Sore Throat Flashcards
(47 cards)
Structure and Functions of cell membrane
- Regulates movement of molecules in and out of the cell
— the membrane is hydrophobic but contains proteins that allow movement of hydrophilic molecules - cell-cell interactions and cell signalling/recognition
— contains glycoproteins
Structure and function of micro filaments
- double strands of actin about 7nm thick
- forms a mesh below the plasma membrane
- it’s components are linked to proteins in the cell membrane
— these in turn may connect with the molecules in the ECM
—- this helps the cell to fix its shape with respect to the external environment and if necessary, move around
What are actin filaments - structure and function
- provide support for the cell membranes
- form a core of membrane projections such as microvilli
- microvilli are present in cells that need to absorb substances form them Extracellular medium such as kidneys and intestine
Structure and function of microtubules
- participate in the intercellular movement of organelles
- made up of 2 globular proteins; alpha and beta tubulin polymerised into protofilament
- 13 protofilaments are arranged to form a tube called a singlet —> which can be enlarged to form a doublet or a triplet
Where are centrosomes made and found
They are made from microtubules and found near the nucleus
What is fast axonal transport?
In the neurones, the proteins required by the synapse are manufactured in the cell body and transported along the microtubules
Fast axonal transport happens in how many directions?
Both:
- anterograde transport carries new material from the cell body to the synapse and is carried out by kinesins
- retrograde transport carries materials back to the cell body for destruction in the lysosomes and is carried out by the motor proteins, dyneins
Structure and function of Golgi
Segment names close to nucleus - away: cis, median, trans.
- modification of proteins and lipids, primarily by glycosylation
- sorting and distributing to other organelles within the cell or packaging to be secreted from the cell
- vesicles move from trans Golgi to the membrane via cytoskeletal filaments
Types of junctions:
- tight junctions: prevent movement of substances between cells
- adhering junctions: which maintain cellular positions
- gap junctions: which allow movement of substances between cells
Distribution of total body water percentage
Intracellular fluid: 40% of body weight
Extracellular fluid: 20% of body weight
- interstitial fluid: 15% of TBW
- blood plasma: 5% of TBW
What are the three components needed for homeostasis?
Sensor, control centre and effector
Types of control systems and examples
OPEN LOOP
- no feedback could result in run-away reactions: controller –> controlled component –> output
CLOSED LOOP
- output of the system feeds back and influences the controller: controller –> controlled component –> output –> sensor –> feedback –> controller
- negative feedback: return to set point.
- positive feedback: moves away from set point
FEEDFORWARD:
- response generated in anticipation of a change: Precision of control depends on power and speed of response of controller
and sensitivity of the sensor
Where is the central control of thermoregulation?
Integration of signals from 2 types of thermoreceptors:
- cutaneous: convey info via anterolateral pathway
- internal warm: located in preoptic nucleus of the hypothalamus and cervical spinal cord which monitor core temp.
Both these sources send input to the posterior hypothalamus which acts as a thermostat.
What is the body’s response to infection?
Increase temperature set point:
- bacteria/waste products phagocytosed by leukocytes (WBC)
- pyrogens (cytokines) released
- binds at hypothalamus
- change in set point
Function of lysosome
Act by damaging bacterial cell walls, but so no harm to eukaryotic cells as they do not have a cell wall
Functions of mannose binding proteins and c-reactive proteins
Mannose binding proteins: act through recognition of particular carbohydrate patterns found on the surface of many pathogenic microorganisms
C-reactive proteins: bind to phosphorylcholine on bacteria, enhancing phagocytosis and assist in complement binding
What do virally infected cells release?
Interferons
What are are the important cytokines secreted by macrophages and their function?
IL-1
- activates: vascular endothelium and lymphocytes
- tissue destruction
- fever
IL-8
- chemo-taxis
- activation of PMN’s
TNF-a
- increase vascular permeability inc drainage to LN’s/blocks back flow to blood stream
- fever
IL-6
- activates lymphocytes
- acute phase
- proteins
- fever
IL-12
- activates NK’s
- CD4+ to Th1 response
Basophils and mast cells function
Basophils in blood and mast cells in tissues are both mobile and chemotactic but not phagocytic.
- they are activated directly by chemical and physical stimuli.
- they are also activated by nerves, complement and receptors —> allowing them to interact with the adaptive immune system
Phagocytes: examples and features of the main two
Phagocytes such as neutrophils, monocytes/macrophages, dendritic cells and eosinophils deploy a variety of cell surface receptors which can detect non self and damaged tissues
Two main types: neutrophils v macrophages
- Abundant; less numerous
- migrate to tissues during infection; reside in tissues
- short lived; long lived
- express MHC class I; express MHC class I
- pattern recognition; pattern recognition through toll-like receptors
- responsible for pus formation; up-regulate MHC class II - a link to adaptive immunity
Major functions of proteins, carbohydrates, nucleic acid and lipids
Proteins: structure and catalyst
Carbohydrates: energy source and marker
Nucleic acid: generic information
Lipids: energy store and cell membrane
Bacillus anthracis
Gram positive bacteria Causative agent of anthrax Infects wild and domestic animals Produces spores that last in soil for long time Category 3 pathogen: • Humans are rarely infected • Multiple form of the disease • High mortality in some forms of the disease
How people are infected with anthrax
- Working with infected animals or animal products: inhalation and cutaneous anthrax
- People who eat raw or undercooked meat from infected animal: Gastro Intestinal anthrax
- Injecting heroin: injection anthrax
Pathogenesis of anthrax
CAPSULE: polypeptide capsule consisting of poly-D- glutamic acid is produced:
• Synthesis of the capsule is by three enzymes encoded by capA, capB and capC on plasmid pX-02
• A forth enzyme encoded by the dep gene, catalyses the formation of polyglutamates that inhibit phagocytosis
TOXIN: two binary toxins, edema factor (EF) and lethal factor (LF) bind a third toxin component, protective antigen (PA).
• The three toxin components are encoded on plasmid pX-01
