A level Pe - Applied anatomy and physiology

What two factors change heart rate?

Neural control mechanism and hormonal control mechanism

What are chemoreceptors?

Detect an increase in blood CO2 levels

What are baroreceptors?

Detect increase in blood pressure

What are proprioceptors?

Detect increase in muscle movement

How does the neural control mechanism work?

Chemoreceptors, baroreceptors and proprioceptors detect change. This sends a signal to the cardiac control centre located in the medulla oblongata of the brain. This send an impulse via either the sympathetic or parasympathetic system to the SAN to increase/decrease heart rate

What is the hormonal control mechanism?

Adrenaline is released by the sympathetic nerves and cardiac nerves, which stimulate the SAN, increasing the speed and force of contraction, increasing cardiac output

What is stroke volume?

the volume of blood pumped from the left ventricle per beat - average = 70ml

What is ejection fraction?

The % of blood pumped out by the left ventricle per beat

What is venous return

The return of blood to the right side of the the heart via the vena cava

What factors affect stroke volume?

Venous return

The elasticity of cardiac fibres

The contractility of cardiac tissue

What is Starling's law of the heart?

Increased venous return = greater diastolic filling = cardiac muscle stretched = greater force of contraction = increased ejection fraction

What is an anticipatory rise?

Rise in HR due to adrenaline which causes SAN to increase heart rate

How is cardiac output calculated?

stroke volume (SV) x heart rate (HR)

What is heart disease?

When coronary arteries which supply heart with oxygenated blood become blocked or narrowed, caused by high blood pressure, high cholesterol, lack of exercise and smoking

What is high blood pressure?

Large force exerted against the blood vessel walls, putting strain on arteries and the heart. Can be helped by regular aerobic exercise

What are the two types of cholesterol?

HDL (good) and LDL (bad)

Regular activity lowers LDL and can increase HDL

What are the two types of stroke?

Ischaemic - blood clots stops blood supply

Haemorrhagic - blood vessel bursts

Both can have reduced chance by regular exercise lowering blood pressure

What is cardiovascular drift?

Increase in heart rate in prolonged exercise due to a decreasing stroke volume due to decreased volume of blood plasma due to sweating

Different blood vessels

Arteries -Carries blood away from the heart at high pressure. Strong and elastic thick muscle to make them strong.

Capillaries - These are involved in the exchange in the exchange of materials at the tissues. Permeable wall to allow exchange of materials.

Veins- These carry blood to the heart. Not that thick, but have valves to keep blood flowing in the right direction.

blood pressure

the pressure that is exerted by the blood against the walls of blood vessels

Blood flow times by resistance

Measure in mmHg

Venous return mechanisms

Skeletal muscle pump - muscles contracting putting pressure on veins

Respiratory pump - contraction of muscles when breathing put pressure on veins

Pocket valves - calves that prevent backflip

Gravity - from upper body

impact of blood pressure on venous return

As systolic BP increases venous return increases due to greater pressure in vessels.

How is oxygen transported in the blood?

3% dissolved in plasma

97% forms oxyhaemoglobin

Oxyhaemoglobin dissociation

The release of the oxygen from Oxyhaemoglobin to the tissues, where myoglobin transports it into the muscles to be stored

oxyhemoglobin dissociation curve

Relationship between partial pressure of oxygen and percentage saturation of haemoglobin.

Bohr shift

The shift to the right when muscles require more oxygen during exercise, meaning dissociation of O2 occurs more readily. This is caused by an increase in blood temperature, an increase in PpCO2 in the blood and lower blood PH levels

Redistribution of blood during exercise

Known as vascular shunt mechanism and ensures blood flow:

Increases to the heart - to beat faster

Increases to the muscles - more O2 needed

Increases to the skin - to cool down

Stays the same in the brain

Why is it important the gut is empty during exercise?

More blood would need to be directed to the gut instead of the working muscles, reducing performance

How does the vasomotor control center regulate blood flow?

Chemical changes detected by chemoreceptors during exercise. Stimulates the vasomotor control centre in the medulla oblongata. Causes vasodilation and vasoconstriction. Vasodilation will occur in arterioles leading to working muscles to increase blood supply and hence oxygen supply

A-V02 difference

The difference between the o2 content of the arterial blood arriving at the muscles and the venous blood leaving the muscles. Increases during exercise as more O2 dissociates

tidal volume

Volume of air inspired or expired per breath

minute ventilation

total volume of air inhaled and exhaled each minute

No of breaths times by tidal volume

inspiratory reserve volume

Amount of air that can be forcefully inhaled after a normal tidal volume inhalation

expiratory reserve volume

Amount of air that can be forcefully exhaled after a normal tidal volume exhalation

residual volume

Amount of air remaining in the lungs after a forced exhalation

How do lung volumes change during exercise

TV - INCREASES

MV - INCREASES

IRV - DECREASES

ERV - SLIGHT DECREASE

RV - SAME

Gaseous exchange is concerned with...

