Lecture 1 Flashcards
immune system
network of organs, tissues, cells, and molecules designed to identify and protect the body from infectious disease
organs and tissues are connected by both _____ and ______
blood and lymphatic vessels
Two groups of the immune system
- primary 2. secondary
primary
central or regenerative, developing cells, contain developing lymphocytes, bone marrow and thymus
secondary
peripheral, contain more mature cells, spleen, lymph nodes, MALT (mucosal associated lymphoid tissue)
bone marrow
-site of hematopoiesis (the development of all blood cells from progenitor stem cells) - site of B cell maturation - as persons age, most hematopoiesis in flat bones
thymus
-bi-lobed organ in upper anterior thorax - each lobe surrounded by capsule, divided into multiple lobules - rich vascular - undergoes physiologic involution with aging - major site of maturation and selection of T-cells
sail sign
radiograph of thymus on chest in infant
spleen
large, vascular organ in left upper quadrant of the abdomen . under the diaphragm - has two sections (white and red pulp) - major site of immune responses to pathogens and other foreign substances in the blood
white pulp
contains lymphocytes (T-cells near arterioles in the periarteriolar sheath; B cells are more peripheral
red pulp
involved with red blood cell breakdown
lymph nodes
- small nodular aggregates of lymphoid tissue (500-600 in human body) - located along lymphatic channels vessels - often the first organized lymphoid structure to encounter foreign antigens
lymph node structure
- outer fibrous capsules - multiple afferent (going in ) lymphatic vessels and one efferent (going out) lymphatic vessel - three concentric regions (the cortex, paracortex, and medulla
cortex of lymph node contains
cell aggregates called follicles which may contain germinal centers
fluid draining from the lymph node is enriched with
antibodies and lymphocytes
cervical lymph nodes
location: head and neck site of drainage- scalp, face, nasal cavity, and pharynx
axillary lymph nodes
location: axilla site of drainage- arm, chest wall, and breast
inguinal lymph nodes
location- groin site of drainage- genitalia, buttock, anus, abdominal wall, leg
mediastinal lymph nodes
location- in/near mediastinum, central posterior thorax site of drainage- mid-chest, upper abdomen, lungs
mesenteric lymph nodes
location- lower abdomen, near intestine site of drainage- small and large intestine upper rectum
MALT
mucosal associated lymphoid tissue, aggregates of lymphocytes found throughout mucosal surfaces in body; rich in antibodies
peyers patch
small masses of lymphatic tissue
lymphatic system
white blood cells and plasma (no erythrocytes and not circular system like vascular system) - transports immune cells to and through the nodes and back into circulation - collects/drains excess fluid from the surrounding tissues to return it to the vascular system - absorbs fat from the villi of the small intestine
Flow of lymphatic fluid is conducted by
- skeletal muscle contraction 2. smooth muscle contractions 3. unidirectional valves 4. arterial pulsation NO “PUMP” (like in the heart for the vascular system)
T/F lymph fluid flows through multiple lymph nodes before draining back into blood circulation
true
lymphatic drainage is initiated by
interstitial fluid uptake
lymph from the upper right side of the body drains to the _________ which empties into the _________
right lymphatic duct; right subclavian vein
lymph from the rest of the body drains to the _______ which empties into the _________
thoracic duct; left subclavian vein
T/F contents of lymph fluid changes as progresses closer to circulation
true increased immune cells and antibodies as it exits through efferent vessel
lymphedema
interstitial collection of lymph due to disruption of lymphatic flow - usually progressive and can lead to hypertrophy or fibrosis - swelling, skin changes, pain, restricted range of motion, and non-pitting edema
complications of lymphedema
skin infections, malignancy, reduced quality of life including aspects of emotional physical and social well being
Two types of lymphedema
primary and secondary
primary lymphedema
due to genetic disorder can present at any age
secondary lymphedema
due to underlying disease or is a consequence of prior treatment - in US due to malignancy or cancer therapy (most common in breast cancer patients)
filariasis
most common cause of secondary lymphedema worldwide - due to infection by nematode - transmitted via mosquitoes (worms reside in lymphatic vessels and nodes in legs and in scrotum)
diagnosis of filariasis
blood smear (blood draw at night when the organisms are in the peripheral blood)
treatment of filariasis
diethylcarbamazine (DEC)
lymphagitis
inflammation fo lymph vessels most common pathogen is streptococcus pyogenes
chylothorax
term used for accumulation of lymph in the thorax - often caused by accidentally severing the thoracic duct during surgery
lymphadenopathy
enlargement (less than 1 cm) of one or more lymph nodes
lymphadenitis
lymphadenopathy with pain and or signs of inflammation
lymphoma
type of cancer / malignancy of varied cells of the immune system
two components of adaptive immunity
cell mediated immunity and antibody mediated (humoral) immunity
innate response cells
monocytes, macrophages, basophils, eosinophils, neutrophils, natural killer cells, and mast cells
neutrophil is what type of cell and have what function
WBC granulocyte; engulf bacteria and fungi, oxidative burst
monocyte/macrophages are what types of cells and has what function
WBC mononuclear; engulf bacteria, fungi, and cellular debris, produce cytokines, antigen producing
eosinophils are what types of cells and have what function
WBX granulocyte, associated with allergic reaction and parasitic infection
basophils are what types of cells and have what function
WBC granulocytes, associated with hypersensitivity and release of histamines
mast cells
derived from bone marrow cells; granules contain vasoactive amines like histamine, proteases kill bacteria
natural killer cells
WBC lymphocytes; recognize stressed or infected cells and kills them by secreting macrophage activating cytokine INF gamma
B-cell
WBC lymphocyte; specific recognition of antigens as mediator of humoral immunity
T-cells
WBC lymphocyte; specific recognition of antigens as mediator of cell mediated immunity
plasma cell
eosinophil
monocyte
lymphocyte
basophil
neutophil
mast cell
neutrophil
eosinophil
mast cell
dendritic
bone marrow dervived; pharocytic, antigen presenting and initiatio of t-cell responses
follicular dendritic
mesenchymal dervied; antigen presenting, display antigens to B-cells in humoral immune responses
cytokines
group of proteins produced and secreted by the immune and nonimmune cells to act as intercellular mediators to alter biological resposnes; can be endocrine, paracrine, or autocrine
autocrine
same receptors that secretes it
ex. IL-2
paracrine
acts on an adjacent or nearby cell
endocrine
acts at a distance to stimulate cells
what signaling pathway do cytokines typically activate
JAK-STAT signaling pathway
innate immmunity cytokines
proinflammatory cytokines
TNF alpha, IL 1 and IL 6
adaptive immunity cytokines
chemokines
unique type of cytokine; causes cells to migrate towards a concentration gradient of the chemokine
two major groups are CC and CXC
coagulation system
additional molecule of the immune system; cascade of plasma enzymes which with platelets help to form clots
lomom system
second enzyme cascade tiggered by tissue damage
protease inhibitors
enzymes that cleave proteins and breakdown inhibitors
defensins
antimicrobial peptides produced by a variety of cell types that can penetrate microbial membranes and destroy bacteria, fungi, and enveloped viruses
