Lecture Exam 1 - Brain and Contraction Flashcards
What does the Cerebrum contain
Motor Cortex and Sensory Cortex
What is the main part of the brain
Cerebrum
What are the functions of the Cerebrum (5)
- Higher mental processes
- Movement
- Visceral functions
- Perception
- Behavioural reactions
What is the Cerebrum responsible for
The association and integration of the functions
What does the motor cortex consist of
Primary motor cortex
Pre motor cortex
What does the Primary cortex do and where is it
Anterior to central sulcus
Conscious motor movements = pyramidal system
What does the Pre motor cortex do and where is it
Anterior to primary motor cortex
Unconscious fine tuning of muscle activity, balance and muscle tone
What does the pre motor cortex cause to happen
Where does this then happen
general patterns of movement involving groups of muscles that perform specific functions
Basal ganglia and thalamus
What does the Sensory cortex do and where is it
Lies posterior to central sulcus
Relays information through sensory receptors to the motor cortex
What is the Basal Ganglia
What does it do
Cluster of cell bodies that make up the central gray matter of the cerebral hemispheres
Muscle tone and control of movement
What happens if the basal ganglia gets damage
Paralysis/jerky involuntary movement
What does the Thalamus do
relay station of sensory input as well as interpretation of some sensory input
Pain, temp, crude pressure and touch
What does the hypothalamus do (7)
releases hormones (and inhibits them) to control:
- water
- balance
- sleep
- temp
- hunger
- visceral activities
What does the cerebellum do
Coordination of movement
What does the Medulla Oblongata do (6)
Controls:
- Heart rate
- Blood flow
- Equilibrium
- Swallowing
- Salivation
- Respiration
Where do the pyramidal tracts cross over
Medulla Oblongata
What does the medulla oblongata contain
Ascending and descending communication tracts for spinal cord and other parts of the body
What does the pons control and what else does it do (7)
Respiration
- Acts as a bridge between spinal cord
- Responsible for eye movement
- Facial expressions
- Taste
- Salivation
- Equilibrium
What does the Midbrain do
What does it regulate
Sends sensation of:
Touch
Proprioception
Vibrations
To the thalamus
Regulation of pupil size, eye movement and lens shape
Motor tracts in the pyramidal system
- originate in
- % cross over
- Synapse with
- Primary motor cortex
- 90% X over
- Motor neurons in the anterior gray horn of spinal cord to innervate muscles involved in specific movement
What is Ipselateral training and which system does it occur in
One side of the body is developed through training
Will be some cross over effect as neural stimulation occurs on the opposite side of the body
Pyramidal system
What happens in the Extrapyramidal system
- Motor tracts
- Type of movement
- Originates
- Movement patterns
- Synapse with
- Motor tracts do not cross
- Fine tuning of highly skilled movements
- Originates in premotor cortex
- General movement patterns like muscle tone, posture, vision, hearing, equilibrium and control of head movement
- Do not synapse directly with motor neurons
What does the limbic system provide
input to motor cortex due to motivation drive and needs
What are the different sensory receptors (5)
- Muscle spindles
- Golgi tendon organs
- Proprioceptors
- Joint receptors
- Kinesthetic awareness
What are the functions of muscle spindles (3)
Where are they located
- Sense length of fibers
- Reflex contraction
- Coactivation
In between in between intrafusal fibers
What do golgi tendon organs do (3)
Where are they located
- Reflex inhibition for protection of the muscles
- Facilitate recruitment of additional motor units to maintain force production
- help to equalise contractile forces of separate muscle fiber
Insert to bone
Function at spinal cord not all the way to brain
What do proprioceptors do
What do they regulate and facilitate
sense position, length, pressure, tension and temperature in a muscle
regulates change in length and facilitate kinesthetic awareness
What do joint receptors do
Where does this occur and what does it facilitate
Proprioceptors for feedback
Sensory cortex and facilitate kinesthetic awareness
What does kinesthetic awareness involve (3)
Deformation/compression
Acceleration/deceleration
Space awareness
What are Krause
Receptors for cold stimuli
What are pacinian corpuscles
detect changes in vibrations
What are Ruffini corpuscles
detect changes in temperature
What are the two main components of muscle spindles
Intrafusal fibers
Extrafusal muscle fibers
What do intrafusal fibers do
What are they activated by
What senses the change in intrafusal fibers
information is sent back to the spinal cord via
gross muscle contraction
