Human A&P 120
Apr. 4, 2008
REVIEW for EXAM #III
Parts you may want
to review from the 1st lectures!
BIOETHICAL PRINCIPLES:
be able to apply to topics discussed in class
A. AUTONOMY – individual choice/freedom Òautonomy of action should
not be subjected to controlling constraint by othersÓ
B. NON-MALEFICENCE: Above all, do no harm – the first medical principle
C. BENEFICENCE--relationship to others not just self; oft cited as the 2nd medical principle
-- 1. basic version: positive obligation
to do good [active]
-- 2. Strong version=PATERNALISM: higher authority enforces
its idea of good
D. JUSTICE--equal or fair treatment, equal rights, equal goods:
-- 1. Egalitarian--equal goods
-- 2. Libertarian--equal
rights/freedoms
Be sure you understand the
basic system, with Antagonistic effector designs and Behaviors as effectors
B. REGULATED
CHANGE--not everything has a constant optimum
1. RESET System: changes the set point of a negative feedback system
2. POSITIVE FEEDBACK System--one which accentuates a change rather than
reducing it. ..it can be useful for
desired rapid changes: e.g., blood
clotting
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1. DELAY PROBLEM: Over and/or Undercompensations! Know how this occurs, as
in delayed BAROREFLEX causing dizziness when you stand up
Solution
= ANTICIPATION system --one which
activates a feedback system before the disturbance changes a regulated state.
May be innate physiology or learned behaviors. Examples--MOTOR CORTEX
activates Cardiovascular and Respiratory centers in the medulla BEFORE blood
gases are disturbed by exercise!
2. NEW-SITUATION PROBLEM: existing feedback system may not work well at high
altitude, with new diet or activity regime, etc.
Solution
= ACCLIMATIZATION or ADAPTATION system:
change effectiveness of feedback component.
Example--EPO boosts
red-blood-cell count at high altitude
II. Principles of EVOLUTION
TWO LEVELS
of EXPLANATION in Biology: see lecture & reading examples
1. "Proximate" or
Mechanistic function = Òhow does it
workÓ analysis
2. Evolutionary or
historical reason= Òwhy did it end up this wayÓ analysis
--Why there are many ILLOGICAL
features, such as choking due to air-food crossover; varicose veins; bad knees
and spinesÉ
REGULATION: III. HORMONES
C. REGULATION: FEEDBACK LOOPS! Effectors = target organs of hormones
2. Neuroendocrine
Hypothalamus/pituitary: often multistage feedback!
Some regulate
body states that can't be properly sensed, so sense & regulate a secondary
hormone!
Growth Hormone example! Know the full feedback system from hypothalamus to body
growth, and abuses/uses of injected HGH!
SELF-SUPPORT & MOVEMENT:
SKELETAL & MUSCLE Systems
Overview: how muscles and skeletons work together
I. SKELETAL -- for body support, protection, AND movement
with muscles; also blood cells
A. Bone General
Features:
--joint
ends with cartilage pad; may be ligaments to other bones
--main
body: spongy bone vs compact
bone=cylindrical arrays of proteins (collagen) and minerals, esp. CaPO4
--marrow produces blood cells: protected site?
--Osteoblasts & osteoclasts-->Constant removal/replacement: in adult, about 4%
per year replaced: keeps bone strong. RULE: most organs continually replaced! not static
-->Self-repairs if
broken: osteoblasts multiply, fill in; osteoclasts dissolve/absorb fragments
B. Bone Specialized Features:
each bone shaped differently for specialized
body function:
--Axial
& Appendicular divisions:
reflect evolution (see below)
Names
to know: see LAB -- SKELETON
exercises
--Types of Joints:
1.
FIBROUS=Immoveable--e.g. teeth; sutures in skull=mainly for protection, not motion
2.
CARTILAGINOUS=Slightly moveable--as in vertebrae: cushioning cartilage discs with gel
core
3.
SYNOVIAL =Freely moveable joints: cartilage pads, synovial
fluid as lubricant
a)
Ball & Socket: arm-shoulder (humerus-scapula) as example: all type
of motions
b)
Hinge: elbow as example
Use as
Effectors for movement:
1) ANTAGONISTIC arrangements: flexor vs. extensor etc. muscles with bones
2) Tendons and Ligaments can act as SPRINGS:
e.g. , how the ARCH of your foot works!!!
