neurons (intrinsic and extrinsic) and hormones control digestive activity.
What is the role of saliva in digestion?
- Cleanses the mouth
- Dissolves food chemicals so they can be tasted
- Moistens food and helps compact it into a bolus
- Contains the enzyme amylase that begins the digestion of starchy foods
- Contains the enzyme lipase that starts the minimal breakdown of lipids
How does amylase work in saliva to break down starch?
It attacks large carbohydrates and makes them a little bit shorter. They turn polysaccharides into oligosaccharides (bigger than a disaccharide).
What two enzymes in saliva play a role in the initial breakdown of food?
- Amylase starts to breakdown starchy foods
- Lipase starts the minimal breakdown of lipids
What are the three muscular layers of the stomach?
longitudinal, circular, and oblique
Where are the gastric folds located and what is their purpose?
They are on the internal surface of the stomach. They increase surface area and allow for greater stretch.
What layer does the surface mucosal cell belong to and what does it produce?
Mucosal layer. Produced alkaline mucous, which helps to protect the walls of the stomach from acid.
List the cells of the mucosal layer in the stomach wall.
surface mucous cells- mucous neck cells- parietal cells- chief cells- enteroendocrine cells
What are four different types of cells in the stomach mucosa and what are their functions?
surface mucous cells: produce alkaline mucous, which helps protect The wall of The Stomach from acid- parietal cells: produce HCl and intrinsic factor- chief cells: produces pepsinogen and lipase- enteroendocrine cells: produces gastrin hormone
What is the only thing in the stomach that you would die from if it didn’t happen?
not having intrinsic factor - need it for your blood cells to be produced
What 3 ways is the tissue of the small intestine modified to maximize surface area and absorption?
circular folds (force chyme to slowly spiral through lumen)- villi: fingerlike projections of mucosa- microvilli: cytoplasmic extensions (brush border) of mucosal cells on villi
Define partial pressure.
The pressure exerted by a single component of a mixture of gases.
What is the approximate percentage of nitrogen in atmospheric air?
78.6%
What is the approximate percentage of oxygen in atmospheric air?
20.9%
What is the approximate percentage of carbon dioxide in atmospheric air?
0.04%
What is the approximate percentage of water in atmospheric air?
0.46%
What is the partial pressure of nitrogen in atmospheric air?
597 mm Hg
What is the partial pressure of oxygen in atmospheric air?
159 mm Hg
What is the partial pressure of carbon dioxide in atmospheric air?
0.3 mm Hg
What is the partial pressure of water in atmospheric air?
3.7 mm Hg
What is the approximate percentage of nitrogen in the lungs?
74.9%
What is the approximate percentage of oxygen in the lungs?
13.7%
What is the approximate percentage of carbon dioxide in the lungs?
5.2%
What is the approximate percentage of water in the lungs?
6.2%
What is the partial pressure of nitrogen in the lungs?
569 mm Hg
What is the partial pressure of oxygen in the lungs?
104 mm Hg
What is the partial pressure of carbon dioxide in the lungs?
40 mm Hg
What is the partial pressure of water in the lungs?
47 mm Hg
How do we expire?
Need to increase the pressure in the lungs.
- Diaphragm and intercostal muscles relax; diaphragm recoils a little higher
- This decreases the volume of the pleural cavity to say 757 mmHg.
- Pushes on lungs and reduces the size of the lung. This increases pressure and forces air out.
How would a puncture to the lung do?
The pressure would change to that of the atmospheric pressure and the lung will collapse.
Is oxygen percentage higher in the atmosphere or the alveoli?
Higher in the atmosphere.
Is CO2 higher in the atmosphere or the alveoli?
Higher in the alveoli
Is water higher in the atmosphere or in the alveoli?
Higher in the alveoli.
Why can’t we match atmospheric pressures in our lungs?
Because our lungs use the same tube/path and we are always mixing fresh and stale air. We also don’t completely deflate our lungs.
Why aren’t we generally interested in nitrogen?
Its an inert gas that doesn’t really effect us unless we are scuba diving.
What process do we use to get O2 into the alveoli?
Simple diffusion
What is the normal pH range for the blood?
7.35 - 7.45 (it is slightly alkaline)
What is it called when blood pH is less below 7.35?
Metabolic acidosis
What could cause metabolic acidosis?
- too many hydrogen ions
- or not enough bicarb (HCO3)
Why might you end up with too many hydrogen ions?
An excessive amount of alcohol.
Why might you not have enough bicarbonate (HCO3)?
You have excessive diarrhea.
What is the role of the lungs in acid base balance?
1) metabolic: in this case the lungs are no the problem but can help resolve the problem
2) respiratory: only kidneys can help with this one
With metabolic acidosis, what direction do you want the equation to go?
