Cardiovascular System

Question 1

How is the skin affected by ageing?

Answer 1

The dermal layer thins as we age. Less collagen is produced and elastin fibres wear out. Skin may become dry due to decreased function of the sebaceous and sweat glands. Fat cells become smaller which can cause skin to sag.

Question 2

How does Botox work?

Answer 2

BoNTA binds to the surface of the nerve cell and is internalised into small vesicles within the nerve. This prevents acetylcholine release by blocking fusion of vesicles with the plasma membrane through cleavage of proteins critical for exocytosis such as SNAP25.

Question 3

Minoxidil may be used to treat pattern baldness and hypertension. How does it work?

Answer 3

Opens K_ATP channels to hyperpolarise the membrane of vascular smooth muscles, making them less sensitive to constriction.

Question 4

What are some normal heart muscle changes associated with ageing?

Answer 4

As we age, the left ventricular wall thickens. There is more collagen and less elastin produced. The heart becomes less efficient and oxygen supply to the body is reduced. These changes may cause fatigue and lower exercise tolerance.

Question 5

What happens to heart valves as we age?

Answer 5

As we age, heart valves become thicker and less flexible. The aortic and mitral valve become calcified. Changes can lead to heart murmurs.

Question 6

What changes occur in the conduction system of the heart as we age?

Answer 6

As we age, the number of pacemaker cells decreases. The conductive system can be infiltrated by fibrous tissue which can lead to arrhythmias.

Question 7

What may an irritated myocardium lead to?

Answer 7

Irritability of the myocardium may result in extra systoles along with sinus arrhythmias and sinus bradycardia.

Question 8

What does heart contraction rely on?

Answer 8

Heart contraction relies on the conducted impulse depolarising the membrane of the cardiac muscle cells. Calcium entering the cell causes contraction.

Question 9

Decreases in what may lead to heart failure in the elderly?

Answer 9

Decreased rate and force of contraction can lead to heart failure.

Question 10

What effects might a decrease in cardiac output cause?

Answer 10

A fall in cardiac output can lead to fatigue, cyanosis, peripheral oedema, jugular vein distention and pulmonary oedema.

Question 11

What causes oedema in heart failure patients?

Answer 11

An imbalance in hydrostatic pressure and osmotic pressure leads to a net outward filtration causing oedema in heart failure patients.
- Hydrostatic pressure forces fluid out at the arterial end of the capillaries
- Osmotic pressure draws fluid in at the venous end of the capillaries

Question 12

How do nitrates treat heart failure?

Answer 12

Nitrates release a vasodilator called nitric oxide which dilates veins, lowering blood return to the heart and reducing workload.

Question 13

How do positive inotropic agents treat heart failure?

Answer 13

Positive inotropic agents block pumps in cardiac muscle, inreasing calcium in the cells to make the heart contract more strongly.

Question 14

How do ACE inhibitors treat health failure?

Answer 14

ACE inhibitors cause the body to produce less AngII through inhibition of an enzyme. This causes blood pressure to be reduced and decreases water retention in the kidneys.

Question 15

How may blood pressure change as we age?

Answer 15

Systolic blood pressure may rise disproportionately to diastolic blood pressure as part of normal ageing.

Question 16

Blood pressure gradually increases with age. What causes this?

Answer 16

Age-related increases in blood pressure are related to structural changes in the arteries, especially stiffness in the large arteries.

Question 17

How is pulse pressure defined?

Answer 17

Pulse pressure = systolic - diastolic

Question 18

Primary hypertension accounts for over 90% of cases and is multifactorial. What are some of these factors?

Answer 18

Factors affecting hypertension include smoking, obesity, diet (salt), lack of exercise and genetics.

Question 19

How might blood vessels change due to ageing?

Answer 19

Larger arteries become stiffer due to reduced elastin levels. Stiffer vessels can lead to systolic hypertension. Vessels may become calcified, leading to difficulties in dilation.

Question 20

Coronary artery blood flow decreases between ages 20 and 60. What effects does this have?

Answer 20

Decreased coronary artery blood flow leads to decreased oxygen delivery to the heart muscle thus decreasing the ability to increase activity.

Question 21

How may ageing affect the aorta?

Answer 21

As we age, the aorta may become dilated, elongated and rigid. It may develop calcifications and become tortuous. Artery walls can weaken in a specific area causing aneurysm.

Question 22

How may high blood pressure be treated?

Answer 22

High blood pressure can be treated by:
- Lifestyle changes
- Drugs affecting the heart such as beta blockers
- Centrally acting drugs
- Hormone antagonists (ACE inhibitors)
- Drugs affecting circulating fluid volumes e.g. diuretics
- Drugs affecting blood vessels - nitrates, calcium channel blockers, potassium channel openers

Question 23

How does Propranolol affect the heart?

Answer 23

Propranolol blocks beta adrenoreceptors on the heart, reducing force of contraction and heart rate.

Question 24

What are the first line hypertension treatments for those younger than 55 years old who are not black?

Answer 24

ACE inhibitors are first line hypertension treatment for those younger than 55 years old who are not black.

Question 25

What are the first line hypertension treatments for those older than 55 years old or who are black?

Answer 25

Calcium channel blockers or thiazide-type diuretics are first line hypertension treatments for patients who are black or are over 55 years old.

Question 26

What is atherosclerosis?

Answer 26

Atherosclerosis is an inflammatory disease which affects large and medium sized arteries.
- It begins with the appearance of fatty streaks in aorta and develops into raised lesions as lipid uptake increases. Inflammatory cells present in the artery wall. A fibrous cap forms to protect lesion.

Question 27

What types of drugs may be used to treat atherosclerosis?

Answer 27

Atherosclerosis may be treated using drugs which lower lipid levels, which prevent platelets from sticking to the fibrous cap, which lower blood pressure or which prevent symptoms of coronary ischaemia.

Question 28

Metformin is a drug which is usually used to treat Type 2 diabetes. Which other conditions may it be used to treat?

Answer 28

Metformin may be used to treat Alzheimer’s Disease, ischaemic stroke and caner.

Question 29

Which protein kinase complex is activated by Metformin?

Answer 29

Metformin activates AMPK.

Question 30

What effects does the activation of AMPK by Metformin have on the body?

Answer 30

Activation of AMPK by Metformin leads to reduced hepatic glucose production, reduced intestinal absorption of glucose and increased local utilisation of glucose.

Question 31

True or false: Metformin causes weight gain.

Answer 31

False - Metformin does not cause weight gain, making it useful in the treatment of Type 2 diabetes.