Gamma motor neurons
Annulospiral endings
Sensory afferent neurons
Extrafusal muscle fibers are innervated by
Alpha motor neurons
What is a motor unit
A neuron and all the muscle fibers it innervates
A neuron is
a nerve cell
Soma is
cell body of neuron
Schwann cell is
Responsible for the production of myelin
Synaptic vesicles store
Neurotransmitters
Node of ranvier is where
Because
Salutatory conduction occurs
not covered by myelinated sheath
What happens during an action potential
Na gates open
Influx of Na
Stimulates electrical current (AP)
What is a synapse
point of contact where the nerve impulses are transmitted from one neuron to another
What is the size principle
Motor units with smaller cell bodies are generally recruited first since larger motor units require more stimulation
At rest
What are actin and myosin
Where is ATP bound
Where is CA stored
Separate
Bound to cross bridge
CA stored in SR
Steps of excitation
Voluntary movement from Primary Motor Cortex
Stimulation causes CA to bind to troponin to inhibit the effects of seperating actin and myosin
Steps of contraction
Actin slides over myosin
Coupling activiates myosin ATPase which breaks down ATP to cause a power stroke
Steps of Recharging
New ATP molecule binds to the cross bridge causing myosin to uncouple with actin
New coupling with different actin then occurs
Steps of relaxation
No more neural stimulation
Ca returns to the SR
Myosin ATPase is turned off
Sarcolemma is where
ACh binds to receptors to open Na channels to depolarise cell
Epimysium is
Inserts where
Connective tissue = Muscle belly
Inserts into tendon and surrounds muscle
Perimysium is
Connective tissue = Fasicles
Endomysium is
Connective tissue = Muscle fiber
Sarcoplasmic reticulum (SR) is
What does it contain
Cytoplasm of muscle
Contains sarcomere
Where anaerobic metabolism occurs
What does the S-1 unit head of myosin attach to
What does it change
Actin
Changes its orientation to 45 degrees axis
What does “the tilt” refer to
What is released
Power stroke for muscle contraction
ATPase breaks down ATP to release ADP and Pi
What does tropomyosin do
Blocks actin and myosin from forming cross bridges
What causes tropomyosin to move out of the way
Ca binds to troponin which causes a conformational change
What are the two roles of Ca
Influx of Ca into axon terminal stimulates release of ACh
Binds with troponin to move tropomyosin out of the way
What are the roles of ATP (3)
Energy for power stroke of S-1 myosin head - leads to sliding filament
A new molecule of ATP binds to myosin S-1 head to cause dissociation of actin/myosin - when broken down myosin head moves back away from actin
ATP used to actively pump Ca back into the SR through longitudinal tubules when nerve stimulation stops
What does the Z lines do
keeps actin around myosin
Provides a pathway for AP to travel down t-tubule
Initiates pulling mechanism
What does the M line do
Holds myosin in place
What does the I band do
What is it
Shortens during contraction
Actin only
What happens to the H zone
What is it
Disappears during contraction
Myosin only
What is the sarcomere
What is it from
Contracting unit of muscle cell
Z line to Z line
How fast can a muscle twitch
120 m/s
What is the SR triad
What does it do
What does training do
2 cisternae and t-tubule
Cisternae store Ca
Increases from 5% to 12%
What is the anaerobic enzyme
Myosin ATPase
What is the aerobic enzyme
SDH staining
There is high levels of Myosin ATPase in what muscle fibre
Fast twitch
There is high levels of SDH staining in what muscle fibre
Oxidative muscle
Dark myosin ATPase means it is
Fast
Dark SDH staining means it is
High oxidative
Slow twitch is
Acid…
Basic…
Acid stabile
Basic labile
Fast twitch is
Acid…
Basic…
Acid labile
Basic stabile
FOG is
Acid…
Basic…
Acid labile
Basic stabile
IIc twitch fibres are…
In adults
In children
Stability at all levels
Renovation or training in adults
Undifferentiated fibres in children - become FT or ST eventually
What are the 3 fundamental properties of exercise physiology
Max tension is dependent on actin and myosin binding
Speed of contraction is dependent on the size of axon and the concentration of myosin ATPase
Endurance is based on the ability to recycle or regenerate ATP
What are the 3 motor unit characteristics
Homogeneous - all ST etc
Differs in sensitivity to stimulation
Operates on all or none response
What muscle fibre type has the easiest sensitivity
SO
What is the all or none response
All fibres in one unit have the same sensitivity and contract all at the same time
What are the determinants of force production
Actin/myosin binding **
Number of fibres in active motor unit (increase = hyperplasia)
Number of motor units activated - balance between stimulation and inhibition
Frequency of impulses
Fusiform run….
