PHYSIOLOGY

Vertebrate Physiology• Dr. Kristin Hager

– 334 Jordan Life Sciences– Khager1@nd.edu

• Office Hours– Tuesdays 11:00 AM-1:00 PM– Sign-up sheet outside of Jordan 232

How to do well...• Reading in the textbook ‘Human Physiology’ (D.U.

Silverthorn) is required. Do it BEFORE the lecture.

• Use CourseWare (webfile) for Syllabus, Lectures, Movies:

– CourseWare: CourseWare (sp.11): /afs/nd.edu/courses/bios/bios30344.01

– Lecture PowerPoints for the week will be uploaded every Monday

• Hesburgh reserve readings available for extra help.

Suggested Supplementary Reading Material

•Textbook of medical physiology / Arthur C. Guyton, John E. Hall. 2011.

•Essentials of human anatomy & physiology / Elaine N. Marieb. 2009.

•Human physiology and mechanisms of disease / Arthur C. Guyton and John E. Hall. 1997.

•Human physiology: from cells to systems / Lauralee Sherwood. 2010.

•Review of medical physiology/ William F. Ganong. 2010.

EXAMS• Four exams

– Feb 10– March 10– April 14– Finals week (May 9-13)

• Each exam will contribute 25% of grade.• Material will come from text and lecture.

Copyright © 2009 Pearson Education, Inc.

Levels of organization and the related fields of study

System Organ Tissue Cell

Cardiovascular Heart Myocardium Muscle Cell

Integration between systems of the body

Homeostasis

HomeostasisClaude Bernard (1880’s) ‘constancy of the internal environment’

Walter B. Cannon (1929)Regulation of a ‘relatively constant internal environment’

Physiology is an Integrative Science

HomeostasisSummary

Physiological control systems keep regulated variables within a desired range during homeostasis

Factors underhomeostatic control

• nutrients

• gases

• waste products

• pH

• salt and other electrolytes

• temperature

• volume and pressure

Normal Ranges for Some Blood Values

Arterial pH 7.35-7.45

Bicarbonate 24-28 mEq/L

Sodium 135-145 mEq/L

Calcium 4.5-5.5 mEq/L

Oxygen content 17.2-22 ml/100ml

Urea 12-35 mg/100 ml

Amino acids 3.3-5.1 mg/100ml

Protein 6.5-8 g/100ml

Total lipids 400-800 mg/100ml

Glucose 75-110 mg/100ml

Homeostatic Mechanisms

• Intracellular level• e.g. allosteric modification of enzymes

• Local or Intrinsic level• autoregulation within a tissue

• usually nervous or endocrine systems not required• e.g. dilation of blood vessels in response to CO2

• Reflex control or Extrinsic level• control system is outside the organ or tissue being

influenced

• nervous or endocrine systems involved

Compensating regulatory responses that correct deviations from a stable condition.

Antagonistic homeostatic control of heart rate

Tonic control of blood vessel diameter

Local vs. Reflex Control

Variable toControl

SensorReceptor

IntegratingCenter

Effector

Functions of the Integrator

• Possess a “set point”• Look for error signals• Respond by

controlling the effector

Positive Feedback Systems

• Reproductive hormone cycles in females

• Action potentials in nerve cells

• Uterine contractions during childbirth

NOT always homeostatic

Set-points can be modified

e.g. thermostat in brain hypothalamus (integrator)Increase in set-point for core body temperature during fever

e.g. acclimatization to environmental temperature, altitude (increase red blood cells)

e.g. circadian rhythms

Loop efficiency can be altered

• Frequency

• Speed

• Sensitivity• Anticipation (Feed-Forward Control)

• continual observation

• prediction from other information

• e.g. salivation in response to smell of food

Variable

Receptor

Integrator

Effector

Arterial bloodpressure decrease

Baroreceptordecreases firing

Brainstem

Heart andblood vessels

AfferentPathway

EfferentPathway

Homeostatic control of blood sugar (glucose)

Eating

Increased Blood Glucose

Pancreas Islets of LangerhansBeta cells

Increased Insulin

Cellular Uptake of Glucose

Decreased Blood Glucose

Blood glucose negative feedback loop

Variable

Receptor

Integrator

Effector

Glucose

Pancreasislet beta cells

Pancreasislet beta cells

Body cellsliver, muscle, fat

noneInsulin

Decreased blood glucose

Pancreas alpha cells

Increased glucagon

Increased glucose synthesisIncreased glycogen breakdown

Increased blood glucose

Antagonistic homeostatic control of blood sugar

Decreased blood glucose

Pancreas alpha cells

Increased glucagon

Increased glucose synthesisIncreased glycogen breakdown

Increased blood glucose

Antagonistic homeostatic control of blood sugar

Insulin vs. glucagon