Chapter 22 - The Lymphatic System and Immunity Flashcards
What is Disease Resistance?
1- Nonspecific Resistance (Innate Immunity):
Present at birth and includes defense mechanisms that provide general protection against invasion by a wide range of pathogens
2- Immunity (Adaptive Immunity):
Involves activation of specific lymphocytes that combat particular pathogen or other foreign substance
The body system that carries out Immunes Responses is the Lymphatic System
What is Lymphatic System?
Lymphatic System consists of several structures and organs that contain:
1- Lymphatic Tissue
2- Bone Marrow
3- Lymph:
Fluid that flows within Lymphatic Vessels
What are the Functions of the Lymphatic System?
The Lymphatic System functions are:
1- Drain interstitial fluid
2- Transport dietary fats
3- Carry out Immune Responses
What is Lymphatic Vessels and Capillaries?
1- Lymphatic Vessels
Begin as Lymphatic Capillaries, which are closed on one end
2- Lymphatic Capillaries:
Located between cells of many tissues
Merge to form Lymphatic Vessels, which have thin walls and many valves
What is Lymphatic Capillary Components?
1- Lymph inside
2- Endothelium of Lymphatic Capillary
3- Anchoring Filaments:
Anchor the Lymphatic Capillary between tissue cells
4- Openings:
Allow interstitial fluid to drain into Lymphatic Capillary
What is Lymph Trunks and Ducts?
From the Lymphatic Vessels, Lymph passes through Lymph Nodes and then into Lymph Trunks
Lymph Trunks include:
1- Lumbar Trunk
2- Intestinal Trunk
3- Bronchomediastinal Trunk
4- Subclavian Trunk
5- Jugular Trunk
Lymph Trunks then merge to form:
1- Thoracic Duct:
(drains most of the body)
2- Right Lymphatic Duct:
(drains right upper quarter of body)
What is Formation and Flow of Lymph?
1- Interstitial fluid:
Blood plasma filtered from blood capillaries into interstitial spaces to become interstitial fluid
2- Lymph Capillaries:
Absorb interstitial fluid and pass Lymph to Afferent Lymphatic Vessels
Afferent Lymphatic Vessels: (in)
Carry Lymph from Lymphatic Capillaries to Lymph Nodes
Lymph Nodes:
Remove foreign substances through filtering Lymph, Phagocytosis, and Immune Reactions
Efferent Lymphatic Vessels: (out)
Carry Lymph from Lymph Nodes
Valve:
Ensures one-way flow of Lymph
3- Lymph Vessels:
Pass Lymph to Lymphatic Ducts
4- Lymph Trunks
5- Lymph Ducts:
Thoracic Duct or Right Lymphatic Duct
Empty Lymph into the junction of Jugular and Subclavian Veins of the CV System
6- Subclavian Veins
What is Primary Lymphatic Organs and Tissues?
Primary Lymphatic Organs:
Organs where Immune Cells become Immunocompetent
(mature T Cell or B Cell, and checked themselves)
1- Red Bone Marrow
2- Thymus
What is Histology of Thymus?
1- Capsule:
Surrounds Thymus
2- Lobule:
T Cells
Epithelial Cells
Cortex
Medulla
Thymic Corpuscle (Hassall’s Corpuscle)
3- Trabeculae:
Surrounds each Lobule
What is Secondary Lymphatic Organs and Tissus?
Secondary Lymphatic Organs and Tissues:
1- Lymph Nodes
2- Spleen
3- Lymphatic Nodules
What is Structure of a Lymph Node?
1- Afferent Lymphatic Vessels (go in):
Has Valves
2- Subcapsular Sinus
3- Trabecular Sinus
4- Medullary Sinus:
5- Efferent Lymphatic Vessels (go out):
Has Valves
What are the Cells in a Lymph Node?
1- Cells of Medulla:
B Cells
Plasma Cells
Macrophages
2- Cells of Inner Cortex:
T Cells
Dendritic Cells
3- Cells around Germinal Center of Outer Cortex:
B Cells
4- Cells in Germinal Center of Outer Cortex:
B Cells
Follicular Dendritic Cells
Macrophages
What is Structure of Spleen?
