Applied Anatomy and Physiology

Question 1

Cardiovascular system

Answer 1

Heart – 4 chambers (2 atria/2 ventricles)
right atrium collects de-oxy blood, from the body
right ventricle pumps this into the lungs
left atrium collects oxygenated blood from the lungs
left ventricle pumps this out to the body

Question 2

Cardiac cycle

Answer 2

0.8 seconds (approx 72bpm)
Systole (0.3 seconds)
- rapid contraction
Diastole (0.5 seconds)
- resting phase

Question 3

Coronary blood supply

Answer 3

left and right coronary arteries
arise from coronary sinus behind aortic valve
receive 5% of cardiac output
only fill during diastole
above 180bpm filling is erratic

Question 4

Regulation of the heart

Answer 4

Local cardiac reflexes
- SAN, AVN
- Starlings law (greater the heart muscle is stretched, the greater the force of contraction. It helps to coordinate blood entering and leaving the heart as well as helping coordinate the L and R side of heart)

Neural
- parasympathetic
- sympathetic

Hormonal
- adrenaline
- cortisol

Question 5

Clinical implications of anxiety

Answer 5

inc HR
sign inc can lead to cardiac hypoxia
in pts with atherosclerosis of of coronary arteries coronary blood flow is already compromised
hypoxia and ischaemia can occur at HR of <180 bpm

Question 6

Blood pressure

Answer 6

Maintains blood flow
High BP inc risk of MI, stroke, kidney disease
Sedative drugs can affect BP
BP = Peripheral resistance x Cardiac Output
Systolic - 120mmHg
Diastolic - 80 mmHg

Question 7

Peripheral resistance

Answer 7

Mainly in arterioles
4th power law
arterioles under continuous sympathetic tone
vasomotor centre

Question 8

Cardiac output

Answer 8

CO = Stroke volume x heart rate
Stroke vol - 70ml
HR - 72bpm
CO = 5 l/m

Question 9

Factors affecting BP

Answer 9

Baroreceptor mechanism
Chemoreceptors
Renin-angiotensin system
Sensory nerves
Higher centres
Drugs – antihypertensives