Getting O2 in the air into the lungs for diffusion into the blood

The removal of CO2 from the blood

partial pressure

the pressure exerted by a gas in a mixture of gases

How are alveoli adapted for gas exchange?

• large surface area

• good blood supply

• thin - short diffusion pathway

• moist - dissolve gases

What three factors are involved in pulmonary ventilation regulation?

Neural control

Chemical control

Hormonal control

Neural/chemical control for increased inspiration during exercise

Receptors - medulla oblongata - phrenic nerve - inspiratory muscles diaphragm and external intercostal muscles

Neural/chemical control for expiration during exercise

Receptors - medulla oblongata - intercostal nerve - abdominals and internal intercostal muscles

Hormonal regulation of pulmonary ventilation

Adrenaline is released increasing breathing rate

How does smoking affect the respiratory system?

Carbon monoxide combines with haemoglobin reducing oxygen carrying capacity of the blood

Irritation of the trachea and bronchi

Swelling and narrowing of airways

Damage to cells lining the lungs leading to a build up of mucus

Reduction in the efficiency of gaseous exchange

What are type 1 muscle fibers?

Slow oxidative fibres that have a slow contraction speed and are adapted for lower intensity exercise

What are type 2a muscle fibres?

Fast oxidative glycolytic fibres that have a fast contraction speed but are more resistant to fatigue so are used in events such as 1500m

What are type 2b muscle fibres?

Fast glycolytic fibres with a fast contraction speed used for explosive events such as the 100m

Functional characteristics of type 1 muscle fibres

Slow contraction speed

Slow motor neurone conduction capacity

Low force produced

Low fatigability

Very high aerobic capacity

Low anaerobic capacity

Structural characteristics of type 1 muscle fibres

Small motor neurone size

High mitochondrial density

High myoglobin content

High capillary density

Functional characteristics of type 2a muscle fibres

Fast contraction speed

Fast motor neurone conduction capacity

High force produced

Medium fatigability

Medium aerobic capacity

High anaerobic capacity

Structural characteristics of type 2a muscle fibres

Large motor neurone size

Medium mitochondrial density

Medium myoglobin content

Medium capillary density

Functional characteristics of type 2b muscle fibres

Fast contraction speed

Fast motor neurone conduction capacity

High force produced

High fatigability

Low aerobic capacity

Very high anaerobic capacity

Structural characteristics of type 2b muscle fibres

Large motor neurone size

Low mitochondrial density

Low myoglobin content

Low capillary density

What is a motor unit?

a motor neuron and all the muscle fibers it supplies

What is the all or none law?

When a motor neurone stimulates the muscle fibres all of them have to contract, or none of them, it cannot partially contract. A threshold needs to be reached to achieve the contraction

What is wave summation?

Where there is a repeated activation of a motor neurone with no time to relax, so a smooth sustained contraction occurs. This is due to calcium being released which is needed for a muscle to contract, so it builds up in the muscle. This is known as a tetanus contraction.

What is spatial summation?

Impulses are received at the same time at different places on the neurone. Involves the recruitment of bigger and additional motor units for a greater force of contraction. Strength of contraction can be changed by altering the number and size of the motor units.

What are muscle spindles?

Proprioceptors that detect how far a muscle is being stretched and send the signal to the CNS. These cause a stretch reflex to prevent a muscle being overstretched

What are golgi tendon organs?

They detect levels of tension within a muscle. When contracting a muscle GTO send signals to the brain which cause the antagonist to relax, known as autogenic inhibition

What is the CRAC technique

A Proprioceptive neuromuscular facilitation (PNF) technique that stands for Contract - Relax - Antagonist - Contract

How does PNF stretching work?

