Who is Tristram's Mother from The Life and Opinions of Tristram Shandy and what is their importance?

Tristram's mother is a source of frustration for his father and perhaps for this reason, Tristram does not look upon her favorably. At the beginning, she interrupts her husband's lovemaking with a question about the cuckoo clock and then exacerbates him further by insisting on having the mid-wife deliver her baby rather than her Husband's choice of Dr. Slop. Tristram suggests that his father and mother were not the perfect match as she constantly frustrates her husband by showing no interest in either arguing or providing stimulating conversation.