1. Dr K’s office hours: In office Tuesdays 2:30 - 3:30 PM `(In office: 3122A Pacific Hall) Group This Friday 11:30 - 12:30 (Meeting room: 3501 Pacific Hall)
2. Dr K’s problem-solving session: Thurs. 5-6 in 3500 Pacific Hall (NOT Wed this week—that’s a holiday).
3. Grading errors? 1. Check the answer key on the web site. 2. Talk to the appropriate TA (see “# graded” below) by Wed, Nov. 11. 3. For all grade changes, turn in a written description of the error(s) to Dr. K, along with exam, by Fri. Nov. 13. ***Dr. K may re-grade the whole exam***
4. Pick up graded exams: If you signed the waiver, outside the elevator of the third floor of Pacific Hall. If you did not sign the waiver, from Dr. K after class or at office hours.
5. TA sections, office hours:
BIPN100 Human Physiology 1 Bill Kristan, Ph.D.
. Section IA # graded Office Hour . Fri 11:00-11:50am SEQUO 148…..Winjet Chou……....(3)…..Wed 3-3:50 pm……...HSS 1145B Fri 12:00-12:50pm SEQUO 147…...Saatchi Patell…….(7)…..Wed 1-1:40 pm……...Muir Woods Fri 1:00-1:50pm WLH 2115 ….. Justine Liang….….(4)…..Tues 10-10:50 am…..Hi Thai Fri 2:00-2:50pm WLH 2206 …….Hao Shi……………(2)…...Fri 3-3:50 pm………...HSS 1128A Mon 9:00-9:50am WLH 2115……. Tim Macaulay....….(8)…...Tues 12:30-1:20 pm…Mandeville Cart Mon 4:00-4:50pm WLH 2208……. Mallorie Nguyen….(6).....Thurs 2-2:50 pm…….Goody's Market Mon 5:00-5:50pm WLH 2208……..Donel Purcella……(5)..…Mon 3:30-4:20 pm…..Price Center East, SR 2 Mon 6:00-6:50pm WLH 2115……...Kyra Rashid………(1)…..Thurs 10-10:40 am…Revelle Com. Lounge
How to interpret ECG recordings
In all cases, “current flow vector” means a depolarization; during repolarization, the recordings have the opposite polarity.
Fig. 14.15(d) of Silverthorn, 6th edition
Normal: ventricular (R) wave largest in lead II
If the heart axis is shifted to the right: the ventricular (R) wave is largest in lead III, and negative in lead I.
From Berne & Levy Physiology, 6th ed., Fig. 16-28
If the heart axis is shifted to the left: the ventricular (R) wave largest in lead I, and negative in lead III
• Caused by hypertrophy (increased thickness) of the right ventricle
• Caused by hypertrophy (increased thickness) of the left ventricle
Uses of ECG: 2. Limb leads can detect changes in thickness of ventricles.
Fig 16-31 in Berne & Levy Physiology, 6th ed.
First-degree: prolonged P-R
Second-degree: drop-out of some QRS complexes
Third-degree (complete): P and QRS independent
Uses of ECG: 3. Can detect conducting system block.
Uses of ECG: 3. Can detect conducting system block.
Silverthorn: Figure 14-23, 5th edition, and Fig. 14.15(h) of 6th edition
Grand summary: Electrical & mechanical events of the cardiac cycle
Silverthorn, 6th edition; Fig. 14.18
lub dub
Effects of Epi, muscle stretch on stroke volume
Cardiac autoregulation (Starling Law of the Heart)
Starling’s Law of the Heart: increased atrial filling (from venous return) increases cardiac output. Cause: cardiac muscle contracts more strongly when stretched.
Plot peak contraction vs. ventricular volume for a number of atrial volumes:
. increased atrial filling
. decreased atrial filling
Starling’s experiment:
Results from Starling’s experiment:
Stro
ke v
olum
e (m
l)
decreased atrial filling: smaller contraction
increased atrial filling: larger contraction
normal filling
....is the same as the first part of the length-tension curve for skeletal muscle
Pea
k of
the
cont
ract
ion
The length-force curve for cardiac muscle....
. increased atrial filling
. decreased atrial filling
....is the same as the first part of the length-tension curve for skeletal muscle
Pea
k of
the
cont
ract
ion
The length-force curve for cardiac muscle....
. increased atrial filling
. decreased atrial filling
500
Effects of Epi, muscle stretch on stroke volume
Ventricular volume
Venous return +
Ventricle
Muscle stretch +
Ventricular muscle
Muscle contraction
+
Ventricular muscle
_
Stroke volume +
Ventricle
As drawn, this is a negative feedback
Here’s Starling’s Law as a feedback diagram:
, but it can be positive feedback.
The length-tension (stretch/contraction) curve for cardiac muscle is complex:
Muscle stretch
Muscle contraction +
Ventricular muscle
At low stretch, it is positive:
Muscle stretch
Muscle contraction _
Ventricular muscle
but at high stretch, it is negative:
Venous return
Ventricular volume
Muscle stretch
Muscle contraction
Stroke volume
+ +
+
_ +
Ventricle Ventricular muscle
Ventricular muscle
Ventricle
This means that Starling’s Law is negative feedback at normal venous return….
Venous return
Ventricular volume
Muscle stretch
Muscle contraction
Stroke volume
+ _
+
_ +
Ventricle Ventricular muscle
Ventricular muscle
Ventricle
but it becomes becomes positive feedback when the venous return is abnormally high:
Lecture 13: Hemodynamics
Leucocytes = white blood cells (WBCs)
Erythrocytes = red blood cells (RBCs)
Serum = plasma with clotting proteins (fibrinogen) removed
Hematocrit = percentage of blood volume that is cellular.
Components of blood
(From Fig. 13.12)
(From Fig. 13.10)
Figure 15-1 Functional model of the cardiovascular system. (Silverthorn, 5th ed)
Control of pressure and flow in the cardiovascular system
The pressure exerted by a fluid drops as it flows through a tube