1- Visceral Surface:
Splenic Artery
Splenic Vein
Gastric Impression
Colic Impression
Hilum
Renal Impression
2- Internal Structure:
Capsule
Trabeculae
White Pulp (has Central Artery)
Red Pulp (has Venous Sinus and Splenic Cord
What is Lymphatic Nodules?
Lymphatic Nodules:
Masses of Lymphatic Tissue that are not surrounded by a capsule
They are scattered throughout the Lamina Propria of Mucous Membranes lining the GI, Urinary, and Reproductive Tracts and the Respiratory Airways
Mucosa-Associated Lymphatic Tissue (MALT):
Lymphatic Nodules in these areas
What is Innate Immunity?
Innate Immunity:
Wide variety of body responses that serve to protect us against invasion by a wide variety of pathogens and their toxins
We are born with this kind of immunity
2 Lines of defense:
1- Skin and Mucous Membranes
2- Internal Defenses
What is Skin and Mucous Membranes in Immunity?
1- Mechanical Defenses:
Skin
Mucous membranes
Tears
Saliva
Mucus
Cilia
Epiglottis
Urine flow
Defecating
Vomiting
2- Chemical Defenses:
Sebum
Lysozyme
Gastric juice
What is Internal Defenses?
1- Antimicrobial proteins
2- Phagocyte
3- NK Cells
4- Inflammation
5- Fever
What is Phagocytosis Steps?
1- Chemotaxis:
Phagocyte detects chemicals and microbe
2- Adhesion:
Phagocyte sticks to microbe
Uses Pseudopods (feet) to engulf microbe)
3- Ingestion:
Phagosome made from cell membrane around the microbe
4- Digestion:
Lysosome containing Digestive Enzymes fuses with Phagosome
Digested microbe by Phagolysosome
5- Killing:
Microbe killed
Residual Body (vesicle containing indigestible material)
What is Inflammation?
Emigration (Diapedesis) of cells that will help at the site of an injury
Vasodilation opens sinuses for cells to go from vessels to injury site
What is First Line Defense of Innate Defenses by Epidermis?
Function:
Physical barrier to entrance of microbes
What is First Line Defense of Innate Defenses by Mucous Membranes?
Function:
Inhibit entrance of microbes, traps them, not as effective as intact skin
What is First Line Defense of Innate Defenses by Mucus?
Function:
Traps microbes in Respiratory and GI Tracts
What is First Line Defense of Innate Defenses by Hairs?
Function:
Filters out microbes and dust in nose
What is First Line Defense of Innate Defenses by Cilia?
Function:
Together with mucus, trap and remove microbes and dust from Upper Respiratory Tract
What is First Line Defense of Innate Defenses by Lacrimal Apparatus?
Function:
Tears dilute and wash away irritating substances and microbes
What is First Line Defense of Innate Defenses by Saliva?
Function:
Washes microbes from surfaces of teeth and mucous membranes of mouth
What is First Line Defense of Innate Defenses by Urine?
Function:
Washes microbes from Urethra
What is First Line Defense of Innate Defenses by Defecation and Vomiting?
Function:
Expel microbes from body
What is First Line Defense of Innate Defenses by Sebum?
Function:
Forms protective acidic film over skin surface that inhibits growth of microbes
What is First Line Defense of Innate Defenses by Lysozyme?
Function:
Antimicrobial substance in perspiration, tears, saliva, nasal secretions, and tissue fluids
What is First Line Defense of Innate Defenses by Gastric Juice?
Function:
Destroy bacteria and most toxins in stomach
What is First Line Defense of Innate Defenses by Vaginal Secretions?
Function:
Slight acidity discourages bacterial growth
Flush microbes out of Vagina
What is Second Line Defense of Innate Defenses by Interferons (INFs)?
Function:
Protect uninfected host cells from viral infections
What is Second Line Defense of Innate Defenses by Complement System?
Function:
Causes cytolysis of microbes
Promotes phagocytosis
Contributes to inflammation