21/05 Flashcards
chronic bronchitis
Chronic exposure to smoking or air pollutants causes mucus hypersecretion in the bronchi
Emphysema
irreversible enlargement of the airspaces distal to the terminal bronchioles, due to destruction of their walls.
reduces the alveolar surface area thus impeding efficient gaseous exchange.
α1-antitrypsin is responsible for inhibiting excessive activity of neutrophil elastase.
normal balance of proteases and antiproteases is lost. The stimulated neutrophils release free radicals that inhibit the activity of α1-antitrypsin.
This results in loss of elastic recoil and subsequently airway collapse during expiration and air trapping.
emphysema in smoking
centriacinar
α1-antitrypsin deficiency emphysema
panacinar
alveolar ventillation rate
Ventilation rate x (Tidal volume - Dead space)
Hypercalcemia symptoms
stomach upset, nausea, vomiting and constipation. Bones and muscles
excess calcium in your blood was leached from your bones, which weakens them. This can cause bone pain and muscle weakness
can cause RDS
Restrictive spirometry pattern
Reduced FEV1 (<80% of the predicted normal) Reduced FVC (<80% of the predicted normal) FEV1/FVC ratio normal (>0.7)
pO2 is about
100mmHg.
mechanism by which a pulmonary embolism
can cause respiratory failure
High V/Q ratio not alveolar hypoventilation
asthma pathophysiology
Airway inflammation leading to bronchial smooth muscle hypertrophy
REVERSIBLE with bronchodilators
What degree of overlap is present between the filaments at rest that allows for optimum tension generation?
The myosin and actin filaments overlap enough to form the maximum number of cross-bridges.
surfactant is a
phospholipid
total lung capacity
total volume of air in the lungs after a maximal inhalation.
Inspiratory capacity
volume of air that can be forcefully inhaled after a quiet exhalation
What effect does Parathyroid Hormone have on the kidneys
Decreases calcium excretion and increases phosphate excretion
normally released in response to hypocalcaemia
increase blood calcium concentrations by decreasing calcium excretion in the urine (by increasing reabsorption), acts on the kidneys to increase urinary phosphate excretion (by reducing reabsorption).
This prevents calcium phosphate precipitates forming in the blood, allowing calcium levels to safely increase.
Vital capacity
inhale as much as she can and then exhale as much as she can.
pathophysiology of a reduced forced vital capacity (FVC) in a patient with kyphoscoliosis?
The abnormal curvature of the spine reduces chest wall compliance during inspiration
ca ions stored in
sarcoplasmic reticulum
Type 1 pneumocytes
Very thin squamous cells which cover around 97% of the alveolar surface
Type 2 pneumocytes
Cuboidal cells
Secrete surfactant
Start to develop around 24 weeks gestation, however adequate surfactant production does not take place until around 35 weeks so premature babies are prone to respiratory distress syndrome
Can differentiate into Type 1 pneumocytes during lung damage
Perfusion-limited exchange
gas equilibrates early along the length of the pulmonary capillary, therefore the partial pressure of the gas in the arterial blood equals that in the alveolar air
the only way to increase diffusion of a gas is therefore to increase blood flow
Oxygen (normal conditions)
Nitrous oxide
Carbon dioxide
Diffusion-limited exchange
gas does not equilibrate by the time the blood has reached the end of the pulmonary capillary
a partial pressure gradient is therefore maintained between the arterial blood and the alveolar air
Oxygen (during strenuous exercise)
Oxygen (lung fibrosis)
Oxygen (emphysema)
Carbon monoxide
Club cells
non-ciliated dome-shaped cells found in the bronchioles
pancreatic enzymes
trypsin, amylase, lipase
The facial (VII) and glossopharyngeal (IX) nerves
parasympathetic nerves responsible for carrying afferent input to the medulla.
facial- taste
gp- swallowing
Efferent pathways to the sublingual and submandibular glands
facial nerve (CN VII) and efferent pathways to the parotid gland are from the glossopharyngeal nerve (IX).
how fructose is transported into enterocytes from the intestinal lumen?
facilitated diffusion
salicylates
NSAIDs
coeliac disease histology
Villous flattening of the small bowel
why erythromycin can cause gastrointestinal (GI) disturbance?
motilin agonist and increases GI motility.
degraded to an intermediary that serves as a motilin receptor agonist when it reaches the low pH of stomach.
stimulates a G-protein coupled receptor (GPCR) pathway which initiates the smooth muscle cells of the muscularis layer in the GI tract to contract.
causes peristaltic waves subsequently leading to GI upset symptoms such as stomach cramps and diarrhoea.
gastrectomy to remove most of the gastric fundus causing heart burn and reflux.
