lecture 1- overview

Question 1

definition of physiology

Answer 1

the study of the function of living processes

Question 2

name the 3 central themes of mammalian physiology

Answer 2

1- evolution/natural selection
2- form follows function
3- regulation (homeostasis via negative feedback)- constant internal state

Question 3

describe negative feedback

Answer 3

stimulus received by sensor, sensor exerts control and activates effector which gives response and counteracts the stimulus

• regulation of blood glucose is negative feedback –> after high glucose meal, blood glucose goes up and activates pancreas which secretes insulin –> uptake of glucose into liver to store as glycogen

Question 4

99% of mammalian bodies are made of 4 elements:
why?

Answer 4

C, O, N, H - b/c they have 2 or fewer electron shells, this allows them to form covalent bonds (long chains) with themselves and with each other

Complexity! get complexity from millions of simple building blocks being put together in complex arrangements

Question 5

give a few examples of the complexity theme

Answer 5

1- amino acids (put together through peptide bonds form long chains of AA’s –> proteins)
2- glucose –> glycogen used for storage
3- glycerol

Question 6

describe electron shells of oxygen

Answer 6

oxygen has 2 electron shells
outer shell has 6 electrons
inner shell has 2 electrons
electrons are not shared equally

Question 7

describe the polar covalent bond of water

Answer 7

water has polar covalent bond- electrons not shared equally, electrons spend more time in the orbit of one atom than the other

• oxygen has greater electronegativity (stronger affinity, attraction) than hydrogen, so electrons spend more time in the orbital of oxygen (partial negative charge on the oxygen)

Question 8

why is water polar?

Answer 8

b/c of the polar covalent bond

polarity is the unequal distribution of charge
polarity across membranes

Question 9

describe what happens when multiple water molecules come together

Answer 9

the hydrogens of one water molecule line up with the oxygen of another water molecule (opposite charges attract)

• hydrogen bonds hold them together (hydrogens of one with oxygen of another)- tetrahedral structure

Question 10

describe properties of water

Answer 10

b/c of hydrogen bonds, water has higher melting point, higher point of vaporization and boiling point, and higher surface tension

• water is a near universal biological solvent

Question 11

what is a electrolyte

Answer 11

a substance that will dissociate 100% into its charged ionic species in water
ex: NaCl (dissociate into sodium & chloride)

Question 12

___ dissolves all electrolytes, which are ___..

Answer 12

water
salts, acids, bases

Question 13

layers of water molecules form what when with electrolytes…

Answer 13

hydration shells due to the fact that positively charged sodium attract negatively charged oxygen (same with negative chlorides and positive hydrogens)

• these hydration shells act as electrical insulation - prevent sodium and chloride from coming back together

Question 14

describe non-electrolytes

Answer 14

do not dissociate 100% into their charged ions, only partially dissociates (called polar non electrolytes)

• ex: amino acid- happens at pH ~7.4, negative charge on carboxyl group and leaves partial positive charge on amino group (nitrogen)- allows for formation of hydration shells

Question 15

describe hydration shells with glucose

Answer 15

hydration shells form around hydroxyls of glucose (small organic molecules that are not electrolytes can still have partial charges)

Question 16

define polarity

Answer 16

the unequal distribution of charge