Lecture 13: Lymphatics

Question 1

What is the lymphatic system?

Answer 1

Network of vessels, tissues and organs that assist in body fluid circulation and defend the body of pathogens

Question 2

What is the lymphatic system composed of?

Answer 2

• *Lymph**
• *Lymphatic vessels**
• Capillaries, vessels, trunks, ducts

Lymphoid organs and tissues

• Primary- Red bone marrow , thymus*
• Secondary- Spleen, lymph nodes, lymphatic nodule*s

Question 3

What is the function of the lymphatic system?

Answer 3

• Drain excess interstitial fluid
• Transport dietary lipids and lipid soluble vitamins
  
  • Carry out immune response

Question 4

How is lymph produced?

Answer 4

Fluid found in interstitial space around capillaries

Fluid returned back into circulation by lymphatic vessels as lymph

LACTEALS are found in GIT and transfer lipids

Question 5

Describe lymphatic vessels

Answer 5

• Thin walled
• Similar to structure to veins
• have valves
  
  • Lymph nodes along lymphatic vessels

Question 6

Identify and describe the function of the lymphatic trunks

Answer 6

Lumbar trunk: collect lymph from lower limbs and lower pelvis

Intestinal trunk: receive lipids rather than lymph from GIT

Broncho-mediastinal trunk: receives lymph from thoracic cavity

subclavian trunk: receives lymph from upper limbs

Jugular trunk : receives lymph from head and neck

LUMBAR + INTESTINAL DRAIN INTO CISTERNA CHYLII BELOW DIAPHRAGM AND CONTINUE AS THORACIC DUCT

Question 7

What are your lymphatic ducts and what do they drain?`

Answer 7

• Thoracic Duct- Begins at cisterna chyli, enters thoracic cavity through the aortic opening and ascend within thorax. DRAINS LYMPH FROM LOWER LIMBS AND LEFT HAND SIDE OF THE UPPER BODY
• Right lymphatics duct - DRAIN LYMPH FROM UPPER RIGHT HAND SIDE OF BODY

Question 8

how much lymph do we produce daily?

Answer 8

3 litres

Question 9

Outline the flow of lymph circulation:

Answer 9

interstitial fluid → lymph

lymphatic capillaries → lymphatic vessels → lymphatic ducts → lymphatic trunk → lymphatic duct → veins

Question 10

How is lymph pushed around the body?

Answer 10

skeletal muscle pump and respiratory pump

Question 11

Identify a primary lymphatic organ responsible for the main production of haematopoiesis.

Answer 11

• Red bone marrow
  
  • FUNCTION - B lymphocytes mature in bone marrow while T lymphocytes migrate to thymus to mature and become immunocompetent.

Question 12

Identify a primary lymphoid organ that is fully functional at birth:

Answer 12

Thymus: bilobed organ in superior mediastinum

site of T Lymphocyte maturation with a rich blood supply

Question 13

Identify the parts of the thymic lobule:

Answer 13

Cortex: dark zone which is the site of maturation for T cells. (most die through apoptosis)

Medulla: light zone mature T-Cells

Hassall’s corpuscles: epithelial cells become filled with keratin, degenerate and calcify

Question 14

What region is the spleen located in?

Answer 14

left hypochondrium

Question 15

Classify the parenchyma of the spleen

Answer 15

White pulp; lymphatic tissue around the branches of splenic artery.

red pulp: venous sinuses and chords of splenic tissue

FUNCTION: mounts primary immune response, breaks down old cells, storage of platelets NOT ESSENTIAL FOR LIFE

Question 16

Describe lymph nodes

Answer 16

Encapsulated clusters of lymphoid tissue located along the pathway of lymphatic vessels. more concentrated amounts in axial, mesenteries and inguinal region.

Function: Serve as filters widely distributed throughout body

Question 17

The interior of the LYMPH NODE can be divided into the…

Answer 17

outer cortex and inner medulla

between the cortex and medulla the zone contains mostly t lymphocytes.

Question 18

Outline the flow of lymph through the lymph node:

Answer 18

Afferent lymphatic vessels → subcapsular sinus → trabecular sinuses → medullary sinuses → efferent lymph vessel (hilum)

Question 19

What is a lymphatic nodule? give examples:

Answer 19

Small egg-shaped masses of lymphatic tissue without capsule.

Question 20

identify your tonsils

Answer 20

Adenoid

Tubal

Palatine

Lingual