Passive stretch until tension is felt / stretch reflex

The individual isometrically contract causing tension in the muscles

This is detected by the Golgi tendon organs and send inhibitory signals or the antagonist to relax and lengthen, delaying the stretch reflex

The leg can be stretched further

Joint type and articulating bones at the ankle

Hinge joint, talus tibia and fibula

Joint type and articulating bones at the knee

Hinge, femur and tibia

Joint type and articulating bones at the shoulder

Ball and socket, scapula and humerus

Joint type and articulating bones at the hip

Ball and socket, pelvis and femur

Joint type and articulating bones at the elbow

Hinge, radius ulna and humerus

What joint actions occur in the Sagittal plane and transverse axis

Hip flexion/extension

Elbow flexion/extension

Knee flexion/extension

Ankle plantar/Dorsi-flexion

Shoulder flexion/extension

What joint actions occur in the frontal plane and sagittal axis

Hip and shoulder adduction and abduction

What joint actions occur in the transverse plane and longitudinal axis

Shoulder and hip horizontal adduction and abduction

Antagonistic pair at the elbow

bicep and tricep

Antagonist pair at the ankle

Tibialis anterior and gastrocnemius

Antagonistic pair at the knee

quadriceps and hamstrings

Antagonistic pair for hip flexion/extension

Iliopsoas/hip flexors and gluteals

Antagonistic pair for hip adduction/abduction

Abductors (adductor brevis, longus and Magnus) and tensor fascia Latae/gluteus medius/gluteus minimus

Antagonistic pair for hip horizontal abduction/adduction

Adductors and tensor fascia latae/gluteus medius and minimus

Antagonistic pair for shoulder flexion/extension

Anterior deltoid and latissimus dorsi

Antagonistic pair for shoulder abduction

Middle deltoid working, posterior deltoid relaxing

Antagonistic pair for shoulder horizontal abduction

Latissimus dorsi working, pectorals relaxing

What is an isotonic contraction?

A muscle contracts to create movements

What is a concentric contraction?

When a muscle shortens under tension

What is an eccentric contraction?

When a muscle lengthens under tension

What is an isometric contraction?

A muscle contracts without lengthening or shortening so no movement occurs I.e crucifix position

Three stages of aerobic respiration

glycolysis, krebs cycle, electron transport chain

What happens in glycolysis in aerobic respiration

Takes place in the sarcoplasm of the muscle

The breakdown of glucose into pyruvic acid by the enzyme phosphofructokinase

A net of two molecules of ATP are formed

Then splits into two acetyl groups before being carried into the mitochondria matrix by coenzyme A

What happens in the Krebs cycle in aerobic respiration

Acetyl co-enzyme A diffuses in to the matrix of the mitochondria. Acetyl co-enzyme A combines with oxaloacetic acid, forming citric acid. oxidative carboxylation occurs and hydrogen and carbon are given off. the carbon forms CO2 and is taken to the lungs, and the Hydrogen is used in the electron transport chain. Net gain of two molecules of ATP from this section

What happens with fats in the Krebs cycle

fatty acids undergo a process called beta oxidation, where they are converted into acetyl coenzyme A and used normally in the Krebs cycle

what happens in the electron transport chain in aerobic respiration

occurs in the cristae of the mitochondria. hydrogen is split into hydrogen ions and electrons which are charged. These H ions re oxidised to form water, while the electrons provide energy for re-synthesis of ATP. This produces 34 ATP

How does the ATP PC system work

PC = P + C + ENERGY

ENERGY + ADP + P = ATP

ATP = ADP + Pi + Energy

Anaerobic - only max of 10 seconds

How does the lactate anaerobic system work

Glucose broken down into pyruvic acid by phosphofructokinase realeasing 2 ATP

Anaerobic process so pyruvic acid is broken down into lactic acid by lactate dehydrogenase

Happens in the sarcoplasm if the muscle

oxygen consumption

The amount of oxygen we use to produce ATP, usually referred to as V02

Submaximal oxygen deficit

When there is not enough oxygen available at the start of exercise to provide all energy aerobically

What does EPOC mean?

excess post-exercise oxygen consumption

What is epoc

The amount of oxygen consumed during recovery above what would have been consumed at rest in the same time period

What happens in the fast replenishment stage of EPOC

Extra oxygen taken in is used to replenish ATP and phosphocreatine stores, as well as re-saturate myoglobin with O2

What happens in the slow replenishment stage of EPOC

Removal of lactic acid

Maintenance of breathing and heart rates

Glycogen replenishment

Increase in body temperature

How is lactic acid removed during EPOC

Oxidised into CO2 and water and used as an energy source

Transported in blood to the liver where it is converted to blood glucose and glycogen, know as the cori cycle

Converted into protein

Removed in sweat and urine

How does maintaining heart and breathing rates assist recovery

Extra O2 is taken in which can be used to replenish stores of ATP and Phosphocreatine as well as re-saturate myoglobin

How can glycogen be replenished after exercise

Lactic acid converted by cori cycle

High carbohydrate meal

How does elevated body temperature aid recovery

Respiratory rates will also remain high, helping the performer take in extra oxygen during recovery

What is the lactate threshold?

The point during exercise at which lactic acid quickly accumulated in the blood