The lymphatic system

Question 1

What is the structure of the lymphatic system

Answer 1

The lymphatic system is second to the circulatory system which runs parallel to the cardiovascular system and carries lymph. It is made up of lymph vessels, lymph nodes, the spleen and thymus glands

Question 2

What are the functions of the lymphatic system

Answer 2

Tissue drainage
Fat transport
Trapping foreign material

Question 3

What are the types of lymph nodes

Answer 3

The cervical lymph nodes in the neck, the axial lymph nodes in the armpit and the inguinal lymph nodes in the groin

Question 4

What are the mechanical defences of the immune system

Answer 4

The skin, the mucocilliary escalator and the mucous membranes

Question 5

How does the skin defend against disease

Answer 5

The epidermis acts as a mechanical barrier which also continuously flakes away taking the pathogen’s with it. The dense keratin layer also acts as a barrier.

Question 6

How does the mucocilliary escalator defend against disease

Answer 6

The mucocilliary escalator contains goblet cells that secrete mucus and ciliated epithelium which waft particles to the stomach.

Question 7

How does the mucous membranes defend against disease

Answer 7

The mucous membranes line cavities and are rich in goblet cells that produce mucus.

Question 8

What are the chemical defenses

Answer 8

Hcl, lactobacillus, lysozmes

Question 9

How does HCl defend against disease

Answer 9

HCl increases the acidity of the stomach to sterilise food, and also sterilises the mucus from the lungs

Question 10

How does lactobacillius defend against disease

Answer 10

Lactobacillius is found in the female reproductive tract and produces lactic acid which lowers the pH and stops bacteria colonising

Question 11

Why do pregnant women get swollen ankles

Answer 11

In pregnancy the uterus compresses lymph vessels causing a building of fluid in the legs which causes swelling

Question 12

What is dysbiosis

Answer 12

Dysbiosis is when the lactobacillius are wiped out by strong soaps or antibiotics which allows pathogenic yeast to grow and cause infection eg thrush

Question 13

What are the cellular defenses

Answer 13

Eosinophils, Basophils, Neutrophils, monocytes and lymphocytes

Question 14

How does eosinophils defend against disease

Answer 14

Eosinophils destroy parasites by releasing enzymes onto the integument

Question 15

How do basophils defend against disease

Answer 15

Basophils are the rarest white blood cells which produce heparin (anticoagulant) and histamine (mediator of inflammation)

Question 16

How do Neutrophils defend against disease

Answer 16

Neutrophils trap pathogens by phagocytosis

Question 17

How do monocytes defend against disease

Answer 17

Monocytes mature into macrophages which trap pathogens

Question 18

How do lymphocytes defend against disease

Answer 18

Lymphocytes produce antibodies

Question 19

What is inflammation

Answer 19

Inflammation is the normal response to irritation, infection or injury

Question 20

How does the inflammatory response work

Answer 20

Pain receptors are stimulated
The area turns red and hot as blood flow increases
It also becomes swollen due to fluid accumulation
This removes pathogenic material and limits the spread of infection

Question 21

What are mast cells

Answer 21

Mast cells synthesise ad store histamine which initiates the inflammatory response

Question 22

Explain the stages of the immune response

Answer 22

1) the mechanical barrier is damaged
2) Bacteria is introduced and divides rapidly
3) Mast cells release histamine
4) Histamine initiates vasodilation which increases blood flow
5) neutrophils trap & remove bacteria