Biology 2672a: Comparative Animal Physiology Circulation II: Regulation of Circulation.

Slides:



Advertisements
Similar presentations
Regulation of Blood Flow and Pressure
Advertisements

Blood pressure 1.
Circulatory Adaptations to Exercise
Chapter 19 - The Cardiovascular System: Blood Vessels $100 $200 $300 $400 $500 $100$100$100 $200 $300 $400 $500 Blood Vessel Structure Blood Vessel Function.
THE CARDIORESPIRATORY SYSTEM Chapter 9. Cardiorespiratory System  What are the functions of the cardiorespiratory system? –Transport O 2 to tissues and.

Circulatory System of a Mammal
Cardiovascular System: Blood Vessels and Circulation
BLOOD PRESSURE - PHYSIOLOGY ROBYN DANE AND KATY DAVIDSON.
Transport & Maintenance
 If you could join all the blood vessels in your body in a straight line, it would be about 100,000km long!  Our blood vessels are not one long tube.
THE BLOOD VESSELS & BLOOD PRESSURE Lecture – 9 Dr. Zahoor Ali Shaikh 1.
Basic Definitions Arteries carry blood away from the heart
BLOOD CIRCULATION. Copyright 2009, John Wiley & Sons, Inc. STRUCTURE AND FUNCTION OF BLOOD VESSELS 5 main types Arteries – carry blood AWAY from the heart.
Blood vessels Arteries The blood from the heart is carried through the body by a complex network of blood vessels Arteries take blood away from.
Name the layers of the blood vessels.
Chapter 18 Blood Vessels and Circulation Inner Surface of an Artery
Heart and Blood Vessels. Major Arteries and Veins Subclavian artery Subclavian vein Jugular vein Carotid artery Superior vena cava Inferior vena cava.
The Cardiovascular System blood vessels. Blood Circulation Blood is carried in a closed system of vessels that begins and ends at the heart.
Circulation.
Year 10 GCSE Body Systems..
carry blood away from heart usually O 2 rich Pulmonary artery – artery leading from heart to lung (deoxygenated) connective tissue and muscle walls elastic.
Copyright © 2009 Pearson Education, Inc. Heart and Blood Vessels Ch. 8 Major Arteries and Veins Figure 8.9 Subclavian artery Subclavian vein Jugular vein.
21-1 Anatomy and Physiology, Sixth Edition Rod R. Seeley Idaho State University Trent D. Stephens Idaho State University Philip Tate Phoenix College Copyright.
Chapter 16.2: Blood Flow Through Blood Vessels. Resistance -Vascular Resistance: the opposition to blood flow due to friction between blood and blood.
Aims Regulation of vascular tone. Capillaries Readings; Sherwood, Chapter 10.
The Cardiovascular System: Blood Vessels and Circulation
Cardiovascular Block Coronary Circulation
Circulation V. Veins Regulation of Arterial Blood Pressure.
Chapter 9: Circulatory Adaptations to Exercise
Part 3: Blood Vessels function structure -location
Regulation of the cardiovascular activity
The Circulatory System. The Circulatory System The circulatory system is made of: The circulatory system is made of: The Heart The Heart Arteries and.
Chapter 23 Blood Vessels. Blood Vessel Tunics Walls of blood vessels have three layers, or tunics 1.Tunica externa (adventitia) – anchor BV to an organ.
Circulatory System.
Blood Pressure Regulation
University of Jordan 1 Cardiovascular system- L6 Faisal I. Mohammed, MD, PhD.
Human Anatomy and Physiology
Circulation. The circulatory system acts as a transportation network for our cells and tissues It supplies nutrients and removes wastes It is km.
2/25/08 Blood Vessels Chapter 19 – Day 1. 2/25/08 Blood Vessel Structure Fig
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Human Anatomy & Physiology SEVENTH EDITION Elaine N. Marieb Katja Hoehn Active.
Blood circulation & its short term regulation Dr. Wasif Haq.
Learning Objectives: 1. To understand how blood pressure and velocity changes during exercise. 2. To know the mechanisms that aid venous return. 3. To.
1 Special circulations, Coronary, Pulmonary… Faisal I. Mohammed, MD,PhD.
Blood Vessels & Blood Pressure
HEART & CIRCULATION Chapters 14 & 15. The cardiovascular system Structure of the The cycle Structure and organization of.
Question 1 Which of the following is NOT true of the parasympathetic control of the heart? A. It affects muscarinic receptors. B. It decreases heart.
Chapter 9 Circulatory Systems Sections
BLOOD VESSELS Arteries Away from the heart Oxygen rich Elasticity and contractility (ANS, sympathetic) Divide into smaller vessels- arterioles Which divide.
Do Now 11/7/14 What is the pathway that an electrical impulse follows from the brain to causing a heart beat? What are the different mechanisms that regulate.
Cardiovascular Dynamics Part 2 Biology 260. Maintaining Blood Pressure Requires – Cooperation of the heart, blood vessels, and kidneys – Supervision by.
Blood Pressure Regulation
PHED 1 Applied Physiology Blood Vessels and the Vascular Shunt
Blood Pressure Regulation
6.2 The Blood System.
Blood Vessels Compare the structure and function of blood vessels. (GLOs: D1, E1) Examples: diameter, elasticity, muscle layers, valves, what they transport.
Pressure and Resistance
Cardiovascular System: Circulation Pathways and BP Regulation
6.2 The Blood System.
Chapter 19 Blood Vessels Cardiovascular System.
The Blood System.
4 November 2011 Properties of Blood Vessels
Regulation of Blood pressure Dr Farzana Salman.
Heart: valves, vessels and nodal tissue
Unit J. Circulation and Blood .
Human Anatomy and Physiology II
The Cardiovascular System
Review of Microvascular Anatomy and Physiology
Presentation transcript:

