AES 426 Exam 1

Blood flow through heart order

Superior/inferior vena cava, right atrium, tricuspid valve, right ventricle, pulmonary valve/artieries/veins, left atrium, bicuspid valve, left ventricle, aortic valve, aorta, body

Motor unit

an alpha motor unit and all the muscle fibers it innervates

Type I fibers have a ____ motor neuron size, ____ fatigue resistance, ____ force production, and ____ capillary density

small, high, low, high

Which neurotransmitter is released from the alpha motor neuron into the neuromuscular junction and is primarily responsible for initiating a skeletal muscle contraction?

acetylcholine (ACh)

Force development _______ when sarcomeres are too far apart causing fewer cross bridges between actin and myosin to be formed.

decreases

Muscle spindles are found

inside skeletal muscles

Muscle spindles primarily detect

change in length and rate of change in length

Golgi tendon organs (GTOs) are found

within tendons

GTOs detect muscle

tension/force

Where is calcium stored within the skeletal muscle?

sarcoplasmic reticulum

Gluconeogenesis

the creation of glucose from non-carbohydrate sources

Rate-limiting enzyme for the oxidative energy system

isocitrate dehydrogenase

If the applied force is closer to the fulcrum compared to the resistive force, what type of lever is this?

Class III

Where is the Krebs Cycle located within the skeletal muscle cell?

mitochondria

What substrates can be used to generate ATP via the Oxidative Energy System?

fatty acids, amino acids, glycogen, glucose in the form of pyruvate

_________ is the end result of glycolysis

pyruvate

What are the two fates of pyruvate?

1) Converted to lactate (fast glycolysis) or 2) Goes to mitochondria to be converted into Acetyl-CoA and enter the Krebs cycle to make more ATP (slow glycolysis)

Cori cycle

lactate produced by working skeletal muscles gets transported to the liver, converted into glucose, and is sent back to the muscle to use as energy

What is the net number of ATP molecules produced during glycolysis if the system starts with glycogen?

3

The size principle states that

motor units are recruited from smallest to largest as force requirements increase

When the body first requires force to be produced, it recruits smaller motor units with smaller neurons because these are ____ fatigue-resistant.

more

Bioavailable testosterone decreases with age because

more testosterone becomes bound to SHBG (sex hormone-binding globulin)

Why is testosterone not bioavailable when it binds to SHBG?

When it binds to SHBG, it’s less available to enter cells and bind to androgen receptors, so less testosterone is available to produce its effects.

Which steroid hormone is released from the adrenal cortex?

cortisol

Insulin is a polypeptide hormone that induces translocation of the ______ receptor within a muscle cell to help bring glucose into the muscle.

GLUT-4

________ is a polypeptide hormone

insulin

Epinephrine and norepinephrine are released from the

adrenal medulla

Epinephrine and norepinephrine are also known as

catecholamines

With anaerobic training, muscle hypertrophy can occur through increases in the net accretion of the proteins:

actin, myosin, titin, and nebulin

Anaerobic training causes type IIx —> type IIa fiber shifts because

fibers adapt to have better fatigue resistance while maintaining high force/power

Why is there a reduction in mitochondrial density with anaerobic training?

Number of mitochondria doesn’t proportionally increase with increase in muscle volume

Anaerobic training causes adaptations related to _____ production and ______ size rather than adaptations that increase oxidative capacity.

force, muscle

Myoglobin

protein that carries oxygen to mitochondria within muscle tissue

During what age range do most individuals reach peak bone mass?

25-30 years

Given we all have a genetic limit (ceiling or upper limit) regarding aerobic power, why do individuals continue to train if they are near their upper limit?  

slight improvements can be beneficial

Acute aerobic physiological adjustments made at altitude include ________ tidal volume, ______ cardiac output, and ___________.

increased, increased, hyperventilation

Which of the following is synthesized and released in response to low blood oxygen levels and will increased red blood cell production?

erythropoietin (EPO)

A blend of physiological and psychological activation in an individual and refers to the intensity of motivation at any given moment.

arousal

Intrinsic motivation

doing something because you personally enjoy it and find it satisfying

Extrinsic motivation

doing something because of an external reward, consequence, or pressure

Process goal

focuses on what an individual does (ex. practice)

Outcome goal

focuses on an outcome of actions (ex. winning); less individual control

4 types of vertebrae that make up vertebral column

cervical, thoracic, lumbar, sacral

How many vertebrae make up the cervical region?

