Cerrar
When does extrinsic control (i.e. extrinsic to an organ; hormones, neural control) become necessary over intrinsic control?
What effects does the autonomic nervous system anticipatory response have on the body?
In a challenge to homeostasis such as exercise, the autonomic nervous system regulates bodily functions. Sympathetic activity is increased, while parasympathetic activity is decreased. List some effects of increased sympathetic activity.
Muscles (predominately skeletal muscles) convert what percentage of ATP into external work? Where does the remaining percentage go?
Do long-term (e.g. oxidative phosphorylation), intermediate, and short-term energy systems operate separately?
List four initial energy sources from muscle stores available for substrate level phosphorylation.
Why is the energy for prolonged activity dependent on blood flow?
What is lactate converted into when O2 is present?
Metabolic demands of active muscles must be met without compromising the energy supply to which two organs?
The mobilisation of energy stores for activity is primarily under hormonal control - which is the major hormone involved?
Other than glucagon, name two less important regulators of the mobilisation of energy stores in exercise.
List some of the actions of insulin when it is released from the beta cells of the pancreatic islets of Langerhans.
List some of the effects of glucagon when it is released from the alpha cells of the pancreatic islets of Langerhans (in response to decreased plasma glucose, epinephrine secretion, increased plasma amino acids, and increased sympathetic activity).
How does plasma glucose concentration affect the sympathetic nervous system?
How does sex (male/female) influence the use of energy sources?
Give an examine of a local factor to blood vessels, the release of which results in vasodilation.
Up to 20x more blood flow to a muscle can be delivered during activity. What proportion of capillaries in a skeletal muscle vascular bed is open at rest?
List 5 factors which result in vasodilation.
At rest cardiac output is ~5L/min. What are the specific values for CO for males and females?
Under resting conditions, blood flows through pulmonary capillaries in around 1 second and gas exchange is completed by ~1/3 of the capillary. How does this differ during activity?
In elite athletes, at high cardiac outputs, desaturation of haemoglobin can occur. Why?
During exercise, there is increased blood flow to the heart in order for it to work at a higher intensity than at rest. Is this under local or systemic control?
Here is a table of the changes in volumes of blood delivered to different tissues in exercise compared to rest. In marathon runners, the large decrease of 1100 ml/min in light exercise to 300 ml/min in heavy exercise in the splanchnic blood supply is no biggie - but in ultra endurance runners, this can result in the development of ischaemia and tissue damage in the guy as a result of this activity long term.
Vasodilation leads to an increase in the number of capillaries carrying blood through muscles. What does this mean for O2 and mitochondria?
In a haemaglobin-oxygen dissociation curve (in which pO2 is plotted on the x axis and %O2 saturation of haemaglobin is plotted on the y axis), what effect would increasing pCO2/decreasing pH have?
What is Starling's law?
Why is the baroreceptor reflex for controlling blood pressure not active during exercise?
What is the primary mechanism for controlling the mean arterial blood pressure in exercise?
Why does pulse pressure increase in exercise?
Why is it good to have a lower resting heart rate?
If Mean Arterial Blood Pressure = Cardiac Output x Total Peripheral Resistance, an increase in cardiac output leads to an increase in mean arterial blood pressure when...?
If Mean Arterial Blood Pressure = Cardiac Output x Total Peripheral Resistance, a constant cardiac output leads to an increase in mean arterial blood pressure when...?
Here's a table of some cardiovascular changes during exercise. Systolic blood pressure tends to increase more significantly than diastolic pressure (given that less diastolic pressure is needed and vasodilation limits it anyway). There is a bigger difference between arterial O2 and venous O2 the higher the exercise intensity.
Increased gas exchange is required in exercise. How does one increase ventilation?
In order to increase ventilation (either by increasing tidal volume or frequency), what changes are required?
You cannot train your lungs in order to increase efficiency during exercise. What can you train to affect ventilation?
In submaximal exercise, arterial O2 and CO2 concentrations are kept relatively constant. How?
All pulmonary capillaries are recruited for gas exchange when cardiac output exceeds how many times the resting value?
During maximal exercise, how does hyperventilation result?
What is the ventilatory threshold?
What is an incremental activity exercise?
In sprint/power events, the relationship between physiological measures and the performance is poor. However, in endurance athletes performance correlates well with two physiological measures. What are these?
At the highest levels of exercise intensity, O2 consumption begins to reach a...
VO2-max relates to both the O2 supply (maximum cardiac output) and O2 use by the muscles (arteriovenous O2 difference). What is the equation to show this relationship?
In which units is VO2 max usually expressed?
