Lecture 2 - Bio 2AO3 L10 Lecture 10 Circulation IV -NFP +...

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+ NFP -NFP Bio 2AO3 – L10 Lecture 10 – Circulation IV 1. Extrinsic Controls 1. Outside of area (from Nervous System for ex) 2. SNS: 1. Arterioles highly innervated and have – adrenergic α receptors (post-synaptic) which trigger vasoconstriction through neurotransmitter NorEpinephrine (NE) 1. Innervated – lots of nerves end up at arterioles 2. Changes above or below tonic constriction (nerves always active) 1. Nerve that ends at smooth muscle is always active 2. Fully relaxed arterioles only vasoconstrict (no vasodilation) 3. Important role in controlling whole body arterial blood pressure distribution 1. PSNS : 1. Not a big role in vascular smooth muscle regulation 1. Hormones : 1. Epinephrine through adrenal medulla causes vasoconstriction - via – adrenergic α receptors, vasodilation via B 2 – adrenergic receptors 2. Skeletal muscle has both and B α 2 – adrenergic receptors 1. In most vascular beds α outnumber B 2 (except in skeletal muscle) 1. In most arterioles 2. Epinephrine has greater affinity for B 2 receptors 3. Receptors on arterioles and smooth muscle 1. Binding of these receptors contraction/dilation of smooth muscle 1. Paracrine + autocrine agents regulate arterioles 2. SNS and PSNS – the two pathways of the autocrine nervous system 3. At Rest vs. exercise 1. Blood flow in skeletal muscle increases drastically during exercise and blood flow to other organs and parts decrease
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Bio 2AO3 – L10 2. High concentration of Epi – binds to both and B α 2 vasodilation in skeletal muscle vascular beds (high proportion of B 2 -adrenergic receptors 3. Decrease TPR (Total peripheral resistance) 1. radius -
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This note was uploaded on 03/26/2011 for the course BIOLOGY 2a03 taught by Professor Nurse during the Spring '10 term at McMaster University.

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Lecture 2 - Bio 2AO3 L10 Lecture 10 Circulation IV -NFP +...

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