Immune System

Question 1

T-lymphocyte

(Intestinal Epithelium)

Question 2

Identify the following:

B-lymphocyte

Plasma Cell

Reticular Cell

Lymphoblast

Answer 2

Question 3

Identify the following:

Lymphoblast

Lymphoblast in Mitosis

Answer 3

Question 4

Identify the following:

Lymphocyte

Answer 4

Much smaller than a lymphoblast

Located in the Mantle Zone

Question 5

What unique feature can be seen in this simple columnar epithelium?

Answer 5

M-cells:

• Pocket containing lymphatic cells
• B-cells
• T-cells
• Macrophages
• Dendritic cells

Located in the epithelium

Question 6

Identify a lymphatic nodule in this Rabbit secum

Answer 6

Question 7

Identify a lymphatic vessel. What is this typically composed of?

Answer 7

Carries filtered lymph away from diffuse lymphatic tissue to lymph nodes

ex. Tonsils

Question 8

What is going on in this stratified squamous epithelium?

Answer 8

White blood cells are migrating into the epithelium

Question 9

What is this cell and how can you tell?

Answer 9

Plasma cell:

• Clock face
• Pink Cytoplasm

Question 10

Identify the outlined zones in the lymphatic nodule

Answer 10

Germinal center:

• Has immature proliferating lymphocytes
• B-lymphoblasts (in this case)
• Lighter staining
  
  • B-lymphoblasts are euchromatic

Mantle Zone:

• Filled with b-lymphocytes
  
  • These are in a period of inactivity

Question 11

Identify the circled cell:

Answer 11

Tingible Body Macrophage:

• Phagocytize and digest unwated T-cells
• Consist of a larger, irregular shaped nucleus
• Found in cortico-medullary junction

Question 12

What is so special about the circled blood vessel?

Answer 12

HEV

These are specialized blood vessels

• Only found in the medulla of the thymus

The epithelial cells surrounding the blood vessel are rounder and not as flat

This is the location where mature T-cells can easily pass through the epithelium and enter the bloodstream.

Question 13

Identify a thymic corpuscle.

Where are they found in the thymus?

Answer 13

Found in the medulla of the thymus

Question 14

What is going on with the T-cell circled?

Answer 14

Mitotic Division

Question 15

How would you identify the T-lymphocytes in the cortex?

Answer 15

Small, circular cells

Darkly stained nucleus

Heterochromatic

Question 16

Identify the epithelial cells surrounding the blood vessel that is part of the blood/brain barrier.

Answer 16

Blood-Thymus Barrier=

Epithelioreticular cells + Endothelial cells + Pericytes

Question 17

Identify the following cells in the Thymus.

Answer 17

Nursing cells in the Thymus

They support T-cells

Question 18

Identify a Thymic Lobule

Answer 18

Question 19

Identify the following circled cells:

Answer 19

Plasma cell: Clock-face appearance

T-lymphocyte: Capable of migrating into epithelium

Question 20

Innate Immune Response

Answer 20

Goal = immediately prevent the spread and movement of foreign pathogens throughout the body

• First line of defense against invading pathogens
• Very quick response time
  
  • first critical hours after exposure to a new pathogen
• Needed until the adaptive immune response is ready

Components:

• Epithelial surfaces
  
  • Only one not found in the bloodstream

Phagocytitic cells:

• Macrophages
• Dendritic cells
• Natural killer cells
• Complement systems (not cells)

The nature of the immune response depends on the type of infection

Question 21

Adaptive Immune Response

Answer 21

• 24 hours post infection
• Works together with the innate immune response

Adaptive Immune Response Requires:

T-lymphocytes

B-lymphocytes

Plasma cells

• Activated b-lymphocytes

Antigen presenting cells

Question 22

The Innate Immune Response is dependent on

Epithelial Surfaces (1)

Answer 22

• Prevent the entry of pathogens
  
  • Nose & trachea
  • Pathogens stick to the mucous
  • Skin

Question 23

Simple Epithelium

Innate Immune Response

Answer 23

• Large number of immune cells directly under the the basement membrane
  
  • Only have basement membrane + 1 layer of cells
  • Conditions allow for pathogens to penetrate with ease
  • T-lyphocytes
  • Plasma cells (activated B-lymphocytes)

Reason behind why there is a vast number of immune cells ready to mount a response to a possible infection

Question 24

Stratified Cornified Epithelium

(Skin)

Innate Immune Response

Answer 24

Close contact with external environment

Physical barrier to entry

“Cornified” referring to the most superficial layer of cells lacking nuclei and having a squamous shape

• Filled with keratin protein