Immune System - Lymphatic And Immune Flashcards
What is immunity?
- Ability to resist damage from pathogens, toxins and internal threats
What makes up the immune system?
- Lymphoid tissues / Lymphatic System
- Immune cells
- Chemicals that coordinate and carry out immune functions
- “self ” from “non-self” - a targeted response
What are the functions of the immune system?
- Recognize and remove abnormal “self ” cells
- Removes dead or damaged cells
- Protects the body from disease-causing invaders
What are the types of responses of the immune system?
- Nonspecific Innate Immunity and Specific Acquired Immunity
What is the lymphatic system?
- System of vessels / cells / organs that carries excess fluids to the bloodstream and
filters pathogens from the blood - drain body fluids and return them to the bloodstream
What is the lymph?
Lymph: interstitial fluid (fluid that fills spaces between cells) once it has entered
the lymphatic system
What is the function of the lymphatic system?
- Fluid Balance
- Lipid Absorption
- Defence against pathogens
What makes up the lymphatic system?
Tonsils, the lymph nodes, the spleen, the thymus
What are lymph nodes + where are they located?
Lymph nodes -located along lymphatic vessels
* Groups in the cervical (neck), axillary (armpit), and inguinal
(groin) areas
Describe the way lymph is able to carry fluid from tissues to the circulatory system
- Vessels begin as open-ended capillaries,
- Feed into larger lymphatic vessels
- Empty into the bloodstream by ducts.
- Lymph travels through the lymph nodes
- Doesn’t circulate ie not pumped by heart
- Forced through the vessels by contraction of skeletal muscles
What are the function of the capillaries in the lymphatic system? + characteristics
- Where fluid enters the lymphatic
system - In virtually all tissues
- between arterioles and venules
- Thinner walls than veins
*fluid moves into the capillaries only (in one direction)
What does the lymphatic system entail in the small intestine?
*found in vili of GI tract
*lymphatic capillaries called lacteals
*lipids and some lipid soluble vitamins form a milky fluid = chyle
*this fluid enters the lacteals and blood stream
Outline lymphatic circulation
- Lymphatic capillaries → Vessels → Trunks →2 ducts
Describe drainage in the right duct and left duct
- Right: Right lymphatic duct drains into right subclavian vein
- right sides of the head, thorax,
and right arm - Left: Thoracic duct drains
into the left subclavian vein - remaining portions of the body
What is lymphatic tissue?
*lymphocytes/ defence cells
Where are lymphocytes found?
red bone marrow
What type of tonsils are lymphatic?
- Palatine tonsils
- Pharyngeal tonsils (adenoids when enlarged)
- Lingual tonsil
Where are lymph nodes located + how they involve in lymph travel?
- Distributed along the lymphatic vessels
- Lymph passes through before entering
blood - Superficial or deep
*lymph flows through the nodes
Describe how lymph nodes get rid of pathogens
- Superficial aggregations
- (1) inguinal nodes in the groin, (2) the axillary
nodes in the axilla (armpit), and (3) the cervical
nodes in the neck. - Dense capsule with extensions: trabeculae
- lymphatic tissue: Lymphocytes and lymphatic
nodules - lymphatic sinuses: macrophages
macrophages remove pathogens
What does the spleen do?
*filters blood
= responds to foreign substances, destroy old RBC
What is found In the spleens?
*white pulp
*red pulp
What is white pulp + what is its role?
- Lymphatic tissue surrounding arteries
- Lymphocytes can be stimulated to divide
What is red pulp + what is its role?
- Surrounding veins
- Macrophages and red blood cells
- Macrophages remove foreign substances
and worn-out red blood cells through
phagocytosis
*also a blood reserviour
What is the thymus and what is it composed of?
- 2 lobed gland
- Divided into lobules
- Cortex (dark)
- Many lymphocytes
- Medulla (light)
- Fewer lymphocytes
- Maturing T-cells
- Mature T-cells migrate to medulla, enter blood and travel to other lymphatic tissue
What cells of the immune system circulate the blood but leave and act extra vascular?
(1) eosinophils
(2) Basophils (blood); related mast cells (tissues)
(3) neutrophils
(4) monocytes and macrophages
(5) lymphocytes and plasma cells
(6) dendritic cells
What cell is found in the immune system?
leukocytes = WBC
What do basophil and mast cells do?
- Release mediators that contribute to inflammation
- Histamine, heparin (anticoag) and other cytokines
- Allergic and immune responce
Where are basophils and mast cells found?
- Basophils (circulation)
- Mast cells (tissue):
- lungs
- GI tract
- skin
What are eosinophils and what do they do?
- Allergic reactions and parasitic diseases
- Cytotoxic: release substances from their granules that directly
damage or kill the parasites
Where are eosinophils found?
- Digestive tract, lungs, urinary and genital epithelia, and
connective tissue of the skin
What do neutrophils do?
- Kill / ingest bacteria
- release a variety of cytokines
- including fever-causing pyrogens
*phagocytic cells
*most abundant WBC
*has a segmented nucleus
Where are neutrophils located?
- Most remain in the blood but can leave if attracted to an
extravascular site of damage or infection
What do monocytes and macrocytes do?
Monocytes precursors of tissue macrophages
* Once in the tissues, monocytes enlarge and differentiate into
phagocytic macrophages
* Key scavengers within tissues
* Antigen Presenting Cell (APC)
* Antigens: Immunogens that react with B and T lymphocytes
* APCs can insert fragments of processed antigen into its membrane -
becomes part of surface protein complexes
* they can bind to and activate other types of immune cells.
Where are monocytes and microcytes located?
*in tissues
What are the types of lymphocytes?
- B Lymphocytes (APCs)
- T lymphocytes
*natural killer cells
Where are lymphocyte cells found?
lymphoid tissue
What do dendritic cells do?
- Once capture antigens migrate to lymph nodes
- Present antigens to lymphocytes which activates
lymphocytes
*antigen presenting cells
Where are dendritic cells found?
- Found in skin (Langerhans cells)
What happens in antigen presentation?
- Some pathogens bind directly
to phagocyte receptors /others pre-coated by
antibodies - Stimulates internalisation
- Digests pathogen
- Part of it (antigen) presented on
surface
