The tears will cause swelling in your muscle, this creates pressure on the nerve endings as well as pain.
Hypertrophy will only happen if the body gets the correct nutrition and rest to repair the micro tears.

Repair of the tears will make the muscle a little bit stronger than it was before. A sporting example would be a rugby player using weights to improve his upper body strength. He could do some bicep curls.

Your Heart Rate can rapidly change by chemicals released from your brain.

It tells the heart to prepare for exercise thus increasing Heart Rate.

Your blood pressure should be 120/80. Systolic Bloodpressure is the highest pressure within bloodstream. Occurs when the heart is contracting.

Diastolic blood pressure is the lowest pressure within bloodstream. This occurs when the heart is relaxing.

Your oxygen consumption and heart rate increases in relation to the intensity of the activity, therefore increasing your Blood Pressure

When you start to exercise there is an immediate and a big increase in breathing rate.

This is a result of receptors working in the musculoskeletal system.

Your Muscles demand more oxygen during exercise. your carbon dioxide levels increase as a result of increased energy production.
Breathing rate increases to satisfy these demands

Your capillary surrounding the alveoli expands to help improve blood flow.This results in increased blood flow to your lungs.

When you exercise your tidal volume increases to allow more air to pass through your lungs. This then allows you to get more oxygen into your blood. A sporting example would be a rugby player having a rest during the game, the more air he can get into his lungs the quicker he can recover.

Therefore it can only be used for exercise up to 2-3 minutes

The way the lactic acid system works is by our body breaking down glucose or glycogen to generate ATP through a process called Anaerobic glycolysis. If oxygen isn’t present the body will also produce lactic acid in the process

1 molecule of glucose will produce 2 molecules of ATP

1 molecule of glycogen will produce 3 molecules of ATP

Glycogen is stored in the muscles and liver

Lactic acid gathers and diffuses into the tissue fluid and blood.

If this fluid isn’t removed(by the circulatory system) it will build up and affect muscle contractions. It will cause the muscles to fatigue and cramp.This then makes muscles feel heavy and tired, which affects an athlete's performance. 

The lactic acid energy system would be used in events where you work anaerobically. For example in a game of football when you are sprinting to get to the ball. 

It can only generate ATP in the presence of oxygen.

It is used for long distance events or exercises lasting longer than 5 minutes, for example in a 5,000 meter race.

Begins the same way the lactic acid energy system does- breakdown of glucose and glycogen

If oxygen is present lactic acid will not be produced and instead more ATP is formed through Aerobic glycolysis

Generates ATP much slower than Anaerobic glycolysis and even more slower than ATP-PC system therefore is used for low intensity/long duration exercise.

With oxygen 1 glucose molecule generates 36 molecules of ATP

1 glycogen molecule generates 37 molecules of ATP

Fatty acids are broken down to produce 129ATP