Midterm 2 Flashcards
BMI
weight relative to height
BMI formula
Weight (kg) / Height Squared (m^2)
Designated Obese BMI
> 30
Increased risk of disease BMI
> 25
Crural Index
lower leg relative to upper leg
Brachial index
lower arm relative to upper arm
Androgyny index
shoulders relative to hips
why are children more cold sensitive
they have larger surface area relative to volume
most common model in body composition analyses is the 2 component model of the body which groups all tissues into
Lean Body Mass
Fat Body Mass
Lean Body Mass
includes skeletal muscle, bone, water
Fat body mass
storage fat vs essential fat
storage fat
accumulates as adipose, is an energy reserve, and protects organs
essential fat
bone marrow, heart, lungs, liver, kidneys, spleen, intestines, muscle
female hip shape
gynoid (pear)
male hip shape
android (apple)
gold standard for all methods of body composition calculations
Hydrostatic
archimedes principle
amount of water spilled equals volume in space that body occupies
density =
mass / volume
air displacement has to correct for
air in the lungs (residual volume)
air in the gastrointestinal tract
bioelectric impedence
influenced by hydration level; based on differences between fat free mass and fat mass
Skinfold thickness
% body fat calculations
sum of skinfolds
three types of somatotyping
endomorphy, mesomorphy, ectomorphy
sex difference for somatotypes
males - mesomorphic
females - endomorphic
endomorphic
roundness
mesomorphic
muscularity
ectomorphic
linearity
functional unit of a muscle
sarcomere
muscle contraction (2 points)
sarcomeres shortening
actin sliding over myosin
crossbridge formation
signal comes from motor nerve activating fibre, heads of myosin attach themselves to actin filaments
crossbridge movement
shortening of the sarcomeres, shortening of each sarcomere is additive
outer membrane of a muscle fibre
sarcolemma
if fewer cross bridges form
less muscular tension
net like labyrinth of tubules inside muscle fiber
sarcoplasmic reticulum
connective tissue (3 points)
- composed of collagen
- surrounds all myofibrils, muscle fibres
- continous with tendon that joins muscle to bone
attached to bones to create movement
muscles
strong fibrous tissues that attach muscle to bone
tendons
for muscle to contract, needs a drive mechanism called:
a motor unit / motor endplate
synapses
gaps between adjoining nerves
impulses cross gap (______) to innervate muscle
motor end plate
gaps crossed using neurotransmitter _______
Acetylcholine (Ach)
impulse travels
over the sarcolemma
through t-tubules
causing calcium to be released
slow twitch
contract slowly, fatigue resistant, lower power
fast twitch
contract quickly, fatigue quickly, generates greater force
colours of fibres
fast - white
slow - red
muscle biopsy shows that FT fibres have more:
dense packed myofibrils (Glycogenic)
large diameter
muscle biopsy shows that ST fibres have more:
capillaries (blood vessels, oxidative)
small diameter
Fill in:
_____________ connects to __________ via t-tubules
Sarcoplasmic reticulum
sarcolemma
contractions are driven by neural impulses called
action potentials
when a sarcomere shortens during contraction
concentric
when a sarcomere lengthens contraction
eccentric
5 Steps in muscle contraction
- Acetylcholine released
- Action potential reaches t-tubule
- SR releases Calcium from storage
- Active site exposure, cross-bridging
- Contraction begins
Central NS
brain + spinal cord
Peripheral NS
all neural tissue outside CNS that connects the CNS w/ the rest of the body
cerebral cortex
plans and initiates VOLUNTARY motor activity
cerebellum
coordinates complex motor patterns
medulla
brain stem and spinal cord, simple cranial and spinal reflexes, regulates cardiovascular/respiratory systems
sensory cortex
collects info from various sensors throughout body AND TRANSMITS TO THE BRAIN
motor cortex
conducts signals to activate MUSCLE CONTRACTION (brain to muscle)
efferent impulse
carry signals from motor cortex to muscles
muscle fibre contains _________ made up of _________
myofibrils
contractile proteins