Spleen and Lymphoid Tissue Quiz

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Questions and Answers

What is the main function of NK cells in the immune system?

Releasing histamines to combat allergic reactions

Producing antibodies to neutralize pathogens

Facilitating the maturation of T cells

Inducing apoptosis in infected or cancerous cells (correct)

Which substance produced by NK cells is responsible for forming pores in the membranes of infected cells?

Granzyme

Perforin (correct)

Histamine

Cytokines

What role do eosinophils play in the inflammatory response?

Attracting more immune cells through cytokines (correct)

Directly killing virus-infected cells

Enhancing the production of antibodies by B cells

Producing interferons to inhibit viral replication

What ensures that antigen presenting cells are effective in linking innate and adaptive immunity?

Their presentation of antigens to T cells Signup and view all the answers

What is the primary mechanism by which NK cells kill target cells?

Induction of apoptosis through Fas ligand Signup and view all the answers

What is the primary function of the spleen?

Destruction of defective RBCs Signup and view all the answers

Where is the spleen located in the human body?

Lateral on the left side of the stomach Signup and view all the answers

What type of circulation does blood flow through the spleen during slow flow?

Open circulation Signup and view all the answers

What type of lymphatic tissue is specifically associated with mucous membranes?

MALT Signup and view all the answers

Which component of the spleen is primarily involved in immune function?

White pulp Signup and view all the answers

Which of the following best describes the red pulp of the spleen?

The site for old blood cell destruction Signup and view all the answers

What is the primary role of leukotrienes during the inflammatory stage?

To attract neutrophils to the site of inflammation. Signup and view all the answers

What are Peyer's patches an example of?

MALT Signup and view all the answers

What result does vasodilation and increased permeability have during inflammation?

Fluid influx leading to edema and pain. Signup and view all the answers

Which type of lymphoid tissue is specifically effective against inhaled pathogens?

BALT Signup and view all the answers

Which cells are primarily responsible for the initial response to infection during inflammation?

Neutrophils. Signup and view all the answers

What does a respiratory burst primarily involve?

Production of free radicals to kill bacteria. Signup and view all the answers

What is the function of the fibrin mesh formed during the inflammatory response?

To help in the repair of injured tissue. Signup and view all the answers

What distinguishes foreign antigens from self antigens?

Self antigens are produced by the body. Signup and view all the answers

What is the primary function of CD4 T cells?

To activate B cells and CD8 T cells. Signup and view all the answers

Which MHC class molecules are associated with activating CD8 T cells?

MHC class I molecules. Signup and view all the answers

Which of the following best describes antibody-mediated immunity?

Production of antibodies that bind to extracellular targets. Signup and view all the answers

What is a distinguishing feature of MHC class II molecules?

They are displayed only by antigen-presenting cells (APCs). Signup and view all the answers

Which cells are primarily responsible for producing antibodies?

Plasma cells. Signup and view all the answers

What type of antigens do CD8 T cells recognize?

Endogenous antigens displayed by MHC class I molecules. Signup and view all the answers

Which of the following components are involved in cell-mediated immunity?

Cytotoxic T cells and Helper T cells. Signup and view all the answers

What is NOT a function of the nose?

Routes food into the digestive system Signup and view all the answers

Which structure forms the posterior portion of the nasal septum?

Vomer bone Signup and view all the answers

What function do the nasal conchae serve?

Enhance air turbulence and filtration Signup and view all the answers

Which is NOT a region of the pharynx?

Metapharynx Signup and view all the answers

What epithelium lines the oropharynx?

Stratified squamous epithelium Signup and view all the answers

What is the primary function of the epiglottis?

Cover the larynx inlet during swallowing Signup and view all the answers

Which part of the trachea is particularly sensitive and can trigger coughing?

Carina Signup and view all the answers

What is the primary function of the bronchi and bronchioles in the respiratory system?

Change diameter to regulate airflow Signup and view all the answers

Which part of the larynx is also known as the voice box?

Larynx Signup and view all the answers

Which mucous membranes components help to defend the respiratory system?

All of the above Signup and view all the answers

How many primary bronchi are formed by the division of the trachea?

Two Signup and view all the answers

What is the role of the vestibular folds in the larynx?

Close the glottis during swallowing Signup and view all the answers

Which of the following bones does NOT contribute to the formation of the paranasal sinuses?

