FMN - Farmácia - Fisiologia da Secreção Gastrointestinal
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FMN - Farmácia - Fisiologia da Secreção Gastrointestinal


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Prof. MSc. Fábio Torres Cunha
Faculdade Maurício de Nassau
Departamento de Farmácia
Fisiologia Humana
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Resumo das secreções exócrinas do TGI
Modificado de: Vander, Sherman & Luciano, 2002
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EXÓCRINA 
(mucosa, serosa e/ou hidroeleletrolítica)
Tipos de secreções do TGI
ENDÓCRINA
 (hormônios)
NEURÓCRINA
 (neurotransmissores e/ou 
neuromoduladores)
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A secreção gástrica
extraído de: Vander, Sherman & Luciano, 2002 
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Veja mais em: http://mcb.berkeley.edu/courses/mcb136/topic/Gastrointestinal/Secretion_in_GI-Tract/ 
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http://anatomy.iupui.edu/courses/histo_D502/D502f04/d502f08sched.html 
células mucosas
células principais
células parietais
muco e HCO3-
pepsinogênio
HCl e Fator Intrínseco
SECREÇÕES EXÓCRINAS
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Veja mais em: http://mcb.berkeley.edu/courses/mcb136/topic/Gastrointestinal/Secretion_in_GI-Tract/ 
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Veja mais em: http://mcb.berkeley.edu/courses/mcb136/topic/Gastrointestinal/Secretion_in_GI-Tract/ 
Secreções gástricas
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Interações das secreções gástricas
mucous
extraído de: Vander, Sherman & Luciano, 2002 
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The protection provided to the mucosal surface of the stomach by the bicarbonate-containing mucus layer is known as the gastric mucosal barrier. In man, the mucus layer is about 0.2 mm thick. Buffering by the bicarbonate-rich secretions of the surface epithelial cells and the restraint to convective mixing caused by the high viscosity of the mucus layer allow the pH at the cell surface to remain near 7, whereas the pH in the gastric juice in the lumen is 1 to 2. 
COX1: atividade ciclooxigenase da PGH2-sintase). Berne et al., 2004 e outros: http://meds.queensu.ca/medicine/physiol/undergrad/phase2/phase2e/Ph2acid.htm 
\uf0e9 secreção de muco e HCO3- pelas 
 células epiteliais e mucosas
\uf0e9 fluxo sangüíneo
\uf0c5
camada mucosa (2mm)
Proteção mucosa
PGE2
( prostaglandinas 
são citoprotetoras)
ACh
(PS e SNE)
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Células \u201cG\u201d secretoras de GASTRINA
extraído, enquanto disponível, de: http://calloso.med.mun.ca/~tscott/digest/digtut.htm
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Regulação da secreção ácida gástrica
na fase cefálica
http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digestion/stomach/index.html 
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Regulação da secreção ácida gástrica
na fase gástrica
http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digestion/stomach/index.html 
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Regulação da secreção ácida gástrica
na fase intestinal
http://arbl.cvmbs.colostate.edu/hbooks/pathphys/digestion/stomach/index.html 
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SECREÇÕES EXÓCRINAS
PANCREÁTICA E HEPÁTICA
http://www.nlm.nih.gov/medlineplus/ency/imagepages/1090.htm 
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VOLUME SECRETADO PELO PÂNCREAS NO INTESTINO DELGADO:
1,5 L/DIA
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secreção hidro-eletrolítica
enzimas digestivas
(proteases, amilase e lipases)
Principais tipos celulares encontrados no pâncreas
Ilhotas de Langerhans
hormônios: insulina (cél. \u3b2), glucagon (cél. \u3b1), somatostatina (cél. \u3b4) e polipeptídeo pancreático (cél. \u3b8)
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ilhota (células alfa: glucagon)
ilhota (células beta: insulina)
ácinos e ilhota de Langerhans
http://www.udel.edu/Biology/Wags/histopage/histopage.htm 
HISTOLOGIA DO PÂNCREAS
PORÇÃO ENDÓCRINA 
(hormônios: glucagon, insulina, somatostatina e polipeptídeo pancreático)
PORÇÃO EXÓCRINA 
enzimas e secreção hidroeletrolítica
http://www.gastroslides.org/main/browse_deck.asp?tpc=6&mxpg=390&pg=2241#image 
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The relationships and major features of the units of the exocrine pancreas. The pancreatic acinar cells of the acinus have prominently stained zymogen granules in the apical area of the cell.  The connecting ductule does not contain zymogen granules. The blue cell in the cartoon depicts the centroacinar cell at the border between the acinus and ductule. The centroacinar cell functions similarly to the duct cell. The major secretory products of the acinus are digestive proenzymes and enzymes with lesser amounts of water and ions. The major secretory products of the duct are water and ions.
