applied anatomy and physiology Flashcards
what is the agonist muscle
it is the muscle for creating movement at a joint, also known as the prime mover.
what is the antagonist muscle?
the muscle that opposes the agonist providing a resistance for coordinated movement.
what is the fixator muscle?
the muscle that contracts to stabilize an area of the body to enable efficient movement.
what are the two types of isotonic contractions?
- concentric
- eccentric
what is concentric contraction?
when the muscle contracts and shortens, reducing the angle between articulating bones at a joint.
what is eccentric contraction?
when the muscle contracts and lengthens, producing tension. this helps to resist forces like gravity to control joint movement.
what is the frontal plane of motion?
divides the body into front and back halves. movements are largely towards or away from the mid line of the body
-abduction or adduction of the shoulder and hip occur in the frontal plane.
e.g star jump
what is the transverse plane of motion?
splits the body into top and bottom parts. the transverse plane is where any form of rotation occurs around the longitudinal axis.
e.g spin in ice skating
what is the sagittal plane of movement?
divides the body into left and right parts down the mid line of the body. largely associated with the flexion and extension of the joints.
e.g knee joint when striking a football
how do skeletal muscles contract?
-action potential conducts the nerve impulse down the axon to the motor end plate
-where the axons motor end plate and the muscle fibre meet is called the neuromuscular junction
-the gap between the end plate and the muscle fibre is known as the synaptic cleft
-once an impulse reaches the end plate it stimulates the vesicle to release ACH which is then secreted across the synaptic cleft
- if ACH is secreted above threshold the action potential will be transmitted into a muscular contraction
- if it doesnt reach threshold, the muscle wont contract
-known as the all or none law
what are slow oxidative muscle fibres designed to do?
they are designed to store oxygen in myoglobin and process the oxygen in the mitochondria to break down fats and glucose into ATP
when are slow oxidative muscle fibres recruited?
they are recruited and provide energy for sub-maximal aerobic work. each fibre will recover quickly and be available for recruitment in just 90 seconds
what is the recovery rate of slow oxidative muscle fibres?
1:1
-work:relief ratio
-fibre damage does not occur with SO, so training can be carried out daily.
what are fast glycolytic muscle fibres designed to do?
they can exert a large force, and have a fast contraction and relaxation time. they are used for explosive, power events.
when are fast glycolytic muscle fibres recruited?
they are recruited in the last 2-20 seconds of contraction- near muscle exhaustion. they work anaerobically and can only last a short duration before fatigue.
what is the recovery rate of fast glycolytic muscle fibres?
work at a 1:3 ratio.
FG fibres are used to exhaustion and take 4-10 days to recover.
what are fast oxidative glycolytic muscle fibres designed to do, and what is a practical example?
structurally designed to produce a large amount of force relatively quickly, but are able to resist fatigue.
e.g. 800m
define myoglobin
a protein in the muscle responsible for transporting oxygen to the mitochondria
what is the pulmonary circuit?
circulation of blood through the pulmonary artery to the lungs (deoxygenated blood) and pulmonary vein back to the heart (oxygenated blood)
what is the systemic circuit?
circulation of blood through the aorta to the body (oxygenated blood) and and vena cava back to the heart (deoxygenated blood)
why is the left side of the heart bigger?
thicker muscular wall which can contract with more force to circulate oxygenated blood from the lungs through the large systemic circuit to the muscles and organs
define conduction system
a set of structures in the cardiac muscle which create and transmit an electrical impulse, forcing the atria and ventricles to contract
how does the conduction system work?
- SA node initiates the impulse which is transported through the atria walls
- the AV node then collects the impulse and delays it briefly, to allow the atria to finish contracting, it then releases the impulse down the bundle of HIS
3.bundle of his then splits into bundle branches and these carry the impulse to the base of each ventricle
4.impulse them reaches the purkinje fibres, where these dispute the impulse through the ventricle walls, causing them to contract
what is cardiac diastole?
the relaxation phase of cardiac muscle, where the chambers fill with blood
what is cardiac systole?
the contraction phase of the cardiac muscle where the blood is ejected into the aorta and pulmonary artery
what occurs during diastole of the atria and ventricle
as the atria and then ventricles relax, they expand drawing blood into the atria
-the pressure in the atria increases opening the AV valves
-blood passively enters the ventricles
-SL valves are closed to prevent the back flow of blood
what occurs during atrial systole?
the atria contact, forcing remaining blood into the ventricles
what occurs during ventricular systole?
-the ventricles contract, increasing the pressure closing the AV valves to prevent back flow into the atria
-SL valves are forced open as blood is ejected from the ventricles into the aorta and pulmonary artery
define heart rate
the number of times the heart beats per minute
-resting value approx 72bpm
define stroke volume
the volume of blood ejected from the left ventricle per beat
-resting value approx 70ml
define cardiac output
the volume of blood ejected from the left ventricle per minute
-resting value approx 5L/min
formula for cardiac output
Q= HR X SV