HCO3- + H+ —-> H2CO3 ——–> CO2 + H2O
Is hyperventilation or hypoventilation involved in metabolic acidosis?
hyperventilation. It will drive CO2 out.
Which chemical has the most potent control over inspiration and is most closely controlled?
CO2
What is normal arterial Pco2 and what margin does it need to be maintained within?
40 mm Hg and within +/- 3 mm Hg
What is metabolic alkalosis?
- not the lungs causing the problem
- Blood pH is > 7.45
What are two reasons for metabolic acidosis?
- Too many hydrogens
2. Not enough bicarb
Why might you have too many bicarbs?
Severe indigestions or perhaps you take too many antacids.
Why might you not have enough hydrogen ions?
Excessive vomiting.
What direction do you want the equation to go during metabolic alkalosis?
CO2 + H2O —-> H2CO3 —–> HCO3- + H+
Is hyperventilation or hypoventilation involved in metabolic alkalosis?
hypoventilation
What is the most important factor influences breathing rhythm and rate?
Changing levels of CO2, O2, and H+ in arterial blood.
Where are the peripheral chemoreceptors located?
Found in the aortic arch and carotid arteries
Where are the central chemoreceptors located?
Located throughout the brain stem, including the ventrolateral medulla.
Where are two places that simple diffusion occurs during the process of respiration?
- at the alveoli
- at the tissue
Why doesn’t the oxygen value in the tissues change?
- cellular respiration
- most cells can’t store oxygen
What part of the hemoglobin does carbon dioxide attach to?
the globin part (protein)
List the 5 brush border enzymes in the small intestine.
- sucrase
- maltase
- lactase
- dextrinase
- glucoamylase
List the enzymes (in correct order) needed to break down glycogen.
Salivary amylase, Pancreatic amylase, dextrinase and glucoamylase, maltase
After proteins are broken down into amino acids what process is used to absorb them into the cells of the small intestine?
cotransport with sodium
Does the absorption of amino acids (and sodium) into the cells of the intestine wall require additional energy?
No, sodium spontaneously diffuse from high to low concentration transporting the amino acid for free
Is the movement of sodium and amino acids from the intracellular fluid, across the cell wall, into the blood, energetically a free process?
No. Although the amino acids do not require energy as they are moving from a high to low concentration the sodium potassium pump is required to move the sodium and this does require energy.
In terms of enzymes it is quite easy to break lipids down. Why is it difficult to digest them?
Because they are hydrophobic
What are the two roles of bile in lipid digestion?
Emulsification and micelle formation
Define lipase.
a pancreatic enzyme that catalyzes the breakdown of fats to fatty acids and glycerol or other alcohols.
Define mucous neck cell.
A gland cell in the stomach that produces a thin, soluble acidic mucus that is quite different from that secreted by the mucous cells of the surface epithelium.
Define parietal cell.
A gland cell in the stomach that simultaneously secrete hydrochloric acid (HCl) and intrinsic factor. HCl makes the stomach contents extremely acidic (pH 1.5–3.5), a condition necessary for activation and optimal activity of the protein-digesting enzyme pepsin. The acidity also helps digest food by denaturing proteins and breaking down cell walls of plant foods, and is harsh enough to kill many of the bacteria ingested with foods. Intrinsic factor is a glycoprotein required for vitamin B12 absorption in the small intestine.
Define chief cell.
The cuboidal chief cells produce pepsinogen, the inactive form of the pepsin. When these cells are stimulated, the first pepsinogen molecules they release are activated by HCl encountered in the apical region of the gland. But once pepsin is present, it also catalyzes the conversion of pepsinogen to pepsin. The activation process involves removing a small peptide fragment from pepsinogen, causing it to change shape and expose its active site. This positive feedback process is limited only by the amount of pepsinogen present. Also secrete lipases.
Define enteroendocrine cells.
Releases a variety of chemical messengers directly into the interstitial fluid of the lamina propria. Some of these, for example histamine and serotonin, act locally as paracrines. Others, such as somatostatin, act both as paracrines locally and as hormones that diffuse into the blood capillaries to influence several digestive system target organs. Gastrin, a hormone, plays essential roles in regulating stomach secretion and motility.
What are 4 activities of HCl?
- denatures proteins
- destroys bacteria
- activates and converts from pepsinogen to pepsin
- creates an ideal pH environment for optimal functioning of pepsin
Which nutrients end up getting transported into the blood?
- carbohydrates
- protein
- nucleic acids
Which nutrients end up getting transported into lacteals?
lipids
Why do tissues need oxygen?
They use it to make ATP.
T/F: Tissues all need the same amount of oxygen.
False, Tissues have different oxygen needs.
