lecture day 1 course introduction and embryonic development

BIOL 221        

Course Introduction & Embryonic Development

Course Introduction

Anatomy: Study of body structures

Physiology: study of the function of body structures

How do they work together?

• Form determines function

Levels of Organization:

            Atoms/Molecules – Carbon ©, Oxygen (O), Hydrogen (H), potassium (K), molecules are two or more atom bonded together (CO2, H2O, proteins, lipids, carbohydrates, nucleic acids)

            Organelles – nucleus, ribosomes, ER, golgi body

            Cells – epithelial, nervous (neurons, glial), liver

            Tissue – epithelial, nervous, connective, and muscle

            Organ (made by one or more tissues) – heart (has all 4 tissues), liver, spleen, brain, kidneys

            Organ System (group of organs that work together) – cardiovascular (blood, heart blood vessels), endocrine (pancreas (glucose + glucagon)), digestive (pancreas (digestive enzymes))

            Organism – humans

Homeostasis:

-        Definition: equilibrium or balanced state of the body

-        It is dynamic – temperature (98.6F = 37C)

-        Conditions that are regulated in the body: body temperature, blood pH, O2, CO2, blood pressure, water volume, waste levels, ions

-        Ways homeostasis is maintained:

o   Autoregulation (intrinsic regulation) – cell, tissue, organ regulates their own environment

o   Extrinsic Regulation – cell activities throughout the body are adjusted by nervous (electrical signals) or/and endocrine system (chemical (hormones) signals)

o   Ex. If blood pressure goes down à nervous system increases heart rate and causes vasoconstriction to increase BP or endocrine system will have hormones travel through the blood and increase heart rate and cause vasoconstriction

o   Nervous system – fast response, short lasting (doesn’t need to last long)

o   Endocrine system – longer response, longer lasting (takes time to make the hormone and get it to where it needs to be and then to cause the effect)

-        Feedback Control

o   Controlled condition – variable that is monitored (BP, body temp, gas level, glucose levels)

o   Stimulus - changes the controlled condition (disease or infection, environmental)

o   Receptor – monitors the controlled condition (thermoreceptors, baroreceptors, chemoreceptors)

o   Control center (integration center) – brain and spinal cord, they take the afferent pathway (sensory)

-        Afferent = going in a structure

o   Effector – produce a response to a controlled condition, they use the efferent pathway (motor)

o   Ex. Glands, muscles, adipose tissue

-        Negative Feedback System – reversing the change in a controlled condition

-        Ex. If body temp too high = lower temp

-        If body temp too low = raise temp

o   Examples: everything except 2 that positive feedback

-        Positive Feedback System – strengthen or reinforce a change in controlled condition

o   Examples: blood clotting, childbirth