lecture 31 Flashcards
how trainable is blood volume
very trainable and has big advantages
what does BV =
plasma + red cell volume.
what would increase in plasma volume mean
increase venous return. so, increase SV, increase thermoregulation.
how long does it take for PV to become measurable
takes only 1 day to become clearly measurable.
what would increase in RCV mean
increase oxygen delivery, decrease demand for peripheral blood flow.
how long does it take RCV to be measurable
around 3 weeks.
when does athletic anaemia occur
occurs early in increase training load. usually due to plasma volume increasing faster than red call volume increasing.
what does Haematocrit =
red blood cell volume / blood volume
initial stimulus of blood volume: PV.
acute decrease in BV due to decrease in both central venous pressire and arterial pressure. causing acute increase in osmolality. increase albumin synthesis. which helps create balance increaing PV.
initial stimulus of blood volume: RCV
(renal) hypoxia.
mediator of increase blood volume in PV
aldosterone (conserve sodium and water), ADH (conserve h20)
mediator of increase volume in RCV
erythropoietin
how to stimulate PV for increase in BV
Heat, long duration acticity, dehydration.
how to stimulate RCV in increase of BV.
very prolonged increase PV.
how does vascularisation influence o2 extraction and utilisation
new formation of blood tissues within a blood vessel. vascular resistance changes the diameter of arterioles. more capilarisation around each muscle fibre enhancing oxygen extraction.
how does muscle influence o2 extraction and utilisation.
fibre type and size - smaller muscles have greater surface area. slow twitch fibres are more efficient with o2.
mitchondria - depending on size, no., cellular location and oxidative enzyme concentrations.
myoglobin
what are the key signals for endurance training in the muscle
increase in calcium, increase in AMP/ATP and increase in ROS.
adaptations driven by these muscle signals.
enzyme activity, increase in slow twitch myosin, capillarisation and antioxidant capacity.
main reason for increased systemic vascular capacity in endurance runners
larger arteries and arterioles.
some new networks of arteries and arterioles. more capillaries (angionesis).
how does training increase systemic vascular capacity?
metabolic signals
shear stress in blood vessels
how does exercise put high shear stress on vessel wall.
increase in NO production
increase vessel dilation (NO-dependent dilation)
and stimulates vessel proliferation.
what training is best for increase systemic vascular capacity
wide range of intervals and continuous are effective.
how does capillarisation aid exchnage
↓ diffusion distance
increase time for exchange
increase blood flow in tissue
do bigger fibres need more capilaries?
yes
what type of fibre need more capillaries
oxidative fibres need more.
what does endurance training cuase the size of fibres to be
Endurance training causes hypertrophy of Type I fibres (~30% larger)
what does endurance training cuase the types of fibres to be
Shift in type Type II fibres toward IIa, But probably not Type II to I.
do
do fibres become more oxidative with endurance training ?
All fibres become more oxidative!
how to recruit the type 2 fibres
increase force (size principle)
fartlek training.
↑ Intensity, duration or duty cycle
adaptations in mitochondria volume and function with training
increased quantity of mitochondrial protein
proportional increase in aerobic enzymes (krebs and ETC).
enhanced abilility for aerobic metabolism (CHO anf FATS)
maintenance of cellular homeostatis and po2 gradient
is glycogen sparing in exercise a large effect?
yes large and valuable
why is glycogen sparing a large effect?
metabolise fat, save CHO.
what is glycogen sparing related to and caused by
increase capillarisation and increase mitochondria volume
what does myoglobin do?
ready source of o2 and aid diffusion of o2 from membrane to mitochondria.
