Cardiovascular & respiratory systems

Question 1

What is the order of heart conduction system?

Answer 1

Atrial and ventricular diastole
SAN
Atrial systole
AV
Bundle of his
Purkyne fibres
Ventricular systole

Question 2

Heart rate

Answer 2

MHR 220-age

average 70-72 bpm

Below that is bradycardia

Question 3

Stroke volume

Answer 3

Volume of blood ejected from the heart per beat

Question 4

Cardiac output

Answer 4

Volume of blood ejected from heart per min
Q=HRxSV
resting Q approx 5 l/min

Question 5

Cardiac response to exercise

Answer 5

Increased breathing rate to got more oxygen into the body and more carbon dioxide out.
Increase blood transportation to get oxygen to muscles and carbon dioxide out of muscles
HR, SV and Q increase

Question 6

Untrained performer

Answer 6

A
HR 70-72bpm 100-130bmp 220-age

SV. 70ml. 100-120ml. 100-120ml

Q. 5 l/min. 10-15 l/min. 20-30 l/min

Question 7

Trained athlete

Answer 7

HR. 50bpm. 95-120bpm. 220-age

SV. 100ml. 160-200ml. 160-200ml

Q. 5 l/min. 15-20 l/min. 30-40 l/min

Question 8

Stoke volume response to exercise

Answer 8

SV increases in proportion to exercise intensity until a plateau at 40-60% of working capacity

Question 9

Why does stroke volume increase?

Answer 9

Increased venous return
Greater volume of blood returning to the heart and filling the ventricles

Starlings law
SV is dependent on venous return.
Increased end-diastolic volume and greater stretch on ventricular walls.
Ejects larger volume of blood

Question 10

Cardiac output response to exercise

Answer 10

Increases inline with intensity of exercise and plateaus during maximal exercise

Question 11

Capillaries

Answer 11

1 cell thick and single walled
Epithelial cells

Question 12

Arteries and arterioles

Answer 12

Middle layer of smooth muscle for vasodilation and vasoconstriction.

Ring of smooth muscle called pre-capillary sphincter regulates blood.

Question 13

Veins and venules

Answer 13

Venodilate and venoconstrict
Pocket valves prevent back flow of blood.
Thick outer layer supports blood in pocket valves.

Question 14

Vascular shunt
How do arterioles and pre capillary sphincters know when to contract?

Answer 14

-Controlled by Vasomotor control centre in medulla oblongata
-Smooth muscle always in vasomotor tone
-VCC uses Sympathetic nervous system

Accelerator nerve to SA node
Chemoreceptors - chemical changes co2
Baroreceptors - blood pressure
Proprioceptors - movement

Question 15

Ccc divided

Answer 15

Sympathetic - increase HR
Parasympathetic- decrease HR

Question 16

What nerves does ccc use?

Answer 16

Sympathetic- accelerator

Parasympathetic- vagus

Question 17

what 3 things also effect the SA node?

Answer 17

neural factors
hormonal factors
intrinsic factors

Question 18

how does neural control work?

Answer 18

CCC stimulated by sensory receptors

-proprioceptors: in muscles, tendons and joints - inform CCC that motor activity (movement) has increased.
-chemoreceptors: detect chemical changes in muscles, aorta and carotid arteries - inform CCC lactic acid and CO2 levels increased and O2 and pH level decreased
-baroreceptors: sensitive to stretch within blood vessel walls, in aorta and carotid arteries - inform CCC blood pressure has increased

Question 19

how does ccc respond to neural information?

Answer 19

CCC responds to the neural information by stimulating SA node via accelerator nerve (SNS) to increase HR and SV

after exercise stops, neural factors reversed gradually and ccc increases stimulation via vagus nerve (PNS) for the SA node to decrease HR

Question 20

what is hormonal control?

Answer 20

-SNS stimulates adrenal glands to release adrenaline and noradrenaline into the blood stream

-noradrenaline: neurotransmitter
-adrenaline: hormone

-stimulates SA node to increase HR and strength of ventricular contraction = increase in SV
-during recovery, PNS inhibits release of adrenaline and noradrenaline = HR decreases

Question 21

what is intrinsic control?

Answer 21

-during and after exercise there are a number of intrinsic factors that affect HR control

during exercise
-temperature increases: increases speed of nerve impulse = increases HR
-venous return increases HR: increases EDV (increased stretch on ventricle walls) and therefore SV

after exercise
-temperature decreases = HR decreases
-VR decreases = decreases SV