EP Exam 3

Troponin and Tropomyosin

The two regulatory proteins involved in muscular contraction

Increase in blood volume, heart rate, peripheral resistance

Blood pressure can be increased by:

Efferent

Nerve fibers that conduct impulses away from the central nervous system

Sympathetic and Parasympathetic

The autonomic nervous system can be divided into two functional and anatomical divisions:

Fast Glycolytic Fibers and Fast Twitch Fibers

Type IIx fibers are also called:

Increase in cardiac output and a redistribution of blood flow from inactive tissues to skeletal muscles

In order to meet the increased oxygen demands of muscle during exercise, two major adjustments in blood flow must be made:

Inhibitory transmitters

Neurotransmitters that cause repolarization of membranes are

The number of mitochondria and capillaries surrounding the fiber and the amount of myoglobin within the fiber

The oxidative capacity of a muscle fiber is determined by:

Calcium and ATP is present and action potentials are available

Muscular contraction can be repeated as long as:

Multiple sclerosis

A neurological disease that progressively destroys the mylin sheaths of axons in multiple areas of the CNS

Cell body, dendrites and axon

Neurons can be divided into 3 basic parts:

Length of muscle

Muscle spindles provide sensory information relative to:

Increases as a function of exercise intensity

The arterial-venous oxygen difference:

Increases in the number of mitochondria and capillaries

Following an endurance training program, there is usually a smaller oxygen deficit when the subject does the same work task due to:

Proprioceptors

Receptors that provide the CNS with information about the body position

Atrophy

Loss of muscle mass

50

For the average typical person, once they reach the age of 80 they can expect to lose as much as — % of total muscle mass

Extensibility

Muscle tissue property that allows muscle to stretch without being damaged

Perimysium

Surrounds individual bundles of muscle fibers

Respiratory pump

Predominant factor that promotes venous return to the heart during upright exercise

Arteries and arterioles

Carries blood away from the heart

Left ventricle

Largest and strongest chamber in the human heart

Sarcoplasm

Cytoplasm of a muscle fiber

Sarcolemma

Cell membrane surrounding the muscle fiber

Perimysium

Surrounds individual bundles of muscle fibers

Flexors

Muscles that decrease joint angles

Epimysium

The outermost layer that surrounds the entire muscle

600

The human body contains over —- skeletal muscles

Tendons

Skeletal muscles are attached to bones by:

Dendrites

Conducts impulses toward the cell body

Fascicles

Individual bundles of muscle fibers

Sarcoplasmic reticulum

Storage site for calcium

Motor unit

The motor neuron and all the muscle fibers it innervates

Myosin

Thick filaments composed of protein

Brain and spinal cord

Central nervous system consists of:

Extensors

Muscles that increase joint angles

Endomysium

Surrounds individual muscle fibers

Systemic

— circuit pumps oxygenated blood to the whole body via arteries

Actin

Thin filaments are primarily composed of the protein:

60-100 BPM

The average HR

Epicardium

The layer of the heart that serves as lubricative outer covering

Sinoatrial node

Pacemaker of the heart

Systole

Ventricular depolarization occurs at the beginning of:

120/80

Normal blood pressure

Heart rate x stroke volume

Cardiac output is the product of:

Trained

__ subjects recover faster following exercise since they do not achieve as high a heart rate:

Cardiovascular drift

A decrease in stroke volume and an increase in heart rate:

HR increases, SV decreases and CO stays the same

During prolonged exercise at a constant intensity heart rate, stroke volume, and cardiac output:

Z line, I band, A band, H zone, M line

Parts of a sarcomere:

Central Nervous System (CNS)

Consists of the brain and spinal cord.

Peripheral Nervous System (PNS)

Consists of neurons outside the CNS, with a sensory and motor division.

Sensory Division (PNS)

Also known as afferent fibers, it transmits impulses from receptors to the CNS.

Motor Division (PNS)

Also known as efferent fibers, it transmits impulses from the CNS to effector organs.

Neuron: Cell Body

Contains the nucleus.

Neuron: Dendrites

Conduct impulses toward the cell body; are the receiving end of the neuron.

Neuron: Axon

Carries electrical impulse away from cell body; may be covered by Schwann cells that form a discontinuous myelin sheath, speeding up the electrical impulse.

Synapse

Contact point between axon of one neuron and dendrite of another neuron; includes a small gap (synaptic cleft) between neurons.

