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Pharyngeal arches

The first,second, and fifth aortic arches completely regress, leaving no structures or vestiges in the adult. The third aortic arch forms the common and proximal internal carotid arteries. 

The fourth aortic arch gives rise to part of the true aortic arch and a position of the subclavian arteries. The sixth aortic arch gives rise to the pulmonary arteries and the ductus arteriosus.

High & Low frequency sounds

Low frequency sound is best detected at the apex of the cochlea near the helicotrema. High frequency sound is best detected at the base of the cochlea near the oval and round windows

The Thalamus as its ''Relay'' function

the thalamus is a part of diencephalon and has multiple functions. It translates information from all sensory pathways other than Olfaction and selectively distributes those impulses to appropriate parts of the cortex (''relay'' function). The following thalamic nuclei receive input from sensory pathways:

1.Ventral posterolateral (VPL) receives input from the spinothalamic tract (pain and temperature sensation) and medial lemniscus(position and proprioception). It transmits impulses to primary somatosensory cortex (Brodmann areas 3,1 & 2).
2.Ventral posteromedial nucleus (VPM) receives inputs from the trigeminal and gustatory pathways and transmits them to the primary sensory cortex (Brodmann's areas 3, 1 & 2).
3.Lateral geniculate body is a ''relay'' nucleus for the vision pathway. It receives impulses from the optic nerve and transmits them via the optic radiations to the visual cortex (calcarine sulcus)
4.Medial geniculate body is a part of the auditory pathway. It receives impulses from the superior olivary nucleus and the inferior colliculus of the pons, and projects them to the auditory cortex of the temporal lobe (Brodmann areas 41 & 42)

The olfactory tract is the only sensory pathway where input is not processed through thalamus.

IBS and diet

Upto 20% may benefit from a wheat-free diet, some may respond to lactose exclusion, excess intake of caffeine or artificial sweetners such as sorbitol should be addressed.

-The role of probiotics has yet to be clearly established
-Patient's with intractable symptoms sometimes benefit from several months of therapy with Amitriptyline

-Fibers-rich food such as fruits,vegetables and whole grains (constipation)
-Soluble fibers - apples, berries, carrots and oat meal.
-Gluten free Diet may reduce symptoms - (gluten is in bread and pasta)
-Low Fat Diet-
-Drink plenty of water
-Decrease your caffeine intake
Treatment :

Tegaserod : main problem is Constipation
Alosetron : main problem is Diarrhea

Antispasmodic : Hyoscyamine , Dicyclomine

Remember : Certain foods can help IBS, but everyone is different

reference :
and Davidson Internal Medicine

Enzyme-linked immunosorbent assay (ELISA)

Enzyme-linked immunosorbent assay (ELISA)

assays are serological tests that examine for the presence or adsence of antibody in human serum directed against the pathogen being tested. ELISA is the first test done in assessment of a patient with suspected HIV infection and positive ELISA results are confirmed by western blotting.The most frequently used form of ELISA is the indirect form where the test detects antibody in the patient's serum directed against a known antigen. The specific steps of this assay are outlined below.

1.Known antigen,such as antigen from the HIV virus,is fixed to the bottom of a well.

2.Patient serum is then added to these wells containing known antigen. If present, patient antibody specific for the known antigen will bind the antigen and remain fixed to the well.

3.The plate is washed to remove unbond patient antibody. After this wash, only the patient antibody-known antigen complexes(Patient anti-HIV antibody complexed to HIV antigen ) remain attached to the well.

4.Next a second antibody is added to the wells. This antibody is an anti-human IgG antibody, and as such it will bind to the patient immunoglobulin that was bound to the fixed antigen in the previous steps. These second antibodies are coupled to the substrate-modifying enzyme (''enzyme linked'')

5.Wash the wells so that excess unbound enzyme-linked antibodies are removed.

6.Apply a substrate, such as chromogen, which is converted by the enzyme to elicit a chromogenic or fluorescent signal.

Insulin therapy and its types

Insulin types depicted on the graph below : Regular insulin is preferred in the initial treatment of Diabetic ketoacidosis(DKA). Recognize the different types insulins and their durations of action.

Line A- rapid-acting (e.g., lispro)
Line B-regular
Line C-NPH
Line D-Lente
Line E-Ultralente
Line F-Glargine

Diabetic patients need two types of insulin: both a basal long-acting insulin and a short acting insulin. 
The latter covers post-meal hyperglycemia. The best basal, long-acting insulin is glargine insulin(Lantus), which is supplemented by at least 3 shots of short-acting insulin at mealtimes. Before the advent of glargine, NPH was the best long-acting basal insulin.
Since NPH is only good for 12-18 hours, patients need two shots per day, plus the short-acting mealtime shots. Glargine allows only four shots per day, while the use of NPH requires five shots.

The best short-acting insulins are aspart and lispro. Before the advent of these two drugs, regular insulin was the best option for postmeal hyperglycemia. Insulin aspart and insulin lispro have a very rapid onset of action.

The most important complications of Crohn's disease

The most important complications of Crohn's disease are as follows:

1.Intestinal: Fistulas,strictures,abscesses,perianal disease,increased risk of adenocarcinoma

2.Skin: Erythema nodosum,pyoderma gangrenosum

3.Joints: Arthritis, ankylosing spondylitis

4.Eyes: Iritis,uveitis, episcleritis

5.Malabsorption: Oxalate kidney stones, anemia, hypoproteinemia, B12 and folate deficiencies ,gallstone

6.Liver: Primary sclerosing cholangitis ,increased risk of cholangiocarcinoma.