Lecture 6 Flashcards
What happens at chemical synapses?
Chemicals, or neurotransmitters, are released at the end of neurons
Not all synapses work through
Neurotransmitters
What happens at Gap Junctions?
Neurons are directly connected to their target cells through pores
Electrical Synapses are where
Cells are connected by gap junctions
What happens in Electrical Synapses?
Ions causing an AP move directly from cell to cell through gap junctions
Electrical and chemical synapses differ in which two ways?
- Direction of flow of information
- Speed of transmission
In chemical synapses, AP travels in
One direction
In electrical synapses, AP travels in
Through gap junctions in both directions
Which synapses are faster?
Electrical
Electrical synapses in which
AP moves especially fast
Heart contractions use which synapses?
Electrical synapses
What happens within heart contractions?
Individual muscle cells are connected via gap junctions and electrical synapses, ensuring APs reach the cell at the same time and those cells contract at the same time
Chemical synapses are slower due to
Delays associated with exocytosis, diffusion of neurotransmitters, and binding to receptors on the target cell
With chemical synapses, you can
Vary the type of chemical released, able to generate more diverse signals
Cells use microtubules to
Transport substances to different regions of the cell
Microtubules are composed of
Long strings of Tubulin
What is Tubulin made of?
Alpha tubulin and beta tubulin
What causes the charge difference important for assembly and growth of microtubule?
Alpha and beta tubulin combine, resulting in alpha-tubulin having negative charge
Positive and negative ends of tubulin attach to form a
Growing chain or protofilament
Protofilaments line up to form a
Sheet that eventually rolls into a long tube to form a microtubule
Cells arrange their microtubules like
Spokes on a wheel
Microtubules extend out towards the edges of the cell from a
Central microtubule organizing center
Which ends of the microtubule remain at the center?
Negative end stays at the center and is attached to the organizing center
Which end of the microtubule is closest to the cell membrane?
Positive end
How does color change occur in camouflaged animals?
Pigment granules are transported from the microtubule organizing center to the outside of the skin via microtubules in frogs
Motor proteins recognize the charge difference of tubulin and uses it to
Move in a specific direction
What are motor proteins?
Proteins that move along microtubules and carry cargo
What are the types of motor proteins?
- Kinesin
- Dynein
Kinesin carries cargo to the
Positive end (to the right)
Dynein carries cargo to the
Negative end (to the left)
What does Kinesin carry?
Neurotransmitter-filled vesicles are carried from the soma down the axon on microtubules
What does Dynein carry?
Empty-vesicles from the synapse back to the soma
Vesicles and neurotransmitters are not made in the synapse, but in the
Soma
What are needed for muscle contraction?
Microfilaments
Microfilaments are composed of
Long strips of Actin that associate with the motor protein Myosin
Microfilaments assemble similarly to
Microtubules
The association of myosin with actin is associated with
The basis of muscle contraction
Myosin forms thick filaments, which lie between
Actin’s thin filaments
The arrangement of myosin between actin is critical for muscles to
Generate the most force from contraction and cause striations
