Thanks
No figures availablr.
Lecture: Homeostasis
I. Organization
of Life
A. Structure:Function
and Function:Structure
1. Anatomy - study of the structure
of cells, tissues, organs, organisms
2. Physiology - study of how
cells, tissues, organs, organisms function
3. Darwin - Origin of the Species (1858)
a. Structure
and Function are intimately linked
b. Structure dictates the Function
1.
Finch
beaks and food on the Galapagos
c. Evolution
"selects" most favorable Functions
1.
kidneys/skin of various organisms
a.
kangaroo rat
– desert
b. human – land
c.
sea bass -
salty ocean water
d. Environment
and competition "naturally" select genes that give rise to Structures
that have favorable Functions to improve the viability of each species
B. Organization of Living Things
1. principles of matter/energy (Physics)
2.
atoms -> molecules (Chemistry)
3. complex organic molecules (Biochemistry)
4. organelles -> cells (Cellular
Biology)
5.
tissues (Histology)
6. organs (Physiology/Anatomy)
7. organ/body
systems (Physiology/Anatomy)
8. organism
(Physiology/Anatomy)
*** all fields
overlap and contribute to each other
II. Basic Functions of Organisms
A. Maintenance of Boundaries - separation of organism from
outside world
a. virus
- protein coat around DNA/RNA interior
b. cell - cell membrane
(semipermeable - selective)
c. organism
- skin
B. Movement -
ability to move self and materials
a. cells
- cilia and flagella (sperm)
b. humans - muscle cells
(contractility) & bone
C. Responsiveness
(Irritability) - respond to both Internal and External changes
a. nervous system - quick response to
change
b. endocrine system - medium/longer
changes
D. Digestion
- breaking down foodstuffs to useable/absorbable form
a.
digestive system - breakdown/absorb essential materials
E.
Metabolism - all chemical reactions that occur in
cells & body
a.
anabolism -
synthesizing larger molecules
b. catabolism - breaking down larger molecules
c.
regulated
primarily by endocrine hormones
cellular respiration -
breaking bonds of larger molecules for useable energy currency (ATP)
a. digestive
system - mainly carbohydrate & fats
b. respiratory
system - oxygen and carbon dioxide
c. cardiovascular system - distribution of
nutrients and
gases
glucose
+ oxygen -> carbon dioxide + water + ENERGY (stored in ATP)
F. Excretion
- removing all types of waste from the body
a. digestive system - unused foodstuffs
b. urinary system - nitrogenous wastes
(urea) and electrolyte (salt) balance
c. respiratory system - carbon dioxide
G. Reproduction
- creating more organisms of the same species
a. virus
- depends on cells for their machinery
b. cells
- the process of division (mitosis)
c. human
- sexual (sperm and egg)
i. regulated
by hormones (especially female)
H.
Growth -
increase in size of cell, organ, or organism
a. number of
cells can increase (mitosis)
b. size of cells can increase (fat cells)
III. Basic Biological Needs
of Humans
A. Nutrients
- molecules for structure and energy
1. carbohydrates
- primary energy source & structural
a.
glycogen, sugars (glucose)
2. proteins
- primarily structural & for signaling (hormones and receptors)
a. 20
amino acids are basic building blocks
b. actin
and myosin microfilaments of muscle
c. receptors
for hormones/neurotransmitters
d. neuropeptides (enkephalins of nervous system)
3. fats (lipids) - insulation, energy, structure
a.
major
component of membranes (phospholipids)
b. highest energy content by weight (calories)
4. vitamins - act as cofactors for enzyme
functioning
5. minerals - essential for signaling and structure
a.
nerve signals
- Na+, K+, Ca++, Cl-
b. carry oxygen - Fe+ + in hemoglobin
c.
bone - Ca++, Phosphates
B.
Oxygen - essential for maximum energy gain from food
1. cellular
respiration depends on oxygen
2. nervous
system alone uses 25% of all oxygen in humans
C. Water - essential for cellular
reactions and transport
D. Body Temperature - essential for
cellular reactions
1. most
human enzymes work best at 37°C (98°F)
E. Atmospheric Pressure - for proper absorption of oxygen
Physiology is
the study of how organisms separate self and non-self; move; respond to
internal and external changes; digest, metabolize, and excrete materials;
reproduce; and grow.
This is achieved by maintaining a proper BALANCE
both internally and with the outside world.
