Circulatory System Quiz: Arteries to Capillaries

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Questions and Answers

What is the primary risk factor for developing high blood pressure?

Genetics (correct)

Regular physical activity

Being male

Eating salty foods

Which measurement indicates the pressure in the arteries when the heart is contracting?

Diastolic pressure

Pulse pressure

Mean arterial pressure

Systolic pressure (correct)

What can be considered a symptom of low blood pressure?

Increased appetite

High body temperature

Blurred vision (correct)

Rapid heart rate

How can one help prevent high blood pressure?

Practice stress management techniques Signup and view all the answers

What is a potential consequence of chronic high blood pressure?

Kidney damage Signup and view all the answers

Which statement about the systolic pressure is correct?

Normal systolic pressure is about 120 mm Hg. Signup and view all the answers

What health issue can result from untreated high blood pressure?

Heart attack Signup and view all the answers

Which lifestyle factor is NOT associated with an increase in blood pressure?

Regular exercise Signup and view all the answers

What is the primary function of arteries?

Carry blood away from the heart Signup and view all the answers

What layer of tissue in an artery is primarily responsible for its elasticity?

Elastin fibres in the artery walls Signup and view all the answers

What physiological mechanism allows blood vessels to control their diameter?

Vasodilation and vasoconstriction Signup and view all the answers

How thick are the walls of capillaries compared to arteries?

Capillaries have walls that are 1 cell thick Signup and view all the answers

What role do precapillary sphincter muscles play in the circulatory system?

Regulate blood flow to capillary networks Signup and view all the answers

What causes varicose veins?

Damaged valves leading to blood pooling Signup and view all the answers

Which of the following statements about veins is false?

Veins have thicker walls than arteries Signup and view all the answers

In pulmonary circulation, how does blood flow differ from systemic circulation?

Pulmonary veins return oxygenated blood from the lungs to the heart Signup and view all the answers

Study Notes

Arteries

Carry blood away from the heart.
The aorta is the main artery leaving the heart.
Branches into smaller arteries.
Walls have three layers: connective tissue (outer), smooth muscle (middle), and endothelium (inner, single layer of epithelial cells).
Elastin fibers give arteries elasticity, allowing them to expand and contract with each heartbeat, maintaining continuous blood flow.

Arterioles

Smallest arteries.
Diameter controlled by the nervous system (smooth muscle in the walls).
Vasodilation: relaxation of smooth muscle, increasing vessel diameter.
Vasoconstriction: contraction of smooth muscle, narrowing vessel diameter.
Control blood flow to regulate body temperature.

Capillaries

Arterioles branch into capillaries, which form a network throughout the body's tissues.
Deliver oxygen and nutrients to cells.
No cell is far from a capillary.
Walls are only one cell thick.

Blood Flow in Capillaries

Capillary walls lack smooth muscle, so diameter cannot be directly controlled by the nervous system.
Precapillary sphincter muscles control blood flow through capillaries by contracting and relaxing.
Blood flow slows as it enters capillary networks.
Capillaries have a large total cross-sectional area.

Venules and Veins

Capillaries merge into venules, then into veins.
Veins carry deoxygenated blood and waste products back to the heart (systemic circulation).
Vein walls are thinner and less elastic than artery walls.
Veins have one-way valves to prevent backflow.
Muscular contractions assist in blood return.

Artery vs. Vein Comparison

Feature	Artery	Vein
Blood flow	Away from Heart	Towards Heart
Blood pressure	High	Low
Wall thickness	Thick	Thin
Inner diameter	Small	Large
Elasticity	Very elastic	Lacks elasticity
Valves	No	Yes
Oxygen content	Oxygenated (except pulmonary artery)	Deoxygenated (except pulmonary vein)

Pulmonary Circulation

In pulmonary circulation, the pulmonary artery carries deoxygenated blood from the heart to the lungs, and the pulmonary veins carry oxygenated blood from the lungs to the heart.

Varicose Veins

Less elastic vein walls with damaged valves can cause blood pooling and bulging.
More common due to factors like prolonged standing or sitting, aging, and genetics.

Spider Vein Removal

Small, damaged veins, with possible causes including valve failure, increased pressure, and sun damage.

Blood Pressure

Blood pressure measures force against artery walls.
Each heartbeat (cardiac cycle) comprises contraction (systole) and relaxation (diastole).
Systolic pressure (top number): heart contraction, normal ~120 mmHg.
Diastolic pressure (bottom number): heart relaxation, normal ~80 mmHg.

Low Blood Pressure (Hypotension)

Usually not a concern unless symptoms are present.
Possible symptoms: dizziness, fainting, dehydration, fatigue.

Healthy Blood Pressure

Maintaining healthy blood pressure reduces risks of heart attack, stroke, and other vascular diseases.

High Blood Pressure (Hypertension)

High blood pressure damages artery walls.
Can lead to heart attack, stroke, kidney damage, vision loss and other health problems.

Preventing High Blood Pressure

Promote healthy diet, exercise, weight management, stress reduction, and avoidance of smoking and excessive alcohol.

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Description

Test your knowledge of the circulatory system, focusing on the structure and function of arteries, arterioles, and capillaries. Understand the flow of blood and the importance of each component in maintaining bodily functions. Challenge yourself to connect blood flow dynamics with temperature regulation and nutrient delivery.