Biology 2672a: Comparative Animal Physiology Circulation II: Regulation of Circulation

What happens in the ‘systemic circuit’?

The ‘Systemic circuit’  Blood is delivering oxygen and nutrients and picking up waste products (and delivering them to the kidneys)  Organs & muscles  Linear flow rate is reduced Cross-sectional area increases

Major Arteries  Muscular, elastic thick walls (smooth muscle and elastin)  Pressure of kPa  Elastic Dampen pressure differences Store some elastic energy  e.g. Aorta, carotid artery, femoral artery  16/10 kPa

Terminal arteries  12/8 kPa

Arteriole: 8/3.5 kPa Capillaries: c kPa Venules: c kPa Fig Right ventricle then increases pressure to c. 1.9 kPa for passage through lungs

Precapillary sphincter Can close off flow to capillary bed Arteriolar-venular anasomosis Allows blood to bypass the capillary bed Fig

Veins  Low pressure  Have a system of one-way valves  Much thinner-walled than arteries

Pressure drop across vascular system Fig b

What about birds?  Broadly similar Heart pumps more and faster to meet greater oxygen demands Higher pressures

What about birds?  Jugular Anastamosis

Gravity also affects pressure ΔP = ρgΔh Fluid density (mercury>seawater>water>oil) Acceleration due to gravity Height difference across the system See Fig 24.7

The problem of being a giraffe  The brain of a standing giraffe is 2m above its heart  To maintain a pressure of c. 13 kPa in brain arteries, needs an aortic pressure of c. 29 kPa (!)

 Tight skin on legs  Muscular arteries  High interstitial fluid pressure, efficient return of venous blood

Giraffes have a drinking problem  Very high pressure blood into brain  Blood can pool in brain ΔP = ρgΔh

Solving the giraffe drinking problem  Vasodilation in lower body reduces blood pressure  Elastic arteries near brain absorb some increased pressure  One-way valves in jugular vein prevent backflow of blood into head

Brain Heart Kidneys – Require a regulated blood pressure to function Need blood flow to be maintained

Animals with a closed circulatory system are able to regulate  Where blood goes  How much of it goes there  Need to respond to central requirements e.g. fight-or-flight  Also need to respond to local conditions O 2 demand, localised damage

How to regulate blood flow? Change Energy input Q = ΔPπr 4 8Lη8Lη Change tube diameter

Energy input: Cardiac Output stroke volume = heart rate × Cardiac Output Can be modulated by both endocrine and nervous systems Modulated by nervous activity (via norepinephrine) and circulating epinephrine (=adrenaline) Equation 24.1

Myogenic autoregulation (stretch response) Increased blood flow Increased pressure on arteriole wall Smooth muscle stretched Smooth muscle contracts Increased resistance Decreased blood flow

Neural control of vasoconstriction  Sympathetic nervous system can be activated to induce vasoconstriction Thermoregulation Fight or flight  Mediated by Norepinephrine released by sympathetic neurons

Neural Regulation of vasomotor tone  sympathetic nerves  noradrenaline : smooth muscle   receptors : constriction  : dilation  Relative receptor population density

Smooth Muscle Cell NO Produced Viagra inhibits cGMP breakdown

Endocrine control of vasomotor tone  Epinephrine (Adrenaline) from Adrenal medulla induces vasodilation Fight or flight  Vasopressin (ADH) & Angiotensin II – vasoconstriction  Activate Adrenergic receptors on smooth muscle Not necessarily mediated by nerves

Paracrine control of vasomotor tone  NO Produced by endothelial cells to maintain vasomotor tone in response to hormonal cues Same mechanism as for parasympathetic activation Nitroglycerine  Also responses to local factors indicating hypoxia and damage

 Hormonal Adrenaline (Epinephrine)  receptors  Local Control low O 2, pH, ATP high CO 2, K + dilates vessels locally override neural & hormonal control Fig Local regulation

Reading for Tuesday  Intro to Gas Exchange + breathing in water  pp