Temporal Signup and view all the answers

Study Notes

Spleen

Largest lymphoid organ, about the size of a fist
Located on the left side of the stomach
Supplied by splenic artery and vein, entering and exiting at the hilum
Encased by fibrous capsule with trabeculae
Functions:
- Destroys defective red blood cells (RBCs)
- Detects and responds to foreign substances
- Acts as a limited reservoir for blood
Blood flows through three different rates:
- Slow flow through open circulation
- White pulp:
  - Primarily responsible for immune function
  - Surrounds central arteriole
  - Contains B and T cells
- Red pulp:
  - Destroys old blood cells and bloodborne pathogens
  - Contains reticular fibers
  - Macrophages engulf RBCs

Lymphoid Tissue

MALT (Mucosa-associated lymphoid tissue):
- Lymphoid tissues associated with mucous membranes, including:
  - Tonsils
  - Peyer's Patches
  - Appendix
BALT (Bronchus-associated lymphoid tissue):
- Effective against inhaled pathogens

Tonsils

Large groups of lymphatic nodules in the nasopharynx and oral cavity
Antigen-presenting cells (APCs):
- Present antigens to T cells in lymph nodes
- Most effective presenters, linking innate and adaptive immunity
NK cells:
- Function in immunological surveillance of blood and lymph
- Attack cells lacking "self" cell-surface receptors (MHC1)
- Induce apoptosis (cell death) in cancer and virus-infected cells
- Attach to cells via activation receptor (Fas ligand) and send apoptotic signals
- Secrete chemicals:
  - Perforin: Forms pores in infected cell membranes
  - Granzyme: Protein-digesting enzyme

Eosinophils

Attracted to site by T cell cytokines
Involved in mast cell degranulation (inflammation) and fluid leakage
Increase local vascular permeability, potentially flushing action

Inflammatory Response

Stages:
- Tissue injury:
  - Inflammatory chemical release
  - Chemicals released:
    - Histamine
    - Leukotrienes
    - Prostaglandins
  - Effects:
    - Vasodilation
    - Leaky capillaries
    - Leukocyte attraction to area
- Vasodilation and increased permeability:
  - Blood flow to area increases
  - Fluid containing clotting factors and antibodies flood area (edema)
  - Fluid sweeps foreign material into lymphatic vessels
  - Clotting factors form fibrin mesh, initiating repair
  - Pressure on nerve endings causes pain
- Phagocyte mobilization:
  - Leukotrienes attract neutrophils
  - Neutrophils arrive first, followed by macrophages
  - Phagocytes and pathogens die, accumulating as pus
  - Complement proteins activated if pathogen involved
  - Adaptive immunity elements arrive

Respiratory Burst

Triggered by Helper T cells
Rapid release of free radicals or reactive oxygen species (ROS)
Increases pH and osmolarity, killing bacteria

Antigen

Substance that causes the body to make an immune response against it

Antigen Groups - Foreign and Self

Foreign:
- Not produced by the body
- Introduced from the outside
- Examples: Bacteria, viruses, other microorganisms causing disease, pollen, animal dander, mite feces, foods, drugs
Self:
- Produced by the body

Lymphocyte Development and Activation

Origin: B cells and T cells originate from hematopoietic stem cells in bone marrow
Development:
- T cells mature in the thymus
- B cells mature in bone marrow
Activation: B and T cells become activated in response to specific antigens
Proliferation: Activated lymphocytes proliferate to produce a large number of effector cells

Cells that Recognize Antigens

CD4 (Helper T cells):
- Recognize antigens presented by MHC class II molecules
CD8 (Cytotoxic T cells):
- Recognize antigens presented by MHC class I molecules

Major Histocompatibility Complex (MHC) Molecules

Group of self-proteins unique to each individual
Groove on MHC molecule holds self-antigen or foreign antigen
Association of antigen and MHC occurs inside the cell
T cells recognize antigens presented on MHC proteins

MHC Class I and MHC Class II Molecules

MHC Class I:
- Displayed by all cells except RBCs
- Present endogenous antigens (viruses, parasites, bacteria that replicate inside the cell)
- Activate CD8 T cells
MHC Class II:
- Displayed by APCs (dendritic cells, macrophages, B cells)
- Present exogenous antigens (pathogens found outside cells)
- Activate CD4 T cells

Antibody-mediated Immunity

Humoral immunity involving antibodies produced by B cells
Antibodies bind to target cells, targeting extracellular targets
Cells involved:
- B cells
- Plasma cells
- Memory B cells
- Helper T cells (CD4)
- Dendritic cells
- Macrophages

