Heart & Circulation

Question 1

The Sino-Atrial node (SA node)

Answer 1

Produces the electrical impulse that travels across both atria causing them to contract

Question 2

Atrio-ventricular node

Answer 2

Point at which signals travel from the atrium to the ventricles. They then travel down the interventricular septum and around and up the walls of the ventricles

Question 3

The heart wall

Answer 3

Endocardium: the inside lining
Myocardium: the muscle wall
Pericardium: the outer fibrous sac (visceral layer on heart, pericardial cavity with fluid, parietal layer)

Question 4

Controlling blood pressure short term

Answer 4

Autonomic system
Barorreceptors in the aorta and carotid artery sense change in pressure
Signal brain
Brain alters vessel resistance, heart rate, beat strength

Question 5

Controlling blood pressure long term

Answer 5

Endocrine
Kidneys detect drop in pressure
Release renin
Renin converts angiotensinogen into angiotensin 1
Angiotensin 1 reaches the lungs and ACE converts into angiotensin 2
Angiotensin two causes the vessels to constrict, the secretion of aldosterone and ADH

Question 6

Mean arterial pressure

Answer 6

One third of the way between diastole and systole
Eg. 90/45
90-45=45
1/3 of 45 = 15
45+15=60
Below 60 mean arterial pressure is an emergency

Question 7

Trachea> bronchus> bronchioles

Answer 7

Cartilage rings become more like plates as you move down then disappear. They are not on the bronchioles as these can constrict and dilate

Question 8

Inspiration muscles

Answer 8

Diaphragm and external intercostal muscles

Question 9

Expiration muscles

Answer 9

Abdominal muscles and internal intercostal muscles

Question 10

The pleura and intra pleura space

Answer 10

Causes the lungs to expand

The elastic recoil causes the lungs and attached chest wall to collapse

Question 11

Normal gas values in the blood

Arteries. Veins

Answer 11

Partial pressure O2: 90mmHg 30mmHg
Partial pressure CO2: 40mmHg 45mmHg
Oxygen saturation: 100% 60%

Question 12

Chemoreceptors

Answer 12

In the brain and carotid artery detect changes and alter breathing accordingly

Question 13

Measuring respiration clinically

Answer 13

Peak flow metre
Measures speed air comes out of lung» how open they are
Forced vital capacity
Measures how much you can breath out
Forced expiration volume in 1 second
How much you can breath out in one second. Should be 70-80% capacity.