Nasal vasculature

Nasal vasculature may offer some insight into this question, though research to date has been equivocal. Nasal turbinate vessels can be classified as either capacitance vessels or resistive vessels. Capacitance vessels appear to vasodilate in response to infection while resistance vessels appear to respond to cold stimuli by vasoconstriction. Buccal vascular structures also respond to thermal stimuli but appear to respond principally to cutaneous stimuli. How pharyngeal and tracheobronchial submucosal vessels react to thermal stimuli is not known, though cold-induced asthma is believed to result from broncho-spasms caused by susceptible bronchial smooth muscle responding to exposure to cold dry air.- This asthmatic response suggests an inadequate vascular response to surface cooling. 

Wood-Baker R, Lau L, Howarth PH. Histamine and the nasal vasculature the influence of HI and H2-histamine receptor antagonism. Clin Otolaryngol 1996 21 348-352. 

The direction of arterial blood flow in the nose runs anteriorly against inspiration. Blood vessels are arranged in such a manner as to provide an erectile capacity to the mucosa enabling the airway to widen and narrow. Blood flow through the autonomically controlled vasculature of the nasal tissue is of importance in the conditioning of inspired air. 

The nasal mucosa is highly vascular superficial and deep layers of arterioles supply the lamina propria and between the venules and capillaries there are numerous sinuses or venous lakes which are linked to erectile tissue, particularly in the middle and inferior turbinates, which enable the airways to widen or narrow. This autonomically controlled vasculature of the nasal tissue, in combination with its rich supply of secretory cells, is of importance in the modification of inspired air. 

The principal function of the nasal cavity in man is that of airconditioning. The anatomy of the nose permits intimate contact between the inspired air and the mucosal surfaces enabling the air to be warmed and humidified by the vasculature and secretions of the epithelium. Inspired air of 23 °C and 40% relative humidity can be brought to 32 °C and 98% relative humidity upon inhalation via the nose. 

Because of its rich vasculature and highly permeable structure, the nasal route can be used as an alternative to parenteral routes of delivery. It circumvents hepatic... 

Whereas the suspected mechanism for ischemic stroke is analogous to that leading to myocardial infarction (hypoperfusion distal to a critical lesion), intracerebral bleeding (14,15) may be more difficult to explain. The authors considered the likelihood of sildenafil-induced spontaneous intracerebral hemorrhage due to the vasodilatory effects of the drug on the cerebral vasculature (as evidenced by headache, flushing, and nasal congestion). 

Injury of any tissue gives rise to an immediate inflammatory response and it is probable that this initial response is primarily aimed at priming the process of repair. It is likely that adaptive immunity has evolved in the context of tissue damage induced by infection and the production of an immune response is seen to be most efficient in those tissues most likely to be at risk of a primary infection, e.g., the nasal-oral mucosa, the respiratory, intestinal, and genitourinary surfaces, and the dermis. The CNS is not a site of primary infection and the invasion of the CNS by organisms following systemic infection is limited, presumably by virtue of the properties of the brain vasculature, and when it occurs it seems to reflect more the adaptive ability of the infective agent. 

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