Visual Anatomy and Physiology - Capillaries & Lymphatics

Questions and Answers

Which type of capillary is characterized by having small openings that allow for the exchange of larger molecules such as hormones and nutrients?

Muscle Capillary

Sinusoidal Capillary

Fenestrated Capillary (correct)

Continuous Capillary

What is the approximate diameter of a continuous capillary?

8-10µm (correct)

20-25µm

30-40µm

5-7µm

Which type of capillary is primarily found in the liver, allowing for the passage of blood cells and large proteins?

Fenestrated Capillary

Vascular Capillary

Continuous Capillary

Sinusoidal Capillary (correct)

What is the primary function of the lymph vascular system?

Act as a drainage system and transport lymph Signup and view all the answers

Which type of capillary allows for minimal diffusion of materials due to its tightly joined endothelial cells?

Continuous Capillary Signup and view all the answers

Which of the following characteristics is NOT associated with fenestrated capillaries?

High permeability to large molecules Signup and view all the answers

What is the diameter range of sinusoidal capillaries?

30-40µm Signup and view all the answers

Which type of capillary is primarily located in skeletal and cardiac muscle tissues?

Continuous Capillary Signup and view all the answers

What is one of the primary functions of the lymphatic system?

Drains excess tissue fluid and plasma proteins Signup and view all the answers

What type of lymphatic vessel is responsible for draining fat-laden lymph from the small intestine?

Lacteals Signup and view all the answers

What structural feature helps prevent backflow in larger collecting lymphatic vessels?

Valves Signup and view all the answers

Which statement about lymphatic capillaries is true?

They are blind ending Signup and view all the answers

How does the lymphatic system respond to foreign antigens?

By releasing antibodies and activated immune cells Signup and view all the answers

What is the cisterna chyli?

A major lymph collecting vessel Signup and view all the answers

Which of the following is NOT a characteristic of lymph vessels?

Presence of RBCs Signup and view all the answers

What is the main role of lymphatic filters in the body?

To filter foreign material from the lymph Signup and view all the answers

What is the primary function of capillaries in the circulatory system?

Site of nutrient and gas exchange between blood and tissues Signup and view all the answers

Which structural feature of capillaries contributes to their function as exchange sites?

Very thin walls enhancing diffusion Signup and view all the answers

Which type of capillary is characterized by its leaky structure?

Fenestrated capillaries Signup and view all the answers

How do precapillary sphincters regulate blood flow through capillaries?

By controlling the contraction of smooth muscle cells Signup and view all the answers

Which characteristic is true of sinusoidal capillaries?

They allow for the passage of large molecules and cells Signup and view all the answers

What factor leads to slower blood flow in capillary beds compared to arterioles?

Large total cross-sectional area of the capillary bed Signup and view all the answers

Where are continuous capillaries predominantly found in the body?

In the brain and muscles Signup and view all the answers

What type of tissue primarily composes the walls of capillaries?

Epithelial tissue Signup and view all the answers

Study Notes

Capillaries

Capillaries enable exchange between blood and tissues through very thin walls, large total cross-sectional area, and slow, smooth blood flow.
The total cross-sectional area of capillary beds is significantly larger than arterioles, leading to decreased blood flow velocity.
Capillaries come in three types based on the rate and control of exchange:
- Continuous capillaries: Most common type, with an 8-10 µm diameter. Found in skeletal and cardiac muscle.
- Fenestrated capillaries: More permeable, also with an 8-10 µm diameter, commonly located in the kidneys and small intestine.
- Sinusoidal capillaries: Very leaky, 30-40 µm diameter, primarily found in the liver.
Precapillary sphincters, made of smooth muscle cells, regulate blood flow into capillary beds via vascular shunts.

Lymphatic System

The lymphatic system functions as an open-entry drainage system, essential for maintaining fluid balance and immune response.
Primary functions include:
- Draining excess tissue fluid and plasma proteins, returning them to the bloodstream.
- Filtering foreign materials from lymph.
- Screening for antigens and activating immune responses by producing antibodies and immune cells.
- Absorbing fats from the intestine and transporting them to the blood.
Lymphatic vessels begin as large blind-end capillaries and collect lymph fluid. Special lymphatic vessels called lacteals transport fat-laden lymph from the small intestine to the cisterna chyli.
Larger lymphatic vessels contain valves that prevent backflow, ensuring unidirectional lymph flow.
Regional lymph nodes filter lymph and help mount immune responses against pathogens.

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Description

This quiz covers key concepts from Martini et al.'s Visual Anatomy and Physiology, focusing on the structure and function of capillaries and the lymphatic system. Students will explore the exchange mechanisms in capillaries and the role of lymph nodes in immune response.