IV. Homeostasis
A. Homeostasis - maintaining relative constancy in response to
internal and external changes
- dynamic
process; changing but relatively constant within limits
- concerns
all factors relating to well being of organism (see above)
- regards
maintaining internal environment of body due to internal and external changes
1. Homeostasis
refers especially to maintenance of proper conditions for:
a. oxygen (02)
and carbon dioxide (CO2) levels
b. levels of
nutrients in blood (e.g. glucose)
c. electrolyte
/salt balance and osmotic pressure (fluid levels)
d. acid-base
balance (pH)
e. temperature
f. pressure of
body cavities (especially lungs)
Examples of homeostatic mechanisms:
1. proper nutrient levels in the blood
a. insulin/glucagon
- blood glucose levels
2. proper heart rate and blood pressure
a. adrenaline
- response to stimuli
3. removing wastes from the blood
a.
kidneys -
nitrogenous wastes (urea)
b. respiratory - carbon dioxide
4. maintaining
proper oxygen levels in blood
a.
brain and respiratory - adjust breathing rate
5. body
posture and simple muscular reflexes
a.
nervous system and muscular system
B. General Characteristics of Homeostatic
Control Mechanisms
1. Nervous & Endocrine Systems are general controls
2. Basic
Organization of Control Mechanisms
a. receptor
- monitors internal/external stimuli sends info to control center via afferent
path
b. control
center - analyzes info as it compares to a "set point" for that
particular variable
1. variables may include: glucose level, heart
rate, blood pressure, urea concentration, oxygen level, tension on a muscle.
c.
effector - physiological mechanism
acting from the
control center
via efferent path
C. Negative Feedback Mechanisms
1.
control
mechanism DECREASES intensity of condition to bring back to "set
point"
example: regulation of
glucose levels in blood
a. person eats a candy bar with
lots of sugar
b. glucose levels in the blood
rise rapidly
c. receptors sense
increase in blood sugar
d. control
center calls for reduced blood sugar insulin is
secreted into the blood stream
e. insulin causes effector
cells (liver & muscle) to absorb
glucose and store it as
glycogen
g.
glucose levels return to normal (0.9 mg/ml blood)
D. Positive Feedback Mechanisms
(cascade - like a snowball effect)
1.
control
mechanism INCREASES intensity of condition - causing a "domino"
effect
example:
labor contractions during birth
a. baby rotates into cervix
causing pressure
b. receptors sense
increased muscle tension
c. control center calls
for release of oxytocin, causing
muscles (effectors) to
contract more
d. increased muscle tension
causes receptors to continue
the message to the control
center
e. more oxytocin is released
f. loop continues until baby is
delivered and the stimulus is
no longer present
In Physiology, we study how each of
the organ systems work to provide survival needs of organism and maintain
homeostasis of each of the essential variables
Lecture: Basic Chemistry
I. Matter and
Energy
A. Matter - fundamental building blocks of nature
1. elements -
basic units of matter
B. Energy - capacity to do work (put matter into motion)
1. potential
energy - energy stored in a structure
a.
water stored in a lake uphill
b. chemical
bonds of glucose molecule
2. kinetic
energy - energy in an object in motion
a. water in a
stream - allows mill to grind corn
b. broken glucose bonds -> ATP -> muscles work
3. Forms of
Energy
a. chemical
energy - energy in chemical bonds
i. ATP (adenosine triphosphate) - stores energy
b. electrical
energy - energy of separated charges
i. battery - + pole and - pole separate charge
ii. nervous impulse run just like a battery
c. mechanical
energy - energy of matter in motion
i. bowling ball transfers energy to move pins
ii. muscle motion - ATP -> contraction of muscle
d. electromagnetic energy - energy
traveling in waves (light, X-rays, UV rays)
i.
electromagnetic spectrum - visible light, UV light, radio waves, X-rays
C. First Law of Thermodynamics
1. “Energy can
change from one form to another, but it can never be created or destroyed"
(Total Energy In = Total Energy Out)
examples: Car
Engine vs. Human Body
a. Car
Engine - gasoline used to run motor to move car
Chemical Energy (gas) ---> motion (20%) +
heat (79%) + sound (1%)
b. Human
Body - food used to move body, digest, think, etc. Chemical Energy
(food/glucose) --> physiology (80%) + heat (20%)
II. Organization
of Matter (Atoms - Elements)
A. Atomic Particles
Mass Charge Characteristics
proton 1
+1 defines element
neutron 1 neutral defines isotopes
electron 0 -l determines element
bonding properties
B. Organization
of Periodic Table
1. # protons = atomic number (unique for each element)
2. # protons + # neutrons = atomic mass
3. isotope - same element; different #
neutrons
# protons
+ # neutrons = atomic
mass
Carbon-12 (99%) 6 6 12
Carbon-13
(0.9%) 6 7 13
Carbon-14
(0.1%) 6 8 14
4. # electrons - dictates the NET
CHARGE of an atom
# protons # electrons NET
CHARGE
H 1 1 0
H+ 1 0 +1
H- 1 2 -1
ion – any atom with a positive or negative charge
anion – an ion with a NEGATIVE charge
cation
– an ion with a POSITIVE charge
III. Electron
Shells, the Periodic Table, and Chemical Bonds
A.
