Anatomy Flashcards
What is the function of an Erythrocyte?
Carries O2 & CO2 to lungs
What does an Erythrocyte look like?
Anucleate & biconcave, w/ large SA to volume ratio for rapid gas exchange
What is the life span of an Erythrocyte?
120 days
What is the energy source for an erythrocyte?
Glucose (90% used in glycolysis, 10% used in HMP shunt)
What does an Erythrocyte membrane contain?
Chloride HCO3- & transport CO2 from the periphery to the lungs for elimination
What is Erythrocytosis?
Polycythemia= Inc hematocrit
What is Anisocytosis?
Varying size
What is Poikilocytosis?
Varying shapes
What is an Reticulocyte?
Immature erthrocyte, marker of erythroid proliferation
What are Platelets (thrombocytes) involved in?
1° hemostasis
What are Platelets derived from?
Small cytoplasmic fragment derived from megakaryocytes
What is the life span of a Platelet?
8-10 days
What happens when platelets are activated by endothelial injury?
Aggregates w/ other platelets & interacts w/ fibrin to form platelet plug
What do Platelets contain?
Dense granules (ADP, Ca) & alpha granules (vWF, fibrinogen)
Where is approximately 1/3 of the platelet pool stored?
Spleen
Thrombocytopenia or platelet dysfunction results in ____.
Petechiae
What is the vWF receptor for platelets?
GpIb
What is the Fibrinogen receptor for platelets?
GpIIb/IIIa
What are Leukocytes divided into?
Granulocytes (neutrophil, eosinophil, basophil) & mononuclear cells (monocytes, lymphocytes)
What are Leukocytes responsible for?
Defense against infections
What is the normal level of Leukocytes?
4,000-10,000 cells/mm3
What is the WBC differential from highest to lowest?
- Neutrophils (54-62%)
- Lymphocytes (25-33%)
- Monocytes (3-7%)
- Eosinophils (1-3%)
- Basophils (0.0.75%)
What is the acute inflammatory response cell?
Neutrophil
When do Neutrophils increase?
Bacterial infections
What is the histo of a neutrophil?
Multilobed nucleus
What do the small more numerous, specific granules in neutrophils contain?
- Alkaline phosphatase
- Collagenase
- Lysozyme
- Lactoferrin
What do the Larger, less numerous azurophilic granules (lysosomes) contain?
- Acid phosphatase
- Perioxidase
- ß-glucuronidase
What is seen in Vitamin B12/folate deficiency?
Hypersegmented polys (5 or more lobes)
What does an inc in Band cells indicate?
Immature neutrophils reflext states of inc myeloid proliferation (bacterial infections, CML)
What do Monocytes differentiate into?
Macrophages in tissues
What is the histo of a Monocyte?
Large, kidney-shaped nucleus
Extensive “frosted glass” cytoplasm
What are the functions of Macrophages?
Phagocytoses bacteria, cell debris & senescent RBCs & scavenges damaged cells & tissues
What is the life span of Macrophages?
Long life in tissues
What do macrophages differentiate from?
Circulating blood monocytes
What activates Macrophags?
Gamma-interferon
What can macrophages function as?
Ag-presenting cell via MHC II
What is the cell surface marker for macrophages?
CD14
What are the functions of Eosinphils?
- Defends against helminthic infections (major basic protein)
- Highly phagocytic for Ag-Ab complexes
What is the histo of an Eosinophil?
Bilobate nucleus
What are eosinophils packed with?
Large eosinophilic granules of uniform size
What do eosinophils produce?
Histamine & arylsulfatase (helps limit reaction following mast cell degranulation)
What causes eosinophilia?
- Neoplastic
- Asthma
- Allergic processes
- Collagen vascular dz
- Parasites (invasive)
What do Bsophils do?
Mediate allergic reaction
What do Basophils contain?
Densely basophilic granules containing heparin (anticolagulant), histamine (vasodilator) & leukotrienes (LTD4)
What is the function of a Mast cell?
Mediates allergic reaction in local tissues
Mast cells resemble ___ structurally & functionally but are not the same cell type.
Basophils
What can mast cells bind to?
Fc portion of IgE to membrane
What happens when IgE cross-links upon Ag binding?
Causes degranulation which releases histamine, heparin & eosinophil chemotactic factors
Mast cells are involved in ___ hypersensitivity reactions.
Type I
What does Cromolyn sodium prevent?
Mast cell degranulation (used for asthma prophylaxis)
What are Dendritic cells?
Highly phagocytic Ag-presenting cells (APCs)
What do Dendritic cells function as?
A link b/w innate & adaptive immune system
What do Dendritic cells express?
MHC class II & Fc receptor on surface
What are Dendritic cells called in the skin?
Langerhans cells
What is the function of a Lymphocyte?
Mediates adaptive immunity
What are lymphocytes divided into?
B cells & T cells
What is the histo of a lymphocyte?
Round, densely staining nucleus w/ small amount of pale cytoplasm
What are B lymphocytes apart of?
Humoral immune response
Where do B lymphocytes arise from?
Stem cells in bone marrow
Where do B lymphocytes mature?
Bone marrow
Where do B lymphocytes migrate to?
Peripheral lymphoid tissue (follicles of LN, white pulp of spleen, unencapsulated lymphoid tissue)
What happens when Ag is encountered?
B cells differentiate into plasma cells that produce Ab & memory cells
B lymphocytes can function as ___ via ___.
APC via MHC II
What do Plasma cells produce?
Large amounts of Ab specific to a particular Ag
What is the histo of a Plasma cell?
Off-center nucleus, clock-face chromatin distribution, abundant RER & well-developed Golgi apparatus
What is Multiple Myeloma?
Plasma cell cancer
What is the function of a T lymphocyte?
Mediates cellular immune response
Where do T lymphocytes originate from?
Stem cells in bone marrow
Where do T lymphocytes mature?
Thymus
What do T cells differentiate into?
- Cytotoxic T cells (express CD8, recognize MHC II)
- Helper T cells (express CD4, recognize MHC II)
- Regulatory T cells
What is the costimulatory signal for T cell activation?
CD28
What are the majority (80%) of circulating lymphocytes?
T cells