Multiple Sclerosis (MS)

Neurological disease that destroys myelin sheaths of axons due to immune attack, resulting in progressive loss of function, with symptoms including fatigue, muscle weakness, and poor motor control.

Neurons as "Excitable Cells"

Exhibit irritability (ability to respond to a stimulus) and conductivity (transmission of the impulse along the axon).

Resting Membrane Potential

Negative charge inside cells at rest (-40 to -75 mv in neurons), maintained by sodium-potassium pump and determined by membrane permeability and ion concentrations.

Action Potential

Occurs when a stimulus depolarizes the neuron, resulting in Na+ influx, followed by rapid K+ efflux; follows the all-or-none law.

Neurotransmitters

Chemical messengers released from presynaptic membrane that bind to postsynaptic receptors, causing depolarization or hyperpolarization.

Synaptic Transmission

Process where neurotransmitters are released from synaptic vesicles, diffuse across the cleft, and bind to receptors.

Excitatory Postsynaptic Potentials (EPSP)

Promote neural depolarization; can be summed either temporally or spatially.

Inhibitory Postsynaptic Potentials (IPSP)

Cause hyperpolarization of the cell, making it harder to depolarize.

Proprioceptors

Receptors that provide the CNS with information about body position, located in joints and muscles.

Kinesthesia

Conscious recognition of the position of body parts and speed of limb movement.

Joint Proprioceptors: Free Nerve Endings

Most abundant type, sensitive to touch and pressure; initially strongly stimulated, then adapt.

Joint Proprioceptors: Golgi-type Receptors

Found in ligaments and joints; functionally similar to free nerve endings.

Joint Proprioceptors: Pacinian Corpuscles

Located in tissues around joints; detect rate of joint rotation.

Muscle Proprioceptors

Provide feedback on changes in muscle length and force development.

Muscle Spindle

Provides information about muscle length and the rate of shortening, responsible for stretch reflex.

Golgi Tendon Organ (GTO)

Monitors force development in muscle, preventing injury; results in relaxation of muscle.

Skeletal Muscle Chemoreceptors

Sensitive to changes in chemical environment, providing feedback on muscle metabolism.

Somatic Motor Function

Motor neurons within spinal cord carry neural messages to skeletal muscles.

Motor Unit

A motor neuron and all the muscle fibers it innervates.

Innervation Ratio

Number of muscle fibers per motor neuron, affecting motor control precision.

Motor Unit Recruitment

Recruitment of additional muscle fibers by activating more motor units.

Size Principle of Motor Unit Recruitment

Smallest motor units are recruited first, followed by larger units.

Vestibular Apparatus

Located in the inner ear, responsible for maintaining balance and equilibrium.

Cerebrum

Involved in organizing complex movements and processing sensory information.

Central Governor Theory of Exercise-Induced Fatigue

Posits that fatigue is regulated to preserve homeostasis by reducing motor output.

Sports-Related Traumatic Brain Injury (TBI)

Resulting from a blow to the head; concussion is mild TBI.

Cerebellum

Coordinates complex movements and incorporates feedback from proprioceptors.

Brain Stem

Includes key structures responsible for cardiorespiratory control and reflexes.

Spinal Tuning

Refines voluntary movement via neural networks in the spinal cord.

Autonomic Nervous System

Regulates homeostasis with involuntary control over smooth muscle, cardiac muscle, and glands.

Sympathetic Division (ANS)

Increases bodily functions during stress; releases norepinephrine.

Parasympathetic Division (ANS)

Slows bodily functions and conserves energy; releases acetylcholine.

Exercise Training and Brain Health

Improves cognitive functions and reduces aging-related decline.

Skeletal Muscle Tissue

Composes 40-50% of body weight and enables voluntary movements.

Smooth Muscle Tissue

Involuntarily controlled muscle found in organs.

Cardiac Muscle Tissue

Found in the heart, involuntarily controlled with striations.

Flexors

Muscles that decrease joint angle.

Extensors

Muscles that increase joint angle.

Skeletal Muscle Properties: Excitability

Ability to respond to electrical stimuli.

Skeletal Muscle Properties: Contractility

Ability to contract in response to stimuli.

Skeletal Muscle Properties: Extensibility

Ability to stretch without damage.

Skeletal Muscle Properties: Elasticity

Ability to return to original length post-stretch.

Sarcolemma

The muscle fiber cell membrane.