PCS 1 Flashcards
What are the different types of cell-cell junctions
tight junctions gap junctions adherans junctions desmosomes hemidesmosomes
Where do you find tight junctions
bladder, skin as they must be waterproof
Where do you find gap junctions
smooth muscle, cardio, must have room to contract
What special function do gap junctions have which makes it useful to cardiac cells
allows chemical communication between adjacent cells
What are the key properties and functions of type 1 collagen fibres
adds strength by twisting chains of collagen, forms scar tissue, forms fibrous proteins
What are the key properties and functions of elastin fibres
Snap back to original length when relaxed. Provides elasticity and resilience to tissues
What are the key properties and functions of hyaluronan
Expands rapidly in water and can be used to treat joint conditions. It forms a part of synovial fluid
What are the key properties and functions of aggrecan
Component of cartilage, constantly trying to expand and draw water in.
Describe the epithelium of the skin
Stratified squamous epithelial cells. Thick (5) layers on hands and feet, thin (4) layers everywhere else. Certain layers more able to mutate than others
Why is it important for most cells to be pressed closely together
Keeps them impermeable
Reduces stress on cells
Junction diversity can be used to causes ranging permeability
Tightly packed cells offer greater protection
What are the main components of extracellular matrix
Glycosaminoglycans
Hyaluronic acid
Collagen
Elastin
What are the layers of skeletal muscle
Epimysium - outer layer, allows contraction
Perimysium - layers separating section allows nervous input
Endomysium - Contains extracellular fluid tissue
Describe the connective tissue around nerves
Endoneurium - surrounds axon
perineurium - surrounds nerve bundles
epineurium - encloses nerve and blood vessels
What parts of the cytoskeleton are involved in muscle contraction and which one generates force
Actin and myosin - myosin generates force
How are vesicles moved around cells
motor proteins - kinesin and dynein
How are ribosomes ‘attached’ to the RER
When a protein is formed signal sequences high in leucine triggers binding of signal recognition particle which binds to the ribosome, receptor and translocon, giving the appearance theyre all connected
What do the cis and trans end of the Golgi body do
Cis - incoming
Trans - outgoing
Inside nerve cells, are the concentrations of K, Na and Cl high or low
K - high
Na - low
Cl - low
Outside nerve cells, are the concentrations of K, Na and Cl high or low
K - low
Na - high
Cl - high
What is a resting potential
A voltage difference across the cell membrane when the cell is at rest
What maintains the unequal distribution of ions across the nerve cell membrane
Sodium/potassium pump, powered by Sodium/Potassium ATPase
Which ion type is the nerve cell membrane more permeable to
K+
How do action potentials propagate down unmyelinated axons
Local currents
Membrane has absolute refractory to ensure unidirectional propagation
How do action potentials propagate down myelinated axons
Impulse jumps over myelin for faster conduction
