1141 Immune/Respiratory/CV/Digestive Case: Walter Has a Blind Date with Anna Phy
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Question
1141 Immune/Respiratory/CV/Digestive Case: Walter Has a Blind Date with Anna Phylaxis!
1. Walter Wheezer was taking a lunch break from beach volleyball, enjoying a meal of grilled salmon, baked potatoes, and a salad at a seaside restaurant holiday break, He was anticipating a long, exciting afternoon of beach volleyball, swimming, and surfing with his friends. Unfortunately, he grabbed a peanut butter cookie and stuffed it into his mouth on the way out to the beach. Walter is allergic to peanut butter.
Within a few minutes Walter began to feel light headed and weak. His skin became red and blotchy with a rash he had never seen before, and he began to have difficulty breathing. Twenty minutes later he was unconscious on the sand with no respiration and a rapid, weak pulse. Walter was experiencing anaphylactic shock!
a. Why did his immune system react this way? (describe the components that activated this response.
b. What respiratory and vascular tissues were affected and what happened in each of them?
c. Explain how Walter’s reaction will affect the following? Give reasons:
Capillary filtration and reabsorption
Peripheral resistance
Blood pressure
Venous return
arterial blood PO2
arterial blood PCO2
blood pH
hemoglobin saturation
d. How would the changes in PO2, PCO2, pH, and temperature affect his hemoglobin?
e. How would the respiratory chemoreceptor reflex attempt to restore homeostasis?
f. How would the baroreceptor reflex react?
g. What medical interventions could possibly help in Walter’s case?
h. What is cardiogenic shock?
What is the difference between neurogenic, septic, and anaphylactic shock?
What do all three types of shock have in common?
2. Briefly describe the digestion of Walter’s meal (after he recovered) by listing the portions of the digestive tract, processes that take place, other organs that secrete, and their secretions in order from oral to anal end of the digestive tract. You may the table below.
Part of Dig. Tract
Processes
Other organs involved
Secretions
Functions of secretions
Oral cavity, tongue and teeth
Mastication, lubrication, begin lipid and carbohydrate digestion
Salivary glands,
Tongue, teeth
Mucous
Lingual lipase
Amylase
IgA antibodies
Lubricates/moisturizes
Lipid digestion
Starch digestion
Immune protection
3. Why was the meal Walter ate a good choice to maintain steady blood glucose levels during the afternoon if he had avoided the peanut butter. (Hint: look up the intestinal phase of regulation of gastric secretion.)
Include the roles of CCK, secretin, gastrin, and insulin which are the primary hormones involved. Also include the nutrients or conditions that activate their secretion.
Part of Dig. Tract
Processes
Other organs involved
Secretions
Functions of secretions
Oral cavity, tongue and teeth
Mastication, lubrication, begin lipid and carbohydrate digestion
Salivary glands,
Tongue, teeth
Mucous
Lingual lipase
Amylase
IgA antibodies
Lubricates/moisturizes
Lipid digestion
Starch digestion
Immune protection
Explanation / Answer
a)
Activation of mast cells and basophils through a mechanism involving crosslinking of immunoglobulin (Ig)E with the high-affinity receptors for IgE. Soon after the activation, mast cells and basophils release rapidly preformed mediators that include histamine, tryptase, proteoglycans and carboxypeptidase A.
Downstream activation of phospholipase A2, lipoxygenases and cyclooxygenases release metabolites of arachidonic acid like leukotrienes, prostaglandins and platelet activating factors. The cytokines and tumor-necrosis factor-alpha are released as mediators which act as responsible for anaphylaxis reaction.
In this case, peanut butter stimulated the B cells to produce IgE antibodies that are specific to a particular antigen leading to Type I hypersensitivity.
b)
The synthesis of lipid mediators from arachidonic acid like leukotrienes, histamines and prostaglandins resulted in vasodilation and smooth muscle contraction. The immediate response of type I hypersensitivity release vasoactive amines while late phase response shows the release of cytokines.
Histamines are known to stimulate vasodilation, vascular permeability, increase heart rate, cardiac contraction and glandular secretion. Prostaglandin D2 triggers bronchoconstriction in pulmonary and vascular tissues, leukotrienes are known to enhance airway remodeling. Platelet activating factor is an efficient bronchoconstrictor and increases vascular permeability. TNF-alpha triggers the synthesis of neutrophils and increases chemokine synthesis. All these effects contribute overall to the pathophysiology of anaphylaxis.
c)
The difference between neurogenic, septic and anaphylactic shocks
Anaphylactic shocks are caused due to the allergic reactions created by the allergens. Septic shocks occur due to infections and neurogenic shocks are caused due to the damage caused to the nervous system. The common symptoms of these three shocks include low blood pressure and vasodilation.
d)
Cardiogenic shock is a condition where the heart is sufficiently damaged to be not able to supply blood to the tissues. The other medical conditions that might lead to the cardiogenic shock include acute myocardial infarction, arrhythmias, dilated cardiomyopathy and acute myocarditis. The major symptoms of this shock are absence of pulse due to tachyarrhythmia and enhanced jugular venous pressure leading to distended jugular veins. Treatment to this condition includes administering medications that increase the heart pumping, oxygen therapy and cardiac drugs.
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