Blood & Respiratory Systems

Question 1

What is the respiratory rate at rest?

Answer 1

12-18 breaths per minute

Question 2

Describe increase in alveolar ventilation

Answer 2

increases tidal volume and respiratory rate

Question 3

What are the components of blood?

Answer 3

Platelets
White blood cells
Red blood cells
Plasma

Question 4

Describe red blood cells

Answer 4

Erythrocytes - large volume to surface area ratio
therefore faster exchange between interior and surrounding plasma
-form stacks
-bends and flex’s so RBCs pass through capillaries as narrow as 4um
-specialised to carry O2 and CO2

Question 5

What is Dalton’s law?

Answer 5

pressure exerted by a mixture of gasses = pressure exerted by the sum of the pressures that would be exerted by the individual gasses occupying the same volume alone

Question 6

What is Henry’s law?

Answer 6

concentration of solute gas in solution is directly proportional to the partial pressure of the gas above the solution

Question 7

Describe haemoglobin

Answer 7

Protein found in erythrocytes capable of binding O2 in an easily reversible manner
- 4 subunits containing Fe2+

Question 8

What does O2 binding to haemoglobin depend on?

Answer 8

Depend on amount of O2 molecules already bound
Binding changes the confirmation, increasing the affinity to oxygen so oxygen is more likely to bind
- Positive cooperatively

Question 9

Describe CO2 transport

Answer 9

CO2 diffuses via interstitial fluid into plasma in systematic capillaries
-CO2 diffuses into erythrocytes where it is converted into HCO3- and H+ catalysed by carbonic acid

Question 10

What is the Haldane effect?

Answer 10

O2 binding to the Hb decreases affinity of Hb for CO2 therefore when PO2 increases, increase in CO2 is loaded from HB therefore effect increases rate of CO2 elimination ion the lungs

Question 11

Describe heart rate increase linearly with work rate

Answer 11

• increase is a result of decrease vagal inhibition

- increase sympathetic stimulation of pacemaker cells in the sino atrial node

Question 12

Describe cardiovascular exercise changes

Answer 12

• changes in autonomic nerve activity triggered by cardiovascular centre
• central command hypothesis
• peripheral reflex hypothesis

Question 13

Describe the central common hypothesis

Answer 13

proposes that cerebral cortex both initiates voluntary muscle contraction and commands the autonomic neurones in the brainstem

Question 14

Describe the peripheral reflex hypothesis

Answer 14

Proprioceptor inputs from joints and muscle and chemoreceptor inputs from muscle contribute to cardiovascular response to exercise

Question 15

What is hypernea?

Answer 15

combined effects of several chemical and neural stimuli initiate and modulate the respiratory adjustments to exercise

Question 16

Describe the Hypernea mechanism

Answer 16

1. peripheral and central chemoreceptors respond to change
2. cardiovascular mechanoreceptors in systematic and pulmonary circulations
3. mechanoreceptors in muscle - respond to change in length and tension of exercising muscle
4. receptors monitoring blood gas levels (O2 +CO2) and metabolic activity in muscle
5. Receptors monitoring blood gas levels (O2 +CO2) in mixed venous blood