When stretched by food, the stomach wall in the fundus relaxes to accommodate the food and reduce intra-abdominal pressure. Gastrectomy reduces this ability to accommodate changes in gastric pressure, increasing the risk of retrograde expulsion (reflux).
secreting the aqueous component of pancreatic juice?
cantriacinar cells
Cephalic phase
exocrine pancreatic secretion (20-25%) is stimulated by sight, smell taste and thought of food.
control of the vagus nerve. Sensory inputs travels to the brainstem and is then transmitted to the exocrine pancreas via the vagus nerve.
Vagal efferents release acetylcholine (ACh) which stimulates exocrine secretion.
The exocrine pancreas also secretes vasoactive intestinal peptide (VIP) during the cephalic phase. VIP increases stimulation secretion of aqueous bicarbonate.
Gastric phase
presence of food in the stomach initiates the gastric phase of pancreatic secretion.
The gastric phase accounts for 10% of pancreatic secretion.
The vagus nerve stimulates the antrum of the stomach resulting in pancreatic amylase release due to a vagovagal reflex.
Intestinal phase
acidic chyme in the duodenum stimulates the intestinal phase of exocrine pancreatic secretion. 50 - 80%
chyme in the duodenum stimulates secretin and cholecystokinin (CCK) release from S cells and I cells in the duodenum respectively.
Entry of acidic chyme into the duodenum stimulates release of secretin from S cells into the blood. This binds to centroacinar cells in the exocrine pancreas and stimulates aqueous bicarbonate release.
CCK is released in the presence of semi-digested fats and peptides in the duodenum: It is released into the blood and binds to acinar cells causing pancreatic enzymes to be secreted.
Vagovagal enteropancreatic action is mediated by M1 and M3 muscarinic receptors in the intestinal phase.
Vagal stimulation activates pancreatic enzyme and bicarbonate secretion.
Vitamin A deficiency
xerophthalmia which poses the risk of blindness. It can also lead to night blindness, which is the first sign many notice.
Bone growth is impaired and is slower than usual, as is tooth development.
More prone to infections.
Vitamin E deficiency
Retinopathy
Ataxia
Peripheral neuropathy
Impaired immune response
Vitamin K deficiency
easy bruising
medication that prevents bile reabsorption , how works
Increases faecal bile acid excretion
This is the correct answer. Cholesterol is metabolised to form bile acids. The rate of bile acid production in the liver is inversely proportional to the rate at which bile acids are returned to the liver via intestinal absorption into the enterohepatic circulation. Cholestyramine is a bile acid sequestrant. It binds bile in the gastrointestinal tract, preventing reabsorption and increasing bile acid excretion in the faeces. As less bile acids are returned to the liver, bile acid synthesis (which requires cholesterol breakdown) increases to normalise bile acid concentration in the blood. This reduces cholesterol levels.
Post-hepatic jaundice
bile drainage is prevented (cholestasis), characteristically produces dark urine and pale stools.
This leads to less bilirubin being converted to stercobilin (resulting in pale stools) and more excretion of bilirubin in the urine (resulting in dark urine).
Reduced activity of the CFTR channel results in
reduced transport of chloride ions out of epithelial cells. In the apical membrane of duct cells, HCO3- is transported out of the cell in exchange for Cl- via a transporter protein. As there is reduced concentration of chloride ions available to be brought into the cell in exchange for bicarbonate ions to be transported out of the cell, this results in a low HCO3- concentration in the pancreatic exocrine secretions.
bowel cancer and vomiting
Bowel cancer is a cause of intestinal obstruction. Bowel obstruction leads to gastrointestinal distension, which is a trigger of the vomiting reflex.
inhibits gastric emptying?
Duodenal distension chyme cck protien and fat ppi low temps GLP-1 agonists for diabetes
inhibits gastric emptying?
Duodenal distension chyme cck protien and fat ppi low temps GLP-1 agonists for diabetes
Factors promoting gastric emptying
more volume antral distention protein fastest then carb then fat gastrin Motilin is released by Mo cells of the duodenum and jejunum which enhances the peristaltic waves allowing food to pass through the stomach and into the gut during the fasting/interdigestive period.
metoclopramide and domperidone
Causes relaxation of the lower oesophageal sphincter and increases gastric motility, leading to increased gastric emptying.
Erythromycin is a motilin agonist which enhances peristaltic waves throughout the gut which helps to empty remaining food in the stomach during the fasting period.