3) Leverage with muscles/bones: see LAB!
C.
Bones as a Product of Evolution:
1.
AXIAL: original horizontal
SWIMMING body axis of vertebrates; ancient and modern fish have similar;
adapted well for quadrapedal land animals, but not the best for upright
bidpedal humans; many back problems, e.g. slipped discs
2.
APPENDICULAR: evolved first in
lobe-finned fishes, for digging, walking on seafloor? NEW Fossil fish found
completes the sequence
--same bones
found in all vertebrate limbs: humerus, radius/ulna, wrist/palm, phalanges
(different names in human leg, but evolutionarily equivalent)
HOMINID
EVOLUTION: fossils and genes
provide key evidence--see READING
Hominids:
AustralopithecusˆHomo: know key steps = bipedalism, brain vs. jaw size
Humans
(Homo sapiens) : evidence for
Out-of-Africa hypothesis, approximate dates and genetic relatedness
II. MUSCULAR
System
A. SKELETAL Muscle--actual effectors that move the bones
1. Hierarchical STRUCTURE
a) Organ with tendons, fascia,
nerves
b) Fibers=Cells fused in long arrays,
multinucleated; with Transverse Tubules (TT) & Sarcoplasmic Reticulum (SR)
c) Fibrils=organelles made of sarcomeres
in series
d) Sarcomere=contractile units with
cytoskeleton highly organized
e) Cytoskeletal proteins in
filaments:--THICK filaments = myosin:
motor proteins! Oar-like power-generators
--THIN
filaments = actin--structural; and
tropomyosin + troponins =switch proteins
2.
Contraction/Relaxation Cycle
--RESTING: switch proteins (tropomyosin/troponin)
keep myosin 'heads' from binding to actin
--ACTIVE:
i) Nerve AP arrives at synapse;
NT = acetylcholine, opens fast Na+
channels
ii) Muscle membrane and TTube conduct new AP into the cell/fiber to the SR
iii) SR Ca++
channels open; Ca++ flows into
main cell, binds to switch proteins:
iv) Ca++
binding causes switch proteins (troponins/tropomyosin) to
"flip" out of the way
v) CONTRACTION cycle then begins: myosin heads
use ATP to grab, pull actin filaments
--rowing-like
cycle repeats over and over: power stroke, then recovery stroke. ATP
detaches the myosin head and re-energizes it for the next power stroke
--One-way
system! Muscles cannot actively
expand on their own
vi) RELAXATION ensues after AP gone: Ca++ pumped into
SR, switch proteins flip back to block myosin.
3. Energy: need ATP for i) myosin's detachment and
re-energizing for contraction, and for
ii) SR's Ca-ATPase pumps =
relaxation
REVIEW anaerobic vs aerobic pathways, energy yields from
Exam I!!!
a)
BLOOD/Extrinsic FUEL:
muscles may use GLUCOSE from liver; FATTY ACIDS from adipose
b)
INTRINSIC fuel:
--all muscles, especially "white," load up i) glycogen=glucose polysaccharide; and ii) creatine phosphate (CP) as
back-up to ATP:
--"Red"
muscles load up on fat/triglyceride adipose deposits also nearby ("marbling" in steaks_
USAGE DURING ACTIVITY: local glycogen and CP give first burst of energy, then blood glucose and fats may be used; but this depends on muscle type--see next.
4. Specializations in FIBER TYPES:
|
i)
Fast-Twitch: white color --lots of glycogen (sweeter taste) --few red-colored feature = mitochondria,
capillaries; little fat --use intrinsic CP and glycogen only; give quick ATP production without
oxygen BUT fast fatiguing: WHY??? Inefficient ATP yield
and lactic acid build-up SO: used for "burst" activity e.g. sprint running |
ii)
Slow-Twitch: red color, --lots of adipose stores --lots of mitochondria, capillaries --use extrinsic fats plus glucose from liver, and oxygen; slow to produce ATP but
Long-lasting: WHY?? Limited by delivery; but efficient ATP yield SO: used for long-term activity such as holding posture, hours-long endurance activity |
[iii) Intermediate : pink color; used
for moderate distance running, resistance weight lifting, etc.] |
5. GENETICS: all humans have FAST and SLOW adult myosins on chromosome 17, though regulation of these vary. Also, a SUPERFAST myosin gene is present, used in fast mammals, but is an inactive