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
what is bradycardia?
a resting heart rate of below 60bpm
what is sub-maximal exercise?
a low to moderate intensity of exercise within a performers aerobic capacity
what is maximal exercise?
a high intensity of exercise above a performers aerobic capacity, that will include fatigue
formula to calculate a persons max heart rate?
220-age
what is a persons heart rate response to exercise?
-an initial anticipatory rise in HR prior to exercise due to the release of adrenaline
-at the start of exercise there is then a rapid increase in HR to increase blood flow and oxygen delivery in line with exercise intensity
-HR then remains steady throughout sustained intensity exercise as oxygen demand is met
-initial rapid decrease in HR as recovery is entered and the action of the muscle pump decreases
-a more gradual decrease in HR to resting levels
how is stroke volume able to increase during exercise
- increased venous return, this is the volume of blood that returns from the body back to the heart. during exercise, vr increases meaning there is a greater volume of blood being returned to the heart and filling the ventricles.
- the frank-starling mechanism, shows us how SV is dependent on venous return. an increased volume of blood returning to the heart leads to an increased end diastolic volume in the ventricles and therefore a greater stretch on the ventricle walls. this greater stretch increases the the force of ventricular contraction allowing more blood to be ejected from the ventricles.
why does stroke volume reach a plateau during sub-maximal intensity
increased heart rate towards maximal intensities does not allow enough time for the ventricles to completely fill with blood in the diastolic phase. this limits the frank starling law
what is the resting heart rate of a trained and untrained performer
untrained= 72bpm
trained= 50bpm
what is the resting stroke volume of a trained and untrained athlete
untrained= 70ml
trained= 100ml
what controls a persons heart rate
the cardiac control centre which receives information from the sensory nerves and sends directions through motor nerves to change HR
what are the three control mechanisms that send information to the CCC
- neural control
- intrinsic control
- hormonal control
how does neural control determine the action of the CCC
-chemoreceptors (located in the muscles, aorta and carotid arteries) detect chemical changes in the blood stream, such as increased levels of carbon dioxide or lactic acid
-proprioceptors (located in the muscles, tendons and joints) inform the ccc of motor activity
-baroreceptors (located in the blood vessel walls) inform the ccc of increased blood pressure
how does intrinsic control determine the action of CCC
-temperature changes will affect the viscosity of the blood and speed of the nerve impulse transmission
-venous return changes will affect the stretch in the ventricle walls, force of ventricular contraction and therefore stroke volume
how does hormonal control determine the action of the CCC
-adrenaline and noradrenaline are released from the adrenal glands increasing the force of ventricular contraction (therefore SV) and increasing the spread of electrical activity through the heart (therefore HR)
what system is actioned if HR needs increasing
sympathetic nervous system
-releasing adrenaline, noradrenaline and sending stimulation to the SA node via the accelerator nerve
what system is actioned if HR needs decreasing
parasympathetic nervous system
-inhibit these effects via the vagus nerve
what is the function of blood
-transport nutrients such as oxygen and glucose
-protect and fight disease
-maintain the internal stability of the body and regulate temperature
what are the structural and functional features of arteries and arterioles
-arteries have a large layer of smooth muscle and elastic tissue to cushion and smooth the pulsating blood flow
-arterioles also have a large layer of smooth muscle allowing both vessels to vasodilate an vasoconstrict to regulate blood flow and control blood pressure
-arterioles also have a ring of smooth muscle surrounding the entry of a capillary bed called pre-capillary sphincters. these dilate and constrict o control the blood flow through the capillary bed
what is vasodilation
widening of arteries, arterioles and pre-capillary sphincters, to deal with high pressures of blood
what is vasoconstriction
narrowing of arteries, arterioles and pre-capillary sphincters
what is the purpose of a capillary
to bring blood slowly into close contact with the muscle and organ cells for gaseous exchange
what is the structural feature of a capillary that allows it to do its job
one cell thick, to allow gas, nutrient and waste exchange
what is venous return
the return of blood to the heart through the venules and veins back to the right atrium
what are the mechanisms of venous return
- pocket valves- prevent the backflow of blood
- smooth muscle- smooth muscle in the vein wall vasoconstricts to aid the movement of blood
- gravity- blood from the upper body, above the heart, is aided by gravity
- muscle pump- skeletal muscle contract, compressing the veins between them, squeezing blood back to the heart
- respiratory pump- during inspiration and expiration, a pressure difference between the thoracic and abdominal cavity is created, squeezing the blood back to the heart
what is the vascular shunt mechanism
the redistribution of cardiac output around the body from rest to exercise which increases the percentage of blood flow to the skeletal muscles
blood flow into the capillary beds is controlled by __________
pre-capillary sphincters
what can pre-capillary sphincters do at the capillary bed
-constrict, which limits blood flow into the capillary bed
-dilate, maximises blood flow into the capillary bed
what is the vasomotor control centre
responsible for cardiac output distribution (vascular shunt)
where does the VCC receive information from
-chemoreceptors- regarding chemical changes
-baroreceptors- regarding pressure changes in the arterial walls
what happens when the sympathetic stimulation is increased due to the VCC information
vasoconstrict arterioles and pre-capillary sphincters to limit blood flow to an area, such as the muscles at rest
what happens when the sympathetic stimulation is decreased due to the VCC information
vasodilate arterioles and pre-capillary sphincters to increase blood flow to an area. such as the muscles during exercise
what are the two main functions of the respiratory system
- pulmonary ventilation
- gaseous exchange
what is external respiration
the movement of oxygen into the blood stream and carbon dioxide into the lungs
what is internal respiration
the release of oxygen to respiring cells for energy production and collection of waste products
what is the structure of the respiratory system
nasal cavity
pharynx
larynx
trachea
bronchi
bronchioles
alveoli
what is gaseous exchange
the movement of oxygen from the alveoli into the blood stream and carbon dioxide from the blood stream into the alveoli
what is alveoli
clusters of tiny air sacs covered in a dense network of capillaries in which together serve as the external site for gaseous exchange
what is haemoglobin
an iron rich globular protein in red blood cells which can chemically combine with four oxygen molecules to form oxyhaemoglobin
define breathing rate
the number of inspirations or expirations per minute
define tidal volume
the volume of air inspired or expired per breath
define minute ventilation
the volume of air inspired or expired per minute
formula for calculating minute ventilation
VE= TV X F
what is the tidal volume of a untrained performer compared to a trained performer
untrained= 500ml
trained= 500ml
what is the breathing rate of an untrained performer compared to a trained performer
untrained= 15-15 breaths/min
trained= 11-12 breaths/min
what is the minute ventilation of an untrained performer compared to a trained performer
untrained= 6-7.5 L/min
trained= 5.5-6 L/min
what is the breathing rate response to exercise
breathing rate increases in proportion to the intensity of exercise until we reach our maximum of around 50-60 breaths per minute. in sub maximal intensities breathing rate can plateau due to the supply of oxygen meeting the demand from the working muscles
what is the tidal volume response to exercise
tidal volume increases initially in proportion to exercise intensity at sub maximal intensities, up to approximately 3 litres. tidal volume reaches a plateau during sub maximal intensity because increased breathing rate towards maximal intensities does not allow enough time and requires too much muscular effort for maximal inspirations or expirations
what is the minute ventilations response to exercise
what are the mechanics of inspiration at rest
-diaphragm contracts, causing it to flatten
-external intercostal muscles contract, causing the rib cage and sternum to move up and out
-thoracic cavity volume increases
-pressure in the lungs decreases below atmospheric pressure
-causes air to move into the lungs from high to low pressures
