Invited Guest Speaker: Dr. Tim Gilbertson Nov. 11Thursday11 AMOlin Theater

Sensory Cues for Fat and their Role in Fat Intake

Dr. Gilbertson is Professor & Associate Department Head of Biology and serves as the Associate Director of the Center for Advanced Nutrition at Utah State University. Dr. Gilbertson's research is focused on the investigation of the mechanisms the body uses to recognize nutrients & how this process is regulated by nutritional need. His lab studies the way nutrients including fats, carbohydrates and minerals are detected by chemosensory cells in the oral cavity and in several nutrient-sensitive, post-ingestive organs. The research spans from genes through behavior with expertise in molecular biology, proteomics, electrophysiology, imaging, biochemistry and analysis of behavior.

10 November 2010Cardiovascular Physiology

The Cardiac Cycle

Control of HR and SV

MAP and TPR

Blood Vessels

Lab this week: Frog Heart PhysiologyArrive early if you want to pith.

1QQ # 26 for 8:30 am1.How do action potentials in cardiac myofibers

differ from action potentials in skeletal myofibers?a) Cardiac APs are shorterb) Cardiac APs involve Ca++ influxc) Cardiac APs permit summationd) Cardiac APs do not rely on Na+ influxe) Cardiac APs are conducted from myofiber to myofiber via gap junctions of intercalated disks.

2.As blood passes from the left atrium to the left ventricle, it passes througha) the tricuspid valveb) an atrioventricular valvec) a semilunar valve

1QQ # 26 for 9:30 am1.How do action potentials in cardiac myofibers

differ from action potentials in skeletal myofibers?a) Cardiac APs are longerb) Cardiac APs involve Ca++ influxc) Cardiac APs prevent summationd) Cardiac APs do not rely on Na+ influxe) Cardiac APs are conducted from cell to cell via gap junctions of intercalated disks.

2.As blood passes from the right atrium to the right ventricle, it passes througha) the tricuspid valveb) an atrioventricular valvec) a semilunar valve

Figure 12.14

Pacemaker Cells in

Conducting System:

SA Node andBundle of His

Ectopic Pacemaker

Locations other than SA Node

S 1

Figure 12.22Intrinsic Rate = 100 beat/min

S 2

Figure 12.23

Effect of “Beta blockers”

NE EPI ACh

mAChR

Effect of atropine

Beta-adrenergic receptors

S 3

Figure 12.181st Heart Sound = Closure of Atrioventricular (AV) valves at beginning of Ventricular Systole

2nd Heart Sound = Closure of Semilunar valves at beginning of Ventricular Diastole

S 4

Figure 12.20Systolic

Diastolic

Ejection Fraction = SV/EDV

Atrial Fibrillation

Ventricular Fibrillation & Defibrillation

Stroke Volume

Animation

S 5

Events are same for Cardiac Cycle for Right Side of Heart; only difference is lower systolic pressures in right atrium and right ventricle.

S 6

Frank-Starling Law of the Heart

FS LoH = SV is proportional to EDV

Ventricular Function Curve

Does not depend on hormones or nerves

Assures that the heart adjusts its output based on VENOUS RETURN

Ways to enhance Venous Return:1) muscle contractions2) “respiratory pump”3) venoconstriction

S 7

Who Cares?Heart transplant patients

Fig. 09.21

Low EDV

High EDV

Length-tension “curve” for Cardiac muscle

Overinflation of ventricles leads to less effective pumping

S 8

Overinflation of ventricles results in reduction in stroke volume

S 9

Treatments?…..diuretics

Figure 12.25Contractility

NE from Symp postganglionics & EPI from Adrenal medulla

Note: cardiac myofibers NOT innervated by parasympathetic division

Increase Ejection Fraction

S 10

3 Effects of SympatheticStimulation

1: Increase rate of contraction2: Increase peak tension3: Decrease twitch duration

S 11

Why does this happen?

Control of Stroke Volume

• End diastolic volume (preload)

• Contractility (strength of ventricular contraction due to adrenergic stimulation)

• Pressure in arteries that must be overcome = Afterload

FS LoH

S 12

Afterload is analogous to trying to pump more air into a tire that is already fully inflated (heart contracting to overcome diastolic pressure.)

High blood pressure increases the workload of the heart….. Cardiac hypertrophy….increase chance of irregular conduction of AP through heart

S 13

Hypertrophic cardiomyopathy