What is the typical oxygen level at tissues?
40 mm Hg
What is the typical level of CO2 at tissues?
45 mm Hg
What is the maximum saturation of O2 possible in pulmonary veins?
100 mm Hg
What is the name of the enzyme that enables carbon dioxide to combine with water in the red blood cells?
carbonic anhydrase
With metabolic acidosis, do we use hyperventilation or hypoventilation?
Hyperventilation; increasing our breathing rate so we can get rid of carbon dioxide and water
True or false: bicarb has a strong effect on the pH of blood.
False. Due to the chloride ion shift, bicarb does not have a strong effect on blood pH.
What change in PCO2 in arterial blood would trigger peripheral chemoreceptors?
+/- 3 mm Hg
What activates central chemoreceptors?
Activated by hydrogen ion concentration, that is directly related to CO2 as it is small and non polar and can cross the blood brain barrier
At what level does O2 become the major impactor of breathing?
below 60 mm HG
Where does most digestion take place?
small intestine
What is the site of production for CCK?
duodenal mucosa
What is the stimulus for production of CCK?
fatty chyme (also partially digested proteins)
What are the target organs for CCK?
- stomach
- liver
- pancreas
- gallbladder
- hepatopancreatic sphincter
What does CCK do at the stomach?
Inhibits stomach’s secretory activity.
What does CCK do at the liver?
Potentiates secretin’s actions on these organs (liver and pancreas)
What does CCK do at the pancreas?
Increases output of enzyme-rich pancreatic juices.
What does CCK do at the gallbladder?
Stimulates the gallbladder to contract and expel stored bile.
What does CCK do at the hepatopancreatic sphincter?
Relaxes the sphincter to allow entry of bile and pancreatic juice into duodenum
What is the site of production for gastric inhibitory peptide?
Duodenal mucosa
What is the stimulus for the production of gastric inhibitory peptide?
Fatty chyme.
What are the target organs for gastric inhibitory peptide?
- Stomach
- Pancreas
What does gastric inhibitory peptide do at the stomach?
Inhibits HCl production
What does gastric inhibitory peptide do at the pancreas?
stimulates insulin release
What is the site of production for gastrin?
stomach mucosa
What is the stimulus for the production of gastrin?
Food in the stomach; acetylcholine released by nerve fibers
What are the target organs for gastrin?
- Stomach (parietal cells)
- small intestine
- ileocecal valve
- large intestine
What is gastrin doing at the stomach?
- Increases HCl production by parietal cells
- stimulatse gastric emptying
What is gastrin doing at the small intestine?
Stimulates contraction of intestinal muscle
What is gastrin doing at the ileocecal valve?
relaxes ileocecal valve
What is gastrin going to do in the large intestine?
stimulates mass movement
What is the site of production of secretin?
Duodenal mucosa
What stimulates the production of secretin?
acidic chyme (and partially digested proteins and fats)
What are the target organs of secretin?
- stomach
- pancreas
- liver
What is secretin doing in the stomach?
Inhibits gastric gland secretion and gastric motility
What is secretin doing in the pancreas?
Increases output on pancreatic juice rich in bicarbonate ions; potentiates CCK action
What is secretin doing at the liver?
Increases bile output.
Which gland cell produces HCl and intrinsic factor?
parietal cells
Which gland cells produce pepsinogen and small amounts of lipase?
Chief cells
Which gland cell produces gastrin?
Enteroendocrine
What are duodenal glands for?
When food arrives in the stomach, it is very acidic. Duodenal glands release an alkaline mucus rich in bicarbonate to neutralize.
What layer are the duodenal glands in?
Submucosal layer.
What do Paneth cells do and where are they?
They are located at the bottom of the villi and they are going to produce antimicrobial secretions to kill off bacteria. Produces a particular enzyme called lysozyme that is really good at killing off bacteria.
What do goblet cell produce? Where are they?
Mucous. In the villi in small intestine.
What do enteroendocrine cells in the small intestine produce?
Hormones. They produce CCK, GIP, and secretin. Gastrin is produced in the stomach.
What do enterocytes do in the small intestine?
Very much responsible for absorption. Also produce enzymes. A lot are covered in microvilli. Brush border enzymes.
What enzyme attacks proteins in the stomach?
pepsin
What enzyme produced by the small intestine attacks protein?
aminopepsidase. Attacks the amine end of a polypeptide.
Where do we get most of the protein digesting enzymes from in the small intestine?
From the pancreas.
True or false: The small intestine produces enzymes to breakdown lipids.
False. Enzymes in the small intestine that breakdown lipids come from the pancreas.
What groups of enzymes does the small intestine produce that attack nucleic acids?
- Nucleosidases
- Phosphatases
