( Essentially ( , ( these ( ( are ( ( tubelike pockets ) ( of ( ( the epidermis ) ( that ( ( ( extend ( through ( ( most or ) ( all ( of ( ( the depth ) ( of ( the skin ) ) ) ) ) ) ) ) and ) ( enclose ( ( a ( small papilla ) ) ( of ( dermis ( in ( their base ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Essentially)) (, ,) (NP (DT these)) (VP (VBP are) (NP (NP (JJ tubelike) (NNS pockets)) (PP (IN of) (NP (NP (DT the) (NNS epidermis)) (SBAR (WHNP (WDT that)) (S (VP (VP (VB extend) (PP (IN through) (NP (NP (JJS most)) (CC or) (NP (NP (DT all)) (PP (IN of) (NP (NP (DT the) (NN depth)) (PP (IN of) (NP (DT the) (NN skin))))))))) (CC and) (VP (VB enclose) (NP (NP (DT a) (JJ small) (NN papilla)) (PP (IN of) (NP (NP (NNS dermis)) (PP (IN in) (NP (PRP$ their) (NN base)))))))))))))) (. .)))
Essentially, these are tubelike pockets of the epidermis that extend through most or all of the depth of the skin and enclose a small papilla of dermis in their base.
(ROOT (S (NP (JJS Most) (NN skin) (NNS structures)) (VP (VB originate) (PP (IN in) (NP (DT the) (NNS dermis)))) (. .)))