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A Handbook of Biology
ÇÅRDÏÅÇ MÜSÇLË
Contractile tissue
Involuntary muscle seen only in the heart.
Cell junctions fuse the plasma membranes of
cardiac muscle cells and make them stick
together.
Communication junctions (intercalated discs)
at some fusion points allow cells to contract as
a unit, i.e., when one cell receives a signal to
contract, other cells also contract.
3
ÑËÜRÅL TÏSSÜË
Made up of neurons (unit of
neural system).
Responsible for control and co-
ordination of the body.
Neurons are excitable cells.
They carry impulses.
Neurons are protected and
supported by neuroglial cells.
(AIPMT 2009)
Neuroglia make up more than half the volume of neural tissue.
ØRGÅÑ ÅÑD ØRGÅÑ SÝSTËM
Cells ¾® Tissues ¾® Organs ¾® Organ systems.
This organization is essential for better coordinated activities of cells.
An organ is made of one or more type of tissues. E.g. Heart has epithelial,
connective, muscular & neural tissues.
MØRPHØLØGÝ & ÅÑÅTØMÝ ØF ÇØÇKRØÅÇH
Morphology: Study of external features of organisms.
Anatomy: Study of internal organs of organisms.
Cockroach (Periplaneta americana) are nocturnal, omnivores that live
in damp places.
Neuroglia cell
Neuroglia
cell