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Functional cell. Ajith Sominanda Department of Anatomy Faculty of Medicine University of Peradeniya. Multi cellular organism and the cell. CELL is the basic structural functional unit of life However, in multicellular organism, cells with specific function aggregate to form a tissue.
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Functional cell Ajith Sominanda Department of Anatomy Faculty of Medicine University of Peradeniya
Multi cellular organism and the cell CELL is the basic structural functional unit of life However, in multicellular organism, cells with specific function aggregate to form a tissue. Therefore the functional unit of multi cellular organism is TISSUE
Aim of this lecture Function Structural adaptation/s of the cell These cells are called parenchymal cells in the tissue or the organ
Functions of the cell General functions Multiplication and growth Metabolism Cellular homeostasis Respond to the environmental stimuli Specific functions epithelial cell Connective tissue cell Muscle cell Nerve cell
Multiplication and growth of the cell • Depend on the stimulation (signal), cell starts to multiply and grow • These stimulations can be normal physiological or pathological
Pathological Multiplication and growth of the cell ‘Neoplasms’ ‘Tumors’ ‘’Cancers’’
Metabolism Endoplasmic reticulum (ER), Golgi apparatus & vescicles - The factory of life the scavengers or recycling system Endo-lysosomal system
Specific cellular functions • Cell structures change from its basic form (differentiate) to a specialized form to perform specific functions • Covering and lining • Secretion • Absorption • Support • Contractility and movement • Communication and response to stimuli
Covering and lining by epithelial cell • Shape and form of the cell contributes to the function
Covering and lining by epithelial cell • Cellular adhesions and basement membrane is critical for the integrity of the epithelium
Covering and lining by epithelial cell • Presence of several cell layers to enhance the covering or lining function
Secretory cells • (Protein) synthetic machinery is fully functional • Nucleus is active • ER is active Glands (exocrine) Glands (endocrine)
Cells with absorptive function • Intestinal epithelial cells are adapted to increase the surface area
Cells adapted to supportive function • Fibroblasts secretes fibers and maintain the cellular matrix
Contractility and movements • Cilia are cell surface specializations that moves the substances on the cell surface
Contractility and movements • Muscle fibers are arranged in longitudinal orientation • Fibers are arranged in bundles • Contractile elements are central and nuclei are peripheral
Communication and response • Environment information transfer Information processing response Receiver Processor Effector
Communication and response • Neuron has short and long processes • Long processes are often covered with myelin to insulate the fiber to prevent short circuiting (effective nerve impulse transmission) • Active nucleus and protein synthetic machinery for synthesis of neurotransmitters
Hepatocytes (liver), the interface between GUT & the systemic circulation Gallbladder & gut Systemic blood Controlled release of materials Bile duct Hepatic vein Gut Monosacharides Amino acids Fatty acids Nucleic acids Minerals Vitamins Drugs Poisons & chemicals Synthesis Storage Secretion Detoxification Scavenging Absorption Portal vein 80% Hepatic artery 20% Systemic blood Oxgenated blood
Basic cellular arrangement Central vein Fenestrated, discontinuous endothelium sinusoid Space of Disse Portal veinule Hepatic arteriole Bile duct Portal space
Liver is a factory Product output, Storage Raw materials Electricity
Conclusion Structural adaptations of the cell are for the function