Spock/Physiology

Although half Human, Spock's physiology retained most of its Vulcan characteristics such as the green blood, the placement of his liver, () his strength, () telepathic abilities, () and his greater lifespan (; ; ; ) when compared to the average Human. However, it should also be noted that the life he lived was still about forty years shorter than the average Vulcan, who generally lived to be around two hundred years old. His father Sarek, for example, was 203 at his death. (; ; ; )
His Human characteristics were obvious when Sarek was in need of a blood transfusion and concern over donating his hybridized blood would be a danger to Sarek's full Vulcan physiology. () The other instance where his Human side was evident happened during the final stages of his Kolinahr ritual acceptance. While on Vulcan performing the ritual, the V'ger probe approached proximity and its own emotional instability affected Spock's Human emotional side which he worked so hard to repress. () Spock's Human side was also present when spores affected him on Omicron Ceti III. () 
Like most Vulcans, he experienced pon farr neurochemical imbalance at least every seven years until the symptoms were remedied through ritual mating or kal-if-fee (dueling). If not dealt with, a Vulcan could die within eight days of the first symptoms. Spock experienced pon farr at least twice, once performing the kal-if-fee with Kirk's assistance, once mating with Saavik while physiologically a youth as a result of his regeneration by the Genesis Device. Both successfully relieved his symptoms of pon farrs neurochemical issues. (; )
As of Vulcan rituals concerning death, Spock was able to transfer his katra into someone that was close to him – such as a family member – who could then transfer the katra into a large repository on Vulcan. In his case, he picked Dr. McCoy as a host for his katra when he decided to expose himself to fatal warp core radiation in order to restore warp power to the Enterprise. His corpse regenerated when his torpedo casing casket was shot towards the Genesis planet and was subjected to the Genesis cycles that rapidly evolved all life on the planet. (; )
After Spock received a mind meld from Captain Picard, he seemed to have accepted his Human side. He admitted to being emotionally compromised and showed some emotions when he dealt with Nero destroying Vulcan in the alternate timeline and dealing with his younger self. (; )
On his Human side, Spock once implied he had an ancestral relationship to British author Sir Arthur Conan Doyle. ()