Human Energy Systems and Muscle Fibres

chemical substances obtained from food

supplies energy to the body

regulates cellular activities

builds and repairs tissue

body requires nutrients to perform life functions

needed to obtain energy for survival

three key energy nutrients are carbohydrates proteins and fats, with carbs being the most important

Anaerocic Alactic (ATP-PC)

- Can occur in two seperate metabolic pathaways (1 involving the breakdown of glucose and the other a partial breakdown)

- Without oxygen (not required).

Anaerobic lactic (glycolysis)

- Without oxygen (not required).

- Can occur in two seperate metabolic pathaways (1 involving the breakdown of glucose and the other a partial breakdown)

Aerobic System (Cellular Respiration)

-With oxygen (required).

-A seperate but to some extent overlapping energy system

-Involves many enzynes and several complex sub-pathways (leads to the complete breakdown of glucose)

slow twitch:
red/dark in color
generate and relax tension slowly
maintains low tension level for long periods of time
ex. long distance running

type 1

generates energy slowly

more fatigue resistance

depends on aerobic processes

fast twitch:
pale in color
can tense and relax quickly
generates large amounts of tension with low endurance levels

type 2a

interediate type muscle fibres

allows high speed energy release and glycolytic capacity

type 2b

stores lots of oxygen (without requiring oxygen)

high level of enzymes necessary for quick contraction

a protein oxygen storage unit that delivers oxygen to the muscles

slow twitch (red) muscle fibres are high in myoglobin and ideal for endurance

fast twitch (pale) muscle fibres are low in myoglobin and more adapted to short bursts of energy

Creatine Phosphate

Used as an energy source for the Anaerobic Alactic system

provides quick short lasting energy.

Glucose

used as an energy source for Anaerobic Lactic system

provides energy quickly

broken down into pyruvate, which is then converted to lactate

Glycogen, fats and proteins

used as an energy source for the Aerobic Lactic system

provides energy during exercise for a prolonged period of time

they are broken down to produce ATP during exerzise

Draws on processes deep within the muscle fibre

Allows for quick, intense muscle contractions

"alactic" does not produce lactic acid as a byproduct

Relies on the action of phosphocreatine (compound normally stored in muscle)

First of 2 anaerobic systems

Yields enough ATP for 10-15 seconds of strenuous activity

examples are weightlifting, 100m sprint, and shot put

partial breakdown of glucose

lactic acid is a byproduct

doesnt involve oxygen (anaerobic)

allows longer bursts of energy

second anaerobic pathway

high level of performance for 100 seconds

lactic acid is produced in the abscence of oxygen, creating a burning feeling in the muscle

yeilds to ATP/ glucose molecule

examples are speed skating, medium distance track events, and a shift in hockey

refers to the process in which body's cell use oxygen to generate energy

through various metabolic pathways in the mitochondria

36 molecules ATP produced/ molecule glucose

over two minutes of activity

examples would be a marathon or a soccer match

1 molecule of ATP is produced in ATP-PC
2 molecules of ATP are produced in glycolysis
36 molecules of ATP are produced in cellular respiration

- allows for the muscles in the body to contract, producing movement

-energy currency of the human body

-adenosine triphosphate