Electron
Shells - electrons occupy "shells" as they orbit around the nucleus
(2, 8, 8,..)
B.
The
Periodic Table of Elements is organized by electron shells
H1 He2 SHELL l 2 e-
Li3 Be4 B5
C6 N7 08 F9 Ne10
SHELL2 8 e-
Na11
Mg12 Al13 Si14 P15 S16 Cl17
Ar18 SHELL3 8
e-
C. Chemical Bonds are formed so that each atom can
have the outermost electron shell filled
1. Ionic Bond - one atom donates
electron(s) to another
a.
Example: Sodium Chloride (table salt) Na+Cl-
2. Covalent Bond - two atoms share
one/more electrons
a. Example: Methane (CH4), Carbon
Dioxide (C02), and
Ammonia (NH3)
b. Polar Molecule - electron sharing is
unequal in the bonds
Example: Water (H2O)
c. Non-polar Molecule - electron sharing
is almost equal Example: Methane (CH4)
IV. Elements other than
C, H, O, N in Humans
Primary Elements (3% of all body weight)
Calcium Ca
Bones, teeth, muscle and
nerve action, blood clotting
Phosphorus P Bones and Teeth, DNA, RNA,
ATP. Important in
energy
transfer
Trace Elements (Less than 1 % of body weight
altogether)
Potassium K Osmotic balance; cell voltage,
muscle and nerve
action
Sulfur S
Component of proteins
(cysteine) and other organic
molecules
Sodium
Na Osmotic balance; cell voltage, muscle and nerve
action
Chlorine
Cl Osmotic balance; cell voltage, muscle and nerve
action
Magnesium Mg
Co-factor for many enzymes
Iron Fe
Hemoglobin and many enzymes
Copper Cu
Co-factor of many enzymes
Zinc Zn Co-factor of many enzymes
Manganese Mn Co-factor of many enzymes
Cobalt Co
Co-factor of many enzymes and
vitamin B12
Chromium Cr
Co-factor of many enzymes and
potentiates Insulin
Selenium Se Required for normal liver function
Molybdenum Mo
Co-factor of many enzymes
Flourine F
Teeth and bones
Tin Sn Promotes growth (unknown mechanism)
Silicon Si
Growth, bone mineralization,
connective tissue
synthesis
Vanadium V Promotes growth and reproduction
V. Chemical Reactions
A. Patterns
of Chemical Reactions
1. Chemical
Equation - # of atoms of each element same for reactants and products
C6H1206
+ 602 Ã 6H20
+ 6C02
2.
Synthesis -
smaller molecules form larger molecule
A
+ B Ã AB (anabolic process)
amino
acid 1 + amino acid 2 + ..........Ã peptide
(protein)
sugar
1 + sugar 2 + sugar 3 + ............Ã polysaccharide
(glycogen)
3. Decomposition
- larger molecule broken down into smaller molecules
AB Ã A +
B (catabolic process)
glycogen
---> glucose + glucose + glucose +...........
4. Displacement - one part is
exchanged
AB
+ C Ã A + BC
glucose + adenosine-P- P-P (ATP) Ã
glucose-P + adenosine-P-P
(ADP)
B. Exergonic
vs. Endergonic Reactions
1. Exergonic - energy is released
during the reaction
A +
B Ã C + D +
ENERGY
glucose
+ oxygen ----> water + carbon dioxide +ENERGY (trapped by ATP)
2. Endergonic - energy required for reaction to
proceed
A
+ B
+ ENERGY Ã C
amino
acid 1 + amino acid 2 + ... + ENERGY Ã
peptide (protein)
C. Chemical
Equilibrium
1. Reversible
Reactions
A
+ B Ã AB and AB Ã A + B
2. Chemical Equilibrium
A
+ B ßà AB
D. Rates
of Chemical Reactions
1. size of reactants species (smaller
means faster)
2. temperature
(speeds up the particles)
3. concentration
(more likely to come together)
4. catalysts
(enzymes) - make reacting more convenient
VI. Acid- Base
Chemistry and the pH Scale
A. Water normally exists in an
equilibrium reaction with some dissociation
H2O ßà H+ + OH-
in a
beaker of pure water, the ratio of H+ to H20 is about
1/10,000,000
pH = -log10 [H+] =
-log10 [10-7] = -(-7)
= 7
pH = relative
concentration of H+ in a solution of water
B. Acids - compounds which increase
the concentration of H+ (pH = 1 to 6)
C. Bases - compounds which decrease
the concentration of H+ (pH = 8 to 14)
D. Buffer - compound that prevents
large changes in pH of a solution (pH "shock absorber")
 |
No comments:
Post a Comment
We would appreciate your comments, suggestions and advice