Class Notes (838,786)
Canada (511,086)
Physiology (645)
PSL301H1 (254)
Lecture 11

Lecture 11.docx

4 Pages
89 Views
Unlock Document

Department
Physiology
Course
PSL301H1
Professor
Michelle French
Semester
Winter

Description
Lecture 11  Distribution of Blood  “We move around 5L of blood per minute”  Cardiac Output  Variables that affect Venous Return and End Diastolic Volume  Any change at one level has direct consequences at other levels  I.e. Sympathetic Nervous System  Venoconstriction  Venous Pressure  Venous Return  EDV  Blood Flow  Blood flow through individual blood vessels is determined by vessels resistant to flow  In a closed system, the total volume of input flow equals the total volume of the output flow  In the circularity system, blood is being carried to different organs such as liver and kidneys and they are not all carried by the same size vessels; some maybe under sympathetic nervous stimulation.  When one vessel is constricted, resistance increases and blood flow decreases. Flow from the constricted vessel is redirected to other vessels with lower resistance  Flow is inversely proportional to Resistance  Flow is proportional to Pressure/Resistance - Blood flows when pressure is present  Pressure effects can occur in arterioles, capillaries and veins  Blood pressure throughout the systemic circulation  Blood pressure is the highest in the arteries and decrease continuously as it flow through the circulatory system  Left ventricle contracts, generates pulse; great fluctuation in pressure  Why is there no fluctuation (drop) in the artery? Hence why the Aorta has a thick Tunica Media (elastin and smooth muscle)  Pulse Pressure  Pulse = Systolic – Diastolic  Mean arterial pressure is a function of cardiac output and resistance in the arterioles  Mean Arterial Pressure is proportional to Cardiac Output X Resistance  Elastic Recoil in Arteries  Ventricular Contraction  1) Ventricle contracts  2) Semilunar Valve opens  Aortic valve  3) Aorta and arteries expand and store pressure in elastic walls  Ventricular Relaxation  1) Isovolumic ventricular relaxation  2) Semilunar valve shuts, preventing flow back into ventricles  3) Elastic recoil of arteries send blood forward into rest of circulatory system  Blood Pressure  Blood Pressure = Systolic P – Diastolic P  Average pressure  120/80  = 40 mmHg  Mean arteriol pressure (MAP)  In the cardiac cycle, 2/3 of time, the heart is at rest (diastolic)  MAP = 2/3 diastolic + 1/3 systolic  = 93 mmHg  Pulse  Pulse – pressure wave of circulating blood  Monitored at pressure points where pulse is easily palpated  Measuring Arteriol Blood Pressure  Measured at the Brachial Artery  Korotkoff’s Sound  The “cuff” closes the brachial artery shut. The pressure is released slowly by opening the cuffs valve.  1) The snapping sound first heard at the systolic pressure. Clear tapping, repetitive sounds for at least two consecutive beats is considered the systolic pressure.  2) Murmurs heard for most of the are
More Less

Related notes for PSL301H1

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit