run for your life

Question 1

What does myogenic mean?

Answer 1

The ability to contact without external nervous stimulation.
Brings about depolarisation

Question 2

How does the heart beat?

Answer 2

• electrical impulses from the SAN spreads across the atria walls
• impulses pass to the ventricles via the AVN
• impulses pass down the purkyne fibres to the heart apex
• impulses spread up through the ventricle walls causing contraction from the apex upwards, squeezing blood into the arteries

Question 3

What is the Sinoatrial node?

Answer 3

A small area of specialised muscle fibres located in the wall of the right atrium, beneath the opening to the superior vena cava.

Question 4

What is cardiac output?

Answer 4

Cardiac output = stroke volume x heart rate

Question 5

What is VO2?

Answer 5

The oxygen consumption per minute

Question 6

Define aerobic capacity?

Answer 6

The ability to take in, transport and use oxygen

Question 7

What is the structure of ATP?

Answer 7

ATP is a phosphorylated nucleotide composed of ribose, adenine and 3 phosphate groups.

Question 8

What is decarboxylation?

Answer 8

The removal of a carboxyl group from a chemical compound

Question 9

In which reaction is Acetyl CoA produced?

Answer 9

The link reaction

Question 10

How many times does the the link reaction happen for every glucose molecule?

Answer 10

Twice

Question 11

Name a waste product from the link reaction

Answer 11

CO2

Question 12

How many times does decarboxylation occur in the Krebs cycle?

Answer 12

3;

6C -> 5C -> 4C

Question 13

How many molecules of NAD and FAD are produced during decarboxylation and dehydrogenation in the Krebs cycle?

Answer 13

1 reduced FAD

2 reduced NAD

Question 14

What happens when Acetyl CoA is unavailable during the Krebs cycle?

Answer 14

Citrate cannot be made from oxaloacetate

Question 15

what is meant by Tidal volume?

Answer 15

the volume of air in each breath

Question 16

what is meant by Respiratory minute ventilation?

Answer 16

the volume of gas breathed out in a minute

tidal volume x breathing rate

Question 17

what happens to the lid of a spirometer when the person breathes in?

Answer 17

the lid moves up

Question 18

what is the function of soda lime within a spirometer?

Answer 18

absorb the CO2 in exhaled breaths

Question 19

describe how to investigate the effects of exercise on breathing rate using a spirometer

Answer 19

• person breathes into spirometer for 1 min at rest
• exercise for 2 mins, refill spirometer w/ oxygen
• measure again immediately after exercise

Question 20

what is Homeostasis?

Answer 20

Involves control systems which keep internal environment within narrow limits

Question 21

list the mechanisms that increase body temperature

Answer 21

• shivering
• less sweating
• hairs stand up (less air trapped)
• vasoconstriction
• hormones such as thyroxine and adrenaline are released

Question 22

explain how vasodilation decreases body temperature

Answer 22

• arterioles near the surface dilate, more blood flows through the capillaries in the surface layer of the dermis
• more heat is lost from the skin by radiation and the temperature is lowered

Question 23

list the mechanisms to decrease body temperature:

Answer 23

• sweating (water evaporates off the skin, takes heat from body)
• hairs lie flat
• vasodilation

Question 24

which part of the brain maintains temperature?

Answer 24

hypothalamus

Question 25

Name 3 coenzymes involved in respiration

Answer 25

NAD, FAD, Coenzyme A

Question 26

what do the coenzymes FAD and NAD do?

Answer 26

they transfer hydrogen from one molecule to another

Question 27

why is aerobic respiration an example of a metabolic pathway?

Answer 27

its made up of series of chemical reactions

Question 28

what is the net gain of ATP during glycolysis?

Answer 28

2

Question 29

what are the stages of glycolysis?

Answer 29

phosphorylation and oxidation - glucose is phosphorylated -> triose phosphate - triose phosphate is oxidised to form pyruvate

Question 30

what happens in the link reaction? how many ATP are used/produced?

Answer 30

- pyruvate is decarboxylated - NAD is reduced, changes pyruvate into acetate - acetate -> acetyl coA - no ATP involved

Question 31

what is meant by oxidative phosphorylation?

Answer 31

method of synthesising ATP. H+ and electrons recombine to form hydrogen atoms, combining with oxygen to form water. the oxygen acts as final electron acceptor in the ECT and is reduced

Question 32

what happens when baroreceptors detect high blood pressure?

Answer 32

- impulses sent to cardiovascular control centre, sends impulses along parasympathetic neurone - this secretes acetylcholine, which binds to the SAN and stops it beating as frequently

Question 33

what neurotransmitter is secreted when the baroreceptors detect low blood pressure?

Answer 33

sympathetic neurones secrete noradrenaline

Question 34

why is it that distance runners are slower than short distance runners?

Answer 34

longer distance running requires more aerobic respiration | oxygen debt from anaerobic resp cannot be maintained over a duration this long

Question 35

name 3 differences between fast twitch and slow twitch muscle fibres

Answer 35

- slow twitch fibres are fatigue resistant - slow twitch fibres have many mitochondria - slow twitch fibres have many myoglobin

Question 36

what is the fate of lactate after a period of anaerobic respiration

Answer 36

- lactate oxidised into pyruvate, reused in link reaction - transported to liver by blood, broken down into glucose - glycolysis

Question 37

explain the change in oxygen consumption during the ten minutes of rest following exercise

Answer 37

- during exercise, anaerobic resp due to lack of O2 - gycolysis needed to produce ATP, lactate - lots of O2 needed to convert lactate into pyruvate - pyruvate enters krebs cycle and o2 is required for ECT

Question 38

how do you calculate stroke volume?

Answer 38

cardiac output/heart rate

Question 39

how does the appearance of a myofibril change when a muscle contracts

Answer 39

sarcomere shortens, actin and myosin remains same length