Topic E - Cardiovascular system, cardiovascular diseases and the eye P3-4

Question 1

what are the functions of arteries, capillaries and veins?

Answer 1

• Arteries – carry blood away from the heart to
capillaries (smallest arteries = arterioles)

Capillaries – allow for the exchange of materials
between the blood and tissues.

Veins – deliver blood from the capillaries back to the
heart (smallest veins = venules)

Question 2

how does exchange of nutrients in the capillaries occur?

Answer 2

• Oxygen & nutrient diffuse from blood in capillaries into
the tissue fluid & into body cells
• CO2/metabolic wastes diffuse in the opposite direction

Capillaries walls are a single
endothelial cell thick, allowing for
faster exchange of materials
between blood & tissue fluid

Question 3

what are the 3 layers of the artery and vein?

Answer 3

1. Tunica externa - Connective tissue (outer layer),
   provide elasticity
2. Tunica media - Smooth muscle (middle, thickest
   layer), provide support & produce changes to the
   diameter
3. Tunica interna – Endothelium (inner layer)

Question 4

What are 5 differences between arteries and veins

Answer 4

1. muscular walls:
   artery has more smooth muscle & connective tissue – thicker
   muscular layer to withstand higher blood pressure

veins have thinner muscular layer

2. lumen size: arteries have smaller lumen

veins have larger lumen

3. colour: arteries appear lighter (O2 rich)

veins appear darker (O2 poor)

4 & 5. type of blood carried and presence of valves : arteries carry blood from heart – higher
pressure and need to reach cells fast,
low volume of blood, no valves

veins carry blood to heart – lower pressure,
high volume of blood, has valves

Question 5

what are 3 ways that assist in venous blood being returned to the heart?

Answer 5

• Skeletal muscle contractions (eg. In legs & arms)

• Respiratory movements (eg. contraction of diaphragm during
breathing)

• Gravity (eg. upper body parts, superior to heart

Question 6

what is bp? what is the normal bp?

Answer 6

• Refers to arterial blood pressure in the systemic circuit – in
aorta & its branches

Normal BP: 120/80

Question 7

what are the 4 factors affecting bp?

Answer 7

• Cardiac output= amount of blood pumped by each ventricle of the heart in one minute

Changes in CO will change BP as the blood volume or heart rate
changes

• Blood volume
Eg. Low volume, Low BP

May decrease by severe haemorrhage, vomiting, diarrhoea, or
reduce water intake, and reduce BP due to loss of fluid.
If body retains too much fluid, blood volume & BP increases

• Peripheral resistance (PR) – artery wall flexibility & diameter

It is the friction of blood against walls of blood vessels
When arterioles change diameters, it alters PR & control BP.
Eg. When it constricts, PR & BP increase & when it dilates, PR &
BP decreases.

• Blood Viscosity Eg. Thick/high concentration blood, high BP

It is the resistance of a liquid to flow. It is determined by
concentration of blood cells & plasma proteins. Increase in either
of their concentration increases blood viscosity & BP.

Question 8

What are the 4 effects of aging/hypertension on the

heart?

Answer 8

• heart become less efficient due to decreased
resting stroke volume – so lower CO.

• the vessel walls thicken and become less elastic

• vascular resistance increases with age in individuals
with hypertension.

• CO decreases as heart rate decreases.

Question 9

what is hypertension (HT) and hypotension?

Answer 9

HT: Refers to chronic high blood pressure
greater than 140/90 mmHg

Hypotension – chronic low BP, below 90/60 mmHg

**pre HT: 120-139/80-89 mmHg

Question 10

what effects does HT have on the heart and the blood vessels?

Answer 10

• The heart become less efficient due to decreased
resting stroke volume, which decreases cardiac
output.

• The blood vessels thicken and become less elastic

• Vascular resistance .increases with age in individuals
with hypertension.

Question 11

what are the causes of HT? how does HT cause change in the eye after > 10 years of onset?

Answer 11

• Causes
• Idiopathic (unknown cause)
• Secondary to
• Diabetes
• Kidney disorder

• Fundus (back of eye) changes usually in 50-60s
( > 10 years duration)

Question 12

how does HT affect the brain, retina, heart, blood and kidneys

Answer 12

brain:

• strokes
• hypertensive encephalopathy (confusion, headache and convulsion)

retina of eye:
-hypertensive retinopathy

heart:

• heart attack
• heart failure

blood:
-elevated sugar levels

kidneys:
-chronic renal failure

Question 13

what is atherosclerosis?

Answer 13

• Is the formation of fatty deposits in
the tunica interna of arterial
walls

• this reduce the lumen of the arteries
and increase the probability of thrombosis– reducing
blood flow

may lead to serious circulatory
problems/ischemia & eventually
damage the tissue. 
"eye stroke“ may results, causing
blindness in one eye.

**Arteriosclerosis – is hardening of the
arteries. It results from calcium
deposits in the tunica media &
usually associated with
atherosclerosis

Question 14

what is a stroke and how does it affect the eye? how can it be treated?

Answer 14

• Occurs when blood supply to part of brain is blocked (eg,
as result of embolus or thrombus/blood clot)
• The brain cells/tissue around it will die in few minutes
(due to lack of oxygen & nutrient)

Stokes can cause vision problems including visual
field loss, double or blurry vision

• Treatment include medication to remove the
thrombus/blood clot, or surgery to clear the bleeding, repair vessels, regulate the pressure

Question 15

what is Hyperlipidemia/High cholesterol? What are some complications that come along with hyperlipidemia?

Answer 15

• High level of lipid/fat (cholesterol and triglycerides)
in the blood

• People with hyperlipidemia may have complications such as Hypertension,
Atherosclerosis, Stroke & affects the eyes

Question 16

what is optic neuropathy?what are some symptoms ?

Answer 16

Sudden severe transient loss of vision
Thickening of temporal
artery

Swelling/ thickening of
temporal arteries
-Temporal HA
-Scalp tenderness
-‘mini stroke’