Anatomy and Physiology 2 - Vessels (Study Questions)

What are the three layers that make up the walls of a vessels, and what is the function of each?

The three layers that make up the walls of a vessel are:

1. Tunica Intima: This is the innermost layer and is smooth to allow blood to flow easily.

2. Tunica Media: This middle layer is made of muscle and helps control the diameter of the vessel, which regulates blood flow and pressure.

3. Tunica Externa: The outermost layer provides support and protection to the vessel.

What are the different types of vessels in the body, and how are they unique from one another?

There are three main types of blood vessels in the body: arteries, veins, and capillaries.

• Arteries: These vessels carry blood away from the heart. They have thick, muscular walls to handle the high pressure of blood being pumped by the heart.

• Veins: These vessels carry blood back to the heart. They have thinner walls than arteries and often have valves to prevent blood from flowing backward.

• Capillaries: These are the smallest blood vessels. They connect arteries and veins and have thin walls to allow the exchange of oxygen, nutrients, and waste between blood and tissues.

How does resistance and blood pressure affect blood flow in the body?

Resistance and blood pressure are important factors that affect how blood flows in the body.

• Resistance: This is like friction that blood faces as it moves through vessels. More resistance makes it harder for blood to flow, similar to how it's harder to walk through mud than on a sidewalk.

• Blood Pressure: This is the force that pushes blood through the vessels. Higher blood pressure means blood can flow more easily, like how water flows faster through a hose when you turn up the pressure.

Together, if resistance is low and blood pressure is high, blood flows easily. If resistance is high and blood pressure is low, blood flow is slower.

How does resistance, heart rate, and stroke volume affect blood pressure in the body?

• Resistance: This is like the friction blood faces as it moves through the vessels. Higher resistance makes it harder for blood to flow, which can increase blood pressure.

• Heart Rate: This is how fast the heart beats. A faster heart rate means the heart is pumping more blood through the vessels in a shorter time, which can raise blood pressure.

• Stroke Volume: This is the amount of blood pumped by the heart in one beat. More blood pumped with each beat (higher stroke volume) means more blood is being pushed through the vessels, which can also increase blood pressure.

In simple terms, higher resistance, a faster heart rate, and a larger stroke volume can all lead to higher blood pressure.

How does blood pressure change as you move through the cardiovascular system?

Blood pressure is highest in the arteries right after the blood leaves the heart. As the blood moves through the smaller arteries and into the capillaries, the pressure gradually decreases. By the time the blood reaches the veins, the pressure is much lower. This gradual drop in pressure helps ensure that blood flows smoothly through the entire cardiovascular system.

How is blood pressure measured from the arm?

Blood pressure is measured from the arm using a device called a blood pressure cuff or sphygmomanometer. The cuff is wrapped around the upper arm and inflated to temporarily stop blood flow in the artery. Then, the cuff is slowly deflated while a healthcare provider listens with a stethoscope or uses a digital monitor to measure the pressure. The measurement gives two numbers: the higher number (systolic) measures the pressure when the heart beats, and the lower number (diastolic) measures the pressure when the heart is at rest.

What’s systolic, diastolic, and mean arterial pressure?

Systolic pressure is the higher number in a blood pressure reading; it measures the pressure in your arteries when your heart beats. Diastolic pressure is the lower number; it measures the pressure in your arteries when your heart is at rest between beats. Mean arterial pressure (MAP) is an average pressure in your arteries during one cardiac cycle, giving an overall idea of the pressure your organs are experiencing.

What is the connection between total cross-sectional surface and the speed of blood of our circulatory system?

The connection between total cross-sectional surface and the speed of blood in our circulatory system is simple: when the total cross-sectional area of the blood vessels increases, the speed of blood flow decreases. This happens because blood has to spread out over a larger area, like how water flows slower when it spreads over a wide, flat surface compared to a narrow stream

In our circulatory system, where is cross-sectional surface area the highest, and where is the speed of blood the slowest? The fastest?

The cross-sectional surface area is highest in the capillaries, which are the smallest blood vessels. Because the blood has to spread out over this large area, the speed of blood flow is the slowest in the capillaries. The speed of blood is the fastest in the arteries, where the cross-sectional area is smaller.

Why does blood flow through the veins and go back to the heart?

Blood flows through the veins and goes back to the heart because the heart needs to pump it again. The veins collect blood that has delivered oxygen and nutrients to the body’s tissues and return it to the heart. Once back in the back of the heart, the blood is sent to the lungs to pick up more oxygen and then pumped out to the rest of the body again.