Ch 22 - Lymphatic System

Question 1

Resistance

Answer 1

The ability to ward off the pathogens that produce disease

Question 2

Susceptibility

Answer 2

Lack of resistance

Question 3

Innate Immunity

(aka Nonspecific Resistance)

Answer 3

present at birth and includes defense mechanisms that provide general protection against invasion by a wide range of pathogens

Question 4

Immunity

(aka Adaptive Immunity)

Answer 4

involves activation of specific lymphocytes that combat a particular pathogen or other foreign substance

Question 5

Lymphatic System

Answer 5

• lymph
• lymphatic vessels
• several structures and organs that contain lymphatic tissue
• bone marrow

Question 6

Functions of the Lymphatic System

Answer 6

1. Drain excess interstitial fluid and return plasma proteins to the blood
2. Transport dietary fats
3. Carry out immune responses

Question 7

Lymphatic Vessels

Answer 7

• begin as lymph capillaries, which are closed on one end
• carry excess tissue fluid and plasma proteins
  
  • if fluids are not picked up by lymph vessels, edema occurs as fluid accumulates in tissues
• form a one-way system towards the heart

Question 8

Lymphatic Capillaries

Answer 8

• located between cells of many tissues
  
  • found throughout the body except in avascular tissue, the central nervous system, portions of the spleen, and red bone marrow
• merge to form lymphatic vessels
• have greater permeability than blood capillaries
• have a slightly larger diameter than blood capillaries
• have overlapping endothelial cells which work as one-way valves
• Anchoring filaments extend from the capillary and attach into endothelial cells

Question 9

Lacteal

Answer 9

specialized lymphatic capillaries, in the villus of the small intestine, that carry dietary lipids into lymphatic vessels and ultimately into the blood

Question 10

Chyle

Answer 10

lymph draining from the small intestine that contains dietary lipids and gives a creamy white appearance

(elsewhere in the body, lymph is a clear, pale-yellow fluid)

Question 11

Lymph Trunks and Ducts

Answer 11

From the lymphatic vessels, lymph passes through lymph nodes and then into lymph trunks

• Lumbar trunk
• Intestinal trunk
• Bronchomediastinal trunk
• Subclavian trunk
• Jugular trunk

Lymph trunks then merge to form either the thoracic duct or the right lymphatic duct

Question 12

Lumbar Trunk

Answer 12

drains lymph from lower limbs, wall and viscera of the pelvis, kidneys, adrenals, and abdominal wall

Question 13

Intestinal Trunk

Answer 13

drains lymph from the stomach, intestines, pancreas, spleen and part of the liver

Question 14

Bronchomediastinal Trunk

Answer 14

drains lymph from the thoracic wall, lung, and heart

Question 15

Subclavian Trunk

Answer 15

drains the upper limbs

Question 16

Jugular Trunk

Answer 16

drains the head and neck

Question 17

Thoracic Duct

Answer 17

• begins as a dilation called cisterna chyli
• receives blood from abdomen and lower extremities, left side of head, neck, and chest

Question 18

Right Lymphatic Duct

Answer 18

receives blood from upper right side of the body (right jugular, right subclavian, right bronchomediastinal trunks)

Question 19

Formation and Flow of Lymph

Answer 19

1. Interstitial fluid
2. Lymph capillaries
3. Lymph vessels
4. Lymph trunks
5. Lymph ducts
6. Junction of subclavian and jugular veins

Question 20

Aids of Lymph Flow

Answer 20

• skeletal muscle pump/contractions
• respiratory pump/inhalation
• smooth muscle in lymphatic walls contracting

Question 21

Primary Lymphatic Organs

Answer 21

Organs where immune cells become immunocompetent (capable of mounting an immune response) and where stem cells divide

• Red bone marrow (B cells)
• Thymus (T cells)

Question 22

Thymus Gland

Answer 22

• lies between the sternum and the heart
• bi-lobed organ consisting of an outer cortex and an inner medulla
• functions at peak levels only during childhood
• produces hormones (such as thymosin) to program lymphocytes
• site of T-cell maturation
  
  • immature T-cells migrate to the cortex and begin to mature
  • about 2% survive and then enter the medulla

Question 23

Secondary Lymphatic Organs

Answer 23

• Lymph nodes
  
  • 600 bean shaped nodes along lymphatic vessels, usually appear in groups
• Spleen
  
  • largest single mass of lymphatic tissue in the body
• Lymphatic nodules
  
  • egg shaped masses of lymphatic tissue not surrounded by a capsule