Lecture 9 Flashcards
Are there more contractile or electrical cells in the heart
Contractile
Structure of electrical cells?
pale, strained apparence with low actin and myosin because they only weakly contract
What is the role of electrical cells?
To conduct an electrical signal quickly signalling the the contractile cell that it’s time to contract
What type of signal is sent by electrical cells
electrical - calcium signal
Why do electrical cells have less actin and myosin?
Only Weakly contract and allows more room for ions to flow through and communicate
Structure of contractile cells/
strained appearance with high actin and myosin.
Do APs propagate along the surface membrane of both cells?
Yes
What is the Sinoatrial Node (SA) node?
A collection of Cells.
Pacemaker that tells the heart when to beat.
Where depolarisation starts.
It is in communication with conduction cells
Where does electrical signal travel?
Down to contractile cells and between neighbouring electrical cells
What occurs in contractile cells?
Increased cytotoxic Calcium levels, cross bridge attachment and contraction
What structure connects most cells of the heart?
Intercalated discs (which contain gap junctions)
What are the pores on intercalated discs and what is their purpose?
Gap junctions - allow different types of molecules to move from one cell to the next.
Features of Gap junctions?
Small to limit the amount moving through.
ions move easily through gap junctions, increasing ca concentration
Where are gap junction located?
Between electrical and contractile cells, and between other contractile cells.
Function of gap junctions?
To increase speed of impulse throughout the heart