They have
Parallel running length
Have greater range of movement
Longer muscle fibres
Less strength and resistance to pull
Greater injury risk
Penniform run…
They have…
Run diagnosed to direction of pull
Have poor range of movement
Shorter muscle fibres
More strength and resistance to pull
Less injury risk
What formations cause Fatigue effects on force production
What do these formations do
Formation of ketone bodies and lactic acid
Decrease pH - causes interference with Ca release, actin/myosin binding, ATP breakdown, less ATPase activity
What happens with local muscle fatigue
Decrease in torque
Then neural fatigue - depletion of neurotransmitter
What are the determinants of speed production
Size of axon - myelination
Myosin ATPase
Fibre type being used - increase FT = increase speed
Increase force vs decrease resistance - Increase acceleration = increase force/decrease mass
Coordination - synchronised recruitment
What causes force to increase
Hyper trophy
Hyperplasia
Increase motor unit recruitment
Pre stretch muscle
Fibre type change - strength training = Increase FT
What are the training influences on contractile forces (similar to other flash card)
Hyper trophy
Hyperplasia
Reduced neural inhibition
Strength training - increase FT area
Increase phosphagen stores
Does strength help endurance
Does endurance help strength
Yes
No
Phosphagen metabolism has…
Located in…
Enzymes…
Substrates…
Byproducts…
The highest power
Lowest capacity
Sarcoplasm
Myosin ATPase, CPK, AK
ATP and CP
ADP, AMP, Pi
Anaerobic glycolysis has…
Located in…
Enzymes…
Substrates…
Byproducts…
2nd power
3rd in capacity
Sarcoplasm
PFK, PK, HK (M-LDH), Phosphorylase (H-LDH), Citrate
CHO, glucose, glycogen
Lactic acid and alanine to liver
Phosphagen metabolism happens in the…
First 30 seconds of high intensity
How do you increase the capacity of phosphagen metabolism
Increase:
Creatine
Muscle mass
Training
Power =
How quick you can make ATP
Capacity =
Total kCal you can get from the energy systems
Anaerobic glycolysis occurs from…
Yields how much ATP…
30secs - 3/4min
2 net ATP
What does citrate do in the anaerobic glycolysis
Inhibits PFK - spares CHO to prime the pump for fat usage
How do you increase the capacity of the anaerobic glycolysis
Increase: Training H-LDH Muscle mass Alanine tranominase
Decrease:
M-LDH
What does H-LDH do
What does M-LDH do
Clears lactic acid
Forms lactic acid
Aerobic glycolysis has…
Located in…
Enzymes…
Substrates…
Byproducts…
3rd in power
2nd in capacity
Starts in sarcoplasm, ends in mitochondria
CS, SDH, IDH
Glucose and glycogen
Co2 and h2o
Aerobic glycolysis happens…
Yields how much ATP…
3/4mins - 2/3 hours of moderate intensity
36 in skeletal muscle - sarcoplasm can’t take in NADH + H
38 in cardiac muscle - 8 = sarcoplasm, 30 = mitochondria
How do you increase the capacity of aerobic respiration
Increase:
Training
CH6 loading - increase glycogen
CHO ingestion
What type substances enter the kerbs cycle
Acetyl COA
Oxaloacetate
Beta oxidation has…
Located in…
Enzymes…
Substrates…
Starting products…
Byproducts…
Highest capacity
Lowest Power
Mitochondria
Lipase, Thiokinase, Thiolase, Fatty acyl CoA, Camitine fatty acid transferase
Triglycerides
Acyl CoA and glycerol in liver
Ketone bodies = Decrease pH
When does Beta oxidation occur
Yield of ATP…
During continuous low intensity exercise
100-150 ATP
What is ATP generated from in Beta Oxidation
What is needed to increase the capacity of Beta Oxidation
Acetyl CoA, pyruvate, glucose in liver
More CHO
What are the substrates of ETS
Where does it occur
NAD + H = 3 ATP (cardiac muscle, Krebs, beta, pyruvate to Acetyl CoA)
FAD + H = 2 ATP (Skeletal muscle, krebs, beta)
Occurs in the inner mitochondria membrane for oxidation
What are cytochromes
What do they act as
Act like enzymes to speed things up
They are carriers of H+ and E- in the ETS
What are the starting products and by products of the ETS
O2
H2O
Stages of Priming the Pump
CHO to Pyruvate
Pyruvate to Oxaloacetate
Ocaloacetate combines with Acetyl CoA from fat to form Citrate
Citrate inhibits PFK
Stages of Glycogen sparing
Citrate inhibits PFK to spare glycogen
Forms oxaloacetate = priming the pump
Hitting the wall refers to
No CHO left to access fat for energy
Ketone bodies form = decrease force production because of fatigue