Cell-mediated Immunity

Involves T cells directly attacking target cells
Targets intracellular targets

Nose and Paranasal Sinuses

Nose:
- Only the external portion of the respiratory system
- Functions:
  - Provides an airway
  - Moistens and warms air
  - Filters and cleans air
  - Resonating chamber for speech
  - Houses olfactory receptors
- Structures:
  - Root: Area between eyebrows
  - Bridge and Dorsum nasi: Anterior margin
  - Apex: Tip of the nose
  - Alae: Lateral boundary
Nasal Cavity:
- Formed by nasal and frontal bones superiorly
- Formed by maxillary bones laterally
- Plates of hyaline cartilage
- Divided by the nasal septum:
  - Anteriorly: Septal cartilage
  - Posteriorly: Vomer bone and perpendicular plate
- Posterior nasal opening: Connects nasal cavity to nasopharynx
- Nasal vestibule: Superior to nostrils, lined with hairs that filter coarse particles
- Mucous membranes: Contain lysozyme and defensins, ciliated cells sweep mucus towards throat, inhaled air is warmed by capillaries, mucosa contains sensory nerve endings that trigger sneezing reflex
- Nasal conchae:
  - Mucosa-covered projections: Superior, middle, and inferior conchae
  - Function to:
    - Increase mucosal area
    - Enhance air turbulence
    - Filter, heat, and moisten incoming air
    - Reclaim heat and moisture
Paranasal sinuses:
- Cavities surrounding nasal cavity in:
  - Frontal, sphenoid, ethmoid, and maxillary bones
- Functions:
  - Lighten the skull
  - Secrete mucus
  - Help warm and moisten air

The Pharynx

Muscular tube ("throat")
Connects nasal cavity and mouth to larynx and esophagus
Composed of skeletal muscle
Three regions:
- Nasopharynx
- Oropharynx
- Laryngopharynx
Common opening for digestive and respiratory systems
Nasopharynx:
- Lies posterior to nasal cavity
- Lined with pseudostratified columnar epithelium with goblet cells
- Allows for passage of mucous debris
- Uvula closes nasopharynx during swallowing
- Pharyngeal tonsils (adenoids) located on posterior wall
- Auditory (eustachian) tubes drain and equalize pressure from middle ear, opening into lateral walls
Oropharynx:
- Shared with the digestive system
- Lined with most stratified squamous epithelium
- Passageway for food and air
- Fauces: Opening connecting oral cavity and pharynx
- Palatine tonsils on lateral walls of fauces
- Lingual tonsil on posterior surface of tongue
Laryngopharynx:
- Passageway for food and air
- Lined with stratified squamous epithelium
- Posterior to epiglottis
- Extends to larynx (anteriorly) and esophagus (posteriorly)

The Larynx

"Voice box"
Attached to the hyoid bone
Composed of 8 hyaline cartilages and 1 elastic cartilage (epiglottis)
Home of the vocal cords
Continuous with the trachea
Thyroid cartilage:
- Large, shield-shaped cartilage
- Laryngeal prominence (Adam's apple)
Epiglottis:
- Attached to thyroid cartilage
- Covers larynx inlet during swallowing
- Covered in taste bud-containing mucosa
Functions of larynx:
- Provides patent (open and unobstructed) airway
- Routes air and food into proper vessels
- Voice production
Vocal folds:
- Glottis: Folds and opening between vocal folds
- True vocal cords: Elastic fibers that fold to form vocal folds, vibrate to produce sound
- Vestibular folds: False vocal cords, close the glottis during swallowing

The Trachea

"Windpipe"
Composed of C-shaped hyaline cartilage rings connected by smooth muscle (trachealis)
Trachealis:
- Smooth muscle fibers connecting posterior parts of cartilage rings
- Contracts during coughing
Carina:
- Last tracheal cartilage branching into two main bronchi
- Mucosa of carina is highly sensitive, causing violent coughing if foreign objects make contact

The Bronchi and Subdivisions

Bronchial tree:
- Trachea divides into right and left primary bronchi
- Branches into lobar bronchi (3 on right, 2 on left)
Bronchi and bronchioles:
- Capable of changing diameter:
  - Bronchodilation: Smooth muscle relaxes, decreasing resistance and increasing airflow.
  - Bronchoconstriction: Smooth muscle contracts, increasing resistance and decreasing airflow

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Description

Test your knowledge about the spleen, the largest lymphoid organ, and the different types of lymphoid tissues. This quiz covers their structure, functions, and the immune response associated with them. Perfect for students studying anatomy or biology.