Anatomy and Physiology Sam Rhodes, Ph.D. Professor of Biology What is it?

Anatomy and Physiology

Sam Rhodes, Ph.D.Professor of Biology

What is it?

Anatomy:

Physiology:

Structure and Nomenclature of the Body Parts

Function, Chemistry and Physics of the Body Systems

So what do we expect you to learn in this class (and all college classes)?

1. Learn/memorize specific facts

2. Communicate effectively in writing and orally

3. Use the information you learned to solve problems.

Anatomy and Physiology Are Sciences

• Science relies on empirical evidence. If you can’t measure something then it is out of the realm of science.

• Scientists accept uncertainty. We never know something as “absolutely true.”

• Scientists use controlled experiments and repetitions to reduce uncertainty and increase confidence.

The Scientific Method

Hypothesis: Should attempt to explain what is observed. “Why did the observation happen?”

The Experiment: Produces new empirical evidence that may support or refute the hypothesis.

The hypothesis may have to be refined or completely changed.

The Scientific Method is Comparable to a Court of Law

A crime is committed (observation of fact)

The prosecutor states that the defendant is guilty (hypothesis)

Both lawyers present new evidence (experiments)

The jury examines the evidence and draws a conclusion (the hypothesis is accepted or rejected).

Important Note: just because the jury draws a conclusion doesn’t mean it is correct.

Example of the Scientific Method

The Scientific Community

• Relies on many repetitions to build confidence• Uses controlled experiments

Experimental Condition: the individuals are treated with variable stated in the hypothesis

Control Condition: the individuals are treated exactly like the experimental EXCEPT for the variable in the hypothesis.

• Publishes and distributes results for peer review

What is a theory?• A hypothesis that is supported by

a great deal of experimental evidence from a variety of different sources.

• A hypothesis that has been examined by a large number of different scientists and is accepted as the best explanation for the existing data.

• Only subject to change if new data or a substantially different, and equally valid, explanation is given.

Homeostasis: Central Theme of Physiology

• How do we define homeostasis?• “Maintaining a relatively constant internal

environment, despite changes in the external environment.”

• How does the body maintain homeostasis?• Receptors, Integrator/Controller, Effector,

Feedback.

Receptor: cells that detect a change in a specific physiological parameter

Integrator/Controller: receives input from the receptor and compares the input to an ideal setpoint. If input differs from setpoint, then an efferent signal is sent to an effector.

Effector: tissue or organ that can directly change (increase or decrease) the specific physiological parameter. It directly EFFECTS the parameter.

Feedback: A change in the the specific parameter that is detected by the receptor. “Tells the receptor” that the parameter has changed.

Goal of Glucose Homeostasis

• Glucose is an essential nutrient needed by all tissues.

• Maintain blood glucose close to 100 mg/100 mL

• When glucose levels are low, release glucose from body stores.

• When glucose is high, take glucose out of blood and store in the liver and muscle.

Glucose Homeostasis

Homeostasis of Resting Blood Pressure

• Large blood vessels contain nerve endings that detect when blood pressure is low

• The nerve endings send signals to the “cardiac center” in the brain that compares the information to the normal set-point of blood pressure.

• If blood pressure is too low, the cardiac center will signal the heart to beat at a faster rate.

• The increased heart rate will cause blood pressure to increase.

• The increased blood pressure is detected by the nerve endings in the large arteries.

1. Nerve endings detect thatblood pressure is low.

2. Signal sent to the cardiaccenter in the brain

3. Cardiac center comparesblood pressure to the setpoint.

4. Cardiac center sends signal to increase heart rate.

5. Increased heart ratecauses blood pressure toreturn toward set point.

6. The increased blood pressure provides negative feedback to the nerve endings.

Analysis

• What is the Receptor in the cardiac control system?

• What is the Controller?• What is the Effector?• What is the Negative Feedback?

Understanding the Organization of the Body

Cells: fundamental units of all living organisms. Cells are specialized to specific functions in the body. There is a division of labor. Some cells produce mineral for bone, some cells produce protein for muscle contraction, etc.

Tissues: Tissues are groups of similar cells that function together. There are four major categories of tissues - epithelium (coverings and linings), connective tissue (strength, support), muscle (contraction), and nerve (control and communication).

Organs: Combinations of two or more tissues. The skin is an organ because it is composed of epithelium, connective tissue and small amounts of nerve and muscle.

Organ Systems: Combinations of organs that together serve a general function for the body. For example, the circulatory system pumps blood and carries nutrients, wastes and gases to cells throughout the body.

Introduction to ChemistryThe Study of Changes in Matter.

Gain & Release of Energy

Changes in Physical State (solid, liquid, gas)

Changes in Physical Properties: Elasticity, Density, Color, Smell

The world is made up of 92 naturally occurring substances which can not be reduced to a simpler state by chemical reactions. These substances are called elements.

Important biological elements include:

Carbon: CHydrogen: HOxygen: ONitrogen: NSodium: NaPotassium: KChloride: ClPhosphorous: PSulfur: SCalcium: CaMagnesium: Mg

Each Element Has Unique Physical and Chemical Properties

Carbon: a crumbly, black solid

Magnesium: a shiny, highly reactive metal

Chlorine: A green corrosive gas

When Two Elements React, They Form Compounds That May Have Completely Different Properties

Magnesium Metal

Chlorine Gas

Magnesium ChlorideA white Powder ThatDissolves in Water

Simplified Atomic Structure

All Atoms of the Same Element Have the Same Number of Protons

and Electrons

Radioactive DecaySpontaneous Decomposition of an

Unstable Atom

Alpha Particle = two protons and two neutrons

Beta Particle = electron

Uses of Radioactive Isotopes

Radiation Therapy for Cancer Radioactive Tracers

Chemical Reactions Involve an Exchange of Energy and a Rearrangement of Chemical Bonds.

2 H2 + O2 2 H2 O

H-H H-H O-O O O H H H H

Two hydrogen molecules and one oxygen molecule react to form two water molecules

A hydrogen bond forms when a polar Hydrogen on one molecule is attracted to a partial negative charge (polar) on another atom.