Circulation Overview

Question 1

What is the function of the circulation system?

Answer 1

Functions to transfer materials between external environment and internal cellular spaces

Consists of cardiovascular and lymphatic systems

Question 2

What is the cardiovascular system?

Answer 2

Heart and blood vessels (arteries, capillaries, veins)

Question 3

What is the lymphatic system?

Answer 3

Collects fluid from tissue spaces and returns it to the venous circulation

Question 4

What is the function of the pulmonary circulation?

Answer 4

Pumps low oxygen blood from right bentricle to lungs through pulmonary arteries

Question 5

What is the function of the systemic circulation?

Answer 5

Pumps oxygen-rich blood from the left ventricle to the body through the aorta

Question 6

Describe the pathway of blood starting with the RA.

Answer 6

RA –> RV –> Pulm. Arteries –> Lung capillaries –> Pulm. Veins –> LA –> LV –> Aorta +systemic arteries –> Systemic capillaries –> Systemic veins –> Vena Cavae –>

Question 7

What are arteries?

Answer 7

Carry oxygen-rich blood under relatively high pressure from the heart to all parts of the body

Question 8

What are Veins?

Answer 8

Return low-oxygen blood to heart, carry blood under lower pressure than arteries (except pulmonary veins)

Question 9

What are capillaries?

Answer 9

Connect arterial and venous circulation for nutrient, oxygen, and waste exchange

Question 10

What is the tunica adventitia?

Answer 10

Vessel outer connective tissue latyer

Question 11

What is the tunica media?

Answer 11

Middle smooth muscle layer, most variable in thickness and amount of elastic fibers

Controls vessel constriction

Question 12

What is the tunica intima?

Answer 12

Inner lining of endothelial cells supported by delicate connective tissue

Question 13

What are Large, conducting arteries?

Answer 13

Receive initial cardiac output

Many layers of elastic fibers in TM to allow expansion and recoil during the cardiac cycle

Helps maintain constant flow of blood and minimizes changes in BP

E.g. aorta, pulmonary trunk

Question 14

What are medium, distributing muscular arteries?

Answer 14

Composed primarily of smooth muscle in TM

Muscle wall allows vessels to decrease their diameter and regulate blood flow to different parts of the body

E.g. most of the named arteries

Question 15

What are small arteries and arterioles?

Answer 15

Narrow lumina and thick muscular walls

Arteriole smooth muscles control the filling of capillary beds and regulate the arterial pressure in teh vascular system

These can result in hypertension if the muscle tonus is above normal

Question 16

What is atherosclerosis?

Answer 16

Common form of arteriosclerosis associated with fat and cholesterol buildup - may result in thrombus

Question 17

What are anastomoses?

Answer 17

Communications (connections) between branches of arteries

Question 18

What are collateral vessels?

Answer 18

Series of smaller vessels that supply a tissue in addition to its main blood supply

Question 19

What are end arteries?

Answer 19

Do not have functional anastomoses

Blockage interrupts tissue perfusion, usually results in tissue necrosis after occlusion

Question 20

What are venules and small veins?

Answer 20

Smallest unnamed veins that drain capillaries

Venules join to form small veins, which empty into larger veins and unite to form venous plexuses

Question 21

What is a medium vein?

Answer 21

Drain venous plexuses and accompany medium arteries

Have valves that permit blood flow towards the heart but prevent back flow

E.g. named superficial veins of upper and lower limbs

Question 22

What are accompanying veins?

Answer 22

Occur as multiple vessels in a common vascular sheath with an artery

Question 23

What are large veins?

Answer 23

Contain smooth muscle and a well-developed tunica adventitia

Question 24

What are capillaries?

Answer 24

Continuous vessels that connect arterioles and venules

Question 25

What is a portal venous system?

Answer 25

Venous system that links two capillary beds

E.g. hepatic portal system drains blood from the digestive tract into the liver

Question 26

What does the lymphatic system transport?

Answer 26

Large proteins that cannot pass through systemic capillaries

E.g. cellular debris, pathogens

Question 27

What are lymphatic capillaries?

Answer 27

Network of blind (closed) tubes that originate in the cellular spaces of tissues; lack a basement membrane so fluid, proteins, bacteria, and cells can enter easily

Question 28

What are lymphatic vessels?

Answer 28

Network of thin-walled, valve-containing vessels taht occur throughout the body

Question 29

What is lymph?

Answer 29

Clear, yellowish fluid that is transported in lymph vessels

Question 30

What are lymph nodes?

Answer 30

Filter lymph on its way back to the venous system

Question 31

Where is most of the lymph drained?

Answer 31

Thoracic duct on the left side of the body

The upper right body is drained through the lymphatic duct