What is Acetyl CoA
Common entry molecule for fat and carbohydrates to enter the krebs cycle
of Acetyl CoA formed from a triglyceride = #of carbons / 2
What does Fat yield
What does CHO yield
9 Kcal/GM
4 Kcal/GM
What are the 4 fates of pyruvate
- Lactate (anaerobic)
- Alanine (anaerobic)
- Acetyl CoA (aerobic)
- Oxaloacetate (aerobic)
What does Alanine act as
What does it minimise
What is it converted back into
Acts as a temporary reservoir for the excessive breakdown of carbohydrates under anaerobic conditions
Minimises the formation of lactate
Converted back into glucose in the liver
What is PFK inhibited by
What is it stimulated by
High levels of phosphagens, hydrogen ion concentration from excess lactate formation, Citrate for glycogen sparing
ADP, AMP + Pi
What is HK inhibited by
What is it stimulated by
High levels of G - G - P
Insulin
What is Phosphorylase inhibited by
What is it stimulated by
High levels of G - G - P
Calcium, AMP and Epinephrine
What are the 6 hormones that stimulate HSL for mobilisation of fat
What inhibits HSL
TSH - thyroxine
ACTH - Cortisol
Growth hormone
Glucagon
Epinephrine
Norepinephrine
Insulin inhibits HSL
What does caffeine stimulate
HSL and Fat mobilisation
Phosphorlyse in glycolysis
Glycogen mobilisation
What is the best load program for CHO
What does it increase
Long hard exercise with mixed diet - 90mins
Then low CHO diet
Then High Carb diet
Ingestion of carb fluids during exercise - increases muscle glycogen
Increases:
Capacity for Aerobic glycolysis
Capacity for Beta oxidation
What occurs from creatine ingestion
Where can you access it from
Increase CP = Increases ATP
Hypertrophy
Protein synthesis
From raw meat and powder
What does sodium bicarbonate do for you
What type of performance does it help with
Increases lactic acid tolerance and capacity of anaerobic glycolysis
Helps with performance in high intensity short duration exercise
What does endurance training do on:
Phospagens
Increase in 25% ATP
Increase in 40% CP
Increase in capacity
What does endurance training do on:
Glycolysis
80 - 100% increase in PFK
Increase in H-:LDH
Decrease in M-LDH (Increase alanine transaminase)
INCREASE IN LACTIC ACID TOLERANCE
INCREASE IN CAPACITY OF ANAEROBIC GLYCOLYSIS - POWER
What does endurance training do on:
Oxidative
Increase in power of CHO and fat oxidation
Increase in myoglobin (O2 delivery)
Increase 200% in muscle mitochondria
Increase in Krebs cycle/ beta enzymes and cytochromes
Increase 100% in lipase activity = Increase capacity of aerobic glycolysis and beta oxidation
Increase in capillary fiber CO2 delivery
What does endurance training do on:
Children
Increase Capacity phospagens
Increase Power glycolysis
What does the A band do
Where muscle contraction happens via sliding filament
What is Saltatory conduction
Faster propogation of action potentials between node of ranvier
Order of muscle structure
Muscle
Muscle fiber (cell)
Myofibrils
Myofilaments
What happens during contraction to:
I band
H zone
A band
Shorten
Shorten
Does not change
Max tension is dependent on
What fiber type is better
Actin - myosin binding
FT > ST
Speed of contraction is dependent on
What fiber type is better
Size of axon
Myosin ATPase
FT > ST
Continuation of muscle contraction is dependent on
What fiber type is better
Ability to regenerate ATP
ST > FT
Do muscle fiber types vary in:
Men and women
Individuals
Parts of the body
No - genetics is not a factor between fiber types
Yes - some people are born with more or less FT or ST
Yes - varies in different muscles
Sprint interval training causes
FT to increase
ST to decrease
Conversion of ST to FT
Endurance training causes
ST to increase
FT to decrease
Conversion of FT to ST
What volume and intensity of training is required to:
Increase hypertrophy
Increase hyperplasia
Reduce neural inhibition
Increase Phosphagen stores
High volume, Low intensity
Low volume, High intensity
Low volume, Low intensity
All types of training
The addition of Strength training to an endurance program will
The addition of endurance training to a strength program
Increase time to exhaustion during submax workload
May reduce the potential strength from strength training if:
- Same muscles used in both trainings
- strength training is more than 3 times a week
