Circulatory Systems - Lecture 6

Question 1

What are the two main types of blood circulatory systems?

Answer 1

Systemic and Pulmonary

Question 2

What are the main substances transported by the circulatory system?

Answer 2

○ O2 (carried by RBCs)
○ Nutrients
○ CO2
○ Metabolic waste
○ Cells of the immune system (WBCs)
○ Hormones

Question 3

Describe the general structure of the blood circulatory system

Answer 3

Closed circuit consisting of arteries, veins and capillaries

Question 4

Describe the systemic circulation

Answer 4

The systemic circulation is a high pressure system that:
○ Carries oxygen-rich blood from the left side of the heart to the body tissues
○ Returns oxygen-poor blood from the tissues to the right side of the heart

Question 5

Give examples of arteries in the systemic circulation and where they are found

Answer 5

○ Aortic arch - The main artery leaving the heart, curving upwards from the left ventricle.
○ Brachial - Found in the upper arm.
○ Radial - Located in the forearm, on the thumb side.
○ Ulnar - Located in the forearm, on the pinky side.
○ Femoral - Found in the thigh.
○ Popliteal - Located behind the knee.
○ Posterior tibial - Located in the lower leg, near the ankle.
○ Common carotid - Found in the neck.
○ Aorta - The largest artery in the body, extending from the heart.
○ Dorsalis pedis - Found on the top of the foot

Question 6

Give examples of veins in the systemic circulation and where they are found

Answer 6

○ Superior vena cava - A large vein returning blood from the upper body to the right atrium of the heart.
○ Internal jugular - Located in the neck, draining blood from the head and neck.
○ Inferior vena cava - A large vein returning blood from the lower body to the right atrium of the heart.
○ Brachiocephalic - A vein in the upper chest, formed by the joining of the internal jugular and subclavian veins

Question 7

How is heart rate measured using arteries?

Answer 7

Heart rate can be measured by feeling the pulse in various arteries such as the:
○ Radial
○ Carotid
○ Brachial
○ Femoral
○ Popliteal
○ Posterior tibial
○ Dorsalis pedis

Question 8

Describe the pulmonary circulation

Answer 8

The pulmonary circulation is a low pressure system that:
○ Carries oxygen-poor blood from the right side of the heart to the lungs
○ Returns oxygen-rich blood from the lungs to the left side of the heart

Question 9

What is unusual about the pulmonary arteries?

Answer 9

Pulmonary arteries carry blood away from the heart but are oxygen-poor

Question 10

What is unusual about the pulmonary veins?

Answer 10

Pulmonary veins carry blood towards the heart but are oxygen-rich

Question 11

What are the main components of the lymphatic system?

Answer 11

○ Network of lymph vessels
○ Lymph
○ Lymphatic tissues and organs

Question 12

What are the functions of the lymphatic system?

Answer 12

○ The body’s defence mechanisms
○ Providing a mechanism for the drainage of interstitial fluid

Question 13

What is interstitial fluid?

Answer 13

○ In the capillary the fluid is called plasma, in the interstitial space it is called interstitial fluid
○ Fluid moves from the arterial end of the capillary into the interstitial space
○ Fluid moves from the interstitial space back into the capillary at the venous end

Question 14

What is capillary blood pressure (CPB) and what does it do?

Answer 14

○ Pushes fluid out of the capillary into the interstitial fluid
○ This process is called filtration and takes nutrients and gases
○ CPB decreases with progression along the capillary

Question 15

What is blood colloid osmotic pressure (BCOP) and what does it do?

Answer 15

○ Pulls fluid back into the capillary
○ This process is called reabsorption and brings wastes and gases
○ BCOP is mainly due to plasma proteins and remains constant

Question 16

Describe capillary exchange at the arterial end

Answer 16

○ CBP is greater than BCOP
○ This results in filtration

Question 17

Describe capillary exchange at the venous end

Answer 17

○ BCOP is greater than CBP
○ This results in reabsorption

Question 18

What percentage of fluid is reabsorbed at the venous end of the capillary?

Answer 18

~85%

Question 19

What happens to the remaining 15% of fluid not reabsorbed at the venous end of the capillary?

Answer 19

○ Must be removed from the interstitial space, otherwise oedema will result
○ Is picked up by the lymphatic capillaries

Question 20

How does excess interstitial fluid enter the lymphatic system?

Answer 20

○ Lymph capillaries are blind-ended tubes located adjacent to capillary beds
○ The excess interstitial fluid enters the lymphatic capillary and is then called lymph

Question 21

Describe the pathway of lymphatic drainage

Answer 21

Lymph capillaries -> lymph vessels -> lymph nodes -> lymph trunks -> thoracic duct or right lymphatic duct

Question 22

Which part of the body does the right lymphatic duct drain?

Answer 22

○ The right side of the head and thorax
○ The right upper limb
○ Lymph re-enters in the right subclavian vein

Question 23

Which part of the body does the thoracic duct drain?

Answer 23

○ The thoracic duct drains lymph from the remainder of the body
○ Lymph re-enters in the left subclavian vein