7

How many vertebrae make up the thoracic region?

12

How many vertebrae make up the lumbar region?

5

How many neuromuscular junctions does a muscle fiber have?

1

A motor unit is the basic functional unit used to

activate muscle fibers and produce force

Steps to excitation-contraction coupling process

1) Motor neuron releases acetylcholine (ACh), 2) Action potential travels down sarcolemma and t-tubules, 3) Calcium is released and exposes binding sites on actin 4) Myosin binds to actin

What two myofilaments need to form a crossbridge for there to be a skeletal muscle contraction?

actin & myosin

Type I fibers are innervated by ______ motor neurons.

small

Type IIa/x fibers are innervated by _____ motor neurons

large

Henneman’s Size Principle says:

motor units are recruited from smallest to largest as force demands increase

Why are type I fibers recruited first during force production?

Because Type I motor units have small motor neurons and therefore have a lower recruitment threshold

Order of recruitment (Henneman’s Size Principle)

I, IIa, IIx

Muscle spindles detect _____ and rate of _____ in length.

stretch, change

Where are muscle spindles located?

within skeletal muscle belly

What are the two types of fibers inside a muscle spindle?

nuclear chain & nuclear bag

What do nuclear bag fibers mainly detect?

change in muscle length

What do nuclear chain fibers mainly detect?

muscle length

Where are GTOs located?

in tendons near the myotendinous junction

GTOs are activated when the tendon is

stretched

What happens to the firing rate of GTOs when tension in the muscle increases?

increases

GTOs are ________ mechanisms.

inhibitory

The right ventricle pumps blood to the _____.

lungs

The right ventricle pumps blood to the ____.

body

What system within the human body extrinsically controls heart rate?

autonomic nervous system

What cranial nerve provides parasympathetic control of heart rate?

Cranial nerve 10 (vagus)

The arterial system carries blood

away from the heart

The venous system carries blood

back to the heart

The primary function of the respiratory system is

exchange of oxygen and carbon dioxide

How is oxygen and carbon dioxide transported throughout the human body?

oxygen binds to hemoglobin, and CO2 is transported as bicarbonate ions in the blood

Agonist

prime mover, the muscle most directly involved in a movement

Antagonist

muscle that slows/stops a movement

Synergist

muscle that assists indirectly in a movement

Biceps curl agonist, synergists, and antagonist

biceps brachii, brachialis/brachioradialis, triceps brachii

Leg extension agonist, synergists, antagonist

quadriceps, biceps femoris (hamstrings)

Mechanical advantage

the ratio of the moment arm through which an applied force acts to that through which a resistive force acts (how much force you get out vs how much force you have to put in)

Mechanical force calculation

Output force (load)/input force (effort)

MA > 1

mechanical advantage

MA < 1

mechanical disadvantage

Mechanical disadvantage

must apply a greater force than the amount of resistive force

In a first class lever, applied and resistive forces

are on opposite sides

1st class levers

can provide mechanical advantage or disadvantage

1st class lever: ______ in the middle

fulcrum

2nd class lever: _______ in the middle

resistance (load)

3rd class lever: ________ in the middle.

effort (muscle force)

The fulcrum/joint matters because the muscle creates force, but the joint determines

how that force gets translated into movement

You can produce less force when further from the fulcrum because

longer distance from fulcrum = greater leverage = less force needed

A system has a mechanical advantage when the muscle can produce the desired movement/overcome the resistance with ____ force than the resistance itself requires.

less

Most muscles operate at a mechanical ___________.

disadvantage

Second class levers operate at a mechanical advantage because the effort is _______ from the fulcrum than the resistance.

farther

Third class levers operate at a mechanical disadvantage because the effort is _______ to the fulcrum than the resistance.

closer

Moment arm

how far the force is effectively acting from the joint

Mechanical advantage moment arm formula

applied force moment arm/resistive force moment arm

Third class levers alwyas operate at a mechanical disadvantage because the applied force (muscle) is always

between the fulcrum and the resistance

Movements in planes ______ the plane itself.

follow

Frontal/coronal plane

divides the body into anterior and posterior sections

Movements in frontal plane

adduction/abduction, elevation/depression

Sagittal plane

divides body into left and right halves