http://www.gastroslides.org/main/browse_deck.asp?tpc=6&mxpg=390&pg=2243#image 
AS SECREÇÕES EXÓCRINAS PANCREÁTICAS: 
água e eletrólitos
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The relationships and major features of the units of the exocrine pancreas. The pancreatic acinar cells of the acinus have prominently stained zymogen granules in the apical area of the cell.  The connecting ductule does not contain zymogen granules. The blue cell in the cartoon depicts the centroacinar cell at the border between the acinus and ductule. The centroacinar cell functions similarly to the duct cell. The major secretory products of the acinus are digestive proenzymes and enzymes with lesser amounts of water and ions. The major secretory products of the duct are water and ions.
http://www.gastroslides.org/main/browse_deck.asp?tpc=6&mxpg=390&pg=2243#image 
AS SECREÇÕES EXÓCRINAS PANCREÁTICAS: 
água e eletrólitos
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Neutralization of gastric acid delivered to the duodenum is necessary for optimal digestion and absorption of a meal. Several mechanisms that are not shown are involved in the neutralization process. First, the meal provides buffers from digestion of protein and triglycerides. That is, the peptides and fatty acid products act as pH buffers. Another neutralization process is absorption of hydrogen ion by the duodenal mucosa. Finally, the pancreas, biliary system and duodenal mucosa secrete bicarbonate into the duodenal lumen for neutralization. 
http://www.gastroslides.org/main/browse_deck.asp?tpc=6&mxpg=390&pg=2287#image 
Importância da secreção hidroeletrolítica pancreática, rica em HCO3-, Na+ e água na digestão
NaHCO3 + HCl \uf0f0 NaCl + H2O + CO2 (reabsorção)
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The relationships and major features of the units of the exocrine pancreas. The pancreatic acinar cells of the acinus have prominently stained zymogen granules in the apical area of the cell.  The connecting ductule does not contain zymogen granules. The blue cell in the cartoon depicts the centroacinar cell at the border between the acinus and ductule. The centroacinar cell functions similarly to the duct cell. The major secretory products of the acinus are digestive proenzymes and enzymes with lesser amounts of water and ions. The major secretory products of the duct are water and ions.
http://www.gastroslides.org/main/browse_deck.asp?tpc=6&mxpg=390&pg=2243#image 
AS SECREÇÕES EXÓCRINAS PANCREÁTICAS: ENZIMAS
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(from duodenal epithelial cells)
a-Amylase (no activation needed)
secreted by duodenal epithelium
(Enterokinase)
AS SECREÇÕES EXÓCRINAS PANCREÁTICAS: enzimas
lipase
http://mcb.berkeley.edu/courses/mcb136/topic/Gastrointestinal
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(from duodenal epithelial cells)
a-Amylase (no activation needed)
secreted by duodenal epithelium
(Enterokinase)
http://mcb.berkeley.edu/courses/mcb136/topic/Gastrointestinal
AS SECREÇÕES EXÓCRINAS PANCREÁTICAS: enzimas
lipase
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Relative amounts (by weight) of the different classes of pancreatic digestive enzymes. Proteases are the most abundant class of enzymes. 
http://www.gastroslides.org/main/browse_deck.asp?tpc=6&mxpg=390&pg=2273#image 
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(from duodenal epithelial cells)
a-Amylase (no activation needed)
secreted by duodenal epithelium
(Enterokinase)
http://mcb.berkeley.edu/courses/mcb136/topic/Gastrointestinal
AS SECREÇÕES EXÓCRINAS PANCREÁTICAS: enzimas
lipase
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Lipase pancreática
A secreção serosa pancreática: lipase pancreática
alfa-amilase pancreática:
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A secreção serosa pancreática: alfa-amilase
Amilopectina (amido) da batata
OBS: reparou que é a mesma ação da alfa-amilase salivar?
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A secreção serosa pancreática:
a ativação das pró-proteases pancreáticas no intestino delgado pela enteroquinase (da borda-em-escova)
extraído de: Vander, Sherman & Luciano, 2002 
Vander, Sherman e Luciano, 1997
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A secreção serosa pancreática:
a ativação das pró-proteases pancreáticas no intestino delgado pela enteroquinase (da borda-em-escova)