flashcards
The active binding sites to which myosin cross bridges attach during muscle contraction are found on the
Actin filaments
When a muscle fiber is stimulated by a motor nerve, the muscle fiber either will contact maximally or it will not contract at all.
All or none principle
The structure within skeletal muscle that spreads the nerve impulses rapidly throughout individual myofibrils
T tubules
The muscle that provides most of the force required for a movement
agonist
The specialized network of membranous tubules that stores calcium ions in a muscle fiber
Sarcoplasmic reticulum
The thick filaments of a myofibril are composed mainly of
Myosin
The muscle fiber that constitutes for approximately 50% of the total muscle fibers in most muscles of the body, in the normal, non athletic population.
Type I fibers
A muscle action in which the muscle generates force but does not change in length
Isometric contraction
low oxidative capacity, high glycolytic capacity, fast contraction speed, and a low level of fatigue resistance are characteristics of
Type II fibers
The striated appearance of skeletal muscle fiber is mainly due to the arrangement of
The A-band of a sarcomere contains
Actin and Myosin myofilaments
primary contractile proteins in muscles are
The muscle lengthens as contractile force is generated
Acentric contraction
During a progressive increase in exercise intensity, motor units
with small motor neurons are recruited first
The smallest functional unit of a muscle
Sarcomere
The process by which free fatty acids are broken down to yield multiple molecules of acetyl COA
Beta oxidation
The major source of energy for running a 440 yard race
Carbohydrate
The primary source of energy during a marathon is
Oxidative system
The two enzymes most commonly measured in order to assess the oxidative capacity of muscle tissues are
Succinate dehydrogenase
Citrate synthase
Anaerobic glycolysis begins with either glucose or glycogen and ends with
Lactic acid
The major metabolic waste product that causes the muscles and blood to have a lower ph during exercise of increasing intensity is
Lactate
represents depolarization of the atria
P wave
The volume of blood ejected from the heart with each contraction is called
Stroke volume
SV= ESV-EDV
what phase of the cardiac cycle does the diastolic pressure reflect
Relaxation
Skeletal muscles receive approximately ___% of the total cardiac output under resting conditions, but they can receive as much as ___% cardiac output during heavy endurance exercise.
15, 80
The structures within heart tissue that anchor individual cells together so they do not pull apart during contraction
Desmosomes
The volume of blood in the ventricles at the end of ventricular filling is called
End diastolic volume
Resistance vessels are also called
Arterioles
Represents repolarization of the ventricles
T wave
Represents depolarization of the ventricles
QRS complex
Mean pressure in the pulmonary artery is
15 mmHg
Found in skeletal muscle, serves to transport oxygen from the cell membrane to the mitochondria
Myoglobin
A decrease in muscle or blood ph causes increased unloading of 02 from hemoglobin, this is an example of the
Bohr effect
States that the rate of diffusion through a tissue such as the respiratory membrane is proportional to the surface area and the difference in the partial pressure of gas between the two sides of the tissue
Ficks Law of Diffusion
Regulation of ventilation is complex and regulated by multiple factors. The area responsible for ‘switching off’ inspiration and helping to regulate inspiratory volume is the
Pneumotaxic center
ventilator regulation appears to be most sensitive to which chemical stimuli
pCO2
a shortening of inspiration that occurs in response to activation of stretch receptors in the lungs
Hering Breuer reflex
States that at a constant temperature, pressure and volume are inversely related
Boyles Law
Explains the sum of partial pressures in a mixture of gases
Daltons Law
The amount of air remaining in the lungs after a maximal expiration
Residual volume
The largest volume of air that can be exhaled after a maximal inspiration is
Vital capacity
The carotid bodies are chemoreceptors that are sensitive to changes in arterial
H +, pc02, and p02
The amount of air inhaled or exhaled during a given breath is called the
Tidal volume
An athlete started taking long cycling rides and bought a heart rate watch to monitor HR. She noticed after about 40 minutes of riding at a steady pace that HR gradually increased without increasing the work output. What is causing the cardiovascular drift since cardiac output is unchanged?
decreased SV
Sub maximal exercise tests can be used to estimate aerobic capacity based on
The linear relationship between heart rate and oxygen consumption
Which of the following groups of individuals are most likely to experience exercise-induced hypoxemia during exercise?
Olympic marathoners
what would cause a decrease in stroke volume?
Exercise
An increase in afterload
What is the most important contributor to the improvement in stroke volume with endurance training?
Increase blood volume
Resting stroke volume ____ in the supine position.
Increases
During a graded exercise test, you would expect to see systolic blood pressure ___ while diastolic blood pressure ____.
rise linearly; changes very little
At near-maximal and maximal exercise intensities, ____ is a major determinant of cardiorespiratory endurance capacity.
Stroke volume
The tolerable limits for arterial blood pH extend from
6.9 to 7.5
What type of muscular contraction is mostly likely to induce delayed-onset muscle soreness (DOMS)?
Eccentric contractions
In the trained heart, increased ventricular mass results in ____ EF.
Increased
Heart chamber that undergoes the greatest hypertrophy in response to aerobic training
Left Ventricle
In response to aerobic training, Type 1 fibers become ____ and Type 2 fibers generally _____.
Larger;
No change
Anaerobic 30-second training bouts lead to an increase in
Phosphofructokinase
transport is driven by the energy stored in the concentration gradient of another molecule
Secondary Active transport
molecules are pumped against a concentration at the expense of energy
Primary Active Transport
a substance is transported in same direction as “driver” ion
ex. glucose “piggybacks” onto Na⁺
Co-transport
the minimum charge we need to reach for action potential to happen V sub m
RMP
electrical charge moves towards positive
Na⁺ goes into cell
ex. -70 resting potential to -30
Depolarization
electrical charge moves towards negative
K⁺ leaves the cell
ex. +20 to -40
Repolarization
electrical charge overshoots and goes below the resting potential
ex. -70 to -100
Hyperpolarization
A regenerating depolarization of membrane potential that propagates along an excitable membrane
Action potential
Opening Na⁺ channels generates local current that depolarizes adjacent membrane, opening more Na⁺ channels - how impulse moves across neuron
Propagation
The tendency for turbulent flow increases in direct proportion to the velocity of blood flow, the diameter of the blood vessel, and the density of the blood.
Reynold’s number
Activate and regulate T and B cells. These cells bind antigenic peptides present on MHC II molecules on APC. Make cytokines to coordinate IR.
CD4+ T helper cells
Binds antigens presented by MHC I of virus-infected or tumor cells and kills them. Nearly all nucleated cells display MHC I. These cells also receive an activation signal from helper t-cells.
CD8+ cytotoxic T cells
Virus and infected tumor cells that do not display MHC I or display stress.
NK cells
Mark pathogen for ingestion and destruction by a phagocyte.
Antibody opsonization
Type of APC that present antigens to Cytotoxic T-cells
MHC I
What are the steps of hemostasis or when a blood vessel is ripped open?
- vascular constriction (smooth muscle contracts)
- Platelet Plug
- Blood coagulation
